Hotend Piezo Sensors
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You are however very welcome here on our GENUINE website, please also consider purchasing our GENUINE product direct from us in our shop.
Piezo 20 Module STL's are available on Thingiverse.
Piezo 20 PCB Step file to help you integrate this into your possible design.
The important factors in hotend piezo systems are:
A piezo with a hole drilled into it. Video of how to drill piezo. This allows the filament to pass through the piezo, enabling the force generated by nozzle contact with the bed to transmit to the disc for sensing.
That the most effective way to use the disc is to support it on its circumference and then press up into the centre with a collar-shaped part attached to the hotend. See the piezo 20 design as an example.
Relief needs to be included in the design for the solder pads on the piezo disc. This prevents erratic operation and protects the solder joints. Allow the piezo leads some freedom to move but not to get snagged or pulled.
Larger Piezos contain more piezo-electric ceramic and give more sensitivity, they also bend more, but the resulting assembly is larger and may be more compliant, which might be a problem with nozzle stability. Smaller discs exhibit the inverse properties. We are limited to 20mm (although 16mm might work) with hotends, as a 4.5mm (minimum) hole is needed for the filament to pass through.
Any assembly of this type is an optimisation exercise between a very sensitive unit with a wobbly hotend and a less sensitive unit with a firm hotend.
Typically with the right mechanical design, a well-tuned PCB (we can only speak for our design here), and the correct settings in firmware accuracy of 10 microns can be achieved, with repeatability std deviation of 7 microns. To put this in context a first layer is often between 200-300 microns thick. Probing force need only be 5-15g. Further work is ongoing to reduce this even further.