TAZ z-axis grinding at start of print

I recently inherited responsibility for a TAZ printer at my workplace. It has been in operation for a couple of years, however the person who used to operate it no longer works here, so I am having to learn on my own.

It’s been going pretty well so far, except that occasionally when I press Print in Cura, when it tries to move upwards on the z-axis in order to re-adjust the position on the bed, rather than moving it just makes a grinding noise, then proceeds to move across and downwards, causing the hot end to gouge into the bed. Luckily I have always intercepted it before it does any real damage.

This is frustrating because it means I have to cancel and re-start the print, sometimes several times, before it works properly. I know it’s not something simple like a jammed z-axis screw, because it works properly sometimes, and when I move the z-axis up and down using printrun it responds perfectly. This problem also sometimes causes the x-axis bars (sorry I don’t know the proper terminology!) to become skewed, and need re-leveling, which makes me think it is a problem with just one of the z-axis screws.

Thanks so much for any insight!

When it does the home function which is what you see at the first. It moves at a faster rate than when using the manual movement buttons. So the Z axis binds because it creates more friction doing this fast movement. So you need to release the tension of the X axis belt and release the twist on the Z axis the X axis has on the Z lead screws by loosening the set screws on both X rods and finding the point the rods will set loosely on the rods then tighten them back down and then tighten the X axis belt back to proper tension again.

You have a very slight pull inwards/outwards on one side that is applying too much pressure to one of the smooth rods by the Igus bearing. I have seen a couple printers with this issue before. :nerd: