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CNC 3018 PCB drill bit break
Good day everyone,
I ask for help with my CNC 3018 PCB board milling.
I’m new to CNC 3018 as beginner. I tried mill for PCB to made own Diy Z probe from YouTube,
YouTube link:
https://www.youtube.com/watch?v=l9o6ZUjb3k0 - YouTube but PCB End Mill break
I downloaded Z probe from this link, I opened fusion 360 and save as NC file for UGS.
I successfully tested to mill on wood with V cutting bit, the I started mill with PCB mill bit size is 0.8mm, but it don’t cut the PCB board deeper. I tried to made deeper and it is worse to cut and PCB ugly look.
Check image below
Attachment 30437
Re: CNC 3018 PCB drill bit break
Quick question - is that actually an end-mill/slotting cutter?, or a (very common) 0.8mm drill bit?
Next, what spindle speed are you operating at?, and how high can you go? Coupled with that, what's your depth-of-cut, and what are your X/Y feed rates.
Looking at the image, I'd be concerned from the pattern traced by the cutter that you're getting a lot of tool deflection, which could be symptomatic of too slow a spindle speed and too high a feed rate. But there's people with more experience than me on here that can offer more substantial advice.
Re: CNC 3018 PCB drill bit break
I am milling PCB with 0.1 mm 30 degree V bit at 24k rpm. I think that is better than end mills. Anyway, PCB is considerably harder than wood so you need high rpm, good cutter and just right feed rate. Of course, you also need a machine with low vibration and good rigidity. But if you don't have that, then you can try to lower the feedrate. It is a bit of a trial and error, but best is to start slow with the highest rpm you can get, not too shallow cuts, try 0.4 mm since most copper layers are 0.35 mm so that should be good enough. Also, use some sort of waste board between the PCB and the table. I use MDF which is levelled.
Your picture shows that you have other problems too. Did your machine run away uncontrolled?
Re: CNC 3018 PCB drill bit break
Any cutter with a length/diameter ratio that is extreme is going to deflect.Maybe you should be searching for something just long enough to achieve the desired depth of cut.
Re: CNC 3018 PCB drill bit break
Quick correction there, standard 1oz/ft2 copper is 35 micron (0.035mm, not 0.35).
0.4mm is a bit aggressive, also for isolation routing I’d expect a smaller diameter cutter for any standard 0.1” or less packages. OP, start with a shallower cut.
Some of the traverses are suspicious, but i(blindly) wrote those off as OP playing with settings, looks to have moved to board reference with z at zero, all part of the learning curve. If I’ve been presumptuous then apologies to OP.
Last thing that OP needs a heads up on is that copper laminate is anything but flat. A good first stab is some form of pressure foot to hold the substrate onto the bed, but that assumes a flat and level bed… those need to be established before you’ll get any good result.
Re: CNC 3018 PCB drill bit break
For info, I’ve done reasonable isolation routing using 0.3mm dia end mills. Those have a cutter length about three mm and will snap if you look at them wrong. But great cut compared to v cutters, but together with their fragility are wickedly expensive. To OP, dial out all your other problems before entering the world of exotic cutters.
It’s this experience that resulted in the question whether the image of the snapped cutter is an end mill or a PCB drill. The cutter length looks to be too long for a cutter suited to PCB, but your experience may vary
Re: CNC 3018 PCB drill bit break
Quote:
Originally Posted by
Doddy
Quick correction there, standard 1oz/ft2 copper is 35 micron (0.035mm, not 0.35).
0.4mm is a bit aggressive, also for isolation routing I’d expect a smaller diameter cutter for any standard 0.1” or less packages. OP, start with a shallower cut.
Some of the traverses are suspicious, but i(blindly) wrote those off as OP playing with settings, looks to have moved to board reference with z at zero, all part of the learning curve. If I’ve been presumptuous then apologies to OP.
Last thing that OP needs a heads up on is that copper laminate is anything but flat. A good first stab is some form of pressure foot to hold the substrate onto the bed, but that assumes a flat and level bed… those need to be established before you’ll get any good result.
You are right, I am sorry, I left out a zero. Of course, I meant 0.035 mm for the copper layer and the milling depth I use is 0.04 mm. Never went deeper than 0.07 mm.
Yes, it is VERY important that the table is flat and levelled. I face the MDF every now and then (basically almost every time) but I don't use any double sided tape because that is making the table uneven and facing pretty pointless. I only use tape on the edges, in my opinion that's enough and better than screws or anything which pushes the edges down on far too small area because that will result in raising the centre of the PCB. I think it is better to apply holding force on all edges using tape, but of course, a vacuum table would be even better. Some people use super glue, I don't. I think super glue would work well also, but removing becomes a PITA, so I won't use that. I only buy quality PCB and so far I always found them flat enough. When I zero the cutter I try to find the lowest point on the PCB to reference to, that way even if some parts are slightly higher, the track isolation will be OK.
I made a video some years ago, in this video I mill down to 0.07 mm in two passes, but lately I mill in one pass and only to 0.04 mm depth. I the video I run the spindle at 22k rpm, which lately is 24k. I found that less tips are broken with higher rpm.
https://youtu.be/nrW6Hq6V3VY
BTW, I also no longer use Eagle. I think that the free version it is too limiting. I use EasyEDA and FlatCAM today.
Re: CNC 3018 PCB drill bit break
Has anyone tried auto-leveller for milling PCBs?
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Re: CNC 3018 PCB drill bit break
Quote:
Originally Posted by
NB70
A long time ago I tried one auto leveller, but they all work the same. Then I realized that it is better to spend time on levelling the machine and facing a piece of MDF plus using quality PCB material than hiding machine errors and deficiencies through using auto leveller.
BTW, I am not impressed by the with / without auto leveller.
Attachment 30439
There are hardly any tracks left and the left side still seems to have some issues, so I think that there is something wrong with his machine.
There is an auto leveller built into UCCNC also, but I never tried that one.
Re: CNC 3018 PCB drill bit break
Quote:
Originally Posted by
NB70
I don't always agree with A_Camera, but in this case I support everything he says here - get your bed level, then try to get your substrate only the bed. Anything else is sticking plaster, and if you have a bowed board then autolevelling isn't going to work.
