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Mom was right; it's easier to clean up as you go along.

No one wants to stop playing to clean up their toys, but we all remember our parents' sage advice: "If you just take the time to pick up as you go along, tidying up won't be such an overwhelming task." Mom was right.

The same holds true for electronics manufacturing. Periodic process assessments can help alleviate potentially monumental problems. The longer the problem persists, the more it will impact the bottom line and product quality. Conceptually and practically, process audits are not new. Establishing what is wrong and right about a process or a line is a good starting point. But by taking it a step further, putting a detailed plan of corrective action in place and illustrating what the plan's end-result will be, manufacturers can attain their goals: more good boards, and better results for the bottom line.

For pre-placement, a process audit methodology makes the report simple and easy to use, with each subject of the report graded on a beacon scenario (Figure 1). The goal, of course, is to minimize the total cost per printed board. In our assessment, several factors of pre-placement are evaluated:

• Solder paste.
• Stencils.
• Boards.
• Squeegee or print head.
• Tooling.
• Print parameters.
• Environment.
• Process.
• Inspection data.
• Operator training.

Within each of these elements many areas are observed and analyzed, therefore a full view of the process is established. We understand how demanding an engineer's role has become and, because of the enormous amount of tasks at hand it is often difficult for the engineer to see the forest for the trees. This is where an independent expert can provide value and bring to light underlying process issues.

Various parameters of each of the aforementioned areas are evaluated in depth and assigned a grade based on the beacon scenario. Then, improvement recommendations are made for every item that needs corrective action; this is where the value of dedicated expertise and a broad knowledge of the print process really become a true aid to the customer.

Finally, for each item, the improvement potential is illustrated as follows: T = throughput, E = effective printed boards and C = cost (Figure 2). In other words, if the manufacturer implements the recommended correction, there could be opportunities to improve throughput, effective printed boards or cost. The report contains the observations from the audit but the results are condensed into a one-page executive summary, permitting a quick view at which elements of the process require resources.

It is also important to establish a baseline for your audit so that improvements can be effectively measured and tracked as they are implemented (Figures 3 and 4). DEK's minimum recommendation is a quarterly pre-placement process evaluation. In fact, baselining a process before any major changes are implemented is a useful exercise because it means a data-driven decision on the success of the implementation can be made. Pb-free processing makes these audits more imperative.

But, the audits need not be all-encompassing. Our goal is to make this a simple, easy-to-understand, visual tool for manufacturers to quickly see where the process might be out of control, how they can correct problems and what results (throughput, effective printed boards or cost) can be realized by following the 10-point plan. Regular process audits are cost-effective, with most companies reporting a 100% return on investment within a month.

So, remember the hard lessons you learned as a child, implement process audits and "clean up your toys as you go along." In our business, the payback can be huge.

Clive Ashmore is global applied process engineering manager at DEK (dek.com). His column appears semimonthly.

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