Dimensional thermal test jig (for annealing)

prusaprinters

<p>This is a companion for <a href="https://www.thingiverse.com/thing:1982686">the dimensional calibration tool by LuckyPants</a>. It allows you to place up to 4 of those tools at a 45 degree angle in an oven (or other thermal test environment). I used to for testing how annealing my PLA based parts improves thermal resistance (i.e. can I put these parts in a hot car?). It allows you to use the weight of the part itself to exert a bending force on the middle of the part.</p> <p>I printed mine in MakerGeeks PETG, but the next time I need to print it I'll probably print it in PLA and then anneal it at 80C for 40 minutes. The PETG did not hold up to temperatures as well as I had hoped.</p> <p>In addition to this little jig. Here's my notes from my test:</p> <p>Samples (each sample was 20% gyroid infill, 0.20 layer height):</p> <ul> <li>Brown Solutech PLA (which is pretty crummy and I expected to do poorly - but it did better than expected!). </li> <li>Yellow MakerGeeks HTPLA</li> <li><p>Blue MakerGeeks PETG (this piece was not annealed)<br/> Test environment:</p> </li> <li><p>A steam oven Sous Vide mode allowed very fine control of temperature and slow heating/cooling</p> </li> <li>The PLA and HTPLA parts were annealed in a horizontal orientation in the oven at 80C for 30 minutes. The parts were placed initially in a cold oven, heated and then allowed to cool in the oven.</li> <li><p>The PLA/HTPLA and PETG test pieces were placed on the jig and heated in the oven at a series of temperatures. Each temperature was held for 30 minutes. The test temperatures: 50C, 60C, 70C, 75C, 80C, 90C<br/> Findings:</p> </li> <li><p>The HTPLA shrunk 1.7% in X &amp; Y and expanded 0.5% in Z during annealing</p> </li> <li>The PLA shrunk 3% in X &amp; Y and expanded 0.5% in Z during annealing</li> <li>The PETG started to droop very slightly at 60C, drooped to about a 15% angle by 70C, by 75C it was basically limp on the bottom of the test jig</li> <li>The PLA had very slight droop (1mm) by 70C, but otherwise resisted the heat just as well as the HTPLA</li> <li><p>The HTPLA had no droop at any of the temperatures<br/> Conclusions</p> </li> <li><p>PLA does almost as good as HTPLA if you don't mind the shrinkage</p> </li> <li>HTPLA shrinks a lot less in annealing than regular PLA</li> <li><p>Annealed PLA has better temperature resistance than non annealed PETG<br/> Possible further research:</p> </li> <li><p>Try higher temps - I stopped at 90C because that's what was easy to test in my oven (and I only needed my parts to survive in a super hot car - which the internet says is about 75C)</p> </li> </ul> <h3>Print instructions</h3><h3>Category: 3D Printing Tests Print Settings</h3> <p><strong>Printer Brand:</strong> Prusa</p> <p><strong>Printer:</strong> <a href="http://amzn.to/2rqZ6Uo">i3 MK3</a></p> <p><strong>Rafts:</strong> No</p> <p><strong>Infill:</strong> 20%</p> <p><strong>Filament:</strong> MakerGeeks PETG blue<br/> <strong>Notes:</strong></p> <p>If you want this part to last, I'd recommend printing in PLA and annealing that PLA in an oven.</p>