I have a problem with a swept cut along a spiral.
Essentially I am making a 1/4-20 thread with an actual cut (I know that isn’t the common way to do it). The thread length in my model is driven with a design table. This works for all kinds of different sizes of thread and lengths….
*Except* if I make the thread 4 inches or longer the entire model disappears.
If I preview the cut for the 4 inch model it shows up just fine. The underlying rod is there, the spiral looks correct, and when you click OK there are no rebuild errors… but the entire model just disappears. Make the thread 3.75 inches and it cuts fine.
I turned down the graphics settings and it made no difference.
I also checked the model on a second computer and it seems to have the same problem.
Has anyone had similar problems? Any ideas what could cause/fix this? I can provide the file if someone wants to take a look at it.
————————
Update here is the file…
crashing_file
Chris Serran, and 
behnt are discussing. 
CBL 8:29 am on January 16, 2009 Permalink
I haven’t experienced that problem, but then I’ve never created helical threads that long.
Can you post the part here for testing?
Matt 8:45 am on January 16, 2009 Permalink
How do I post the part?
MarkKaiser 9:01 am on January 16, 2009 Permalink
To post a part, I believe you go into the dashboard, upload it, then link it in the post with the url (of the dashboard location).
admin 9:31 am on January 16, 2009 Permalink
Send the file to me and I will attach it. That functionality will be here soon.
You can also click “Edit Post” and in the edit window there is a icon at the top right that will allow uploads of files.
Ben
guido 9:39 am on January 16, 2009 Permalink
Matt,
You may be having a memory problem, or lack of it, I suppose I should say.
I had similar problems in that although short threads slowed my machine down, eventually it would solve, and the longer threads took much longer, and after a size limit, which I cannot re-call right now, after the seemingly ok preview, the model simply did not show up . When I increased my RAM from 1 to 2 GB, the problem decreased proportionally.
For what it is worth,
Guido
Matt 10:31 am on January 16, 2009 Permalink
Uploading does not appear to be working. I either get a ‘does not meet security requirements’ or it just disappears.
I don’t know how to send things to you ben.
admin 11:50 am on January 16, 2009 Permalink
Update the file has been added to the post in the original text and here
crashing_file
Matt 12:01 pm on January 16, 2009 Permalink
Thanks Ben.
I still have no idea what is going on with this file.
admin 12:23 pm on January 16, 2009 Permalink
I will experement with this and see what is going on. But in the mean time a much lighter weight than a helix (system resources wise) to make a thread is in a video I made a while back. It is near the end of the video of “Springs Drawings and Weldments” substitute the sweep boss with a sweep cut.
Springs Drawings and Weldments
admin 12:54 pm on January 16, 2009 Permalink
Ok I believe this is a bug of sorts with the helix. It may be worth looking into the SR’s at SolidWolks to see if you need to submit this to them. Anyhow I have a different way of doing this using my method of cut-sweep that is much lighter weight and like I said before much easier on the system resources. Problem then lies with adding a variable pitch at the end cut near the head. I end up with a non-tangent edge I cant clean up but if you are rendering these you may get away with it
4″ threads that work
Chris Serran 12:55 pm on January 16, 2009 Permalink
I don’t have an answer as to why it’s happening, but when changing the Height Parameter on helix 3 from 4.05″ to 4.03″ it works. However, this may give you undesirable results as the helix may be slightly different than everything else.
Changing the heigt to 4.06″ or 4.04″ gave a rebuild error of “Operation failed due to geometric conditions”.
MarkKaiser 12:57 pm on January 16, 2009 Permalink
Matt,
I can’t get the 4″ long thread to work on my computer either. If you’re on subscription, I’d send it to your VAR and see what they think. It probably won’t get you results, but if it’s a software bug, they need to know.
I initially thought it might have something to do with how the thread cuts into the ‘inverted’ chamfer, but I removed the chamfer, and it still would perform the thread feature.
Matt 1:18 pm on January 16, 2009 Permalink
Thanks for the assistance everyone. I think this is going to the VAR.
Unfortunately I can’t use the alternate cut-sweep method both because of the lift out and because when I tested it it would not drive though the design table correctly (another bug?). It kept converting rotations to degrees and refusing any number of degrees above 360 from the table.
Chris, I am not sure what height you are referring to. Did you change D30002@helix/spiral1 in the design table or is this something else?
Chris Serran 1:29 pm on January 16, 2009 Permalink
I edited Helix/Spiral1, in there is a table and I changed the value in the 3rd row.
I didn’t examine the design table to see what value in there controlled it.
I think it may be a graphics bug. When you click in the area of the “disappeared” body the shortcut bar pops up.
Matt 11:14 am on January 22, 2009 Permalink
FYI.
I sent this over to the VAR (who has been less than helpful) and did some more testing on my own.
It appears that the problem is somehow related to the chamfers as it goes away when all three are removed or the center ones are made significantly smaller.
I think this is a software bug as there is no reason I can think of why you shouldn’t be able to cut through a chamfered extrusion with a swept cut.