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I was using a Roland PNC 2300 and tools similar to this:
https://www.prytec.com.au/product/160/Roland-Engraving-Cutters-for-Aluminium--Brass/
-all now very obsolete!
Attempts at manual control never gave a good outcome, and larger tools (more than 3mm diameter) generally tore the copper free regardless of machine or method of holding.For anything larger / structural / more decorative than a circuit board I would try to teach precision smacking with the correct hammer followed by various grades of abrasive, or advise students to use brass or aluminium as an alternative to copper.
Brass might work - IIRC a brief etch in warm ferric chloride will preferentially remove the zinc leaving a (thin) layer with a high proportion of copper and the appearance of a dull copper finish.
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Yeah, really feels that a shear or guillotine would be the best bet here if I was wanting straight cuts!
Just snapped a 0.8mm corn cob end mill...probably went a little fast.
Aluminium mills pretty well on these small lower powered machines or so i'm told...might have a dabble with that if my single flute test doesn't work, on the off chance it helps with the learning curve. Or brass, as you say.
If I figure it out i'll definitely let you know.
My spindle is about as low powered as it gets and I am only cutting super slow and only nibbling the top 0.1mm with each pass. so whilst its really slow its actually cutting through fine. Its more the incredibly rough cut finish that is the problem. I'm using a 1.4mm corn cob end mill which I think might be the problem. I've read a few people saying the same as you...that 1 or 2 proper flutes with a straight end...so that is what i'll try next.