How to do a undercut program

[TERRYH]

I am working on a punch for a trim die, it has undercut surfaces below the trim edge, is there a program I can do this with using a lolipop style cutter? i had done it years ago before they had these high speed toolpaths but for the life of me cannot remember which one it was or if they moved it.

[Colin Gilchrist]

Flowline and Surface Finish Contour both support undercutting. Can you share a file?

[TERRYH]

yes I can share 

 

[TERRYH]

Using the SFC it did not follow the surfaces and actually do the undercut it just cut straight down. and the detect undercuts is greyed out.

[gcode]

Maybe high speed water line with the tilt tool collision checking option enabled enabled???

This could be done with a Module Works Unified toolpath as well 

[TERRYH]

19 minutes ago, gcode said:

Maybe high speed water line with the tilt tool collision checking option enabled enabled???

This could be done with a Module Works Unified toolpath as well 

It's being done on a 3-axis machine not sure that would work.

[Chally72]

15 minutes ago, TERRYH said:

It's being done on a 3-axis machine not sure that would work.

Unified toolpaths can be locked to 3 axis on the Tool Axis Control page and posted out and run on 3 axis machines

[TERRYH]

I can't get anything to work correctly they want to cut straight down ignoring the undercut .

[bird2010]

1 hour ago, TERRYH said:

Using the SFC it did not follow the surfaces and actually do the undercut it just cut straight down. and the detect undercuts is greyed out.

When using Surface Finish Contour, the tool must be able to undercut for the undercut option to be enabled. You may not have selected the tool correctly....

Using Unified should be a better way...

[bird2010]

2 hours ago, gcode said:

Maybe high speed water line with the tilt tool collision checking option enabled enabled???

This could be done with a Module Works Unified toolpath as well 

All high-speed toolpaths do not support undercutting, although the tool axis can be tilted
It is too common for multi-axis to encounter undercutting, but if the undercutting area cannot be calculated, tilting the tool axis is useless.
High-speed toolpaths do not support undercutting, which is a pity.....

 

[gcode]

11 minutes ago, bird2010 said:

All high-speed toolpaths do not support undercutting

Doesn't matter.. you can fake it

Program it with a high speed waterline with a vertical spindle 

Add a live solid to the top of the part use as avoidance geometry  

go to the holder page

select "tilt to avoid gouge " and choose your avoidance geometry 

adjust the size of the solid until you're happy with the resulting tilt

and you're good to go.

This is no help to TerryH though as he's restricted to a 3X machine.

 

 

[bird2010]

13 minutes ago, gcode said:

Doesn't matter.. you can fake it

Program it with a high speed waterline with a vertical spindle 

Add a live solid to the top of the part use as avoidance geometry  

go to the holder page

select "tilt to avoid gouge " and choose your avoidance geometry 

adjust the size of the solid until you're happy with the resulting tilt

and you're good to go.

This is no help to TerryH though as he's restricted to a 3X machine.

 

 

It will tilt...but it won't go into undercut range!...

[gcode]

42 minutes ago, bird2010 said:

It will tilt...but it won't go into undercut range!...

you can big foot it and force it to do what you want 

there will be nothing automatic about it.

[bird2010]

26 minutes ago, gcode said:

you can big foot it and force it to do what you want 

there will be nothing automatic about it.

It will tilt...but it won't go into undercut range!
Because the undercut range cannot be calculated...the calculation core does not support calculating undercuts (HSM supports)
My English is not good, I think it is better for Colin Chally72 Aaron to explain...
Having a tilt function does not mean that you can enter the undercutting range!....Tilting and undercutting are different

[#Rekd™]

Could you modify a duplicate solid (remove the upper portion that is overhanging the undercut area (make the model shorter by that amount)). Then surface it with a lollipop mill? 

[gcode]

50 minutes ago, bird2010 said:

It will tilt...but it won't go into undercut range!
Because the undercut range cannot be calculated...the calculation core does not support calculating undercuts (HSM supports)
My English is not good, I think it is better for Colin Chally72 Aaron to explain...
Having a tilt function does not mean that you can enter the undercutting range!....Tilting and undercutting are different

Terry is trying to cut straight walls that are in the shadow of overhanging geometry.

You ignore the overhanging geometry and develop a toolpath that cuts the desired straight walls only

Then you create avoidance geometry to make the tool tilt and avoid the overhang

It is not easy and it's a lot of work but it can be done.

You would only go to all this trouble if you did not have a multiaxis license.

This doesn't help Terry a bit because he has to build this part on a 3 axis machine.

[Jake L]

7 hours ago, TERRYH said:

yes I can share 

 

Did a file get posted somewhere? Am I blind? I'd like to give this a shot as well

[Matthew Hajicek - Singularity]

I just did an undercut fillet with a T-slot cutter the other day.  I used Flowline, with Direction and Depth Limits, and it worked perfectly.

[crazy^millman]

25 minutes ago, Matthew Hajicek - Singularity said:

I just did an undercut fillet with a T-slot cutter the other day.  I used Flowline, with Direction and Depth Limits, and it worked perfectly.

That is just crazy I tell you. Crazy talk.

[bird2010]

12 hours ago, gcode said:

Terry is trying to cut straight walls that are in the shadow of overhanging geometry.

You ignore the overhanging geometry and develop a toolpath that cuts the desired straight walls only

Then you create avoidance geometry to make the tool tilt and avoid the overhang

It is not easy and it's a lot of work but it can be done.

You would only go to all this trouble if you did not have a multiaxis license.

This doesn't help Terry a bit because he has to build this part on a 3 axis machine.

I should understand what you mean...select the geometry and let the software determine that there is no undercut. This is also a way! But it must be suitable for the graphics. If avoidance geometry is used, it may still cause undercut.

If there is no multi-axis permission, as Colin said, Flowline and Surface Finish Contour directly support the calculation of undercut, and using avoidance geometry should not affect it.
  cut straight walls that are in the shadow of overhanging geometry....Surface Finish Contour is more suitable
Surface Finish Contour needs to use a tool that can undercut to enable the undercut option. TERRYH did not use the correct tool, so the undercut option is grayed out.

[bird2010]

16 hours ago, Chally72 said:

Unified toolpaths can be locked to 3 axis on the Tool Axis Control page and posted out and run on 3 axis machines

Is it possible to use Unified toolpaths independently for 3 axes in the future?
Because not all users will use multi-axis licensing...

[crazy^millman]

11 hours ago, bird2010 said:

Is it possible to use Unified toolpaths independently for 3 axes in the future?
Because not all users will use multi-axis licensing...

It been requested numerous times over the years. Join the Mastercam.com forum and send an email to QC and add your name to the list.

[TERRYH]

Playing with this if I use a 1/2" carbide burr (lollipop cutter) it works just fine like I thought it should, however it will not work with a button cutter. with the burr selected the detect undercuts is active but it grayed out on the button cutter. I just didn't want to use a burr because of the length am afraid it'll will just beat the xxxx out of it and look like crap. Thanks for all the suggestions.

[Colin Gilchrist]

17 minutes ago, TERRYH said:

Playing with this if I use a 1/2" carbide burr (lollipop cutter) it works just fine like I thought it should, however it will not work with a button cutter. with the burr selected the detect undercuts is active but it grayed out on the button cutter. I just didn't want to use a burr because of the length am afraid it'll will just beat the xxxx out of it and look like crap. Thanks for all the suggestions.

Terry,

Can you share a file? You mentioned "yes" earlier, but no file attached to the thread...

Thanks,

Colin

[gcode]

40 minutes ago, TERRYH said:

burr selected the detect undercuts is active but it grayed out on the button cutter

Have you tried defining your button cutter has a dove mill?

That may not support undercuts  either 

I use button cutters all the time for 3D roughing and profiles and it can be a real PIA

One on my requests on the new My Voice section of Mastercam.com was for a formal button cutter

in the tool library. It hasn't gotten many votes though.