SW mold tools - knitting surfaces

Does anyone have any advise or resources for help with troublesome
knitting of surfaces? I am really struggling to get surfaces to knit
when using SW mold tools. Is there a way to adjust tolerances or
tighten gaps??

Any advise would be helpful.

-JOSH

 

I personally have not had good success with the SW mold tools. I think
for anything but the most basic shapes you wind up doing most of the
work manually anyway.

Problems with knit could be just about anything, but what I do to
troubleshoot knits is to knit faces that will knit, and increase the
scope of the knit until you find a face or a group of faces that will
not knit. Look for anything questionable. Try to recreate the problem
face(s) with an alternate method. Don't count on radiate, extend or
ruled surface features, they will frequently create overlaps, sliver
gaps or other strange geometry.

 

I recently had a surface model that also wouldnt totally knit. I saved
it out as a Parasolid (.X_T), and then opened it up in SW again. When
I opened it, import diagnostics was now an option. Using it, I was
able to see where the gaps were in my surfaces.

Note that once to create any feature after importing the model, Import
Diagnostics is no longer available, so make sure you know where all
your gaps are before you add ANY feature. You can try to use the
"attempt To Heal All" feature, but im sure most surface people on here
will tell you it rarely works.

Im with Matt on this one, I have not had much success with SW mold
tools, and it will be easier to fix yourself.

As far as tolerance of gaps, I dont know of a way to tell SW to allow
gaps of a certain amount.

 

Thanks for the advise guys. I actually already did what you said
("saved it out as a Parasolid (.X_T), and then opened it up in SW
again"...). The import diagnostics, while not automatically, did allow
me to get to valid surfaces/solids. I ended up doing this for both my
core and cavity mold halves. Unfortunately, this work-around leaves me
with an unparametric mold, which has no references to the original
model where I had defined shrink rate, parting line, etc. Hopefully I
won't need to change any of this. Aside from this troublesome part, I
have had fairly good luck with SW mold tools so long as the part
geometry (often imported from the client) is decent to start with.

Can anybody suggest further advise or reading on this topic??

Thanks,

-JOSH

 

Even if you import something, you can still update it. When you get a
new exported part in parasolid, just RMB on the old imported feature in
the solidWorks part and select "Edit feature", and it will let you
select a new import file, and will update your solid. There may be
problems if you have any child features created from the original
imported solid, but it's better than starting over.

In general, there is probably some better solution to your problem than
exporting and reimporting. I try to always overbuild surfaces and then
trim back, using mutual trim if possible. If that isn't available, then
I will try to use the model edges directly that it has to align with. I
try to avoid using indirect data to try to match an edge, there are just
too many things that can go wrong (making a surface from a projected
curve made from converted 2D sketches).

Beyond that, I like to use SplitWorks to split cavity/core because it is
far more capable than the built in tools in SW.

 

Thanks for the additional tips Matt!

-JOSH

 

I have done several vacuum form molds using the mold tools. Some of
these molds had a fairly complex parting line. The mold tools in SW
saved me on several occations. The only thing I had trouble with was
the shut-off surfaces. I ended up doing those manually. However,
anytime I had trouble knitting surfaces, I used -Tools-Check- and
selected surfaces. It points out where any problems are in the
surface. I could fix those problems and make the knitting work.