Calibrations are a standard part of keeping your 3D Printer running properly. The Heads Filling Calibration is no exception. While this particular calibration is not needed very often, it can be useful to keep part quality at its best. For all of the small J printers from Stratasys: including the J35, J55, J5 Medijet, and J5 Dentajet. If you have any questions please reach out to our customer support team at GoEngineer.com and we will be happy to help you.