Prints not adhering to your build plate?

One of the most frustrating issues we come across with our 3D printers is the lack of adhesion of some prints to the build surface.  It doesn't seem to matter whether we use glass, perf board (such as on the Afinia), blue painters tape or Kapton tape or hair spray, there always seems to be a print or two that just doesn't want to stick.

After many (and I do mean a lot) prints here's what we seem to have learned from our experiences:

1.  The build plate must be level (pre-heat the plate)!!!  This is one of the easiest ways to ruin a print.  Especially larger prints that take up a larger portion of the build surface.  Here's a tip; keep an eye on the skirt (on some slicing software you have the option of altering how many loops and layers of skirting there are as well as the distance from your actual print the skirt is placed).  If you're not sure what a "skirt" is, this is a line of filament that is laid down outside of the perimeter of your actual object you are printing.  My assumption is that the skirt purges the extruder a little and allows you to see if the filament is being laid down in a consistent manner. 
Keep a close eye on the skirt as well as the first layer of your print to see if the filament width being laid down is consistent.  If it's wider in some places and thinner in others this can be a good indication that your build plate isn't level or flat.

2.  The build plate cannot have any of your nasty finger prints on it!!!  This is especially true for the Afinia perf board.  We have found that wiping the board with acetone just prior to a print can help a lot. 

3.  We pretty much use hair spray exclusively for adhesion on the Hyrel and the makerbots (Hyrel is a glass plate, makerbots are plastic and aluminum).  Interestingly enough, it seems to matter what brand as well (see the pic below).

Our setup with the hair spray happens this way; we clean the surface thoroughly with acetone, let it dry then spray a healthy dose of hair spray all over the plate.  Let it dry then re-apply one or two more times.  It hasn't seemed to hold as well with just a single layer of spray but after a few sprays and dries we have had good luck.  Doesn't have to be re-applied after every print either as it seems to last for quite a few jobs before it needs to be cleaned and prepped again.

4.  Pre-heat the build surface prior to tramming (leveling) and / or printing!!!  Heat does strange things to build plates.  Expansion and contraction, warping can have an effect on how level your plate is.  Obviously, PLA printing does not require this but since we print mostly with ABS it's a good idea to pre-heat the build surface whenever you are preparing to print or when you are tramming the bed.

These are just a few suggestions for keeping your prints stuck.  Let us know if you have any other suggestions we can try!