Ultimaker printhead with optical table-level auto-calibration sensor and servo

thingiverse

One day, I decided to create an automatic table calibration system for my Ultimaker plywood. Various sensors, including inductive, piezo, tenzo, and others, were not suitable because they either took up valuable workspace or caused problems with the installation of cooling fans for the printed part. This also applied to BL-Touch, and its clones, whose quality and reliability had recently left much to be desired. As I learned from experience, optical limit switches are the best solution for implementing precision positioning tools. Based on this knowledge, it was decided to design a sensor for automatic calibration of the table level. The principle of operation of this device is similar to that of the same BL-Touch. However, the sensor uses an optical limit switch instead of a Hall sensor and a servo drive instead of a retracting solenoid. Thanks to its long probe, the entire device was able to be placed on top of the print head. I used a bicycle spoke as the probe, shortening the thread to 5 mm and making the length of the entire probe 80 mm. Two Volcano nozzles served as guides for the probe, with holes drilled up to 2 ... 2.2 mm. You can use outdated nozzles or do without them altogether. The archive contains a printhead housing file with holes without thread - U5_AUTO_LEVEL_E3D_HOLDER_NO_NOZZLE. Probe Offsets: X=20 mm, Y=0 mm, Z=-2 ... -1.5 mm (experimentally selected). P.S. For adequate operation, it is strongly recommended that you solder two capacitors into a wire break directly near the servo. Electrolytic 100 µF should be placed between the positive (red) and negative (brown) wires, while ceramic 0.1 µF should be placed between the signal (orange) and negative (brown) wires. This will eliminate interference. It is also necessary to power the servo from a separate DC-DC converter after setting 5 Volt on its output. This will offload the 5 Volt bus on the 3D printer board. https://www.youtube.com/watch?v=dzim4jhBjuY https://www.youtube.com/watch?v=yESJPz21lvs https://www.youtube.com/watch?v=xsbyDk3j1VI