So I recently printed some small clips, designed to hold up the water tube for a cooling mist system, which I installed on the back deck. Basically it’s a tube with some small nozzles on it, which spray out a fine mist of water. The system works well, but because of the low roof height, it can get a LITTLE damp at table height (the system SHOULD be installed about 3m above floor level, around the perimeter of the area being cooled).
Anyway, I printed out a couple of batches of these clips, to test different printer settings, see images below:
I use a nominally 0.5 mm nozzle. Now for the first image, I set the nozzle diameter as 0.4 mm in slic3r. This resulted in an extrusion thickness of 0.53 mm. for a 3 mm profile, this meant that is could do two full perimeters, then a small amount of infill, resulting in a reasonably full cross section.
For the second image, I set the nozzle diameter to 0.5 mm in slic3r, resulting in a perimeter trace thickness of about 0.84 mm. This resulted in only 1 perimeter being laid down, and because the infill % wasn’t high enough and the overlap wasn’t sufficient, I got thin walled clips, no good to anybody.
(for 0.5mm nozzle, extrusion = 0.84mm, so to do two perimeters, you need 2*(2*0.84)=3.36mm. So for a 3mm thick profile, it can only fit in one perimeter.)
Lesson from this? think about the thickness of the profile that you are printing, and how many perimeters you can fit in that thickness. if you play with your thickness and infill settings you might be able to get a nice full cross section, but often it’s easier if you just bear these things in mind while you are designing/slicing your models.
I’m sure there will be Reprapers out there who will say that I should fine tune the extrusion multipliers and thickness settings, or use different slicing software, and all of those points are true (I’ve only dabbled with this fine tuning to date). There, I’m not denying it. I just wanted to share some thoughts on work-arounds and things to think about when designing for 3D printing.