Calibration
How to calibrate the MachineBlocks LEGO® compatible STL generator for a perfect fit.
Original LEGO® bricks are cast from relatively soft ABS plastic to an accuracy of a tenth of a millimeter. 3D printed bricks, on the other hand, are generally harder and have small irregularities or inaccuracies depending on the printer. Depending on the material and the nozzle temperature, the brick also contracts to varying degrees when it cools. In order to achieve a high accuracy of fit, these differences must be compensated for by calibrating the STL generator.
1. Print the Calibration Tool
First, the Calibration Tool must be printed on exactly the same printer with exactly the same filament and with exactly the same temperature settings as the brick that will be printed later.
InformationIf you have problems with printing the calibration tool, check out Troubleshooting
2. Determine knobSize, wallThickness and tubeZSize Parameters
Take several original LEGO® bricks (or compatible bricks from other manufacturers) and test the various test prints on the Calibration Tool on each row from left to right to find the parameters for an ideal fit:
- knobSize - the diameter of the knobs in mm
- wallThickness - the thickness of the walls in mm
- tubeZSize - the diameter of the vertical tubes in mm
AttentionDo not force the original LEGO® bricks onto the Calibration Tool, otherwise the bricks may be damaged. If you need too much force to insert the bricks, select the next smaller setting.
3. Update Default Settings
Once you have found the optimum values for knobSize, wallThickness and tubeZSize, save the values as default settings in the STL generator by clicking on the icon at the top right of this website. If you have installed the STL generator locally using OpenSCAD, you have to manually insert the values into the customizer.
4. Print Calibration Bricks
Now you can print the calibration bricks. Make sure the settings for knobSize, wallThickness and tubeZSize from the previous step have been updated correctly in the Customize pane.
InformationIf you have problems with printing the bricks, check out Troubleshooting
5. Test the Bricks
Now assemble the calibration bricks with original LEGO bricks. If the bricks are too loose or too tight, go back to step 2.
Otherwise, compare the height of the printed brick with original bricks of the same type. If the height differs, you can adjust it with the parameter baseHeightAdjustment.
Finally, place 2 printed bricks next to each other on a plate and examine the gap between the bricks. If the gap is too large or too small, you can adjust it using the baseSideAdjustment parameter.
Adjust Sizing
- baseHeightAdjustment - amount of mm that is added to or subtracted from the calculated height of the brick
- baseSideAdjustment - amount of mm that is added to or subtracted from each side of the brick
