Sink Mark Issue.

[Anonymous]

Sink Mark on Curvature Surface 1.0 Sink Mark could be found on opposite side of Curvature Surface (Ball Shell) rib area. Using smartscope and shown sink around 0.07mm. 2.0 Material used: PP+ 30% GF. 3.0 Injection parameter, holding pressure, cooling time, mold temp, melt temp base on machine setting. 4.0 Gate, Runner, Sprue size base on tooling dimension. 5.0 Fiber orientation (transverse) setting been confirmed. Sink Mark could not been found in Moldflow simulation but if could been seen in off tool part. Purposely lower down the Pressure (Machine, holding) and reduce the tonne, holding time but sink mark not been found. Run in Dual Domain & also 3D. Please advice. Ncu.

[raalteh]

Hi,

I have little information to go by. I have to assume you are using the Moldflow 2011 release, which should have sink mark capabilities in Dual Domain and 3D.

There is some sensitivity to the mesh in the area where the sink mark is occurring. If the part is truly bulky in the area where the sink mark is occurring, it is possible the sink mark gets missed. The current sink mark solver is intended to flag sink marks at the back of ribs, and the mesh quality in that area is a factor in how well it can detect the sink mark.

Some screen shots of your model (mesh) would do a long way.

Hanno

[Anonymous]

Hi Hanno, 

Yes, Moldflow 2011 release was used and simulation was run in Dual Domain & 3D.

Edge Length at that area was set to 0.9. Mesh match percentage is not good at rib area due to curvature surface. 3D should do not have mesh match percentage concern but sink mark still can’t be found.

Please could you let me know the “mesh quality” in your previous email refer to edge length ,mesh match percentage or other?

Thanks.

[Anonymous]

Hi Hanno,

Further simulatino was set up.

If the Ribs are perpendicular with curvature surface & sink mark could be found. Software might not recognize if the ribs not perpendicular with the surface.

I assume that is related with the sink mark equation used behind the software.

Regards,

Ncu.