CNC PCB milling

NeverDie

@neverdie Can you run a stock GRBL build on RAMPS?

I don't know. I'm planning to use Marlin, which supposedly can exploit at least some of the TMC2130 driver's special features.

After I get all that working, then I may upgrade to higher torque stepper drivers, still NEMA 17 though, as the trinamics can support more current than the A4988's that are on the woodpecker.

NeverDie

I found out that I can buy precision rods and matching linear bearings directly from https://us.misumi-ec.com. Because of the tighter fit, this would, I'm guessing, reduce the deflection on the x-axis.

jeremushka

By checking this discussion i have found a project online called: pcb cyclone factory. I am novice. What do you think about it ?
https://reprap.org/wiki/Cyclone_PCB_Factory

NeverDie

@jeremushka Looks like it might be kinda shakey. Vibration is a notable enemy.

jeremushka

@neverdie yes you are right. I have found a more complete machine. Seems we can use not only for milling. Can be interesting as well. What do you think ?

https://www.banggood.com/2417-3-Axis-Mini-DIY-CNC-Router-Wood-Craving-Engraving-Cutting-Milling-Desktop-Engraver-Machine-240x170x65mm-p-1209292.html?utm_source=youtube&utm_medium=CreativeChannel&utm_campaign=July&utm_content=huangwenjie&cur_warehouse=CN

NeverDie

Looks no worse than what I have .

lamikr

I would like to create pcb's with a 0.5mm pitch as a target and I have tried to follow this thread for hints. Have you @andrew, @NeverDie or @executivul been able to get that done with the milling method?

Then one of the problems with the 2418 that @NeverDie seemed to have was that the machine itself was not stable enough. Do you think that the cheap 3018 work better? For example

https://www.aliexpress.com/store/product/CNC-3018-laser-options-with-ER11-diy-cnc-engraving-machine-Pcb-Milling-Machine-Wood-Carving-machine/424291_32806004900.html
or
https://www.amazon.com/Control-Machine-Engraver-Controller-Extension/dp/B07KYH6BTK/ref=sr_1_6?ie=UTF8&qid=1548751586&sr=8-6&keywords=cnc+3018

andrew

@lamikr pls see one of my very first test I made after I built my cnc. check the TQFP100 footprint.

for me, the cnc2418 was good choice. with proper assembly it is very stable and its output is stable.
I was using the cnc for designs down to 10mil traces without any issue.

so, I have good experience with my low cost cnc but do to the lack of hands-on experience with other devices, I cannot compare or recommend others.

dennisc

Hi everyone,

can someone help me pick out what to order from amazon.de?

I would like to order a 3018 pro, but which one?

What drilling bits would I need to order to mill PCB?

Any help much appreciated!!

sundberg84

@dennisc - I think its a matter of taste and preference, but there is 728 posts in this thread, many describing the pro and cons with different drillbits and mashines. Since its DIY its very hard to tell exactly what to pick - atleast for me - but lets see if someone else is bolder.

dennisc

@sundberg84

I know there are so many posts!

I am under a bit of time pressure and can't wait for aliexpress or bang good, so I was hoping somebody just ordered something off amazon. (and I could copy that).

I am interested in the 3018 Pro, that on looks good enough price wise at least. But maybe had an experience with Sainsmart or something else.

Other important reason is that there have not been many posts in the last months in this thread.

dennisc

I have bought a 3018 Pro and put it together today.

I'm now trying to find out how to calibrate it, any tips would be awesome!

Im using GBRL control.

thanks!

dennisc

Ok calibration was quite easy.

I managed to get the x, y and z axis zeroed. Only thing I am wondering is this:

I can see my file goes 0.2 mm deep. Is there a button to alter the offset?

I found I had to do all kind of fake zeroing to get it deeper!

lamikr

@dennisc I have myself ordered the 2418 from the Jack's store.
I also ordered the parts for Ant's team's PCB machine based on the BOM on
https://bitbucket.org/compactpcbmaker/cpcbm/src/master

It will be intersted in for comparing these two and I think money will not be wasted as other one could in the end anyway be used for drilling if other one does the route milling.

Another thing I am wondering how this will compare to Eleksmaker A3 with 405nm laser and Marco Reps modifications.
https://www.youtube.com/watch?v=ZzO9skEYqwY

Laser is interesting due to it's accuracy but I am worried from the reflected beams. I have only found out so classes for protecting from the beam but would rather like to see a full box made from proper shielding material on top of the Eleksmaker.

Fourths interesting thing is the openpnp based pasta dispenser and pick and place machine.
https://hackaday.io/project/165743-foxbuild-pnp
https://mcuoneclipse.com/2018/06/26/building-a-diy-smt-pickplace-machine-with-openpnp/

dbemowsk

@lamikr said in CNC PCB milling:

Laser is interesting due to it's accuracy but I am worried from the reflected beams. I have only found out so classes for protecting from the beam but would rather like to see a full box made from proper shielding material on top of the Eleksmaker.

Fourths interesting thing is the openpnp based pasta dispenser and pick and place machine.
https://hackaday.io/project/165743-foxbuild-pnp
https://mcuoneclipse.com/2018/06/26/building-a-diy-smt-pickplace-machine-with-openpnp/

I made an enclosure for my 3D printer in which I had a plexiglass panel for the door. Not long ago I made a mod for my 3D printer that allows me to change to different tool heads. https://www.thingiverse.com/thing:3407486

One of the tools is a 6 watt laser module. I got a piece of this to replace the plexiglass on the door of my enclosure. It is rated for the wavelength of my laser module which is 450nm. https://jtechphotonics.com/?product=445nm-laser-shielding This might be a bit small if you wanted to make a complete cover made out of this stuff though.

lamikr

@dbemowsk Thanks for the shielding material tip, I may buy it later if starting to work with 0.5w 405nm laser for engraving. (Some safe enclosure definetly needed)

In the meantime I have not constructed my CNC 2418 from Jack's store and tested that I can control it by seding the g-gode commands from terminal. I have not yet tried to workflow from Kicad, to flatcam and from there to bCNC.

Original GRBL firmware was 0.9j but I managed to upgrade it to v1.1h over USP without need for using another arduino as a ISP programmer and wiring it to woodpecker. Arduino-ide did not detect the board automatically but the flashing to grbl 1.1h worked with a following command out of the box on my linux by using a following avrdude command:

avrdude -v -C/etc/avrdude/avrdude.conf -pm328p -carduino -P /dev/ttyUSB0 -D -Uflash:w:grbl_v1.1h.20190825.hex

This thread is so long that it takes lot of time to try to find all important steps. But what I have gathered is that 3 most important things that I am still missing before trying to mill are the

auto leveling
What I read, this should be easy with gBNC. Mostly connect one wire from the drilling bit to A5 pin in woodpecker and another from woodpecker's ground to pcb.
Current adjustment for all three A4988 motors.
If I understood correctly @andrew and @NeverDie both changed that from 0.6A to 0.9A? Can that be done only by rotating the potentiometer on a4988 driver boards or do I also need to add some resistors?
End stops modules? Could them be connected somehow to woodpecker?

NeverDie

Looks like the price on more precise equipment has come down:
https://www.aliexpress.com/item/32889386703.html?spm=a2g0o.detail.1000014.25.50f15e323iLiE4&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.13338.141931.0&scm_id=1007.13338.141931.0&scm-url=1007.13338.141931.0&pvid=6d201006-5b15-41db-bc2e-2f9421010139

Either this or a more classic mill setup is probably the most cost effective for cutting pcbs more accurately. It's the twisting slop that most limits my current CNC's PCB fidelity.

NeverDie

On my previous attempts, I wasn't aware there existed any options for milling PCB's beyond just v-bits. Now it seems that there's quite a range of actual end-mill bits in diameters as narrow as 0.05mm!

https://youtu.be/MaErWEukcGI

They look like this:
alt text

From what I've read, when using end mills with less than 100 micron cutting diameters, it's recommended to do step cutting, due to the delicate nature of the bit. That's fine with me: once I set up the machine with a PCB blank, I can walk away and come back when it's done.

Anyone tried using end mill bits like these for milling PCB's, and if so, how do they compare?

niallain

@NeverDie I've got this one several months ago, I couldn't say it's a good one though.
here is the list of drawbacks I've had/have:

spindle fixed speed 12000RPM. I added automatic circuit breaker to it so it won't put home on fire when it rams into the table. (threw away DC connector on top as it wasn't reliably holding both sides to begin with and then it was burned a bit after spindle stall). Runout is about 50um. + whatever collet would add (cheapest ones from aliexpress were disappointment in a range 50~100um, so I've got precision one locally)
The only thing I'm going to invest into this machine is 24K spindle + vfd with small runout. (it just arrived but still unpacked, it will need adapter plate to mount it on Z plate, hopefully I'll make something with adjustable tilt to simplify tramming)
it was poor assembled, one has to disassemble and put it back properly tightening screws and making sure belts are not loose (that solved lost steps issue)
it uses lead screws with bronze nuts like in 3D printers and a plastic spacer between nuts (to counter backlash).
axis plates are attached to nuts via that same plastic spacer (not sure how it would do with milling aluminium)
there was (still is) some backlash (~40-60um) left after tightening nuts,
one could tighten it further but that would come at cost of lower speeds as no-name steppers start stalling (currently I have 2300mm/min max on XY plane, and one would wish for more rapids if one would wish to try milling plastics)
squaring it is nightmare, basically the only option you have is adjusting X pillars and try to square XY and YZ at the same time (and there isn't much space to play with it). For tramming spindle on XZ plane, I had to move up one side of X support plate as there isn't sufficient play in spindle mount and then level sacrificial board to make X axis square to the table.
As result of several iterations, I've got ±40um difference in hight across the table. XY axises still not square ~0.5mm on opposite sides of of the table on X axis, but I don't have heart to repeat whole procedure again (yet).
controller dial is way too sensitive, so I practically don't use it at all. Ribbon cable to SD card fell appart, USB connector for PC doesn't work reliably (but mostly works if you got it in working position).

The whole setup was bought to prototype PCBs and later on learn how to mill other stuff (plastics/aluminium) for casing prototypes.

So far I've managed to mill reliably 0.3mm isolation paths with 60*0.2 engraving bit (but as you did, I've redesigned board with wider traces to reduce failure chances). In Flatcam, I had to add runout value to tip diameter to avoid track thinning. Perhaps I could do more fine traces now (after all the tuning) with more fragile 30 or 15 degree bits, but I won't try till I get current project out of the door (at least hardware part of it).

and here is my 1st attempt to mill the case part

NeverDie

I received one of the 0.2mm end mill bits, so I'll be having a run at it with that sometime soon. To give it the best chance, I plan to bed level with some large diameter endmills first, as I haven't tried that before and maybe it will help. Looking forward to it.

Wegster has a series of impressive videos on youtube that are an inspiration that this is actually possible to do with fairly ordinary looking equipment (though they charge a small fortune for theirs):
https://www.youtube.com/watch?v=cCm-UL-dCEc

Maybe there's more to it than meets the eye? Makes me wonder what exactly they're doing in order to accomplish it so perfectly.

An alternative might be to connect a sharpie type pen and plot that way as a prelude to chemical etching. I haven't wanted to do that, but it's a fallback that might work to get fine pitch etches.

Hackaday did a very insightful analysis of "the mother mill" which explained why it is surprisingly good at milling PCBs despite it's having a largely plastic frame construction:
https://hackaday.com/2016/08/02/the-othermill-vs-import-a-technical-comparison/
Usually success begets knock-offs, but I can't say that I've noticed any knockoffs of the OtherMill.

I'd really like to have a machine with an automatic tool changer, where I could just launch it and come back when it's totally done with everything. I'm surprised that capability hasn't yet become more widespread.

CNC PCB milling

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