Hotend hitting print

Hi,

Having problems with my MakerFarm Prusa i3 when I print the hotend hits the print which makes the x axis move out of alignment. I have checked and my steps per mm is set correctly to 4000. And if I print a 20mm cube the end height when I measure it was 20.30mm so that is good. I have tried printing at different speeds and all but in the end it hits and stuffs the print.

Currently I am using the latest Marlin firmware, pronterface and KISSlicer. I have also tried Silc3r. I am printing with 1.75 ABS filament, tried 0.25, 0.252 & 0.3 layers.

Any suggests what else to look at or try?

Thanks
Tim

hi,
take it it only happens when crossing the print??, if that the case then find the setting in slicer where you lift the Z axis by .5 while traveling across the print..

Some posible causes:

• Bed height not calibrated well: The distance from the bed has to be the same, wherever the hot end is. It also has to be close enough for the plastic to stick well.
• Warping a bit, any sign of detaching off the bed? One way to avoid warping is to make sure it is stuck to the bed. If you're printing on glass, window/glass cleaner or acetone can help if it is dirty.
• Overextrusion plus time enough to cool also sounds plausible.

Thanks both for the ideas.

@Jinx While yes it is only when it crosses the print, not sure that setting would help unless I also put a anti-backlash mod on the z axis first. Once I can print reliably I was going to do this.

@ Jasper

• I normally check and re-level the bed most prints and I think I have it nice and level
• I have no troubles with the print sticking to the bed. Even when it gets hit it doesn't lift/move.
• Possible, I will play with the extrusion a bit and see if that helps.

Note, the sticking to the bed only prevents warping when it mechanically able to do it.(I have always used PLA so far, so not that much experience with warping.