PEI build surface
PEI (Polyetherimide), also known as Ultem, is a reusable "maintenance free" build surface for both ABS (with a Heated Bed) and PLA (hot or cold) requiring no additional adhesives such as glue or tape. PEI is appealing due to its "no-surface-prep" conditions, which make it convenient to work with. Additionally, printing on PEI requires no support rafts as parts adhere directly to the surface with no issue.
More Information can be found: http://kuehlingkuehling.de/2013/04/02/development-roundup-metal-hotends-new-print-surface-rjmp-linear-bearings-watercooling/
How do I use this?
Purchase a sheet of 0.03" - 0.04" thick PEI, thinner can be used but it is more difficult to apply exactly flat to your surface. Laminate your sheet of PEI using 3M 468MP[1] Adhesive Transfer Tape to a glass/mirror print bed, keeping in mind that 3M 468MP is a very tacky tape that is prone to clumping. The type of glass you choose does not matter as long as you provide even heating of your glass (for example, if using a Mk2A/B heat bed, have your glass cut to 200 mm x 195 mm). The side of the PEI you choose (if your sides are different) does not matter, as it simply changes the appearance of the part underside.
Once you have laminated your sheet of PEI onto your glass, simply re-level your print bed and set your heated bed to 85 C for ABS and print away. Parts should come free from the surface with almost no issue at all. PLA does not require heat, but turning the heated bed up to 45C helps.
Suppliers
http://www.amazonsupply.com/dp/B00CPRDDLY
http://www.amazon.com/dp/B0013HKZTA/ref=biss_dp_t_asn (0.03" or 0.76mm)
You can also find PEI labeled as Ultem from suppliers such as McMaster-Carr: the 0.040" variety is suitable for printing.
Usage
Laminate 0.030" or 0.040" thick PEI onto glass or mirror tile (to preserve flatness) with 3M 468MP[2] Adhesive Transfer Tape. Beware that 3M 468MP is very sticky and prone to clumping, which will cause unevenness of your print bed.
Additionally, if your PEI has two different sides (one matte and one glossy) it is unknown the difference these sides cause to prints. Tests are currently being performed to determine the difference - so far, I (Odonay) have found that the matte side adheres well and serves its purpose, but others have found that the matte side loses its ability to stick to parts after about 10 prints.
If printing ABS on PEI, a heated bed is still required. It is recommended you start out at a base bed temperature of 80 degrees C, but I (Odonay) was having a problem with parts lifting ever so slightly until I set my bed temperature to 90 degrees C. Note: lifting may be due to lack of regular cleaning and maintenance.
Cleaning & Maintenance
Use isopropyl alcohol, methyl alcohol, soap, Heptane, Hexane, or Naphtha. Avoid ketones (such as MEK) or strong bases (such as sodium hydroxide).
In other words, PEI can be cleaned through the use of Isopropyl Alcohol, which will theoretically help adhesion should you lose it.
Note that as of the writing of this article (02/05/2015), proper tests have not been carried out to determine the best method of cleaning PEI, the recommendations above are sourced from a brochure for Ultem. Please add cleaning methods that have worked for you.
Known to work: Isopropyl Alcohol (70%)
