Having isues with Masso posts

[shirkbw]

For some reason my gcode post for a simple 2d contour opperation to machine a step in my part 0.5 mm deep is creating a two pass operation, in the first pass the mill is commanded to machine air at the surface of the part Z relative to the setpoint of model top being 0.  The second pass it plunges to 0.5 mm depth and completes the part.  i can see if this was two steps (say -0.25 mm the first pass and 0.5 mm the second) but not what is happening.  My mill is a Sherline 5400 so 0.25 mm depths of cut would be reasonable.  What might I check in my setup to correct this issue?

[brad_francola]

Hi.  Are you able to share your file?

[shirkbw]

(JULY STEP ATTEMPT)
(T1 D=2.377 CR=0. - ZMIN=-0.5 - FLAT END MILL)
N10 G90 G94 G17
N15 G21

(2D CONTOUR2)
N20 M5
(N25 T1 M6)
N30 S2400 M3
N35 G54
N40 G0 X14.598 Y-0.238
N45 Z26. (at 26mm for tool clearance)
N50 Z6. (reduced to standof height of 6 mm)
N55 G1 Z2. F51. (now plunging to 2 mm above surface)
N60 Z0.238 (why is this not into the part it is still above)
N65 G18 G2 X14.836 Z0. I0.238 K0. F120. (k is still at surface of part)
N70 G1 X15.074
N75 G17 G3 X15.311 Y0. I0. J0.238
N80 X-15.311 I-15.311 J0.
N85 X15.311 I15.311 J0.
N90 X15.074 Y0.238 I-0.238 J0.
N95 G1 X14.836
N100 G18 G3 X14.598 Z0.238 I0. K0.238 (again above part)
N105 G0 Z26. (back to clearance height)
N110 Y-0.238
N115 Z6. (down to standoff height)
N120 G1 Z2. F51. (still 2 mm above)
N125 Z-0.262 (infally down into material, but only 1/2 proper depth)
N130 G2 X14.836 Z-0.5 I0.238 K0. F120. (now finally into part at proper depth)
N135 G1 X15.074
N140 G17 G3 X15.311 Y0. I0. J0.238
N145 X-15.311 I-15.311 J0.
N150 X15.311 I15.311 J0.
N155 X15.074 Y0.238 I-0.238 J0.
N160 G1 X14.836
N165 G18 G3 X14.598 Z-0.262 I0. K0.238 (not sure why the move to 1/2 depth)
N170 G0 Z26.
N175 G17

N180 M30

[brad_francola]

Thanks.  Can you share your *.f3d file?  That would be best.  

[shirkbw]

https://a360.co/3NW1IBD

[brad_francola]

Hi.  Your NC program is making two passes because your toolpath has two chains selected (one of which is at the top of the part which is Z-zero in your setup).

bradfrancola_0-1688330882896.pngbradfrancola_1-1688330925665.png

It may be better for your to only select the contour at the bottom of your feature and use Multiple Depths to control how many cuts you want to take.

bradfrancola_2-1688331058762.png

[shirkbw · Accepted solution]

Thank you so much, this explains a lot, not why I was getting it to mill to china on an earlier attempt but I think like this is was a loose nut in front of the keyboard.