The second is specific to creating molds. This part is vitally important to understanding the main driver of cost in a plastics project.

Finally, if you’re feeling really geeky, you can check out the Wikipedia article dedicated to discussing Injection Molding here : https://en.wikipedia.org/wiki/Injection_moulding

So, now that we have that out of the way, let’s get into the nitty gritty.

There are quite a few variables that go into the mix to get a satisfactory results and good price/performance.

We’re going to discuss this in direct relation to the China market and what is common here. Other parts of the world will have some different variations, but they should generally hold. I’m also going to discuss prices in multipliers from a base as much of our pricing data is confidential with our suppliers.

• Design
• Mold Base
• Mold Insert
• Plastics
• Mold production, assembly test and loading
• MOQ's

• Design

  This one (rightfully) starts at the top. The simplicity or complexity level of your molding design will directly impact its cost and manufacturability. Intricacies will increase the cost and complexity tremendously. It’s nice to have a cool shape or effect in the plastics. However, that can directly impact the way the mold tooling will be created, drive higher costs and, potentially, decrease yield levels to a point where it’s not economical to produce the product. Simplicity is the name of the game here.

  A side note about design and impact on assembly. We find that the final assembly can be very challenging if the designs have not been adequately tested in the lab. We recommend a good 3D print of your components before sending for manufacturing. It’s much less costly to spot assembly issues early with a good 3D printed version, so take the time to take advantage of being in second decade of the 21st century and print up some cases!

• Mold Base

  There are two types of mold base with different types of materials. There are “standard mold bases” that are, just like they sound, the ones that conform to a set of standards. They are generally a similar size and are not always the best option if you either have a very large or very small part to mold. There are also custom mold bases. The main driver of cost is where they are sourced from as well as the materials used. Locally sourced Steel #45 mold bases are the least expensive. The most dominant maker of premium mold bases in East Asia is LKM (Lung Kee) and these are generally about 2-3x more expensive than the locally sourced mold bases.

  Custom mold bases will vary wildly in price since they are not common, but there are some reasons why these may be a better idea. When the parts are smaller, for example, a custom mold base may be better. In this case, it is possible that a custom mold base may be a more economical way to go since the amount of materials needed may be less than a standard mold. It pays to find a professional that can help to guide this decision process.

• Mold Insert

  This is where the most variation comes into play. The cost of the mold inserts will be directly related to the materials used and the size of the parts that will be molded. Molds are priced per kilogram. The main difference with the materials is the lifespan of the mold. The stronger the materials, the longer the mold insert will last. In the Chinese market, there is also a significant difference between imported materials versus domestic materials. In general, the imported mold insert materials come from Japan, Germany and Korea with Japan being the most common source. We’ve put together a handy table below to compare the materials (below). Steel #45 is used as the baseline.

  Materials	Domestic Pricing (per kg)	Imported Pricing (per kg)	Lifespan (# of shots)
  Steel#45/#50	1-2x	N/A	50,000-100,000
  P20	3x-5x	N/A	300,000-500,000
  718 Steel	5x-7x	15x	>500,000
  738 Steel	8x-10x	15x	>500,000
  NAK80	15x-18x	23x	>800,000

  As you can see, the variation in price is huge. However, since the insert costs are one of the highest costs in this process, it’s good to make sure that you know how many of these parts are going to be made. Also worth noting is that it’s not common to use steel #45 for these inserts because the resulting plastic tends to be rough. There may be a temptation to “go cheap” with a lower quality material, but this is where planning ahead can save a lot of money in the long run.

• Plastics

  Once all of the tooling is done, then there is the question of plastics. There are many different types of plastics out there. There are general, industrial and medical grade plastics (among others). There are various vendors for each with wildly varying prices. However, compared to the tooling costs, the plastics tend to drive less cost than other parts of the process. In China, the most common plastics come from Kingfa (domestic) and Chimei (Taiwan). The pricing is competitive. There are also foreign manufacturers such as Bayer/Covestro that are readily available. A word of caution, however. There are lots of problems with counterfeiting when it comes to “branded” plastics. It pays huge dividends to make sure you have a trusted supplier, manufacturing partner and/or EMS partner. NexPCB maintains good relationships with many of these trusted suppliers to ensure we get the proper materials.

  There is one more element that gets precious little airtime with plastics: colors. Many new products will offer a variety of colors for their customers to select from. Be careful, here. Plastic colors can be made one of two ways. The first way is to buy a pre-colored plastic that is either a standard or a custom color. The second way is to mix colorant in at production to produce a color. The first way is very precise and the second way can be highly variable from one run to the next. Why would you not choose the first option you may ask? MOQ’s…

  For colored plastics, the MOQ’s can be very high. Some companies want MOQ’s as high as 750kg or more for each color. Plastics are light, so some quick math on a product that only needs 50g of plastic per shot tells you that this is a LOT for smaller projects. If you offer 5 colors, then you’re looking at a minimum outlay of 3750 kg of plastics. For some projects, this isn’t a big deal. But, for makers that are just starting out, and extra $30k in cost just for plastics may blow a hole in their budget.

  That leaves mixing. This is a fairly economical route since the price for colorant beads isn’t too high and the MOQ’s are generally a 10kg bag or two. The challenge is precision. If you’re planning to ramp up production and want the colors to match from one batch to the next, it will be a challenge. The colors will generally be close, but they won’t exactly match. This may bother some people, but others don’t sweat it. Just keep the caveat in mind when you tell your Kickstarter campaign that they can have a rainbow of colors to choose from…

• Mold production, assembly test and loading

  Different production processes will vary the cost and the amount of time needed for each part. This depends on the design abilities and the facilities of the factory. Some plants specialize in automotive plastics while other focus more on industrial plastics. If you ask a plant that specializes in something that doesn’t fit the profile of the product you want to produce, it’s likely that you’ll get an answer that is overpriced. This is generally because the plants will add an extra risk premium in when producing projects that are outside of their core competence. It’s best to choose plastics factories that are aligned with what the project requires (as much as that’s possible).

  Speaking of risk, the matter of testing also comes up regularly. The pricing for a production run will vary based on the number of tests that the factory will run to confirm that the final product is correct. Some some factories (in China) support molding tests up to three times whereas others do not specify how many times they will test. There is different risk levels to the supplier, so they may run more tests for verification. We generally recommend a minimum of two tests to be run per production.

• MOQ's

  Obviously, since we’re talking about manufacturing, the minimum order and lead time can drastically impact the cost of the production. Higher values for both (respectively) lead to lower costs. There are some specific topics that we’ve found are the easiest to overlook when it comes to MOQ’s. These generally are:

  • Colors (discussed earlier)
  • Factory imposed MOQ’s(some factories will do small runs in between larger ones, so this affects lead-times)
  • Plastic material selections (some plastics require higher purchase amounts than others, so make sure to ask)

Whew.. That was a lot.. Now you can understand why I get so nervous when a customer talks about their plastics work like it’s just a box to cover their stuff. It’s not quite so easy. There are a lot of variables to keep in mind. 

If you’re confused by all of this, NexPCB would be happy to help you out. We have relationships with many trusted suppliers in China that can help you with the plastics part of your turnkey project. We’re always happy to help customers that need a fully assembled solution. Feel free to reach out to sales@nexpcb.com and one of our friendly folks will help to demystify these challenges for you! 

If you have a project that you'd like NexPCB to assist with, you can fill out our handy project request form here and we'll review your technical details as well as give you a competitive price. 

We are excited to be participating in Autodesk's inaugural developer’s conference. With the release of the new Forge Platform there are APIs that will enable you to tap into Autodesk technology with your existing platforms and solutions.
Whether you are just curious, looking for a new solution, or want to see how to leverage the cloud for your next project. We are willing to share with you how to facilitate your innovation and scale up your Know-How for greater success.
Join us and over a thousand developers from 700+ companies in San Francisco on June 15 - 16 to get inspired by the challenges and opportunities facing designers, engineers, and makers of the world.
Register using code [NexpcbForge] or REGISTER NOW to get 30% off of your registration.

Keynote speakers are pushing the boundaries of the Future of Making Things

What is serendipity? Wikipedia says it is a "fortunate happenstance" or "pleasant surprise".  For us, attending Events and Conferences can be such an occasion for serendipity since you always can come across some valuable and interesting ideas, products or persons. 

At the beginning of 2016, we are busy planning which conferences and events NexPCB will attend. You know, it is not exaggerating that there is tons of tech events and conferences with tons of goals all over the world. And we are lucky to find a blog created by Loggly, who has made a comprehensive list of DevOps events and conferences related gatherings in one place and help DevOps lovers a lot. It inspires us so much because we also cannot find such a comprehensive list of Hardware related events, and we believe we are not alone!

So we started compiling the information in a doc according to Loggly's way, and we're sharing it with you now to help you make your event schedule for the year!

If you are hardware makers, businessmen, manufacturers or tech lovers, here you will find proper events to attend coming up 2016.

Besides the below list, we also compile the list of hardware incubators, makerspaces and hardware meetups. Keep attention to these groups as they will held activities  frequently, which may benefit you a lot!

See you at the events!

 Download the below sheet:PDF format>> 

Do you have an event you’d like to add to this 2016 list of Hardware events and conferences? Drop us a note on Twitter:@NexPCB

We love meetups, where we share our stories, exchange ideas and meet interesting persons around a common theme. Compared to the number of others like software, it doesn't seem to be a very large number of meetups for hardware startups.

So here we select a list of popular hardware meetups in NYC and CA, which will be updated as we hope to refer to you all the worth-going activities around the world.

Besides the below list, we also compile the list of hardware incubators, makerspaces and 2016 best hardware events and tech conferences. Keep attention to them as there you can also find some worth-going activities.

See you at the activities!!

Do you have any meetup activities you’d like to add to this list? Drop us a note on Twitter: @NexPCB.

Hey friends!
As is known to us all, makerspaces now are popping up all over the the world, which benefit our makers quite a lot.
Here is a list of the makerspaces, which will be updated in time, If you have any additions to the list, please let us know.

USA

New York

1. NYC Resistors 
NYC Resistors is a well-established makerspace based in downtown Brooklyn. Co-founded by a group of tech professionals including 3D printer guru Bre Pettis, the space is equipped with a laser cutter, 3D printer, hand tools, sewing machines and stocks of DIY kits and components. Walk-ins are welcome on Monday and Thursday nights or at the regular study groups on Micro-controllers and Web Development. Daily classes are also run on topics such as soldering and programming ($50-125). Members enjoy full use of the space for $75/month.
2. Alpha One Labs
Founded in July 2009, Alpha One Labs aims to provide a‘fun, tool rich space for users of all ages and interests to work on projects together’. The space holds weekly meetings every Tuesday at 7pm where anyone can bring along projects they’re working on and brainstorm collaborations. It also hosts regular events on programming, robotics and lock picking as well as weekly‘Solder Sundays’ at 1pm. Membership costs $40/month and gets you 24 hour access to the workshop, class discounts and a free t-shirt.
3. Hack Manhattan
The only Manhattan-based space on the list, Hack Manhattan is right off Union Square and plays host to a variety of meetings, classes and talks by leading tech companies. Learn how to design a circuit board, operate a 3D printer or experiment with microcontrollers while meeting fellow enthusiasts for tech, science and the arts. The space boasts a 3D printer, machine shop with lathe, mini-mill and drill press, sewing machines and soldering irons. New faces are welcome every Tuesday night to drop-in and chat about creative projects.
4. Genspace
Pushing the bounds of what it means to be a makerspace, Genspace brings together amateur science enthusiasts to work on biotech-related projects in a fully equipped community laboratory. For absolute beginners, classes are offered in DIY Neuroscience, Synthetic Biology and DNA barcoding by members with doctorates while hardcore enthusiasts can opt for the week-long Biohacker Boot Camp. If you’re wondering what biotech is, you might want to start out at one of Genspace's regular education events; recent visitors have explored their microbial biome, learnt bioinformatics and created slime mold art pieces.
5. Gowanus Studio
The Gowanus Studio Space (GSS) offers a home to budding designers, artists and craftspeople. Located along the Gowanus Canal in Brooklyn, it houses a large arts workshop, private studios and an exhibition space. Members enjoy access to a drill press, lathe and saws in the woodshop while in the print shop they can get their hands on etching and lithography presses, silkscreen printing and glass tables. Recent classes have included textile printing, papermaking and photolithography ($40-100). Members have full access to the space for $95/month.
6.Fab Cat Fab Lab
Tucked away next to a Washington Square Park jazz bar, the digital fab lab has an open-source ethos and open houses every Tuesday evening. It is a bit hard to find, but once you do, you'll be delighted by the energy of Renee Cruz who has been crafting the vision of the space over the past year (she also runs a really cool education program in Fat Cat Jazz Club for youth during the daytime. Ask her about it!) At Fat Cat Fab Lab, you can learn how to use a laser cutter, which is a precision machine that cuts wood, metal, glass, and paper. 
7.makerspace at new york hall of science
The Queens space hosts workshops and educational sessions that focus on re-using materials (think manufacturing of the future). While perhaps less technical than other maker spots in the city, the Makerspace at NYSCI introduces youth and beginners to woodworking, plaster-casting, 3D printing and electronics. Their Make Academy will teach you how to cast a mold. The Luminescent Night workshop gets you familiar with light circuitry. 
8.Staten island makerspace
The community co-working space in Staten Island is just a year old but already has world-class facilities. For just $6 a day, you can access a 6,000 sq-ft workshop that includes metalworking and woodworking studios, a computer lab with a 3D printer and scanner as well as a textile studio. The space has a brand-new CNC mill, welding projects, plasma cutting classes as well as monthly membership options with access to conference rooms and lockers. Like Alpha One Lab’s Auriti, Staten Island Co-Founder DB Lampman’s mission is to help New Yorkers evolve from hobbyists to small businesses. The space attracts entrepreneurs from the Island as well as Manhattan and Brooklyn. 

San Francisco

1.Mission science workshop
Its mission is to encourage scientific exploration, particularly for underserved youth. The Workshop originally started out of founder Dan Sudran’s garage, who was a hardware engineer in a past life. He kept lots of of different materials like fossils and electronic equipment in his garage, and children from the neighborhood began to stop by and explore. At that point, Dan decided to start his own space, and now the Mission Science Workshop works with schools in the Mission district of San Francisco and also hosts after-school and summer programs for kids. The Workshop has an almost endless supply of relics and provocative objects: old fossils, live reptiles, and taken-apart LCD screens, to name a few!
2.TechShop
The TechShop in San Francisco runs like a gym membership where members pay a monthly fee to have access to a wide range of machine tools and rapid prototyping equipment. While we were there.
3.Noisebridge
Noisebridge is an award-winning anarchistic educational hackerspace in San Francisco, inspired by hackerspaces in Europe, like the Metalab in Vienna and c-base in Berlin. It is a registered non-profit California corporation, with charitable status.
4.Autodesk’s gallery
the Autodesk Gallery celebrates the creative process and shows how people are using new technology to imagine, design, and create a better world.
5.Rocket space
It is a technology campus in the heart of San Francisco.
6.RallyPad
RallyPad is a launch site for a better tomorrow.It is an incubator and workspace for non-profits and social entrepreneurs in San Francisco and Berlin.
Mission Develop impactful organizations and people for good.
7. Founders Den 
Founders Den isn't actually an incubator at all. Instead, it's a shared office/club for entrepreneurs — all types of entrepreneurs, from experienced ones who have sold companies, to those just starting out. The idea is for them to all come together in this new, large 8,500 square foot space in the SoMa area of San Francisco. We got a chance to tour the place last week — it's very, very nice. But it's a private club. You have to be invited to join.
8.Hacker Dojo
Located in Mountain View It's a warehouse-turned-coworking space that has been converted into several different sections. Once you pass the main lobby area, you'll be entering the main part of the warehouse, where there are tables and chairs everywhere to sit down.
9.Ziploft
located in San Francisco, zipLoft empowers tech startups by giving them access to affordable office space and a vibrant entrepreneurial community. We connect startup and investor ecosystems from around the world.Be inspired and inspire others. Co-work with globally minded tech startups that pursue big ideas. Attend events and grow your network. Get a foothold in your target market.
10.Anchor 
Located in San Francisco, it is one of the most popular co-working space, but not just focuses on hackers, nor offers the space for makers.
11.RockIT CoLabs 
Located in San Francisco, RockIT CoLabs is a small community of bootstrapping entrepreneurs and freelancers who share a friendly coworking space. Facilities include free WiFi, adjustable height desks, whiteboards, presentation equipment, computer monitors, headphones, electronics lab, 3D printer, CNC milling machine, vinyl cutter plotter. Tech service bureau can usually put people in touch with local and international hackers. It offers the space free to instructors who would like to teach free or low cost tech classes.
12.1920c
Located in San Francisco, the China town. It is not your typical workspace. The community is a group of change-makers and go-getters. Those looking for a better place to work and be productive, one that is beyond coworking. A collective space that incorporates wellness, sustainability, local community, and collaboration. A space where you can meet your fellow neighbors and co-create. A space for all types of people to come together to work under one roof.
14.Mothership Hackermoms
Located in Berkeley, CA, Hackermoms holds open houses once a week and all are welcome--moms, dads, kids. It is definitely worth stopping in. Also, because they are a newish organization there is a lot of opportunity to help build things from the ground up and share your voice in helping shape the environment. In addition to providing a space and community where people can become members, they also hold workshops ranging from techy to crafty that are open to the public to register for as well as members.

Los Angeles
Los Angeles Makerspace 
In the fall of 2014, LA Makerspace became the primary provider of STEAM (science, technology, engineering, arts, mathematics) education for the Los Angeles Public Library. LA Makerspace offers free, family-friendly workshops to the public at various LAPL branches. In addition to its public programs, they leverage their expertise to provide “train-the-trainer” professional development for LAPL library staff. LAPL librarians learn to develop and execute STEAM events at their own libraries.Milwaukee, Wisconsin

Milwaukee, Wisconsin
Milwaukee Makerspace
It aims to foster a community of makers by providing an environment in terms of people, equipment and space that supports the creative process and personal growth. Modern software, the Internet and economies of scale have all come together to allow ordinary people with a little bit of know-how to begin blurring the lines between manufacturer and consumer.

Madison, Wisconsin
Sector67 
Sector67 is a non-profit collaborative space in Madison, It dedicated to providing an environment to learn, teach, work-on, build, and create next generation technology; including software, hardware, electronics, art, sewing, metalwork, apps, games, etc.

Anchorage, Kentucky
Anchorage Makerspace 
The Anchorage Makerspace (AMS) is a place for Tinkerers, Creative Artists, Roboticists, 3D Designers, Startups, Evil Genius’s,Infovores, and all who Aspire to Learn More.
At the AMS you will find a competent fabrication shop for your Business Startup. As a Non-Profit Corporation, we are Anchorage’s most flexible design and fabrication shop. Becoming a member gives you 24/7 access to all the tools and resources we have available – an unbeatable deal.If you ever wanted to build a ray-gun or lightsaber, but were missing the tools, workspace (and motivation), you will find your tribe at the AMS! Projects underway are a retro MAME Arcade machine, plasma speakers and a whole slew of home, car and lifestyle automation projects.

Longmont, Colorado
TinkerMill 
TinkerMill is located in Longmont, Colorado and is the largest makerspace in this 10 state region with almost 300 paying members and over 1000 total members active on our online Meetup. It is a non-profit public charity who supports the concepts of a community workshop, and it fields an exceptionally talented membership that supports each other and other community entities in learning, teaching, collaborating and creating.

Philadelphia, Pennsylvania
NextFab
NextFab was founded by Dr. Evan Malone in order to help counteract the extensive offshore outsourcing of US manufacturing and decline of manufacturing education and knowledge-base during the 90's and early 2000's.Dr. Malone aspires to reinvigorate American manufacturing by putting the latest computer-aided design and advanced manufacturing technologies in the hands of innovative individuals and organizations, with the training, support, and friendly expert consultants necessary to help turn ideas into products, and products into businesses.

Seattle
The Makers space
MAKERS is an expansive 11,000 square foot coworking space in downtown Seattle. Perched on a hill overlooking the iconic Elliot’s Bay, MAKERS location is prime in its access to cafes, cocktail bars, shops, and parks. The MAKERS space is modern and chic, welcoming natural light and a clean open feel. Designed with history and sustainability in mind, MAKERS has incorporated many refurbished elements including polished bleacher board floors, salvaged windowpanes and desks made of recycled gym floorboards. MAKERS members enjoy access to premium business amenities, conference rooms, telephone booths, large presentation kitchen, and comfortable lounge area.

Reston, Virginia
Novalabs
Nova Labs is a membership-driven all-volunteer makerspace based in Reston, Virginia that was founded in 2011 with the purpose of empowering everyone to Rediscover the Joy of Making Things.Its current 10,500 sq. ft. facility located at 1916 Isaac Newton Sq West houses classrooms, workspace, incubator offices and a shop that includes both common tools and advanced fabrication equipment.

China
1.People Squared
It is one of the most popular co-working spaces in China for startups, and has 16 locations in Shanghai hand Beijing.
Its mission is to offer the most advantageous and innovational atmoshere for the startups.
2.MakerBar Taipei
Located in Taibei, Makerbar offers various related courses, tools and the workshop for makers.
3.Changee
Founded in 2011 and located in Taibei, it is a co-working space aimed to help people from zero to one.
4.Techspace
Located in Shenzhen, TechSpace is a creative community that provides access to tools and space for makers and start-up teams. You can make your prototypes at TechSpace. We provide professional equipments, tools and service. From mechanical to electronics, metal to 3D printer, skill training to office working service.

Other Countries

Paris, France
Ouishare 
Ouishare is a global community that connects people,organisations and ideas around fairness,openness and trust.
Ouishare connectors organize local events every month to connect collaborative economy enthusiasts. These can be coworking meetup's, informal drinks with pitch sessions from local projects, workshops and larger events such as barcamps, conferences and festivals.

Australia
Solidifier 
This is Australia's first makerspace for hardware startups. Here you can access to a range of prototyping tools, the expert community high-speed internet without any lease requirement.

London, UK
London Hackspace 
This is a non-profit hackerspace in London: a community-run workshop where people come to share tools and knowledge.

Voila! It's Thanksgiving Day !!! A time for joy and good cheer!

Even "Abe"and "Honest" now is thankful for getting away from the "terrible and delicius fate".

Nexpcb is grateful for your support and trust companies.

Blessings from our company to yours! Have a wonderful Thanksgiving!

2. Printing of solder paste
The quality of the PCB is great impacted by the quality of solder paste printing. According to the industry analyst, about 60 percent of the rework board due to the poor printing, this causes our more attention in this process. Three basic steps of printing as following:

1）Fix the stencil in the fixation, place the board under the stencil and align the holes.
2）Scrape the solder paste from the front backwards evenly, the angle of scraper to 45-60 degree is appropriate, then put back the excess paste in the front of stencil.
3）Lift the stencil and remove the board with solder paste carefully, a good print is the final result.

3. Reflower and reflow profile
A correct temperature curve will ensure high-quality soldering joint points. To get a good quality solder point in the PCB assembly, an optimized reflow profile is one of the most important factors.

Table1 Typical PCB reflow temperature setting

Table2 The temperature profile

4. Manual soldering
After preparing the materials of board and components, the tools of flux, solder wire and electric iron, then we get started. But four points should be noted during the soldering:
1)Components for each place should be ready ahead, identify the labels and put them in the neared placement.


2)Wearing a pair of antistatic gloves when soldering, don’t touch the PCB pad and fillets directly.


3)To prevent to soldering scorch, the adjacent components can not be soldered at the same time.


4)Control of soldering temperature, for lower temperature will cause false soldering and high temperature will destroy the components, 200-300 degree will be appropriate.

5. Board test
when all the steps are completed, we have to test the finished board. The test includes appearance test and function test.

To produce a neat and qualified PCB is far more complicated than we described here, it has to go through many more fine processes. The prototyping service of NexPCB factory would be fully meet your custom.

You can also visit our website www.nexpcb.com, to view the specific service information. Here introduce you two boards from NexPCB factory.

 How to generate a PCB stencil file

Communication during production is extremely important. It is necessary in order to create the most accurate and professional stencil files. While designing certain samples, it is necessary for the stencil file to be able to be opened by the following software:

Allegro

Mentor

PADS

Protel2.0

How to export a PCB stencil file

Knowing how to export a PCB stencil file from different design software accurately is vitally important. The available methods for exporting a stencil file from different PCB design software are:

1.PCB design software:

Protel

Orcad

PowerPCB

2.Other professional CAD/CAM software:

CAXA

UG

Hypermill

Let’s take for example converting to Gerber in Protel99SE

Step 1: Click  Protel Stringon the tool column, use the mouse to double click. The software will pop-up below the dialogue box.

Step 2: Press OK and then select the suitable place for this string.

Step 3: Begin converting the Gerber file. Press CAM Manger to start the Output Wizard for exporting Gerber files.

Select the “Gerber (Generates Gerber files)” option and press NEXT to continue.

As indicated above, press NEXT to continue with all default values.

Select the expected exporting layers and press NEXT.

Press NEXT and the window below will appear.

Press NEXT.

Press NEXT.

Press FINISH to complete. Now the file has been successfully converted to Gerber. Do not export Gerber files yet.

Step 4: Press Tool——Scan Wizard, the system will pop-up below the dialogue box.

Select NC Drill to convert to NC Drill.

Press NEXT.

Press FINISH to complete converting. Now the drilling level has been successfully converted.

Step 5: Press Tools – Preferences as pictured below.

It is unnecessary to select a specific destination folder as the PCB drawing library is default, allowing later exportation from that location.

Step 6: Select the required Gerber file export folder and press OK. Select the following options:

Press F9 to export the Gerber file. Gerber has now been successfully converted and stored in the appointed folder. Next, use CAM software for processing.

PCB stencil file check list

Before sending a PCB SMT stencil file to the factory, it is necessary to check it over thoroughly. Especially pay attention to the following areas:

1. Checks to see if there are any errors in the sequence or position of the plate in the  stencil.
2. Checks the PCB drawing size, makes sure the SMT stencil fits the PCB well.
   
3. Checks the material requirements of the PCB SMT stencil.
4. Checks the thickness requirements of the PCB SMT stencil, normally the thickness is 0.13mm or 0.1mm.
5. Checks to see if all the drilling data is correct.

PCB stencil manufacturing technologies

The two main PCB SMT stencil manufacturing technologies used are PCB chemical etching and PCB laser cutting. The quality of the aperture walls is how PCB SMT stencil are valued these days, with rougher edges characterizing an inferior PCB SMT stencil. The progressing of laser technologies has led to this manufacturing process becoming much more mainstream.

PCB chemical etching:

Uses the processed Gerber data to guide a photo-plotter in producing a film, transfers the film to a steel plate and uses an etching machine for processing.

PCB laser cutting:

Imports the processed Gerber data into the laser machine and uses the computer to control the laser machine to drill holes onto the SMT stencil.

You can see how it works out from the following video.

http://www.youtube.com/watch?v=Toaz0Hi3miY

The process of ordering is quite easy and fair to both the PCB manufacturer and the clients. But the process does take some time during the initial stages of a new project. Time is one of the most important factors in marketing. The most important thing is to get your high quality boards ready within the agreed time frame. It is recommendable to verify the design as soon as possible so as to release the product to the market and get the expected feedback faster.

In order to facilitate this, we have created PCB prototype and EMS packages that covers most of the production needs through simple conditions and requirements. The service packages are comprehensive hence our partners do not have to input each of the parameters line by line. Instead, they only need to select the right service package that meets their specification. This in turn helps them create enough time for marketing or other related income generating activities.

We have also realized that our professional partner needs are different from the prototype needs in terms of the technique details or the soldering process required. For example, the professional clients need complex layout boards that have to be soldered using a SMT machine in order to attain the quality of the prototype. On the other hand, prototype partners do not necessarily require complex layouts and can even solder the boards on their own. In response to this, we divided our PCB Packages into prototype and professional categories in order to meet all our customers' needs. We use high technological systems that are very efficient and accurate in delivering the expected results.

In addition to PCB and PCBA, we noticed that the layout procedures takes some time to complete because it requires a lot of experience and skills to do it right. This challenge is not easy and at times the cost is high as well. Based on this fact, we formulated a professional layout design services package for our clients in order to save them time and the money. Using our vast experience, we have the capacity to deliver the layout in less than 7 working days after the tech confirmation. All our personnel are highly trained, professional and committed to ensuring that they meet your specifications and complete your order in time.

The world is round and interconnected, we are committed to helping more and more SME win the future market by cooperating with some of the best partners. You can count on NexPCB to create a quality design as per your needs and preferences at an affordable price.

http://www.ladyada.net/library/pcb/costcalc.html

http://www.tecbridgecircuits.co.uk/priceform.php

http://www.multi-circuit-boards.eu/en/pricing/printed-circuit-boards.html

http://be.eurocircuits.com/shop/ecbasket/services.aspx?lang=en

http://makepcb.com/

http://www.sanmina-sci.com/components/printed-circuit-boards/cost-ratio-calculator/index.php

http://www.leiton.de/en-leiterplatten_kalkulation_start.html

http://www.pcb-pool.com/ppuk/order_productconfiguration_js.html

http://www.pcbya.com/en/calculator.php

http://www.probots.co.in/pcbcostcal.html

http://www.pcboards.eu/en/quote_online_calculate_price_printed_circuit_board_pcb

Despite this fact, which is the most suitable place for production of PCB? Below is a comprehensive analysis of the distribution trends in the world to help you make that important decision.

In 2012, PCB industry experienced slow growth due to certain factors such as economic and political issues. During this period, there was no significant change in sales when compared to 2011 figure. It is estimated that the levels of sales will increase by 5% in 2013. The total turnover recorded in 2012 was approximately 60.3 billion USD. When compared with 2011 turnover which was 58.9 billion USD, only an increase of 2.3% was realized.

Since then, most of the traditional electronic markets such as Japan, USA and Europe have being experiencing low PCB exports due to the slow rate at which the economy and demand is recovering. Apple, which is the leading producing of advanced phone such as iPhone 5 and iPad Mini failed to achieve the expected sales volume. This in turn affected the development of OEM factory as well as the PCB suppliers negatively. Japan and USA recorded a significantly smaller decrease in sales as compared to other global PCB markets.

On the other hand, South Korea was not greatly affected by these changes since most of their development relies on various leading mobile phone production industries such as Samsung. An increase of 12% was recorded during this period. The sales of auto electronics and medical PCB supplies in Europe are always stable. Japanese electronics industry which includes PCB industry was also affected by the political environment in some of the south eastern Asia countries such as Thailand, Malaysia, Vietnam and many more. Part of the production also shifted to some of the South Eastern Asia countries.

PCB companies that are located in Chinese Taiwan area were also affected by the drop in economy and the high client competition for electronic terminals. Most of the companies had to slow down their extension rates in a bid to speed up their merging and integration rates. As a result, some of the companies are now returning to Taiwan and South East Asia.

Research shows that China turnover is at 24.3 billion USD. This is an increase of 3% from 2011 when the total turnover was 23.5 billon USD. It is important to note that China covers 41% of the total global market. Please refer to PCB Industry Distribution in China, too. From the data, it is clear that most of the PCB products are produced in Asian Pacific Area. Environmental and labor costs hinder most middle and low level producers from venturing into this industry fully. Bottom line; it is more economical and convenient to produce PCB products in Asian- Pacific area. You can also decide to hire local agents to help you distribute the products to and from China.

However, you can produce the products locally if your needs meets this criterion:

• If the product requires high precision, strict details requirements and low yield of materials and brands.
• If you urgently need the products. It takes 3 working days for an order to be completed in China.
• If your product requires a lot of customized specification which demands constant communication with the producer.

Otherwise, the best place to outsource for PCB Products is Asian- Pacific or China. This is quite cost effective especially if you make a bulk order. It also more convenient if the products no not demand high technology requirements.

NexPCB is the best choice of this kind.

Taobao is more suitable for the hobbyist.

There is a nice article from dangerousprototypes , it was written by Matseng. Comments below the articles is interesting to read.

Sourcing cheap parts on TaoBao, China’s eBay

Matseng wrote about the Chinese eBay equivalent TaoBao as a great source for cheap electronics components. While the pricing is cheap, the downside is that most sellers only sell locally, so using an agent is a must. Read his full report below.

Local shops are nice when you need a few parts right *now*, but they tend to be rather expensive. If you need a dozen or so of the parts it might be better to purchase from one of the regular major suppliers like Digikey, Mouser or Element14/Farnell, they have usually cheap overnight shipping and somewhat better prices than one of your local smaller shops.

Then there’s eBay where you can find some really good deals, especially if you buy in (small) bulk quantities like 100 leds or 100 micro-usb connectors. Of course you’ll be hit with a 14-20 days delivery time unless you are in the same country as the seller – usually China or USA.

But if you want really low prices on parts in bulk (or even small) quantities you should have a look at TaoBao.com. They are like a Chinese eBay where you can find electronic parts (and almost anything else) for prices that will amaze you. The site is in Chinese only, but if you’re using Chrome it will automagically translate the pages to a very strange, but somewhat understandable, English. “Item” is translated to “Baby” so the search box says “Looking for what baby?” :-)

The shopkeepers normally don’t ship overseas and only accepts local payment, so you need to use an agent to make your purchases. You add the url’s of the items you want to purchase at the agents website. You’ll then pay the agent by credit card, bank transfer or paypal and they will order all your items and collect & repack them to a single box in a warehouse in China. Then they tell you how much to pay for the shipping to you plus their agent fee (varies between 4 and 15% of the total purchase values). Once you have made this second payment they will ship the box from the warehouse to you. Usually they have rather good discounts on the standard EMS/DHL/Fedex rates.

They also usually remove all invoices and other information with prices and then put a low value on the goods in order to reduce the risk of having to pay customs & taxes in your country.

These are some of the parts that I’ve just bought from TaoBao. With prices like this it’s easy to order a few hundred, or in case of the switches a few thousands, of them to have a small stock at home in your lab.

$0.50 100 pcs of 6×6 mm tactile switches
$0.11 SMD 16 Mhz crystal (small 5x3mm, not big HC-49)
$1.60 OLED display 0.96″ 96×64 pixels
$0.03 Piezo beeper/transducer encapsulated & wire-leads
$0.07 IR 38Khz Receiver module
$1.10 LiPo battery 3.7volt 240 mAh
$3.45 Full reel of 5000 pcs 0805 resistors

Try matching these prices at Digikey or even eBay… :-)

One thing that I didn’t buy was this 40w Laser Cutter/Engraver. For $283 it’s a steal even if the quality might be shitty. Unfortunately the shipping costs would most likely be another $283 :-).
Via the forum.

This entry was posted in parts and tagged parts, shopping, TaoBao.

1.5.1  Panel Layout 

Panel can increase productivity and save on production costs; the first thing to consider in panel design is how to place small plates together to make a lager board. It is recommended that the basis of panel design is when the final size is close to the ideal size (Figure1.2.1).

When PCB board’s long side length ≥ 125mm, the boards can be placed as Figure 1.5.1.1 shows. The perfect number of boards is achieved when the final size is consistent with as (Figure1.2.1) requires. The stiffness of this placement is beneficial for the wave-soldering. Figure 1.5.1.1(a) is a typical panel, and Figure 1.5.1.1(b) is suitable for the situation that the rounded corners required after the separation of daughter boards.

(a) V-shaped groove separating method

(b) Slotted hole separating method

Figure 1.5.1.1 Panel

When PCB board’s long side length < 125mm, the boards can be placed as Figure 1.5.1.2 shows. The perfect number of boards is achieved when the final board length is consistent with as Figure1.2.1 requires. When this method is used, the rigidity of boards should be concerned. Figure 1.5.1.2 (a) is a typical V - shaped groove separated panel, there are three perpendicular craft edges to the PCB transfer direction with double-sided deposited copper foil, to enhance the stiffness. Figure 1.5.1.2 (b) is suitable for the situation that the rounded corners required after the separation of daughter boards, and the joint stiffness of separated sides paralleled to the PCB transfer direction should be concerned.

(a)V-shaped groove separating method

(b) The Long Slot plus a Small Circular Hole Separating Method

Figure 1.5.1.2 Panel

Pay attention to the connection between panel and panel, and try to keep each separated connection in a line, as 1.5.1.3 shows.

(a) L Shaped Panel

(b) T Shaped Panel

Figure 1.5.1.3 Panel of Sketch Plate

1.5.2 Connection of Panel

There are two main connection methods for panel: Double face carved V-shaped groove (V-CUT), and the long slot plus a small circular hole (commonly known as stamp hole), depending on the shape of the PCB.

When it is straight-lined connection between plate and plate, the plate margin is neat and does not affect devices installation; the V-CUT method can be used. V-CUT is a through type, and cannot turn in the middle. Currently SMT Board is widely used, characterized with neat and level edges after separation and low processing costs, which is recommended as priority.

a) The two sides of V-CUT line (A side and B side) require a no device and no wire area that is not smaller than 1mm, to avoid the damage to devices and wires when separating.

b) After cutting the V-shaped groove, the remaining thickness X should be 1/4 to 1/3 of the board thickness Y, which is not smaller than 0.4mm. Board bears heavier can take upper limit, and vice versa. The misalignment of the upper and lower sides cut S of V-shaped groove must be less than 0.1mm.

The design requires being consistent with Figure 1.5.2.1.

Figure 1.5.2.1 Design Requirements of V-Cut

The connection method of long slot plus a small circular hole, also known as stamp hole method, is suitable for any shapes of daughter boards. As the margin area is not neat and level after separation, it is not recommended for those PCB with fixed conduit ferrule.

Requirements for the long slot plus a small circular hole method: The width of long slot is usually between 1.6mm and 3.0mm, and the length is about 25mm to 80mm, the connection bridge between slot and slot is generally 5mm to 7mm, with several small circular holes placed, and the diameter Ф of these holes is 0.8mm ～1 mm, the distance from the center of the aperture to the outside is 0.4mm – 0.5mm: Thicker boards take smaller value and thinner boards take larger value, it is a typical value in Figure 1.5.2.2. The length of the cutting groove is based on the PCB routing directions, assembly process, and the size of PCB. The smaller the aperture, the neater the margin area.

Figure 1.5.2.2 The Long Slot plus a Small Circular Hole Method

When design connection bridge, it is mainly to consider: whether the margin area after separation is neat or not; whether it is convenient to separate or not; is the stiffness enough for production; the material, thickness and total weight of single plate; the distance between connection bridges (the recommended distance is 60mm). In order to make the margin area neat after separation, the separating holes are usually placed on the sidelines or slightly within the daughter board.

The Harmonized Tariff Schedule of the United States

Anatomy of the USA HTS Code of 8473309100.

The primary purpose for battery certification is to meet the demands of air shipment, and to comply with the international air parcel safety requirements.

1. UN 38.3 Testing Report

UN 38.3 refers to the lithium ion battery testing in section 38.3 of <Manual of Tests and Criteria>, compiled by United Nations Committee of Experts on the Transport of Dangerous Goods, which requires that all transportation of lithium ion batteries products or equipment containing lithium ion batteries must first complete the altitude simulation test, high low temperature cycling test, and vibratory test, blow test, 55℃ external short circuit, and impact test, overcharge test, and forced-discharge test, in order to guarantee the air transport security.

1) UN 38.3 Report certifying process

a. Firstly registration on Shanghai Research Institute of Chemical Industry Testing Center (SRICI) website, www.ghs.cn.

b. Send the consignation order number, 25 batteries, and 25 cells samples to the Research Institute of Chemical Industry.

c. Report will be issued in 30 working days after samples received.

2) UN 38.3 Test Report sample

2. Identification and Classification Report for Air Transport of Goods

After the battery UN 38.3 report issued, an air identification report for dangerous goods transport needs to be made, which identifies the battery transport environment, (such as what forms of batteries are placed in products, or how products are packaged, and etc.)

1) Requirements for air testing report process and samples

a. Send a whole set of product and battery samples to the Research Institute of Chemical Industry, attaching product package picture, which includes single packaging and carton packaging design drawings.

b. Report will be issued in 3 working days after samples received.

c. Afterwards all shipments and packages must follow the identified form to be delivered (The number, packages and layout of each carton, and the assembled style of products must be the same); if there is any change of them, a new air identification report must be made.

Lithium Ion Battery Packaging Requirements

Lithium ion battery should be placed in solid package, unless installed in device, packaging should be able to prevent short circuits, and in one package it must be prevented to contact with the conductive material that can lead to short circuits.

1. Lithium Ion Battery Box Packaging Requirements

1) Lithium ion battery operation label
Lithium ion battery operation label must be pasted (there is no need to paste the operation label on packages if batteries are installed in devices, and there are less than 4 battery cells or 2 batteries in each device.)

2) Together along transport document (e.g. MSDS)
If there is an operation label on box, it must come together with a document, this document can explain: there are lithium ion cells or batteries in package; it must be carefully operated; risk of flammability if broken; if the package is damaged, specific procedure must be followed, and to check and repack if necessary; and contact number for more information.

a. Material Safety Data Sheet(MSDS) once was a nine-section chemical safety document detailing the toxicity, use, storage, handling and emergency procedures of hazardous substances. Under the new GHS, Globally Harmonized System, the name has been changed from MSDS and simplified to SDS, Safety Data Sheet.

3) 1.2m Drop Test for package contains lithium cells or batteries
1.2m drop test for different surfaces and sides (individual transport or batteries and battery cells transported with devices need to be tested. Testing location: surface, edges and angles). Criteria for passing the 1.2 m drop test: Each package must be capable of withstanding the test without:

a. Damage or leakage to cells or batteries contained therein.

b. Shifting of the contents so as to allow battery to battery (or cell to cell) contact or short-circuit.

c. Release of contents.

4) Other
a. Battery package transported with devices: the maximum number of batteries inside each package is the minimum number that support enough power for equipment and two backup batteries.

b. If batteries are installed in equipment during transport, there must be effective measures to prevent accidental activation of equipment.

After login the WO system. Click List Product at the left-side-menu.

Select the specific Product, which your want to add a new version on.

In the Product Version Block, you could input necessary information, then click "Add the version flag"

2. Add File

After a new version flag was created, in the same page, you could add files in the “Product Attachments” block now as following:

           Choose File Type;
           Choose New Version;
           File Name;
           Add files from your local computer, please achieved them as zip if possible;

Please wait until coming “upload success!...” message, then Click "Add File".

After finishing adding file, you could see the recent uploaded files are listed in “Product Attachments”.

Continual to add more files if necessary.

Please download PDF format of this page

Step 1: Log in

After you sign in, the home page is the Overview of all the work orders. Left side of the page. Left side of the web is the main parts of the WO system: Work Orders(WO), Product, Shipment, Admin.

Step 2: Add Product Group

It's important to create the product library for your products before Create New Work Order. Just Click Product Group in Product Part.

Then add the Groups name via click Add Product Group link, and add the Group Name.

You can click the Product Group to list all the Group Names you have added.

Step 3: Add Product

a) Add Product Name

Just click Add Product link and add the Description of your product quick and simple.

Click Add Product button

b) Add Version Flag

Set the version flag and upload product's files for each version.

c) Add File

Add several files, related to the specific product version to manufacture.

Step 4: Create Work Order

Click the overview link under Work Orders part, and click Create New Work Order button.

Click Save button when you have done.

Congratulation! The work order is created, and the team of NexPCB will create your design. You can just focus on the market and the design now!

 Please download PDF format of this page

1.1 The placement of thermosensors

d) No touching or stacking of components to meet the space requirements of device installation.

1.2 Bad Placement examples

e) High-heat-load components, such as power inductors or power regulators, cannot be placed to get too close to the technology edge (or panel edge), and the distance to the edge must be above 20mm, which is in order to avoid temperature goes uneven of reflow oven guide rail that may affect soldering.

1.3 The distance between high-heat-load components and technology edge (or panel edge)

f) High-heat-load components, such as power inductors or power regulators, cannot be placed closely to each other. This includes the positive and negative sides, and the distance between each other must be 20mm or above, which is to avoid large PCB partial heat load.

1.4 The distance between high-heat-load components

2 Requirements for THD Devices Placement

a) Except for structural components with special requirements, all the THD devices must be placed on the positive side.

b) The distance between adjacent components is shown in figure 2.1.

2.1 The distance between adjacent components

c) To meet the operating space of manual soldering, maintenance and inspection requirements, as shown in Figure 2.2.

2.2 Searing-iron operating space

d) When components are placed on one side of plug-in devices, the minimum bonding pad edge space can be processed for parallel soldering joints placement is 3.0mm; if it is the vertical soldering joints placement, the minimum bonding pad edge space that can be processed is 1.0mm; see figure 2.3.

2.3 One side SMD components placement

3 SMD Components Placement Requirements

a) Fine-pitch devices (including BGA, 0.4mm and 0.5mm QFP) are recommended to be placed on the same side.

b) Polar patches are arranged in the same direction as much as possible, and the visual angle required will be less than 60o; as the soldering joints inspection will be affected if higher devices are placed close to lower devices; as shown in 3.1.

3.1 Soldering joint points visual inspection

c) There must be forbidden zone around the BGA devices（ BGA）.

3.2 Requirements of the forbidden zone between BGA and other devices

d) 2mm forbidden zone must be left out around QFN.

e) 2mm forbidden zone must be left out around module.

f) It is not recommended that two SMD wing shaped pin to overlap as a compatible design. Take SOP packages as an example, shown in figure 3.3.

3.3 Two SOP packages components compatible design

g) It is allowed to design THD and SMD stacked together when there is no influence on the THD soldering by the SMD bonding pad and the solder paste printed on it. The following figure 3.4 shows the example of DIP-8 and SOIC-8 packages components compatible design.

3.4 DIP-8 and SOIC-8 packages components compatible design

h) Requirements for the distance between SMD: same kind of device: ≥0.5mm; different kinds of device: the distance should meet the requirements of soldering joints inspection, which requires the visual angle ≤60o.

      Note 1: The measurement volume of distance value is chosen the larger one from the ponding pad and device itself.


      Note 2: When the lower SMD ponding pad is placed closely to the higher device, the distance between them should meet the requirement of soldering joints inspection, which means the visual angle should be less than 60 o. See figure 3.5.

3.5 Distance requirement of devices placement

i) The distance between fine-pitch devices and the panel routing edge should be more than 10mm; otherwise it will affect the solder paster print quality.

j) The distance between other non-fine-pitch devices and the panel routing edge should be more than 5mm, and the distance between other non-fine-pitch devices and the non-transmission side panel edge should be more than 3mm. see figure 3.6.

3.6 Requirement of forbidden zone between SMD and panel edge

The distance from inner and outer routing to the panel edge, the distance from the copper to the panel edge, and the dimension of non-plated through hole must be satisfy the requirements in the table below.

1.1 Guide Rail Depth

There must be no routing in the area where devices with metal shell (such as radiators, power modules, horizontal voltage regulators, and ferrite inductor, and etc.) directly contact with the PCB, in addition, extending outward 1.5mm of this area is the forbidden zone for surface routing. Shown in Figure 1.2.

1.2 Forbidden Zone for Surface Routing of Devices with Metal Shel

2. Routing Ways

When circuit is connected with devices, in principle they can connect at any point. However, for reflow soldering devices, the design should follow the principles below:

Devices like resistance and capacitor jointing on two bonding pads should be connected with the printed routings that go outlet equally to the line width from the central position of the bonding pad. Outgoing lines whose width is smaller or equal to 12 mil don’t have to follow the rule. Line width must not exceed the minimum side length of bonding pad.

2.1 Requirements for Line Width

a) Devices must go outlet from the central head face of the bonding pad.

2.2 Outlet from the Central Bonding Pad

b) When the routing connecting with bonding pad is wider than bonding pad, it cannot cover the bonding pad that it should route from the end of bonding pad; when fine-pitch SMT bonding pad pin needs to be connected, it should be joint from the outer of the pin rather than the middle.

2.3 Requirement 1 for Bonding Pad Routing



2.4 Requirement 2 for Bonding Pad Routing

c) The routing going through BGA holes and connecting with the bonding pad needs to use the way of dog bones. See in 2.5.

2.5 Joint through BGA Holes to Bonding Pad

3. Copper Polygon

If there is a large area without linear and graphics of the outside, it is recommended to be covered by copper grids in this zone to make the whole panel surface of copper spread evenly. The size of square in the copper grids is about 25mil x25mil.

Note: The inside layer doesn’t need copper grids design.



3.1 Large Area Copper Grid Design

When large area of devices from the power zone and ground terminal zone connect with bonding pads, they should be designed into the shape shown in the following graph, so as to avoid large area of copper heat too fast to affect soldering quality or cause a cold solder joint.

3.2 Large Area Copper and Joint of Devices and Bonding Pads Design

1.1 The design of through hole needs to meet the requirement that the hole diameter to the panel thickness ratio should be greater than 1/6.

1.2 Distance between holes.

Figure 1.2 Distance between holes

PS: a). The distance between hole plates is: A≥20mil;
b). The distance between hole plate and copper foil is: B≥20mil, C≥20mil;
c). The minimum distance between PTH and hole to outline is the distance that can ensure the distance from the bonding pad to the hole to outline is: D≥20mil;
d). The recommended minimum distance between NPTH and hole to outline is E≥40mil.

1.3 The location of through hole is related with the reflowing soldering process. The through holes cannot be designed on bonding pad, and they should be connected by a short printed line, the distance from hole wall to bonding pad must be greater than 0.2 mm, otherwise it is easier to produce flaws such as tombstone setting, useless soldering, and less tin, which is shown as follow:

Figure 1.3 The Location Design of Through Hole

1.4 There should be no through holes in the extending outward 1.5 mm area of the contacting part of devices metal shell and PCB.

1.5 Through holes cannot be designed in the central area between two bonding pads that are on the chip component of the soldering face, see figure 1.5.

Figure 1.5 Incorrect Design of Through Hole Position

2. Locating Hole Design

2.1 Hole types selection

Figure 2.1 Types of Holes

2.2 Design of forbidden zone

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NexPCB is the recommended Indiegogo EMS provider. It provides electronic manufacturing services for PCB’s, which include PCB layout design, fabrication, assembly, and supply chain management. For more information, please download this Indiegogo's Hardware Handbook at http://landing.indiegogo.com/hardwarehandbook after subscription.

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We sincerely to announce that we are very supportive of crowdfunding Website as Indiegogo, and to establish a horizontal cooperation, to provide better service and support for more makers.

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Figure 2.1.1 Schematic Diagram of Rectangle Component Shape and Bonding Pad Graphic



Commonly used bonding pads ’ size for resistor and capacitor are listed in Table 2.1.1(a) and Table 2.1.1(b).

Table 2.1.1(a) Bonding Pad Size of Chip Resistor





Table 2.1.1(b) Bonding Pad Size of Chip Capacitor

2.1.2 Molded plastic encapsulated tantalum capacitor pad design

Shapes of tantalum capacitor and bonding pad are seen in Figure 2.1.2. Bonding pads ’ width is calculated according to equation (5), length is according to (6), and gap is according to (7).






In the equations
A -- the width of bonding pad, mm(mil)
B -- the length of bonding pad, mm(mil)
G -- gap length between pads, mm(mil)
W max -- the maximum width of component, mm(mil)
H max -- the maximum height of component (referring to the soldering side), mm(mil)
T min -- the minimum width of component side bonding tip, mm(mil)
L max -- the maximum length of component, mm(mil)
T max -- the maximum width of component side bonding tip, mm(mil)
K=0.25mm(10mil)

Figure 2.1.2 Shapes of Tantalum Capacitor and Bonding Pad

Commonly used molded plastic tantalum capacitor bonding pad sizes are listed in Table 2.1.2.

Table 2.1.2 Molded Plastic Tantalum Capacitor Bonding Pad Sizes

 2.1.3 Cylindrical component bonding pad design

The shape of bonding pad is rectangle. When the reflow soldering process is applied, a concave groove must be designed (See Figure 2.1.3), and the width is usually 0.30.05mm. But if components are fixed by cementing compound before soldering, then there is no need to design a concave groove.

Commonly used cylindrical component bonding pad width, length, and gap, and length of concave groove are listed in Table 2.1.3.

Table 2.1.3 Cylindrical SMD Bonding Pad Size

Figure 2.1.3 Cylindrical SMD Bonding Pad

2.2 Bonding pad design with devices

2.2.1 General rules

a) Width of bonding pad and pad distance


Table 2.2.1 Different Pin Center Distance with their Corresponding Bonding Pad Width and Pad Distance

b) Bonding pad length is 2.5 to 3 times of the solder PIN length, 3 times is recommended.

2.2.2. Transistor bonding pad graphic design

The center distance of bonding pad equals the center distance of leading wires. The size of bonding pad extend 0.38mm from around the soldering end (15mil). For most commonly used bonding pad SOT23、SOT89、SOT143, see Figure 2.2.2 (a), 2.2.2(b), 2.2.2(c).

Figure 2.2.2(a) Sketch of SOT23 Bonding Pad (mm)


Figure 2.2.2(b) Sketch of SOT89 Bonding Pad (mm)

Figure 2.2.2(c) Sketch of SOT143 Bonding Pad (mm)

2.2.3 SOP Device bonding design

SOP shape and bonding pad shown by Figure 2.2.3, calculation of bonding pad width, distance between pads, bonding pad length by 2.2.1. Calculation of the inner flank distance of two rows bonding pad by equation (8).







In the equation
D -- the relative distance of two sides bonding pad, mm (mil)
F -- the width of device, mm(mil)
K＝0.254mm(10mil)

Figure 2.2.3 SOP Shape and Bonding Pad

2.2.4 PLCC devices bonding pad design

The shape of PLCC and bonding pad see Figure 2.2.4. Usually, the width of bonding pad is 0.76 mm, distance between pads is 0.51 mm, the length of pad is 2 mm, the equation (9) and (10) are for calculation of outer flank distance of boding pad.







In the equation
A -- landscape orientation outer flank distance of boding pad, mm (mil)
B -- lengthwise outer flank distance of boding pad, mm (mil)
C1/C2 -- width of the device (include the pin), mm (mil)
K＝0.76mm(30mil)

Figure 2.2.4 PLCC Shape and Bonding Pad

2.2.5 BGA and Ball grid array components bonding pad design rules

a). The center of every solder ball has to dovetail with the corresponding solder ball center at BGA bottom.
b). The pattern of PCB bonding pad is solid circle, through holes must not be made on the pad.
c). The width of conducting wires need to be same,in general 0.15mm~0.2mm.
d). Soldmask size has to be 0.1mm~0.15mm bigger than the bonding pad.
e). After though holes being punched and plated, block them with dielectric material and conductive adhesive, with its height should no taller than the bonding pad.
f). To process the screen graphics surrounding the four corners of BGA devices, line weight should be 0.2mm~0.25mm.
g). The bonding pad of BGA devices is round shape. Generally speaking, the diameter of bonding pad is 20% smaller than the solder ball’s. As for the pylomes beside the pad, soldmask need to be performed so as not to cause short circuit and cold solder joint by the loss of solder.



2.2.6 QFN (MLF、LLP and etc) type component bonding pad design

Figure 2.2.6 (a) and 2.2.6 (b)

Definition of QFN bonding pad:
A: Center distance of bonding pad
B: Width of bonding pad
C: Length of bonding pad
D: Minimum distance between function pad and thermal pad
E: Minimum distance between function pad and function pad
F、G：Maximum distance between function pads
H、I：Size of thermal pad
H1：Heat pad cooling vents distance
Φ：Diameter of vents (hole number decided by the size of grounding pads)



QFN bonding pad design parameter (see Table 2.2.6)

Table 2.2.6 QFN Bonding Pad Design Parameter

Table 1.1 Ring Width of Cartridge Components Bonding Pads Design

For the PCB with 1.6mm to 2mm panel thickness, the diameter of mounting hole and size of bonding pads of commonly used components are seen in Table 1.2 and 1.3.

Table 1.2 Bonding Pads and Hole Diameter of Commonly Used Cartridge Components

Table 1.3 Backboard Commonly Uses 2mm Connector Crimping Hole and Bonding Pads

Commonly used elliptical bonding pads are shown in Table 1.4

Table 1.4 Commonly Used Elliptical Bonding Pads 

High speed differential pair signals such as PCIe, SATA, USB, HDMI etc. need to be routed with differential impedance. This is the impedance between the two signal traces of a pair. As the signals are also referenced to ground, each differential pair signal also has a single ended impedance. When selecting trace geometry, priority should be given to matching the differential impedance over the single ended impedance. The differential impedance is always smaller than twice the single ended impedance

The signals allow a certain impedance tolerance (e.g. 50Ω ±15%). When defining trace geometry, try to keep the calculated impedance value as close as possible to the exact impedance value. This allows greater flexibility during PCB manufacture. Variation in impedances will occur between different production lots. If the calculated impedance is in the middle of the tolerance band, this will help ensure maximum production yield.

Different tools can be used for calculating the trace impedance. Polar Instruments offers a widely used tool. Many PCB manufacturers use this tool. PCB manufacturers can often help customers with impedance calculations, and it is suggested you work with your chosen PCB manufacturer during your design. Many PCB layout tools offer a very basic impedance calculator. Unfortunately, these calculators are not reliable in all situations.

Traces on the top or bottom layer have only one reference plane. These traces are called microstrip. The following figure shows the geometry of such microstrips. H1 is the distance from the trace to the according reference plane. Er1 is the relative permittivity of the isolation material. The traces have a trapezoid form due to the etching process. In the layout tool, the traces have to be designed with a width of W1. W2 depends on the trace height (T1) and the duration of the etching. Contact your PCB manufacturer in order to get the information about the resulting width W2. S1 is the spacing within a differential pair.

  

Traces in the inner layer of a PCB have two reference planes, reducing electromagnetic emissions and increasing immunity to external noise sources. These traces are called stripline. The following figure shows the geometry of such striplines. When making impedance calculation of striplines, special care needs to be taken when it comes to the isolation thickness H1 and H2. H1 is the thickness of the core material. The traces are embedded in the prepreg material. As the traces have a finite height, the prepreg height H2 depends on the copper density. The relative permittivity of the core and prepreg material can be slightly different. Many impedance calculation tools can take this in account. 

The following table shows typical trace geometries for traces using in the six layer stack-up,

The following table shows typical trace geometries for traces used in the eight layer stack-up,

1. Principles of electronic reliability design

Principles of electronic reliability design include: RAMS definition and evaluation indicators, reliability model of electronic equipment, and factors affecting the rate of failure of the system, electronic product reliability indicators, determination of working environment conditions, system design and micro-design, process review and test, and design specifications and technical standards.

Generally speaking, the designing principles are difficult to establish connections with actual design directly. This paragraph mainly concerns about theories on technology. You all know Qian xuesen, right? What were his advantages, electronic, mechanical, or software, testing, or management? No! They were systemmatic method theory and engineering calculations. When we need to determine the selection of a circuit component, if there is a basic formula to directly tell us should pay attention to which indications, will component selection and circuit design still be difficult?

For example, a socket cable that is required to pass current in 10A, so is it better to use two 8A parallel wires to shunt, or to use a cable that is capable to pass the current in 14A? It can easily get the answer via reliability model. Driving a luminotron, is it better to use dynatron, or to use operational amplifier?
I went to Qingdao some time ago and visited the Museum of Tsingtao beer. I found that Germany's motor and Japan's fans produced a century ago, and they are still working. This is amazing. Factors affecting the rate of failure of the system can tell you the answer to this situation. Nowadays, neither Germany, Japan nor us can make motors and fans that could run a century.

If you want to improve the electronic reliability, what specific issues should you start with? These are problems can be solved by theoretical methods and engineering calculations. Mr. Qian passed away, but his wisdom and thought must be passed on. What I can do is to spread Mr. Qian’s ideas, wishing more people get involved and to be more widely understood and applied.

2. Circuit reliability design specifications

The circuit reliability design specifications include derating design (derating parameters and derating factors), thermal design (thermal design calculation, thermal design test and heat component selection), and circuit security design specification, EMC design, PCB design (layout and routing, grounding, impedance matching, and processing), usability design (usability factors, user operation analysis, and design guidelines), and maintainability design (maintainability rating, evaluation and design methods).

The core idea of circuit reliability design specifications is the monitoring processes rather than the monitoring results, for the most common example, design specification is the maintenance of pregnancy, to guarantee the prepotency. These are the conclusions made by previous experience, if you follow these design methods, then the reliability risks will be excluded.

Let’s take the thermal design as an example, you don’t need to worry about the elimination of heat is not enough if the heat output method is determined via the calculation of thermal power density and heat flow density; so long as there is sufficient remaining amount, you don’t need to worry about ‘A blind man riding a blind horse, midnight comes to the deep pool’ if you choose the fan and heat sink in accordance with the calculation of the thermal resistance and junction temperature.

PCB grounding seems to be the easiest as well as the most complicated problem, whether is there any grounding thought that is widely approved and only makes us happy without any worrying? The answer is “Yes”.

Usability seems to have little influence on us, just like we are going to have an interview, the key factors to success seem to be the academic certificates, work experience, and etc., will a piece of leek leaf on the front teeth lead to failure? The color, size, and the feel and strength required when pressing, the shape, and the layout of buttons, and displayed contents, methods, angle, and size, what’s the difference between a piece of leek leaf on the front teeth and all of the above? For users, the most common saying is “interface is system”. Users don’t know the advanced theory and internal structure, they only care about that the internal stuff is as long as well used, and the rest they care about is just the appearance. Especially for new users, appearance is the primary factor for determining to purchase or not. You know, in university, beautiful girls always have more pursuers.

Maintainability directly determines the cost. Maintainability can be divided into three levels: site level, office level, and headquarter level. Value of maintenance tools, quantity of supporting tools, and level of maintenance personnel, number of maintenance personnel, and sufficient degree of accessories are all different from each levels. Let’s think, a maintenance level that is defined as site level, has a cover that can only be moved by three people, then how many maintenance staffs are required to go on this business trip? In addition, a maintenance level that is defined as office level, requires spectrum analyzers, logic analyzers, oscilloscopes and other high-end instruments to repair, then what will the cost be? Let alone the other facilities and equipment.

3. Reliability testing

Reliability testing includes standards compliance test, edge extreme conditions test, and fault-tolerance test, HALT test, destructive test, concealed condition test, and interface condition test. After communicating with many technicians, they all want to do a good job in reliability design, but generally reflect two problems: the first one is the lack of experience, and the other is that they can’t find any problems at home, but at site there will be problems. Lacking of experience problems can be solved by the methods from the second part, and the methods to solve testing problems can be found in this section. The core point of testing is the design of test case, which concentrates in two parts: one is trying to impersonate the worst conditions of users’ sites as much as possible; and the other is to target at the possible failure mechanism, to increase destructive factors intentionally to stimulate problems, so that to find the weak points and do improvement. But it should be noted that to some extent many tests are disruptive, which needs to be analyzed, and machines having a destructive test can never leave the factory.

4. Components selection

Components selection includes basic principles, classification of components series, characteristics, indicators, and reliability application safety notice, and etc. Components include: capacitors, resistors, diode triode, connectors, crystal oscillator, electronically controlled optical device (coupling, LED), AD/DA and op-amp, electro-mechanical devices and energy conversion devices (switching power supplies, power conversion IC, transformers), digital IC, protective devices (fuses, magnetic ring and magnetic beads, and voltage dependent resistor, TVS tubes), and power modules, and so on.

A slogan is popular in girls:＂marrying a prosperous man is more practical than working hard”, although the positive and negative sides are debating fiercely online, there is one truth that no one can deny, in the end the ration of girls who married well is much higher than girls who do good. Doing a good job equals designing a good circuit, and marrying well means well selection of components. For capacitors as an example, the difference between tantalum electrolysis and aluminum electrolysis, the difference between electrolysis and ceramic chip, and the difference between wire-wound resistor and film resistor, which indicators needs more attention of digital IC, what indexes are for selecting protective devices, as we all know that, if bodyguard and security deterioration can be a big trouble. 　

The manufacturing process and characteristics leaded from the process are we need to understand and try to avoid in applications, such as inductance value of wire-wound resistor is large, as well as magnitude of leakage current of paper capacitor, and ceramic capacitor resistance to temperature change rate and resistance to vibration level are low, TVS resistance to surge current is small but its responding time is short, and the effect of magnetic ring depends on material and equipment, and vibration resistance, and so on.

5. Components failure mechanism and analysis methods

Components failure mechanism and analysis methods include common failure mechanism, analysis methods and tools. All the contents above are about how to prevent circuit not to work properly and devices to break, but no one is wise at all times, once it is broken, we should feel like getting a valuable treasure rather than give a wide berth. Drivers all know that where is the best place to practice driving skills, on the high way? No, it’s the city where the traffic is not that good. The development of society is a process to find problems and solve problems. Problems are not terrible, but it is awful to let the same type of problems occur over and over again.

Components failure mechanism analysis is based on a basic improvement method, “based on failure mechanism precaution”. Once a problem is detected, to avoid factors that can cause problems, and then forming a specification, which every one is going to follow when do deign, there will be no more problems.

For example, the protection of ESD, many companies are doing it, methods include humidifying, which may cause the problem of MSD: after wave soldering and reflow soldering you can find some pins of some components are open to VCC and GND via the I/V curve test, at this period MSD problem should be considered. The solving method is to heat several hours before soldering to let the moisture out. Or one device is burnt out, we need to check and test which pin is broken, and the phenomenon. By using multimeter, I/V curve diagram instrument, oscilloscope, and X ray to find out failure mechanism, and then tracking down the problem by following clues, to get to the circuit linked to the pin, to analyze the circuit and manufacturing process inside factory, so we can find out the point leading to the failure mechanism and make improvement.

6. Circuit reliability design micro-management method

It’s very easy to improve reliability design micro-management method, including three parts: software, AAR, and checklist. Logically, technical content should not be mixed with management, but management can contribute to technology. For example, in company there is someone mastering one knowledge point, but no one knows it, then management measures can stimulate him to say it out and help others with practice, which is equivalent to a non-technical solution solve a technical problem.

This part aims at eradicating the impediment when carrying out the reliability works. Impediment one is people may easily become lazy. People may find that the cost of having the guidance documents could be huge, therefore they plunged into the designing work with their blind faith. One of the roles for using designing softwares is to lower the technical communication barriers. Impediment two is lack of professional experience and expertise. We should have After Action Review activities, and summarize the cause, phenomena, methods and etc, and we could share these information though the software. As we are always working hard and improving ourselves, there is no need to be afraid of lack of experience. Fast growing can also be considered as the means of solving technical problems. Impediment three is a certain person could always be narrow-minded, therefore, it is reasonable to have the designing work cross-checked and let the missed information exposed. Checklist is relatively systematic, for it serves as a good tool for designers to self-check as well as reference for other experts to find out the missing information. It could be a good learning material for beginners and useful advanced designers for reference.

—NexPCB translate from the Internet blog