Plunge Milling in Mastercam

[mkd]

On 9/25/2017 at 0:16 PM, Matthew Hajicek™ - Conventus said:

Will it pull the cutter away from the work at the bottom of the stroke before retracting?

slightly being a smartaxx, but would you need do that on a lathe?. then it shouldn't be needed on a mill.

On 9/25/2017 at 0:27 PM, C^Millman said:

I would create my line and then my pull away. I would then do a 3D Contour using that and away I went. More work, but I can always put the tool where I need it and always pull it off like I want every time. Other ways to do it, but I got out of Plunge Milling sometime ago.

agreed. It wouldn't possibly work (better than dynamic) with MC's plunge/surfacing toolpaths, which is why I originally asked the question on other software that can control the locations.

[crazy^millman]

Was thinking about this thread and one thing you may not be considering and that is how much stress will go into the part with plunge drilling it? Something I have seen with this process in Ti is heat effect zones if not using 1000 psi and TSC (Through Spindle Coolant) A Coolant Chiller would also be a huge help here. Please do make your fixtures out of aluminum. People don't realize the effects of poor support for their parts over time. A broken clock is right 2 times a day and see it to many times people making fixtures out of aluminum because it is easier to machine. My experience with Ti is you want all the advantages you can get and using a strong stable and harmonic dampening material for your fixture is key. Running a one off that is a different conversation, but even would consider HRS, 4140 or 15-5 if the part warrants it. I don't think you need to step up to Invar, but have seen some very nice fixtures made out of it also.

[mkd]

I was just thinking of buying some aluminum for second op. Hahaha. I better go HRS.

[crazy^millman]

39 minutes ago, mkd said:

I was just thinking of buying some aluminum for second op. Hahaha. I better go HRS.

Well price wise I think the material is about the same. Machining wise yes HRS is more work, but over the long run you will be surprised how much it helps. I have fixtures I designed over 20 years ago still running in different shops made out of HRS or 4140. Not sure how many shops can say that about aluminum fixtures running Ti. I saw what running 20 parts through one aluminum fixture did in the last month. It looked bead blasted.

[Newbeeee™]

Ron - why fixtures out of invar?

Low expansion?

[mkd]

only ever done composite bond jigs out of invar. Never for a cnc fixture.

[Newbeeee™]

7 hours ago, mkd said:

only ever done composite bond jigs out of invar. Never for a cnc fixture.

Again - low expansion reasons?

Or project was under budget and money needed burning???

[mkd]

9 hours ago, newbeeee said:

Again - low expansion reasons?

Or project was under budget and money needed burning???

Low expansion while in the autoclave.

quite the sobering scene; coming from a shop where a .25" endmill was average to HBM plowing through invar skins with a Ø2.0" ball insert mll making a hellacious noise.

[crazy^millman]

23 hours ago, newbeeee said:

Ron - why fixtures out of invar?

Low expansion?

Stability and dampening that was needed for the part with crazy tight tolerances. 

[Leon82]

We used a sandvic 880 insert drill in a super invar job because the rep said it would work for plunging.

It did, but it sounded like crap

[mkd]

4 hours ago, Leon82 said:

We used a sandvic 880 insert drill in a super invar job because the rep said it would work for plunging.

It did, but it sounded like crap

interesting

[Leon82]

52 minutes ago, mkd said:

interesting

I went from 25 to 75% stepover.

Only about .300 deep at time. Then cleared the scallops with an insert mill 2 passes.

I used the transform in z for the 2 drills and insert mill. It worked well but I wouldn't use anything under 3/4 inch diameter for that application