Z Probe Options

MrAwesome987

Hello,

I am working on a custom coreXY and would like some advice on what Z probe method to use.

My goal with this printer is a very lightweight carriage, hopefully capable of fast printing.

I am going to use an E3D Roto Standard. I have a Duet 2 Wifi currently but would not be opposed to getting something different if necessary.

On other printers I have used the BLTouch with success, but I would like to reduce weight/bulkiness if possible.

I have been looking into using a piezo disc, but I am not sure how to incorporate it with the Roto.

What lightweight options are there? I am not against customizing something to fit my needs, but an "out of the box" solution would be great too.

Thanks for the help!

Notepad

@MrAwesome987 If you have access to a CNC lathe, I would recommend making an adaptor to go from roto/hemera heartbreak to Voron mounting plate.
That way you can use the E3D probe on any voron style heat block

Alternatively you could look at putting Piezo disks under the bed, or having some form of tap/rtap plate

I personally would stick away from inductive probes and BLtouches nowadays as alternative solutions give perfect nozzle probing. otherwise a good M12 sized inductive probe is a fool proof solution.

MrAwesome987

@Notepad said in Z Probe Options:

Alternatively you could look at putting Piezo disks under the bed, or having some form of tap/rtap plate

You mention putting the piezo under the bed... (Really showing my ignorance here...) How would that work? Do I need more than one?

I am planning to mount the bed using a Maxwell mount. Could I place a piezo disk under one point, or would I need one under each contact point (3)?

Notepad

@MrAwesome987 said in Z Probe Options:

You mention putting the piezo under the bed... (Really showing my ignorance here...) How would that work? Do I need more than one?

You would only need one, but if money was no option, having one under each mount point could give a level of redundancy.

The way piezo disks work is they translate crushing force into a analog voltage output, so as long as when the nozzle taps the bed, the force can be pushed through the peizo disk, then it should sense.

I had a version that used it but unfortunately my bed mounting was too dampened with silicone spacers so it didn't have enough impulse to reliable sense the force.
For reference, Bambulabs P1 series has a peizo (its actually a load cell so technically different but works similarly) for their nozzle probing.

MrAwesome987

@Notepad Ok, given that information...

Let's say I use the Precision Piezo kit, how do all 3 work at the same time? Does it take an average of the 3 or something? It appears to only connect to one limit switch on the Duet?

What are the disadvantages to using piezo sensors, especially under the bed?

Really appreciate your help!

Notepad

@MrAwesome987
The advantage of having 3 sensors is you can have a redundant setup. if you set the sensitivity too low, then the sensor might not activate. by having multiple, you only need a single one to activate to tell the printer that the bed/nozzle has homed.

The downside of the sensors is they can be a bit of a hassle to set up, as if you set them to be too sensitive, they could also pick up vibrations from other sources (like someone dropping a heavy object on a suspended floor)

dc42

@MrAwesome987 E3D has a piezo made specifically for the Roto now, see https://e3d-online.com/products/pz-probe.

MrAwesome987

@Notepad I mentioned planning to use the Maxwell mount for the bed... The bed will be moving along the Z axis, not the gantry. Will the Piezos still work for Z probing in this way? IE, the bed will be moving up to touch the nozzle.

MrAwesome987

@dc42 said in Z Probe Options:

@MrAwesome987 E3D has a piezo made specifically for the Roto now, see https://e3d-online.com/products/pz-probe.

I have looked into this, but can't see how it would work with the Roto standard? Maybe I am missing something? It appears to be designed to only work using a Voron cold side, but they make it available to be used for custom applications:

Notepad

@MrAwesome987 Unfortunately I havent seen any mount to go direct from E3D PZ coldside kit to Roto. For me Im using the PZ disk on its own and then making my own adaptor mount