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Author Topic: 1/4" 2 Flute End Mill  (Read 3535 times)

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Re: 1/4" 2 Flute End Mill
« Reply #20 on: January 13, 2016, 03:34:55 PM »
Hi Terry
Well, yes , and no (imho).
Rubbing is seriously bad of course, but having intercepted a few cases just before the cutter broke (really), I don't think it is that simple.

What I have seen ias a build-up of aluminium at the tip of the cutter - little chips sticking to the carbide. It is known that some carbides have a slightly rough, almost porous surface, and the aluminium can get wedged into the pores. That's at the microscopic level. Then the built-up aluminium starts to rub on the stock, and that does create a LOT of heat and a run-away situation.

Yeah, I kid you not: there was this slightly melted blob of aluminium wrapped around the tip of the carbide cutter! Getting it off was hard: it was really stuck on in a conformal manner. I switched to a polished HSS-Co cutter for the rest of that job - with some pulsed kero/oil mist to keep the cutter wet.

I agree that the sharper edge on a cutter meant for Aluminium works better - a polished flute also seems to help. Some of those 'aluminium' cutters break down quickly when used on steel. The edge is too thin.

It all gets expensive. Now I have cutters labelled 'steel', 'titanium', 'aluminium' and 'plastic', and have to keep them separate. But it seems to work.

Cheers
Roger

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Re: 1/4" 2 Flute End Mill
« Reply #21 on: January 13, 2016, 04:15:05 PM »
YEs cutter FORM can be specific to teh material. Here I use a cutter specifically for aluminum. Very sharp and very polished, most of the time they are colbalt or HSS. Carbide as a last resort.  BUT the root cause is always heat. I have seen some instances where even flood coolant could not cool teh actual cutting surface. It created a steam pocket and the actual tip was not cooled. Most GOOD coolants have a surfactant to break down the surface tension of the liquid to help in those areas.

Yes brass tools, aluminum tools, Titanium tools steel, tools Low carbon steel , and tools Hi carbon steels.  I think I have more money in tools than Machine (;-)TP