How to calibrate a 3D printer

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You should calibrate your 3D printers from time to time. To compensate for mechanical changes from the last calibration. The calibration ensures that the bed level is horizontal. And the extruder height is one filament diameter above it. So the first layer will stick to the bed. Improper bed position can cause the printer to print in mid-air. Resulting in a long thread of melted filament.

This article will show you the procedure for 3D printer calibration.

 

Ongoing calibration

You should do calibration every once in a while, after changing the bed cover etc.

This process calibrate:

  1. Z extruder rods to be at the same height above the table.
  2. Calibrating the bed so it is horizontal.
  3. Calibrating the extruder height above the bed to be one filament diameter apart.

 

Calibrating the Z extruder rods

This is a simple process. Take a ruler. Measure the height of each rod end. Make sure they are the same. If any skew exists turn manually one Z-motor. So it changes the height of the rod end until both of the rods ends are at the same height.

Using ruler calibrating extruder

 

Calibrating the bed to prevent bed tilt

You want to prevent tilt as it results in a model adhesion problem to the bed. This has bigger effects when you print on the bedsides rather than on the bed center. Recent 3D printers have the ability to measure the bed distances from the extruder at 9 points. The printer log file/Console shows the measurements results.

To perform the bed leveling calibration, sit in front of a Console program connected to the printer. (I use Repetier-Server in a browser). Send the following code to the printer:

G28; Home all axis

G29; Check bed level in 9 points

The command G29 prints information regarding the measured z-points. Try to locate a place on the bed edge that is higher or lower than the other edges. Rotate the bed screw to compensate for this deviation. This might be a little tricky as the screw knobs are below the bed. Remember that rotating the bed screw clockwise raise the bed and rotating anti-clockwise lower it.

Write the results on a graph to see clearly any deviation.

Height graph
Height graph

 

 

Repeat this procedure until you are happy with the results. Leveled bed should show only bed plate imperfections.

3D Printer report
3D Printer report

 

Calibrating the height offset

Calibrating the height of the extruder is important. If the distance is too high above the bed, the extruder will print the first layer in the air. Resulting in an ugly pile of melted filament plastic. If it is too low – the extruder would not emit the first layer at all. The printer would resume normal operation on the second layer. But the model will be stuck to the bed and be hard to peel.

The printer determines the extruder height above the bed. By the “home” height location plus Z-axis offset from the printer flash memory. Here is how to setup the Z-axis offset.

Open the printer monitor (Repetier-Server with a browser in my case) and type:

G28;  Home all access

G1 Z0.3; Move the extruder to the first layer height. (The extruder filament diameter – change this if you have different filament diameter).

Now try to pass a paper between the extruder and the bed. The paper should pass with some friction. Open the printer control panel “Prepare” menu and change the Z-offset according to your test. Higher value means lower extruder. If the paper is not able to pass – lower the value in the console. If the paper moves freely – higher the value in the console.

Repeat this until you are happy with the results.

Select “store values” to keep this value in the printer flash memory.

Calibrated printer results in finer models printed, prevent start printing mess and create a happier owner.

 

 

Another type of calibration suitable for experts wanting to get into a new level of perfection:

Offset calibration

Offset calibration is a specific protocol aim to fine-tune the printer into almost perfection.

It involves commanding the printer to move in a certain axis. Measuring the distance the printer actually moved. And setting this value in the slicer tables. This makes the slicer compensate for movement small variations.

The calibration process can enhance the print quality a little. You can do this calibration once a year if you like to. Just follow the instructions on YouTube or similar resources.

 

 

Happy printing!

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