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Nozzle Offset

Now we need to tell OpenPnP how far the nozzles are away from the center point of the top camera. There are multiple strategies you can use to calculate this. One way is to use OpenPnP's built in Offset Wizard. You can read the OpenPnP docs about this step here.

See also our setup video.


OpenPnP has some new methods of calibration using a secondary fiducial at a different Z height, and a small piece of paper. If you'd like to explore this method of calibration, you can find the OpenPnP docs about this process here. This process requires making and installing a calibration rig, 3D Units per Pixel calibration, and Advanced Camera Calibration.

  1. Ensure you still have an N045 nozzle on the left toolhead. Install the N045 nozzle

  2. Click on the Machine Setup tab in the top right pane. Machine Setup Tab

  3. Click on the "Expand" checkbox to open all of the features about your machine. Expanding the Machine Config options

  4. Click on Heads > ReferenceHead H1 > Nozzles > ReferenceNozzle N1 Open the Nozzle N1 settings

  5. Click on the Offset Wizard tab. Offset wizard settings

  6. Confirm that the Include Z? checkbox is unchecked. do not use the include z checkbox

  7. Read the instructions that OpenPnP provides in this window. This guide will use the homing fiducial as the starting point, instead of using putty or flour. Those are valid strategies as well if you'd prefer them.

  8. Select the Nozzle: N1 from the machine controls dropdown. Select nozzle from machine control dropdown

  9. Jog the nozzle so that it is just barely touching the datum board, and perfectly centered over the homing fiducial. We recommend looking for the shiny edge of the gold fiducial poking out from under the nozzle tip to determine if you've centered it correctly. Jog controls Nozzle almost touching homing fiducial Nozzle touching the homing fiducial

  10. Click Store nozzle mark position. Do not navigate away from this configuration page while running the wizard. Store the nozzle's position

  11. Raise the nozzle off the datum board. raise the z-axis

  12. Jog the X and Y axes to bring the top camera directly centered over the homing fiducial. Again, do not switch away from the Offset Wizard tab, as OpenPnP will not save your nozzle mark position. bring the top camera over the homing fiducial

  13. After centering the homing fiducial in the top camera view, click Calculate nozzle offset. calculate the nozzle offset

  14. Click Apply to save the nozzle offset change. click the apply button

  15. Start again from step 1 to calibrate your right nozzle. Use the Heads > ReferenceHead H1 > Nozzles > ReferenceNozzle N2 section.

Further Adjustment

If you find that your placement accuracy is slightly incorrect after performing this calibration, you can fine-tune your part placement by adjusting the X and Y offsets in the relevant nozzle settings, as shown below. nozzle offsets

Next Steps

Next is Bottom Camera Position.