I seem to be having an issue between how much fire control is commanding on z axis and how much its actually moving, let me explain. I had a quick cut this morning but noticed the cut height was exceptionally low. I checked the program its called out at .150 pierce / .06 cut, my normal settings. After the program was done i wrote a quick program to run just the IHS sequence. As I’m doing this i noticed what should be the pierce height is closer to cut height and cut height almost on the plate.
I had the idea to check all the axis with an indicator just incase something is up. X and Y both move to the commanded amount +/- a few thousandths, all good. Z, i put into .125 step mode, 1 step moved .029. Another step another .029. Its almost like the steps per inch calibration is some how incorrect.
I’ve uploaded a picture and my test program. In the photo the darker steel piece is 16 ga or .064 thick for reference. Spring back is a non issue as I’m using 1/4 inch stock that is weighted down to prevent movement and my IHS switch is working and being detected by fire control.
Any ideas? I’ve already searched the forums and found plenty of IHS problems but none like this.
Can you tell if there is any slipping with the z- motor coupler?..I know this would be hard to monitor.
Perhaps the z-axis motor is failing.
Dirty/loose connections on the z-axis plug at the enclosure.
It sounds like you did very careful testing with the “step” movement. Could you try the same with X or Y? If they are also off, maybe the power supply is failing.
Does there seem to be any sloppiness with the IHS contacts? Be careful: this is when I moved the one wires and that caused the nut to loosen and then you have to get inside that carriage to effectively re-tighten. What I am thinking is that the contact is loose enough that it prematurely re-establishes the connection and falsely signals the torch had lifted off the metal.
It sounds like a stepper motor driver issue. I doubt that a failing motor or a slipping coupler would provide a consistent error.
Try switching the Z plug to the X and see if it moves the correct distance when plugged into the X driver. You’ll have to move it with the X, of course.
Also try moving the X axis with the Z driver and see if the issue follows the driver.
Jim,
A slipping coupler waa my first thought so while it was powered and in its holding state i checked for slippage, i couldnt see any. I will check the switch next time im at the machine though it seems to be functioning correctly. I did try a similar test with x and y and they move as they should.
Ds690,
Im leaning toward driver myself and will try the swap test next time im at the machine although ill have to remember to take into account the different travel per revolution for x and y versus z or maybe just switch the plugs on the drivers themselves. This brings up an interesting question, seeing how Im almost exactly 1/4 of what i need to be moving, i wonder if during an update it was programmed for all axis having a 4 start lead screw and not just x and y? Just a thought, unfortunately im not aware of anyway to check that.
The Z axis lead screw pitch is not mentioned in the documentation, but I’m pretty sure it is 3/8-8 4 start. All of the other axis use a 1/2" per revolution screw regardless of the number of starts. The Pro table uses a 1/2-10 5 start on the X, which also results in 1/2" per revolution of movement.
I got it fix, strange what it was though. Tried the suggestion of swapping the cables on z with another. Manually moving with step mode, had accurate moves, ok, so the problem is with the driver. Opened the electronics box and swap the control and motor plugs over to the y driver to check IHS, worked perfect.
Started looking at the driver for z noticed one of the dip switches for setting parameters didn’t look quite right. I just about touched it and it jumped to the off position. Looking at the chart that would have set it at 6400 steps/ rev. Just fir giggles i flipped it back to the 1600 position, reconnected all the wiring the right way tested it and everything worked perfectly.
Now how that switch got tripped is beyond me but lesson learned here, make sure the settings are right. Ill be getting some drivers ordered incase those switches are getting weak.
Is your table on wheels? Just guessing, but maybe the switch was between positions and you hit a bump when wheeling the table around. The impact could have jarred the switch into the wrong position.
Wow! I remember someone had a similar situation over a year ago. Really rare. Glad you figured it out. This will be a good case for adding to the list of possibilities.
