Want to get opinon on this issue.

[Djstorm100]

Making Titan's T-1M. I'm using a destiny 3/8 rougher and 3/8 finisher. Roughing op is great for the walls, pocket. I switch to a pocking operation going full depth of 0.5". In the roughing op I leave 0.005 axial and radial.

Speed of both cutters are 4k, 0.0025 ipt, 30ipm.

In the pocket operation I have the endmill just plunge down at 10ipm and start hogging out material. Everything is fine, however when the tool does OD of the pocket walls, it's also doing the floor. I'm think deflection is causing the center area of the pocket to be more proud than the OD of the pocket.

Am I crazy to think Tormach 1100 should be able to do this? Plunge down to floor, finish the floor and then when going to the OD of pocket doing the wall and floor at the same time? Hope this makes sense.

The red lines are the areas where the little "island" is more proud than the finishing tool path for the OD of the pocket.





Pocket Tool Path





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[jwatte]

Every mill will have some tool deflection, as the tool itself is bending.
Are you using HSS or carbide cutters? Carbide is going to deflect less. Also 4k seems slow for carbide for finishing.
What I would try: Use carbide for finishing, increase speed, reduce chip load.
Also, maybe leave less at the bottom than on the walls when roughing?
If that doesn't work, you could verify your assumptions by having a first finish pass do the bottom but still leaving stock on the walls, and then a second finish pass for walls only.

[Djstorm100]

Yes carbide.

Decrease chip load for finishing..NOT for roughing correct?


I'm thinking out loud but if I had tool deflection I would think by doing coutour of the walls but leaving the same amount of floor as I left on roughing, by then doing a 2d adaptive or pocket op the tool would then be surrounded by the same size stock all around. Does that make sense ?

Before the cutter is cutting a .25 of material off the floor but when it gets to the wall it's cutting the floor (.05 thickness) and the wall at (0.05 thickness and 0.5 high). It's not even load. What ti feels like is the tool's tip is getting sucked in to the part causing the bottom of the tool to angle. When the tool angles to one side the other side cuts in the floor farther.

Every mill will have some tool deflection, as the tool itself is bending.
Are you using HSS or carbide cutters? Carbide is going to deflect less. Also 4k seems slow for carbide for finishing.
What I would try: Use carbide for finishing, increase speed, reduce chip load.
Also, maybe leave less at the bottom than on the walls when roughing?
If that doesn't work, you could verify your assumptions by having a first finish pass do the bottom but still leaving stock on the walls, and then a second finish pass for walls only.

[AUSTINMACHINING]

If finish is critical do the floor first and leave .005 on the wall. Then do the wall but stay off the floor a few though so your not dragging the bottom of the tool while finishing the walls.

[Djstorm100]

If finish is critical do the floor first and leave .005 on the wall. Then do the wall but stay off the floor a few though so your not dragging the bottom of the tool while finishing the walls.

Wouldn't that little ledge be noticeable? I'm more using it as practice for when I start taking on jobs.

[jwatte]

Yes, lower chip load, higher speed, for finishing only.

I'd finish the bottom before the walls, because then if I mar the walls during finishing, the wall finish will fix that. But if the bottom is most important for you, the other order is good too! Finish the wall with a small amount of floor stock to leave, and then finish the bottom.

[Djstorm100]

Yes, lower chip load, higher speed, for finishing only.

I'd finish the bottom before the walls, because then if I mar the walls during finishing, the wall finish will fix that. But if the bottom is most important for you, the other order is good too! Finish the wall with a small amount of floor stock to leave, and then finish the bottom.

Higher speed = RPM or IPM?

The floor is important because it's what I'm having issues with lol. how would you finish the bottom with out cutting in the wall? Would have to leave atleast 0.002 radial. What'm nervous of by doing it that way is having mis match floor lever.

[AUSTINMACHINING]

Wouldn't that little ledge be noticeable? I'm more using it as practice for when I start taking on jobs.

Depends on your application

.002 ledge on the bottom corner would be hard to detect.
Here's an extreme example for molds, but basic principles apply.

https://m.youtube.com/watch?v=ZEM6ny2h1ZY

[Djstorm100]

Depends on your application

.002 ledge on the bottom corner would be hard to detect.
Here's an extreme example for molds, but basic principles apply.

Thanks! I totally forgot about this video. I figured it out. Although I turned the finishing speeds way down. It came out perfect


Solution: Roughed out but left .005 radial and axial. Then did a contour leaving 0.003 axially. This cleaned up the walls. Then the pocket routine cleared up the floor. For these two ops I ran it slow. Going to run another piece and crank it up.

[jwatte]

Higher speed = RPM or IPM?

RPM!

"Feed and speed" means "IPM and RPM"

[Djstorm100]

Well I figured it out. Roughing left 0.005 on the floor and the wall. finished the wall but left 0.002 on the floor. Did the pocket and it came out smooth as a glass. Ran the part again but with faster speeds and feeds (what I was originally running) and it came out just as smooth. I'll the reverse method in the books as well to try out sometime.

Thanks guys

[CL_MotoTech]

I was going to say, that's definitely CAM related. Been there myself.

[nitewatchman]

How thick is the bottom surface of the part?

[Djstorm100]

How thick is the bottom surface of the part?

Bottom of pocket to bottom of the part is 0.25

https://myhub.autodesk360.com/ue28fd...670363bffacc7f

- - - Updated - - -

I was going to say, that's definitely CAM related. Been there myself.

I agree, I think it's more of a tool deflection and machine rigidity. Use use the came to overcome short comings of the Tomrach.