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3D Printing Calibration

This section describes how to measure and set the Calibration Offset used in the 3D Printing workflow. This is necessary for accurate printing as the system might feature small inaccuracies such as due to a freshly mounted probe.

This workflow prints a simple structure and allows the user to align the preview of the structure with the actually printed structure. The difference in position is the Calibration Offset. Applying the Calibration Offset in future print runs leads to accurately positioned print structures.

1. Prerequisites

2. Performing the calibration

Enter the 3D Printing Calibration workflow.

Screenshot

  1. Set the right print parameters
  2. Add the calibration print file to the task list
  3. Start printing
  4. Measure the Calibration Offset

You also have the option to measure the offset of an already printed structure. Simply add the print file of the printed structure to the list.

  1. Add the already printed print file to the task list
  2. Measure the Calibration Offset

Optional

Time out
If the printing process comes to a halt, the system waits this specified amount of time before executing the Time out action.
Time out action
The action to execute when the printing process reaches a time out. You can choose one of the following actions:
  • Abort the whole printing process
  • Pause the printing process
  • Cancel the current print structure and continue with the next one
  • Cancel the current print structure and pause the printing process
Use transformation
Apply a transformation (translation and rotation) to each file that is printed. In combination with Preview, this allows you to place a print file at a specific position.
Preview
Select one or multiple print files and click the preview button to display a preview of the structures at the XY position specified in the print file using the top view camera.
Move to start position
Moves the top view camera to the start position of the currently selected file.
Move to chamber center
Moves the top view to the center of the printing chamber. This usually corresponds to the center of the substrate.

Clicking on Print Params will open the Print Configuration dialog where the printing parameters can be set. The default values are loaded every time the software is started.

This is the Print Configuration dialog:

Screenshot

Voxel Detection Threshold
The cantilever deflection setpoint that defines voxel completion. The setpoint is relative. Recommended is 0.4 mV up to 200 mbar. Above 200 mbar 1 mV is recommended.
Setpoint Detection Window
The amount of sample points used for threshold detection of the cantilever deflection signal. The first sample of the window is subtracted from the last sample of the window. If the result exceeds the voxel detection threshold, a voxel completed event is triggered. It is recommended to use the LogViewer and analyze the deflection data to find a correct window size.
Initial Approach Speed
The approach speed of the cantilever at the start of the printing run. Maximum recommended speed is 20 µm/s.
Approach Detection Threshold
The cantilever deflection setpoint in Volts that has to be reached when the system first approaches the sample before printing. The tip will approach the sample at (X0, Y0). If the Approach Detection Threshold has been reached, the software defines the current z-position as Z0.
Initial Retract Height
After the tip has reached the substrate surface at (X0, Y0, Z0) it retracts the distance specified here and continues to the first voxel location at (X1, Y1) travelling at the defined height above the substrate surface.
Record Log Files
Set to yes to store the deflection signal (in Volts) to a .txt file. Print parameters and detected voxels are written to different files even when this parameter is set to no.
Print Retract Distance
To avoid collisions when moving from one print structure to the next one, this distance is added to the currently defined content height when moving to the start position of the next print structure.
Safety Retract Distance
The distance to retract after a print structure has been printed. This helps to mitigate collisions with already printed structures.
Wait Time Before Approach
The time to wait after 0 mbar has been applied but before the approach starts. This prevents false deflection detections as the tip might still oscillate during the approach if no wait time is used.

4. Add files

Clicking on Add Files... opens up a file selection dialog. You can add only a single file.

Clicking on the graph icon on the right of the file name tag gives a 3D visualization of the voxels in the print file.

5. Start printing

Print file or directly measure offset

Clicking OK will give you the option to print the file or just use it as a basis to measure the Calibration Offset.

Click Print to print the calibration structure before measuring its offset.

6. Measure the calibration offset

Measure offset options

After successfully printing a calibration structure, the workflow shows you the option to measure the calibration workflow.

Since you can perform the calibration multiple times, past measured Calibration Offsets are shown. The new offsets is calculated based on the old offset since the calibration structure was printed with the previous calibration offset.

The following interactions are now possible:

Reset calibrated offset
Resets the previously stored calibration offset to (0, 0). Use this action with caution as the just printed structure was printed with the previous calibration offset. Resetting the Calibration Offset can lead to inaccurate measurements.
Move to start position
Moves the top camera above the theoretical start position of the provided calibration print file.
Show start position
Displays the theoretical start position of the calibration print file on the video feed.
Show circle
Shows a circle in the center of the video feed for easier alignment with the printed structure.
Circle size (inner diameter)
Changes the diameter of the circle on the video feed.

To measure the offset, perform the following steps:

  1. Click on Move to start position
  2. Activate the Show circle option for easier positioning
  3. Drag on the video feed to align the center of the video feed on the structure Measure offset
  4. Click Save offset

The measured Calibration Offset will be automatically applied to all future print runs.

7. Log Files

The 3D Printing Calibration workflow outputs the same log files as the 3D Printing workflow.