Simultaneous 4th Axis Cut Moving Too Slow
- IronManDylan
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31 Jul 2024 06:02 #306462
by IronManDylan
Simultaneous 4th Axis Cut Moving Too Slow was created by IronManDylan
Hi,
I haven't asked a question in a while but I am machining something new on my mill with my 4th axis and it is requiring me to do a simultaneous 4th axis cut which I have not done before. I had some issues simply getting to tool path to post correctly. I finally figured that out but now the cut is going extremely slow. The velocity is supposed to be cutting at 46 in/min. The post processor is indeed posting this velocity with "F46", however the cut is going extremely slow. Since the post processor is outputting the correct velocity I do not think it is the post processor that is at fault but something going on with linuxcnc. The endmill is taking such a small cut that the aluminum is coming off as fine dust. The "vel" on the display is showing around "2" (I am not sure if this is in inches/min or not).
In my INI folder the max angular velocity is set to "33" and I can jog the 4th axis faster than what is going on in the cut. So I do not think this is the problem.. I have outputted code in both the normal velocity profile and in the inverse profile and neither seem to help.
The cut is just a circular arc but the center of the arc is not centered with the rotational axis. The tool path is just a contour where I need the tool to remain perpendicular to the arc.
I appreciate any help or words of wisdom!
Best,
-Dylan
I haven't asked a question in a while but I am machining something new on my mill with my 4th axis and it is requiring me to do a simultaneous 4th axis cut which I have not done before. I had some issues simply getting to tool path to post correctly. I finally figured that out but now the cut is going extremely slow. The velocity is supposed to be cutting at 46 in/min. The post processor is indeed posting this velocity with "F46", however the cut is going extremely slow. Since the post processor is outputting the correct velocity I do not think it is the post processor that is at fault but something going on with linuxcnc. The endmill is taking such a small cut that the aluminum is coming off as fine dust. The "vel" on the display is showing around "2" (I am not sure if this is in inches/min or not).
In my INI folder the max angular velocity is set to "33" and I can jog the 4th axis faster than what is going on in the cut. So I do not think this is the problem.. I have outputted code in both the normal velocity profile and in the inverse profile and neither seem to help.
The cut is just a circular arc but the center of the arc is not centered with the rotational axis. The tool path is just a contour where I need the tool to remain perpendicular to the arc.
I appreciate any help or words of wisdom!
Best,
-Dylan
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31 Jul 2024 08:25 - 31 Jul 2024 08:26 #306474
by Aciera
Replied by Aciera on topic Simultaneous 4th Axis Cut Moving Too Slow
Two things to note here.
1. Since this involves blending linear and angular joints try using inverse time (G93) instead of G94
2. Generally the CAM/PP will generate 4axis Gcode made up of short line segments. Since the MotionPlanner in LinuxCNC will fall back to one line look ahead for any move involving any other than X,Y,Z axes it is important that the line segments are not made too short. So to speed things up you should also try to get the CAM to generate longer line segments.
1. Since this involves blending linear and angular joints try using inverse time (G93) instead of G94
2. Generally the CAM/PP will generate 4axis Gcode made up of short line segments. Since the MotionPlanner in LinuxCNC will fall back to one line look ahead for any move involving any other than X,Y,Z axes it is important that the line segments are not made too short. So to speed things up you should also try to get the CAM to generate longer line segments.
Last edit: 31 Jul 2024 08:26 by Aciera.
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31 Jul 2024 09:10 #306478
by IronManDylan
Replied by IronManDylan on topic Simultaneous 4th Axis Cut Moving Too Slow
Wow aciera youre right again. I cant believe that was the issue. But if anyone is seeing this in the future turn up your smoothing and tolerence in fusion 360.
My line segments are about 1 to .5 thou now (they were down at about a 10th before) and i can get up to somewhere about 60-80 percent of my feedrate which is way faster. Theres work to be done if I needed to cut a bunch of aluminum but this is a test cut for inconel, so this speed will work just fine!
Thank you sir!
My line segments are about 1 to .5 thou now (they were down at about a 10th before) and i can get up to somewhere about 60-80 percent of my feedrate which is way faster. Theres work to be done if I needed to cut a bunch of aluminum but this is a test cut for inconel, so this speed will work just fine!
Thank you sir!
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