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38 SMT007 MAGAZINE I JANUARY 2024 defects but is an active part of quality manage- ment in preventing defects. In some cases, as the rate of defects lowers, it may become more cost-effective to scrap defective units rather than repair or rework them, while building extra units into the work order to compensate. is is the state of the art for many, but not per- fect, certainly in terms of material waste. In most cases, defective products will need rework at some point, so you must prepare. But the cost of skilled engineers does not decrease with the reduced number of defects. Instead, these key people have more free time and it's challenging to utilize them effectively as other jobs in manufacturing don't require their spe- cific skills. When there's not enough work to do, engineers become bored and search else- where for challenges. at's when you need to look for a new solution. What We Can Learn Most of us today have grown to value the data in manufacturing in terms of how to understand the root causes of inspec- tion and test failures, and help resolve weaknesses in manufacturing processes, including material choices and handling. Learning from repair and rework is our final oppor- tunity in manufacturing to gain a higher-level under- standing of the health of the product design and pro- duction process. Though the de s ig n pa s s e s tr adi- tional design-rule checks, conditions remain that may be sensitive to the effects of variation and simple mistakes. Subtle changes in design may avoid creat- ing those conditions. Intelligence is required to expose design improvement opportunities, going well beyond the root causes of specific defects. Such determinations depend on com- plex contributors, for example, the capabilities of machines and manual processes, not just to execute the assigned work, but to under- stand how "comfortable" the work is. is can be quantified and measured, for example, by the amount of variation created in product completions, which increases as machines are pushed to their limits. Some machines may place a certain compo- nent with ease, while another struggles. e mix of material sourcing for a specific component also plays its part, as slight deviations in shape and size from different vendors, or even differ- ent lots, become significant in terms of a cause for the variation. In times like these, where supply is constrained, there is a strong likeli- hood that materials selected and purchased may not match the original design intent. Whether such variation implies a problem or is a benign function of the material change, requires intelligence to assess. Many analyses differentiate the responsibilities of manufac- turing operations, machine or operator perfor- mance, design, or material-influenced varia- tion. Association and analysis of such variation in turn helps improve design, manufactur- ing planning, machine selec- tion, material purchasing, and more. It has been proven statis- tically that reliability rates for products in the market are directly related to defect opportunities in manufactur- ing. e dwindling opportu- nities for feedback from repair and rework in manufacturing, therefore, represent only the start of this opportunity. In today's design-for-demand driven econ- omy, repairability is not a high priority. Prod- ucts under warranty are simply replaced or a major component is swapped out. Beyond that, the product is usually discarded. Very lit- tle effort goes into troubleshooting what actu- ally failed. Information about unknown and In most cases, defective products will need rework at some point, so you must prepare.