Problem with slot on 4th axis

[jeff]

A simple L-shaped slot on my rotary. 

After looking closely, Mastercam isn't cutting the walls straight. Can someone look at my file and tell me what I'm doing wrong?

The endmill seems to be staying away from the bottom of the slot and only making contact at the top of the slot.

XXX.mcam

[Reko]

They are both straight slots, milled thru to each other... the walls are not perpendicular to the C/L of rotation... don't use axis substitution, use 3+1.

 

Just locate over top of each slot and mill them thru to each other.

[jeff]

Ahh yes, I see what you're saying.

Thanks!

[crazy^millman]

If you have 5 Axis then you could Swarf them and use 4 Axis output also. You will have to use the old school swarf, because of two major things missing in the new swarf. #1 the ability to force only 4 Axis output #2 the ability to pick a start surface.

 

Using the Solid Surfaces didn't do what I wanted so I old schooled it with chains and got what I would want to run on a machine. Here is a link to the file.

 

https://www.dropbox.com/s/o88yym8upkcinn1/5th%20Axis%20XXX.mcam?dl=0

 

HTH

[crazy^millman]

One thing I didn't mention on the chains was I converted the 3 entities for the top on one area into one spline because the bottom was 2 entities. It is where the bottom of the shape is a full radius and the top of the shape is 2 radius and one flat. In situations like this that is where Old School and sync by entity is a good approach. If you wanted to get real precise on the motion you could create points on each of the entities that would match top and bottom and the toolpaths would be really smooth motion also. Really a 5 Axis part not a 3 Axis part in one operation, but gets it close enough to call it good enough.

[Colin Gilchrist]

Try the Roll Die Chook. It is made for cutting with Axis Substitution, where the slot walls are offset from the centerline of the Rotary. The nice thing about Roll Die, is you don't need a Multi-Axis License. It works with 3X licenses.

[jeff]

Try the Roll Die Chook. It is made for cutting with Axis Substitution, where the slot walls are offset from the centerline of the Rotary. The nice thing about Roll Die, is you don't need a Multi-Axis License. It works with 3X licenses.

I tried that. Reko's advice has given me the best results so far.

[crazy^millman]

I tried that. Reko's advice has given me the best results so far.

 

Reko's process would cut the best part on a 4 Axis Machine. I was just giving you different ways to cut it in one shot.

[jeff]

Reko's process would cut the best part on a 4 Axis Machine. I was just giving you different ways to cut it in one shot.

I don't have multiaxis 

I wish I did though, but then again I'd probably be bald from pulling my hair out trying to learn it. 

[So not a Guru]

I don't have multiaxis 

I wish I did though, but then again I'd probably be bald from pulling my hair out trying to learn it. 

Been there!

[MrFish]

Reko's process would cut the best part on a 4 Axis Machine. I was just giving you different ways to cut it in one shot.

Hi Ron, Your tool path actually violates the inside corner of the slot. There would need to be extra geometry created to swarf the modelled slot due to the way the walls taper to a point above the lower rail at that inside corner. So yet again we wish all designers were machinists !!

[crazy^millman]

Hi Ron, Your tool path actually violates the inside corner of the slot. There would need to be extra geometry created to swarf the modelled slot due to the way the walls taper to a point above the lower rail at that inside corner. So yet again we wish all designers were machinists !!

 

Yes you are correct it does where a 5 Axis machine or breaking it up in 3+1 would be needed to make the best part possible. I was just throwing together a thought for others to review not that I would machine it that way sorry if anyone thinks that is the best approach on a 4 Axis from my example not meant in that regard.