9 Tips to Increase the Quality of your PCBA Prototype

The quality of your quick turn prototypes can suffer because by their very nature prototypes are designed and built fast to prove a concept.  This can mean less time spent designing for assembly or manufacturing, less time spent designing for test, and less time spent reviewing.  All of these can hurt the quality of your prototype assembly.  But quality doesn’t have to be completely sacrificed on the altar of quick turn prototyping.  Below are nine tips to increase the quality of your PCBA prototype.

 

1. Simplify your prototype

Focus your early quick turn prototype on the part, or parts, of your design that needs to be prototyped.  Prototype smaller parts of your design on pluggable cards.  Prototype your design to work in conjunction with a vendor demo or eval board.

 

2. Enlarge your prototype

Often, you can shrink your design for production later. When you design your prototype, make it bigger.  Use a larger form factor for your PCB, use larger components that are easier to assemble and rework, and leave room for debugging and probing for test.

 

3. Design options into your prototype

Haven’t decided between two components?  Put them both on your prototype, with a jumper to enable one or the other!   Design your board with pull-ups and pull-downs on all open drain nets and setting selections pins.  Install all programming headers on your prototype.

 

4. Avoid components of unknown provenance

Bad components can sink your prototype.  Use components from reputable distributors, and have your prototype built at reputable PCB assembly houses.  Counterfeit components can have poor quality control, poor tolerance control, or even use banned substances.

 

5. Use materials and processes common to your assembly house

Even PCB assembly houses that offer myriad options have certain standard materials and processes that, if used in your prototype, will remove variables that add risk to your prototype build.  Talk to your assembler to determine the selections you can make that they are most comfortable with.

 

6. Use a quick turn prototype assembly house

Quick turn prototypers have their entire process tuned to meet your high-mix, low-volume needs.  Contract manufacturers focused on high volume production do not.  CMs are more likely to ask you to change your design for ease of high volume manufacturing than to care about your prototype quality.

 

7. Provide intelligent CAD files to your assembly house

Intelligent CAD files, such as ODB++ files, provide your assembler all the information they need to quickly and correctly build your prototype.  By contrast, Gerber files provide no intelligence and add time and risk to your prototype assembly.

 

8. Request a Design for Assembly automated check

Design for assembly checks are automated checks on your design files that identify potential manufacturing issues – before they happen.  These checks will check things like component footprints against manufacturability standards. A good DfA analysis could increase your prototype quality by an order of magnitude.

 

9. Complete post-build inspections

Post build inspections such as automated optical inspection (AOI) and 5DX automated x-ray inspection can catch assembly errors both visible and invisible to the naked eye.  And a good assembly house will fix any assembly errors they find (if they can), increasing your prototype quality.