What to do with failed/unwanted 3D prints?

  • I am planning on getting a 3D printer soon and I was just wondering, what do you do with 3D prints that either failed or were prototypes that you no longer want?

    I tried looking online but the closest I got was effects on environment, turning prints back into filament, or restarting a failed print half-way, none of which were the information I was looking for.

    The solution should be somewhat eco and just keeping unwanted prints in a box somewhere isn't a very good solution either.

    Finishing off failed prints isn't totally applicable because it wouldn't apply to prototype prints that you don't want to keep.

    Is there anywhere to send failed 3D prints for professional recycling, or are there any recommendations for properly disposing 3D prints?

    In case this is of any use, the printer I am planning to get uses filament that can be made of PLA, ABS, Nylon, and possibly other materials. The printer is this one specifically (https://www.kickstarter.com/projects/101hero/101hero-the-world-first-us49-3d-printer) from KickStarter.

    Please note, the 101Hero Kickstarter is widely expected to be either a massive flop or utter garbage. Best case scenario, you get a very low quality printer in something like a year. I strongly recommend you pick a different first printer. See http://3dprinting.stackexchange.com/questions/1211/least-expensive-3d-printer/1212#1212

    Some of us mix ABS failed prints with acetone to make "abs slurry" (helps with bed adhesion and gluing ABS prints together) or grind it into pellet and extrude our own filament. Otherwise, printed plastic is just plastic, throw it in the proper recycle bin for plastics, and if there isn't any in your state, just throw it away, the government and giant corporations pollute orders of magnutides more than you will in your whole lifetime, environmental impact of failed prints in the trash can should be the least of your concerns then.

    101Hero can only print PLA. The extruder can not get hot enough for ABS, neither is there a heated bed.

    I found this website by searching on Google, 3D Printer Filament Recycler l RePLAy 3D. It looks like a recycling club were you get points / can exchange it to buy filament or something like that.

  • The "obvious" answer is re-grinding the prints and making more filament. Unfortunately, this isn't yet a very economical or simple operation. A decent filament extruder capable of holding acceptable diameter tolerances is around $1000, and even then they can be pretty fidgety to operate. You have to have a LOT of volume throughput in your filament extruder for regrinding to be an economical proposition.

    Some of the reasons why recycling prints into filament can be difficult:

    • Most plastics will degrade to some extent each time they are extruded. (Both by the 3d printer and by the filament extruder.) PLA will thermally degrade with extended exposure to heat. PET will hydrolyze and break down if not meticulously dried to remove moisture prior to heating to the melting temp. (PETG seems to be less prone to hydrolysis damage than plastic bottle PET, but it still happens to a limited degree.) ABS holds up to extrusion conditions better than most, which is part of why it's favored for injection molding, but there's still the potential to affect properties by depleting additives or cooking out plasticizers. In practice, this means regrinds generally need to be mixed with fresh pellets at some ratio. That dilutes the degraded or additive-depleted polymer with good material so you can maintain the material properties and performance.

    • If you print a variety of different colors, and don't want all your recycled filament to mix and end up a muddy brownish color, it can be difficult to manage the color sorting and matching. Most people don't want different colors along the length of a spool, either. So the regrind has to be mixed evenly in with virgin pellets and a suitable amount of masterbatch colorant to get a reasonable color output. You're not going to run off a new spool with 95% virgin pellets just to recycle a 50 gram failed print, are you? Likewise for material matching. Mixing materials is a bad idea. If you only print white PLA, this is all pretty easy to manage. But if you print a variety of colors and materials, you've got to set up a material tracking, sorting, and storage operation. You can do it... it's just a hassle.

    • Diameter control is difficult. 3D printers need a fairly tight diameter control for reliable performance and good quality. This is really the key challenge in any filament extrusion process. Extruded polymers like to change shape as they extrude and cool due to molecular alignment effects. You can't just push molten plastic out a 1.75mm nozzle -- "die swell" will make the extrudate bulge to a larger diameter immediately upon exiting the nozzle. Then you have to actually pull on the soft filament as it cools to carefully draw it down to the right diameter. The way the filament extruder measures diameter and controls tension is the key to getting acceptable results. Most hobbyist/desktop filament extruders have not succeeded at this.

    Those are just the major issues. Filament extrusion is a complex subject with a lot of depth. For a home user of 3d printers, making filament basically becomes a whole second hobby. In my opinion, it only really makes sense in a commercial production printing environment where paid technicians can run the extruder(s) and a very large print throughput makes the pellets+regrind economics much more favorable than just buying new filament.

    Reducing and reusing are preferable to recycling. Making your printer more reliable and gaining experience with calibration/configuration will reduce the volume of waste produced.

    There are also some productive uses that let you reuse unwanted prints as-is or "downcycle" them for productive uses.

    • I personally keep a box of failed prints (and calibration prints and
      no-longer-needed prototypes) as showpieces for people who want to
      learn about 3D printing, and as toys for my nieces and nephews. I strongly recommend doing your calibration prints with a "toy" calibration model like Benchy or CaliBlocks. 3D printing is still new enough that people will happily take dozens of Benchies off your hands for the novelty value.

    • Failed and unwanted prints can also be used around the workshop for shims, sacrificial
      cushions when clamping or hammering or drilling, or as scrap for experimenting
      with adhesives or post-processing techniques.

    • ABS scraps are good for making ABS-slurry as a print bed adhesion treatment
      layer, or for solvent-painting and filling gaps in other prints. Unfortunately, most other filaments do not have such convenient and safe solvents.

    • Some people have experimented with putting piles of scrap prints on a cookie sheet in an oven and melting them into multicolor cutting boards. There's a lot you can do with this sort of heavy remelt plate if you get creative. (I personally wouldn't use cheap Asian filaments for food contact though, they often have unpleasant contaminants.)

    I like your idea of melting scrap parts down into a cutting board. Do you have a link to somewhere that mentions this? I'd do that but want to avoid destroying my oven or cookie sheet.

    Hmm, I saw somebody post about it on a forum a couple years ago, can't find a link, sorry. I would assume you cover the cookie sheet with something non-stick (maybe aluminum foil or a silicone baking mat) or use a teflon non-stick sheet, and heat the oven to something resembling 200C/400F. I would also put a little aluminum foil tent over the plastic so you don't get hot spots from the heater elements. Preheat well and leave it in the minimum time to melt into a puddle. Keep a fire extinguisher handy and let us know if you try it :-)

    Might be best to try it outside in a cheap toaster oven before using your kitchen oven.

    This may be what Ryan Carlyle was referring to https://www.youtube.com/watch?v=G-HWrDMr0ks

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Content dated before 7/24/2021 11:53 AM