How to calibrate the nozzle height (Z-offset)
The Z-offset is the distance between the tip of the nozzle and the bed when the Z-axis is at zero. Once set correctly, it only needs tweaking when you change the build surface, nozzle, or material.
What the failure looks like
Not a fault as such: it is the setting that determines bed adhesion, elephant's foot, bottom surface finish, and a good deal of your tolerances.
Causes, most likely first
- 01
Build sheet or surface change
Every build sheet has a different thickness; the offset changes.
- 02
Nozzle change
When fitting a new nozzle, it rarely sits at exactly the same height.
- 03
Bumps or transport
Moving the machine around often knocks the sensor out of alignment.
Step-by-step fix
1. Heat to working temperature
Set the nozzle and bed to the required material temperatures. Cold levelling is useless.
2. Clean the tip
Any residual plastic stuck to the nozzle will skew the measurement.
3. Paper method (rough estimate)
A sheet of 80 g paper is about 0.1 mm thick. It should slide between nozzle and bed with slight resistance.
4. Fine-tuning while printing
Print a 100 x 100 mm single-layer square. Using babystepping, lower in 0.02 mm increments until the lines touch without overlapping.
5. Read the result
Separated lines with gaps = too high. Translucent surface with ridges = too low. Smooth, uniform surface = spot on.
6. Save the value
Note it down per surface and material; it saves half an hour every time you switch.
So it doesn't happen again
- Repeat the first layer test whenever you change the build sheet or nozzle.
- Note down the offset for each combination on a label attached to the printer itself.
Related questions
How often do you need to relevel?
With a stable magnetic bed and ABL, every 20-30 hours or after moving the machine. Without ABL, once a week if you print daily.
Keep reading
What if it isn't worth your time?
Sometimes the part is more urgent than the learning curve. We're a workshop in Viladecavalls: send us the file and we'll print it with the right material and settings.
Still not working?
Tell Marco which printer and material you use and he'll tell you what to change.
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