Impact of hairspray, etc on glass with IR sensor

  • I'm trying to decide between trying another BLTouch sensor or trying this IR sensor. My issue is that I use a glass on a (matte black coated) aluminum heat spreader, and frequently use hairspray, or glue stick on the glass. The information I've found on this sensor states "Coatings on the glass affect the trigger height slightly."

    How "slightly" is slightly? Greater than 0.01mm? 0.05mm? Considering that I frequently use 0.1mm layers, will I need to pre-determine different Z offsets for "plain glass", "glass with hairspray", and "glass with glue stick?" If so, what level of consistency could I expect if the amount of hairspray on the glass plate differs, or if I use a different brand of hairspray that might reflect light slightly differently?

    Thank you

  • I have been using the IR height sensor for close to two years, I think, and I would guess that hairspray would not be much of a problem but since glue stick is so irregular that could be a problem. Be careful not to get the hairspray on the sensor of course. My winning combo has been the IR sensor with Printbite. I have been using the original Printbite but I have some Printbite+ on the way so we shall see how it stacks up soon.

  • administrators

    It depends on the glass and the hairspray, but you might see differences of around 0.1m with/without hairspray, and even more with glue stick

  • I could not get a good result with glass on black paper and hairspray. Investigating I'd get a very flat mesh (really flat), add the hairspray, retry and the bed mesh suddenly has high and low points all over; with a mean variation of 0.1 to 0.15 mm. Running calibration repeatedly also gave huge variations on each run, bed tilt etc might go between +2 and -1 degrees between subsequent runs. Before that spurious results on individual probes during calibration were throwing some prints out of whack, airprinting the first layer, nozzle crashing, I had it all and it was all very random and frustrating.

    The same test after biting the bullet and painting the glass back black was much better; the hairspray has far less effect, and the mesh stays flatish, without individual high or low points.. For hairspray this was important to work out because I need to disturb the bed to spray the glass on my balcony and then re-calibrate before printing (at least until I can get a better bed mount setup).

    Plus black painted glass looks REALLY COOL in a webcam.

  • administrators

    Glass that is black in the first place would be even better!

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