Shortly after I saw machine hours a bit above 900 I decided it was time for a check-up with careful attention to fastener tightness.
After flawless prints, pieces began to “fall over” with about 3 cm high. I literally heard a rough grating sound as the print head crossed newly laid infill.
The situation worsened–rapidly and there was an increasing amount of PVA “snow” on the build table. I watched to see the machine catch a piece to topple it.
The first screw I touched was the upper right Z-axis screw circled in green and easily visible with the machine fully assembled and table in any position. It turned more than three complete rotations before becoming snug!!!
I laid the machine over to tighten all of the screws on the bottom of the fully assembled machine. Many were firm, a few were not snug enough and two that were roughly across the machine from the upper screw that was so loose were also very loose requiring two or more turns each.
I then went to the green circled screws revealed by removing the access door beneath the table. At least four required tightening. I then returned to the bottom of the machine to ensure everything was still tight and guess what? Two required snugging. Back upright at least three of the green circled screws required snugging. I returned to the bottom for a third time to find everything tight.
The print head found all screws firm save the one 1.5 mm one in the front, lower-right which required only very light snugging. Everything behind the rear access panel of the print head was nice and snug as were the easily accessed screws in the X-axis motor drive/lamp unit at the right.
The only other loose screw was in the extruded filament cutter assembly on the left–specifically the factory screw holding the metal sub-assembly to the plastic body. The assembly mounting fastener was fine.