sliding Y axis - SOLVED

[giraffneck 0]

I am relatively new to 3d printing. I have a UM original with 1.5.7 board. My problem is that when I print large prints the y axis slides toward the front of the build platform. It starts to slide from the very start of the print and every layer seems to slide an even amount. I let a big print go till it hit the front limit and it started to slide to the left along the x axis in the same even amount. I can print small prints flawlessly, even several small prints at the same time taking up a large area, but the larger the print the larger the slide I get. I have greased all the rods, made sure the set screws were tight and that they were not slipping using a marker, reloaded cura and the firmware, tried a different stepper driver for the y motor, and tried a different arduino.

Please help!!!! I have no idea what it could be.

 

[gr5 2,266]

Is the print moving (not stuck to the bed) or is the print "leaning" to the front as the head gets closer and closer to the front. If the later then you need to tighten all the little black set screws in the pulleys. There are 6 (SIX!) set screws on the Y axis and the most likely ones that are slipping are the 2 on the short belts (the one on the motor and the one on the other end of the short belt.

 

[giraffneck 0]

The print sticks nicely to the bed and none of the rods are slipping I cranked on all of them and marked them with a marker, they don't move. Each layer is offset by about .5mm. It prints the layer out perfect it just shifts toward the front of the build platform a little every layer. What I don't know understand is its only on large prints and the larger the print it seemsthe larger the shift but its still an even amount every layer. Small prints come out perfect.

[giraffneck 0]

Maybe a clearer way to state it is layer shift.

[gr5 2,266]

Did you mark the motor and pulley around it also? The is the one that slips most often. If you marked the 2 pulleys on the short belt and they didn't slip then it's skipping steps.

The most common cause of skipping steps is when the rubber belt rubs the frame but any friction can cause this. If the rubber belt is lightly touching the frame it's very difficult to detect except that every time the axis changed directions the belt twists the other way. If you see this then add washers or something to get the belt further from the wood frame by roughly .5mm. Or slide the pulley closer to the motor.

Other causes of friction - end caps is the next most common. Try loosening one of the two on each of the 4 rods.

 

[giraffneck 0]

The y axis belt was actually rubbing the frame, I did see the belt twisting and added washers and it didn't change anything. I will try the end caps. That's the only thing I haven't messed with yet Lol. I appreciate your help.

[giraffneck 0]

well, I found it, the top set screw on the short belt was loose, I thought I tightened them all, I must have missed that one (embarrassing). Thank you for your help.