Surface offset issues

[magneplanar]

MCAD Pro's,

If you are offsetting a surface and find that you
can't offset to the thickness required for the entire shape. (shell
failed miserably unless I controlled the x,y,z) Is it better to:
A) offset part of the surface that does work and try to build in the gaps?
B) Redraw the curve feature that frames the surface at an offset value?
C) Pass the project to another engineer and make bad comments about the ID firm.
D) other...

had
this issue awhile back and ended up letting the mold makers tool remove
the undercut by thickening the part at that area in the mold. Just
thinking about how I would do it if I could do it again. I am not able
to show the model so I hope I have described it well enough without.

cheers...

M

 

[mgnt8]

Are you trying to get a solid? Then, unless its too much time, just build the entire watertight quilt. However, I don't mind myself thickening up parts of the wall if your not talking about no more than 30% or so. Of course, the molders might have another opinion.

 

[magneplanar]

mgnt8,

the goal was a solid, of a specified thickness, for an LCD housing. I could offset about 40% of the upper section, the lower section was a complicated pinched sweep that had undercuts on both sides. The offset of that surface did not come close to matching the 40%. Shifting the datum curves caused surface failure so I was not able to pull it in. I ended up splitting the mold sideways with sliders and had a parting line perpendicular to the split.

I did rebuild the lower section with new curves offset from the outer set to get the desired thickness. It just seemed like a hack job of it. Ran out of time to finish the complete surface build for the inside so I built patches.

an early project that I am reworking for fun just to see if I have learned anything since then. Head mold maker said the ID model was no good but I had to work with it since it was a big customer. In the end, only the inside had issues in the off tool.

M

 

[Zaki]

Hi Magneplanar


could u post ur part here? if so, I can check it and make possible solutions. Always remember some things when u r going to surface modeling. 1,make surface with minimum patches as it is possible. 2, consider general rules for thickning or offsetting, that no portion will lost in offseting or become zero. 3, sometimes a very small portion, or a portion that becomes zero slightly make a mess and cause troubles in thicknening or mold splitting. 4, dont make extremely high curvature surfaces.


If it is possible to u to upload here, plz do it.