Movement of the X or Y axis causes movement of the other axis.
After converting my MK4S to Core One, I had very good printing results until two days ago. From one print to the next, my Core One is no longer usable. First, I noticed that the purge line is no longer in the front right corner. Instead, it is offset diagonally to the left rear, about 1/4 of the way inside the sheet metal. The print then also starts too far back on the left.
When I move X or Y manually, I see that when Y moves to the stop, the extruder shifts a little in X and vice versa. I have now moved the axes by hand with the motors switched off. I noticed that the Y-axis is sticky in several places. There is a clearly noticeable resistance. I am not sure whether this is coming from the motors or the shaft/bearings. After a few movements, however, this disappeared and it is moving normally again.
However, the next print failed again.
It seems to me that this could be a common problem with Core-XY, but I don't know the term for it. Let alone the cause... I also can't remember reading anything about it here in the forum.
I would be very grateful to know where this behavior comes from and how to stop it.
Thank you very much!
Stefan
Best Answer by Stefan Krister:
I found the cause. The pulley on the right motor was loose. It was still turning with the motor shaft, but it was slipping back and forth on the shaft.
RE: Movement of the X or Y axis causes movement of the other axis.
Check:
Belt tension (belt loose, stretched due to excessive tension)?
Idler pulleys (sluggish, rubbing against the bracket)?
Motor pulleys (grub screws loose)?
Linear bearing (mine needed to be lubricated because it suddenly became stiff)?
RE:
After converting my MK4S to Core One, I had very good printing results until two days ago. From one print to the next, my Core One is no longer usable. First, I noticed that the purge line is no longer in the front right corner. Instead, it is offset diagonally to the left rear, about 1/4 of the way inside the sheet metal. The print then also starts too far back on the left.
When I move X or Y manually, I see that when Y moves to the stop, the extruder shifts a little in X and vice versa. I have now moved the axes by hand with the motors switched off. I noticed that the Y-axis is sticky in several places. There is a clearly noticeable resistance. I am not sure whether this is coming from the motors or the shaft/bearings. After a few movements, however, this disappeared and it is moving normally again.
However, the next print failed again.
It seems to me that this could be a common problem with Core-XY, but I don't know the term for it. Let alone the cause... I also can't remember reading anything about it here in the forum.
I would be very grateful to know where this behavior comes from and how to stop it.
Thank you very much!
Stefan
The skewed purge line implies your gantry is bent (or severely bent) and no longer parallel to the edge of the print sheet. This will cause all kinds of problems. I would first start by completely loosening the belt tension. Next move the gantry to the front of the printer and check if it is parallel to the frame. If not then manually bend it until it is. Next loosen the 4 screws (but not completely) on either side of the L bracket that connects the linear rail to the bearing sleeve. Move it back and forth along the Y direction several times (front to back) checking for any resistance. If there is still resistance to sliding it could indicate a bad bearing. If there is none, slide the gantry to the front of the printer and tighten the screws. Confirm that the gantry is still square. Next tighten the belts and tune them but do it slowly and evenly on both sides making sure that the gantry doesn't bend again.
RE: Movement of the X or Y axis causes movement of the other axis.
I found the cause. The pulley on the right motor was loose. It was still turning with the motor shaft, but it was slipping back and forth on the shaft.
RE: Movement of the X or Y axis causes movement of the other axis.
OK, I'll give myself a pat on the back for being on the right track... 😊
It had to be that way, because the error appeared suddenly.
RE: Movement of the X or Y axis causes movement of the other axis.
When you tighten the pulley you MUST tighten the set screw on the flat when the other set screw is loose. FLAT FIRST is the mantra you want to remember.
The screw on the flat sets the position of the pulley and the screw must be perpendicular to the shaft and tip must be flat against the shaft flat. The second set screw that hits the round serves only to lock the other set screw in place. If you tighten the screws round first, the screw on the flat will wobble and eventually come loose, no matter how much torque you apply.