Need PCB Milling Settings

jkanzaki
Posts: 166
Joined: Sat May 05, 2012 3:00 am

Re: Need PCB Milling Settings

Post by jkanzaki » Wed Nov 25, 2015 3:21 am

Hey Scott,

I have a couple question for you, I am new to pcb milling. I hope you can share with me your experience.

1)how do you derive at your feedrate? Is there a calculator you use or link you use?
2) Is there a difference between using 0.01 vs 0.0039 Precise Bits EM2E8 EM3E8 Etching Bits in terms of quality?
3) If I use the 0.0039, do you think it will effect the isolation performance of the board because the trace are so small?
4)Do you use auto leveling in your workflow?

Cheers
Henry
scott216 wrote:
scott216 wrote:By far the best bit I've used for making PCBs is the PreciseBits.com PCB Traces-isolation Bits EM3E8-0100-25V. You can get the same bit from soigeneris.com, P/N C5 - PB-EM3E8-0100-25V

I've made over a dozen PCBs and haven't broken a bit yet. Previously with a 0.0118" 2-flute micro carbide mill like this one I'd be lucky to get 3 boards. And that's at 5 IPM. With the Isolation bit, I'm going 18 IPM (@ 30k RPM) and I might be able to go a lot higher. One guy posted he's going 40 IPM a @ 40k RPM. And the edge finish with these bits is great, I don't need to sand the board. I do use a lot of WE40 and have yet to try doing it dry.

I use Cadsoft Eagle with pcb-gcode script to generate the gcode. My bit diameter is set to 0.015", which is a little larger then the actual bit, but I do have some run-out in my spindle. Some of my other pcb-gcode setting are:

Isolation settings:
Singly Pass - unchecked
Min: 0.0"
Max: 0.0150"
Step: 0.0075"

Z-depth
etch: 0.005"
mill: 0.075"
drill: 0.090"
text: 0.005"
I'm really happy with these tapered isolation bits, I'm haven't broken one yet! I've got the speed up to 26 IPM with my Dewalt DW660 going 30,000 RPM. I'm running dry without WD40 and the results are pretty good. I do clean up the edges with a little 400 grit wet-dry sandpaper and mineral spirits.
Shapeoko 1 - dissassemble
Shapeoko 2 - 1 x 1m expansion TinyG, superPid, Dw660, Aluminum extrusion bed, Nema 23, acme, Z axis upgrade, Dual Y
Shapeoko 3 - 0051 Stock Dw611, SuperPid, limit switch, 9mm belt

WillAdams
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Joined: Mon Apr 09, 2012 6:11 pm
Location: Pennsylvania --- south of the Turnpike, East of US-15
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Re: Need PCB Milling Settings

Post by WillAdams » Wed Nov 25, 2015 11:36 am

Links to calculators at the top of this page: http://www.shapeoko.com/wiki/index.php/Materials#PCB and shared feed and speeds farther down.
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
Nomad 883 Pro #596 (bamboo)

scott216
Posts: 228
Joined: Thu Oct 10, 2013 12:35 pm
Location: New Jersey

Re: Need PCB Milling Settings

Post by scott216 » Wed Nov 25, 2015 1:50 pm

jkanzaki wrote:Hey Scott,

I have a couple question for you, I am new to pcb milling. I hope you can share with me your experience.

1)how do you derive at your feedrate? Is there a calculator you use or link you use?
2) Is there a difference between using 0.01 vs 0.0039 Precise Bits EM2E8 EM3E8 Etching Bits in terms of quality?
3) If I use the 0.0039, do you think it will effect the isolation performance of the board because the trace are so small?
4)Do you use auto leveling in your workflow?

Cheers
Henry
Henry
1) I used trial and error for my feedrates. Before I starting using the EM3E8 bits, I could only got about 6 IPM. When I switched to EM3E8 I slowly increased the IPM each time I made a board, I tried 8, then the next board 10 and so on.
2) I don't know how a small bit will affect the quality. The smaller the bit, the more impact run-out will have, hopefully your spindle has very little. Also, with smaller diameter, you should increase your RPMs. I've only used the 0.01" bit
3) I'm not sure about your question. If you're doing a single pass isolation, are you concerned that your isolation distance is so small it could be a problem? If that's your question, then any little burr or chips could cause a short. I'd go over your board with a magnifying loop to check for this. I use pcb-gcode Eagle script and with that you can take multiple isolation passes to increase your isolation distance. I normally will do this. It takes a lot longer to mill the board, but that's okay for me.
4) I don't use autoleveling, but I want to start. I want to give it a try with the Chilipeppr
Shapeoko v2 with DW660
GRBL v0.9i
Location: New Jersey

jkanzaki
Posts: 166
Joined: Sat May 05, 2012 3:00 am

Re: Need PCB Milling Settings

Post by jkanzaki » Tue Dec 08, 2015 7:21 am

So I did experienced with Drill mill, 30, 45, 60 and 0.01 vs 0.0039 Precise Bits EM2E8 EM3E8 earlier today.
I'll post my finding here later.

Also does anyone here has recommendation on what bit to use for cutting out pcb boards?
I have 1mm single flute
http://www.ebay.com/itm/1-00mm-0394-sin ... 2321b16795

as well as 1mm double flute
http://www.ebay.ca/itm/1-00mm-0394-2-FL ... 1150305141

can I use those for pcb milling?
what is the feedrate for doing board cut out ,anyone know?

thanks
Shapeoko 1 - dissassemble
Shapeoko 2 - 1 x 1m expansion TinyG, superPid, Dw660, Aluminum extrusion bed, Nema 23, acme, Z axis upgrade, Dual Y
Shapeoko 3 - 0051 Stock Dw611, SuperPid, limit switch, 9mm belt

WillAdams
Posts: 8528
Joined: Mon Apr 09, 2012 6:11 pm
Location: Pennsylvania --- south of the Turnpike, East of US-15
Contact:

Re: Need PCB Milling Settings

Post by WillAdams » Tue Dec 08, 2015 12:11 pm

What we have thus far is on the wiki: http://www.shapeoko.com/wiki/index.php/ ... lling_PCBs

I believe there are some PCBS-specific recommendations at: http://www.shapeoko.com/wiki/index.php/ ... mendations

If we’ve missed anything, please let us know. Looking forward to your posting your results!
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
Nomad 883 Pro #596 (bamboo)

scott216
Posts: 228
Joined: Thu Oct 10, 2013 12:35 pm
Location: New Jersey

Re: Need PCB Milling Settings

Post by scott216 » Tue Dec 08, 2015 4:05 pm

jkanzaki wrote: Also does anyone here has recommendation on what bit to use for cutting out pcb boards?
I use a 1.90 mm from Precise Bits, P/N #RCC08-0748-032F
http://www.precisebits.com/products/car ... router.asp
Shapeoko v2 with DW660
GRBL v0.9i
Location: New Jersey

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