Autoleveling on 3D printers: 9 myths and 12 sensors tested!
Why 3D Printing Stack Exchange recommends it
3D Printing Stack Exchange answerers point people to it when asking which bed probe or endstop is most accurate, since it gives measured precision for many sensor types and notes how bed material and temperature affect them.
Recommended by 2 people across 2 different months, 2018 to 2020.
What it is
Thomas Sanladerer tests 12 bed-leveling sensors, including inductive, capacitive, IR, analog, microswitch and BLTouch types, on a custom-built precision apparatus. He also works through 9 common myths about autoleveling and compares the precision of each sensor with measured data.
What people said
Strong rec FarO · 2019-10 · 3D Printing Stack Exchange · on “Which endstops are most precise?”
Thomas Sanladerer [LINK] performed exactly the comparison you ask [this video] . Check the whole video. The result is that inductive sensors are the most accurate, but they are highly dependent on the bed material chosen. Mechanical switches (bare, no metallic arm) are about as accurate and keep the same accuracy with every bed material (however you need a mechanism to retract them, which may or may not decrease the accuracy). Other sensors are less accurate. In any case, most of them are already far better than required, since anything below 50 microns is fine and basically all of them reach that accuracy. Choose based on other factors such as weight, installation, price. Inductive, after a cali
Recommends 0scar · 2018-03 · 3D Printing Stack Exchange · on “Which proximity sensor to use?”
Tomas Sanladerer has produced a nice video on this topic: [this video] @ 7:31 you see an overview of the precision of various sensors, including the ones you mention. It appears that the M12-4 and M18-8 sensors are more accurate than the M8-8.
Cites BetterSense · 2020-04 · 3D Printing Stack Exchange · on “Are stepper flex couplings important? How important?”
TL;DR: On my particular printer design, it definitely appears the company switched from flex couplings to solid couplings on purpose to improve the printer, and to prevent well-meaning users from adjusting the previous flex couplings. Whether or not this is a good design overall, is left for the reader to decide. It's certainly simple and cheap to use the motor itself as one of the leadscrew thrust bearings, but in the future I might add a micro-adjustable bearing block in place of the motor, and then couple the motor to the leadscrew with a flex coupling. That would be more typical of the way it's done on CNC machines, where the stepper bearings are isolated from any machine loads. Original
Cites FarO · 2020-05 · 3D Printing Stack Exchange · on “What are pros and cons of piezo Vs strain gauges bed leveling sensors?”
I'm designing a dual hotend carriage for a HEVO printer that will run in an enclosed heated chamber and I'm evaluating which bed leveling sensor I should use. I read [LINK] that BLTouch and similar sensors stop working in a hot environment, and likewise, capacitive and inductive sensors are affected significantly [this video] . Piezo and strain gauges (force-sensitive resistors) are my choices. What are the differences in practice? Both related to the heated chamber (70+ °C) and in general at room temperature.