Even micro flaws can become a big deal.


Standard deviation exists in every single project. The two by fours framing out your new kitchen all vary in length to a small degree. It is minuscule (hopefully) but it is present. The same is true in manufacturing. Producing the highest quality part requires understanding any potential flaws that could affect their application, major or minor. These details should be a part of the design for micro molding (DfMM) process at the beginning of every project.

Design for Micro Molding (DfMM) Process

There is no limit on how accurate one can mold something, and we often reach out to customers for an interpretation to ensure we are not in violation of the drawing. Our level of precision micro molding can sometimes account to three or four levels past the decimal point. This is why understanding the tolerance requirements before any steel is cut is paramount.

Our customers’ parts are complex with tight tolerances. In some cases, the actual performance of the process requires a second conversation about what may be acceptable or not. Theoretically, if there is a flash callout of 0.001” on a part but a run of 20K parts actually measure 0.002” that is a big deal. In these rare cases, we would quarantine those parts and reach out to the customer with a deviation or interpretation request to increase the flash callout in this area.

If the customer agrees the flash is acceptable, we move forward. This is rarely a problem because our deviation standards almost always exceed the customer’s expectations. However, clearly understanding how much deviation is acceptable in advance via our design for micro molding process is key for faster and more robust production processes. 

When Standard Deviation Affects “Form-Fit-Function”

Sometimes there are questions as to why we would want to know about the full-assembly, including parts that may not be molded. This is to ensure the best possible approach to molding one component fits well in the full context of the project.

Therefore, our team incorporates proactive steps to help identify potential defects during FOT, DOE, OQ/PQ runs. This attention to the details will help address some of the uncertainty.

If deviation impacts “form-fit-function” it is best to know that at the beginning of a project during the design for micro molding phase. Understanding what deviation is not standard, or even how potential defects (major or minor) would impact their application, ensures the production phase is not interrupted. In these cases, the production team has a better understanding of the acceptance criteria and would not have to react after steel is cut and parts have been made. 

Three Major Defect Categories We Watch For

Considering the three main categories of defects (minor, major, and critical) We ask customers to identify, address, and break down each one to help us understand their expectations up front in our design for micro molding. Minor defects may not seem as important in earlier discussions, but clarifying this area avoids communication delays on the manufacturing floor.

Removing all uncertainty reduces unnecessary tooling repairs, eliminates extra phone calls to customers for answers, prevents project stalling, and most importantly, keeps customers happy. 

Brian Daniels

Brian Daniels is the Small Mold Production Manager for Accumold. He has over 20 years of management experience in fast-paced high volume manufacturing environments. People, quality, and customer satisfaction remain his top priorities.

micromolding components next to EU coins.

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