5 axis CNC Router/3d printer

[TomKerekes]

Hi George,

loaded your sent Help file. Works in Kmotion but it seems to go to the
help on line files when running Kmotion Cnc. Is that correct?

No it shouldn't. What give you the indication it is doing so? What Version did you copy it to?

Does RTCP get disabled when program runs in G0?

no

I am having motor fault problems with a program I am trying to run.
I have attached a snippet of a program that seems to cause axis run away.
The program gets to around line 9150 and the B and Z axis makes a very fast movement
and then it trips a motor fault. Not sure why things make a sudden jump. I played
with velocity settings in both kmotion and KmotionCNC. Ran simple test program to make sure
that none of the axis can be over driven. Still get this sudden high speed jump. Not sure
if this is a posting problem or something in the RTCP setup. I have ran large programs with beautiful
5 axis motion with no problems prier to this.

I don't know. What Axis Trips? That line does a significant B motion of ~ -30 degrees. With a relatively small XY motion. So the XY movement will attempt to move at the specified feed rate which will cause the B axis to moved very rapidly. But the trajectory planner should slow down based on the constraints (Acceleration and Velocity) you have specified for B. Are you sure you have appropriate limits on B's Acceleration and Velocity in KMotionCNC's Trajectory Planner settings?

[George Butty]

1)Hi Tom, I am running ver 435h I guess I should update to the latest.

2)Have you made any changes to the RTCP in the latest version?
I have attached a copy of the simple gcode I use to test the machine. I ran
the program with G01 active on first video link and then I ran the same program
with G00 on the second video. As you can see RTCP is not too happy running
with the G00 rapid mode.

With G01 https://www.youtube.com/shorts/szZka9htlHM
With G00 https://www.youtube.com/shorts/o05CwaD0ceM

George

[TomKerekes]

Hi George,

I think you need to select the Rapids as Feeds Option. Otherwise just the beginning and end points are RTCP corrected with linear motion between.

[George Butty]

Hi Tom, rapids to feed only makes things worse. G0 move instantly faults out the linear axis. It seems
to be over riding the default velocity settings in Kmotion. I have them set to 80000 and I know the machine
can comfortably go as high as 175000 in all axis without any problems. The other thing that is strange is
running my simple test program that I sent you, now faults the motors when I try to run the program in G0 mode.
Can not get it to run like the video I sent you. Not sure if this is related but even in G1 mode
the program runs but the feed rate for the rotary axis goes roughly half of the linear feed rate set.
I know my rotary and linear axis combined can handle far more speed than what it is doing.
George

[TomKerekes]

Hi George,

I think Rapids as Feeds is absolutely required.

What are all your current settings? Pivot length? Tool Length?

I had thought that feed rates were automatically limited to the constraints of all axes including RTCP induced motions, but they are not. We will look into adding this.

When Rapids as Feeds is selected, the KMotionCNC Trajectory Planner settings are used to limit velocity and acceleration. I think you will need to reduce the velocity and acceleration settings for BC such that it doesn't exceed the XYZ capabilities of the system.

I think if the maximum pivot length, including tool, is R

Then using the lowest XYZ axis's Velocity limit multiplied by 360 / (2 PI R) and set the BC Trajectory Planner's Velocity to that value, and repeating the same thing for Acceleration the XYZ axes should not fault.

For example if R is 10in and the lowest Velocity limit is 8 in/sec then:

10 x 360 / (6.28 x 8) = 72 deg/sec

And similarly for Acceleration.

Note the XYZ limits Acceleration must be those capable with infinite Jerk.

HTH

[George Butty]

Hi Tom, Managed to get things running in Rapids to feed mode. Once you
showed me the calculations, then I could see that the units was throwing me off in the
velocity setting. At this point things are working well.
Thanks
George

[George Butty]

Hi Tom, I am doing some work on my plasma cutter. It runs Mach3 with Tecnic closed loop servo motors
with your dual SnapAmp drivers Ver4.33. I was running the Step Response option and it was working fine.
Next day I came to run it again and starting Kmotion. A Persist.ini error can't read file came up. Checked file and
it was empty. I reloaded Data directory and started Kmotion. When I went back to the step response option and
reinput data for ch0, step responce does not get the axis to respond. The axis gets disable with no movement.
Do I need to reload Kmotion or is there a way to repair the step response without reloading Kmotion. I am paranoid
of having to debug Kmotion if it does not start up properly. Also if I do not Load Mach3 features, will the existing Mach reconnect
the way it was. I use this machine everyday and at this point it runs fine with the old settings. I would like not to spend days to get it going again if I run into problems, if possible.

George

[TomKerekes]

Hi George,

Restoring the data directory should restore all settings.

Note you must run a C Program to enable the current limit settings in SnapAmp before using the Step Response Screen.

One LED (I'm Alive) should be blinking and the other (Current/Temperature fault) should be off.

[George Butty]

Hi Tom, got step response going for my plasma. I did some tuning with some pretty good results.
One thing I am having problems with is a buzzing of the axis motors when stopped. Would be nice to
get ride of that. I am not sure how to go about playing with IIR filters. Seems to do some thing but
don't really know where to start. Values don't really mean anything to me.(frequency, Q) Not sure if I set filter 0,1,2
or just one of the filters?
George

[TomKerekes]

Hi George,

Filters are not likely to help. You might read this Topic on servo dither.