Design of experiments or DOEs represent a recent advancement in the continuing challenge for achieving highly reliable medical electronics PCBs.
DOEs extend well beyond the extensive nature of a PCB cleaning process. That means DOE practices and procedures focus on investigating and resolving out of the ordinary problems. These are unforeseen and difficult to define PCB design/layout, fabrication, and assembly issues.
These unpredictable and quite unexpected problematic areas usually cause the OEM to abandon a costly PCB investment simply because the EMS Provider cannot locate and define a particular issue.
Check out our Medical Design Briefs Magazine article to get a more comprehensive look at DOEs and how they’re resolving difficult problems.
Meanwhile, here are some tips and hints that’ll help you to help salvage a costly PCB by first thoroughly investigating a difficult problem.
- Take a step back when an unexpected problem occurs. If the problem is due to insufficiently clean sub-assembly circuits, you and the EMS provider must engage in closer collaboration.
- Infinitesimally small areas on a flex circuit demand special cleaning processes. Example: Fig. 1 shows bubbles created on a medical electronics ultra-high frequency flex circuit. Flux creepage or water penetrated through the flex circuit to create those bubbles during assembly.
- Special cleaning processes for medical electronics PCBs have target requirements. Check your EMS provider to learn more.
- A six or more step-by-step strategy is used in a DOE to arrive at a satisfactory solution.
- DOE solutions are based on special EMS provider in-house methodologies and techniques.
- Generally, small-to-medium EMS companies are best equipped and experienced to create those critical DOEs.
Persistence is the linchpin for accomplishing successful DOEs. The understanding between EMS provider and OEM in these instances is the fact the project at hand is floating in unchartered waters. All the answers aren’t there. But the critical ingredients are available, and those are tenacity, knowledge, basic information, and some idea of the direction that needs to be taken.