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Breaking 1/2" Kennametal HARVI I TE ENDMILL while plunging

Ox

Diamond
Joined
Aug 27, 2002
Location
West Unity, Ohio
Cool, thanks, I will contact them! That left hand holder is close to what I need. My centerline is 120mm and I need to test what the min centerline dimension I can get to on the turret. I think it is just over 100mm but need to verify.

-Tom


Make sure that you are comparing apples.

That 69 and 96 would show up as dbl that on your offset register.
(I think anyhow - without an actual drawing that's not 100%, but purty sure)

The VDI30 ones that we made here have 5.5" and 9" C/L's, and have 1" holes in them.
But we can't use those on the Y axis main turret as they won't clear, and they won't clear the sub-spindle either on turret2, so we have to make sure to have the cut-off in position when we pick off.

Up to 4 tools per holder.


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Think Snow Eh!
Ox
 

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tome9999

Aluminum
Joined
Dec 7, 2018
I think the 69/96 are not double, they are the measurement from face of turret. Anyway, the Emco double (main and sub facing, not two on one side) boring bar holder I currently have pushes the limit of length (at 145mm) for a holder on the machine. Y has to be at 0 to index the turret. See:

3EC029B0-F200-4DB4-9CC3-AC3E9D2F3E18.jpg
F8732305-23CE-4EDD-BEB3-EDA75B5ADA4D.jpg
 

tome9999

Aluminum
Joined
Dec 7, 2018
I thought that you mentioned 30 somewhere....

PM91.3020L • Global CNC Industries

PM91.3020R • Global CNC Industries


If you are only looking for one or maybe two, then buying one is likely cost effective.
We made several like these in-house many yrs ago.



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Think Snow Eh!
Ox

Turns out I can't use a double holder like these. The turret only goes a couple mm below center of the spindle. The turret housing travel is limited by the sub-spindle on this machine. I do have a Y axis, so I could get/make a holder that has the holes +-Y on the holder. However, Y only moves about 3in total so this will limit the diameters I can use without interference. Looks like I need to re-think the tools I keep in the turret and/or get more efficient at swapping tools in/out.

This shows my 120mm long boring bar holder as low as it will go and it is barely below centerline. The 100mm short boring bar holder that is in the position above it in the picture can't get to centerline. It is only good if not going to center on bigger holes.

IMG_2042.jpg
-Tom
 

Ox

Diamond
Joined
Aug 27, 2002
Location
West Unity, Ohio
2" between C/L of your tools is usually good enough for C/L tools.

Just be aware of what is 3 doors down when you run Y- as you can (I can at least) run your tools into the way covers.
Hopefully your machine is better equipped.


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Think Snow Eh!
Ox
 

tome9999

Aluminum
Joined
Dec 7, 2018
2" between C/L of your tools is usually good enough for C/L tools.

Just be aware of what is 3 doors down when you run Y- as you can (I can at least) run your tools into the way covers.
Hopefully your machine is better equipped.


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Think Snow Eh!
Ox

I don’t think that is possible on this machine as long as I return Y=0 before rotating the turret(tool change).
-Tom
 

huskermcdoogle

Stainless
Joined
Nov 11, 2005
Location
South Texas
So this thread quickly went to bashing tool vendors as not knowing what they are doing.... There can be some truth to that statement. But that usually depends on who in that organization you are working with.

Even for a 1/2" Harvi 1 TE, .002 IPT is on the high end for slotting, no less plunging. Not saying it can't be done, but generally speaking I recommend 40-60% of the slotting feed for straight plunging or aggressive ramping. Especially in a weak setup such as a live tool holder. I am guessing the endmill was overloaded chip load wise due to the live head not keeping up RPM wise. So you ended up with an even higher chip load which ended up being a viscous cycle generating more chip load until failure.

Cut the feedrate until it works, it will be fine at the depth you are going to. I'd start around .0008"-.0012". Don't be afraid to use some short pecks, but don't retract more than the chip load. If you interpolate it/ramp it, unless you can get near 2xd in hole size, it won't make much difference other than now you will be putting side load on the tool as well, the biggest difference that it will make is if you have a shallow helix angle, essentially it is just reducing the effective z feed.

Best of luck.
 

tome9999

Aluminum
Joined
Dec 7, 2018
So this thread quickly went to bashing tool vendors as not knowing what they are doing.... There can be some truth to that statement. But that usually depends on who in that organization you are working with.

Even for a 1/2" Harvi 1 TE, .002 IPT is on the high end for slotting, no less plunging. Not saying it can't be done, but generally speaking I recommend 40-60% of the slotting feed for straight plunging or aggressive ramping. Especially in a weak setup such as a live tool holder. I am guessing the endmill was overloaded chip load wise due to the live head not keeping up RPM wise. So you ended up with an even higher chip load which ended up being a viscous cycle generating more chip load until failure.

Cut the feedrate until it works, it will be fine at the depth you are going to. I'd start around .0008"-.0012". Don't be afraid to use some short pecks, but don't retract more than the chip load. If you interpolate it/ramp it, unless you can get near 2xd in hole size, it won't make much difference other than now you will be putting side load on the tool as well, the biggest difference that it will make is if you have a shallow helix angle, essentially it is just reducing the effective z feed.

Best of luck.

So if I understand you, you are saying that a shallow helix angle isn’t that helpful because of the side load on the tool assuming I only make the hole slightly larger than the endmill diameter, right? And that just plunging with slower feed rate (and pecking) is better than that?
-Tom
 

tome9999

Aluminum
Joined
Dec 7, 2018
Cut the feedrate until it works, it will be fine at the depth you are going to. I'd start around .0008"-.0012". Don't be afraid to use some short pecks, but don't retract more than the chip load. If you interpolate it/ramp it, unless you can get near 2xd in hole size, it won't make much difference other than now you will be putting side load on the tool as well, the biggest difference that it will make is if you have a shallow helix angle, essentially it is just reducing the effective z feed.

Best of luck.

FOR WHAT IT'S WORTH, I got a new endmill (same one) and plunged at 1200 RPM, 0.002"/rev. I pecked at .125 increments down to 1" deep (same 4140 Q&T material). No problem at all, and the load meter only went slightly over 40%. I didn't use coolant, but it probably wouldn't hurt as it gets deeper to flush out the chips.

-Tom
 








 
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