General Filament Chat

Not a problem. Thanks for confirming my cynicism about AI! ;) Great tool but can totally bark up the wrong tree.
I work in IT....we don't call it cynicism....we call it "experience"! :D
 
I need some advice on the type of filament to use. I need to print a load of arms to hold a window open at various opening distances and they need to be able to cope with high winds. It needs to cope with the window being pushed/pulled by the wind. I tried PETG and that wasn't strong enough so I got hold of some PETG-GF and the first one of those has just broken as well. Should I be looking at ABS, PA or something along those lines? This is the model in question, in particular the long arm with notches in it, forget about the bracket that the arm locks onto as I am using the original metal ones.
 
I'd suspect it isn't the filament but the design or the particular strain on it in your situation. How are you printing it and where and how is it breaking?
How: If you're printing it standing up the layers will be stacked all the way up that arm and those are the weakest parts between layers.
 
I print it lying down and my latest ones I used 100% infill which made it much stiffer than the previous one which just used the supplied profile but I am more than willing to tweak things. The weak spot is above the notch where it's thinnest and that's where they keep failing. It works brilliant but just isn't strong enough to withstand the winds we get here. I would love to make the bit above the notches taller so it would be stronger but that is beyond my capabilities at the moment as I am still very much a learner at this.
 
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Can you get a pic of where/how it fails, might be a case of the direction its sitting on the bed and the layers arent helping with directional load or whatever its called..
 
pastymuncher said:
I print it lying down and my latest ones I used 100% infill which made it much stiffer than the previous one which just used the supplied profile but I am more than willing to tweak things. The weak spot is above the notch where it's thinnest and that's where they keep failing. It works brilliant but just isn't strong enough to withstand the winds we get here. I would love to make the bit above the notches taller so it would be stronger but that is beyond my capabilities at the moment as I am still very much a learner at this.
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Scale the thickness of both pieces using the slicer. It’s super easy, as long as both pieces are scaled by the same %, they’ll continue to work together.

Edit: ABS is more brittle than PETG so it’s not going to improve the strength IMO, batter with PETG or a proper engineering filament.

IIRC, CF filament is actually weaker than regular, the benefit is in the finish which isn’t the objective here.
 
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Stiffer and maintains dimension better but can be weaker or not significantly stronger. GF according to a test I watched recently is the same but less abrasive and not as strong as CF. Quantity and length of the fibres is very variable (as is price) so it can change quite a lot across brands.

Good call on scaling in the slicer - I'd totally forgotten that option.
 
Thanks for the suggestions. I will have a play with the scaling and increase the wall size at the weekend and report back. Not very often you come on this forum and actually get suggestions not to spend any money these days. :D
 
I increased the width to 140%, increased the walls to 5x, infill at 100% and changed from monotonic to rectilinear infill and it's much stronger now. It's very windy today so I will fit one and see how it fares. Many thanks for the help.
 
100% infill is not what you want really walls give you more strength. Enything over 40-50% infill is waste of time and plastic. Do 5-7 walls
 
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