by RetireeJay » 2015-Jan-Wed-08-Jan
That print actually looks pretty good.
The diameter of holes is a well-known problem. Even the big commercial printers don't produce absolutely accurate holes.
But that said, the first things to look at are:
1) Extruder calibration (The steps per mm of filament going in to the extruder. Don't use a stock value, because machines differ; measure it yourself and get it right.)
2) ACCURATE measurement of your actual filament diameter (cut off two or three pieces about 20mm long, and measure with digital calipers for both the smallest "diameter" and the largest "diameter" on each piece; then take the average)
3) Tweaking the "Extrusion Multiplier" to get the most accurate dimensions possible.
Changing the extrusion temperature will have a very slight effect compared to the above three - which are first-order effects.
Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3, upgraded to MK3S