Tried again and decided it was a good idea to pause the print to answer a phone call. The ender did not agree so we’ve got failed print number 2
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Looks better than the first one tho. I think it might have finished OK had it not been interrupted.
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Yup after a couple more basic mistakes, another attempt got 90% of the way there before losing bed adhesion because it’s a bit too tall and narrow. I think I’m gonna use that sort of failed print though because it functions fine and the tip won’t be visible
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A brim would probably solve that issue, and they’re generally not that much hassle to remove.
I usually leave brims on by default, since they don’t take up that much extra time or material, but save iffy prints pretty reliably. Helps with warping as well.
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I’m trying to make an annoyingly big riser as a stop gap until some bigger wheels get here and was wondering about these tactics for wasting less material. I intend to use 96A TPU but if I’ve misunderstood I could use PETG instead
- Go for this version with material removed that’s further from the screw holes
- Print with all the material there in the model, but a lower infill
- oh this just occurred to me as I was uploading the pics, what about trying to mess with topology optimisation in Fusion or something? I might actually try that just for fun
Why chamfer the bolt holes? Won’t they be up against the deck anyway?
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yeah there’s no huge reason, I think it was partly to guide the screw in if I was a little out of alignment and partly because I was just chamfering everything (the big cutout came after and I didn’t go back and add it to that)
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Higher wall count will help reinforce the bolt holes. Don’t skimp on infill when it’s a crucial failure point. I’d print that at no less than 85% infill and would do 95% if it were me.
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Sounds good thanks, any thoughts on the material removed from the middle of the model? I know the bolts are the source of a lot of the compression but the load is spread through two big plates on either side so I can’t tell if it’s efficient or just asking for trouble
I would fillet or chamfer the edges around the square posts for some reinforcement but I used a very similar riser on my circuit board build for a long time on petg and routed cables through the gap which was nice.
Thanks, I did the same on an earlier angled channel PETG riser but having dug out the gcode for that it looks like I went very light on the infill so oops. That part is getting removed tonight and I’ll make a call on whether I’m bothered to mess with topology optimisation or just go with the chunky version
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Right I got 20% of the way through the print before I realised a simple square-ish part with a high density gyroid infill means the print head runs in extended grid-like lines oscillating quickly side to side. ie, vibrates to hell. Didn’t feel like subjecting my poor bastard housemates to 9 hours overnight of that run through an undamped, non-silent stepper machine so it’s cancelled until tomorrow when I can start it again with a different infill
In case you didn’t know, you can add modifiers in prusaslicer to change what kind of infill you want at different parts. For example:
I made the front part 80% rectilinear infill while the block in the back only got 20% gyroid
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Oh that is very helpful, I was wondering if you’d have to run it through a g code fiddler to do something like that
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Select the part and select “add modifier” (I usually go for box) make it the size you need and place wherever. Then modify the settings for that box and whatever part it’s on will have those settings.
Say your riser, 4 boxes in the corners with 100% while the rest is at 20% (crude example)
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I’m partial to prusaslicer’s cubic infill for most things. It’s nearly as isotropic as gyroid, while still being made up of straight lines to avoid shaking your machine to bits.
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Also something I learned, if you truly want solid prints you actually get more dimensionally accurate results and better fill by setting 9999 top or bottom layers than doing 100% infill.
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so in this case I don’t think I even need something hugely isotropic, the load is going to be largely perpendicular to the print orientation. I’m having a look at prusa’s adaptive cubic and support cubic at the moment because they seem to use quite a lot less filament than the others and support in particular generates some weird hollow spots
(I had been using gyroid as default for the isotropy though so I’m definitely gonna consider cubic in future)
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A 3d printing gremlin must have snuck in to my home last night. I swear I locked the door.
I woke up, went to check on all the printers, and they were all done from overnight prints. Printer #3 had printed a spongey, underextruded mess which was odd but the rest all printed normally. It had worn through the capricorn tubing inside the hotend and started to make a pool party inside the hotend 
cleaned all the goop out, cut new tubing, and we’re back in business.
Printer #4 made a lovely E for my name puzzles so I went to start another letter and noticed the extruder motor was stuttering and skipping at points. Tore it down and found that 2 of the 4 wires on the extruder stepper weren’t showing continuity end to end. Soldered them all back together and went to print again.
This time, it was overextruding like it was on the roids. It would only print normally at 50% flow so I peeked at those esteps and it was at 834 esteps/mm 
Set those back to 417 where it was (notice it doubled itself exactly… Hmmm) and started the print again again. It is now fine but what in the actual fuck. Finally leave the room with all printers printing again. Sheesh what a morning.
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I’m gonna start my first tall(ish?) print in a couple of hours, looking around for any tips or pitfalls for PLA
The model is a bit lanky, there’s no extreme angles but the tower is a bit narrow and dainty looking to me. At least there’s a big wide base. Anything I should keep my eye out for?
Edit: Also I need to move my printer away from my desk where I “work” because I keep getting distracted and staring at the bastard