Comments on: DIYLILCNC: do-it-yourself CNC mill

By: ewertz

ewertz — Mon, 31 May 2010 01:43:54 +0000

There’s probably more than one product out there that does this, but LPKF does sell a product for this. I think that it’s a (one-part, I’m assuming) conductive epoxy that you squeegee through the holes, bake it and then drill through it.

You might want to check it (and similar products) out. That’s the general process though.

By: Fili

Fili — Thu, 27 May 2010 07:08:50 +0000

Well, I have a Sable CNC (not the small 2015, a larger version 3000-something) and it cuts very fine traces. Also using a small probing g-code I can adjust the height of the g-code so it doesn’t matter if the board is level or not. It’s true, it takes longer than the toner transfer but at least it’s working every single time and I don’t have to work with chemicals that I have to dispose of later. So instead of working one hour on a board, trying to get the sides aligned, drilling the holes by hand, etc, I just go to the machine, put the board, run the drilling code, 5 minutes later I change the tool, run the isolation code for one side, watch tv for 40-60 minutes, go back, flip the board during the commercial break, watch tv for another hour, and done, i have my board ready.
Now I just have to find a way to do through-hole plating…

By: Dan

Dan — Thu, 18 Mar 2010 05:01:54 +0000

Hey guys, I am looking to possibly build a CNC machine to cut some 14gauge steel I have. Do you guys know if a set up like this is capable of cutting material like this, and how accurate it would be compared to something like plasma or lazer cutting?
Thanks for any help in advance

By: ericwertz

ericwertz — Tue, 24 Nov 2009 08:52:19 +0000

Thanks for the leads, I’ll definitely be checking them out!

By: 10bulls

10bulls — Thu, 19 Nov 2009 10:10:47 +0000

@ericwertz: I’ve used these…
http://www.cnc-plus.de/index.php?cat=c111_V-groove-router.html

There is also a guy in the states:
http://www.drewtronics.net/
$6.50ea !!! – I’ve not used his, but I know he has a good reputation on the pcb-gcode forums.

Yeah, if someone was selling me a cutter for $18, I’d be a bit wary if they say it will only do 30 meters – bit like buying a porsche and them saying ‘You’ll need to buy a new one after 100k miles … or it’ll explode!!!’ ;-)

If your cuts start to get a little fuzzy, a few wipes with a diamond hone may help to give your cutters an edge.

Also, having a good spindle with no runout is a must.

Good luck!

By: ericwertz

ericwertz — Wed, 18 Nov 2009 12:40:02 +0000

The bits I’m using are “100% carbide”. I’m assuming tungsten carbide. Probably not calcium carbide… lol.

By: svofski

svofski — Wed, 18 Nov 2009 10:01:29 +0000

@ericwertz: probably you need to look for tungsten carbide bits. They’re the only kind appropriate for PCB substrate.

By: ericwertz

ericwertz — Wed, 18 Nov 2009 09:28:53 +0000

@10bulls
I’d love a name/source/whatever for your bits. After this first project, I’ve been wanting to find some acceptable non-manufacturer bits. The manufacturer’s cutting bit has a suggested tool life that appears to yield 30 meters of use at $18/bit. I probably went through about 3.5 bits for 80 sq.in x 2 sides (150 sqin or so total).
Drilling, fill removal and routing (180in) probably doubles that cost.

RPM’s 30K if I remember correctly.

By: 10bulls

10bulls — Tue, 17 Nov 2009 09:31:12 +0000

@ericwertz
Yes, boards are smallish : 3.75sq.in.
Cutters last me ages…I use 60 or 45 degree solid carbides which cost me about 7EUR ($10). I tend to snap them before I wear them out (doh!).
What rpm are you using? $55-$60 of cutters sounds a lot! I try to just break through the copper so I don’t cut much fiber glass which will wear the cutters quick.
Yes, I only do isolation (up to ~19mil) – flood fills take too long and aren’t really needed for the prototypes I do.

By: ericwertz

ericwertz — Tue, 17 Nov 2009 07:49:01 +0000

@10bulls: how big were your boards? I’m guessing about 2.5 sq.in.? How many cutters and endmill bits did you go through? 50 sq.in. double-sided on our mill is probably $80 worth of bits if you end-mill out the guts, and probably $55-60 if you isolate only ~16mils.

Can’t agree more about missing PTHs. Tin coating is nice too, but at least that’s doable. Plus, if it’s only for prototypes, you’re throwing them away anyways.

By: 10bulls

10bulls — Mon, 16 Nov 2009 22:58:27 +0000

I recently isolation routed a small run of 20 boards for a robotics class. They were double sided and contain a mix of SMD and through hole.

It really does work great and each board was taking ~20mins on a pretty slow machine for both sides including 3 drill sizes. Done a lot of etched boards too…etching sucks! CNC rocks!

Biggest drag with home made boards is no plate-through but that is problem with CNC or etching.

A bit more (gettting rather old) info here…
http://www.brusselsprout.org/PCB-Routing/

By: Laminar

Laminar — Mon, 16 Nov 2009 14:43:57 +0000

How about replacing the Dremel tool with a plasma torch and having a CNC plasma cutter?

By: svofski

svofski — Mon, 16 Nov 2009 10:57:25 +0000

@Konstantin: Thanks for posting this. I think that your mill is pretty clever.

By: Konstantin

Konstantin — Mon, 16 Nov 2009 07:21:20 +0000

@svofski
I havent made a post about the machine, since its not a big deal I guess. I have some photos of it here http://s169.photobucket.com/albums/u222/konstantin_neo/Cnc%20Engraver/

If your mill has the same Z level on the whole pcb then you can mill just the surface of the copper off the blank, I can do that on my mill, it takes a while to set up but it is doable. While milling only the copper away you mill as less as possible and the overall quality is very good.

Higher cost brand mills face same problems too. The spindle selection is paramount if you want as low run-out as possible, again I go for Proxxon IB/E.
In my mill I had to make a custom 1/8 bit holder using a spindle from an OOOOOld hard drive (it was of 129MB with bad sector count printed on the label and it hosted 8 plates) and turning a shaft from round stock to accept Dremel attachments.

Dremel collets are made from aluminum and they are far from good quality (for pcb milling that is).
One thing very gratifying is to have the pcb drilled perfectly, I just swap the bits when the cnc program (mach3) asks for it.
Prototyping this way is fast this way, for production of a well designed board I’d say go for TT or outsource.

By: Adam

Adam — Mon, 16 Nov 2009 04:43:36 +0000

Wouldn’t it be simpler to control the thing with the RepRap electronics? It’s cheaper (only $128 for the boards, not including steppers), and you can use Skeinforge/ ReplicatorG to convert your model files to toolpaths. Seems like it’d be easier.

-Adam