Polypropylene (PP) is a thermoplastic that has a number of properties that sets it apart from other thermoplastics which see common use with 3D printing, including PLA, ABS and nylon (PA). Much like ABS (and the similar ASA), it is a pretty touchy material to print, especially on FDM printers. Over at the [All3DP] site [Nick Loth] provides a quick start guide for those who are interested in using PP with 3D printing, whether FDM, SLS or others.
A nice aspect of printing with PP is that it requires similar temperatures for the extruder (205 – 275 °C) and print bed (80 – 100 °C) as other common FDM filaments. As long as airflow can be controlled in the (enclosed) printer, issues with warping and cracking as the extruded filament cools should not occur. Unlike ABS and ASA which also require an enclosed, temperature-controlled printing space, PP has an advantage that printing with it does not produce carcinogenic fumes (styrene, acrylonitrile, etc.), but it does have the issue of absolutely not wanting to adhere to anything that is not PP. This is where the article provides some tips, such as the use of PP-based adhesive tape on the print bed, or the use of PP-based print plates.
As far as PP longevity and recyclability goes, it compares favorably with ABS and PA, meaning it’s quite resilient and stable, though susceptible to degradation from UV exposure without stabilizers. Recycling PP is fairly easy, though much like with polymers like PLA, the economics and logistics of recycling remain a challenge.
PET-G wins, in my book. I switched a number of years ago and never looked back.
Definitely agree, with the additional mention of TPU. PETG and TPU cover 99% of all applications for printed parts, plus they stick together so you can make composites if needed. I only use PLA for iterative prototyping and/or truly disposable prints, and any situation that would melt or break PETG usually calls for metal parts anyways.
Modified PLA’s are actually pretty great all-around filaments. When eSun PLA+ came out, it was such a game changer that I literally gave away every other brand of filament I’d accumulated, because it just wasn’t worth the trouble to mess with anything else.
I graduated to a Bambu X1C a couple years back though, and have found it’s way less fussy about filament types compared to my old Ender 5. Still, very hard to beat eSun’s PLA+, especially not at that price.
That said, just got a novel hard TPU/nylon composite that I am very excited to play with. I’m amazed that hard TPU’s haven’t caught on with 3D printing yet.
Who makes the TPU/nylon composite? I’m a big fan of TPU for its toughness, that sounds interesting!
A 120C print bed (Bambu lab engineering plate) has worked for me without special adhesives.
I have had good luck with the bambu lab engineering plates too, although I did use glue stick.
Normal PP tape works well too as long as the tape sticks to the bed well enough.
About your Z strength (legit) concern, if reducing the layer thickness to 0.1mm with 100 infill is still not enough for you, try printing the part slanted without much redesign, or design the part with this weakness in mind: I’ve number of part with a long/large bolt on Z axis, adding even more resistance than injection molding part.
am i understanding correctly? is “Z strength problem” the same as “interlayer adhesion”?
it doesn’t seem that severe to me. i try to orient my parts so stress isn’t carried through the interlayer bond…but sometimes i have been forced to break that rule, and i have had some anxiety…but i have had really great successes. it’s pretty rare for a part to delaminate on me, and when it happens it’s usually pretty obviously because of the geometry of the part (two thin walls meeting, for example) and not so much due to the nature / grain of the plastic. fwiw i only use PLA.
i do sometimes wish i had a stronger plastic all around (and i have ‘polymax’ filament for those moments), and i don’t much mind whether it’s slightly weaker in one axis than the others.
Here’s the thing though, you guys have brilliant workarounds, and there’s lots of other techniques that can be used (heat sets, etc.) that will help, but in the end no one is addressing the elephant in the room. We wouldn’t need any of that if we just had (thank you) inter layer adhesion as strong as the tensile strength of the material.
Because you focus on the super cheap at home 3D printing method: FDM.
It has actually been resolved, look at SLS: de-lamination is virtually non existent, but well, it’s outside tinkerer budget!
For me surface finish of 3D prints is a more important issue because of the cost/time of post process: I’m still favoring injection molded part for this reason alone: you have so many VDI finish available, and now, with the laser texturing it’s limitless!
but that’s what i’m saying, you don’t need it to be ‘as strong as the tensile strength’, you need it to be ‘strong enough for my task’. and in practice, i find that the difference between Z strength and XY strength is smaller than the margin of error in my engineering. like mostly i can just make something stronger by making it thicker.
i’m a big fan of 1mm walls for prototyping, but sometimes after some time in the field i find that the 1mm walls are not really strong enough. sometimes they last a long time, as if they’re “almost strong enough”. but then, when they fail, do they fail along the layer or not? anecdotally, in my experience, it seems to be random — they just fail because they’re too thin. so a couple years later i make the second prototype, this time i use 2mm walls.
if i was making the features exactly as strong without any margin of extra strength, then i suppose my vertical members would have to be 20% thicker than the horizontal members, right? but i think the cheapest PLA FDM printer would be the wrong tool for that kind of precision. i think most of my successful designs are 2x or 10x as strong as they need to be, and the slight difference in strength depending on orientation doesn’t mean anything to me.
no one avoids the elephant in the room. we all the time deal with the mouse in the room, successfully.
Try PETG, it’s Z strength is almost as good as XY. I know some lab tests show that it is inferior to PLA, but that doesn’t match my personal experience with it. PLA prints are stronger and cleaner right off the printer. But out in the elements after a few months, they ALWAYS crack on me, especially along layer lines. PETG on the other hand never seems to.
Petg often has good enough layer adhesion from my experience that when it breaks, it does so not along layer lines. It’s a less rigid material than pla though.
One of the advantages of PP is chemical resistance. Acetone, alcohols, and any other solvent you can buy in a plastic bottle will generally not dissolve or soften polypropylene plastic
ABS remains the best all rounder once one moves past the ‘Ender’ phase. The fumes topic is highly debatable and it may be worth it for proponents of this theory to go take a walk in a ABS parts factory, a common material for manufacturing tough parts for many decades now. Lego is a good case in point.
ASA is better in every way.
I dont think I will ever get past the ‘Ender’ phase. with the stuff I do, which is project boxes, jigs and fixtures for low stress applications. If i need anything more robust its looking at a 7grand printer or farm it out to a service … which that happens only a few times a year at most
No need to spend $7k, a Carbon X1 is only $1600 with mmu and capable of printing CF and glass reinforced filaments.
Mind you, I totally understand the urge to get a big boy $7k printer if you have the cash to splash on it.
Manufacturing plants have always been and always will be beacons of workplace health and safety. Nobody has ever lost their life or become partially or permanently disabled from chronic exposure to chemicals in a factory!
I’m going to go play in a pile of asbestos right now!
I tried to print a Pikachu in Polypropylene, but my printer errored and said I don’t have enough PP to do that…
My biggest grievance against polypropylene is that its a high density plastic that can not be glued, solvent welded or otherwise tampered with
quote wikipedia:
Polypropylene belongs to the group of polyolefins and is partially crystalline and non-polar. Its properties are similar to polyethylene, but it is slightly harder and more heat-resistant. It is a white, mechanically rugged material and has a high chemical resistance.[1]
Polypropylene at room temperature is resistant to fats and almost all organic solvents, apart from strong oxidants. Non-oxidizing acids and bases can be stored in containers made of PP. At elevated temperature, PP can be dissolved in nonpolar solvents such as xylene, tetralin and decalin
Can you get anything like the last sentence to weld this stuff? its used for holding nasty ass chemicals that can rot most substances on earth
I have only used PLA for this purpose but filament friction welding works quite well for welding parts, and should work with PP. How strong of a bond does solvent welding leave? I would imagine it wouldn’t be that strong because of uneven drying as the edges dry and the middle traps the solvent, and an overall thin layer of bonded plastic…
Bye!
Oh noes! What will we do without you??
Clear packing tape? On a heated bed?
That stuff is messy enough without the heat!
I can just imagine the mess this must leave behind.
How about this? A layer of blue painters tape with a layer of clear packing tape over that?
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