Toolhead offsets are critical to calibrate before attempting any multi-material print, especially if those materials are designed to interact mechanically. A difference of just 0.05mm from the nominal position can cause degradation in print quality and finished part performance.
Calibration should be performed:
- Any time a tool is changed
- Any time a nozzle is changed on an FDM tool
- After any unexpected mechanical loading, such as a tool crash
First, calibrate the tool length (Z-axis) offset of the tool. You can follow the procedure found here: Setting Tool Length Offsets Note that there is far less deviation in tool length with additive tools, so often adjustments can be made visually during a test print.
There are several ways to calibrate X-Y offsets of additive tools:
- Vernier scale
- Concentric rings or other alignment print
- Printing hollow cylinders and probing the center of the cavity
Vernier: Here, you will need to print a vernier scale in both X and Y. You can find both of those factory files available for download below. Adjust the settings so they are appropriate for the materials that you have loaded.
- Print the X-ALIGN file
- For each tool, count the number of gradations from the center to where the gradations align. Each gradation represents an offset of 0.05mm (so in the examples below, both tools are offset 0.35mm)
- In the calibration tab, adjust the tool offset to be the value determined from the vernier scales (if the aligned gradations are to the LEFT of center, you need to move the offset to the RIGHT)
- Repeat for the other tools
- Repeat for the Y-axis
Concentric rings: this is less accurate than the vernier method, but satisfactory for many applications. A sample .factory file can be found below. Make sure that your nozzle sizes and print temperatures are appropriate for your current machine configuration.
Probe a cavity: this method of offset is described in detail here: Setting X and Y Tool Offsets