To use a printer you must think like a printer! Or at least know some of the limits. The supposed resolution of my new mini printer is 0.1mm. It doesn’t necessairly mean you can print something that size, just that the stepper motors and gearing are able to potentially displace 0.1mm in X Y and Z. The nozzle diameter is 0.4mm, which would likely mean you can’t make features smaller than 0.4mm, and making anything between 0.8 and 0.4mm might turn out funky because of diameter overlap. Well lets find out.
Pins and Holes
I made a pin a hole test pattern. They started at 0.25″, went down by 0.05 till it hit 0.1″, then went down by hundredths till it got to 0.01″. I then measured the actual results to see what happens. The pins were quite accurate until it got below 0.05 inches. Everything below there just came out at the same diameter. My 0.8mm prediction wasn’t far off, 0.8mm = 0.031in.
The holes had an undersizing problem. It is consistently 0.01″ narrower until it gives up around 0.02. I don’t quite know why this happens, but the fancy professional printer we have at work does the same thing below about 0.1″. I think everything over 0.25″ ought to be ok.
I moved on to raised and lowered text. Being able to label parts with information is quite useful. Engraving or having raised text is essentially all the same as far as the printer is concerned. I suspect the raised text might be faster because of how the walls and support are built and calculated.
Both sets turned out pretty well. The text is very readable and looks decent down to 0.2″ high text. The 0.15″ is readable but the inside features of the recessed text is starting to merge with the side walls, and the raised text is starting to mush together. The 0.1 recess is readable, but looks bad, while the raised text is pretty blobby. Finally, neither did much for the 0.075″ text. All text was done with Arial Black text set on Bold. Different fonts and settings might yield better results, but I doubt they will be much better.
The printer’s ability to print overhanging structures is amazing. You can bridge small gaps without too many issues, but that is something that shouldn’t be used much. Angles on the other hand can be quite common. How far can it go? 45 degrees? Further?
A lot further it turns out. The top surfaces look great, but by the time the printer gets there the surface below is already quite solid. It is the bottom surface you have to look at. The 30 and 45 look great. 60 and 70 are a little zitty and wavy, but quite serviceable with a bit of sanding. Really fine model making might suffer, but when making basic structures, even 70 degree overhangs are not unattainable.