Z Offset to fit 4mm Glass Bed

Hello,

I have problems printing and i figure that it is due to the bed not being level. Not just a normal level the corners problem, but the bed itself bends. I can get around it by adding clamps to the side and printing within 5cm of the clamps, but that is quite useless as I need to reliably print in the centre also.

One idea I have is to use a glass bed which would not bend as much. The bed is 4mm thick, and to make it fit I would need to increase the Z home offset by a few mm  (I can't just tighten the screws enough to take the bed low enough as they don't have enough screw). 

I thought this would be a simple case of  AUTOHOME -> MOVE AXIS -> MOVE Z -4mm -> SET HOME OFFSETS. After this sequence I thought that "auto home" would take me to this newly defined home.

But it does not work. Everytime I start a print the extruder moves all the way to the old home position (directly in the bottom corner) which, if I put the glass bed on, would cause problems.

Does anyone know either:

- how to stop the printer from going all the way to this old home?
- how to make it think that the newly defined home is where to go in autohome?
- another way to keep the bed flat???

Thanks for any advice!


Comments

  • Euzziel EclarinalEuzziel Eclarinal Posts: 15Member
    You're using the stock print bed? Itll bend no matter what. 
    I used glass bed before. It was great, its just that its an added weight to move and my goal is to print fast. 
    So i scratched the glass bed, went to just blue tape and that aluminum heat bed. Much better result. Just be careful no to tear the bluetape when extracting the print. 
    Thanked by 1JamesMcc_Design
  • Samuel PinchesSamuel Pinches Posts: 2,691Administrator
    edited May 28
    @JamesMcc_Design - you can just loosen the screws on the z-endstop switch (above the z motor) and raise it up slightly and retighten there. That will force the nozzle to home to a higher point.
    Thanked by 1JamesMcc_Design
    Post edited by Samuel Pinches on
  • JamesMcc_DesignJamesMcc_Design Posts: 6Member
    Thanks for both replies!

    I might consider getting tape and going directly on the bed.. the glass bed works but takes a lot of effort to get a good first layer - A lot of glue and usually a few attempts. Also yes I think the printer may be struggling a little with the weight, it is making more noise and sounds a bit clunky.

    I did raise the stop switch in the end, maybe I misunderstood the z offset, but I thought it would be possible to set that directly on the printer - but it does make sense that it must go all the way down before setting the offset.

    Cheers!
  • FunInAlaskaFunInAlaska Posts: 18Member
    I recently upgraded to a glass bed. I just moved the Z stop up about 5mm. This was to print directly on the glass. My glass is 4mm thick but I wanted to add a little more adjustment room since my bed leveling screws were VERY close to the frame so an additional mm of adjustment to have those screws a little further from the metal frame
  • y2kats65y2kats65 Posts: 9Member
    i also played around with glass bed.  I like it.  It is relative easy to remove the finish print off the bed.  However, I found even with the adjustment of the Z stop switch, the bed does not glide smoothly on the Y axis.  Worry that this may be straining the stepping motor,  I am now back onto the original bed and the bed glides smoothly.
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