Rapid Prototyping

CNC punch press/laser builder sets up in Japan

2008-05-25T15:52:00.000-07:00

German builder of CNC punch press, laser cutting and profiling and sheet metal working equipment, Trumpf, has invested US$14 million in a 4500m2 production plant in Japan.

Europe's largest machine tool manufacturer is to develop and produce sheet metal working automation concepts in Fukushima, Japan Trumpf, based in Ditzingen, Germany believed it is the first German machine tool manufacturer to launch production on Japanese soil

Head of the Trumpf Machine Tool and Power Tool Division, Dr Mathias Kammueller, said: "We are crowning 30 successful years with our Japanese sales and service company by setting a further milestone.

Our new subsidiary Trumpf Manufacturing Japan produces and also develops automation and warehousing concepts".

The new production site is located in Fukushima, 250km north of Tokyo.

Before the opening on April 22, 2008, six months of extensive reconstruction and renovation work had to be accomplished on the former site of an automotive industry supplier.

The excellent infrastructure with access to train and highways played an important role in the location selection.

In the first investment phase, 35 employees will work in a 4,500m2 production plant.

It is located on a 31.000m2 area that allows a further extension.

So far Trumpf has invested more than US$14 million.

The products manufactured in Fukushima are primarily aimed at application in Japan.

In combination with the compact and automated Trumpf sheet metal processing machines these comply especially well with the requirements of the Japanese market due to their comparatively small foot print.

The new production site will work closely with local suppliers to increase competitive advantage.

Trumpf told manufacturingtalk that Japan is among the top five markets worldwide.

The company's involvement in the 'land of the rising sun' has a long tradition.

In 1977, Trumpf started off with sales and services of machine tools for the local market.

Today, the company offers its complete range of products and reached sales of EUR 100 million (1.55 billion Yen) in fiscal year 2006/07.

Around 180 employees work for Trumpf in Japan including those of the new production site in Fukushima.

Dr Kammueller said: "The country represents a vital building block in our growth strategy for Asia.

Localizing production is another well thought-out step within this long-term expansion strategy".

At this week's MACH 2008 machine tool exhibition in the UK, the new managing director for Trumpf in the UK, Hartmut Pannen, told manufacturingtalk that the Japanese plant will also serve Asia and the Americas.

Trumpf had, in 2007, also set up an automation systems plant in the Czech Republic not far from Plsen.

Pannen added that Trumpf has a full order book and has exhibited an annual growth rate of 15%/year over the last 20 years.

Turnover in 2007 had reached EUR 1.98bn and the company forecasted more growth during 2008.

Automated CNC laser cutter is very flexible

2008-05-23T03:34:00.000-07:00

Trumpf showed its compact, flexible TruLaser 2030 CNC 3.2kW sheet material cutting and profiling cell with automated work handling and higly durable laser resonator.

Trumpf's TruLaser 2030 was shown at this week's MACH 2008 machine tool exhibition at the NEC, Birmingham, UK It is sold as an 'off the shelf' automated machine that includes Trumpf's latest laser resonator, cutting process and automated material handling

Its integral load and unload equipment provides a compact and highly productive flexible manufacturing cell.

The flat bed laser has the high powered 3.2kW TruCoax CO2 diffusion-cooled laser that delivers exceptional beam quality.

This is a compact and highly durable laser whose high-frequency excitation requires minimal gas consumption by comparison with direct current excitation.

Thanks to its magnetic turbo radial blowers the laser also requires little maintenance.

The laser will cut mild steel up to 20mm thick, stainless steel up to 10mm and aluminium up to 8mm thick.

One common laser head will cut different thicknesses.

The laser head is also lighter, having a body of titanium.

* Operation - to start production the vacuum frame of the TruLaser 2030 lifts the blank sheet from the loading station, moves it onto the workstation and places it on the cutting table.

The frame then leaves the work area and prepares the next blank for processing.

At the end of the production cycle and unloading forks remove the finished parts including any sheet skeletons.

Other key features of the TruLaser 2030 include the following.

A moving enclosure that provides safe operation with easy access to the processing area.
The machine is available in two working area sizes allowing fabricators to use the material size that best fits their needs.
The options are 3m x 1.25m or 3m x 1.5m; Z axis is 115mm.

Nanotechnology

2008-04-22T02:18:00.000-07:00

Nanotechnology is now finding applications in numerous consumer products, ranging from sunscreen and cosmetics to sporting goods and guitar strings.

Heavily filled with non-crystalline nanoparticles, Nanotool resin is one of the Protocomposite materials available from DSM Somos (Fig.1). When cured, it is a ceramic-like material with a flexural modulus of 10500MPa, a heat deflection temperature of 260°C (at 0.46MPa after thermal post-cure), a Shore D hardness of 94 and very low linear shrinkage.DSM Somos says the resin also offers excellent side wall quality, which reduces the amount of finishing time required and makes it attractive for applications that requiring highly finished parts. As well as being suitable for rapid tooling used in injection moulding applications, Nanotool is also suitable for the production of high-quality models for wind tunnel testing and parts that can be metal-plated as prototypes for cast metal components (metal casting).

Nanotool can be used with the stereolithography process to create tooling inserts capable of moulding hundreds or, in some cases, thousands of parts from thermoplastics such as polyethylene, polypropylene, thermoplastic elastomers, high-impact polystyrene, ABS, polycarbonate and glass-filled nylon (Fig.2). These moulded parts would typically be used for performance testing or marketing studies, though the quality and structural integrity of the parts mean that they can also be suitable as production parts for short-run applications, provided the relatively long moulding cycle time of 60–120s is acceptable. For tooling that would traditionally require extensive electro-discharge machining, the rapid tooling process is likely to be more cost-effective than machined metal tooling. In addition, turnaround times can be very short, with moulded parts available in as little as three to five days.

As a guideline, DSM Somos suggests that Nanotool should be used for components up to approximately 100mm in size with ribs no less than 1.6mm thick due to the relatively brittle nature of the material. A minimum draft angle of 2degrees is recommended and, although sharp corners can be produced, the company cautions that this can reduce the life of the tool. For complex components, hand loaded cores can be used, and metal inserts remain an option for tall or thin-walled features that would be difficult to tool in Nanotool. So far we have discussed the use of Nanotool for rapid tooling, but the other application for which this material is proving popular is known as Metal Clad Composite (MC2) production (Fig.3). By coating a Nanotool part with a base layer of copper then a greater thickness of nickel, properties very similar to die cast or investment cast components can be created – but at a fraction of the cost. A metal-to-resin ratio of 20-30percent is said to result in a tensile strength similar to metals such as aluminium, zinc and magnesium. Alternatively, a coating of nickel just 0.05mm thick can be sufficient to provide good shielding against electromagnetic interference. In both cases, MC2 components are being used successfully for testing and real-world applications.

DSM Somos says that MC2 parts can be three or four times less expensive than parts that are investment cast or machined from solid, depending on the size and complexity. Furthermore, MC2 parts can be created in as little as one week. Prior to launching Nanotool, DSM Somos was already marketing Nanoform15120, which is another material taking advantage of nanotechnology. Similar in some ways to Nanotool, Nanoform15120 is a composite stereolithography material that incorporates non-crystalline nanoparticles to enhance its physical properties. In particular, Nanoform 15120 offers high stiffness, heat deflection temperatures of 265°C or more, exceptional dimensional stability and low moisture absorption.

DSM Somos is not alone in using nanotechnology to develop improved materials for rapid prototyping and manufacturing; 3D Systems proclaimed that its Accura Bluestone material was the first commercially available engineered nanocomposite resin for stereolithography (SLA) systems when it was launched in 2004. Accura Bluestone is capable of creating parts with high-stiffness, high temperature resistance, excellent dimensional accuracy and good resistance to moisture.

Capable of resisting temperatures as high as 250°C, the material is suitable for both high-temperature environments – such as in electronics enclosures and automotive engine bays – as well as for creating injection mould tooling. Other applications that benefit from the high stiffness and accuracy include wind-tunnel testing for the motorsports and aerospace industries, and the production of inspection and assembly jigs and fixtures. The combination of part accuracy and moisture resistance means Accura Bluestone can also be used for water-contact components in pumps and similar products. Post-cured Accura Bluestone has a tensile modulus of 7600 to 11,700MPa (!), a flexural modulus of 8300 to 9800MPa and a Shore D hardness of 92. Tempering technology Having reviewed some of the rapid prototyping and rapid manufacturing materials that utilise nanotechnology, it is also worth highlighting a novel technique that makes use of nanotechnology to modify the properties of parts built from conventional rapid prototyping and rapid manufacturing materials. RP Tempering is described as a solid freeform additive technology developed by Par3 Technology for use with parts built using stereolithography, laser sintering, fused deposition modelling and 3D printing systems. Whereas parts built using these systems are normally relatively fragile, the RP Tempering technology enables toughness to be improved (Fig.4). In addition, Par3 has developed alternative treatments for enhancing electromagnetic shielding, flame retardance and chemical resistance.

As well as modifying a component’s bulk characteristics, RP Tempering also enables living hinges to function, snap fits to be used numerous times, and self-tapping screws to be inserted into screw bosses.

To use RP Tempering, the part has to be built with a series of tunnels and surface grooves, depending on the part’s geometry. The tunnels are subsequently injected with the RP Tempering compound that contains multi-wall carbon nanotubes. Coating techniques are also used to apply RP Tempering compounds to the exterior and/or interior walls of the component.

When RP Tempering was first introduced, it was necessary to modify the CAD model prior to creating the STL file for rapid prototyping. However, Materialise has incorporated special functions in its 3-matic software that enables the tunnels and other features to be added directly to an STL file in a process that takes around 15minutes. In Europe, the Temperman Initiative has been established to promote RP Tempering, which is available through a number of service bureaux. The Temperman website has a series of short videos that illustrate very clearly the dramatic improvements that RP Tempering can make to components.

Nanotechnology brings ancient sarcophagus to life

2008-04-03T05:36:00.000-07:00

Nanotechnology brings ancient sarcophagus to life

(Nanowerk News) It was long believed that the statues and relief's of Greek and Roman antiquity were left in their natural state and unpainted, unlike contemporary works from other advanced civilizations like the Egyptians. Archaeologists have known for some time that this popular misconception of Western art was largely a renaissance creation. Classical marble carvings would have been painted originally, although it is rare for any of the polychromy to have survived to the present day. In most cases the colouring has been completely weathered and worn away over the centuries.

Breathing new life into the past

To illustrate this breakthrough in the understanding of ancient art, it was decided to show the world how vibrant these works of art would have looked in their original form. This involved creating reproduction pieces for a special travelling exhibition organized by the Glyptothek museum in Munich, Germany. The project was led by archaeologist Prof. Vinzenz Brinkmann, a leading authority in this field. It represents more than two decades of research on the polychromy of ancient sculpture, undertaken by the leading authorities in museums around the world, in collaboration with scholars from different countries. Paint fragments were analysed using modern techniques such as infrared spectroscopy and recreated with authentic pigments by Prof. Brinkmann and his team. With more than 20 full-size coloured reconstructions of important Greek and Roman works, 'Multicoloured Gods' breaks new ground as the first large-scale effort to recreate the original appearance of ancient sculpture. Starting off in Munich, the exhibition has toured major European cities and is now in the US.

The Alexander Sarcophagus

One of the exhibition's centre pieces is a section of the Alexander Sarcophagus attributed to the 4th Century BC Lydian King Abdalonymos. An ally of Alexander, Abdalonymos had the marble sarcophagus adorned with bas-relief depictions of scenes from the life of his great hero battling against the Persians. This relic, discovered in Lebanon and now housed in the museum of Istanbul, was one of those rare finds containing fragments of original colours, which were painstakingly analyzed and reproduced. It is believed that the Alexander Sarcophagus, was painted by Nicias, a renowned artist of the period who showed Alexander in a vivid red tunic, magenta cape and golden lion-skin headdress.

Preserving and reconstructing with Stereolithography

The first challenge with the sarcophagus was to make a replica section that was precise in every detail. The second challenge was to use a material with hardness and surface qualities similar to marble. A silicone mould could not be used to make an impression due to the danger that the precious paint fragments would be removed by the mold. It was therefore decide to use a scanning technology to generate a three dimensional data set. This was then used to build a more or less consistent 3D-file which could be used for producing the replica by stereolithography (SL), a process that uses photopolymer liquid resins which solidify when exposed to UV laser light. A software program transfers the designer's 3-D CAD model, or in this case a laser scanned file, into an electronic file for SL machines, composing the information into thin cross sections or layers. A laser beam then traces each layer onto the surface of a vat of photopolymer resin, building the part in repeated layers until a solid replica of the original is completed.

Alphaform AG, a German based specialist service bureau was approached by Professor Brinkmann's team to reproduce the part. Alphaform had previously created pieces of art for well known artists like Andrew Barov and the "Bayrische See- und Schlösserverwaltung" - an institution responsible for preserving pieces of art and ancient buildings in the south of Germany. As Alphaform Director Ralf Deuke recalls: "These kind of projects are far removed from our usual rapid prototyping work, for example for automotive and Formula 1 where we receive well designed files with good surfaces."

"The project generated a number of specific challenges: The scan contained a lot of defects due to a combination of the protective glass cover and the space limitations around the original piece in the Istanbul museum. Another big challenge was that the file generated thousands of supports. Some structural supports are necessary while the part is being manufactured using the SL process but not thousands! We therefore had to use our experience and know-how to find a good compromise and produce a file that the machines were able to handle and which showed minimal defects."

NanoTool for precision detailing

To faithfully reproduce the fine detail of the piece also required an SL material with hardness and surface qualities similar to marble. Although Alphaform also use laser sintering techniques [SLS] they decided to use SL because of its superior surface finish and detail resolution. Being thermoplastics, SLS materials can't reproduce mineral-like qualities. The material that could was the SL photopolymer NanoTool® from DSM Somos: a high modulus material designed for high-end engineering applications - in automotive and wind-tunnel testing as well as for rapid tooling. NanoTool is heavily filled with non-crystalline nanoparticles allowing for faster processing. Being a virtually zero shrinkage polymer, build lines don't detract from the smooth finish.

"We have a lot of experience with NanoTool for the rapid prototyping of F1 aero sections and other parts that need high surface quality," continued Deuke, "it provides extremely fine detail resolution compared to other SL materials. Professor Brinkmann evaluated the material and found it easy to finish and paint - far superior to the plaster normally used to create replicas."

"After first creating a small section less than half a meter wide [shown above] we move on to replicating a full three meter side of the sarcopghagus. The complete piece was built in three sections which were then seamlessly fitted together. Without rapid prototyping it would have been impossible to create this part. It's ironic that a material and process designed for next generation prototyping and rapid manufacturing has replicated a 2,500 year old sarcophagus!"

About DSM Somos

DSM Somos is one of the world's leading material suppliers to the rapid prototyping industry, providing stereolithography liquids used for the creation of three-dimensional models and prototypes directly from digital data. Somos' patented ProtoFunctional® materials are used by a variety of industries, including automotive, aerospace, medical and telecommunications.

DSM Somos is an unincorporated subsidiary of DSM Desotech-a world leader in the development of UVcurable materials-and a member of the global DSM family.

About Alphaform AG

With wholly owned subsidiary companies in German, Finland and the UK, Alphaform AG has evolved from a Rapid Prototyping service company into a production company of the future. Utilizing the most advanced production techniques, Alphaform customize the development and mass production of parts for a range of end-markets such as automotive, E&E, and medical. Services include rapid prototyping, metal coating, rapid tooling and small scale serial production.

Source: DSM Somos

2008-03-19T11:13:00.000-07:00

The Ink Jet Printing technology is also sometimes called Ballistic Particle Manufacturing. Other systems providers use considerably different techniques, but they all rely on squirting a build material in a liquid or melted state which cools or otherwise hardens to form a solid on impact. One example of the technology variations available in these so-called phase change inkjets is provided by 3D Systems. This company produces an inkjet machine, called the ThermoJet Modeler (formerly Actua), based on technology from Spectra, Inc. which utilizes several hundred nozzles. By contrast, the Solidscape machine uses a single jet each for build and support materials, and it serves as an introduction here. Plastic object, wax and support materials, are held in a melted liquid state at elevated temperature in reservoirs (A). The liquids are fed to individual jetting heads (B) through thermally insulated tubing. The jetting heads squirt tiny droplets of the materials as they are moved side by side in the required geometry to form the layer of the object. The heads are controlled and only place droplets where they are required to. The materials harden by rapidly dropping in temperature as they are deposited. After an entire layer of the object is formed by jetting, a milling head (C) is passed over the layer to make it a uniform thickness. Particles are vacuumed away as the milling head cuts and are captured in a filter (D). The operation of the nozzles is checked after a layer has been fabricated by depositing a line of each material on a narrow strip of paper and reading the result optically (E). If all is well, the elevator table (F) is moved down a layer thickness and the next layer is begun. If a clog is detected, a jetting head cleaning cycle is carried out. If the clog is cleared, the problem layers are milled off and then repeated. After the object is completed, the wax support material is either melted or dissolved away. The Solidscape system is capable of producing fine finishes, but to do so results in slow operation. Thus, there is a tradeoff between fabrication time and the amount of hand finishing required. Fused Deposition Modeling Figure 1 is a schematic of this method. A plastic filament, approximately 1/16 inch in diameter, is unwound from a coil (A) and supplies material to an extrusion nozzle (B). The nozzle is heated to melt the plastic and has a mechanism which allows the flow of the melted plastic to be controlled. The nozzle is mounted to a mechanical stage (C) which can be moved in horizontal and vertical directions. As the nozzle is moved over the table (D) in the required geometry, it deposits a thin bead of extruded plastic to form each layer. The plastic hardens immediately after being squirted from the nozzle and bonds to the layer below. The entire system is contained within an oven chamber which is held at a temperature just below the melting point of the plastic. Thus, only a small amount of additional thermal energy needs to be supplied by the extrusion nozzle to cause the plastic to melt. This provides much better control of the process. Support structures must be designed and fabricated for any overhanging geometries and are later removed in secondary operations. Several materials are available for the process including a nylon-like polymer and both machinable and investment casting waxes. The introduction of ABS plastic material has led to greater commercial acceptance of the method. It provides better layer to layer bonding than previous materials and also has a companion support material which is easily removable by simply breaking it away from the object. Laminated Object Manufacturing Figure 2 presents a schematic of this method as implemented in systems sold by Helisys. Profiles of object cross sections are cut from butcher paper using a laser. The paper is unwound from a feed roll (A) onto the stack and bonded to the previous layer using a heated roller (B). The roller melts a plastic coating on the bottom side of the paper to create the bond. The profiles are traced by an optics system that is mounted to an X-Y stage (C). The process generates considerable smoke. Either a chimney or a charcoal filtration system is required (E) and the build chamber must be sealed. After cutting the geometric features of a layer is completed, the excess paper is cut away to separate the layer from the web. The extra paper of the web is wound on a take-up roll (D). The method is self-supporting for overhangs and undercuts. Areas of cross sections which are to be removed in the final object are heavily cross-hatched with the laser to facilitate removal. It can be time consuming to remove extra material for some geometries. The finish and accuracy are not as good as with some methods, however objects have the look and feel of wood and can be worked and finished in the same manner. Variations on this method have been developed by many companies and research groups. Kira's Paper Lamination Technology (PLT) uses a knife to cut each layer instead of a laser and applies adhesive to bond layers using the xerographic process. Other variations include Thick Layer Lamination from Stratoconception of France, Precision Stratiform Machining from Ford Research, and Adaptive-Layer Lamination developed by Landfoam Topographics. These are hybrids of additive and subtractive CNC technologies which seek to increase speed and material versatility by cutting the edges of thick layers to avoid stair stepping. Solid Ground Curing The early versions of the system weighed several tons and required a sealed room. Size has been decreased and the system has been sealed to prevent exposure to photopolymers, but it's still very large. Please see the discussion on stereolithography for a description of photopolymers. Instead of using a laser to expose and harden photopolymer element by element within a layer as is done in stereolithography, SGC uses a mask to expose the entire object layer at once with a burst of intense UV light. The method of generating the masks is based on electrophotography (xerography). This is a two cycle process having a mask generation cycle and a layer fabrication cycle. It takes about 2 minutes to complete all operations to make a layer: 1. First the object under construction (A) is given a coating of photopolymer resin as it passes the resin applicator station (B) on its way to the exposure cell (C). 2. A mask is generated by electrostatically transferring toner in the required object cross sectional image pattern to a glass plate (D) An electron gun writes a charge pattern on the plate which is developed with toner. The glass plate then moves to the exposure cell where it is positioned above the object under construction. 3. A shutter is opened allowing the exposure light to pass through the mask and quickly cure the photopolymer layer in the required pattern. Because the light is so intense the layer is fully cured and no secondary curing operation is necessary as is the case with stereolithography. 4. The mask and object under fabrication then part company. The glass mask is cleaned of toner and discharged. A new mask is electrophotographically generated on the plate to repeat the cycle. 5. The object moves to the aerodynamic wiper (E) where any resin that wasn't hardened is vacuumed off and discarded. 6. It then passes under a wax applicator (F) where the voids created by the removal of the unhardened resin are filled with wax. The wax is hardened by moving the object to the cooling station (G) where a cold plate is pressed against it. 7. The final step involves running the object under the milling head (H). Both the wax and photopolymer are milled to a uniform thickness and the cycle is repeated until the object is completely formed within a wax matrix. Secondary operations are required to remove the wax. It can either be melted away or dissolved using. Stereolithography The implementation shown in figure 3 is used by 3D Systems and some foreign manufacturers. A moveable table, or elevator (A), initially is placed at a position just below the surface of a vat (B) filled with liquid photopolymer resin (C). This material has the property that when light of the correct color strikes it, it turns from a liquid to a solid. The most common photopolymer materials used require an ultraviolet light, but resins that work with visible light are also utilized. The system is sealed to prevent the escape of fumes from the resin. A laser beam is moved over the surface of the liquid photopolymer to trace the geometry of the cross-section of the object. This causes the liquid to harden in areas where the laser strikes. The laser beam is moved in the X-Y directions by a scanner system (D). These are fast and highly controllable motors which drive mirrors and are guided by information from the CAD data. The exact pattern that the laser traces is a combination of the information contained in the CAD system that describes the geometry of the object, and information from the rapid prototyping application software that optimizes the faithfulness of the fabricated object. Of course, application software for every method of rapid prototyping modifies the CAD data in one way or another to provide for operation of the machinery and to compensate for shortcomings. After the layer is completely traced and for the most part hardened by the laser beam, the table is lowered into the vat a distance equal to the thickness of a layer. The resin is generally quite viscous, however. To speed this process of recoating, early stereolithography systems drew a knife edge (E) over the surface to smooth it. More recently pump-driven recoating systems have been utilized. The tracing and recoating steps are repeated until the object is completely fabricated and sits on the table within the vat. Some geometries of objects have overhangs or undercuts. These must be supported during the fabrication process. The support structures are either manually or automatically designed. Upon completion of the fabrication process, the object is elevated from the vat and allowed to drain. Excess resin is swabbed manually from the surfaces. The object is often given a final cure by bathing it in intense light in a box resembling an oven called a Post-Curing Apparatus (PCA). Some resins and types of stereolithography equipment don't require this operation, however. After final cure, supports are cut off the object and surfaces are sanded or otherwise finished. Stereolithography generally is considered to provide the greatest accuracy and best surface finish of any rapid prototyping technology. Work continues to provide materials that have wider and more directly useable mechanical properties. Selective Laser Sintering The process is somewhat similar to stereolithography in principle as can be seen from figure 4. In this case, however, a laser beam is traced over the surface of a tightly compacted powder made of thermoplastic material (A). The powder is spread by a roller (B) over the surface of a build cylinder (C). A piston (D) moves down one object layer thickness to accommodate the layer of powder. The powder supply system (E) is similar in function to the build cylinder. It also comprises a cylinder and piston. In this case the piston moves upward incrementally to supply powder for the process. Heat from the laser melts the powder where it strikes under guidance of the scanner system (F). The CO2 laser used provides a concentrated infrared heating beam. The entire fabrication chamber is sealed and maintained at a temperature just below the melting point of the plastic powder. Thus, heat from the laser need only elevate the temperature slightly to cause sintering, greatly speeding the process. A nitrogen atmosphere is also maintained in the fabrication chamber which prevents the possibility of explosion in the handling of large quantities of powder. After the object is fully formed, the piston is raised to elevate the object. Excess powder is simply brushed away and final manual finishing may be carried out. No supports are required with this method since overhangs and undercuts are supported by the solid powder bed. This saves some finishing time compared to stereolithography. However, surface finishes are not as good and this may increase the time. No final curing is required as in stereolithography, but since the objects are sintered they are porous. Depending on the application, it may be necessary to infiltrate the object with another material to improve mechanical characteristics. Much progress has been made over the years in improving surface finish and pororsity. The method has also been extended to provide direct fabrication of metal and ceramic objects and tools. This article was written by C. Kaan Senol in 2003.

Rapid Prototyping and Direct Digital Manufacturing Services Now Available in Australasia

2008-02-27T01:16:00.001-08:00

We've posted on RedEye RPM before; they are the service bureau arm of Stratasys, who manufacture various types of 3D print gear. This announcement ensures strong access to 3D print services for those in Australia and surrounding regions. Details about the service can be found at this post.

RedEye RPM ’s new location in Melbourne, Australia offers fused deposition modeling® technology to Australia and New Zealand

EDEN PRAIRIE, Minn.--(BUSINESS WIRE)--RedEye RPM (www.redeyerpm.com), a provider of rapid prototyping and direct digital manufacturing services, today announced the expansion of its operations to a new location in Melbourne, Australia.

Our FDM technology will give designers and engineers in Australasia a new opportunity to quickly produce functional prototypes and parts, ” said Jeff Hanson, manager of business development for RedEye RPM. “ A great deal of design and development is performed in that region. Our partnership with RapidPro allows us to produce parts for testing, concept validation and even end-use in a number of industries, including aerospace, automotive and medical; through to consumer and white goods. ”

RedEye RPM is a business unit of Stratasys, the creator of FDM technology, an additive fabrication process that uses production-grade thermoplastic materials to build functional, durable models and parts in one piece. RapidPro, the Melbourne-based rapid-prototyping group, will serve as the host facility for RedEye RPM (Australia) and will run and maintain the systems.

"The Australasian market can now enjoy the benefits of the prototypes and/or short-run production parts being generated by top-end FDM machines in high-performance engineering materials," says Simon Bartlett, managing director of RapidPro.

From its Australian manufacturing center, RedEye RPM Australasia can build and ship parts throughout Australia and New Zealand. RapidPro will build models and parts in a range of engineering thermoplastic materials, such as a 140+ degree C (300 degree F) polyphenylsulfone material and a material approved for medical (meet ISO 10993-1) applications.

About RedEye RPM

RedEye RPM, a business unit of Stratasys, Inc., provides rapid prototyping and direct digital manufacturing services worldwide. With more than 80 systems in its facilities, RedEye RPM produces low-volume models and functional parts made from one of the largest selections of thermoplastic materials available for rapid prototyping, such as ABS, polycarbonate, ISO-certified PC and more. From digital files, RedEye builds models and parts of any size, while maintaining design accuracy, and allows for multiple iterations throughout the design process. For instant online quoting or more information, visit au.redeyerpm.com.

Stratasys Inc., Minneapolis, manufactures additive fabrication machines for 3D printing, prototyping, and direct digital manufacturing. According to Wohlers Report 2007, Stratasys supplied 41 percent of all such systems installed worldwide in 2006, making it the unit market leader for the fifth consecutive year. Stratasys owns the RapidPrototyping process known as fused deposition modeling (FDM). The process creates functional prototypes and end-use parts directly from any 3D CAD program, using ABS plastic, polycarbonate, PPSF, and blends. The company holds more than 180 granted or pending additive fabrication patents globally. Stratasys products are used in the aerospace, defense, automotive, medical, education, electronic, and consumer product industries. On the Web: www.Stratasys.com; www.DimensionPrinting.com; and www.RedEyeRPM.com.

About RapidPro

RapidPro is a specialist prototype and short run production supplier to all industries. The key to their success is understanding customers requirements and brain storming the ideal solution. In going through this process they apply the latest “

Forward Looking Statement

All statements herein that are not historical facts or that include such words as “expects ”, “anticipates ”, “projects ”, “estimates ” or “believes ” or similar words are forward-looking statements that we deem to be covered by and to qualify for the safe harbor protection covered by the Private Securities Litigation Reform Act of 1995. Our belief that we have the largest part-building service claim is based on the number of dedicated machines. Except for the historical information herein, the matters discussed in this news release are forward-looking statements that involve risks and uncertainties; these include the continued market acceptance and growth of our Dimension^TM line, Prodigy Plus, FDM Maxum^TM, FDM Vantage^TM, and Titan^TM product lines; the size of the 3D printing market; our ability to penetrate the 3D printing market; our ability to maintain the growth rates experienced in this and preceding quarters; our ability to introduce and market new materials such as PC-ABS and the market acceptance of this and other materials; the impact of competitive products and pricing; the timely development and acceptance of new products and materials; our ability to effectively and profitably market and distribute the Arcam product line; the success of our recent R&D initiative to expand the rapid manufacturing capabilities of our core FDM technology; the success of our RedEye RPM^TM and other parts services; and the other risks detailed from time to time in our SEC Reports, including the annual report on Form 10-K for the year ended December 31, 2006 and 10-Q filed throughout 2007.

Design of Experiment ” problem solving techniques, using Six Sigma methodologies. The result - a complete Rapid Prototyping solution. All done through a team of engineers with over 40 years of combined experience in a wide variety of design and development roles. More than just a part supplier, better thought of as an extension to your engineering team. On the web www.rapidpro.com.au and redeyerpm.com.au

Nanotechnology and rapid prototyping/manufacturing

2008-02-22T03:13:00.000-08:00

Leading suppliers of materials for rapid prototyping and rapid manufacturing are finding that nanoparticles can dramatically alter the properties of finished components. Paul Stevens looks at what is available on the market and how another nanotechnology-based process is enhancing the properties of parts built from standard materials.

Nanotechnology is now finding applications in numerous consumer products, ranging from sunscreen and cosmetics to sporting goods and guitar strings. In the field of rapid prototyping and rapid manufacturing, nanotechnology is also now offering advantages to new product development teams.

In this article we will look at materials for tooling and model building, as well as an innovative technology that improves the performance of standard materials used for rapid prototyping and rapid manufacturing.

Heavily filled with non-crystalline nanoparticles, Nanotool resin is one of the Protocomposite materials available from DSM Somos. When cured, it is a ceramic-like material with a flexural modulus of 10,500 MPa, a heat deflection temperature of 260˚C (at 0.46 MPa after thermal post-cure), a Shore D hardness of 94 and very low linear shrinkage.

DSM Somos says the resin also offers excellent side wall quality, which reduces the amount of finishing time required and makes it attractive for applications that requiring highly finished parts. As well as being suitable for rapid tooling used in injection moulding applications, Nanotool is also suitable for the production of high-quality models for wind tunnel testing and parts that can be metal-plated as prototypes for cast metal components (metal casting).

Nanotool can be used with the stereolithography process to create tooling inserts capable of moulding hundreds or, in some cases, thousands of parts from thermoplastics such as polyethylene, polypropylene, thermoplastic elastomers, high-impact polystyrene, ABS, polycarbonate and glass-filled nylon. These moulded parts would typically be used for performance testing or marketing studies, though the quality and structural integrity of the parts mean that they can also be suitable as production parts for short-run applications, provided the relatively long moulding cycle time of 60–120 s is acceptable. For tooling that would traditionally require extensive electro-discharge machining, the rapid tooling process is likely to be more cost-effective than machined metal tooling. In addition, turnaround times can be very short, with moulded parts available in as little as three to five days.

Nickel plating

So far we have discussed the use of Nanotool for rapid tooling, but the other application for which this material is proving popular is known as Metal Clad Composite (MC2) production. By coating a Nanotool part with a base layer of copper then a greater thickness of nickel, properties very similar to die cast or investment cast components can be created - but at a fraction of the cost. A metal-to-resin ratio of 20-30 per cent is said to result in a tensile strength similar to metals such as aluminium, zinc and magnesium. Alternatively, a coating of nickel just 0.05 mm thick can be sufficient to provide good shielding against electromagnetic interference. In both cases, MC2 components are being used successfully for testing and real-world applications.

Prior to launching Nanotool, DSM Somos was already marketing Nanoform 15120, which is another material taking advantage of nanotechnology. Similar in some ways to Nanotool, Nanoform 15120 is a composite stereolithography material that incorporates non-crystalline nanoparticles to enhance its physical properties. In particular, Nanoform 15120 offers high stiffness, heat deflection temperatures of 265˚C or more, exceptional dimensional stability and low moisture absorption.

Capable of resisting temperatures as high as 250˚C, the material is suitable for both high-temperature environments – such as in electronics enclosures and automotive engine bays - as well as for creating injection mould tooling. Other applications that benefit from the high stiffness and accuracy include wind-tunnel testing for the motorsports and aerospace industries, and the production of inspection and assembly jigs and fixtures. The combination of part accuracy and moisture resistance means Accura Bluestone can also be used for water-contact components in pumps and similar products.

Post-cured Accura Bluestone has a tensile modulus of 7600 to 11 700 MPa, a flexural modulus of 8300 to 9800 MPa and a Shore D hardness of 92.

Tempering technology

Having reviewed some of the rapid prototyping and rapid manufacturing materials that utilise nanotechnology, it is also worth highlighting a novel technique that makes use of nanotechnology to modify the properties of parts built from conventional rapid prototyping and rapid manufacturing materials. RP Tempering is described as a solid freeform additive technology developed by Par3 Technology for use with parts built using stereolithography, laser sintering, fused deposition modelling and 3D printing systems. Whereas parts built using these systems are normally relatively fragile, the RP Tempering technology enables toughness to be improved considerably. In addition, Par3 has developed alternative treatments for enhancing electromagnetic shielding, flame retardance and chemical resistance.

To use RP Tempering, the part has to be built with a series of tunnels and surface grooves, depending on the part's geometry. The tunnels are subsequently injected with the RP Tempering compound that contains multi-wall carbon nanotubes. Coating techniques are also used to apply RP Tempering compounds to the exterior and/or interior walls of the component.

When RP Tempering was first introduced, it was necessary to modify the CAD model prior to creating the STL file for rapid prototyping. However, Materialise has incorporated special functions in its 3-matic software that enables the tunnels and other features to be added directly to an STL file in a process that takes around 15 minutes. In Europe, the Temperman Initiative has been established to promote RP Tempering, which is available through a number of service bureaux. The Temperman website has a series of short videos that illustrate very clearly the dramatic improvements that RP Tempering can make to components.

Nanotechnology has already found its way into hundreds of consumer products because of the diverse benefits that are available. As the foregoing illustrates, nanotechnology is also starting to make an impact on the world of rapid prototyping and rapid manufacturing.

engineerlive.com

'First Metal Cut' on Taranis tech program

2007-11-26T02:47:00.000-08:00

Farnborough, England, Nov. 13 (UPI) - British company BAE Systems has carried out the successful 'First Metal Cut' on its $250 million Taranis Technology Demonstrator program.

The Taranis program "will see the BAE Systems Hawk-sized Unmanned Combat Air Vehicle - UCAV - demonstrator begin a series of flight trials during 2010," the company said in a statement Monday.

BAE Systems said Taranis was a British Ministry of Defense-led project that was "supported by an industry consortium led by BAE Systems (which) will offer the (British) government a chance to assess the potential of UCAVs in terms of Deep Persistent Offensive Capability and will help the armed forces inform the balance of the future Force Mix."

BAE Systems said it had "made a significant investment over several years in the development of UAS capabilities before winning the Taranis TDP contract where it is working alongside three other Tier 1 partners: QinetiQ, Rolls-Royce and GE Aviation to deliver the four year program."

"Successful trials with UAV platforms such as CORAX, RAVEN and HERTI have all combined to ensure BAE Systems now has the lean manufacturing and rapid prototyping capabilities needed to further develop in this highly competitive market sector,"

the company said.

BAE Systems describes itself as "the premier global defense and aerospace company delivering a full range of products and services for air, land and naval forces, as well as advanced electronics, information technology solutions and customer support services. With 96,000 employees worldwide, BAE Systems' sales exceeded $27 billion in 2006."

3D printing with Metal

2007-10-25T00:55:00.000-07:00

3D printing with Metals

by Fernando Ribeiro

Universidade do Minho Industrial Electronics Dep. Campus de Azurém 4800 Guimarães PORTUGAL

Rapid Prototyping is a recently developed technique that ‘prints’ a component, instead of manufacturing it in traditional terms, by using materials ranging from photopolymers to thermoplastics, including paper. Since these materials are in most cases not suitable for assessement purposes a new approach has been created. It has similar ‘build up’ technique but uses metal as raw material. The process entails the use of a gas metal arc fusion welding robot which deposits successive layers of metal in such a way that it forms a 3D solid component. This process can also be considered a manufacturing process for low volume production.

INTRODUCTION

It takes many months or sometimes years from the time that a company takes the decision to introduce a new product to the market until the product reaches that market. It would be very desirable to reduce this product-development cycle time in order to make the company more competitive and able to respond to changes in the market as quickly as possible. During the development cycle time, the task that often takes longest is the production of prototype components which may itself be costly and time consuming but also delays testing. If the prototype performance is not adequate the design may have to be changed and the prototype reproduced until it meets the design specification and executes the task for which it is intended. The design engineer would often prefer to see a physical model of the component in hours instead of weeks. It is also possible that the product cost can be reduced, with superior quality. Extra time will also be available to the design engineers to improve the quality and also to study new ways of producing the product in a more cost-effective way. To achieve this, a relatively new technology has being created and although there is no standard name for it yet, it is most commonly known as Rapid Prototyping (RP), solid freeform fabrication, layer manufacturing technology, near net manufacture or even 3D printing system. Rapid Prototyping has been growing very quickly, and some processes are commercially available like stereolithography, laminated object manufacturing (LOM) or fused deposition modelling (FDM).

The advantages are tremendous and some of them are:

The production time of a prototype is drastically shortened from months to weeks or even days.
These techniques are ‘automatic’ meaning less need to have a skilled operative, and it is also possible to leave the system working with little supervision around the clock.
Since these machines work as additive processes they are less wasteful of materials.
It is very easy to implement changes in the component since this is electronically drawn in a CAD package, being only necessary to ‘reprint’ it.

More than one part can be made at once, that number being limited only by the size of the working area.
But traditional RP processes also have some disadvantages like:

The maximum size of the prototype is limited by the machine working volume.
All these systems are very costly, well over £100,000 minimum each.
It is not always possible to make the prototype in the material required for final component (most of these techniques use wax, photopolymers, thermoplastics and ceramics or even paper for the initial model). Techniques which prototype components in 100% metal are not common although some attempts have been made.

Fig. 1 ‘Square component’ being ‘printed’ by rapid prototyping using fusion welding

To overcome these problems a technique for rapid prototyping components using robotic arc welding has been investigated at Cranfield University (UK) and is presented here. In this process the component is formed by melting and depositing the metal using the GMA welding process. A CAD drawing system is used to create the initial solid shape and a welding robot is used to manipulate the welding torch according to the component design. Another objective was to create a low price system since most traditional RP systems are very expensive. All the software runs on PC platform to reduce computer costs. Fig. 1 shows a component being ‘3D printed’ using robotic arc welding. Sometimes, it is very important not only to observe the prototype but also to test it and sometimes to use it to check its operability. For most industries, rapid prototyped samples have limited mechanical, thermal and chemical properties of the materials that can be manufactured (such as polymers, wax, nylon, paper, etc.). Since it is very important in some industries to make and test metallic components, a new rapid prototyping technique was necessary allowing metals to be deposited directly. To test parts, a CAD program or mathematical simulation package could be used, but as Phillip Ulerich said: ‘I find people need to fondle parts before they really understand them. Drawings just don’t do it’. It is therefore important to have the component in our hands to understand it. The technique presented in this article tries to solve the main limitations of traditional rapid prototyping processes and incorporates some new techniques for automating the process and these have proved to be extremely successful. With this process, metallic components were made with acceptable surface finish, acceptable structural conditions, in a shorter period of time and cheaper by avoiding the use of moulds. This process can also be a manufacturing technique for low volume production.

HOW THE PROCESS WORKS

The preprocessing of this rapid prototyping process is similar to traditional rapid prototyping processes. First the component is drawn as a 3D solid model in a CAD system. The design is created by the designer according to their requirements. Then, information relative to the component has to be ‘input’ into the system (part features parameters) like the part name, width, sequential order of build up, welding torch orientation, etc. Some of this information will then be used to generate automatically the appropriate welding parameters.

Fig. 2 Part features input screen

Fig. 2 shows the add-on part features input screen. All the empty fields in the Figure are automatically filled in according to the other input values. From all the other ones, only three have to be input for every component, all the others being assumed as default values which almost never change. Then, the solid model is electronically sliced by an AutoCAD add-on. It generates lines/polylines which represent the robot path necessary to make the component. Fig. 3 shows a sequence of drawings for a simple component and its resulting slices. These welding parameters are automatically generated and were derived from welding studies carried out by Norrish ¹ and parametric equations generated by Ogunbiyi and Norrish ².

Fig. 3 (left to write) Cross-section drawing (side view), its revolution (orthogonal view), final solid shaded, solid model with resulting slices (blue lines)

After the slices are generated, four outputs are created: the polylines as a DXF file (only required to export should a simulation be needed), the robot program (ARLA language for ABB robots), and two reports containing instructions relating to the component itself: one is for the welding technician and contains welding instructions and values for each layer (time, height, etc.); the other is for the production manager and contains information like the time it will take to build, the quantity of material needed, etc. The robot program is then compiled and download to the robot. Before the robot program is downloaded to the actual robot, it can be simulated with the use of a robot simulation program to check for collisions or other problems such as access, although this task is not compulsory. The robot program may then be modified if necessary. Fig. 4 shows a simulation picture of a robot making a vase.

Fig. 4 Simulation picture of a vase being made

The robot program (in text format) is then compiled and downloaded to the robot via a serial cable through the RS 232C port of the computer. A special program is necessary to perform this task since this robot only reads binary code. This particular binary file format is unique to each robot manufacturer. After setting up all the required consumables the robot is ready to start welding or in other words to start building up the component as far as the welding system is operational. It is important to point out that the metal to be used is entirely for the user to select. To build a component, a metal baseplate is necessary on which the beads will be deposited. That base can be of any metal as long as it is welding compatible with the welding wire. Fig. 5 shows a flowchart with each step of this process. Each colour represents a different task or a different software package used. Each box represents an action to be taken, information about a certain entity or even an information end user. The arrows show the direction of information flow.

Fig. 5 'Rapid prototyping using fusion welding' concept

HARDWARE INVOLVED

A graphical description of the rapid prototyping hardware used is shown in Fig. 6. The dotted arrows represent ideal situations and not the real work cell.

Fig. 6 Rapid prototyping work cell hardware

A computer is connected to the robot controller via a serial cable RS 232C and also to a printer. The power source and welding consumables are connected to the welding torch which is mounted on the robot arm. The robot builds the component on a table. This table should ideally be controlled by the robot (broken arrow). The individual components of the system used here are:

An ASEA IRb 2000 robot from ABB. This is not a welding robot but a six degrees of freedom robot with an S3 controller. It only has 64 Kbytes of memory, and this represents a major limitation in the number of programs which can be stored in it.
A turntable could be used, either a stand alone or a robot linked one, although a robot controlled one is advised.
The power source used was a Migatronic BDH 320, although some tests were later on carried out with a Migatronic BDH 550. The welding torch was a Binzel Pushpull torch.
The computer used for the CAD, off-line programming and downloading was a PC with an Intel 80486 microprocessor running at 66 MHz with 16 Mbytes of RAM memory. The hard-disk capacity was 250 Mbytes.
The whole work cell has a fence around it with glass containing an ultra violet (UV) filter to protect the eyes of the operators in the environment. The robot and table alone had another fence with another UV filter. This second fence protected against the physical movements of the robot (shock) and also protected the eyes from the rays. If it was opened a safety circuit would be activated and the whole system would stop working immediately.
The consumables were all the necessary ones for a gas metal arc welding process like wire spool, welding gas and contact tips.

Fig. 7 shows the actual work cell used in this project including all the hardware.

Fig. 7 ‘Rapid prototyping using fusion welding’ work cell

SOFTWARE USED

A graphical description of the rapid prototyping software used is shown in Fig. 8. The software used consisted of the AutoCAD ™ package, the ‘add-on’ developed in this work, a robot simulator package and the compiler/download ABB software to compile and download the robot program to the robot via a serial cable RS 232C.

The main reason for using AutoCAD was its worldwide usage and its being an open system. It is very user friendly and compatible. There are also hundreds of add-on tools available for AutoCAD. AutoCAD has its own programming language which makes it
possible to customise programs according to specific application needs. This language is known as AutoLisp and was the one used to develop the slicing routines.

The robot simulation package used was WorkSpace 3.0. This simulation package is not essential to the process although it was used to check for collisions and timings.
Two different packages can be used to compile and download the robot programs. OLP

3.0 (Off-Line Programming) is a DOS (Disk Operating System) program supplied by ABB which also allows the final robot program to be created directly. The second package is SPORT 1.0 which is a Windows based program developed by Lund University in Sweden which performs more or less the same functions as OLP 3.0. Both programs work with ABB robots only.

TEST SAMPLES

Some components have been chosen to be illustrated and described in this section, although several others were built up with success.

Pint Glass

This component consists of a ‘pint glass’. It took just under half an hour to draw and about 15 minutes to slice, generate the reports and the robot program. It took about an hour to build. It is about 180 mm height and weighs around 3 kg (without the base plate). The width measured in the end varied +/- 0.2 mm. This component achieved a good surface finish, very near geometrical expectations (less than 0.5 mm in height lost). The component described here can be seen in Fig. 9.

Manifolds

A challenge was proposed which consisted in making manifolds for a real car exhaust. Two different sizes were needed (two components each). These were drawn in a total of about 15 minutes (both) and the rest of the preprocessing (slicing, generation of welding parameters, robot program, download to the robot, etc.) took about another 15 minutes. The actual welding took around about 30 minutes each. These were welded to a base plate, but this was then cut away as can be seen in Fig. 10 (two of them are already cut from the base). In only one afternoon the four manifolds were easily made from scratch. The car owner decided to machine just their outside due to aesthetic reasons. The inside was kept as it is because the tiny line marks were used to reduce noise in the exhaust. The larger ones are about 100 mm height and 50 mm radius and the others are about 100 mm height and 35 mm radius. The final width measured varied by +/- 0.2 mm. The components described here can be seen in Fig. 10.

‘Bow Tie’ shape

This sample consists of a 200 mm tall ‘bow tie’ shape. It took about 15 minutes to draw in the CAD system, to slice, to generate the reports and to generate the robot program. It took one and a quarter hours to build. The welding parameters are of extreme importance for the final dimensions, final surface finishing and final quality and these can make the whole difference. The component described here can be seen in Fig. 11.

CAD SYSTEM

The CAD system to be used must fulfil some requirements necessary to the drawing and slicing of the solid. The main requirements for this package are:

solid modelling and/or surface modelling facilities available
facilities for constructive solid geometry
must have its own programming language so that it is possible to ptogramme the slicing routines which will work as an add-on (as in Fig. 2)
facilities for importing/exporting DXF files

shading facilities (not compulsory but convenient).The reason for choosing AutoCAD was mainly to fulfil all these requirements plus its low cost(when compared with other CAD powerful packages such as CATIA, I-DEAS,ComputerVision, etc.), its compatibility with many other packages, its computer platform
being PC based (meaning compatibility with lots of other software) as well as the availability of many add-on tools for different tasks. In addition, it contains a programming language which allows the user to access the graphical information database. This language is AutoLisp and was the one used to make the slicing routines. The add-on (slicing routines) were done with AutoLisp and it has a similar environment to AutoCAD. Menus are available and most of the commands are available through a simple click on the mouse. The main advantages for using it are:

relatively easy to understand
contains proper instructions to work in a CAD environment
full compatibility with AutoCAD
it is an interpreted language rather than a compiled language If other CAD packages are to be used which do not read AutoLisp code, these slicing routines need to be translated to the programming language which the CAD works with.

GEOMETRY LIMITATIONS

This technique cannot be seen as a solution for every shape. It has some limitations which are discussed here. This system is more convenient for hollow shapes than solid shapes because the programming path is easier; there is always a unique start and end and sometimes there is no solution for welding a complete layer without start/stop in between. The fewer start/stop welding instructions the better the finished quality of the component. To make a solid shape the system can start from a metal block saving material and time. Another geometry limitation is the robot working envelope. For larger components a larger robot has to be used or the shape needs to be split into sub parts, building them separately. The part could also be moved away from the robot and welding resumed after a calibration task. Simple components can be made all in one go but more complex shapes could need to be split into parts. Components that contain hanging parts can sometimes be fabricated by using a turn/tilt table. Changing the plane of the table allows the robot to weld in another direction. The turning table must be integrated with the robot and controllable through the robot program otherwise it is worthless and only complicates the process. Difficult access can sometimes be solved by using a welding torch as small as possible or by changing the orientation angle of the torch. For some components the surface finish is important while for others it might be left as it is without compromising the component’s functionality. Different materials provide different surface finish and this should be taken into account when choosing the materials. If machining can be avoided it saves a lot of time, money, effort and the elaboration of complex milling programs. The welding is done by ‘levels’ and for the robot to move from one height to the next it needs a ‘step-up’ movement. Where this movement occurs it leaves a thicker deposition in the component. This occurs because the robot spends slightly more time in the same location thus depositing more material in that place. To avoid this, a spiral technique was introduced in order to reduce that thicker location.

In some other rapid prototyping processes it is possible to make loose parts inside a component without user intervention but that is not possible to do in this metal based rapid prototyping technique. The simple reason is that every weld bead needs to ‘start’ in metal and therefore it is not possible to have loose parts unless these are placed there by the user at some stage. Some of these limitations can be overcome be changing the part design.

ROBOT

A six degrees of freedom (DOF) robot was used for better manoeuvrability (positioning and orientation) of the welding torch, although a three DOF system could be used, but not with all the advantages of the previous one. It is felt that a welding robot should be used in this system because it allows the use of welding instructions into the robot program. This facilitates the setting up of the welding parameters as well as changing them according to programme requirements. The robot program generated is a set of moving instructions with the respective co-ordinates and orientation angles. Each point or location in space uses a certain amount of program size and therefore the more points it has the longer the program gets. These robot programs could and should be optimised in order to reduce size. After slicing the solid model a text format robot program is first generated. Then, it is compiled to a binary format which uses only about one-third of the size of its corresponding text format version. The robot has a memory capacity of 64 kbytes for robot programs (in binary) which means that there is a limit in the component’s size and/or complexity. Before starting a component, the robot was used to locate the starting point (top centre table co-ordinate) for that particular component. This co-ordinate was then input into the CAD drawing to locate the shape within the work cell.

COMPARISON BETWEEN RP AND ROBOT FUSION WELDING

Traditional rapid prototyping systems are:

Are much more expensive (any one costs over £100 000) while this new technique would be at most £50 000.
Use very expensive specially developed materials which solidify in contact with a laser Some examples are wax, photopolymers, thermoplastics (PVC, Nylon, etc.) and ceramics in liquid or powder state. One other process uses a cheaper one (paper). A typical material for a stereolithography machine can cost $300 -$350 per gallon.
Need a dedicated computer The computer is needed to control and guide the whole system and therefore needs to be on. Some other rapid prototyping systems do not slice the solids online but still need the computer to control the lasers during the build up (like stereolithography).
Use expensive CAD programs with expensive hardware to run them.
After choosing the process, there is only one company selling that specific machine, whereas with this new system, almost any industrial robot would do the task.
This type of machine is dedicated to make prototypes while a robot can do other tasks. The robot investment is not only for making prototypes.
Suitable for small components and have small working volumes

Resulting files (SLA or others) are very large files and therefore difficult to transport.
This can be a problem for companies that use a bureaux to make the component.

The slicing is slightly different. While in traditional processes the boundary of the cross section represents the path of the building action (to cut or to solidify), in this new technique the path required is the centre line of that cross section.

A fair comparison cannot be made between bead size of this process and stereolithography because a typical bead size in this process is measured in millimetres (0.5 -2.0 height and
4.0 -12.0 width) while in stereolithography is measured in micrometres.

Although the laser solidifying the material is much faster than the welding deposition, the deposition rate is much higher in the welding process.

CONCLUSIONS

This process started as a rapid prototyping technique, but it was soon discovered it could be used as a manufacturing process for low volume production. The idea was to make prototypes in metal, not only to observe them but also to perform tests on those components. For certain shapes, it is cheaper and faster to make them with this technique rather than using stereolithography or any other traditional rapid prototyping. The investment in a system like this is somewhere near £50 000, while stereolithography equipment can cost up to £100 000. This technique can use any weldable metal; we only need to know the proper welding parameters. A database with the parameters for the most used metals could be created. This slicing method does not read SLA files (from other rapid prototyping processes). To use existing drawing files, these have to be either imported via a DXF format or redrawn in AutoCAD and then sliced with this new technique. Another important aspect to consider in this new technique is that it is possible to use different materials along the component, varying though its structural characteristics. By changing the welding filler wire, one component can be made of several different metals according to the need, as long as they are welding compatibles. This allows a component to have different levels of hardness and strength in different parts. Many industries would prefer this rather than having to have separate parts with different structural characteristics according to design and manufacturing time. Different materials were tried in this work giving different surface finishes proving that surface finishing depends very much on the material used. To properly machine the skin in an average quality component, around 0.5 mm would have to be machined out. If different hardware is to be used with this technique some aspects need consideration. For a different robot, the robot program generator needs some modifications. This will take a couple of hours only, since most of the instructions generated are ‘move’ instructions. For a different CAD program, the slicing routines need to be translated to the language used by the new CAD application. For a different robot simulation package the only requirement is the facility of reading DXF file format to read the slices. As previously said, this technique cannot be used for every kind of shape. Although solid shapes can be made, it is not the purpose of this process to make them. This technique is better for hollow shapes. This process depends very much on the welding parameters used and therefore an in-depth study should be done. In this process the slices are automatically created, the ARLA robot program generated completely automatically and it was not essential to use a robot simulation package to test it, although simulation can be used to save online time. This means that this process is very

automatic with almost no intervention from the user (except for drawing the component in aCAD system).Several components have been made ^3,4,5 with perfectly acceptable quality in surface finishing,mechanical characteristics and dimensions as the case studies describe.

ACKNOWLEDGEMENTS

Many thanks to John Norrish for his support in this project and his expertise in the welding. Very special thanks to John Savill for his strong support in welding all of the components and for solving in an efficient way the practical problems which arose as well as encouraging me to new ideas. A special thank you for my wife is also deserved for her understanding during the difficult periods of this project.

¹ J. Norrish: "Advanced Welding Processes", Institute of Physics Publishing, UK, 1992.

² J. NORRISH: Ogunbiyi B., "An Adaptive Quality Control concept for robotic GMA Welding", 5th International Conference on Comp uter Technology in Welding, Paris, France, 15-16 June 1994, Paper 45.

³ Antonio Fernando Ribeiro and John Norrish, 'Practical case of Rapid Prototyping using Gas Metal Arc Welding’, Fifth International Conference on ‘Computer Technology in Welding’, TWI – The Welding Institute, Printed by Cramptons Printers, 15-16 June 1994, Paris, France, paper 55.

⁴ Antonio Fernando Ribeiro and Prof. John Norrish, ‘Metal Based Rapid Prototyping for More Complex Shapes’, 6^thBiennial International Conference on ‘Computer T echnology in Welding’, TWI – The Welding Institute, Abington Publishing, 9-12 June 1996, Lanaken, Belgium, paper 60.

⁵ Antonio Fernando Ribeiro and Prof. John Norrish, ‘Case Study of Rapid Prototyping using Robot Welding - ‘Square to Round’ shape’, 27^th International Symposium on Industrial Robotics, 6-8 October 1996, Milan, Italy, page 275.

⁶metal casting

Universal manufacturer: RP home

2007-10-12T05:17:00.000-07:00

Two experts from Cornell University are going to commit a veritable revolution in the home workshops around the world. Hod Lipson and Evan Malone have developed a voluminous printer, which can be assembled of the easily accessible parts and in the same time it wont cost as an atomic submarine. The price should be about $2.5 k.

As we know 3d-printers (along with rapid prototyping system) had been invented quite long ago and are developed inside research centers and design studios. But the minimum price of the device with four zeros is surely not conducive to wide distribution. The machine developed by Americans which was named "Fabricator", is a constucotr set of "make by yourself". All drawings, instructions and a control software are available for free from the project site FabAtHome. According to them the mentioned $2.500 are spent exclusively for the purchase of necessary parts. As a result there comes a Microwave oven sized device with a capability to reconstitute CAD models with plastic and other materials. However, the choice of materials is not very rich, because of the construction applies only that you can drive from the syringe and harden quickly.

But according to the developers plans their aim is to create "universal fabrikator" device capable of working with many different materials and to have as a finished product not a separate components, but ready-made operating units. Ideally, such a universal Fabricator must be able to create its own copy. Before that, of course, still very far away, but in any case the appearance of FabAtHome creators have already been compared to the advent of the notorious recruiting Altair 8800, marked a shift in their time of mainframe to personal computers.

Video

User's guide to Rapid Prototyping

2007-10-12T04:42:00.001-07:00

This is an introduction chapter to Todd Grimm's book "User's guide to Rapid Prototyping"

Rapid prototyping is amazing, powerful, and revolutionary. Since the delivery of the first rapid prototyping system, the scope of applications and breadth of use have grown beyond belief. Virtually every industry that designs and manufactures mechanical components has used rapid prototyping. The technology is so pervasive that most people will use at least one product, on a daily basis, to which rapid prototyping has been applied. Rapid prototyping is nearly a billion-dollar industry with more than 30 system vendors that have installed more than 9,500 machines around the globe (Wohlers 2003). With growth in the application of the technology for prototype development, other applications have come to light, namely rapid tooling and rapid manufacturing.

Rapid prototyping is a tool for design, engineering, and manufacturing. As with any tool, there are barriers and obstacles that impede its growth, and there are strengths and weaknesses that limit its use. It is amazing that prototypes can rise from a vat of resin or chamber of powder. It is powerful to produce parts without machining, molding, or casting. However, rapid prototyping is just a tool: an alternative solution to design and manufacturing challenges. The benefits and value of the technology are realized only when it is applied to suitable applications. Determining when to apply rapid prototyping requires an understanding of the technology, the process, and its strengths and weaknesses. Industry leaders believe that this may be the key barrier to the rapid ascent of the technology. Many have concluded that a lack of awareness, understanding, and appreciation of rapid prototyping are critical barriers to its adoption and growth. The goal of this introduction is to assist companies and individuals in assessing the merits of rapid prototyping and developing a full understanding of this unique and powerful tool. With this description, each can make an informed, personal decision regarding the applicability or necessity of rapid prototyping in the product development process.

CREATING UNDERSTANDING AND AWARENESS

Magazine articles, conferences, technical articles, books, and even television news programs have featured and discussed rapid prototyping. Nearly every trade show that serves the design and manufacturing communities has a rapid prototyping presence. There are thousands of web pages available on the Internet that promote and discuss the technology. Yet, there continues to be a scarcity of information that offers detailed analysis, review, and comparison. Much of the publicly available information addresses the obvious advantages of rapid prototyping, focusing on the remarkable ability to grow parts from digital data. Much of what remains focuses on the latest systems and materials developments, often resulting from vendor-issued promotional materials. What is missing is information that details the true experiences of rapid prototyping users. Without an accurate account of both the advantages and limitations, from a user’s perspective, the knowledge gap impedes an increase in awareness and understanding. Gathering information to develop an understanding is especially difficult for those who are new to the rapid prototyping industry. As an introduction to rapid prototyping, the discussion of the technology targets the majority of those in industry, those who have yet to apply it. Yet, this is not a light review of the technology. The detailed accounts and user insights offer a deep appreciation for the technology and the process. Even experienced rapid prototyping users will find valuable insight and information. To fill the knowledge gap, this introduction to rapid prototyping details the process, individual technologies, applications, strengths, and limitations. It also offers a comparison of rapid prototyping technologies with processes like machining.

WHAT IS RAPID PROTOTYPING?

One benefit of a rapid prototype is that it improves communication. However, the technology is often a source of miscommunication and misunderstanding. There are numerous terms for rapid prototyping, including: freeform fabrication, solid freeform fabrication, autofab, automated freeform fabrication, digital fabrication, 3D printing, laser prototyping, layer-based manufacturing, additive manufacturing, and solid imaging. The multitude of terms and definitions can confuse a discussion or description of rapid prototyping. Equally confusing is that a simple term like 3D printing has multiple definitions. Some in the rapid prototyping industry use the term 3D printing to characterize all varieties of rapid prototyping technology. Others apply the term to a specific class of rapid prototyping systems. With the great disparity in definitions and terms, it is critical that there is an agreement and understanding in any discussion of rapid prototyping. Without this agreement, miscommunication is likely. This is Not a Book About Prototyping Within the design and manufacturing communities, other factors contribute to the confusion. There is disagreement on the technologies that should be included under the umbrella of rapid prototyping. Many suppliers of technologies and materials for processes as varied as machining and molding promote their offerings as rapid prototyping. While each truly prototypes rapidly, they are subtractive or formative processes. To include them in the discussion that ensues would require an introduction to prototyping, a topic that is much too broad for a single book. This is a Book on Rapid Prototyping Instead, this is a book dedicated to rapid prototyping. This book is about additive processes that eliminate machining, tooling, molding, casting, and fabrication. The election to address only additive technologies is not an indication that other processes are not rapid. As will be illustrated, rapid prototyping may be a slower process or a weaker solution for a project. Combined with the extensive information and first-hand experience available for other, conventional processes, this detailed account of rapid prototyping promotes the ability to select the best technology and apply it wisely. The technology decision is personal and unique. In some cases, rapid prototyping will be the best. However, as will be shown, in most situations the selection of the best tool will not be obvious. With ample amounts of crossover, both rapid prototyping and the competitive technologies are likely to serve a user’s needs. These conventional processes are often rapid prototyping solutions; however, they are not additive rapid prototyping solutions and, therefore, they will not be discussed.

DETAILED TECHNOLOGY DESCRIPTION

This introduction to rapid prototyping will cover, in detail, all aspects that are important for a clear understanding and appreciation of the technology. Chapter 2 begins with an overview of the technology, its applications, and benefits. In this overview, rapid prototyping is clearly defined. While rapid prototyping can be a push button, one-hour process, much more goes into most prototypes. To develop an understanding and to build a foundation of information on which to build, Chapter 3 details the rapid prototyping process. Through this description, there will be a greater appreciation for what it takes to successfully build rapid prototypes and the information required for making good technology decisions. For further clarification, classes of rapid prototyping are presented in Chapter 4. While the rapid prototyping industry lacks consensus, this proposed classification system helps to distinguish the differences between a $30,000 and an $800,000 system. Although the methodologies and output are similar, there is a great variance in operational demands, user control, and final results. Chapter 5 discusses applications and benefits. As indicated, rapid prototyping is more than a prototyping tool. Its applications cover the full spectrum of design and engineering and extend to applications in manufacturing. Additionally, there are examples of applications outside of the confines of design and manufacturing. From these examples, new ideas and unique, innovative solutions may come to mind. Since some include machining in the rapid prototyping application set, and since machining can be as fast or faster, a detailed comparison of rapid prototyping and computer numerical control (CNC) machining is provided in Chapter 6. With this head-to-head comparison, it will be possible to determine when and how to apply each tool. Using four leading technologies, Chapter 7 provides a head-to-head comparison of rapid prototyping systems. Containing information known only to rapid prototyping users, this comparison reveals key considerations of the technologies, exposes some little known truths, and eliminates common misperceptions. For those who find that rapid prototyping could be valuable, the path through justification, evaluation, and implementation may be challenging. Chapters 8 and 9 are guides for the selection and implementation process. Although the focus is on prototyping, an introduction to rapid prototyping would be incomplete without a discussion of rapid tooling and rapid manufacturing. These applications are intertwined with rapid prototyping, and it would be inappropriate to exclude them. In addition, many believe that these two applications may be the areas of significant growth in the coming years. Chapter 10 addresses both rapid tooling and rapid manufacturing. To complete the introduction to rapid prototyping, Chapter 11 summarizes the key aspects of rapid prototyping and forecasts the role that the technology will play in the future. Whether or not the decision is to use rapid prototyping, one must keep abreast of the coming changes. Appendices A through C offer supporting information. Appendix A provides user case studies that show the realworld benefits of rapid prototyping. Appendix B lists useful resources that may be helpful in the further evaluation of the technology. And finally, a glossary of terms is provided in Appendix C.

SHADES OF GRAY

There is not an answer that is right for everyone. The benefits of rapid prototyping are always in question until the question is asked in the context of specific needs and goals. If rapid prototyping is a viable tool, the answer to the question of which technology is best will be unique, personal, and individual. Therefore, the information is not delivered with definitive statements. Instead, the technology is discussed in a way that allows the reader to develop his or her own answers. This book has something for everyone. For those who believe in rapid prototyping, there is information that will support their convictions. For those who want to prove that rapid prototyping is an inappropriate solution, there is plenty of justification. And for those who simply want to determine the right answer, there is plenty of information to aid in the decision-making process. How can all of these desires be satisfied at once? It is simple. This journey through rapid prototyping offers no definitive statements, and in many cases, it is delivered in a way that invites more questions. The information offered carries an overriding principle that the answer to each question is ‘‘it depends.’’ The strengths and weaknesses, applications and benefits, and evaluation and implementation of rapid prototyping are unique to each part, product, program, and company. Therefore, the answer to every question will be ‘‘it depends.’’ The answers can only be determined when the information on rapid prototyping is combined with the specific and unique circumstances within each company and for each project.

A TOOL FOR CHANGE

Faced with economic challenges and global competition, the way business is done is changing. Organizations around the globe need to drive costs out of the process and product while enhancing quality and reducing time to market. Those who shoulder the burden of these requirements and initiatives find themselves with more work, fewer resources, and crushing deadlines. To cope or excel in this environment, the way business is done has to change. Although this change will come in many forms and take years to develop, two key elements are collaboration and innovation. Design engineering and manufacturing engineering need to eliminate the barriers between the departments. Rather than ‘‘throwing a design over the wall,’’ design and manufacturing should communicate early in the process. This communication will produce a better product at less cost and in less time. To innovate, change is required, and this change demands that nothing is taken for granted and that no process is sacred. New methods, processes, and procedures are required in the highly competitive business environment. Rapid prototyping may be the tool for change. To realize its full potential, rapid prototyping should be adopted by all functions within an organization. If implemented, it should not be designated as merely a design tool. Manufacturing needs to find ways to benefit from the technology, and it should demand access to this tool. This is also true for all other departments: operations, sales, marketing, and even executive management. When adopted throughout the organization, rapid prototyping can be a catalyst to powerful and lasting change.

INFORMED DECISIONS

The rapid prototyping industry has achieved much since its inception. There have been major advances since the 1987 introduction of stereolithography. Yet, there is room for growth and a need for further advancement. Many of the obstacles that rapid prototyping faces are not unique. As with any new technology, there is a resistance to change and a reluctance to work through the challenges of a developing technology. However, there are other factors that are unique to this industry. Since rapid prototyping requires 3D digital definition of the part, its growth rate is the same as that of CAD solid modeling, an application that is far from being used by the majority of design professionals. Additionally, rapid prototyping has been burdened with a negative perception that the parts are ‘‘brittle.’’ While this was true many years ago, this is no longer an appropriate generalization. Yet, many use the belief that rapid prototypes are brittle to justify not evaluating or using the technology. Since it continues to be a tool for the minority, rapid prototyping may not pose a competitive threat to those who do not use it. However, many companies that have implemented the technology have discovered powerful advantages in applications that range from product development to manufacturing to sales and marketing. The decision is yours. This introduction to rapid prototyping offers no answers. Instead, it offers information to assist in making an informed decision.

REFERENCE

Wohlers, T. 2003. Wohlers Report 2003: Rapid Prototyping and Tooling State of the Industry Annual Worldwide Progress Report. Fort Collins, CO: Wohlers Associates, Inc.