Why a dimension can move after machining
Temperature, moisture, residual stress and workholding can affect final dimensions. Thermal expansion and low stiffness make the measurement and stabilization conditions part of the task.
A practical drawing and supplier brief
Record the full grade/filler, stock form and orientation, feature dimensions, restraint during machining, any agreed stress-relief treatment, stabilization time, temperature/humidity and measurement method. Agree the limits for that state.
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A nylon part measured immediately after machining and one conditioned in service humidity are different dimensional states. Do not use a generic ± table or unrelated ASTM method name as proof that both will meet a limit.
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Sources and review scope
Reviewed 23 October 2026. Arithmetic examples are labelled separately from source-table facts and standard scope.
Ensinger machining FAQ
Machining, moisture, stress relief and workholding conditions; does not establish universal achievable tolerances by generic polymer name.
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