Hello,
I have had my TAZ 5 for a few months now. I have been recently having trouble with smaller more complex prints with pieces that snap together or are supposed to have a very tight tolerance. One of the items I was wanting to make was this from thingiverse: http://www.thingiverse.com/thing:586169 which is a combo lock box. Many many people have made this based on the “makes” section and I seem to be having trouble. The parts on this and many other small tight tolerance pieces come out very poorly fitting and require very very extensive sanding to get it to fit. The parts that I have made look to my eye as good quality without any obvious defects or poor printing characteristics.
I have printed a calibration cube from thingiverse (http://www.thingiverse.com/thing:271736) that is supposed to be exactly 20mmx20mmx20mm and it is slightly off. Measuring from the bottom to the top or any of the sides is approximately 20.15 +/- .03. The top appears to have a slightly proud lip around the edge that throws off measurements to something like 20.35 +/- .05.
I have only printed in Hatchbox PLA (this was done with yellow) at 205/60 for my temps. I should note I have made many large cosplay props and other items that just were flat glue together surfaces that came out great.
Is there any kind of calibration I can do to try to get more precise dimensional accuracy out of my printer so that I can print these more complex fitting parts? If any other information is needed please let me know.
Thanks,
Justin
Try lowering the flow % to 95-97%.
Did you use the Calibration piece you printed out to adjust the steps on all three axis to see if it helped?
I will try lowering the flow and reprint and see what that does and repost with results.
I do not know how to adjust the steps on the three axis’. Is there a link to a guide somewhere for this process?
Thanks!
Not that I know of, but it is a simple formula:
Expected Size / Measured size * Current Steps = New Steps.
example for a 20 MM cube:
100 MM / 100.15 MM * 1600.0 = 1597.6
100 MM / 100.15 MM * 100.5 = 100.34
Then you change them in the Configuration-Advanced Settings(latest Taz 5 version) Menu for the Taz(Xsteps / MM, Ysteps / MM and Zsteps / MM.). For the Mini you would have to execute the same function by querying the settings saved in the firmware, and then using the gcode commands as shown in the output of the Gcode Print settings query (M503) for their current values.
I would find and use the 100 MM calibration model somewhere on the site myself, and not the 20 MM calibration cube model. I think it would give better results. No I do not remember where I found the file. 
So I reduced my nozzle flow % from 100% to 96 percent and my cube is now less than .1 over on every side. Is it worth adjusting steps for that small difference?
Yes. You should check the e-steps at some point… the flow % will compensate for fillers and variance in filament. For that reason, try to stick with a filament brand and just adjust flow % to tweak colors… I’ve had good luck with eSUN ABS.
Here’s a guide to calibrating e-steps. People have reported that a slower extrusion rate helps with final e-steps. I’d just use the 100mm/s and use the flow % to tweak… basically get it close o lock into firmware and tweak in software.
If you’re at 96, try 97%. Also sample the filament diameter of the current spool and adjust in slicer as necessary.
It sounds as though you may be overextruding (a picture would help). I would start with calibrating your e-steps (how many steps the extruder motor takes to feed 1mm of filament. I would work on this before you consider messing with the X, Y, or Z steps.
Your issue sounds exactly like the problem I was having on a Mini. Following the link kcchen_00 posted still had me over-extruding. When I slowed the extrusion speed in that calibration procedure from the 100mm/min specified down to 40mm/min (which is much closer to an actual printing speed), I got much better results.
I also found that my Z-offset was just a tad low (the nozzle was starting out too close to the print bed). This resulted in the bottom of my prints coming out a bit wider than intended (since the print was “squished” down onto the bed too far, the filament spread out more).
The combination of bumping the z-offset up by 0.1mm and getting my e-steps set right helped my oversized printing a lot (and especially the “fins” that were making the bottom and top come out oversized even more than the body of the print.