Heat Treating Aromatic Coffee High Temp PLA

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In a previous blog I tested the printing properties of Proto Pasta’s Conductive PLA and Aromatic Coffee PLA.
According to information from Proto Pasta, Aromatic Coffee Filament is a high temperature blend. Proto Pasta also provides a procedure to anneal it to be harder and more heat-resistant than normal PLA.
A high temperature PLA is appealing to 3D printers. Instead of dealing with the hassles of ABS, or the cost of Nylon filaments, a high temp PLA would appeal to 3D printers that are looking for an easy to print material for the kitchen.

Warped PLA - High Temp PLA
Standard PLA cookie cutters after warping in the dishwasher

This is an interesting property for PLA. In the past I put standard PLA cookie cutters on the top rack of the dishwasher, only to see them warp like crazy.

Testing – High Temp PLA

This print is problematic. - High Temp PLA
River Tam calling it like it is.

For this test I originally tried to 3D print 2 walnut leaf trivets. However, both times I tried printing the print failed. I was printing at 210 C through the hot end, and it seemed that there were a couple of spots in the filament that would not get up to temperature, resulting in a jam.

test spoons - High Temp PLA
3 printed rice spoons before heat treating

I switched to a smaller print, a rice spoon.  I was able to print one spoon at 210 C, but after another spoon failed to print, I had to bump the hot end temperature to 215 C. Even at this temp, I had moments where filament again jammed. Of course this happened while I was away from the printer for a moment, so I do not know if something else is causing this jamming.
I do not know why this batch of prints was so problematic compared to my previous test print.

To test the properties of annealed PLA, I followed the companies instructions to heat-treat its PLA for two spoons (210 C and 215 C), leaving the other (215 C) as the control.

How To Heat Treat High Temp PLA

According to Proto Pasta’s instructions,

“For maximum performance, your prints should be heat-treated (i.e. crystallized) in an oven until you see a change from translucent to opaque. Yes, there is an obvious visual change indicating the improved performance! We had good luck in a lab oven at 110C (230F) for an hour or less. We recommend leaving the supports on your parts, placing them on a non-radiating surface (like glass, ceramic, or composite), and letting them cool in the oven to minimize distortion. Parts can be baked at a lower temperature (though must be above 60C for any reaction) for a longer time with less risk of unwanted deformation.”

Before Heat Treating – High Temp PLA

Two spoons were printed at 215 C. The higher temperature gives them a smoother milky brown tone, compared to the banding I see in the spoon I printed at 210 C.

test spoons - High Temp PLA
3 printed rice spoons before heat treating. 215 C to heat-treat (top) 215 C control (middle) and 210 C (bottom)

For the comparison, I’ll use all three spoons.To see if heat treating changes the size, I recorded the measurements of the spoons in the table. All measurements in mm.

Spoon               |   Handle Width   |    Handle Length   |   Bowl Width   |    Bowl Length
210 C Pre treat   |   19.90                |   88.48                    |    44.80             |    71.80
210 C post treat |   18.74                 |   88.51                     |   44.76              |   69.72
215 C control      |   19.75                 |  88.51                      |   44.81              |   71.82
215 C Pre treat   |  19.75                  |   90.56                     |   40.81              |   71.81
215 C post treat |  18.75                   |  88.51                      |  45.78               |   68.71

Heat Treating – High Temp PLA

I put the 210 C and 215 C samples in a glass dish to heat-treat. I placed the samples in an oven preheated to 110 C (230 F). I then cooked them for an hour, with a half hour cool down time in the oven.

Heat treating spoons - High Temp PLA
Spoons cooking in the oven

The only change I noticed when I did this was the color. Previously the samples all had bands of light and dark brown. After heating, the samples both turned a uniform light brown compared to the control. The rough layer in one sample piece did shrink, and some hairs and bumps did shrink down as well.
Unlike the time I printed the spoon, my oven did not smell like coffee as it was treated. It also did not melt to the glass dish, though there was a slight film left behind in the dish.
After they were cool, I could not feel any difference in flexibility or strength between the control and heat-treated samples.

Size Difference – High Temp PLA

Both heat-treated samples shrunk .5 to 2 mm depending on the measurements. In the future I’d test with something like a test cube to get a better idea of how this filament changes directions.

Boiling Water Test – High Temp PLA

For this test I got a pot of tap water to a rolling boil. I then put a spoon in the water for a minute, and then took them out to see if they were flexible be squeezing them at the spoon bowl and handle.

testing spoons - High Temp PLA
Boil testing spoons

The control spoon was the most flexible, flexing about 4 mm at the bowl and about 2 mm at the handle.
The 215 C control spoon also lightened significantly in color to a more milky brown, while the heat-treated spoons retained their color.

Flex testing spoons - High Temp PLA
Flexing warm spoons

The heat-treated spoons were slightly less flexible than the control while hot. However, all three spoons became rigid quickly as they cooled.

Overall impressions – High Temp PLA

Heat treating made a small perceivable difference in the warm flexibility of the test samples. If you plan to use Aromatic Coffee PLA in your kitchen for things like stirring spoons or soup spoons, you may be able to justify the time it takes to heat-treat the material.

post test spoons - High Temp PLA
spoons after testing. 215 C control (Top) 210 C (middle) and 215 C heat-treated (bottom)

But for other uses, I can’t say it’s worth the time to heat-treat this filament. Being a high temperature PLA, you can use it as is for medium temperature applications. The heat treating may keep it rigid at higher temperatures, but not by much.

Wash is not impressed - High Temp PLA
The coffee filament is a bit hyped.

The appeal of Aromatic Coffee HTPLA is the novelty of your printer smelling like coffee as you print. As to the high temperature properties, It is more durable than standard PLA, which bodes well for it. As to its heat treatment, I can’t say it makes much difference at all.
If you buy Aromatic Coffee HTPLA, you’re paying the premium for the coffee smell and novelty value of the filament.

If you make filament and want me to review it, please contact me [email protected] or leave a comment in the section below.

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  1. Tom Baxter says

    Thank you for the review Stan. I am hoping to get some added durability from the annealing for a small statue I made for the back yard. I also had some issues printing with Proto-Pasta HTPLA. It kept jamming on me. Even though other batches from Proto-Pasta were fine. It was the only time I tried printing with the black color HTPLA so I chalked it up to that color and moved along.

  2. Justin Flugum says

    I would like to try heat treating but, I’m afraid to have the print be worthless afterward.

    1. Stan Baldwin says

      I did not find any real advantage in heat treating or annealing the test prints. If you have a real industrial need for heat treated PLA, you may be better off with ABS or some other high temp / strength material like PETG or carbon fiber.

  3. Richard Bynum says

    Great information. I have yet to print with PLA but have been reading up on all the reviews. Seems like there is always a catch when it comes to using PLA. I need to print with it to find out if I like it or not and if it’s worth it. I’m sure it’s not as bad as I’m thinking it is in my mind. haha

    1. Stan Baldwin says

      PLA is my standard filament. It is forgiving, low warp, and environmental friendly. New blends are coming out all the time, and filament companies are exploring many exotic blends with a PLA base.

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