Is inductive sensor required?

[DonaldJ]

I'm not a fan of automatic bed leveling. If I got a Metal Simple, could I disconnect and remove the sensor?

[RetireeJay]

I would say yes you could remove the sensor. Of course you won't be able to use the G29 command. But you still need a way to adjust your Z clearance. On a Simple, I guess you can do it by hand if you put a knob on top of the Z threaded rod. The firmware assumes that wherever it is when it turns on is 0, 0, 0. So if you manually adjust every time you turn it on, you should be OK. That's what the first Simples did before they added switches.

There probably won't be a place on your machine pre-designated to install a mechanical Z switch, nor a way to adjust the trip point of said switch. But if you can design a way to install a switch, you'll find it more convenient than manually zeroing. Unfortunately, the Simple Metal is not as friendly for user hacking as the wooden version; but it can be done.

[DonaldJ]

[teicher]

I would recommend that you still go through the Z offset calibration steps for the probe and get it working, then simply remove G29 from your starter gcode.

[orangefurball]

[RetireeJay]

[DonaldJ]

[teicher]

Ah, if you're going to use a glass plate, I agree with the you on not using the probe and favoring a mechanical switch.

[Sagbot]

I run with no auto level and no z limit switch. I removed all Z homing from the Start G-code.

After turning the bot on and heating up the hotend, I turn the screw to position the tip near the surface. I still use a piece of paper and try to get it close.

Then I execute G92 Z0 to zero the Z axis.

*** This is a bit dangerous because if you forget to run G92 Z0 after lowering the head yourself, the head will plunge into the surface.

When the print starts, I adjust the screw by less than 1/8 turn (that's 45 degrees) as it prints the perimeter. 1/8 turn is about 0.1 mm.

The whole process takes 15 seconds, and once the calibration is made, it's good until you turn the bot off. Print after print works. You can always leave the bot on overnight if you don't enjoy the manual calibration routine.

At this point I don't want to install a limit switch for Z, because RetireeJay and others have had significant difficulty setting one up with sufficient precision.

I'm printing PLA on a polycarbonate slab and use a 3 point bed levelling scheme.

-Mike