plunge mill "newbie"

[GeoGirl]

Hi gang, I try not to post here much because I am so green. I want to plunge mill a ring 1 inch deep and I have the right tools. I did a search here, but kinda need more help. Do I have to create a surface first? The only plunge operation I can find is under surface plunge rough. Is there other ways? When I try to use a surface it asks for a grid and I'm not sure what that is. Sorry to be such a pain, but the help files are no help.

:-(

TIA

GeoGirl

[?Mark]

Lesson on plunging by Roger Peterson

hth

[john316]

.

 

You're no bother, we're here to help when we can.

 

Some of the major insert cutter manufacturers have pretty good plunge mills.

 

I haven't done any of it in a while, but the last time I used it, it only cut in square or rectangular pockets. Maybe they have expanded the options since then.

 

If I remember right, you'll need a surface on the floor and containment boundary.

 

HTH

 

.

[Dan_AKA_ROY]

Thanks Mark (and Roger Peterson). I never used rough plunge ever, but I did learn quite a bit from that thread!

 

GeoGirl, there are specialty plunge endmills to use for plunge roughing operations. You can use drill bits, also, but don't listen to me. I don't plunge ever, so unless someone in here confirms drill bits are a decent choice - go with plunge bits.

[?Mark]

Geogirl, there is plenty of threads about this topic to get you started. Beware though, plunge milling is somewhat intimidating at first. There is a lot of chips flying around at VERY high velocity hitting the machine enclosure with quite a bit of force... But you'll get used to it...

[GeoGirl]

Thanks gang,

I have enough to play with now, not sure if I grasp it all, but will give it a try.

 

Thanks again

GeoGirl

[john316]

.

 

The real learning happens when it's on the machine. Have no fear.

 

.

[Colin Gilchrist]

GeoGirl,

 

If you are using X2 there are some significant problems with the retract heights and feed planes. I've had to do a bunch of work arounds to get it to work at all. Most of the time I just construct wireframe of the toolpath, then use the point toolpath and create it manually. That way I can also retract away from the wall .02 on the retract. Plunge mill tools have a tendency to deform and be pushed away from the cut slightly. When the tool retracts, there is still pressure on the tool and the inserts can take a beating. If you rapid retract, I've even seen them get ripped right out of the insert pocket. Just be careful. Someone needs to write a good plunge rough utility for mastercam.

 

HTH,

[GeoGirl]

Hi, with all your help I think I will be ready to try this in the morning. Any suggestions on feed and speed? I have an Ingersoll 15s (2 flute 1.375 dia, one insert on the outer edge, the other in the center to drill a blind hole) The center hole is there and I have about .800 along the edges of this pocket (kinda of an oval shaped pocket) to remove. Material is 4140 HTSR. If I am reading the charts right...the RPM should be 1450 - 2320, fr 7 - 18. (I used the formula based on 1 insert, should i be basing it on 2?)

TIA

GeoGirl

[GeoGirl]

Oh, and what should my step over be? I was thinking .125, but I'm just guessing :-)

[Guest]

I would suggest keeping the step over slightly more than half the diameter of the cutter being used. This way you can keep the center cutting feature of the tool always engaged.

 

So maybe 65% of the dia.

[GeoGirl]

I did not get it to work :-(

[crazy^millman]

What did you try specifically that did not work, Step over, Speed, feed that you tried? I have done as much a 2.6 width with a .3 step over on are plunge mills in the same material and had great results.

[GeoGirl]

maybe its because I could only plunge the first insert. My cutter must have been too big. I had a 1.5 dia and the wall I had to machine away was .300, so I tried a .125 step over. I have never seen anyone plunge mill, but it sure was sure loud (maybe thats normal) Maybe I was to chicken to feed harder. I have a huge job that will require plunge milling in the next month, our tool supplier suggested the tool and it is using the same material. I will post another question when I can apply it to this particular job. I will go back and see what I was trying to use as a feed and rpm. I then tried to use a rougher with no luck. Never tried a rougher in steel, but it was bad.