1/2" Endmill plugging

[Marshal]

I'm having problems with our 1/2" endmills plugging when cutting aluminum. It only seems to happen on one particular place in the part, which is cut out of a 12x12x1/2" plate, and only happens when we cut the center 8"x6" halfway through. It's a full width slot, so that's certainly not helping matters any, but we do two other full width slots with that cutter on the same part that go completely through, and the cutters never seem to plug on those. This leads me to believe it's an issue with our fixture, which doesn't seem likely since the center block is held in with 4 screws and two dowels, with 4 more screws holding the outside pieces in. It also doesn't happen on every single plate, usually just when I'm not paying attention to the thing running. We've got plenty of coolant from two directions hitting the cutters, so I don't think it's getting hot, but it's certainly not always evacuating the chips. Spindle speed is 3500, feed rate is 45, so a feed per tooth of 0.003". We're also ramping in, so that should be helping right?

 

We're using 4-flute SGS tools with a Ticn coating.

 

Any ideas?

[rgollar]

For aluminum I prefer 3 flute osg blizzards. 4 flute is not enough chip evacuation. Plus your rpm is low for aluminum. My machines only go to 7500 rpm but I always cut at that speed and the chips just fly out with no problems. I have great success with streaker end mills from Imco. They last so long in aluminum with good coolant flow.

[Marshal]

For aluminum I prefer 3 flute osg blizzards. 4 flute is not enough chip evacuation. Plus your rpm is low for aluminum. My machines only go to 7500 rpm but I always cut at that speed and the chips just fly out with no problems. I have great success with streaker end mills from Imco. They last so long in aluminum with good coolant flow.

 

I'll have to double check the spindle speeds and see if I can convince our old machinist to run them faster. It doesn't happen on every part, but it's certainly annoying to know that it has the potential of happening and always when we're not around to stop it before it ruins the part.

[BenK]

I agree 3 flute is the way to go in aluminum. We use 3 flute end mills from Helical. I feed them at 14000rpm @ 210ipm.

[Rstewart]

I'll have to double check the spindle speeds and see if I can convince our old machinist to run them faster. It doesn't happen on every part, but it's certainly annoying to know that it has the potential of happening and always when we're not around to stop it before it ruins the part.

 

 

I would think the "old machinist" should know better than to try and slot Alum with a 4 flute E.M. Switch to a 3 or 2 flute and get those RPM's ^^^^^

[Mr. M]

Even a cheap uncoated 2flt would be better

[jeff]

We're using 4-flute SGS tools with a Ticn coating.

 

Oh the humanity!!!!

 

Why are you torturing yourself like that? lol

3 flute OSG Blizzards are the shizzit in Aluminum.

They make 2 flutes also, but I personally prefer 3 flute style.

 

Bright finish!

 

or

 

THESE which are very good and a great price.

 

[#Rekd™]

+1 on the variable flute endmills.

[Marshal]

I would think the "old machinist" should know better than to try and slot Alum with a 4 flute E.M. Switch to a 3 or 2 flute and get those RPM's ^^^^^

 

you'd think so, wouldn't you? He's pretty old school though, and very set in his ways.

 

 

Oh the humanity!!!!

 

Why are you torturing yourself like that? lol

3 flute OSG Blizzards are the shizzit in Aluminum.

They make 2 flutes also, but I personally prefer 3 flute style.

 

Bright finish!

 

or

 

THESE which are very good and a great price.

 

because I don't buy the tools unfortunately, our machinist does. He gets most of them from McMaster and orders what he knows rather than trying anything new. I'm only running the mill for a week because he's on vacation, so I don't want to change anything without letting him now

[JAMMAN]

you'd think so, wouldn't you? He's pretty old school though, and very set in his ways.

 

I got one of those also, most of the time I could hug him and sometimes I want to shoot him. No presetting mill tools, he insists on a .004 shim stock one at a time so if I want a pocket an exact depth I have to program it at least .004 deeper. Rapid is always on 25%.

 

I took over a department with 3 existing employees, all 3 have their own circus acts.

 

If ramping in with a 4 flute it has to be a shallow long ramp, I've scraped a few boogers accidentally with a steep ramp. Dang a plunge is almost better, or a peck drill cycle to define an entry point. I plunge rough sometime using drill points and a drill cycle. 3 FL or 2 FL is the way to go but if you think chip evacuation is the issue nothing like a stronger stream of coolant. Pinch it with a smaller diameter tip and point strategically.

[Matthew Hajicek - Singularity]

No presetting mill tools, he insists on a .004 shim stock one at a time so if I want a pocket an exact depth I have to program it at least .004 deeper

 

Then he should be compensating .004" for the shim. How ya gonna hold tenths if your tools aren't even set right?

[Matthew Hajicek - Singularity]

Why are you torturing yourself like that? lol

3 flute OSG Blizzards are the shizzit in Aluminum.

They make 2 flutes also, but I personally prefer 3 flute style.

 

Bright finish!

 

or

 

THESE which are very good and a great price.

 

Anyone try either of these in copper?

[jeff]

Yes I use both in C110 Copper, they cut really good.

[JAMMAN]

Then he should be compensating .004" for the shim. How ya gonna hold tenths if your tools aren't even set right?

 

In his defense we rarely do tenth work, but I would like to do thousandth work and 4 is too much for my taste. It isn't difficult to hold plus or minus one or two on a mill.

 

I would rather set everything with a gage and add one offset for the part Z just like setting X and Y.

 

I have some ideas for the department but are waiting for the right "time" to drop bombs.

 

Hard to get support from upper management being since they have never been in manufacturing they don't know they could spend less money per part. The machining game is new and like magic to them. If it happens it is good. It's me and maybe 2 more people in the place that can clearly see what is actually happening.

 

Didn't mean to hijack the thread, sometimes I really wish I worked someplace else.