I have to practically cut my prints off my glass bed, i dont use hairspray just a light wash of watered down abs glue.

To me that reads like "I don't use small kitchen knifes, just a light saber or machete"

Abs glue is more heavy-guns than hairspray. Hairspray is much easier apply lightly and sticks less than ABS glue [for me.]

I'm probably just lucky or found the magic combination of hairspray and print footprint/height.

Indeed. . ABS (hairspray on glass) I always had to let cool. PLA I could bash off, but after recalibrating everything (E3D install.. ), it sticks like hell. Go figure. Richrap was probably right when he said, some time ago, that understanding adhesion properties is top of his list.

Elmoret,  I'm looking at quite a big print bed, but printing the same object multiple times at once using say 4 or six hotends all on the same head but spaced sufficiently apart so i'm a little worried that even a little bit out of level might become an issue when your hotends are say 4 inch apart and from one end to the other hotend maybe 300mm.

Hmm thats a lot of prints without levelling. I am looking to lift the glass off between prints as it takes to long for the whole thing to cool down and when printing in abs i am sometimes putting my bed under undue pressure to remove the print. (Out of impatience usually)

I never let it cool, in fact I usually let the extruder head bash it off as it starts the next print. I'm probably just lucky or found the magic combination of hairspray and print footprint/height. Its Filastruder hoppers, for what its worth.

Anyway, I've printed 180mm parts before on the bed with no warp, ABS. I use a full enclosure and a 4 foot blanket around the SD. It just works, so I don't mess with it.

I can't remember the last time I leveled the bed. It was easily 500 prints/6 months ago.

+1 (with glass bed, and provided screws are properly tensioned - which on SD they are, not rocket science anyway

Hmm thats a lot of prints without levelling. I am looking to lift the glass off between prints as it takes to long for the whole thing to cool down and when printing in abs i am sometimes putting my bed under undue pressure to remove the print. (Out of impatience usually)

http://home.comcast.net/~tomhorsley/har … level.html

(most recent results are at the bottom of that rather long drawn out web page :-).

I can't remember the last time I leveled the bed. It was easily 500 prints/6 months ago.

I was wanting to level the bed using steppers to rotate a threaded bar similar to the existing way just electronic. I've seen the fantastic auto sensing and software fix for the bed on here but its important that the print head is perpendicular to the bed to print components that have right angled edges between print bed and the vertical.

So how do more expensive / cheaper printers do it? Are four screws better then three? Or should two points be sprung fixed and only rotate two points using the steppers?

How do professional models do it or cnc machines?

Just a brainstorming exercise. Cheers