Setting the Z offset

This is something that can need to be tweaked even if you've got bed level sensing, especially if you've not used your printer for a while. This article will assume that you're using Marlin firmware.

Where is it?

Control > Motion > Probe Z-Offset
 

So the number is..?

The number that you see is in thenths of a mm I think

The lower the number the lower the nozzle: -1.75 will be closer to the bed than -1.71!

How To:

The way that I readjust is to 

A Quick History

To give an indication here are some notes that I drew up one afternoon for reference, the offset that you need might well be different on your printer/setup but the behaviour of the test prints and the changes in measurement to achieve them should be roughly the same. I was also looking at the bed and nozzle temperature as I was having a really bad day to begin with:

• Bed: 50 Noz:194 Zoff: -1.72
  • Good, not quite, not adhering in all places, needs help
• Bed: 50 Noz:194 Zoff: -1.75
  • Great adhesion, clicking
• Bed: 50 Noz:194 Zoff: -1.73
  • no help, nearly there, filled in first layer, not everything stuck, popped from bed
• Bed: 50 Noz:194 Zoff: -1.74
  • No help, didn't all stick, odd corner issue, freak?
• Bed: 50 Noz:192 Zoff: -1.74
  • popped from bed