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 a couple ways to calibrate X-Y offsets of additive tools:
- Concentric rings or other alignment print (See 5.1 Setting up a Simplify3D Process and 5.6 Simplify3D Grouping Processes for creating gcode for the concentric rings)
- Printing hollow cylinders and probing the center of the cavity
Concentric rings: this is the preferred method for additive-only operation. A sample .factory file can be found below. Make sure that your nozzle sizes and print temperatures are appropriate for your current machine configuration. Print the file and manually adjust the offset for each tool using the "Offset" tab of the web control. Iterate until there is no visual offset between tools.
Probe a cavity: this method is necessary if using Hybrid functionality (both additive and subtractive)
This video details how to set XY offsets for subtractive tools. It may be helpful to watch the previous videos in the series, in particular 1.3:
Additive and subtractive tools are not designed to be concentric - this means there is a significant X and Y offset value necessary for Hybrid operations. For additive-only or subtractive-only the effect is less significant, but it is still important to apply accurate tool offsets to produce high-quality parts.
The H-Series includes a Renishaw-style probe, which is capable of probing in any direction, not just vertically. This means you can print or mill a cavity centered at (0,0) in the slicer or CAM software, then use the probe to find the physical center of the printed part, which corresponds to the X,Y offset of the tool. The procedure for this is as follows:
- Ensure that the tool length is properly calibrated for the desired tool. (See 3.2 Setting Tool Length Offsets)
- Grab a piece of scrap stock that is at least 10 mm deep and set up the work space by either:
- Attaching the scrap stock to the additive bed with a piece of double-sided tape, or
- clamping it in a set of standard vice on the dove tail bed.
- Probe the top surface of the stock and set Z in the WCS and switch over to it (example will be using G59.3)
- Swap to the tool to the tool that will be calibrated and jog it down so that it is over the stock and jog the machine down in the Z so that it is approximately 1 mm above the stock
- Clear the current X and Y offsets for the tool and set them to 0.
- Save the X and Y position in the WCS (G59.3 in this example) so that the position now reads 0 for X and Y
- Speed up the spindle to 8000 RPM (See 2.3 How to Control Tools for controlling tools)
- Plunge the tool into the stock by jogging the machine in increments of Z-0.5 mm until the Z position is around -5.0 (This will have created a hole that is approximately 5 mm deep).
- Remove the tool from the stock and bring it up to about Z = 50.0.
- Turn off the spindle.
- Swap to the probe and jog down so that the tip of the stylus is fully inside of the milled cavity.
- Find the center of the cavity.
- Set the X and Y offsets.