Low PINDA, -2 Z offset
Hi,
I ran the calibration wizard while my z offset was approximately -1.5 and I was unhappy with consistency and the piece of paper got caught, so I lowered my PINDA one thread. Now my Z home is visibly above the build plate and the offset to make it adhere is close to -2. When I run the wizard, it gets very close to the heatbed (not the build plate, the lower one) and with a thick piece of paper it still catches.
What could be causing my nozzle to be too low during calibration but too high during prints, while I have a PINDA set low.
Best Answer by Diem:
The XYZ calibration without the print sheet but with the sheet of paper is a check that your frame is 'square' and the Y carriage is correctly aligned.
The first layer 'Z' calibration with the print sheet and without the paper calculates the starting Z height for each part of the build sheet - this is the one that should be roughly -1.00, it must never go positive and shouldn't be lower than -2.00, each print sheet will have a different value which can be stored in the LCD menu for easy switching.
If you are worried that you have misplaced it so far that you risk digging in then you can pre-check manually:
With the build sheet in place press and hold the selector until the Z adjust setting appears; now slowly lower - or raise the extruder, watching the nozzle and the light on the PINDA - the point at which the light switches should be where the nozzle is about 1mm from the print sheet, if not, adjust the PINDA, now run the first layer 'Z' calibration procedure with confidence.
Cheerio,
You probably moved the PINDA the wrong way - there are a lot of negatives to compound.
Cheerio,
RE: Low PINDA, -2 Z offset
If you're getting close to -2, you have to move the PINDA UP, not down. This way the nozzle can move closer to the sheet before the PINDA triggers, and less Live Z adjustment is needed. Here's a little gadget I created to help adjust the offset between nozzle and PINDA as the zip tie method is suboptimal: https://www.printables.com/model/57192
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Low PINDA, -2 Z offset
I agree that I moved it the wrong way to lower the magnitude of the z offset, but it was the right way to prevent the nozzle from scraping the plate, which is what the instructions tell me to do when the nozzle starts dragging the paper. I'm worried about switching directions and running the calibration, and having it crash into the bottom plate.
RE: Low PINDA, -2 Z offset
The XYZ calibration without the print sheet but with the sheet of paper is a check that your frame is 'square' and the Y carriage is correctly aligned.
The first layer 'Z' calibration with the print sheet and without the paper calculates the starting Z height for each part of the build sheet - this is the one that should be roughly -1.00, it must never go positive and shouldn't be lower than -2.00, each print sheet will have a different value which can be stored in the LCD menu for easy switching.
If you are worried that you have misplaced it so far that you risk digging in then you can pre-check manually:
With the build sheet in place press and hold the selector until the Z adjust setting appears; now slowly lower - or raise the extruder, watching the nozzle and the light on the PINDA - the point at which the light switches should be where the nozzle is about 1mm from the print sheet, if not, adjust the PINDA, now run the first layer 'Z' calibration procedure with confidence.
Cheerio,