Hello all! Great stuff you all have going on here.

(Jack Daugherty) #1

Hello all! Great stuff you all have going on here. I recently purchased the OX 1500 x 1500. I purchased the all in one simple controller with it as well. I finally got around to making some cuts the other day and it seems to be missing a couple of steps during the process. It went back to the point of origin after the cut was done, and it was about .25" off in bith the X and Y axis’s.

The controller should be set up for my machine, and maybe it is, but am getting missed steps anyhow. I am using CUT3D software and using one of the pre-installed gcode post processors simply called “G Code Inch” I am using a .25" 3 flute, upcut endmill bit. Feed speed @ 100 IPM, with .05 inch pass depth and spindle speed @ 12000 rpm.

Material is Red Oak. I originally tried it at .1 inch pass depth @ 200 IPM, but I the thought the spindle was going to break lose because of the terrible shuddering on some of the passes. I changed to a .25" 2 flute center cutting mill, and dropped the speeds down to the previously mentioned settings, and it seemed to cut much smoother, but the missed steps are still there.

I believe those settings should have been okay to use, but the results tell me otherwise. Are there any settings within GRBL, or Bcnc I should try changing, or do I need to drop my speeds even farther down? Thanks

(Darryl Blandford) #2

Try slowing it down by 75%, and see if it still drops steps. If not, slowly increase the speed until it does start to skip, then back off the speed by 15%. If it still skips at 25% speed double check the toothed pulleys (if belt driven), or shaft couplings (if leadscrew driven) are all fully tightened.

(Nathan Lucier) #3

Make sure the set screws in your belt pulleys are actually still tight. I ran into that when first running my OX 1500x1500. I eventually changed them out for cap screws so that I could get a real sized allen wrench into the things to tighten with satisfaction.

(Jack Daugherty) #4

@Nathan_Lucier @Darryl_Blandford I used the adjustment slider within Bcnc to set my feed speed to 80 IPM, and let it do it’s thing. It still finished a bit off of the starting zero by about .15 on the X axis. Everything is as tight as the set screws allow me to get it. I am going to need new ones, because they are starting to strip out with the tiny allen wrench.
I did notice that when I try to dial in my zero, I can’t make any adjustments under .02" It triggers the stepper motor, but no physical movement occurs. It shows it moved in Bcnc though. I used a strip of paint on the motor shaft across the pulley to see if it was slipping, but it is not.
I found that setting $1=255 is supposed to give full holding torque on the stepper in GRBL. It was set to 250 already so that probably didn’t do much.
I also noticed that I can get the pulley’s to turn with my fingers without too much difficulty, while powered on. That is what makes me think it’s possibly a driver set up issue. Like maybe full step, half step, micro stepping settings?? Maybe it needs more juice to the motors? Not sure how these are set now though, and if it’s capable with the provided driver boards.
Feed depth of .05" @ 80 IPM just seems so much under what I should be able to get. At least according to the feed/ speed charts I’ve looked at. I realize every machine has it’s sweet spots though.

Just some thoughts I had

(Jack Daugherty) #5

@Hobby_Fab Ah, I did see that about the time applied, but didn’t see that 255 was constant. I did set it to 255 anyhow. Thanks for the info.

(Nathan Lucier) #6

@Jack_Daugherty Being able to turn the motor shafts with your fingers while they are on would be my first worry. Definitely something not right there. Being able to do just that was what made me realize that not only were my set screws loose, one of them had fallen out and was under the X axis belt. That was when I went to Ace and got the cap screws to replace them (“He doesn’t need help…he is going to the Metric Wall to piece together more hardware for his CNC Router or for his FIRST FRC Robotics team.” One of the old guys there to a new hire. They love me there).

(Jack Daugherty) #7

@Nathan_Lucier I did set the command line to $=255, and that did seem to add some holding torque. I also bought some bigger set screws that I haven’t yet drilled and tapped the pullies for. Last resort, or likely while I’m doing the screw upgrade, I happen to have a set of 3, 420 oz in steppers not being used :wink:. X and Y axis’s should be taken care of with that. We’ll see what happens.