Glossary
Build plate: The sheet of material which forms the top layer of the print bed.
Print Bed: The surface onto which the print is built, layer by layer.
Print head: Mobile housing that contains extruders, the nozzle and the feeder in the case of the Prusa Mk3.
Nozzle: The small tip with a hole through which melted plastic is pushed onto the build plate. These come in various sizes.
When do you need to do a first layer calibration?
The Prusa MK3S+ does not innately know where its build plate is, relative to its nozzle. Before each print the Prusa performs an automatic levelling (to ensure each part of the plate is the same distance away from the nozzle), however the "Z Adjust" setting allows us to manually set the distance between the tip of the nozzle and the build plate.
The correct "Z Adjust" is determined by performing a first layer calibration - this is where the printing prints an example first layer for testing purposes and we adjust the height of the nozzle as it does so.
The Prusa uses metal build plates but these can be displaced, warped, dirtied or damaged over time and so occasionally may need 'levelling' - which tries to ensure the nozzle is an equal distance form the build plate at all times.
If you find that you are having trouble with your print not sticking to the print bed or under-extrusion during the first layer of printing you may be able to resolve the issue by performing a first layer calibration.
First Layer Calibration
- Ensure the build plate is clean (remove any debris) and also the tips of the nozzle (use pliers to remove any debris from the tips of the nozzle, be careful not to damage them, do not touch the nozzle with your hands).
- Use the button wheel to select Placeholder >use existing z height
- The printer will now take a few minutes to heat up before printing. When it begins you can use the while to increase (+) or decrease (-) the distance between the nozzle and the build plate.
- If you can see that the material is not being flattened against the build plate or is coming off the surface (look at the corners of the path and the extremities of the print especially) then reduce the distance.
- If the material is transparent or is not coming out due to being too close to the build plate then increase the distance.
- Seek staff advice if you are unsure
- When finished, clean the build plate and recycle the material.