Drilling holes on cnc

[Wal]

>I know my spindle has certain collet sizes so standard bits are unlikely to fit.

Why not - you're using an ER system, aren't you?

Anyway, as m_c said, there are plenty of options out there - a cursory search brought this up:

https://www.cadem.com/single-post/cn...l-helix-angles

Not a bad place to start. As per Chaz's advice - yep, it can be a bit hit and miss with the 2.2kw Chinese spindles - you don't want to go too fast and burn up the drill, but you really don't want to drop much lower than 9krpm as you risk stalling the spindle...

One thing I would say: make sure you spot drill first..! If you're using standard drill lengths then you can expect a bit of a squeal on the first peck, but that should disappear once the drill gets a bit deeper... Here's a vid of my machine drilling out a section so that I wouldn't have to deep slot (fast forward to about a minute in). I'm sure I could've gone a bit quicker, but you know - when you find something that works you tend to keep it that way..!



Good luck.

Wal.

[m_c]

For general purpose drilling, I'll normally get Cobalt drills. More durable than pure HSS, but typically slightly more brittle (not as brittle as pure carbide though!), and can handle higher speeds than pure HSS (but no where near as high as pure carbide).
Polished ones for aluminium, and suitably coated ones for steel.

Key thing is to ensure you are within the speeds/feeds specs for the drill, and as Chaz/Wal say, with Chinese spindles that can be a problem. You'll likely get better results on larger holes by either pre-drilling then milling to size, or just helix milling.

Spot drilling depends on what you're doing. I generally only use stub drills with split point (or whatever the manufacturer wants to call their self-centring drills), which I'll never spot drill first. However anything I need to use any longer a drill on, I'll generally spot first.

[wiremonkey]

Hello,
Drilling accurately placed holes is not easy. I strongly suggest screw length bits, the shorter the better, to eliminate deflection. I'm fairly new to cnc and posted a video of my experiences drilling holes here: https://www.youtube.com/playlist?lis...jVPFZmTCBEeF2y
I should add that I bought an old 3/8" Jacobs chuck off of ebay and a straight 1/2" shaft for it. I chucked it up in a precision collet on the router and damn if it doesn't work perfectly. For drilling operation, no more changing collets or needing collets for every different size. I highly recommend it. I show it in the video I linked to above.
Cheers, Tyler

[routercnc]

I use a mix of 3mm HSS twist drill in a standard 3mm collet to pilot holes (no spot drill), and then finish on the drill press. Or interpolate holes using a 6mm end mill ideally with a spiral toolpath. Fusion is great for this.

These end up being very accurate although for bolt clearance holes I often go for bolt nominal diameter plus 0.5 mm to give some allowance in assembly.

See examples in my videos here:

4:40 and 10:40
https://www.youtube.com/watch?v=wqff3IZZWvw

[dfox1787]

>I know my spindle has certain collet sizes so standard bits are unlikely to fit.

Why not - you're using an ER system, aren't you?

Anyway, as m_c said, there are plenty of options out there - a cursory search brought this up:

https://www.cadem.com/single-post/cn...l-helix-angles

Not a bad place to start. As per Chaz's advice - yep, it can be a bit hit and miss with the 2.2kw Chinese spindles - you don't want to go too fast and burn up the drill, but you really don't want to drop much lower than 9krpm as you risk stalling the spindle...

One thing I would say: make sure you spot drill first..! If you're using standard drill lengths then you can expect a bit of a squeal on the first peck, but that should disappear once the drill gets a bit deeper... Here's a vid of my machine drilling out a section so that I wouldn't have to deep slot (fast forward to about a minute in). I'm sure I could've gone a bit quicker, but you know - when you find something that works you tend to keep it that way..!

https://www.youtube.com/edit?o=U&video_id=uwDesJPd6a0

Good luck.

Wal.

Hi Thank you for this.

Ill take a look into those bits. My spindle is the ER system. The min rpm i can get is 10000.

The link you sent me takes me to the video edit part on my youtube. Id love to see the video though

[Wal]

The link you sent me takes me to the video edit part on my youtube. Id love to see the video though

Ah - I copied link from my creator page - here you go (not that interesting, to be honest..!):

https://youtu.be/uwDesJPd6a0

All the best.

Wal.

[wiremonkey]

Wal, what are you using for coolant and how are you catching it? Would be cool to see a wide shot and overall setup view of your CNC.

[Wal]

Wal, what are you using for coolant and how are you catching it? Would be cool to see a wide shot and overall setup view of your CNC.

Here's a link to a handful of pics on an old thread. Added a couple of extras since, but the machine itself remains the same...

http://www.mycncuk.com/showthread.php?p=55068

Sent from my HTC One M9 using Tapatalk

[A_Camera]

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.

[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.