Chip Welding

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Harold_V
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Re: Chip Welding

Post by Harold_V »

ctwo wrote:Harold, maybe I've watched too much youtube
I gotta say, that's pretty impressive!
You shouldn't expect similar performance unless you have similar equipment. The power and rigidity of the machine in use allows for greater capabilities. And, ductile iron machines very nicely----and would not have issues with chip welding. Carbide is far more rigid than HSS, which doesn't hurt the cause, either. All in all, proves me wrong, although I expect it wouldn't happen with smaller end mills.

Harold
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ctwo
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Re: Chip Welding

Post by ctwo »

End mills - perhaps a question better for another topic, but why would I have so many end mills with flute lengths multiple times their diameter?
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GlennW
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Re: Chip Welding

Post by GlennW »

ctwo wrote: but why would I have so many end mills with flute lengths multiple times their diameter?
Because you may need to take a finish cut of a thousandth or two around the periphery of a part by climb milling with some sort of coolant or lube after you have stepped down to final depth. (In the context of small end mills)

Unfortunately, you are not going to find hard numbers to cover every scenario for every cutter when milling.
Glenn

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Harold_V
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Re: Chip Welding

Post by Harold_V »

Yep! What Glenn said.
Are you familiar with die sink end mills? Ridiculously long, and of no real value unless one requires the added length to achieve deep cuts. They chatter like crazy, but applied properly they provide the necessary cutting action that, otherwise, may not be possible. Said another way, just because an end mill has an inch of flute doesn't mean it can be blindly applied to a cut and expected to withstand the demand placed upon it. Good sense is required when you make choices with end mills.

Harold
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ctwo
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Re: Chip Welding

Post by ctwo »

I'm not familiar with die sink end mills, but google image search reveals some that look like they would work well for engraving...and others that look a bit like easy outs, or tapered ball end mills, but not very long.

I have some that are about 1/8" diameter and 2" long flutes (or around 10 diameters).
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BadDog
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Re: Chip Welding

Post by BadDog »

Tapered end mills are used in die making to provide draft relief and extrusion bearing relief. Not much use in general mill work.
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oldvan
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Re: Chip Welding

Post by oldvan »

Is HSS a better choice for aluminum?
SteveM
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Re: Chip Welding

Post by SteveM »

oldvan wrote:Is HSS a better choice for aluminum?
Here's a shot of one of Curtis' polished inserts for aluminum:
Image

People have said that these things are so sharp, you can cut your fingers on them.

I think that these could do a pretty good job.

Steve
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Harold_V
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Re: Chip Welding

Post by Harold_V »

oldvan wrote:Is HSS a better choice for aluminum?
Depends. If chip welding is an issue, there are available HSS end mills ground expressly for aluminum. They are polished, and have greater relief. Lube for the cut would still be advisable, however.

Deep depths of cut should almost always benefit by the use of carbide, if for no other reason, carbide is much "stiffer" than HSS. That would not be true if the machine in question is not robust, however. Any transient movement in carbide machining tends to destroy cutting edges.

Stiffness is why solid carbide boring bars are so popular. Cuts that border on the impossible with HSS can be taken in stride with carbide bars. I expect that you can achieve much the same results with end mills. I can think of no personal experiences to verify my opinion, however.

Part of the problem with comparing carbide against HSS in lathe work is that carbide insert tooling can be negative rake, which is completely different from machining with positive rake. Negative rake inserts are generally not ground, so the resulting surfaces are not as smooth as diamond ground positive rake inserts. That would not be true of carbide end mills, which are, today (thanks to CNC cutter grinders), ground from solids, so the resulting surfaces are relatively smooth, and should yield acceptable results in lowering chip welding. The added stiffness would certainly be a great benefit.

Harold
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BadDog
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Re: Chip Welding

Post by BadDog »

I've got largish (3/4" and 1") HSS 2 flute end mills that eat aluminum like you wouldn't believe. Using WD40 from a bulk can, I've had no problems with welding or chip compaction. They are razor sharp, polished on the flute rake, and made for rapid aluminum chip evacuation. When you crank them as designed, the ejection of chips looks somewhat like a sprayer on a water hose, hitting my containment wall and piling up like a gopher mound. For smaller sizes, I've got some 2 flutes down to may 1/4" IIRC that are also made for aluminum. The limit on those is gullet size and chip compaction, but they work well.

I've also got 2 flute carbide EMs, almost exclusively in smaller sizes. Again, chip evacuation is the problem, particularly when dealing with typical turret mill spindle speed limitations. I'm not entirely sure, but I'm pretty sure every one I have broken was due to crowding it and chips packing up.

I used the big HSS cutters for bulk aluminum removal up until I got a 2" 6 insert Mitsubishi face mill. The inserts are square polished and dished with sharp edges and set square so it will cut a vertical wall. That thing is insane. The chips look like mini potato chips if you crank it like it really likes. With the spindle turned up, I can't crank the table fast enough, so I use the power feed, sometimes on rapid. It looks like snowing with huge flakes.
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12L14
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Re: Chip Welding

Post by 12L14 »

One word - ethanol ;)
Tool&die maker since yesterday ;)
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Re: Chip Welding

Post by Inspector »

So if you have had the misfortune of loading a cutter up with chip welded aluminium :cry: is there any way of removing the aluminum from the cutter?

Pete
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