CNC PCB milling

[NeverDie]

I made some enhancements to the remote used with the CNC Monitor. Among other things, it's now more compact, and the top now has a ground plane (which may help the RF):

The bottom makes most of the connections and will hold the two AA batteries:

[dbemowsk]

@neverdie So I have an odd CNC related couple of questions. Next, when you put a bit in the chuck, do you always bury it in to the base of the bit? When you have your bit in for working on PCBs, what is the distance from the end of the chuck to the tip of the bit that you use?

[NeverDie]

@dbemowsk Is this for calculating deflection?

[NeverDie]

@dbemowsk I haven't been very consistent, but I'd say roughly 7/8 inch.

[dbemowsk]

@neverdie Actually, I am working on my Z axis and am trying to gauge how long I should have my rods. They are currently 8.25 in (209.55 mm). Wondering if there would be any benefit to leaving them that long or shortening them up some more.

This is the spindle frame as I have it designed so far. The blue piece on the motor shaft is just one of the couplers that I bought for the steppers to connect the threaded rods. It is just for looks until I get the chuck.

[NeverDie]

@dbemowsk said in CNC PCB milling:

@neverdie Actually, I am working on my Z axis and am trying to gauge how long I should have my rods. They are currently 8.25 in (209.55 mm). Wondering if there would be any benefit to leaving them that long or shortening them up some more.

In that case, what matters is whether you can raise the spindle high enough on the z-axis to remove the used bit and insert the next one. I wish my z-axis had a bit more height on it. Sometimes I have to move the spindle away from the workpiece in order to get enough clearance for a tool change. I suppose it doesn't help that I'm using a 3/4" waste board. ;)

[dbemowsk]

@neverdie said in CNC PCB milling:

I suppose it doesn't help that I'm using a 3/4" waste board.

Do you need 3/4"? Wouldn't 1/4" or 1/2" work? Do you drill in that far?

[NeverDie]

@dbemowsk 1/2" is probably ideal for my particular setup. 3/4" is simply what I tried first. 1/4" might work, but with less margin for error.

[NeverDie]

@dbemowsk Shouldn't you have some linear ball bearings gripping those z-axis rods?

[NeverDie]

Here is the above PCB after assembly:

As you can see, it offers more potential functionality than the earlier version. It still has a buzzer, which is now mounted underneath the pro mini.

[dbemowsk]

@neverdie FOr starters I am trying 3D printed rod bearings. I';ll see how that goes. The beauty of designing this myself is that I can alter the design whenever I want.

[zboblamont]

@neverdie Di the relocation of the buzzer increase audibility as you were seeking?

[NeverDie]

@dbemowsk said in CNC PCB milling:

I am trying 3D printed rod bearings

What are those? Is it like this?

or this?

[dbemowsk]

@neverdie mine are similar 3D printed ones

[NeverDie]

@dbemowsk what kind of material?

[dbemowsk]

@neverdie I just printed them in PLA and they seem to slide pretty smoothly on the rods, but someone told me that printing them in nylon is better.

[NeverDie]

@dbemowsk said in CNC PCB milling:

printing them in nylon is better.

It would seem so: http://www.craftechind.com/top-5-materials-for-plastic-bearings-used-on-metal-surfaces/

If you had a multi-filament printer, I wonder if you could print the nylon bearing within another plastic piece (e.g. the part that holds the spindle to the z-axis)? That would would be pretty cool and would also save assembly time.

[dbemowsk]

@neverdie the way i have it designed, the printed bearings get sandwiched by a rear plate that holds the bearings and coupler nut that goes on the threaded rod to drive the assembly up and down.

[dbemowsk]

I wasn't home before to get a pic, but here is the layout.

[NeverDie]

Anyone tried Trinamic drivers, such as the TMC2130? They seem to produce superior 3D prints, and so I would guess they would yield some improvement for CNC as well.

So far I've only found two boards that appear to be made for them, a ramps and a rumba:
https://www.aliexpress.com/item/MKS-Gen-V1-4-control-board-5PCS-TMC2130-V1-0-And-Heatsink-stepper-motor-compatible-with/32836389832.html?spm=2114.search0204.3.2.3e5a8105IWdaWH&ws_ab_test=searchweb0_0,searchweb201602_5_10152_5711320_10151_10065_10344_10068_10130_10324_10342_10547_10325_10343_10546_10340_10548_10341_10545_10084_10083_10618_10630_10307_5711220_5722320_10313_10059_10534_100031_10103_10627_10626_10624_10623_10622_10621_10620_10142,searchweb201603_2,ppcSwitch_5_ppcChannel&algo_expid=875aa997-05fe-4eda-9d76-0aaefcaeff83-0&algo_pvid=875aa997-05fe-4eda-9d76-0aaefcaeff83&priceBeautifyAB=0

https://www.aliexpress.com/item/3D-Printer-Rumba-Board-With-6pcs-TMC2130-Stepper-Driver-6pcs-Heatsink-High-Quality-3D-Printer-Parts/32839321651.html?spm=2114.search0204.3.49.3e5a8105IWdaWH&ws_ab_test=searchweb0_0,searchweb201602_5_10152_5711320_10151_10065_10344_10068_10130_10324_10342_10547_10325_10343_10546_10340_10548_10341_10545_10084_10083_10618_10630_10307_5711220_5722320_10313_10059_10534_100031_10103_10627_10626_10624_10623_10622_10621_10620_10142,searchweb201603_2,ppcSwitch_5_ppcChannel&algo_expid=875aa997-05fe-4eda-9d76-0aaefcaeff83-7&algo_pvid=875aa997-05fe-4eda-9d76-0aaefcaeff83&priceBeautifyAB=0

I have no experience with either board, so I don't know if either would be desirable.

The pinout of the TMC2130 is different than the A4988 driver currently used in my Woodpecker. However, I could perhaps make an adapter board to re-route the pins so as to be compatible. In that case, maybe I could plug them into my Woodpecker board. A video by Sanladerer seems to imply that might actually work:
https://www.youtube.com/watch?v=sPvTB3irCxQ

Note: from what I've read, the v1.1 TMC2130 modules are much better for adapting than the v1.0 modules.