How can i get a large print to stick???

[LuckyImperial]

I'll give you a thorough answer. I'm bored at work.

ABS lifting/adhesion issues are quite common and can be solved with a few simple tricks, some of which were glossed over already. The following list, in priority of importance, will help you eliminate ABS lifting.

1. A properly leveled bed with a .1mm Zmin gap.
- When your printer is at it's lowest point you should have a .1mm gap between the nozzle and the bed. People commonly use a piece of paper to test for a .1mm gap. If you can easily slide a piece of paper between the nozzle and the bed then it's too high. The piece of paper should slide under with a little resistance. You can also buy a feeler gauge which offers a little more accuracy than a piece of paper. http://www.amazon.com/uxcell-Metric-.../dp/B0052IRYVS.

- The .1mm gap should be consistent across the entire bed. Move the nozzle to the four corners of the bed using G1 commands (G1 Zxxx Xxxx Yxx F500) and make sure that there is a consistent .1mm gap. If it's not consistent then you need to level the bed with shims. Many people mount there bed to springs and screws to allow for easy leveling. http://www.ultibots.com/springy-corner-bracket-kit-x4/

2. Your heated bed should be set to 105-110C and all fans should be turned off. Any less and the abs will cool too much and contract.

3. Use a proper adhesion film. Hairspray and purple glue stick should work, but better things have been invented. BuildTak or a GekoTek build plate are the two I can confidently recommend. BuildTak is what I use daily, and this stuff is nuts. http://www.amazon.com/BuildTak-Print...ords=build+tak. You may have trouble removing prints after the conversion to BuildTak. If you insist on using Hairspray/blue tape/kapton tape/purple glue stick (the cheap stuff), then less is more. A thicker coat of hairspray is worse than a nice thin coat.

4. An enclosure to keep the heat in. Like Sabastian says, ABS really should be printed with an enclosure. It's not mandatory, but you'll fight lifting/splitting until you do all of the things I recommended above without an enclosure. Another recommendation here is the use of a shell. You can tell your slicer to build a "shell" around your part as it prints which helps reduce cooling and acts as a mini enclosure.

5. The use of a brim. A brim alloys a bigger footprint on the part which will but cut off when you're done.

6. Print your first layer with a thicker extrusion width. It's common to print your first layer at 150-200% extrusion width to give the part more surface interface with the bed.

Mods - you should start sticking threads to eliminate having to repeat this stuff.