Surface Offset for mold
Surface Offset for mold
(OP)
I mentioned in an earlier thread that I'm somewhat new to surfacing.
I have a finished part that was created with complex surfacing, I can not change it.
Now, I have offset these surfaces inside to create a mandrel for molding. The complex surfaces don't like to offset very well. Per the pic you see some surfaces are not smooth and there are gaps where the final part has radii.
Are there other methods besides using offsets to create molds for the internal geometry of the part, or how can I fill these gaps? I tried all surface commands like boundary, filled, etc, none work.
I prefer to not use offsets because there are too many surfaces and too many additional steps to fix the offset's overlapping surfaces.
The dark areas are the gaps I need to fill between the 'stepped' surfaces.
I have a finished part that was created with complex surfacing, I can not change it.
Now, I have offset these surfaces inside to create a mandrel for molding. The complex surfaces don't like to offset very well. Per the pic you see some surfaces are not smooth and there are gaps where the final part has radii.
Are there other methods besides using offsets to create molds for the internal geometry of the part, or how can I fill these gaps? I tried all surface commands like boundary, filled, etc, none work.
I prefer to not use offsets because there are too many surfaces and too many additional steps to fix the offset's overlapping surfaces.
The dark areas are the gaps I need to fill between the 'stepped' surfaces.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion






RE: Surface Offset for mold
RE: Surface Offset for mold
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Surface Offset for mold
RE: Surface Offset for mold
Looks like there's a little crud from surfaces not being well-knit. Or is that just the picture? You may end up needing to offset the surfaces individually and extending/ trimming/ knitting them.
RE: Surface Offset for mold
I tried scaling the model, does not work. Scaling will not be proportional overall. I have to offset, then add material to the length for shrinkage.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Surface Offset for mold
If the whole thing isn't scaled, perhaps you can identify areas that are scaled. Separate your model into chunks (solid bodies) by splitting, scale the chunks you can scale, and then join the bodies again. A bit of a hack, but it might work fine, depending on your limitations of scaling.
Jeff Mowry
www.industrialdesignhaus.com
A people governed by fear cannot value freedom.
RE: Surface Offset for mold
Thanks for the help.
I'm going to have to fake and redo some of the parts.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Surface Offset for mold
This is especially true with iges where everything comes in NURBS and much of the tangency is lost, I always try and avoid iges if at all possible. Again if the part is modelled a long way from carline this does not help, tweaking the settings can improve this.
If you start of with bad data the problems just get more and more as you try to offset, it is well worth spending some time up front fixing the data it will save you hours down the road. Not to bad on a simple part like the one shown but a real nightmare on anything complicated.
RE: Surface Offset for mold
I have to fudge it somehow. Thanks!
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Surface Offset for mold
RE: Surface Offset for mold
I'm stuck.
Thanks anyway.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Surface Offset for mold
You might try doing a Delete Face with Tangency or Boundary Patch. If neither of those work Filled or Boundary Surface can maintain Tangency and Curvature conditions on boundaries.
It may be impossible or be hard to come close to their crappy model But you can make a 0 distance Surface Offset (copy) feature of the original surface prior to the Delete Face command so you can compare the geometries using SolidWorks Utilities.
Other options.
Get a 3D Print made and sand it down and scan it.
Michael
RE: Surface Offset for mold
best way is to have a robust contiguous model first, scale, offset surfaces 0, build other surfaces, trim, knit into solid(s).
Sorry if that doesn't work for you. As you know there are many ways to do same thing, so try again to achieve above result.
Regardless, in Solidworks surfacing, I have resolved to default offset surfaces 0, extend them, frequently individually, beyond required dimension to intersect other offset or built surfaces, then trim and knit to solid.
I have noticed a persistent bug in Solidworks Surface-Extend: frequently it extends linear and contiguous tangent curved surfaces illogically. Delete and try again (not edit existing) works, extending contiguous tangent surfaces evenly.
Surface-Extend up to surface rarely works; always extend beyond to intersect, trim, etc.
If I build a sketch driven surface its dimensions will always be beyond what is required, then trim, knit, etc.
Solidworks surfaces love to orphan themselves like a suicidal cult from their parent child relationship. This is why I repeat others in first statement - best to have robust valid model, scale, offset 0, etc.
If you haven't worked a lot with Solidworks surfaces expect to have the feature tree grow exponentially. Grouping like features into folders, coloring surfaces differently, regularly turning on/off surface / solid bodies - all common.
RE: Surface Offset for mold
I have tried all of those commands. The 0 offset first is a good idea, thanks.
pierdesign,
I have been grouping them into folders because there are a lot. Thank for the suggestion.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion