Plunge roughing advice needed

[Metal Flake (clocked in)]

Looks like I'm going to be doing some plunge roughing in Titanium (cool right?). Never done plunge roughing though and I would really appreciate some noledgable advice.

 

I'll be using a insert drill for a starter hole and then a 5 flute insertable plunge rougher (both from Kennemetal).

 

Any help is much appreciated!!!

 

MF

[Fig sign]

Do you going to do surfaces or 2d(constant Z )plunge ?!?

 

I know one nice trick for 2d

[Metal Flake (clocked in)]

..constant Z (for now).

[rich]

What diameter of plunge rougher are you using?

What size of machine are you using this cutter on?The problem I found with kennametals plunge rougher is that it has little to no rake angle on the bottom of the cutter so when you plunge to a floor the whole width of the insert hits the floor and chips the inserts also that cutter has no chip clearance pocket in the bottom of it so chip evacuation is a concern if you are not roughing thru the part.

[Metal Flake (clocked in)]

Thanks Rich. I'll be using a 2.5D 5flute plunge rough and we're doing the test on a beefy Okuma vertical 50taper. We'll also be having the Kennemetal sales guy on site for the test :-)

 

 

Question to all: When the cutter rapids out, won't the decreased cutter pressure cause the inserts to drag the walls?

[rich]

KC9045 and 725 are good grades to start with. They are suppose to be coming out with an enhansed 725 grade soon. I don't know how deep you are going but I have found that if you go over 3 X D then you might want to consider removing a couple of inserts to reduce cutter grabbing. Yes, to your ? . the cutter will drag when you retract in z and the longer your tool the worse it is. that is why I prefer the carboly cutter over the kennametal. It uses a four sided insert that gives you two more cutting edges and the cutting edge is at 10 or 15 deg so the insert is tipped away from the side wall on the retract.

[TheePres]

Metal Flake,

I have been asked to look at Plunge milling some titanium parts, could you give us a status on how your project worked out?

[?Mark]

quote:

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that is why I prefer the carboly cutter over the kennametal

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We started plunging some years ago with carboloy 2" plunger and it's a real hammer. The only problem is that it touches against a material on retract which can destroy one edge of the insert.

Currently using iscar also 2" which is a lot more free cutting.

I found that all plungers like full engagement. That makes them stable and quiet. I use it a lot also on rough conturing when i have to remove lots of material. Works great. Run it dry with air. It's fascinating to watch it run. Seems like everybody wants to take a peek. When chips fly it sounds as if somebody is throwing rocks. Wish mastercam could make it a little easier to utilize this tool with plunger specific toolpaths...

 

Regards, Mark

[joe m]

I have used the Ingesoll 2" plunge cutter with good resolts in p20. All the plunge cutters seem to take a lot of HP.

[Nominal]

Question for all:

 

Has anybody did any analysis on how much time is saved/wasted by plunge milling?

 

What happens when one insert breaks on the way down into some inco at 20 ipm?

 

In the past I've experimented with plunging only to find I could do it as fast contouring with a hogmill. I'm sure the people that sell these tools think they're great, after all, what's the profit margin on a hogmill.

[?Mark]

quote:

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What happens when one insert breaks on the way down into some inco at 20 ipm?

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It'll take some refinement when it comes to speeds and feeds. I found plungers to be very predictable (unlike roughers in 17-4 ph and 4130) and make notes in job setup to change inserts after certain amount of parts.

I almost never leave this op unatended (hover my thumb over sp button and keep an aye on spindle load). Some peaple hate them because of this.

 

Plunging is also a lot easier on a machine than hog mills...

On some parts i can plunge in about 10' instead of 60'+ for hog miling so it's a substantial time savings but inserts are not cheap .

 

Regards, Mark

[herbert west]

We were plunging with a 2.0 iscar into hardened P20 down to about 6.0 deep on a Haas VF6 40 taper. What a racket! The spindle needed grinding after that and the vibration shook a bunch of wiring loose causing lots of alarms. Spindle coolant is a must as well full diametrical engagement. Operator carelessness turned the job into a mess and the machine was never the same again.

[5 AX]

I plunge titanium frequently with great success. Insert failure in the hog mill is inevitable. I only use them after plunging material away. Carboloy tool is the way to go. Thru spindle coolant with lots of feed on a very rigid machine. If vibration is a problem you will not have much success. The carboloy grade is F40. But if it is not a very rigid machine it is not worth your time.