Drilling holes on cnc

[dfox1787]

dfox1787,

Perhaps I missed something, but I don't see any reference to the material you want to drill. That is very important in my opinion. The fact that you have ER collet is not a problem, you just need to buy a set of collets since those are not like a drill chuck, you need a number of those. I have ER11 so I can't drill anything larger than 7mm with drill bits, which is OK for my needs, but of course, even I must have a large number of collets. I am drilling holes from 0.3mm up to 6mm with different drill bits, depending on the material I need to drill in, which can be PCB, aluminium or plastic. Of course, wood and similar is also OK. I also don't know why you feel you are limited to 10k rpm. The recommended lowest rpm for high speed 24k rpm spindles is 6k rpm but I have absolutely no problems to go below that as well.

Drilling starts at 2,5 minute mark.




In that clip I am drilling with different, standard (I think Cobalt) spiral drill bits, from 1.5mm to 5mm and in that video the lowest rpm is 5800rpm, but in aluminium I went as low as 3800 rpm also and that caused no issues at all. What is important is to use sharp and good quality bits. I use no liquid cooling at all and have no issues with welding, but if I have to drill many holes I let the bit to cool now and then.

Drill aluminium mainly. However i would need collets that would fit say 2.5mm drill bits so the hole can be tapped. Myabe i just need some high quality bits for the cnc. Its just the high speed of the spindle that concerns me.

[A_Camera]

I have a set of collets and 2.5mm is one of them. Drilling in aluminium it is important to spot drill first. I normally use a 6mm 90 degree spot drill for that purpose, and after spot drilling (not resetting the machine so that I keep the zero positions) I just change to the right bits and start the drilling. Just make sure the spindle can't start spinning when you are changing bits so that you are safe.

[magicniner]

Drill aluminium mainly. However i would need collets that would fit say 2.5mm drill bits so the hole can be tapped. Myabe i just need some high quality bits for the cnc. Its just the high speed of the spindle that concerns me.

You don't need to Drill to get accurately sized and positioned holes, you can mill with an interpolated spiral tool path, a 2mm endmill will suffice for a 2.5mm hole, with air and lube it may be the ideal solution with a spindle with only high speed capability.

[dfox1787]

You don't need to Drill to get accurately sized and positioned holes, you can mill with an interpolated spiral tool path, a 2mm endmill will suffice for a 2.5mm hole, with air and lube it may be the ideal solution with a spindle with only high speed capability.

nice ill give that a go on some scrap aluminium.

[A_Camera]

nice ill give that a go on some scrap aluminium.

Give it a try, but expect to break many small bits. In my opinion it is better to go out and buy some good quality 2.5mm spiral drills. Drilling is much faster and 2.5mm is not that expensive or difficult to find.

[dfox1787]

Thank you. I was worried about breaking bits. I thought about spotting and then using bench drill.

Do you know anywhere to get descent spiral drill bits?

Give it a try, but expect to break many small bits. In my opinion it is better to go out and buy some good quality 2.5mm spiral drills. Drilling is much faster and 2.5mm is not that expensive or difficult to find.

Sent from my SM-N910F using Tapatalk

[A_Camera]

Thank you. I was worried about breaking bits. I thought about spotting and then using bench drill.

Do you know anywhere to get descent spiral drill bits?

Sent from my SM-N910F using Tapatalk

Yes, but that won't help you. I am buying mine locally in Sweden in a shop near me.

[magicniner]

Give it a try, but expect to break many small bits.

Crikey, you must have issues with your CAM or machine!
I've never broken a milling cutter when using a helical path to cut a hole slightly larger than the cutter up to 5 diameters deep. Provided you use air nozzles to clear chips it's a very low stress job for the cutter, climb milling with a very small step over and DOC, it's a quick process too and ideal if your spindle only does high speed.
This strategy also works well for jobs where it's faster to machine an appropriate starter or guide hole then finish on a manual drill press.

[A_Camera]

Crikey, you must have issues with your CAM or machine!
I've never broken a milling cutter when using a helical path to cut a hole slightly larger than the cutter up to 5 diameters deep. Provided you use air nozzles to clear chips it's a very low stress job for the cutter, climb milling with a very small step over and DOC, it's a quick process too and ideal if your spindle only does high speed.
This strategy also works well for jobs where it's faster to machine an appropriate starter or guide hole then finish on a manual drill press.

The comment was to somebody who has no experience with it. Yes, I broke a few at the beginning... Anyway, yes, some times it is practical and may even be faster, but most times drilling using drill is faster than through milling. It is also easier to drill deeper holes using spiral drill than milling them using long mill bits. Especially small holes, like he needs to drill, I'd not bother milling. Large holes are different.

[Chaz]

I would also recommend that if you need to do anything larger than 4mm or so (with a 2.2KW type spindle), consider milling the holes. If you need accuracy, do them slightly undersize and then ream them.