Bake your PLA and have it outperform everything else! #Filaween

Turn your regular PLA into a performance plastic with this one weird trick!

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[ultrapowermae]

Thumbs up for going the scientific route, and including ordinary PLA in the heat treatment test. Unexpected results, that are usable indeed. #respect

[dirkvantroyen]

This XY shrinkage could be an interesting property if you want to heat-shrink a part around a metal part for example. No glue needed and better strength.

[tijn]

I recently reprinted the broken handle of my espresso machine (witch gets around 90 °C) with PLA. At the beginning i thought this was a bad choice because it became very soft the first time the espresso machine got hot. But after a couple of times heating and cooling down the espresso machine the PLA stays hard even if the machine is on for hours and the handle feels stronger then ever.

[BilbyDPtyLtd]

Hey Tom, great video. We have been working with Proto-Pasta High temp filaments a lot, and testing them and the annealing process. We found the High Temp carbon fibre needs longer than one hour...up to 4hrs in larger more dense parts. You can tell if it has annealed correctly because you get zero softening at 120 degrees. This rule also applies to their HT PLA. WE make parts that are part of a kit that sits on a hot plate at 110 degrees for hours and has zero warp or soften. We anneal these parts at 75 degrees for 4 hours to get the best results. I wonder if the slower, lower temperatures we use actually increase the effectiveness. Interestingly we also get zero shrinkage in any axis.

I will continue to examine this, and will let you know when our results are online

[fredpinczuk]

Any method of annealing will reduce induced stress within a material and affects its final dimension (shrinkage and expansion). We normally see this within the PET packaging industry. The most interesting part is the added strength, this would concur with the theory of crystalinity being promoted by the heating process. PLA was originally designed as a replacement resin for PET material (plastic water bottles) back in the late 90's (it failed miserably). The ability to injection mold and then blow stretch would require a fairly long molecular bond, and ability to crystallize. Now how far can it be crystalized? BTW. I left my Proto-Pasta CF parts on their raft on a heated bed up to 110 C. Simply made a small box to insulate them and left them for 2 hours. Reduced to 80C for one hour, and finally one last hour at 60C. This prevented the parts from wrapping.

[alang]

Shrinkage XY and expansion Z could be due to memory effects relating to each line of deposited filament attempting to return to a more circular cross section as it was in the nozzle.   Great work Tom.

[mindmending]

tried baking PLA few weeks back, parts were definitely stronger but it really only suitable for use on simple shapes, brackets etc..

[techgeek]

Awesome video! I absolutely love the whole idea, it has certainly increased the amount of information on the market for filaments by far and is sure to be a handy tool to makers everywhere! Thanks again Thomas!

[RAMII]

Awesome video. I'm going to try this with my PLA parts. Having the extra strength would be fantastic since PLA is my favorite material to print with. I would also like to see what different lengths of time do, and different methods of cooling, like tempering used for metals.

[alang]

Just baked a sample of Prusa PLA as supplied with the MK2 @ 110C for 15 minutes on a perfectly flat glass tile (preheated). The part was scrap because of design changes.  The test was to determine what level of warp it would get and if there was a progressive effect over time in 15 min steps.  After the first 15 minutes the warping affected the geometry so much that further steps were not needed.  Z change was +11% over 8mm and in the other planes it was -10.6% over 10mm and -8% over 70mm.  One long side had a central protrusion with an 8mm hole with its centre line on the side face, it suffered -11.4% reduction.  The part was complex having four other holes in it so it could be expected to warp in an irregular and unpredictable way.  The only thing to take away from the test is that longer stretches of parallel filament seem too shrink less than shorter stretches where the proportion of parallel to perpendicular runs is smaller.

[ThomR]

some things to try:
buy an oven thermometer that sits on the rack. Built- in thermometers are notoriously inaccurate.

fill a tray with corn starch, lay the pieces on that to bake them. It should even out the heat distribution. The uneven surface of the plate used in the video would play havoc with this. You could go further and continue by also covering the parts with more corn starch. I'd try at least 1 cm deep above and below.

[kurtownsj]

I gotta say I've been LOVING eSun's PLA Pro/PLA+ lately. For its relatively cheap price I've been astounded by its performance and layer bonding....and even if it's not "stronger" you can tell it's many times less brittle. Pieces that would ordinarily suddenly fail with breakage instead bend a tad. And it's a few bucks cheaper than regular hatchbox PLA on amazon. I've gone through two fulls spools of each and I like the eSun PLA+!

[Panurg]

any plastics that have seen some kind of warm passing through a nozzle (extruded parts, water bottle is prolly best example) will show this kind of behavior.
crystallisation and recrystallisation mainly cause the shrinkage. the problem with fillers can be, that they suffer from bad adhesion to the matrix due to shrinkage and then basically act as crack starting points rather than reinforcing the matrix and often have not much use. adding special linking-agents (particle-matrix), e.g. silanisation can compensate for this.

[goldenmath]

Brilliant Thomas, always fun to see a theory proven, I love your investigative approach

[timebandit]

I can say that the PLA parts i printed think it was back in 2012 on my first printer The Printrbot Simple and the parts are still going strong. with the pressure of the pool wall i thought it would break but it proved to be just the opposite. Even a year ago i printed parts to fix my wifes bumper on her SUV and they are still going strong. Gotta love PLA.

[Topblackbird]

First ever video I have seen from you, I am blown away. The depth of testing and production quality is amazing!

[TheMrBeaton]

Different strokes for different folks, I suppose. I get my best results printing in ABS and exposing the parts to a room temperature vapor chamber (fancy name for a polypropylene box - or a box of other materials impervious to acetone (HDPE, glass, etc.)) with a small Acetone reservoir. Just keep in mind to not expose the part for too long; if the vapor penetrates too far the part will deform as it releases the acetone (in my experience, depending on the size and anatomy of the part, <1 hour exposure and an estimated 24+ hours for the release process). I get astonishing results using this process. I haven't taken the "scientific" approach and measured differences in tensile strength, but it is without a shadow of a doubt stronger by a perceivable margin.

[myuserissunluffys]

I am currently interested in moving from ABS to PLA but need the temperature range offer by ABS, so your video was of great interest to me. Based on your input, I baked a PLA box, which is 86x95 mm and with a print height of 41 mm. Wall thickness is 3 mm. Unfortunately, the annealing process caused the box walls to warp and blister with the outer shell separating from the inner fill. However, by encapsulating the box in plaster of paris and annealing below the boiling point of water, to avoid the moist plaster from cracking, I was able to get a usable PLA box, with virtually no warping or blistering. It's dimensions were also very close to that specified in the design.

Given the lid is a flat 3 mm surface, all I had to do to avoid an warping was to cook it while still attached to my hair spray coated glass print plate. There was, however, a 0.6% shrinkage along the print surface x and y axis. Print height increased by 3%.

[kaneh]

I tested normal PLA and petg for a quad build and wasn't happy with either then heard or the tempered/ annealed PLA I gave that a try and is far superior. To get round the warping, when it's cooling a place a heavy object on the top and it flattens it back to normal so in the end it's only a little smaller than the original piece and the minor shrinkage is accounted for. End result is a far stronger and heat resistant quadcopter especially the arms

[jcoghill]

Thank you for including the shrinkage and expansion percentages.