Toolpaths that allow undercuting

[Machineguy]

Morning,

I don't do much work that required undercutting tools. I need some help in knowing what surface toolpaths allow undercutting.

I'm doing a groove on a drum for cable winding (Like a crane would use).

Its a helix path. using a 1/8 rad woodruff cutter. groove in the drum is .113 deep but is a .139 rad.

lead is .286 on a 8.576 dia OD.

Must be done from the end being the top. 4th is not a option due to a long reach if done from the side.

Need a lead in and a lead out to clear the part.

 

I'll work it out, just need a direction on what might work.

 

Thanks

Machineguy

[?Mark]

Morning,

I don't do much work that required undercutting tools. I need some help in knowing what surface toolpaths allow undercutting.

I'm doing a groove on a drum for cable winding (Like a crane would use).

Its a helix path. using a 1/8 rad woodruff cutter. groove in the drum is .113 deep but is a .139 rad.

lead is .286 on a 8.576 dia OD.

Must be done from the end being the top. 4th is not a option due to a long reach if done from the side.

Need a lead in and a lead out to clear the part.

 

I'll work it out, just need a direction on what might work.

 

Thanks

Machineguy

Finish contour and flowline. Also 5 axis toolpaths will do that (even with 4 axis output).

Finish contour is likely your best bet here. Post the file here or pm me if you have problems and I'll have a look.

[mkd]

don't forget about turning off the gouge checking; that is the only way they will work.

 

use "direction" for lead in / out

[Machineguy]

Mastercam keeps crashing. Tried both flowline and contour surface finsh paths. the tool will fit the main groove, but the lower one that is the attachment point groove for the cable no bueno.

Toolpaths are not working, yet.

So I'm stumped at the moment. I may need a smallet cutter, like one with a .187 Rad.

 

Take a look, see what is happening. I took the bad paths out. It was crashing MC

 

Machineguy

5000A30056_01.MCX-7

[?Mark]

Ok...you want to go around several times in a sort of "threading" movement?

[Machineguy]

Mark,

That would work since the cutter is smaller then the groove.

The lower section may require a smaller cutter since the angle is bigger.

[Machineguy]

Are you thinking a threadmill path ?

[?Mark]

With no 4-th axis the flowline is a way to go here. I think the problem you had is that you need to segment this type of toolpath into "simpler" sections. Flowline can be "finicky" when it comes to that if you select too many surfaces...

See if that's what you are after...

 

what's your email? that file is too big for this forum...

[Machineguy]

PM sent

[?Mark]

Here is a screen shot

[?Mark]

Back at you.

Now you just need to finish the lower section with a new toolpath...

hth

[mkd]

beat me to it....mice inside my xeon-dog computer still running....

[?Mark]

Or something like that if you have a tool that is "close enough" or wide open tolerances...

 

Pardon the lead in/out...just change the sweep angle to 90 deg...

5000A30056_01-02.MCX-7

[mkd]

.

[Machineguy]

Thanks Mark

 

Looking at the file, I'm trying to see what I did wrong.

Looks like 1 drive surface, instead of 3. No check surfaces. Ok.

Also looking at the lead in. I Missed that !

 

Something learned everyday.

 

Machineguy

[?Mark]

Thanks Mark

 

Looking at the file, I'm trying to see what I did wrong.

Looks like 1 drive surface, instead of 3. No check surfaces. Ok.

Also looking at the lead in. I Missed that !

 

Something learned everyday.

 

Machineguy

In 3d contour the biggest thing was turning off the "infinite look ahead"...hth

[Machineguy]

My dealer just called. Said the same thing as you did Mark!

 

What a crew we have here!!

 

Machineguy

[Machineguy]

Actually the 180 deg works fine. It ramped off the left side and cleared the part.

I finished the rest of the groove with a smaller cutter. Looks good.

Changed the step over to .010". Now its 3 hrs run time. a little more tweeking needed.

As always I pgm the fixture last.

A pocket in the fixture is a must so the cutter has room.

 

Thanks again.

 

Machineguy

[jeff]

What about doing it on a lathe? I used to have a macro program for Fanuc for rope drum threading. I'll have to see if I can find it.

[Machineguy]

Jeff,

 

Did you look at the part? Not a lathe part in its current form.

I only have a SL-10.

 

And its offical, No new machines this year.

 

Machineguy