Need PCB Milling Settings

scott216
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Re: Need PCB Milling Settings

Post by scott216 » Mon Jun 02, 2014 11:30 am

zerblatt007 wrote:So 0.3mm is the usable dimension? 0.4mm is to much?
Do you drill the holes with the same bit?
0.4mm would probably work just as well, but it depends on the pad spacing and spacing between traces. I don't use the same bit for drilling holes. I actually use a drill. I got a set of PCB drills from Inventables. I've been using the 1mm drill, but that's a bit big. I'm going to use something a little smaller on my next board.
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GusPS
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Re: Need PCB Milling Settings

Post by GusPS » Thu Jun 05, 2014 7:10 pm

Thank you for sharing your work.

scott216
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Re: Need PCB Milling Settings

Post by scott216 » Thu Jan 08, 2015 7:51 pm

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. Previoulsy 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"
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MeanderBolt
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Re: Need PCB Milling Settings

Post by MeanderBolt » Sat Jan 10, 2015 7:40 pm

Hey Scott, what "G-Code Style" do you choose on your PCB-GCode? I am looking at all these options and my brain just returns (???). I am just about to run my first board. I am going to also be trying the auto leveling in ChiliPeppr. BTW, thanks for all these settings. I will add this to the global pcb thread I started last week.

I just have one pad I have to figure out. It is all smd and I have one pad I need to get connected to ground, but it is mostly surrounded. I could use a jumper, but I am still trying to solve it (without having to run a ridiculous line all the way around the thing. Heh.
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scott216
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Re: Need PCB Milling Settings

Post by scott216 » Sat Jan 10, 2015 8:23 pm

MeanderBolt wrote:Hey Scott, what "G-Code Style" do you choose on your PCB-GCode? I am looking at all these options and my brain just returns (???). I am just about to run my first board. I am going to also be trying the auto leveling in ChiliPeppr. BTW, thanks for all these settings. I will add this to the global pcb thread I started last week.

I just have one pad I have to figure out. It is all smd and I have one pad I need to get connected to ground, but it is mostly surrounded. I could use a jumper, but I am still trying to solve it (without having to run a ridiculous line all the way around the thing. Heh.
I made my own G-Code style (shapeoko.pp) file. It belongs in \pcb-gcode\profiles\ directory

If I'm making a single sided PCB and want to avoid a long trace, in Eagle I'll make a trace on the top, but in reality trace will be a jumper wire. When I do this I like to make sure my top trace is a single straight wire. Also, I make the vias for this trace bigger then the default, so it's more like a normal solder pad. To make the via bigger click on the info tool, then click on the via to see it's settings. I like to use round shape, and I manually set the drill diameter and OD. I usually make the drill about 0.039, but this will actually just be whatever drill you use in the shapeoko. I make the OD about 0.076.

I also made my own drill file (shapeoko.drl). What this does is tell pcb-gcode to combine a range of drill sizes into one size. If you don't, then your shapeoko will go through a drill change move for every drill size. A drill change move is where the shapeoko goes to 0,0 position so you can change the drill. This is fine if you really want to change the drill, but if I have one hole that 0.039 and another that's 0.041, I'm going to use the same drill. I do want mounting holes to be separate because they are a much bigger drill. Here's how I have my drill file setup:

tool drill_size minimum maximum length
T01 0.0240in 0.0000in 0.0240in 1.5in
T02 0.0620in 0.0241in 0.0999in 1.5in
T03 0.1250in 0.1000in 0.1500in 1.5in

The drill file belongs in \pcb-gcode\settings\ directory

There's another file I modified that also goes in \settings\ directory. It's called user-gcode.h. The lets me customize some of the g-code output. The main thing I do is use it to set my work coordinates. I have my machine setup so work coordinates G55 are used for any bottom etching, milling, etc. And work coordinate G56 is used for the top. In my setup I register the PCB on the left-front edges (from shapeoko's perspective). When I flip it over to do the other side, it still registers the left front sides, but from the PCBs point of view, the edge that was on the left is now on the right. So basically I have to shift the work coordinate system the width of the PCB. I don't know if I'm explaining this very well. Work coordinates can be a bit confusing at first, but once you get the hang of them, they are a big benefit

Another feature I HIGHLY recommend is get a touch plate to automatically set your z-height above the PCB. This has saved me a lot of time fiddling with the height.

To use the touch plate, I jog so the bit is close, then issue this command:
G20 G38.2 Z-2 F0.118
This will make the z-axis feed down slowly until it touches the plate. Then to zero the z-axis, I issue this command
G20 G92 Z0.7874
My touch plate is 0.7875 inches high (20 mm)
Then I manually jog the z-axis up a bit and remove the touch plate.

I hope this helps. I zipped all 3 files mentioned and attached them
Attachments
Scotts shapeoko files.zip
ShapeOko user config files
(3.6 KiB) Downloaded 169 times
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MeanderBolt
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Re: Need PCB Milling Settings

Post by MeanderBolt » Sat Jan 10, 2015 9:42 pm

Wow. Great info!!!
The pcb I am working on right now is all smd, so it is all top layer. I can't do any holes or vias on this board as it will be against the machine and I am trying to avoid any shorts. (end stops).

A few questions...
If I am milling a pcb, wouldn't I just use the pcb as the touch plate? This way there is no need to translate. More, if I am going to use the auto leveling, it has to be between the pcb and the mill.

Repeating what I think you are saying... Am I correct.
So, in your drill file is it saying...
T01 0.0240in 0.0000in 0.0240in 1.5in
If it is between 0.0000in and 0.0240in use T01 0.0240in drill? Is so, this is very cool.

So... these are your drill sizes? Do you use drills for your drilling, or do you use mills? I have seen both used.
You mention .0240, I have seen .0247 and .0236 I suppose that if I settle for something in this range I should be good? I guess at some point you are splitting hairs (heh, literally).

Again this is my first pcb with the machine. Hopefully this will make toner a thing of the past. From those who have made this work, it sounds like it is.

I will try to get these into my Eagle asap.
Shapeoko 2 # 3569 - DW660
Current tool chain > Draftsight > CamBam > ChiliPeppr
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scott216
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Re: Need PCB Milling Settings

Post by scott216 » Sat Jan 10, 2015 9:56 pm

MeanderBolt wrote:Wow. Great info!!!
A few questions...
If I am milling a pcb, wouldn't I just use the pcb as the touch plate? This way there is no need to translate. More, if I am going to use the auto leveling, it has to be between the pcb and the mill.
Yes, that should work also but the problem I had when I tried that is my hands also touched the copper on the PCB as I was holding a wire to it and that cause some problems. The shapeoko thought the bit touched the PCB when i touched it.
Repeating what I think you are saying... Am I correct.
So, in your drill file is it saying...
T01 0.0240in 0.0000in 0.0240in 1.5in
If it is between 0.0000in and 0.0240in use T01 0.0240in drill? Is so, this is very cool.
That's correct
So... these are your drill sizes? Do you use drills for your drilling, or do you use mills? I have seen both used.
You mention .0240, I have seen .0247 and .0236 I suppose that if I settle for something in this range I should be good? I guess at some point you are splitting hairs (heh, literally).
Unless I have an unusual part, I only use two drill sizes (I don't use mills). For through hole components I use a 1mm drill, for mounting holes I use a 1/8" drill with a 60 degree point.
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MeanderBolt
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Re: Need PCB Milling Settings

Post by MeanderBolt » Sun Jan 11, 2015 12:43 am

Thanks Scott!!!
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MeanderBolt
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Re: Need PCB Milling Settings

Post by MeanderBolt » Sun Jan 11, 2015 3:00 pm

So... Myeah... I got your files in with no problems. I am working in mm so I got all that changed. I spent far too long looking for any reason that this would not work (in Eagle). So, it came time to try it out. I went into ChiliPeppr and tried to run the auto leveler. But I started to see some weirdness. It was not probing all the way to the board, it was stopping a fraction of a mm above. I thought my eyes were going buggy, so I grabbed a X10 magnifier and looked and sure enough, it was getting tripped in mid air. I even put a paper between the mill and the pcb and was able to easily move it around with plenty of room to spare. I am thinking I have a noise problem. This is probably similar to what you were mentioning about when you touched the pcb, you were tripping it.

I had some other wackiness some time back which I suspected noise, so I may go on a noise hunt. It might be some floating ground issues someone posted about being that the spindle ground and the Arduino ground aren't connected and argue. My brain is vaguely remembering this so, I might be telling the story wrong. But that is todays adventure.
Shapeoko 2 # 3569 - DW660
Current tool chain > Draftsight > CamBam > ChiliPeppr
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scott216
Posts: 228
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Location: New Jersey

Re: Need PCB Milling Settings

Post by scott216 » Tue Jun 30, 2015 10:51 am

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 v2 with DW660
GRBL v0.9i
Location: New Jersey

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