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When to plunge rough?

Dicks4fingers

Aluminum
Joined
Dec 24, 2019
I'm trying to put 2 to 1 and even some .75 inch wide pockets into 304 stainless from about 1 inch to three inches deep. It's a bit of a pain and as someone who tries to throw hem style paths at everything I don't like it. Anyone got any better ideas? I got to do a bunch of these
 
Are your pockets enclosed on all sides or do you have some open air to get in with a tool?
Also, are they .75" wide or are you saying they are a range from .75-2" wide?

I would do it either with a feedmill or a plunger but it depends on the pocket size and type. :D
 
the pockets are about 1.5 wide but have a lot of stuff in them so some parts are only about .7 or .6 wide
 
I don't know if high feed mills will help. My biggest problem is clearing chips and I can't use through spindle coolant
 
Well plunge milling isn't going to help with chip clearance either unless you us something spiral fluted. Most plunge mills are just shell mills with a little different geometry. Can you describe what you mean by your pockets having stuff in them?
 
High feed endmills just do not like pockets unless you do a ever decreasing x-y as the z move down.
I'd drill a starter hole, step and plunge mill. Then go clean it up.
In a enclosed pocket one has to be careful of leaving slugs or big slivers on plunge mill op. You don't want to hit one of these.
Lots of parts and a few parts different when thinking about this.

It is tool often used on manual machines. Harder to program on a cnc,
And when you do plunge rough it does not plunge straight. People with life doing it on manual sort of a given deal.
CNC programmers get so surprised.
Bob
 
First of all, since you don't have high-pressure coolant, go get your rosaries. :rolleyes5:
Use a 1" insert drill and drill a hole in the center of the pocket and then plunge the rest out with the drill.
Then use a 1/2" EM with HEM to finish the walls and corners.
 
Out of all of OPs examples, the only one I would even consider plunge milling would be a combination of his two extremes. Something like a .6 width by 3" deep. And even then... meh? You can probably pick that out without too much trouble. He also said that his pockets have a bunch of "stuff" in them so maybe there are only a few little areas where it even gets that narrow and most of it is wide open?

Mr Dickfingers can you show us your pockets so we can know what you're dealing with?
 
Depends on how many you have to do but I could see pre-drilling with a 3/16-1/4" drill and follow it up with a bigger drill to get most of the material out of there.

I like Guhring drills due to some trouble they got me out of years ago drilling hundreds of 0.017" holes about x10 deep in 304 but any of the reputable drill manufacturers would work. I prefer cobalt drills in stainless as they seem to be a tad more predictable in the stainless I've ran and when the drill breaks you can machine it out easier than carbide.
 








 
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