Piezo self-levelling sensor for 3D printers - instead of BL-Touch

Hello to all 3D printing enthusiasts.





Recently, 3D printers have become more widespread, which is very positive given their advantages.
However, nothing comes without pain.

Have you had problems with insufficient adhesion of the first print layer, resulting in its deformation?
Have you had problems with the nozzle-to-table distance compensation when printing the first layer?
Do you get tired of having to carry out the "paper test" over and over again with minimal changes to the head geometry?
Do you get tired of having to determine the distance of the level probe from the nozzle tip after each replacement or repositioning of a clogged nozzle?
Aren't you tired of the constant "knocking" of the level probe's extendable and retractable pin?
Haven't you noticed that almost all samplers have a repeatability of 15 to 25 microns, not to mention thermal drift?
Have you not had to replace a sampler due to loss of precision caused by mechanical wear or damage?

If you answer yes to any of the above questions, then you will probably be interested in a sensor solution,
that relieves you of all these problems.

You have probably already seen many 'mods' of 3D printers by their owners.
Most often, the mechanics, control electronics or operating system are modified, but rarely does the subject of modifying the level sampler come up.
There are many different samplers on the market, but BLTouch samplers or close clones of these dominate.
Inductive, capacitive and mechanical sensors are also available.
A separate group of samplers are piezoelectric samplers,
however, in all the solutions I am familiar with, far-reaching modifications to the head are required to install such a sampler.
This is obviously cumbersome and sometimes requires considerable skill in "handiwork",
hence the low popularity of such solutions, which is a pity, since a properly installed piezo sampler frees the user from the pains indicated in the questions at the beginning of the post.
Of course, apart from the advantages, piezo samplers also have disadvantages. One of them is the need to keep both the nozzle and the table perfectly clean,
so that filament residues do not distort the measurement of the table's vertical geometry.
However, this is not really a disadvantage, as in order to achieve a 'perfect' first layer, we should take care of the accuracy of the measurement,
so that the compensation works accurately, resulting in the print we want.
As some users of 3D printers treat them a little lightly, it is not surprising that there is reluctance to use piezo sensor samplers.
Apart from the disadvantages, piezo samplers have one big advantage.
We are always almost 100 per cent sure of the distance between the nozzle tip and the table, and this translates directly into the quality of the first layer.
The accuracy and repeatability of the measurement is an order of magnitude better than with other types of samplers, whether mechanical or inductive/capacitive.
In addition, piezo samplers do not wear out and do not lose precision even after ten years of operation, and even if the piezo element itself were to break down,
its replacement is a matter of five minutes and costs two zloty.

In order not to bore readers with listing the advantages and disadvantages of each type of sampler, I have included below short videos showing my piezo sampler in action.
I am using a very average CoreXY type printer under Klipper and Octoprint.
Despite the 'lousiness' of the equipment, thanks to the piezo sampler, I get surprisingly good measurements of the table geometry and, consequently, better first layers of my "works".
As I mentioned, the available piezo samplers require quite a bit of dexterity for installation, which is in contrast to my solution,
which only requires the tightening of a single screw securing the piezo sensor.
There are no other requirements for mechanical installation, so anyone who can handle a screwdriver can undertake such an installation.
The issue of configuration under Klipper is also trivial and comes down to making a few entries in the printer.cfg file.
The sampler has a single potentiometer for adjusting the sensitivity depending on the 'noisiness' of our printer.

And here are some short videos showing how the sampler works:
1. Initialisation.


2. G28.


3. Repeatability test.
Repeatability test

4. What you see on the terminal during the test.


5. G29.


6. What can be seen at the terminal during G29.


And that's all the elements of the presentation.
I dare not write a summary, as everyone can draw their own conclusions from the above material.

If any esteemed colleagues would be interested in learning more about the Sampler, I invite you to contact me on PW.
I am posting this topic with the knowledge and permission of Gulson, for which I am very grateful.