What Is PHA, and Could It Be the Most Sustainable Material for 3D Printing?

I believe this type of material is incredibly important for the 3D printing community. One reason is that we often need support structures to print complex objects, and all of that material ends up as waste, along with brims, test prints and failed prints.

Many people are looking into recycling: shredding old prints and extruding new filament. But that process is full of challenges and is not as straightforward as it sounds. Even when it works, it requires an investment that might be fine for a large studio. For a small creator with only one printer, it is often not economical.

That's why I'm so interested in PHA. It is 100% bio-based and biodegradable in almost any natural environment. But before we dive deeper, let's look at the most popular material in our community: PLA.

PLA needs the heat of an industrial composting facility, around 50–65 °C, to break down within weeks. In soil the same process can take years, and studies in seawater have found little to no degradation (Catarci Carteny & Blust, 2021).

While PLA is bio-based, it is only truly biodegradable in industrial composting facilities. In nature, there isn't much research proving it breaks down quickly; it will likely stay in the environment for a very long time. And many regions don't have the collection systems or composting infrastructure to handle it anyway.

Bio-based tells you where a material comes from. Biodegradable tells you where it can go at the end of its life. PLA is the first, but only partly the second.

Unlike traditional plastics made from fossil fuels, PHA is created through a natural fermentation process.

I think PHA is a far better material than PLA in terms of both characteristics and sustainability. To see why, it helps to look at how it's made.

Producers feed microorganisms, like bacteria, natural sugars and oils, and the bacteria store PHA inside their cells as an energy reserve. It works almost like “bacteria fat,” as colorFabb puts it. That PHA is then extracted and processed into pellets and filament.

Because it is 100% natural, PHA is a truly circular material:

1. 1Plants provide the sugars and oils.
2. 2Bacteria turn them into PHA and store it in their cells.
3. 3The PHA is extracted and made into filament.
4. 4We print a product and use it.
5. 5At the end of its life, microorganisms eat the PHA again and break it down into CO₂ and water.
6. 6Plants take up that CO₂, and the cycle starts again.

When you're done with a product, microorganisms can eat it again, breaking it down into CO₂, water and biomass. According to colorFabb, allPHA does this without leaving microplastics behind.

It doesn't happen overnight, though. The speed depends on the thickness of the part, temperature, moisture and microbial activity. A meta-study of marine research estimated that a PHA water bottle takes 1.5 to 3.5 years to fully biodegrade in the ocean (Dilkes-Hoffman et al., 2019). Cold water slows it down: in a six-month test in a simulated temperate sea, PHA films showed only early weathering (Catarci Carteny & Blust, 2021).

For me, that's the real advantage: if a PHA part ends up in nature, it can actually return to nature. That's no excuse to throw prints away, but it's a far better worst case than PLA.

I 3D printed this lampshade using allPHA from colorFabb. The printing process isn't as easy as using PLA. The material is sensitive to warping during the print, so using a brim and glue is necessary for good bed adhesion.

Another major difference is that there is no need for a heated bed. I set the bed temperature to 0 °C, which simply means the heater stays off. That sounds strange, but it's what PHA needs: a heated plate triggers crystallization in the first layers, and that leads to warping. As a bonus, a cold bed saves energy on every print.

Also, the printing speed is much lower than PLA. To compensate for that slower speed, I used a 0.8 mm nozzle for this lampshade. A wider nozzle puts down more material with every pass, so the print finishes sooner, even at a low speed.

Recommended PHA print settings

• Nozzle temperature

  Starting point

  190–200 °C

  Notes

  Start mid-range and adjust for your hotend

• Bed temperature

  Starting point

  Cold, heater off

  Notes

  A heated bed triggers crystallization and warps the first layers

• Bed adhesion

  Starting point

  Adhesive (3DLac spray or diluted wood glue) and a brim

  Notes

  colorFabb uses about 20 brim lines to keep corners from lifting

• Part cooling fan

  Starting point

  100%, from layer 2 or 3

  Notes

  Removing heat fast keeps crystallization under control

• Print speed

  Starting point

  40–80 mm/s

  Notes

  Much slower than PLA; a 0.8 mm nozzle helps make up the time

• Retraction

  Starting point

  A bit lower than for PLA

  Notes

  Small gaps in the outer wall mean retraction is too high

• Drying

  Starting point

  Not needed

  Notes

  PHA doesn't attract much water

Starting points from colorFabb's allPHA print settings and technical data sheet. Fine-tune them for your printer.

While the process is slightly difficult, I think this material has great potential. It is very tough and can withstand temperatures of over 120 °C without deforming. colorFabb's data sheet lists a heat deflection temperature (HDT) of 153 °C for allPHA, and the company reports excellent layer-to-layer adhesion.

For lamps, that's a big deal. PLA starts to soften at around 44–60 °C, so PHA gives you much more headroom near a light source. Whatever material you print with, use an LED bulb: it runs far cooler than halogen or incandescent.

• Made from

  PHA (colorFabb allPHA)

  Sugars and oils fermented by bacteria; 100% bio-based

  PLA

  Fermented plant sugars, such as corn; bio-based

• Where it biodegrades

  PHA (colorFabb allPHA)

  Soil, fresh water and the ocean

  PLA

  Industrial composting only, at about 50–65 °C

• Time to biodegrade

  PHA (colorFabb allPHA)

  Months to a few years; about 1.5–3.5 years for a bottle at sea

  PLA

  Weeks in industrial compost; years or longer in nature

• Heat resistance

  PHA (colorFabb allPHA)

  Stable above 120 °C (HDT 153 °C)

  PLA

  Softens at about 44–60 °C

• Print bed

  PHA (colorFabb allPHA)

  Cold, heater off

  PLA

  Heated

• Print speed

  PHA (colorFabb allPHA)

  40–80 mm/s

  PLA

  Much faster on modern printers

• Ease of printing

  PHA (colorFabb allPHA)

  Harder: warps, needs glue and a brim

  PLA

  Easy and forgiving

It is 100% bio-based, and unlike PLA it can break down in soil, fresh water and the ocean.

The trade-offs are real. It's slower and fussier to print, and it costs more to produce than PLA (Catarci Carteny & Blust, 2021). But for a piece like a lamp, which you print once and keep for years, I think that trade is worth it.

If you want to 3D print this lamp, you can get the files at e-leora.com. Every design in the Leora library comes as STL, OBJ and 3MF files, with 3MF projects ready for Bambu Studio and OrcaSlicer, and detailed printing instructions for every model. It also comes with a commercial license option, so you can print and sell the lamps you make (see licenses).

Let me know what you think about PHA and what else you'd like to learn about the 3D printing process! Leave a comment on the video or send us a message.