I imported your DXF on a 3D environment, it had double lines in it, can you tell me what`s the exact measurement on your drawing? let me try to do a custom CAM on it and post back the G-code here for you to try on your machine
I am using VCarve Pro to machine 4 simple arcs to create one cycle of a perfect sine wave. I save the tool path using the Arcs post processor for WinCNC and then machine the path with my ShopSabre servo controlled router. In one of the arcs I get an imperfect bump that is consistent from part to part. I have tried fitting a spline to the arcs and machining that path but the bumps are then more pronounced. The only thing I have found to help is to export the g-code using the standard GCode post processor instead of the arcs version. It still isn't perfect however. I know this is within the capability of my machine to produce so can only suspect it is within the G code itself. If anyone can suggest how to fix it I would appreciate your expertise.
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I imported your DXF on a 3D environment, it had double lines in it, can you tell me what`s the exact measurement on your drawing? let me try to do a custom CAM on it and post back the G-code here for you to try on your machine
There are duplicate arcs, but I don't see anything wrong with the .dxf file that would cause "bumps".
Gerry
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Sorry about the double lines. I did clean the geometry in VCarve Pro before exporting the g-code though. I contacted ShopSabre and they told me not to use the WinCNC post-processor but the ShopSabre post-processor instead. I had no idea they had their own! I did that last night and the part was definitely improved. I need to make several more tonight to confirm.
Well it doesn't appear that the shopsabre post processor fixed the problem. The exact measurements for the arc series are:
1. Peak to trough is 127mm
2. Arc radius = 199.71mm
3. distance between top and bottom arc = 584.2mm
4. There are four arcs
The radius of the arcs in the dxf is 399.42mm.
I really don't know what the problem is. The .dxf doesn't tell anyone anything, as it really has nothing to do with your issue. The problem is either in the g-code, or your machine.
Can you post a pic of the issue, and the g-code?
Gerry
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The end mill is 3/8" diameter. The material is 1/2" MDF. If you connect a straight line to the top and bottom set of arcs to complete the profile, that is what I am trying to cut out. Thanks for your help!
Gerry,
I'll take some pics tonight and attach them but for now, here is the latest gcode.
Stan
Two things I would do.
It looks like you are cutting 4 panels at a time. There is no space between the panels (except the 3/8" for the bit). I'd separate them by about 1/8", so 1/2" between them.
I would ramp in, rather than plunging.
I think the plunge move is probable putting the marks on your panels, but I'm not sure.
Gerry
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Thanks Gerry. I have been doing a ramp lead in rather than plunging. I had just forgotten to do that when I created this file. The plunge is on the flat side though and the 'bumps' are on the arcs, right at the transition from one arc to the next. The imperfection isn't on every arc transition however, which makes it more difficult to diagnose.
You can try this code sir, Im not really sure of the dimensions though I just set it to 584.2mm, I made it into two passes to try it out on your machine and test it out. I also just copied the speed and feed of the G-code you posted, the plunge rate is 300 then the cut speed is 600
Code:( T3 : 9.5 )G21 G90 G91.1 G64 G40 G0 Z3.0 ( T3 : 3.0 ) T3 M6 ( First Pass ) G17 M3 S1000 G0 X0.0 Y0.0 G0 Z1.0 G1 F300.0 Z-6.35 G1 F600.0 Y-593.8789 G1 X18.6615 Y-593.2409 G1 X32.5577 Y-591.8112 G1 X46.3239 Y-589.4358 G1 X59.8956 Y-586.1258 G1 X73.2096 Y-581.8966 G1 X86.2036 Y-576.7679 G1 X98.8169 Y-570.7639 G1 X110.9907 Y-563.9124 G1 X122.668 Y-556.2454 G1 X133.7943 Y-547.7989 G1 X144.3177 Y-538.6122 G1 X154.0188 Y-528.8988 G1 X173.6506 Y-510.5416 G1 X195.4041 Y-495.1702 G1 X219.0497 Y-482.9067 G1 X244.1461 Y-473.9798 G1 X270.2251 Y-468.5561 G1 X296.8 Y-466.7369 G1 X323.3749 Y-468.5561 G1 X349.4539 Y-473.9798 G1 X374.5503 Y-482.9067 G1 X398.1959 Y-495.1702 G1 X419.9494 Y-510.5416 G1 X439.5812 Y-528.8988 G1 X449.2823 Y-538.6122 G1 X459.8057 Y-547.7989 G1 X470.932 Y-556.2454 G1 X482.6093 Y-563.9124 G1 X494.7831 Y-570.7639 G1 X507.3964 Y-576.7679 G1 X520.3904 Y-581.8966 G1 X533.7044 Y-586.1258 G1 X547.2761 Y-589.4358 G1 X561.0423 Y-591.8112 G1 X574.9385 Y-593.2409 G1 X593.6 Y-593.8789 G1 Y0.0 G1 X574.9385 Y-0.638 G1 X561.0423 Y-2.0677 G1 X547.2761 Y-4.4431 G1 X533.7044 Y-7.7532 G1 X520.3904 Y-11.9824 G1 X507.3964 Y-17.111 G1 X494.7831 Y-23.1151 G1 X482.6093 Y-29.9666 G1 X470.932 Y-37.6335 G1 X459.8057 Y-46.08 G1 X449.2823 Y-55.2667 G1 X439.5812 Y-64.9801 G1 X419.9494 Y-83.3373 G1 X398.1959 Y-98.7087 G1 X374.5503 Y-110.9723 G1 X349.4539 Y-119.8992 G1 X323.3749 Y-125.3228 G1 X296.8 Y-127.142 G1 X270.2251 Y-125.3228 G1 X244.1461 Y-119.8992 G1 X219.0497 Y-110.9723 G1 X195.4041 Y-98.7087 G1 X173.6506 Y-83.3373 G1 X154.0188 Y-64.9801 G1 X144.3177 Y-55.2667 G1 X133.7943 Y-46.08 G1 X122.668 Y-37.6335 G1 X110.9907 Y-29.9666 G1 X98.8169 Y-23.1151 G1 X86.2036 Y-17.111 G1 X73.2096 Y-11.9824 G1 X59.8956 Y-7.7532 G1 X46.3239 Y-4.4431 G1 X32.5577 Y-2.0677 G1 X18.6615 Y-0.638 G1 X0.0 Y0.0 ( Second Pass ) S1000 G1 F300.0 Z-12.7 G1 F600.0 Y-593.8789 G1 X18.6615 Y-593.2409 G1 X32.5577 Y-591.8112 G1 X46.3239 Y-589.4358 G1 X59.8956 Y-586.1258 G1 X73.2096 Y-581.8966 G1 X86.2036 Y-576.7679 G1 X98.8169 Y-570.7639 G1 X110.9907 Y-563.9124 G1 X122.668 Y-556.2454 G1 X133.7943 Y-547.7989 G1 X144.3177 Y-538.6122 G1 X154.0188 Y-528.8988 G1 X173.6506 Y-510.5416 G1 X195.4041 Y-495.1702 G1 X219.0497 Y-482.9067 G1 X244.1461 Y-473.9798 G1 X270.2251 Y-468.5561 G1 X296.8 Y-466.7369 G1 X323.3749 Y-468.5561 G1 X349.4539 Y-473.9798 G1 X374.5503 Y-482.9067 G1 X398.1959 Y-495.1702 G1 X419.9494 Y-510.5416 G1 X439.5812 Y-528.8988 G1 X449.2823 Y-538.6122 G1 X459.8057 Y-547.7989 G1 X470.932 Y-556.2454 G1 X482.6093 Y-563.9124 G1 X494.7831 Y-570.7639 G1 X507.3964 Y-576.7679 G1 X520.3904 Y-581.8966 G1 X533.7044 Y-586.1258 G1 X547.2761 Y-589.4358 G1 X561.0423 Y-591.8112 G1 X574.9385 Y-593.2409 G1 X593.6 Y-593.8789 G1 Y0.0 G1 X574.9385 Y-0.638 G1 X561.0423 Y-2.0677 G1 X547.2761 Y-4.4431 G1 X533.7044 Y-7.7532 G1 X520.3904 Y-11.9824 G1 X507.3964 Y-17.111 G1 X494.7831 Y-23.1151 G1 X482.6093 Y-29.9666 G1 X470.932 Y-37.6335 G1 X459.8057 Y-46.08 G1 X449.2823 Y-55.2667 G1 X439.5812 Y-64.9801 G1 X419.9494 Y-83.3373 G1 X398.1959 Y-98.7087 G1 X374.5503 Y-110.9723 G1 X349.4539 Y-119.8992 G1 X323.3749 Y-125.3228 G1 X296.8 Y-127.142 G1 X270.2251 Y-125.3228 G1 X244.1461 Y-119.8992 G1 X219.0497 Y-110.9723 G1 X195.4041 Y-98.7087 G1 X173.6506 Y-83.3373 G1 X154.0188 Y-64.9801 G1 X144.3177 Y-55.2667 G1 X133.7943 Y-46.08 G1 X122.668 Y-37.6335 G1 X110.9907 Y-29.9666 G1 X98.8169 Y-23.1151 G1 X86.2036 Y-17.111 G1 X73.2096 Y-11.9824 G1 X59.8956 Y-7.7532 G1 X46.3239 Y-4.4431 G1 X32.5577 Y-2.0677 G1 X18.6615 Y-0.638 G1 X0.0 Y0.0 G0 Z3.0 G0 X0 Y0 G0 Z0 M5 M30
Is the machine stuttering, or pausing, where you get the bump? My guess is that it has to do with the code, and WinCNC is pausing when it shouldn't be?
I see some instances where your code has I8.0499, and I8.05. These should probably be the same. I'm thinking that some minor math issues are causing WINCNC to see tangent arcs as being not tangent?
Gerry
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Gerry,
Yes the machine appears to have a slight stutter at the location of the defects. I haven't checked the code line-by-line for the file which I attached earlier, but I had checked it for the one I am attaching below, which was generated using the WINCNC post-processor, and everything appears to be perfectly symmetrical, yet I still see the defect. Last night I tried some settings as suggested by ShopSabre in the wincnc.ini file, having to do with speeds and accelerations around the arcs. They didn't help. This is a puzzler!
Stan
N75 G00 X0.000 Y0.000
N80 G00 Z0.800
N85 G00 X0.100 Y-0.087 Z0.200
N90 G01 Z-0.600
N95 G01 X23.100
N100 G03 X23.287 Y0.100 I0.000 J0.187
N105 G03 X20.728 Y5.987 I-8.050 J0.000
N110 G02 X18.287 Y11.600 I5.235 J5.613
N115 G02 X20.728 Y17.213 I7.675 J0.000
N120 G03 X23.287 Y23.100 I-5.490 J5.887
N125 G03 X23.100 Y23.287 I-0.187 J0.000
N130 G01 X0.100
N135 G03 X-0.087 Y23.100 I0.000 J-0.187
N140 G03 X2.472 Y17.213 I8.050 J0.000
N145 G02 X4.913 Y11.600 I-5.235 J-5.613
N150 G02 X2.472 Y5.987 I-7.675 J0.000
N155 G03 X-0.087 Y0.100 I5.490 J-5.887
N160 G03 X0.100 Y-0.087 I0.187 J0.000
N165 G00 Z0.200
N170 M5
I am just finding time to coming back to this problem. See attached pix which show the bumps at the tangency point between the two arcs. I have tried lowering the accelerations, and velocities. I have tried fitting a bezier spline. I have tried importing the dxf geometry from solidworks into vcarve pro and have also created the geometry natively in vcarve. I have put a 1mm line between the two arcs. Nothing fixes the problem.
What happens when you cut a circle. Do you have issues with them being round or defects at the quadrants?
Ben
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I machined a circle tonight which was created using the same arcs from the problem file. It was perfect--no bumps at the intersections. Of course, the difference is that with a circle, the arcs are all facing the same direction, whereas the arcs are going in the opposite direction at the tangency points, like a sine wave.
Do you have a constant velocity mode available? Or can you post the file as ''convert arcs to lines'' and run the part as all G1 moves?
Is it maybe a backlash or backlash compensation issue?
Gerry
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Jim, I have fitted a bezier spline to the arcs and machined those. Is that what you mean? This yielded worse results.
Gerry, good question about backlash. I hadn't thought of that, even though I should have. I am currently trying to get the factory to machine the same profile and if they see the problem too, this could be a reason.