X and Y axis shift problem - Solved

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ge_rik
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X and Y axis shift problem - Solved

Post by ge_rik » Tue Dec 29, 2020 2:10 pm

This is what I was trying to print
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It's quite a large piece (190mm x 84mm) taking nearly 13 hours to print and so the bed needed to be absolutely level to ensure it would stick. However, after about seven hours of printing, this is what I found.....
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The Y axis had shifted towards the front of the machine by 21mm.
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I aborted the print and when returning the bed and print head to their home positions, got the most appalling sounds. Closer inspection revealed that two of the bed adjustment knobs had unscrewed themselves completely and were impeding the movement of the bed.

I screwed them back into place and levelled the bed. However, the knobs were still quite loose on their threads - ie the bed was as high as the springs would allow. So I gave the two worst offenders an extra half turn so they wouldn't work loose.

I set the printer off again and then, ten hours later was greeted by this .....
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The X-axis had shifted to the left by about 80mm. On closer examination, I noticed it had also shifted to the right by about 4mm prior to this.
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The bed adjusters were still fine and so I looked elsewhere. I then noticed that the upper left corner of the part had curled upwards away from the bed and so figured that the print head had caught on it and the belt had slipped (twice!).
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Checking the bed level again, I found that that particular corner was too low - I had over-tightened the bed adjustment knob a fraction too much. However, this meant the knob was now too loose again. On my cheapo printer, I could simply have lowered the Z limit switch a few mm but my more expensive printer had no adjuster for the Z axis switch (They say it's to make it less complicated for novices to set up the printer!!). A quick search revealed there was part on Thingiverse which would allow me to adjust the Z axis limit switch. It's been downloaded 200 times and so it would appear I'm not the only one to feel the need to adjust the Z-switch!
Z axis adjuster.jpg
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Unfortunately, it needs four bolts to hold it in place, whereas (no doubt as a cost saving exercise) my printer only came with two bolts on the original piece. I've sent off for more bolts but in the meantime I've found a temporary solution. I've raised the bed a few mm by putting washers under the springs. I can now tighten the adjuster knobs so they are no longer loose. Not the most elegant solution, but it works!!

Rik
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