Ok, so what makes the printer more accurate?
Is it the print head or what?
3 things: layer thickness, resolution, and material quality.
if you have a die that is for example 4.55mm tall but a printer only able to layer .1mm at a time, your die will print either 4.5mm or 4.6mm depending how you set up your printer. since most printers are capable of resolving an X or Y measurement to .0125mm its of no concern what width your die is because that will be accurate.
with reprap and makerbot Fused Deposition Modelers the materials squirt out and take a moment to cool. because of this, the material can squirt out of the nozzle and kind of hang over the side of the previous layer, further irritating the problem.
the solution would be to stop slicing horizontally and begin vertical printing but that just creates error in the XY direction instead of Z. contacts start being either really open or too tight.