While I enjoy solitude in remote areas of nature, no man is an island. Sharing a backpacking trip with friends livens the mood and makes a memorable trip into shared camaraderie. At the very least, traveling with a partner bolsters safety and also helps reduce a single person’s backpack load and safety responsibilities. Of course, not just anyone can go (or is even willing), and an unprepared body or pack will likely cause more slowdown than going it alone. Partnerships are thus built on shared responsibility, but there are clear benefits when everyone pulls their weight.
Whether in the backcountry or building PCBs, the choice of partner matters. While searching for a PCB contract manufacturer to partner with for building your circuit boards, establishing a high level of communication and trust is tantamount to a successful final product. Whether a novice or experienced in design, some subtle layout choices can develop into major manufacturing problems further down the road if left unaddressed.
PCB Assembly Best Practices
Sidestepping production issues before potential problems arise saves time, money, and frustration. PCB assemblers with a strong focus on quality will deliver a superior board in minimum time while improving the design for current and future iterations.
How to Differentiate Assembly Quality Practices
|Substandard Assembly||Good Assembly||Best Assembly|
|Design Review||Lack of all-encompassing review leads to excessive respins and time lost to redesign.||Review can assess where design needs to adapt to aid manufacturing in a minimal number of respins.||In addition to accomplishing redesign in a minimal number of respins, identifies ways to improve manufacturability at the design stage.|
|BOM Review||Takes BOM as-is and does not attempt to navigate the market shortages more than necessary.||Uses purchasing power and cultivates business relationships for sourcing and procurement.||Stays on top of market trends to gauge the obsolescence of parts and keeps an ample supply of components.|
|Documentation||Poor, lacking, or inaccurate documentation can cause errors in production and design.||Large, legible, and unambiguous manufacturing files and design documents foster clear communication.||Documentation and file encoding will preserve design intent and capture the necessary details for future revisions, regardless of who designs or manufactures.|
|Testing||Coverage is not comprehensive or results are not optimally folded back into the manufacturing process.||Practices aim to maximize board quality using iterative production methods to capitalize on test analyses.||Testing is proactive and aimed not only at limiting defect escape but detecting it at the earliest occurrence to cut down on turnaround time.|
Common Problems with PCB Contract Manufacturers
Given the high degree of technical expertise and equipment utilized in PCB production, it is a deeply involved service between client and manufacturer. There must be a rock-solid foundation between designers and CM, especially when a design is gradually building from proof of concept to NPI (and many prototypes).
Certainly, size alone can’t be the only determining factor when deciding upon a CM. Still, a larger workforce and facility also tend to contain better equipment, more proficiency, and higher-value experience. However, the largest PCB assembly factories may only be economically viable with large production quantities. That scenario amounts to putting the cart before the horse regarding an NPI.
Location is another important consideration. For example, is it possible to physically tour the facility before placing an order to assuage whether the shop is organized, professional, and knowledgeable enough to handle any challenges they may encounter during board design? While virtual tours have certainly bridged the gap during the height of the COVID-19 pandemic years, most prefer the accessibility and personability of a face-to-face meeting.
Unfortunately, not every CM builds equally. Look to spot any of these issues early that could suggest an ill-suited partnership for manufacturing:
- Inconsistent manufacturing practices. Is there a high variance in the performance or yield of the board? Boards must retain tight tolerances to match their intended use and function. Manufacturing quality should not stray, and changes made to production should be carefully considered.
- Undocumented changes. Speaking of changes, these should be well-communicated by the manufacturer without delay, alongside a justification for why the manufacturing process must be adapted. Poor documentation means having to discern informal changes for future revisions, which becomes especially troublesome if production is taken to another manufacturer.
- End-customer returns. Technically, issues could arise due to poor design choices, but the manufacturer must submit boards to extensive testing to detect failure vectors. Before the boards are fit to leave the shop, designers must have confidence that they have been exhaustively probed and analyzed to minimize end-user frustration.
- Poor documentation practices. As previously alluded, poor documentation can make working with multiple manufacturers a headache. However, it is still far from ideal, even when working with a single shop. Documentation acts as a checkpoint in design, allowing future revisions and layout teams to quickly and accurately resume where others have left off without skipping a beat. Fully-updated design documentation is crucial to maintaining the link between past and future board iterations.
- Excessive respins. Sometimes design changes are completely out of the hands of the manufacturer. For example, designers may request or eliminate features and functionality, or suppliers may be experiencing component or material shortages. Even then, some manufacturing changes are unforeseeable and will dictate a redesign. Still, when it comes time for a manufacturer to review a design, designers should expect a comprehensive report incorporating as many DFM principles and changes as possible. Beware of the “Whack-A-Mole” manufacturing method, where poor practices are being resolved post-production rather than circumvented before fabrication and assembly.
- Incompatible CAD tools/databases. Outdated or legacy software may lack standard design features and compatibility with common industry suites. Translating documents and files can take time and introduce errors at the initial design stages.
Problems like these can be avoided by choosing to partner with a CM that provides the level of quality necessary for a successful build. Not only do manufacturing and testing capabilities need to be top-notch, but they should also aim to reduce the number of re-spins for a product in the development stage. Minimizing the number of redesigns will save money and time, allowing designers to bring products to market sooner than a less experienced or rigorous assembly shop.
The Best PCB Assembly Services Are Proactive, Not Reactive
To avoid the above pitfalls and contribute to your project’s success. A CM should be adequately staffed with trained personnel to work with you on perfecting your design before it reaches manufacturing. When evaluating a CM, ask questions about their processes, quality, and service, and establish criteria to qualify them at an early stage of product development.
Many CMs also welcome facility visits to build an in-person rapport; designers should take advantage of these walkthroughs to minimize the production cycle time. Designers can facilitate a smooth manufacturing workflow by asking a CM about some core practices:
- Component analysis. CMs need a methodology for tracking obsolete components in a bill of materials (BOM) or components that have otherwise been depreciated. Especially with component shortages resulting from pandemic-related shutdowns, the ability of a CM to replace, source, and procure alternate components quickly can be the difference between meeting production schedules or waiting for part resupplies.
- Design for manufacturability (DFM) review. Any features that endanger the manufacturability of the board will require engineering resources to resolve. Implementing DFM may even include having the CM make corrections while maintaining the design intent of the board.
- Design for test (DFT) review. As with DFM, a CM should be able to review designs for testability and make recommendations for corrections. Additionally, DFT rests on the ability of the manufacturer to design and program test fixtures.
The baseline expectation for a competent CM is a fully defined assembly process from start to finish. This method would include everything from component placement through soldering. Supporting processes such as quality control and inspection points throughout manufacturing act as flags for potential defects. Once assembly is complete, a design will undergo thorough testing. Testing services should be fully defined to ensure complete inspection of the PCB, from ICT and flying probe to a full functional test.
Your Contract Manufacturer Bests Even the Highest Expectations
The best PCB assembly services sprout from two-way communication and accommodation of the design intent while maximizing producibility and minimizing cost. A CM’s goal should be to deliver an assembled board back at the highest level of quality possible. That means collaborating closely throughout the manufacturing lifecycle of a project and running BOM, DFM, and DFT scrubbing evaluations to optimize designs for production while meeting all form, fit, and function requirements.
At VSE, we’re a team of engineers committed to building electronics across many life-saving and life-changing industries for our customers. Working closely with our valued manufacturing partners, we endeavor to realize your NPI or large production volume goals.