Check Flowline Motion for Gouge

[psco21]

Hello!

 

I am trying to make a rough cut pass using Surface Rough Flowline. The part is a convex cylinder. However when I have Check Flowline Motion for Gouge checked in Cut Control, the toolpath only shows for the top half of the part stopping at the midpoint. I'm thinking that it doesn't like the undercut but when I uncheck the Check Flowline Motion for Gouge box, it does a completely different toolpath which leaves a flat surface instead of the desired convex cylindrical surface.

 

Thanks!

[Guest]

Mastercam question,.  moving to the Industrial Forum

[billb]

Yes, rough/flowline does not support undercutting.  It finds the "finish" flow cut and then creates roughing passes from the top down to the "finish" flow cut.  This doesn't work when there are undercut areas (you want the "rough" steps to start below and step up).

 

When you enable "check flowline cut for gouge" then the "finish" flow cut has the undercut portions trimmed away.  The rough cuts allow you to rough out the top (convex) portion of the part.  If you uncheck "check flowline..." then the undercut portions are kept and the resulting rough cuts machine the entire part away.

 

For some time, I've considered adding a warning about undercutting not being supported in rough/flowline.  I was going to tie the warning message to the undercut tool (slot, lollipop, dove mill).  But, as you point out here, the message should come out even with a convex cutter shape (bull, ball, flat) when "check flowline..." is unchecked.

 

You might get what you are looking for if you use rough/pocket and an undercut tool shape (particularly if you give it an explicit entry point).

[psco21]

Thank you for your reply.
 
I'm using a wheel with a radius and was hoping that the top part of the radius wheel edge would cut the undercut.
 
Rough/Pocket seems to go all around the part because there are no check surfaces allowed. I've attached a screenshot.
 
Thank you.

[billb]

Thanks for the picture of your part.  You are right - no check geometry in rough/pocket.  You'll likely need to extend the part along its length (both directions) to keep the tool from rolling around and cutting the sides.

You can turn off the roughing passes and turn on finish passes (with multiple finish passes) to rough out the shape but avoid all the air cutting.

 

Finish/contour would work nicely for you (it allows check geometry!) but you only get one finish pass.  I suppose you could create several (3, 4?) finish/contour operations each with successively less stock to leave.to rough out the shape.

 

(Surface/rgh/restmill doesn't support undercut cutters.)