6 Criteria for Choosing an EMS Provider, Part 2

(In the first of two parts, 6 Criteria for Choosing an EMS Provider, Part 1, I focused on the importance of price, location, and production volume. Here, we wrap it up with three more key criteria).

4. Technical capabilities: Most obvious are the PCB assembly capabilities. As we discussed in an earlier post, look at the company's pick-and-place lines, and ask about their current projects to assess whether they have the ability and experience to handle components with the smallest size or pitch that you use on your boards.

Look for sophistication in other processes you need, such as conformal coating, testing, and inspection. Any manufacturer can provide expensive test fixtures for high-value products or volumes of 100K+ per year. If yours is a lower-volume job, assess your partner's ability to develop effective, low-cost test fixtures for the project.

Look at how the EMS provider uses automated optical inspection. Many use it only for detecting missing parts. Modern AOI is much better than that, if skillfully programmed and maintained. It identifies wrong or misaligned components, bent leads, defective solder connections, and more. Paperless defect tracking can speed rework, and drive continuous improvement of manufacturing processes.

5. In-house design capability: Some OEMs know they need design help. These include firms with product ideas but no full-time electronics engineers. For these companies, choosing an EMS partner with a strong in-house design team offers significant advantages over hiring a separate design firm.

The EMS provider's in-house design team will understand their shop's manufacturing processes and capabilities, giving you designs with better manufacturability and often lower cost. The designer engineers can walk down the hall to shepherd their prototypes into pre-production.

Any manufacturing issues will be the undisputed responsibility of the EMS partner -- you won't waste time trying figure out whether it's a design problem or a manufacturing issue and which of your vendors is responsible for fixing it.

Even OEMs with full engineering departments benefit from working with an EMS partner that has an in-house design team. The Z-AXIS design team routinely reviews customer product designs before going into production, and can almost always recommend ways to improve performance, reduce costs, and eliminate potential manufacturing problems.

6. Culture: Not usually on any checklist, but definitely part of the decision process, is the EMS provider's company culture. By this I mean the priorities that drive everything from management business decisions to the individual employees' actions. Are the people you talk to focused on their own internal policies and rules, or on your needs? You can gauge this during the RFP process. A few clues include:

• Do they respond promptly to you, or are they busy with other priorities?


• If they respond quickly, have they taken the time to make sure you understand each other? A quick answer is great, but only if it fully addresses your real concerns.


• Do they listen to what you need, and find ways to deliver it? Or do they spend all their time telling you what they do and expect you to adjust to their model?

Obviously, there are many other factors, and we will address more of them in future posts. Meanwhile, IPC has some additional resources on this topic. They include a free download "How to Begin the Process of Selecting an EMS Provider." It was published in 2005, but its guidance is fairly timeless.

The IPC also offers IPC-1720A (a Word document download), a checklist you can use to gather information helpful in evaluating or auditing an EMS partner's capabilities. It's an extremely detailed checklist, though, so use it wisely and avoid wasting everyone's time gathering information that you won't use in your decision process.