More surfacing questions
More surfacing questions
(OP)
Finally making some progress in the vacuum formed part I mentioned in thread562-258988: Help with 'draft' in surfacing.
I have an external shape for the base part but I'm having trouble thin walling it to the correct thickness. I need .125 and can only get .068. I get the error message "Thinwall failed. The faces contain a curvature which is smaller than the offset distance" which would be fine but the radii are a lot bigger than the thickness.
Any ideas?
Rather than a thinwall do you think creating an inner surface would be more successful and doing a boolean?
I'd post the model but it was too big when I tried before. Here's a jpeg though.
http:/ /files.eng ineering.c om/downloa d.aspx?fol der=5cf7d1 99-afaf-41 00-a736-99 701bdd27cb &file= thinwall-p roblem.JPG
Any help appreciated.
I have an external shape for the base part but I'm having trouble thin walling it to the correct thickness. I need .125 and can only get .068. I get the error message "Thinwall failed. The faces contain a curvature which is smaller than the offset distance" which would be fine but the radii are a lot bigger than the thickness.
Any ideas?
Rather than a thinwall do you think creating an inner surface would be more successful and doing a boolean?
I'd post the model but it was too big when I tried before. Here's a jpeg though.
http:/
Any help appreciated.
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What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?





RE: More surfacing questions
Try offsetting the surfaces highlighted individually - if that works you know they aren't really the problem.
Do you have small fillets where some of these sufaces join?
If so that could be the problem.
bc.
2.4GHz Core2 Quad, 4GB RAM,
Quadro FX4600.
RE: More surfacing questions
I offset the individual faces using 'Offset Surface' and they all offset however...
They all split into multiple surfaces and the front & rear corners 'bubbled'.
Looking in the tree, all except the little 'sliver' are offset from surfaces created from variable radius rounds. As memory serves I had to use variable radius even though I use a single radii value.
I'd already looked at the small fillets and don't think that's the issue, I went back in the tree and tried doing a thinwall before adding them and there were more problem surfaces highlighted when it failed.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: More surfacing questions
http:/
Also, to say thanks and if anyone has any more input, it's appreciated.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: More surfacing questions
Which side of your model will be used to cut the tool? Is it a male tool using the inside surfaces or a female tool using the outside surfaces? Those are the surfaces that will really make the part and have to be perfect. The other surfaces are only used in your model. This is because in the real part they made by the sheet and the thickness will not be perfectly uniform. Did I explain that well?
That said the accuracy of the other surfaces can be reduced. So if something does not offset well you can delete the bad part and model it in a way that works. This might give you non uniform wall thicknesses.
NOTE: if you are using a two sided model such as an injection molded part than both sides must be perfect. Also uniform wall thickness is very important for the molding process.
RE: More surfacing questions
I'm just showing one of 5 'parts' that go together to form finished article. It's a bit of a russian doll situation with molded in liners which is why I'm modelling from the outside in as it were. Also it has a access cover that closes up the opening.
It will actually be a male mold for this part so yes the internal surfaces are arguably more important from that point of view. I fully understand what you mean and have been trying to keep the essence of that in mind when modelling, though maybe I've missed some nuance.
Also, this is a very aesthetic part and everyone upto the division VP wants to give input on it. It started out as a very simple shape based around suiting the manufacturing process then we had to get an industrial designer look at it and now it's more complex, though admittedly prettier.
I have a rough external outline model from the industrial designer (made in SW and I only have a step of it) but it has been modelled without really taking account of some of the finer details of the manufacturing method.
So I'm basically trying to take the ID pretty design combining it with some changes requested by the VP and address manufacturability.
Thanks for the help.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: More surfacing questions
I would model the male surfaces first on the next part. That will be easier anyway because most of the offsets will get bigger.
If the outside surfaces will be textured or smooth or painted makes big differences in the details of the model. The flow of one surface into another or the rounds is more important with a painted part.
RE: More surfacing questions
Alternatively, use a surface by boundaries and I think you can get tangenciy with the surrounding surfaces.
bc.
2.4GHz Core2 Quad, 4GB RAM,
Quadro FX4600.
RE: More surfacing questions
The part will be painted to look similar to covers on other tools.
The way the part is shaped, to fit it's eventual 'contents' it's conceptually simpler (at least for me) to model the exterior surfaces first. However, if I can't crack the nut that way I'll have to try the opposite approach.
I replaced wobbly surfaces on some of the earlier face offsets. If I can't get the thin wall to eventually work then this was the approach I was looking at but thanks for confirming my thoughts.
Thanks both of you, just to further complicate things my manager just came by all excited about the EM sheilding of it.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?