Sapphire Pro - Optical Z Endstop Conversion by petrzmax

Last crawled date: 3 years, 3 months ago

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I had some problems with homing Z Axis. After a few prints my perfectly leveled bed was homing in different position and ideal first layer was wasted. It was difficult to have exactly the same first layer every time. My glass for printing was almost ideally flat, so I don't need to use Bltouch or some similar probe. Also while using Z offset and positive Z offset value Z axis has not much space - Z endstop will be squished etc.
The way to go is using optical endstop. I have used this one:
https://bit.ly/3aiVJ4E
I have drilled 3 mm hole in original endstop holder and screwed endstop using 3 mm screw and 3D printed washer (You can use standard washer). Cables that came with endstop will fit in original endstop socket, but You will need to switch wires in the socket - probably signal wire with Vcc wire. I'm not sure at the moment, I will write it here when I will be looking in to the printer again. Just keep it in mind. It will not break Your endstop or printer, it will just be not working and the green light will be glowing all the time. While it's connected properly it lights up only when endstop is triggered.
I have also designed part which will trigger new Endstop. Print it with PETG if You want to be able to put it on without taking Z rods out.
Also You will need to invert Z endstop logic in marlin.
Change:
#define Z_MIN_ENDSTOP_INVERTING
From true to false
You need to have also disabled Z min software endstop in order to use huge positive Z offset. Just comment out this line in config:
#define MIN_SOFTWARE_ENDSTOP_Z
Using optical Endstop will allow You to use large, positive Z offset.
This means that while homing Your nozzle will be at safe distance from the bed.
Sometimes some plastic may be sticked to Your nozzle which means collision with the bed and probably distracted homing.
Example Gcode for Z offset.
M206 Z1.2
This code will make Your bed go closer to the nozzle by 1.2 mm than Z endstop 0 point.
After this modification I'm always having exactly the same first layer.
I had a lot 3D printers with standard Z endstops, BLtouche's, inductive Z endstops and none of these gave me so perfect homing. I do really recommend it - You will be stunned with the results!
You can find my Marlin setup here:
https://github.com/petrzmax/Marlin