Topics

end mills for drilling #drill

Dave Zahn
 

Hello. I love the pcbgcode add on but I can't use it. I have an ATC on my stepcraft 420 machine which is what I use for making boards but it only holds 5 bits and many of the parts I use have several different sized holes. What I have been doing to work around this is exporting the DXF file and importing it into VCarve. Then I use a 1/32 end mill and do a profile cut inside each hole.
I'm not much of a coder but I would think that this would be fairly easy enough to add and it would save having to have multiple drills in a rack as well as being able to cut even large holes for mounting etc.
Any thoughts?

John Johnson
 

Hi Dave,

Can you post g-code, say to cut a 1/8" hole using a 1/32" endmill? It might be possible to use your code as a template, along with a few tweaks to pcbgcode.

Regards, JJ

John Johnson
 

Better yet, I’ve created an issue on GitHub, and will post your message there. Maybe someone will jump in :-)

Thanks, JJ

Dave Zahn
 

This is the g-code created by VCarve to cut an 1/8" hole centered at coordinates 0,0 in material that is .06" thick in 4 passes.
Top of material is Z0

( eighth test hole )
( File created: Saturday May 26 2018 - 06:22 PM)
( for Mach2/3 from Vectric )
( Material Size)
( X= 3.000, Y= 5.000, Z= 0.060)
()
(Toolpaths used in this file:)
(Profile 1)
(Tools used in this file: )
(1 = End Mill {0.0313 inches})
N100G00G20G17G90G40G49G80
N110G70G91.1
N120T1M06
N130 (Tool: End Mill {0.0313 inches})
N140G00G43Z0.8000H1
N150S12000M03
N160(Toolpath:- Profile 1)
N170()
N180G94
N190X0.0000Y0.0000F12.0
N200G00X0.0000Y0.0468Z0.2000
N210G1X0.0000Y0.0468Z-0.0150F12.0
N220G2X0.0468Y0.0000I0.0000J-0.0468
N230G2X0.0000Y-0.0468I-0.0468J0.0000
N240G2X-0.0468Y0.0000I0.0000J0.0468
N250G2X0.0000Y0.0468I0.0468J0.0000
N260G1X0.0000Y0.0468Z-0.0300
N270G2X0.0468Y0.0000I0.0000J-0.0468
N280G2X0.0000Y-0.0468I-0.0468J0.0000
N290G2X-0.0468Y0.0000I0.0000J0.0468
N300G2X0.0000Y0.0468I0.0468J0.0000
N310G1X0.0000Y0.0468Z-0.0450
N320G2X0.0468Y0.0000I0.0000J-0.0468
N330G2X0.0000Y-0.0468I-0.0468J0.0000
N340G2X-0.0468Y0.0000I0.0000J0.0468
N350G2X0.0000Y0.0468I0.0468J0.0000
N360G1X0.0000Y0.0468Z-0.0600
N370G2X0.0468Y0.0000I0.0000J-0.0468
N380G2X0.0000Y-0.0468I-0.0468J0.0000
N390G2X-0.0468Y0.0000I0.0000J0.0468
N400G2X0.0000Y0.0468I0.0468J0.0000
N410G00X0.0000Y0.0468Z0.2000
N420G00Z0.8000
N430G00X0.0000Y0.0000
N440M05
N450M30
%

It cuts in 4 passes.
Here is some explanation of the codes:
Line #N150 sets spindle speed to 12000 rpm and turns on spindle
N180 - sets the movement mode to units per minute
N190 moves to coordinate 0,0 and sets feed rate to 12
N200 sets movement to rapid (ignore feed rate) and position the bit to X0,Y0.0468 and Z0.200 ( .2" above work piece)
         This position places the bit just inside of the circle, at the 12 o'clock position. It is calculated like this:
         x is center of circle, y = center of circle + (radius - 1/2(tool diameter)) so y = 0 + (0.0625 - .5 * (0.0313)) = 0.04685 (5th decimal is truncated)
N210 sets movement to feed rate (G1) and plunges tool to -0.0150
N220 sets movement to arc movement (G2) and moves the bit to X0.0468 Y0.0000 in an arc around the center. This is where
          code gets a little funky. The center is defined as the starting position (0 , 0.0468) plus the offset values of I and J (0 , -0.0468)
          or:  center of arc = (X - I , Y - J) = ( 0 - 0 , 0.0468 + (-0.0468)) = (0 , 0).  This has the effect of cutting the top right 1/4 of the circle.
N230 Cuts the bottom right 1/4 of the circle the same way. The starting position is the end of the last arc ( X0.0468 , Y0.0000) so the offset is
          now (I-0.0468 , J0.0000)
N240 Cuts the bottom left 1/4 of the circle the same way.
N250 Cuts the top left 1/4 of the circle the same way and if all works right, you should be right back to the original starting position (0 , 0.0468)
N260 - N300 are exactly the same except at a depth of -0.0300
N310 - N350 are exactly the same except at a depth of -0.0450
N360 - N400 are exactly the same except at a depth of -0.0600
N410 switches to rapid movement mode (G00) and moves the bit to .2" above the work piece.
N420 moves the bit to .8" above the work piece
N430 moves the bit to home position (0 , 0)
N440 turns off spindle
N450 rewinds code and resets all modes


I hope this helps.
Here is a link I used to learn the G02 Arc format:
https://www.cnccookbook.com/cnc-g-code-arc-circle-g02-g03/