SO3 crashing into material

Hey,
I’m fairly new in the CNC community and would appreciate some advice.

My machine (SO 3 XXL) is occasionally running into material after it “stutters” a bit. The workhold isn’t the problem, all screws and belts are fairly tight and the wheels + belts are lubricated.
It has happend on X and Y movement, approximatly once all 15minutes while running a job.
Has someone had this problem before or can give me some advice where to dig deeper?
Every helping mind is highly appreciated

~ Steffen


Look at your feeds and speeds. It appears you are losing steps and thus the errant cut. Also check that your bit is not coming loose and getting lower. But if that jog up into the material would indicate that you are losing steps and cutting where it is not supposed to. As you mention belt tightness and stepper motor pulley set screws could also be the problem. Put a magic marker across the pulley through the center shaft. Jog back and forth and see if the line is still aligned. One of the set screws should be on the flat of the stepper motor and the other just on the round part of the shaft. Since you have an XXL SO3 move the gantry all the way to the back and lift up on your Y belts. You should be able to get your finger under the belt and feel tight. Most importantly are the belts feeling the same tension on your finger under the belts from side to side. Also on the X move the router to one end or the other and do the same lifting of the belt and see if it is feeling tight with your finger under the center of the belt. You depth of cut does not seem too much but if this is the first pass maybe reduce your depth of cut or use the stock setting.

A further consideration beyond feeds and speeds and mechanics of the machine is tooling engagement — are you cutting a slot just as narrow as the tool?

Where possible avoid slotting and add geometry and cut as a pocket

and/or

and consider leaving a roughing clearance and taking a finishing pass.

Hey gdon_2003 and WillAdams,
thanks for your advice!

I don’t yet understand 100 % of the technical terms in english (which is a foreign language for me).

However I tried to check everything as you described:

  • Feeds and speeds: are set as the default settings which are provided by carbide 3D.
  • Bit/end mill: is not loose
  • belt tightness: should be on point. I made some minor adjustments to tighten them exactly the same way, but I doubt it changed anything
  • Step motor pulley set screws: I couln‘t find a 1.5mm Hex. So i couldn‘t check on the tightness oft he pulley set screws yet. However after marking a point and joging arround it still seems to be in the same position. Unfortunately my stepper motors don’t have a flat side. The entire thing is just round (see attached picture) Can I check/adjust anything else about the stepper motors and its pulley set screws?

Moving X and Y by hand at a rather fast speed leads to the same „stuttering“ which seems to be the loss of steps. Is that normal or shouldn’t you hear that sound if you move it around at a fast pace – at least I guess it should be smooth ^^‘‘

The cutted slot is just as narrow as the tool. (6mm/ ~1/4“)
Tomorrow I can try the same cut with different setting.

Thanks a lot so far and best regards!

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.