Vertical Axis Offset

[Thor]

I installed a glass plate on my print bed and now the adjustment screws are just about maxed out. I think I saw a post somewhere that mentioned putting in an offset for the Z axis. I have looked at the menus on the printer and don't see a way to do that. Does anyone know if it is possible, and if so, how to do it?

[Mjolinor]

Not possible I don't think. You need to stick a lump of plastic to the switch.

[EagleSeven]

Yes, I've seen printable adapters at thingiverse.com
that attach to bed-plate and activate switch sooner,
but I have not needed them, since glass added to ours is only 3/32" thick.

[Thor]

I suspect that there is no other option. I did, however, find the reference to changing settings. It was in a post by Horendus on 9/1/15 ( I think I will separately reply to that post and ask how he did it):


Tip #4: In the printer settings, change your Z axis offset to -2mm, loosen your bed screws all the way and re level with this new offset. This adds 2mm less tension on your bed plates spring suspension. Its like a car, hard suspension will allow you to feel ALL the bumps. We don't want that. After I did this I was able to get resonance free large flat prints at up to 45mm/s. Excellent gain.

[EagleSeven]

In Makerbot-2.4 settings there is one : "startZ": 0.2

To change that you must first Create a new Profile and then Edit it.

I'm not sure if that's the same thing or not ??
But looks like that may be same setting.
I've never tried changing that one yet.

[Thor]

That may do an offset for a given print job but I would like to have the offset be set until changed so that I can level the print bed with the offset. I think that I will try printing the offset shim from thingverse and see how that works out.

Thanks

[Captin]

I installed a 4mm piece of glass on my CTC printer I then printed a 4mm adapter from thingiverse and it just slots on the the back of the bed under the switch to activate the switch sooner. Works 100% with no messing with the firmware or printing offsets or even the bed leveling screws.

I did have a problem with various clips to hold the glass down as when printing to the extent of the bed the second nozzle would catch on the clips. So I 3d printed my own design and put one on each corner. They hold the glass firm whilst not protuding above the glass, and also make it easy to remove the glass when letting it cool for better removal of the printed part.

I bought 5 piecies of 4mm glass from a local glazier for £5 the exact size of the bed. I just ground the edges with a diamond bit in a dremil to stop myself getting cut.

I now get much better adhesion with PLA and ABS with slurry.

[EagleSeven]

Great !
Thanks for the Info !

[Thor]

Good information, thanks. As pointed out to me by EagleSeven, I just hold the glass plate to the bed with hairspray but I will print the adapter and see how that works.