Printing on top of another object

[reed2569 0]

Is it possible to start a print above the bed (elevated) to print on top of another object? Example: placing a precisely positioned 127mm high 24mm diameter cylinder on the bed, then starting the print at 127mm high, printing a ring on top of the cylinder.

[IR15HM4N 0]

You could try adding an extension to the z-axis limit switch to “fool” it into thinking the bed is raised up. Add a piece to the guide that hits the limit switch. 

[NickB 2]

Go to the settings and disable 'automatically drop models to the build plate'

then you can change the Z hight of the model. (not sure if this will to the job)

But why would you want to do this. why not glue it to the cilinder?

[gr5 2,172]

If you do that make sure you "play" the beginning of your print job using layer view and the horizontal and vertical sliders to see the first few moves in layer view to make sure nothing will hit your part.  Note that the gantry is probably less than 127mm tall on many printers so you have to realize that your gantry may hit your part as well as the hot end (and fans, etc) because it will have to level the bed before starting your print.