Aluminum - just something weird

[a_johnson]

Not that it is a critical question, I am just curious...

I cut holes in 0.15" 5052-H32 aluminum cabinet plates, lots of them, they cut nice, smooth finish. But I had one plate and only at a certain position where the aluminum melted, rough edges, the cut looked horrible. What could cause that? Impurity in the manufacturing of the plate? My CNC had not gone off course since the next cuts were bang on. I just done understand how that could happen.

Thanks for any comments.

Al

[txcncman]

Most likely the cutter is getting dull and, dull or not, aluminum chips were sticking to the cutting edges. The only way to know for sure for an intermittent problem like this is never take your eyes off the cutting tool.

[DMF_TomB]

cutting oil is used to help prevent chips sticking to flutes.
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in some situations a chip is stuck to cutting edge but comes off if given time to cool.
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some people brush on or spray on a thin coat of oil on aluminum they are cutting.
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if nothing else when cutter gets extra hot the smoke will increase and this tool can be used for indicating where cutting conditions may need adjusting.
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many metals have inclusions mixed in metal, with aluminum this is usually aluminum oxide pieces like sand paper grit. this effects cutter
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use end mills made for aluminum. they have a higher rake and helix and are sharper with usually polished flutes both of which helps with chips sticking. some coatings also help to lower surface friction and help prevent chip sticking

[a_johnson]

Ahh a stuck chip, that makes sense. I have been doing my cutting dry with an air jet to help cool so the odds of a stuck chip is high. Thanks for clearing up my mystery.

Al