Get the right stencil for the job.

This month we illustrate an example of what appears at first glance to be poor lead solderability. When examined, however, it is a combination of component and pad design.

FIGURE 1 shows the lead to be floating in the solder joint, suggesting poor wetting. When we examine the component lead and plastic body, however, the lead is not parallel, so it always sits off the pad surface, even if perfectly soldered. The lead sits in a cavity in the component body to maintain its position. But with the size of the pad used in the design and a full solder paste print, the component body will always lift.

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So rampant was coronavirus, it even infected accounting systems.

Day 1: Today the authorities announced local shelter-in-place restrictions. All employees of nonessential businesses must stay home or be subject to fines if caught at the workplace. What to do? Set priorities: define whether we are essential and be prepared to back it up if we are. There is no Essential Business Department in California, like the DMV, to which one can apply and get a Certification of Essentiality. No tests one takes. It depends on one’s OEM customers and flows down to their suppliers. For those of us not named Elon Musk, we are not a law unto ourselves.

Day 2: Met with the crew. Game plan time. Henceforth, the old guys (the “over 60s”) will stay home. That includes (gulp) me. Aging and mortality in one poignant bite. A small crew will remain at our facility, handling day-to-day essential business. (In the preceding 24 hours, we established our corporate essential bonafides.) Headcount will fluctuate daily, depending on happenings. Some will stay home today; others will do likewise tomorrow. I stay home every day pondering the Darwinian way of the world, and my humbling new lot in life as a high medical risk individual. Regardless of work site, all employees will continue to be paid for the foreseeable future. As if we can foresee it. No one will burn PTO if they must stay home. Engineering work will be conducted from home to the extent possible. No onsite customer visits will be allowed until further notice. Living a paradox: keeping it all together, while dispersed. Here we are.

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A walkthrough shows why you can’t “guess” success.

When a customer learns their much-needed PCB job has inexplicably gone into the dreaded “hold” basket, the instinctive response is indignation. Let’s take a moment to examine the possible reasons. After all, the fabricator doesn’t want an unhappy customer, nor a pause in work volume. Yet, a great deal of precise data is needed to build a printed circuit board. As layer count and complexity increase, so does the volume of correct information needed by the fabricator to properly manufacture the job. If some necessary data are missing, the CAM operator will hand the file back to sales to sort out the problems.

The one steadfast rule all PCB manufacturing facilities hold dear is “we don’t guess.” Never. Break that rule and the consequences will bite back hard. To ensure no one is guessing, every question must be answered. If you failed to specify a tolerance on a set of holes, the job will go on temporary hold until the CAM operator can get a suitable answer. If you have an electrical short between ground power layers due to a misplaced via, the job goes back to sales to sort out. When a job is on hold for a serious problem, the result can be days of delay. If there are one or two small issues, however, in many instances the CAM operator or sales will call and sort it out. They might be able to move a trace or two to prevent a short, for example, or change a pad size to correct a problem with an annual ring that is too small. However, the CAM operator must meet a quota of jobs each day to keep the manufacturing facility fully loaded. They do not have an abundance of time to fix a multitude of problems in an individual customer’s data. Other jobs are waiting! In that case, the CAM operator hands the file back to sales to reject the data. The customer can then fix it and resubmit it through the whole process of price quote, DRC (design rule check) and setup.

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System strategies and the visual factory can handle rapid changes in demand.

Supply-chain disruption and Lean philosophy rarely go hand-in-hand. In some cases, however, systems created to support Lean manufacturing or principles themselves help mitigate the chaos the pandemic has created in the global supply chain.

SigmaTron has operations in the US, Mexico, China and Vietnam. As a result, we had a bird’s-eye view of the initial impact on manufacturing operations in China and used that as a roadmap for preparing operations in other locations for disruption, along with best in-plant practices for disease mitigation. While the ways different jurisdictions reacted to Covid-19 varied, the issues were somewhat similar. This column looks at some lessons learned in that process from this contract manufacturer’s perspective.

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