© 2017 Precision Piezo a trading name of Idris Nowell. 

Universal Kits & Underbed 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.

 

 
Universal Kit Manual can be downloaded here (V2).
Universal kit Manual V1 is here
 

Underbed piezos are placed often in bed mounts containing the piezo discs, which are connected in parallel to an amplifier PCB such as those made by Precision Piezo.

 

Key considerations:

  • That the bed is supported firmly, not balancing on the piezo discs. This is achieved with sliding components which hold the bed well laterally, but allow it to rest on the piezo disc.

  • That the heat from a heated bed is not transferred to the piezo discs. The branded Murata type can tolerate up to 60 deg C, but it's important to tune the Piezo PCB (see here) at the bed temperature you typically print at.

  • The sensitivity will be much higher than with hotend sensors, this is due to having un-drilled piezos (more PZT ceramic present) and having 3 or 4 piezos. This can be a problem as just the inertia of the bed pressing into the piezos can generate a signal as the bed moves.

    • For bed which move in Y, like the I3 and its derivatives, the moving bed is not a problem, as the bed stops and the firmware can be configured to pause momentarily before probing.

    • For beds which move in Z, such as typical corexy's the inertia of the bed moving upwards during the probing move itself can trigger the sensors, which makes this setup a little difficult. Instead, consider using hotend (or carriage mounted) piezo sensors.

  • For heavier beds, it may be preferable to use a design where the piezo disc is squeezed rather than bent, and the use of plastic washers (we are investigating rubber/fibre also) to dampen the response to vibrations caused by leadscrews/belts. This improves the signal to noise ratio and gives a more positive trigger on nozzle contact rather than just reacting to movement/vibration.

  • We are investigating whether using smaller piezo's which generate less signal voltage might also be a good approach for larger beds.