The Sink marks estimate and Sink marks shaded results display simulated sink marks on the part. These are two different visual interpretations of the same result.
The Sink marks estimate result displays the calculated depths of sink marks in the part and provides a legend to interpret the depth differences.
The Sink marks shaded result displays the sink marks on the model to represent how the part will actually look, as shown in the following diagram.
These sink mark results indicate the presence and location of sink marks and voids likely to be caused by features on the opposite face of the surface. Sink marks typically occur in moldings with thicker sections, or at locations opposite ribs, bosses, or internal fillets. These results do not indicate sink marks caused by locally thick regions.
Note Although the result cannot predict whether a sink mark or a void has occurred, sink marks are the more likely option.
Using this result
Because sink marks are a visual defect rather than a structural defect, the result should be evaluated against the part's visual design specifications. Lighter colors and textured surfaces tend to make sink marks less visible.
Generally, if the thickness of the rib is less than or equal to 60 percent of the main wall section, there is not likely to be any significant sink marks.
If it is not possible to remove or reduce a sink mark, you can conceal it. This can be done by adding a design feature, such as a series of serrations on the area where it occurs.
Things to look for
The following solutions can reduce the occurrence of sink marks:
- Alter the part design to avoid thick sections and reduce the thickness of any features that intersect with the main surface.
- Relocate the gate to or near the problem areas. This enables these sections to be packed before the thinner sections between the gate and the problem areas freeze.
- Increase the size of gates and runners to delay the gate freeze-off time. This enables more material to be packed into the cavity.
- Decreasing the melt and mold temperature may be sufficient. Alternatively, a less viscous melt can be used.
Because sink marks occur during packing, the most effective way to reduce or eliminate them is to control the packing pressure correctly. Use a more comprehensive simulation package such as Autodesk Simulation Moldflow Insight
, to determine the effects of packing on sink marks.