Machsupport Forum
G-Code, CAD, and CAM => LazyCam (Beta) => Topic started by: CDyckes on April 27, 2007, 09:47:28 AM
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Working extremely well since using the 3GHz P4 PC in the lounge (very tolerant girlfriend). Possibly biggest display yet (65" plasma) :)
(http://www.pbase.com/cdyckes/image/77819855/large.jpg)
Having a minor toolpath problem with another simple object. The top line should be straight, but the start point (top centre) is too high and adjusts to the correct height by the end of the segment.
(http://www.pbase.com/cdyckes/image/77819585/large.jpg)
Previous items with this sort of toolpath have cut correctly, the workpiece hasn't moved, and the problem is repeatable. Zip file containing the Lcam project, dxf and tap file is attached.
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One other point: I've never worked out how to use tool compensation so all drawings allow for the width of the cutter (2mmm end mill). Must learn tool size compensation one day :)
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Try this one :-
Graham.
O0001 (SPKR)
G21 G40 G80 G17
N1 (2MM SLOT DRILL)
G00 G90 G43 X129.33 Y110.529
T1 M6
Z25.
S4500 M3
G00 Z1.
G01 Z-1.5 F10.
G02 X129.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X129.33 Y110.529 R0.41
G01 Z-3. F10.
G02 X129.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X129.33 Y110.529 R0.41
G00 Z25.
X109.33 Y110.529
Z1.
G01 Z-1.5 F10.
G02 X109.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X109.33 Y110.529 R0.41
G01 Z-3. F10.
G02 X109.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X109.33 Y110.529 R0.41
G00 Z25.
X109.33 Y75.529
Z1.
G01 Z-1.5 F10.
G02 X109.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X109.33 Y75.529 R0.41
G01 Z-3. F10.
G02 X109.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X109.33 Y75.529 R0.41
G00 Z25.
X129.33 Y75.529
Z1.
G01 Z-1.5 F10.
G02 X129.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X129.33 Y75.529 R0.41
G01 Z-3. F10.
G02 X129.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X129.33 Y75.529 R0.41
G00 Z25.
X149.33 Y75.529
Z1.
G01 Z-1.5 F10.
G02 X149.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X149.33 Y75.529 R0.41
G01 Z-3. F10.
G02 X149.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X149.33 Y75.529 R0.41
G00 Z25.
X169.33 Y75.529
Z1.
G01 Z-1.5 F10.
G02 X169.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X169.33 Y75.529 R0.41
G01 Z-3. F10.
G02 X169.945 Y75.884 R0.41 F50.
Y75.174 R0.41
X169.33 Y75.529 R0.41
G00 Z25.
X169.33 Y110.529
Z1.
G01 Z-1.5 F10.
G02 X169.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X169.33 Y110.529 R0.41
G01 Z-3. F10.
G02 X169.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X169.33 Y110.529 R0.41
G00 Z25.
X149.33 Y110.529
Z1.
G01 Z-1.5 F10.
G02 X149.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X149.33 Y110.529 R0.41
G01 Z-3. F10.
G02 X149.945 Y110.884 R0.41 F50.
Y110.174 R0.41
X149.33 Y110.529 R0.41
G00 Z25.
X140.449 Y140.216
Z1.
G01 Z-1.5 F10.
X140.737 Y136.609 F50.
G02 X139.74 Y135.529 R1.
G01 X90.74
G03 X87.74 Y132.529 R3.
G01 Y53.529
G03 X90.74 Y50.529 R3.
G01 X188.74
G03 X191.74 Y53.529 R3.
G01 Y132.529
G03 X188.74 Y135.529 R3.
G01 X139.74
G02 X138.777 Y136.261 R1.
G01 X137.613 Y140.434
G00 Z25.
X140.449 Y140.216
Z-0.5
G01 Z-3. F10.
X140.737 Y136.609 F50.
G02 X139.74 Y135.529 R1.
G01 X90.74
G03 X87.74 Y132.529 R3.
G01 Y53.529
G03 X90.74 Y50.529 R3.
G01 X188.74
G03 X191.74 Y53.529 R3.
G01 Y132.529
G03 X188.74 Y135.529 R3.
G01 X139.74
G02 X138.777 Y136.261 R1.
G01 X137.613 Y140.434
G00 Z25.
M30
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Graham,
Thanks, but that doesn't seem to bear any resemblance to the original. Does it check anything in particular?
I've looked in more detail at the G-code for my job and the displays while the job is running and everything looks OK. I'd suspect a backlash problem, but a number of other similar jobs have cut without problem, including a subsequent one cutting a smaller section of the original. The error on the positioning for the start of the outside cut at top centre is +0.89mm - i.e. Mach3 has moved the table by an additional 0.89mm over and above what it says on the displays, but it sorts itself out by the time it finishes cutting the outer rectangle which is perfect other than this first segment. I think the fact that the Y co-ord sorts itself out by the time it has reached the top right hand arc on the corner eliminates the backlash possibility (plus there are no scuff marks on the material at the plunge point??
Beginning to think this is more Mach3 related than Lazycam.
Don't get me wqrong though; both are BRILLIANT products suited to beginners and experts alike!!
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Your problem looks like a Comp error ...
It is reported
Thanks
Brian
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The code should do the same job as your code, the idea was that if the same problem was found then the machine is at fault not the code, if the new code worked ok then it is a lcam fault.
Graham.
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Graham, I'll give it a try.
Brian, I agree, but I don't use tool diameter compensation but do think it's a toolpath error. I measured the excess move as 0.89mm but that could easily have been 1mm (2mm cutter but also diameter of top small hole) when cut. Strange as it didn't happen on an earlier iteration. Possibly the vertical move from the small hole to the top horizontal line being miscalculated in Mach3 but correct values showing on displays???
Final article (after judicious use of a file :) )
two of these:-
(http://www.pbase.com/image/77917117/large.jpg)
and one of these:-
(http://www.pbase.com/image/77917160/large.jpg)
plus one of these:-
(http://upload.pbase.com/image/77049240/large.jpg)
which started life as an old audio power amp case (back panel now modified)
make up an 8x230W per channel high-end audio Home Theatre amp from commercial modules.
Would have been quicker to use a saw and drill press, but much more satisfying to use CNC toys :) :) :)
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I checked it in the new rev and it is working :)
So you will be all set when the new one is out in about a week...
Thanks
Brian
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Thanks Brian. I assume that's a new rev of Mach3 as opposed to lazycam as the Gcode looked OK?
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I think that you will find that Mach3 should be fixed now...
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Brian,
Just tried it with version 2.00.067. Better, but the error has moved to the final line of the outer cut and has an error of +0.60mm :( I don't use any cutter compensation at all.
(http://www.pbase.com/cdyckes/image/77975395/large.jpg)
On a Lazycam related issue. The file I sent you does a rapid plunge to -1.5 (start depth) followed by a feed to -3 before each cut. I tried this setting as if I set a start depth of 0 then Lazycam generated a pass a 0 height before doing it's first feed to -1.5. I've tried various settings and the rapid/plunge settings seems a little strange, especially for arcs. Is this use error, or something that needs optimising? I have RTFM but it's not clear what's needed here.
EDIT: Test project zip file added to show rapid/feed z moves
Thx
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I have just ran your file here and it is fine...
ccould you please run this file and tell me what it is doing?
G0 z1.0
X5.0
G01 X10 F50
Y5
X0
Y0
X5
M47
Run that file for about 10 reps and tell me if it is out of position? I think that you are going to find that the Y axis is moving its position (Electrical noise) OR that you have backlash in your screws...
To see what is going on please put a pen in the spindle and draw the path.
Thanks
Brian
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Brian,
I'll try and rig up a pen and try that after work.
For what it's worth, all the holes measure correctly from the lower edge to within .02mm (which is amazingly accurate). RH portion of the top cut is now straight.
Wouldn't the top righthand cut slope upwards if backlash was the problem (it did slope down before the Mach3 fix whilst the left portion of the top cut was straight and parallel to the bottom cut).
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Ran the test loop some 50 times in total, manually cranking the z-axis down every 10th pass to allow for pencil wear. Got this:-
(http://www.pbase.com/cdyckes/image/78005359.jpg)
Picture was slightly out of square and I haven't photo adjusted, but actual result looks a good rectangle to me.
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Well that look nice :) hmmm I don't see where your error is