Sink & Knitlines

We work with our customers to try to minimize sink and knitlines during our DFM process. 

  • Sink (a physical depression on the surface of a part) frequently occurs around thicker sections. If the rib is the same thickness as the wall, the intersection of the two creates a localized thick wall and is susceptible to sink
  • Decreasing the thickness of the supporting rib eliminates or reduces the potential for sinks. Generally, the thickness of the rib should be about 75% of the thickness of the wall
  • Knitlines can occur when two flow paths or material meet in the cavity and when the flow path is relatively long
  • Visually, negligible knitlines on properly designed MIM parts are superficial and do not represent a structural defect or part performance issue. Generally, knitlines of this type have a shallow witness that is as little as .0005” deep to .005” deep

 

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Last updated 11.27.2019