Joe – Page 18 – Joe's Blog

Infill Patterns

I spent a decent bit of time yesterday tuning my printer for using the black PLA I ordered with it, and since I was printing ~50mm squares to go under the printer feet so it would sit flat on the wire shelf where my old printer was I had good top/bottom surfaces to play with alternate infill patterns:

Clockwise from top left (as labeled in slic3r): octogram spiral, hilbert curve, archimedean chords, concentric
Not shown: rectilinear (the default)

Of those I like the hilbert curve pattern the best, but slic3r isn’t kidding when it labels that with “(slow)” – it took a remarkably long time to do the top and bottom layers of that print. In general I’ll probably stick with rectilinear for most prints, but I may play with the others some more when I’m not printing objects with such large flat surfaces on top/bottom.

I probably should take a better picture of those using natural light, but that’ll be tricky now that I’ve finally gotten the sd card reader to work (card format matters: fat16 works) and put the printer where I intend to keep it:

I will need to figure out a lighting solution for it at some point: that corner has never needed light and keeping a flashlight nearby is somewhat less than ideal for examining prints-in-progress.

Talore was remarkably unbothered by having the printer there, though it looked like she was having trouble sleeping through the vibration of 40% honeycomb infill, which shakes the entire shelf a bit (but not nearly as much as it shakes my project table). I don’t think Dash has really discovered the printer yet. I would think he’d be interested in it when it’s moving, but I don’t know that he’s been high enough up to actually see on top of the build platform while it’s in motion yet (his hammock is a bit lower than that shelf).

Anyway, now that I’ve got the printer pretty well set for that filament I’m printing some small calibration objects to fine tune it and see if I can drop the layer height to .1mm (I have one passable print at .1mm with the blue ABS that I think I now know enough to improve, but my first try with PLA didn’t work at all).

Pile of Experience

I spent most of today trying to figure out how to get large prints in ABS to complete without curling up in the corners and ruining the print. Here’s the stack of LCD faceplate attempts that I produced.

The first attempt used the same settings as the calibration cube, but after about an hour it had curled enough in two corners that it was clear it wasn’t going to complete in a useful state. The second through fourth prints were attempts to print with the printer set to faster speeds to see if it would be able to keep ahead of the curl. Turned out no, and I had to bump the temperature up by a good bit to keep it from randomly jamming because it was trying to push plastic through the nozzle at about the same speed that the plastic was melting. The last prints I started playing with infill settings – it’s not a structural piece so the default of .4 infill is probably way overkill. I also had to slow down the travel time because it skipped steps a couple times.

The successful print was with .1 infill, a 1 mm brim, and the travel speed limited to 200 mm/s (down from a high of 500 mm/s). It still took over half an hour to print and there was slight curling in one corner (I’ll try increasing the brim next time to see if that’s actually what was helping). I think I’m going to need a proper heated chamber to print large pieces of ABS (luckily most of what I want to do in ABS is small pieces), so I might start trying to work with PLA tomorrow even though it’s not recommended for the E3d hotend I have.

The banding I was getting last night turned out to be from one of the threaded rods being bent. The design prevents it from pushing the extruder back and forth so I didn’t expect it to be a problem, but as it turned it was raising/lowering the end of the X-axis from where it should have been. I don’t think I quite have it perfect yet, but it’s much better. I also smoothed out the motion of the Z-axis while I had the rods removed so now I shouldn’t have any binding.

Also, because I recorded it, here’s a video of a short print from start to finish:

Success!

Against all odds my first print was a success (using ABS even):

That’s after everything cooled down a bit, you can faintly see the traces on the bed where the pieces were before they popped loose (due to the bed shrinking as it cooled at a different rate than the plastic) and I moved them. It’s decidedly not a perfect print (horizontal banding, some spots where the perimeter pulled apart between layers, some waviness on one corner where I’m guessing the layer started), but considering the ambient temperature in my living room is 18C I’m surprised I got a successful print on my first try.

Interestingly, the quality of this piece is actually good enough for the first couple things I was planning to print so I may do some printing before I dive into further calibration.

As promised, here are pictures of the build process:

Entire kit laid out on my project table.