(Beta) Piezo UnderBed Mounts by Precision Piezo

thingiverse

These are Delta printer bed mounts to house 20mm Piezo discs. These are beta. My intention was just to try underbed sensors as (apart from FSR's a while back) I have not tried with piezos. And they work, coupled with the Precision Piezo/Moriquendi piezo PCB they are very sensitive. Probably best for smaller beds. Please feel free to adapt them or just use this as a guide to making your own. The idea is the piezo is supported around the edges, the weight of the bed presses the upper part lug into the centre of the piezo. Instruction for the bed mounts. Print them in ABS as accurately as possible. There are some tolerances built in. Each mount has 3 parts. The base is the lower part shown in the diagram. It has a 5.5mm recess/3.5mm hole this is for an m3 screw to hold the mount to your printer attach it. You might need to alter this hole to suit your printer, I modelled my bed/printer in CAD to ensure it fits. Make sure the screw head sits in the recess. Insert a 20mm piezo disc, and pass the leads out through the small hole. The next part shown in the diagram is in the middle. The upper part the bed mount has a lug which goes through this middle part. Tolerances here are tricky to achieve without adjusting, so take a fine warding file and file the hole in the middle part until the upper part lug can pass through with a fairly tight fit. The middle part has a cut out for the solder pad on a Murata 20mm piezo disc, you might need to alter this to ensure it does not sit on the solder of the piezo disc. Place it over the piezo disc, it should not press onto the disc, but be supported around its circumference. Bond it with superglue to the lower part. Insert the top part. Now repeat for the other two units. The piezo leads need to be connected to a piezo amplifier, available at http://www.precisionpiezo.co.uk/shop and tuned. Shown in the second photo above. They should work for 27mm piezo's just scale them so that a 27mm piezo fits in instead. If the piezo probes badly when hot but well when cold, then you might need to add some cork insulation to the mounts to keep heat from the bed away from the piezos. Future release might include some clamps on the top parts.