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Makerspace Staff Guide: Equipment Maintenance

Covers routine maintenance for makerspace equipment.

Monthly Maintenance

From the Prusa Website:

  • Smooth rods: scratches/grooves - take each rod between two/three fingers and move them slowly from one end of the rod to another, while rotating the fingers around the rod. If you notice any scratch, verify it with your fingernail. 
  • Smooth rods and Bearings: Clean the smooth rods with a clean paper towel, and lubricate them using a small amount of Prusa Lubricant.
    Only in case you feel the axis is not running smoothly anymore even after recently cleaning and lubricating the smooth rods, bearings can be taken out, cleaned with alcohol, and greased on the inside, still using a small amount of Prusa Lubricant. 
  • Belt pulleys: any debris around the belt pulleys and belts should be immediately removed to ensure smooth operations. Also, check if the set screw of the belt pulley is firmly secured on the flat side of the motor shaft.
  • Belts: Both of the belts should be tight enough to sound like a low bass note when plucked. 

If you find the belt tension insufficient when conducting the axes check, adjust belt tension according to the following procedures:

Removing the Printer from the Enclosure:

Adjusting belt tension can be very difficult with the printer still located inside the enclosure. Removing the printer will make the job much easier.

  1. Remove the filament if loaded
  2. Remove the spool mounting pin by rotating it and pulling it to the left
  3. Unplug the main power supply
  4. Unplug the ethernet cable from the back of the printer

  1. Unplug the two cables running to the LCD screen and pull them back up inside the enclosure (if mounted outside the enclosure)

  1. Rotate the mounting pins for the PSU so that it can be removed

  1. Using the handle, slide the PSU off the mounting pins and pull it through the opening in the plexiglass.

  1. Place the PSU on the magnetic bed to keep it somewhat secure and lift the printer out of the enclosure.

X Axis Belt (From the Prusa Website)

Slight Adjustments

  1. Slightly release all the screws holding the motor, otherwise, the "tensioner" won't work as the motor must be able to move (left picture).
  2. Using the ball end of the Allen key, start tightening the screw on the rear side of the X-end-motor, but after each turn or two check the tension in the belt (right picture).
  3. When you achieve optimal tension, please tighten the screws again (left picture). 

 Large Adjustments

  1. Loosen the three indicated screws covering the X-carriage. Carefully take out the X-cover-back.

  2. You now have access to where you mount the belt. Put a mark on the belt with a pen or marker as close to the plastic part as possible, so you know how it was adjusted. Now, take out the belt from the mount and move it in 1-2 teeth.

Y Axis Belt

Slight Adjustment

On the front plate of the printer's frame, behind the LCD module, you will find the printed Y-axis belt idler. This is held by two M3X10 screws (purple arrow), going through the front plate.

If you have a gap between the idler part and the front plate of the frame (blue arrows) you can tighten the belt by using your 2.5 mm Allen key to turn the screws clockwise (purple arrow), closing the gap.

The easiest way to access the screws is from below, by moving the printer to the edge of its table, with the LCD module sticking out. You now have access to the bolts from below the LCD module.

Large adjustments

The Original Prusa MK4 has a different design than in the pictures, but the procedure is the same. 
  1. Unplug the printer and lay it over on the side of the PSU.
  2. Below the bed carriage, you will find the belt holder. Loosen the right screw by turning it counterclockwise (orange circle left picture).
  3. Turn the screw going through the two halves of the belt holder (purple arrow right picture). Turn clockwise to tighten the belt, moving the two halves together (blue arrows).
  4. When at the correct tension, secure the right half of the belt holder again by turning the screw from step 2 clockwise (orange circle left picture).
   

From the Prusa Website:

The RPM (revolutions per minute) of both fans is constantly measured. This means that the printer will report an error if the fan suddenly slows down, for example, due to a piece of filament stuck in it.

In such a case, check and remove any dirt from the relevant fan. Do not try to bypass the RPM check, as this could damage the printer!

Both fans should be checked and cleaned after every few hundred hours of printing. Dust can be removed with compressed air in a spray can, small plastic threads can be removed with tweezers. 

Do not blow compressed air on the running fan.

When accessing the extruder parts, avoid opening the gearbox, unless our official technical support asks for it. In case you need to open the gearbox, make sure that you have the Assembly Adapter printed so it can be re-assembled correctly.

The primary gear and the bearings attached to the Idler Shaft in the extruder do not need any lubricant. Over time, a deposit of filament debris can form in the grooves of the primary gear, which then causes insufficient filament extrusion. Access the extruder by lifting the Idler Nut, and then moving the Idler Shaft. You can blow away the dirt with compressed air, or use a brass brush or an ordinary toothpick. Use the access hole on the side of the extruder.