Tool wear rate...

[Davek0974]

I am running 2mm and 5mm YG1 carbide single-flute end mills on my mini-mill, I am seeing crater wear which is causing the cut quality to fail in short time i think.

I am milling aluminium and use mist lubricant,.

How long should a carbide tool last in aluminium? These have probably only 15-20mtrs of cut length on them.

Any tips??

[mekanik]

Hi Dave
You will have to give the guys a bit more information if they are going to help.
What machine are you using/ feed rate/step over and spindle speed plus depth of cut @ least.
Regards
Mike

[Davek0974]

Of course

Machine is a DIY mini-mill router built specifically to cut aluminium. Spindle is a 2.2kw water-cooled job.

My 2mm tool normal feed/speed is 24000rpm, 370mm/min, mostly profiling, 0.2mmWOC, various DOC - cutter is rated to 3mm maxDOC. 0.01295 chip-load.

But the feed rate in the makers data is
23000rpm, 0.065 chip-load, 1500mm/min

Now this chip seems frighteningly big for a small tool, i tried it and it snapped after a short time.

I just got a reply from the dealer and it seems runout may be a problem here, i will measure this tonight - its quite possible as all my stuff is not top-end tooling so could be bad spindle, bad collet, etc.

Still, 1500mm/min on a single-flute tool slotting is pretty harsh i think?

[spluppit]

Dave, can you give some more info? Still not enough to be getting on with. Firstly can you define what you mean by crater wear and an image would be even better. Also the conditions you are cutting in, the job the set up, the material, clamping etc. Again even better a image of the job you are working on, on the machine would help a lot. It can sometimes be a small combination of various things that lead to problems that are hard to define by single bits of info.

I don't see those speed and feeds to be a problem considering the recommended rpm, but it maybe a problem for your machine. Remember the recommended feeds and speeds are like fuel economy figures advertised by car manufactures. Its best case scenario in the best possible conditions that can not be repeated in real life. Your machine designed for ally or not if its still probably a inherently weak gantry style machine by the very nature of gantry style machines you are fighting the odds from the outset but that does not necessarily mean it is the machine. Again its down to cutting conditions. More info will help a lot.

[Boyan Silyavski]

Then it must be the runout or rigidity issues. Did you check that feeds in HSMAdvisor? I mean what deflection you have at that speeds and DOC?


What is the exact cutter specification? Could you pass a link to see it? Or give here the dimensions so i can check for myself?

[Davek0974]

I had a quick look tonight at runout, from what i can measure there is no runout in the spindle socket (ER20) so thats ok, but the collet - thats another story!


I put the 2mm tool in with about 20mm shank protruding, near the collet there was 0.1mm runout - pretty bad, further down the shank near the flutes it measured 0.1mm again. I marked the retaining nut and spindle at the point with the largest reading and rotated the collet in the socket 180deg.


The nut was tightened back to the same point and the measurements taken again. This time the high point had moved with the collet but was the same.

Sounds like a totally junk collet :)
Will find some decent ones i think.

This is the cut spec leaflet, the single-flute E5E47 range.

19480

The material is firmly clamped, no movement, either 3mm or 5mm thick.

[Robin Hewitt]

there is no runout in the spindle socket (ER20) so thats ok, but the collet - thats another story!

Did you buy standard or close tolerance collets?

[Davek0974]

Standard - all my stuff is pretty much "standard" ;)


Yesterday i found one of the right size with 0.03mm runout so i'm using that one for now.