Materia 101: Do's And Don'ts

1. Don't use the wrong layer heights

There is more or less suitable layer height for Materia 101. The maximum layer height possible is 80% of the nozzle size. The Materia’s nozzle size is 0.35 mm, hence we get a maximum layer height of 0.26 mm. However certain layer heights are not good to use, this is due to limitations from:

• the lead screw - The threading on the lead screw connected to the z axis motor.

• the stepper motor -Steps per revolution of the stepper motors.

• the stepper driver - The number of microsteps.

We can calculate total number of microsteps as below :

Total number of microsteps = Steps per revolution x No. of microsteps

= 200 x 16

= 3200 microsteps

Now we use this value to calculate the vertical “resolution”. The threaded rod moves the z carriage 8 mm per revolution, thus 8000 micron / 3200 microsteps = 2.5 micron*, ie. 0.0025 mm. Valid layer heights must be multiples of this value, such as:

Valid Layer heights (mm)       Number of steps and microsteps
0.04 			       1 step 		 		 	
0.06 			       1 step, 8 microsteps 		 		 
0.08 			       2 steps 		 		 		
0.1 	   	               2 steps 		 		 		
0.12 			       3 steps 		 		 		
0.16 			       4 steps 		 		 		
0.2 			       5 steps 		 		 		
0.24 			       6 steps  

*a micron (aka. micrometer) is 0.001 mm

NOTE: This 0.0025 mm is the theoretical limit of your machine, since it is the length of one microstep of the motor, however this is not usable in reality. You can probably use a layer height down to 0.08 mm, if your machine is well calibrated. Note that lower layer height take much longer to print.

2. Don’t overshoot the maximum print size

Make sure your object/model does not exceed the print area, which has a size of: 140x100x100 mm (X, Y & Z).

Tip: Move the binder clips  to adjust for the object you are printing. This way you can build bigger objects on the small build area without the nozzle crashing into the binder clips. 

3. Don’t leave the extruder heated

PLA might burn if exposed to long periods of high temperatures. If you heat up your nozzle to change filament or print something and you don’t have a print job to print immediately after, turn off the heat. Burning PLA in the heated extruder will quickly degrade it and cause black residue inside the heated chamber. If you are lucky, the black gummy residue will be expelled from the nozzle and merely spoil your prints, but if the burnt residue has bigger, more solid particles, they might block the nozzle.

4. Do: Have the right tension on the Extruder idler

There are 4 bolts (with springs) on the extruder, these hold the extruder idler in place and push the filament against the hobbed drive gear.

Make sure these bolts are tight enough so that the motor misses steps and make a clicking sound if you hold and stop the filament from being pulled into the extruder.

If the tension on the idler is loose when you print, you’ll get the same symptoms as if you are printing at a too low temperature, i.e. the printer will not extrude enough plastic.

5. ​ Do: Have a level bed

​Remember to level the bed with the inbuilt leveling routine found in the prepare menu. Using a skirt on every print is also a good idea.

6. Do: Use hairspray in the correct manner

If you use hairspray on the print surface, avoid getting it in the sensitive mechanics of the machine by removing the glass print surface before applying it. Hairspray should be regularly removed from the glass plate when it shows a significant buildup or is worn out. Wash the plate with lukewarm water to remove the hairspray.

Here is a video of the correct way of applying hairspray.

7. Do: Place the filament spool correctly

The recommended position is behind the printer, on the same level as the printer. There can be alternative positions, like if there is a wall or a shelf near the machine. The important thing is that the plastic wire should be easily fed into the extruder without tangling or adding friction.

8. Do: Measure the thickness of the filament.

On the spool it might say 1.75 mm but it can vary both up and down. Use a caliper to take 4-5 measurements on a length of 1 meter of filament. Add the results and divide it by the number of measurement to get an average.

9. Do: Keep the nozzle clean

PLA sticks quite well on brass, but sticks a lot better on PLA itself. If you keep your nozzle tip clean, it will lay down the layers properly. If you let PLA to build up on the nozzle tip, it will stick to your print and weave little strings or spoil the structure of your layers.

To clean it heat up the extruder to normal printing temperature, and use a paper towel or a piece of cotton fabric (avoid synthetic fiber). Lower the bed so that you can reach the extruder tip and swipe the towel onto the nozzle, avoid direct skin contact with the tip itself. Use either tongs or thick gloves to avoid burns.

Here is a video of me cleaning the nozzle

10. Do: Keep the drive gear in the extruder clean

There are certain situations where the “hobbed” gear might slip and dig into the plastic filament:

• The temperature is too low for the printing speed.

• The fan is turned off and the heat makes the filament cool near the feeding mechanism.

To clean the hobbed gear you need to unscrew the idler.