Hotend and print-desk's randomly variable distance
An Observation for Mk2 - 2.5S,+ Owners.
For these machines, the frame of the "Y" axis has an M10 threaded spindle.
The "Y" axis (M10 screw spindles) are supported on the ground at their ends, there are 4 feet of the machine and the sliding bearing shafts are also fixed here on which the print table move.
The Frame of the Machine - which carries the entire structure - and the "X" axis together with the drive and the Hotend are completely fixed on this two threaded shaft approx. in the middle.
Because of the above this, these 2 free treated spindle bend slightly due to the structural weight.
The sliding shafts of the printing table bearing on the other hand are attached to the threaded stem ends.
Therefore, the print table level remains relatively on the legs level.
So of this, the bending of the threaded rods affects the distance "Z" of the nozzle from the print table.
Then if we put the coil filament on top of the frame, it is weight further increases the degree of bending - by definition, depending on the amount of material on the roll. As the filament roll decrease, the weight changes and thus bend of the threaded rods change. This is a very bad variable factor depending on the distance of the nozzle from the print table and the total frame weight.
Proposal:
1.
Do not place the machine on the original feet on the ends of the M10 spindles. Support it as close as possible to the frame at the front - at the back under the threaded spindles - for example, use a wooden pieces of suitable size. Or print special plastic supports.
Thus, the support will not be at the ends of the threaded spindles, the bending force acting on the M10 spindles is significantly reduced.
2.
The filament spool possibly should not be attached to the frame, but independently of the machine frame.
The method worked for me, since then my "Z" distance from the table has been stable.
I hope my comment is useful for the owners of good old Mk2 .. 2.5 etc. machines as well.
🙂