3d Printed Parts Longevity.

I have had plenty of products eventually decay beyond use. Sticky rubber coated binoculars, die cast model cars from my childhood having crumbled away, and even a fishing shoulder bag that rotted most probably due to UV light exposure.

I know nothing about 3d printing, but I see it being used in large format field cameras, light meters and housings for enlarger controls. Also spares for drum printers.

My thoughts have turned to the life of these products. Especially as some items are being sold for a fair old price. Not exactly disposable.

Do they eventually crumble away, or will the environmentalists be complaining in a hundred years time about the scourge of more plastics polluting the planet?


Any ideas?

It depends on the material they're printed from. Popular FDM materials are PLA and PET. PET is the more durable of the two. In both cases, UV is the main thread as it tends to make plastics brittle; PLA and PET are no exceptions. PET is more chemically resistant. PLA is bio-degradable, but this process relies on very specific parameters, so don't worry about PLA parts spontaneously starting to rot; it doesn't happen.

For all 3D printed parts the main risk is mechanical strain. These parts are generally much weaker than molded or extruded parts; FDM parts just don't have the same kind of integrity as molded parts due to how the manufacturing process works. Especially in cold weather I can easily see 3D printed bits snap or scatter. The main determinant of how well a part will last is how it's engineered; a properly engineered 3D printed part can be very sturdy. However, like all materials, there are limitations and in some applications they just won't work well. The example came up recently of a wind lever on a 35mm camera - that's an application where I'd put zero to no trust in a 3D FDM printed part (but quite as little in a molded plastic part, for that matter).

BobUK said:

will the environmentalists be complaining in a hundred years time about the scourge of more plastics polluting the planet?

Click to expand...

3D printed parts contribute to environmental problems associated with plastic pretty much like any other plastic product. However, that in itself does not tell the full story about the functional longevity of these parts.

In the above, I've reflected very, very briefly and superficially on two particular materials; I've not touched upon so-called 'resins' used in resin printers, sintered materials etc. and the failure modes of parts are so diverse and expansive that it's hard to even begin to tell the full story.

Having said that, a properly engineered, 3D printed part can last a long time; whether these parts will turn out to be quite as resilient as other engineering materials used, only time can tell.

I have seen some 3d printed parts made as a composite: they punch metal rods through them to give them additional strength. That could be helpful depending on the application. You could also give them a coating of enamel paint to extend UV longevity, if it's a low abrasion part where the paint won't just rub off.

Then, there's the option of using the 3d print as the cast and forming the part from a different, low-temperature castable material.

Totally depends on the application.

I have had a 3D printer since 2019 and it has been in frequent-to-nearly-constant use the entire time. A huge amount of the designs I make and print (and the designs other people make but I still print) are photography- or darkroom-related. Half my darkroom is made of custom 3D-printed parts, it seems. Dodge and burn tools, the housing for my customer enlarger LED head, the housing for my custom enlarger timer/controller, a 4x5 glass negative carrier for my enlarger, a 4x6 print easel for PCX, various wall mounts for things like my red LED clock, my test strip maker, custom containers for 1-shot chemical storage of pre-measured quantities, etc. etc. etc. I have also messed around with 3D printed cameras (from simple pinholes, to more complicated pinholes, to a fully function monorail technical camera that takes Mamiya roll film backs).

Most of this stuff doesn't get exposed to much (if any) UV light, extreme temperatures, or significant mechanical force. I suspect it will last more or less forever. I have a couple of custom designed arca-rail L brackets that I use on some of my 70s-era 35mm SLRs. If a part is going to get any kind of structural use, I print it from PETG or TPU. There are arguments for using something even stronger like ABS, Nylon, Polycarbonate, etc, but I'm not set up to handle filament types with nasty offgassing, so I stick with PLA, PLA+, PETG, and TPU for everything. Some of these L brackets from PETG have been in use for upwards of two years without any signs of breaking. They are less svelte than current aluminum L brackets in common use on digital cameras, but the extra chunkiness of the design is probably why they haven't started to break or degrade.

I dunno. Much of what appeals to me about the intersection of hobbyist-level 3D printing and film photography/darkroom work is the excitement of being able to innovate, design custom solutions, prototype rapidly, and... easily/cheaply replace things that break. If you're buying your printed objects, you lose many of those advantages. I rarely buy 3D printed items at all, and understand the hesitation of spending significant money on something 3D printed.

Perhaps the most notable exception for me is my Reveni Labs spot meter, which features a 3D printed housing for the lens and electronics. I've been using it a lot over the past couple of years, and have had zero issues with the 3D printed casing. Maybe someday it will degrade. If/when that day comes, I bet I could reach out to Matt at Reveni Labs and purchase a replacement casing for a few dollars. Heck, if I felt like it I could probably design and print my own casing for it.

There are a very wide variety of materials that can be used for 3D printing. PLA and PETG are popular, as mentioned, but so is ABS. Less popular, but still very much available even to hobbyists are polystyrene, nylon, vinyl, polypropylene, thermoplastic elastomers, various carbon fiber impregnated filaments, and many more.

So, I don’t think it’s possible to make any blanket statements about longevity/durability.

Personally, I only print with PLA which has been fine, but I don’t make anything that I expect to use outdoors much or to last super long.

There are two issues - the longevity of the material under specific conditions of use, and the structural design with regard to the material and printing limitations.

For the material, temperature, prolonged moisture contact, and UV are the issues. There is not a lot of literature that I have found on this - maybe in some materials science journals?

FDM printing can introduce structural weaknesses because of the limits of layer adhesion. This is one of the issues with carbon fiber infused filament - it is great for tension, but you cannot always print it in the right orientation to get that benefit. Design is critical as it can go a long way in mitigating other issues.

3D printing scores in that complex shapes can be designed and produced cheaply, and are often good enough. I don’t have a wood or metal shop, so 3D printing works for me in many cases.