3D PRINTech

Scientists 3D Print Functioning Human Heart | University of Minnesota | ...

2020-07-23T20:05:00.001+08:00

Expectations vs Reality: If Every Home Had a 3D Printer?

2020-07-01T23:33:00.001+08:00

On average, over 8,000 people die each year in the U.S. because they can't get an organ transplant. But, what if we could actually rebuild our failing organs?

That possibility of creating anything you want from home could be just around the corner with a 3D printer. Right now, our bodies face the possibility of breaking down. But, what if we could wipe out that risk by creating medical devices that can help us, like hearing aids, pacemakers, or new dentures. Imagine if we could actually 3D bioprint our vital organs.

3D printing, also known as Additive Manufacturing is a manufacturing process that takes a digital file known as computer-aided design or CAD and brings that 3D model to life. The most common 3D printing process is known as it works the same way as your standard ink-jet printer, except instead of ink, it uses thermoplastic material, which gets pushed through a nozzle, like a hot glue gun. A spool of filament is loaded into a printer and gets heated up. It keeps layering 2D cross-sections in thin horizontal lines that sit on one another until you end up with a solid three-dimensional object. The 3D Printing materials can also be in the form of liquid (for SLA and MJ processes) or powder form (for SLS/SLM, and DED process). It's the creation of living tissues, such as blood vessels, bone, heart cells, skin cells, or cartilage. Imagine what 3D bioprinting could do for organ donations.

In 2019, in the U.S., there were more than 100,000 people on waiting lists for organ transplants. The average wait time for a kidney is between three and five years. Scientists hope that someday soon they will be able to print a kidney. All they'll require is a sample of your blood, to create one in six to eight weeks. Imagine the lives this would save.

Advances in this biotechnology would allow us to eliminate testing on animals. Instead, we could use three-dimensional living tissue, which would be more accurate when conducting medical studies. Dying of old age could be eliminated. When certain parts of your body start to deteriorate, you would swap them out. Lungs, heart, liver, whatever you desire. Just replace them every 20 years, or sooner if needed, like upgrading to the newest version of an iPhone. You wake up in the morning, log in to your computer and type pancakes and call a 3D Printing service company. Minutes later, your breakfast is printed and ready.

Now, what should I wear today? A new shirt, it is! Next, shoes. Perfect. Then, you drive to work in your 3D printed car.

3D printing would allow us to create anything we dream of a one-stop Amazon shop, right under your own roof. In the U.S. alone, there are approximately and in 2018, two out of every 1,000 homes had a 3D printer. It will be years before 3D printing is feasible in the average home. But, imagine if they become affordable for the average consumer. Retailers could be removed from the economic equation, with consumers choosing to print virtually anything they want. The 3D printing industry is rapidly growing, despite the fact that less than 1% of global manufacturers currently use this technology.

In 2019, the market grew to over $10.4 billion, crossing the double-digit billion thresholds for the first time in its nearly 40-year history. The 3D printing market is set to double in size every three years, with an annual growth forecasted between 3D printing could create less need for transportation and distribution, resulting in a smaller carbon footprint.

Finally, a well-deserved break for Mother Earth. Well, maybe not. 3D printing currently relies primarily on plastics that produce toxic by-products and fumes. It also requires a lot of energy. Some 3D printing processes call for 50 to 100 times more electricity than traditional injection molding methods to make an object of equal weight. What's to stop someone from 3D printing illegal drugs, weapons, or bootleg products. Governments would have to impose restrictions on a tool that could provide endless possibilities. But before you get too excited, the reality of every home having a 3D printer as a common household item is doubtful.

The cost of materials is still expensive, and the skill required to make and assemble finished objects is high. Similar to the prediction of everyone having flying cars, we likely have a long road ahead of us.

What do you think about the 3D printing revolution? Let us know in a comment below or on our Facebook page!

Ultrasonic Waves for Analyzing Residual Stresses in Additive Manufactured Metal Parts

2020-06-28T15:36:00.002+08:00

This Additive Manufacturing (AM) process produces metal parts layer by layer using a high energy laser beam to fuse metal powder particles. When each layer is complete, the build platform moves downward by the thickness of one layer, and a new powder layer is spread on the previous layer.

While this process is able to produce quality parts and components, residual stress is a major problem during the fabrication process. That's because large temperature changes near the last melt spot - rapid heating and cooling - and the repetition of this process result in localized expansion and contraction, factors that cause residual stress.

Residual stress (RS)

Residual stresses are self-equilibrating stresses which remain in the part after its manufacture even without supplementary thermal gradient and external forces. These stresses arise from misfits in the shape of parts of both different regions and different phases within a part, or even because of local variations in elastic constants, or thermal and mechanical properties. RS can result in several undesirable consequences on the part's properties, such as poor fatigue resistance, critical failure during operation, lower chemical resistance, lower magnetization, lower resistance to deformation, and diminished static and dynamic strength.

RS can be classified according to the length scale on which they occur:

Type I: Macro RS, which equilibrate over large distances and deform the part if boundary conditions are changed.

Type II: Micro RS, that occur over the grain scale because of the formation of different phases in the structure. They are frequently observed in a polycrystalline material because of the different grain orientation and the anisotropy of a crystal structure.

Type III: Micro RS inside a grain (over atomic dimensions), which occur because of defects such as dislocations, vacancies, or alien atoms distorting the crystal lattice in the crystal structure.

Ultrasonic Waves

Ultrasonic waves (UW) testing uses mechanical waves, which are oscillations of material particles that need a material medium to propagate. These waves are used in many fields of application: medical, mechanical structural measurement (NDT), sensors, sonars, and weapons. Typically, UW has a frequency higher than 20 kHz, corresponding to the upper limit of the human hearing range (high pitch). Its utilization in NDT has several advantages, such as good accuracy, high speed, reliability, repeatability, affordability, and capability to use in several environments such as liquids. Also, it is non-destructive and does not require direct contact with the part being tested, which makes it suitable for in-situ monitoring systems in AM. Finally, there is no limitation in terms of the type of material being tested or its geometric complexity (thin films or large components), and it is minimally influenced by temperature.

Analyzing Residual Stresses Ultrasonic Waves

Residual Stress measurement techniques.

Researchers from the Czech Republic and Brazil worked together to focus on the ultrasonic testing used for stress analysis of 3d printed metal parts and published a research article titled, “Residual stress analysis of additive manufacturing of metallic parts using ultrasonic waves: State of the art review”.

Process variables affecting the residual stresses

The authors have highlighted the potential of ultrasonic testing (UT) for measuring RS during and after construction. The use of ultrasonics has a long history when testing and characterizing materials, and may be very valuable when looking for problems such as deformation, delamination, or structural damage. As a non-destructive test method, UT involves sending short-pulse ultrasound to the material under test to detect internal defects.

The author proposes many benefits of the technology, including accuracy, speed, repeatability, and affordability, a large number of materials can be analyzed, and even this technology can be integrated with an automatic monitoring system and a 3D Printing system. However, it is more suitable for measuring RS in the whole part rather than in a specific area.

A typical configuration of the ultrasonic method using spatially resolved acoustic spectroscopy

Although the other RS measuring methods such as hole drilling (HD) and X-ray diffraction are still most commonly used measurement methods - provide accuracy and reliability for industrial applications, but many limitations are there such as small sample size, rough surfaces, destructive testing with numerous errors.

The author highlights many research advances that are currently devoted to the use of UT for RS testing, including Spatially Resolved Acoustic Spectroscopy (SRAS), a technique that uses two lasers to inspect the surface and near-subsurface features, and various other laser-based methods. They suggested that although most machines today rely on X -rays, infrared cameras, and high-resolution cameras, these UT technologies can be incorporated into metal additive manufacturing systems to perform in-situ monitoring of parts.

Challenges

The most remarkable challenge is that the optimization of the link between UT apparatus and the AM hardware is required. The complexity of AM parts brings another challenge to UT, since it is limited to simple geometries. Another limitation of using ultrasonics as a quality control system is the complex geometries of additive manufacturing parts, because UT is limited to simple geometries.

Commercial Systems

Existing in-situ monitoring tools for commercial systems are quickly evolving: EOSTATE Meltpool is able to monitor the entire building process through four separate and independent modules (Base, PowderBed, Meltpool, Exposure OT), increasing control on machine parameters and part quality. Besides, in a recent development with MTU Aero, a promising contact UT device was created including high spatial resolution (40 μm) and capability to measure porosities. Furthermore, ARCAMLayerQam allows us to monitor porosity and defects up to 100 μm overall build chamber regarding before and after each layer. Another interesting tool is ARCAM xQam, an X-ray automated detector employed to calibrate the electron beam of EBM machines and it has the potential to be used in material characterization.

What do you think about using ultrasonic waves for analysis of 3D Printed parts? Let us know in a comment below or on our Facebook page!

Advanced Materials for Additive Manufacturing: Architected Polymer Foams via Direct Bubble Writing

2020-06-26T19:11:00.001+08:00

The polymer foam material refers to a microporous material based on a polymer (plastic, rubber, elastomer, or natural polymer material) with numerous bubbles inside, and can also be regarded as a composite material using gas as a filler. At present, polymer foam materials are mainly prepared by directly expanding and foaming the resin with a foaming agent. How to accurately control the micro-cell shape, the appearance and macro-foam structure are still a difficult problem.

In order to solve some problems in the process of preparing polymer foam by direct expansion foaming method, Professor Jennifer A. Lewis and co-workers describe the fabrication of architected polymer foams by "direct bubble writing". In this process, bubbles are ejected into the air, deposited onto a substrate, and then photopolymerized with UV light, and open-and-closed-cell foams with locally graded densities can be printed into 3D objects such as 3D lattices, shells, and out-of-plane pillars.

The researchers designed a special nozzle with a double-layer structure inside and outside: the inner tube deposits a polymer precursor solution containing polymer monomers, initiators and surfactants, the outer tube supplies gas, and the two are mixed at the nozzle mouth to form a writeable bubble "ink". A single bubble drops from the nozzle onto the substrate to accumulate. After the polymerization is initiated by ultraviolet light, the bubbles are bonded to form a macro-foam block. According to the theoretical and experimental results, the ink dropping flow rate and gas pressure are the key parameters for preparing different microscopic cell morphologies.

Compared with traditional foam preparation methods, direct writing has several advantages. The most important benefit is the controlled cell morphology and distribution. Precisely formulating cell morphology and preparing foam with excellent performance is the biggest innovation of the direct writing foaming method. The cell morphology mainly includes three elements: open/closed cell structure, pore size, and distribution. The researcher controls the structure of the open and closed cells by the type of gas: when using oxygen with polymerization inhibition as a gas, it can stop or delay the polymerization of monomers that contact the oxygen surface and have a depth of about 40µm, so that the cell wall becomes thin and becomes an open-cell foam. When inert nitrogen is used as the gas source, polymerization normally occurs, and the cell walls are thick, forming closed-cell foam. The pore size and distribution are adjusted by air pressure. The cell diameter obtained at lower air pressure is approximately 0.5 mm, and the distribution is very uniform; when the air pressure is increased, the obtained cell pore diameter is between 0.3-0.7 mm, and the distribution is also non-uniform.

Open and closed-cell foam preparation process

Another advantage is the preparation of gradient foam with variable mechanical properties. During the continuous 3D writing process, the process parameters are adjusted intermittently to change the density and modulus of the local foam, so that the resulting foam exhibits a gradient in shape, thickness, and distribution. Gradient Foams with variable mechanical properties are difficult to produce by conventional foaming methods.

The elastic foam materials are mainly used for the production of protective helmets, personalized orthoses, high-performance shoes, and other various application products.

This research results have shown that the direct writing method can accurately control the micro-cell morphology and macro-foam structure, program the mechanical properties of the foam, and can also easily give new functions to the foam. 3D printing is capable to make uniform and gradient foams, which will revolutionize the foam industry and produce products that are more comfortable, safer, lighter and can be personalized.

What do you think about 3D printing of polymer foams? Let us know in a comment below or on our Facebook page!

Digital revolution in the kitchen: How 3D printers will create your next meal

2020-06-26T01:23:00.005+08:00

The 3D printing of food has been an evolving method of food production over recent years, and has allowed designers to combine their 3D digital design knowledge with food to produce shapes, textures, tastes, and forms that were previously found too challenging to create by hand, all whilst still being edible.

3D food printing is able to make dishes from different pastes and materials, so it seems we are getting closer to the science-fiction concept. However, this time we are not in a sci-fi movie! Just look at the innovations already offered by different manufacturers who have all food printers that can make chocolate, pasta, sugar, and even more dishes: the possibilities are almost unlimited.

Current 3D food printers are designed to deposit small layers of material — think of a frosting dispenser except the ingredients are squeezed out, layer by layer, by a robotic arm. The latest models of 3D food printers are more complex and detailed. Examples of such devices are those used in the candy and baking industries. The 3D printer ChefJet crystallizes small layers of sugar into several geometric configurations, while Choc-Edge dispenses chocolate from syringes into intricate, delectable designs. Some advanced printers, such as The Foodini, use fresh ingredients filled in stainless steel containers to make different types of foods like stuffed pasta, pizza, brownies, and quiche. There’s a fair amount of companies that are getting involved with this new way of producing food. Some of the key players include TNO (innovation for life), Philips, Electrolux, Barilla, Nestle, NASA, Hershey’s, Modern Meadow, Choc Edge, 3D Systems, Natural Machines, ZMorph, and FabHome, etc.

You will have more customizable food experiences
source: sushi singularity

3D printing food will open the doors to a new level of creativity

Printers could create nutrient-rich and environmentally-friendly food products and even help address hunger problems in areas that need access to quality and affordable ingredients. The technology also creates an opportunity for food customization. Maybe in the future, you could buy your own customized 3D the printed chocolate bar just as easily as you can buy your favorite snack at the corner shop, or even create your own from your own machine at home! That’s food for thought.

According to a 2018 Research Nester report, the 3D food printing market is expected to expand at a compound annual the growth rate of 50 percent during the period 2017-2024 and is expected to reach $400 million by 2024. The research suggests that market growth is driven by two main factors: an increased desire for customization and applications from the healthcare sector.

3D Culinary Printing by 3D Systems

Despite the many exciting possibilities of 3D food printing technology, the industry still has challenges to overcome. To print food using the current 3D printer, users must convert their ingredients into a paste. It is the only way the device can manipulate the ingredients. Furthermore, most printers available today are designed for dry and shelf-stable materials, excluding most dairy and protein products that spoil faster. That means every ingredient must be dry otherwise users will have to worry that something could spoil. It is a matter of food safety. And while there is the hype about 3D printed food and the technology in general, it is important to measure expectations. In simple terms, we must continue to consider the health, environmental, and social impacts of food printing.

What do you think about 3D printing of your next meal? Let us know in a comment below or on our Facebook page!