Milling PCB's

[Cifrocco]

Does anyone have experience or suggestions regarding the milling of PCB's. This of course is an alternative to etching them. I found a nice Sherline CNC mill which can do just about anything, but uses g-code to drive the mill as is customary. To be able to mill a PCB one would need to convert Gerber code or other into g-code. I'll probably buy the mill system anyways because it's so cool, but I would love to have it mill my PCB's.

 

[Cifrocco]

Here's a photo of the mill.

 

[picbits]

From what I've read its slow, noisy and expensive on the milling bits but ........

For one off and prototyping though it seems quite a viable proposition - leave the machine running on the side, put some ear protectors on and hope the bit doesn't snap.

Here's mine before I bolted the motors on - will be good enough to mill PCBs on but at the moment I'll just be glad to get it going

**broken link removed**

 

[Carl W. Livingston]

Does anyone have experience or suggestions regarding the milling of PCB's. This of course is an alternative to etching them. I found a nice Sherline CNC mill which can do just about anything, but uses g-code to drive the mill as is customary. To be able to mill a PCB one would need to convert Gerber code or other into g-code. I'll probably buy the mill system anyways because it's so cool, but I would love to have it mill my PCB's.

Hi!

I own a Sherline 2000. I ordered the mill with the stepper motor adapters, but no control. I ordered the stepper motors from Automation Direct because, they are bipolar, whereas, the Sherline stepper motors are unipolar. I then built a control using Gecko stepper motor drives and a 5 ampere 24 VDC switching power supply. I laid out a DB25 LPT adapter PCB with screw style terminal strips to interconnect the gecko drives. I had a spare PC and used the evaluation version of Mach3 to operate the mill.

Until recently, I used a PCB layout program called HiWire II. This is a 25 year old DOS program that, I've had for nearly as long.

About 5 years ago, I purchased a MAX-NC5 and, at that time I wrote two script files that allowed me to extract the drilling and milling coordinates from the HiWire II PCB layout. But, I wasn't really happy with the software that MAX-NC provided and hence, my evaluation of Mach3.

Recently, I bought a license for Mach 3 and also a professional version of the CadSoft Eagle PCB software. That left me sort of lame for drilling and milling Eagle PCBs. I have written a script file to extract drill coordinates from Eagle but not routing, as yet.

At about the same time that I purchases the Mach3 license, I discovered PCB-G-code. This is a program that will allow you to drill, mechanically etch and route double sided PCBs. PCB-G-code is located at: https://groups.yahoo.com/search?query=pcb-gcode

I haven't actually mechanically etched a PCB yet as, I don't have any milling bits that are capable of doing the job. But, I have drilled and routed several PCBs using PCB data that PCB-G-code extracted from Eagle and, I was pleased with the results.

I hope this helps a little bit and, I hope the little excursion about my machines wasn't too boring.

Thanks!

 

[3v0]

PCB-GCODE is well supported for a free tool. The author is active in the support group.

I use a MAX_NC10 to drill boards then I do toner transfer to etch them.

 

[Carl W. Livingston]

PCB-GCODE is well supported for a free tool. The author is active in the support group.

I use a MAX_NC10 to drill boards then I do toner transfer to etch them.

Yeah! I use the toner method, as well. I use the Pulsar paper, the Green film sealer and a modified GCB laminator. It took quite a few PCBs to get the laminator to work without jaming but, now that I'm past that, I can produce some pretty nice single sided PCBs.

3V0, do you still use the MAX-NC software or have you moved on to something a bit more flexable?

I still have a machine with the MAX-NC software on it, but it's no longer used as, I now use Mach3.

 

[Carl W. Livingston]

From what I've read its slow, noisy and expensive on the milling bits but ........

For one off and prototyping though it seems quite a viable proposition - leave the machine running on the side, put some ear protectors on and hope the bit doesn't snap.

Here's mine before I bolted the motors on - will be good enough to mill PCBs on but at the moment I'll just be glad to get it going

That's some nice woodworking!

What did you use for the leadscrews?

 

[3v0]

Yeah! I use the toner method, as well. I use the Pulsar paper, the Green film sealer and a modified GCB laminator. It took quite a few PCBs to get the laminator to work without jaming but, now that I'm past that, I can produce some pretty nice single sided PCBs.

3V0, do you still use the MAX-NC software or have you moved on to something a bit more flexable?

I still have a machine with the MAX-NC software on it, but it's no longer used as, I now use Mach3.

I teach CS and basic electronics to a few kids at the local high school. (aka robot building)

The CNC machine is in the vo-tech area. They let me use it.

We only have the MAX-NC software on the PC that drives the CNC machine. We have turbo cad and another cad tool called solidcad on the design workstations. We were looking at getting solidcam which takes solidcad output and generates gcode to drive a milling machine. At least that is what I got talking with the sales rep.

There is some sort of vo-tech push going on where several private companies and NASA have banded together to get CAD CAM into high schools. The name escapes me. It looks like we may go with that program. I do not know what software or hardware that will use/require. Our school is on the small side so funding can be difficult.

I would like to get into milling metal parts but have yet to make the time to do so. Not much interest in milling PCBs. The toner transfer chemical etching is working well.

 

[Sceadwian]

Did anyone ever mention wood is bad for CNC machines? The thermal and humidity expansion models are horrific for real world applications.

 

[Carl W. Livingston]

Did anyone ever mention wood is bad for CNC machines? The thermal and humidity expansion models are horrific for real world applications.

I've seen quite a few machines made out of wood, many were made out of particle board. I can't say how the particle board stood up over the years but, I suspect that a machine made out of solid wood, and with the proper finish, would do quite well.

I've wanted to make a machine out of UHMW or Delron, or a combination of both. Strong stuff, Delron is.

I made a test axis out of PCB material soldered together. It used 5/16" all-thread for the lead screw. It too, showed promise but, I opted for the MAX-NC, at decision time.

I'm quite happy with the Sherline 2000. I'll be happy with the MAX-NC 5 too, once I get larger motors and a new control mounted to it.

The goal was to use the MAX-NC to drill & rout PCB and use the Sherline 2000for making small parts.

I did mill the front & rear panels of the control for the Sherline 2000 control. I even engraved the lettering and filled each letter with different color paint. For a first attempt, those panels came out a lot better then expected.

But back to the wood... If the wood has a proper finish and is adequately protected, it (the wood) will make a fine base for a small table-top machine. And in the case of the wood based machine shown here, it appears to be excellent craftsmanship and a fine work of art!!!

 

[3v0]

Natural wood expands across the grain much more so the along it.

Particle board does not have this problem so it is actualy a better choice then natural wood. But it does need to be sealed properly.

 

[Carl W. Livingston]

Natural wood expands across the grain much more so the along it.

Particle board does not have this problem so it is actualy a better choice then natural wood.

Good point!

 

[Speakerguy]

Sheet materials are dimensionally stable. Medium Density Fiberboard and 13 ply Baltic Birch plywood would be my choices in terms of quality.

That's what we use in speakers anyway.

 

[picbits]

That's some nice woodworking!

What did you use for the leadscrews?

Machine is made out of 18mm MDF

Leadscrews for the moment are 10mm stainless "allthread" or studding for us UK residents.

Drives are approx 180 Oz/in bipolar motors and the whole lot has linear rail and linear pillow blocks.

The woodworking I wont take full credit for. I planned the whole lot out on a graphics package and took the plans with all the cuts down to my local DIY store (B&Q) where there is a chap who is a genius on the big sheet saw - he can normally get to within half a mm accuracy (better than I could do with the tools in my garage at the moment).

Wood including cutting was £20
Bearings were around £180
Motors were £20
SS allthread was around £15
Nuts, bolts, washers etc £15
Motor couplings £40 (I have a few spare)
Motor drive electronics - well still working on them but will be under £50 for a PWM controlled variable current drive

All I really need it for initially is PCB drilling. As long as its more accurate than doing it by eye I'll be happy. It will save a lot of time on some of the stuff I build. Being able to route out multiple boards will be nice as well and from the power I've seen this machine push out (it can lift itself/50Kg easily) it should be up to the job.

 

[picbits]

Heres my wood cutter "Doug"

**broken link removed**

Complete writeup for the project here (needs updating)

https://www.cnczone.com/forums/showthread.php?t=37790

 

[mvs sarma]

Hi Picbits,

Picture is better than thousand words, and I am admired by the amont of skill and work involved in Making the zigs. Congrats you you

 

[Sceadwian]

Particle board is probably best, the resin they use somewhat insulates it from the woods worst quality shrinking and expansion with changes in humidity. I'd seal the hell out of it after bakeing it in an oven to dry it out though.