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Trouble with my PCB attempts. #eagle #pcbgcode #etch

tsames2008@...
 

I thought I was getting an understanding of pcbgcode.  Attached is a photo of my closest attempt yesterday at the bottom of the copper.  I decreased the sizes so that the traces should have been cut correctly.  But when I attempted the next etching this morning, the software seems to work backs from the tracings and mills into instead of outward from the trace.  Is this a bug?  I'm using chilipeppr to send the gcode to my 3018 CNC.  It seems accurate, the spacing for the .1 pad holes check out spot on the money.  Results after little light sanding using a 10 degree V bit look good but the I can not get it to create a usable etching on the copper due to the cutting, or more accurately gutting, of my trances.being destroyed.  It looks correct in the 3D view but the results are frustrating.

Any suggestions would be welcomed.


Art Eckstein
 

If I had to guess, I think you might have your tool diameter set to small.
I haven't ever used a 10° cutter, but all the ones I have used do not come to an exact point. 

I found the best thing to do was to "calibrate" the tool diameter usning the method developed by Poul-Henning Kamp at < http://phk.freebsd.dk/CncPcb/calibrate.html>

I found significant differences between cutters that were supposidly the same. 

HTH

Country Bubba


At 8/9/2018 05:55 PM, tsames2008 via Groups.Io wrote:

I thought I was getting an understanding of pcbgcode.  Attached is a photo of my closest attempt yesterday at the bottom of the copper.  I decreased the sizes so that the traces should have been cut correctly.  But when I attempted the next etching this morning, the software seems to work backs from the tracings and mills into instead of outward from the trace.  Is this a bug?  I'm using chilipeppr to send the gcode to my 3018 CNC.  It seems accurate, the spacing for the .1 pad holes check out spot on the money.  Results after little light sanding using a 10 degree V bit look good but the I can not get it to create a usable etching on the copper due to the cutting, or more accurately gutting, of my trances.being destroyed.  It looks correct in the 3D view but the results are frustrating.

Any suggestions would be welcomed.




Attachments:

Brett Pound
 

non-flat PCB material. How are you holding the stock down? 

Unfortunately, the tolerances are so small on this stuff, that small deviations can ruin a board. Cheap plating, uneven FR4 to start with, or poor adhesion to the baseboard can all make a good board go bad.

Honestly, using autoleveller helps, but it's still a tolerances game...

peterg1000
 

Using Eagle (rev7, 8 and 9) and pcbgcode I am able to reliably mill/"etch" boards with 0.01" tracks and gaps.

For what it is worth, my setup is as follows:-

Stepcraft CNC 420 router  with UC100 motion controller and UCCNC control software on Windows PC.

Small (6" x 8") vacuum table milled flat in-situ on router.

"Chinese" vane type vacuum pump

Home made touch probe interfacing to UCCNC software. Z0 set to better than 0.001" of copper.

Low cost 30 degree milling cutters ( 0.008" (0.2mm) cutting "point") - readily available on Ebay.

Attached is a picture of an SMD board recently made using the above.

Peter

tsames2008@...
 

I'm using the autoleveler for Grbl control units built into Chilipeppr with wonderful results.  The second etching (the etching on top) was when I tried to reduce the size of the min/max and step size.  I didn't alter the drill size, so I thought, it would allow it to cut between the pads properly without reducing the milling of the traces.

 

The traces is what I'm having trouble preserving.  I really don't understand why, if I don't change the drill bit size, it get's into the traces.

tsames2008@...
 

That looks beautiful.  What settings are you using for your min/max and step size?  Also, when you use a 30 degree V bit, what size do you enter for your drill bit size.  Also, what unit size are you using (inches, mm, or mils)?

tsames2008@...
 

Okay, no one actually gave the settings that could have saved me days so I will post what I used to save someone else time and frustration.

while using a .1 mm 30 degree V bit, I used:

Single pass

Isolation Minimum 1.35 mils
(not used) Maximum 6 mils
(not used) Step 1.5 mils

Z Down -4 mils

I used Z Probe for every etching.

tsames2008@...
 

Alright, after almost a month, finally created my first layout using etching, drilling and milling (to cut out the boar).  Now this is my test run to see if everything lines up.  Now that it does, I will increase the depth to fully cut the drill holes out and cut the board out.

 

Brett Pound
 

your drill sizes are too big, do you have a smaller drill ?  those header pads will struggle to hold together and you'll be relying on solder a lot

John Johnson
 

Nice looking board! I agree with the hole-size concern.
Looks like you have a sliver (see the arrow), so you might want to try using multiple passes and/or going over the board with an Xacto knife.

On 6 Sep 2018, at 13:08, tsames2008 via Groups.Io wrote:

Alright, after almost a month, finally created my first layout using etching, drilling and milling (to cut out the boar).  Now this is my test run to see if everything lines up.  Now that it does, I will increase the depth to fully cut the drill holes out and cut the board out.

 

John Johnson
 

And the arrow…

On 7 Sep 2018, at 7:54, John Johnson wrote:

Nice looking board! I agree with the hole-size concern.
Looks like you have a sliver (see the arrow), so you might want to try using multiple passes and/or going over the board with an Xacto knife.

On 6 Sep 2018, at 13:08, tsames2008 via Groups.Io wrote:

Alright, after almost a month, finally created my first layout using etching, drilling and milling (to cut out the boar).  Now this is my test run to see if everything lines up.  Now that it does, I will increase the depth to fully cut the drill holes out and cut the board out.