this post was submitted on 18 Nov 2024
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My buddy has a cold plunge and this filter started cracking. After looking at it you can tell it's definitely 3d printed (and well)

On the left you can see my first attempt. I just cut rectangular holes in CAD and it's pretty close but not pretty. Printed in PETG on a K1 Max

Is there a way to do this in the slicer instead? I played around with 0 walls and different infill types but that didn't work out

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[–] [email protected] 14 points 6 days ago (1 children)

What if you printed it flat as a rectangle and then rolled it up and sealed the edges? Seems like it'd print better that way, no retractions, no bridging, no fragile areas of like ten 1mm-width layers stacked on top each other.

[–] [email protected] 3 points 6 days ago

That's smart! Gonna give that a try

[–] [email protected] 6 points 6 days ago (1 children)

Ditching the PETG would probably go a long way. Try it in ABS or even PLA and you'll have better shape definition and a whole lot less stringing.

Rather than reproducing the pattern in the original wholesale, you could also consider stealing the idea from e.g. this, which has a "mesh" outer wall that's a continuous loop and thus doesn't require a zillion retractions every time there's a gap.

[–] [email protected] 3 points 6 days ago

Exactly, print it in PLA and see if it's a print or a design problem.

[–] [email protected] 1 points 6 days ago

Print with larger holes, but then use multiple layers. Like Russian nesting dolls, but each "doll" would be rotated very slightly.
Also, try slots in opposite directions. Horizontal slots nested inside vertical slots would effectively create a mesh.
Flat panel inserts could be printed easily and then slid into a circular holder.

[–] [email protected] 21 points 1 week ago (3 children)

That's a lot of retractions. What is this filtering? Maybe you could print a more open structure and line it in mesh?

Also, where is this part in relation to chlorine? I can't imagine a printed part would hold up very well in high chlorine concentrations, but PETG is fairly inert...

[–] [email protected] 10 points 1 week ago* (last edited 1 week ago)

I might be tempted to try turning on 'fuzzy skin' printing above a layer height, for Prusaslicer, if you have a fairly large gap and wide skin thickness it can create an almost-open-weave to it. I used that for some grow baskets for aeroponic racks as well as a lamp shade. The trick there is to print in spiral mode as well.

but I think given the bottom profile, it would have to be done in separate parts- a cylinder for the actual filter, and a cap on either end. ( you can also turn on a skirt for adhesion, which is also useful as a flange for securing it into a cap. basically, there's a recess that it fits in, then a threaded ring screws into that recess.)

edit: here's a screen grab of a quick mock up in prusa.... using a calibration cube (20x20x50mm) using a layer height change to turn off perimeters, infill and turn on fuzzy skin with a point-distance of .6 and a tickness of 1mm. (default .4mm nozzle. yes, that makes a difference on the skin.) It creates a realtively 'open' structure where the layers intersect somewhat randomly while jogging back and forth (think of it as being like a wicker basket,)

it's important to remember when replicating things that they don't have to be necessarily exactly what your replacing. really it just needs to fit in the same space and do the same job.

[–] [email protected] 4 points 1 week ago

I like this suggestion. 3d printing can help with the form factor but creating a mesh filter is a solved problem - why struggle to reproduce that part of it?

[–] [email protected] 0 points 1 week ago (1 children)

Petg should be good for at least a year otherwise asa or pvc should work but they can be difficult to print. According to dr gpt

[–] [email protected] 4 points 6 days ago (1 children)

I hope you meant PLA. Printing in PVC is a hilariously bad idea unless you do it inside a lab grade fume extractor or something. There's a reason barely anyone makes PVC filament.

PVC releases chlorine when heated which is not only incredibly harmful for you, but will also oxidize with and corrode all the metal parts in your printer and probably eventually embrittle its plastic parts as well. This is also why you should not make bongs out of PVC.

[–] [email protected] 1 points 6 days ago* (last edited 6 days ago)

I suspect they meant ABS given ASA is also in their reply. No idea how good either material would be in this application, I just don't think it's possible to print PVC.

[–] [email protected] 19 points 1 week ago* (last edited 1 week ago) (2 children)

~~Tangent: That sounds like a bad idea for food safety. And I'm referring to both the original and the recreation. If it were for myself, I would buy something made of metal.~~ edit: Thought it was a coffee thing, disregard.

On topic: Could you clean up the holes with a hot needle and some patience? PETG tends to be very stringy, which is probably the reason the holes are not well defined. Maybe try tuning your printer to minimise stringing?

[–] [email protected] 9 points 1 week ago* (last edited 1 week ago) (1 children)

it’s not like they’re drinking the water lmao

[–] [email protected] 1 points 2 days ago

It's nice and cold tho, perfect drinking temp lol

[–] [email protected] 10 points 1 week ago (1 children)

Try a smaller nozzle and dry that filament till it grows a mouth and asks you for a glass of water.

[–] [email protected] 1 points 2 days ago

Gave it 12 hours at 80°, and stored in dry box

[–] [email protected] 4 points 1 week ago

U van probably get some improvements by dialing in the printer settings. Otherwise just change the geometry would probably be more effective for less effort. I would reccomment circular holes with the same area as the existing filter would help reduce the issues ur seeing with overhangs. And maybe turn the cooling fan up a touch to help reduce stringing but it probs wont be too effective considering the material.

[–] [email protected] 3 points 1 week ago

i would try printing the filter part as a flat surface (without retractions) directly on the printer bed (only 3 layers maybe) and bend it later to become a tube ( like a "C") i am not sure about petg, i did this bending with pla. hot water comes in handy and maybe a glas bottle. also prepare something to tighten where the ends of the C connect, a border without the small filter holes but some larger holes for something like cable ties or even a printed part for connecting the C edges.