<p>Googling 'HDPLA' has so far availed me very little. </p>

<p><a href="http://3dinsider.com/what-is-pla/" rel="nofollow noreferrer">http://3dinsider.com/what-is-pla/</a> indicates that /all/ modern PLA is 'high density' compared to 'the early days'. But a fellow at the local makerspace indicated that he was specifically using 'HDPLA', with [he claimed] markedly better properties than regular PLA in the final product.</p>

<p>A company named Florion claims to have some secret sauce they add to their PLA, and Maker Filament touts a high temp PLA; but neither seems to use the 'HD' prefix.</p>

<p>I haven't yet been able to track down the fellow to get any more specifics from him. There's no reel of the stuff sitting around so I can't look at its labeling for clues. He claimed to be fabbing lab fittings but I don't know the intended operating situation/requirements. </p>

<p>It's possible he meant something else, like HDPE, which would be quite inert and thus a good choice for lab fittings--but I'd like to think that if it was lab equipment he was making he'd get the name of the polymer right.</p>

<p>Comments, including any regarding the Florion or Maker Filament or any other 'high performance' PLAs, would be most welcome.</p>

[{'answer_id': 5272, 'author': 'Mick', 'author_id': 3953, 'author_profile': 'https://3dprinting.stackexchange.com/users/3953', 'pm_score': 0, 'selected': False, 'text': '<p>I doubt that it means very much at all. Filament manufacturers are very tight-lipped about the co-polymers that they add to their base stock in order to improve handling and performance characteristics, so it is impossible to say. The only common attribute that I can see is an advertised diameter tolerance of &plusmn;0.02mm. Maybe HD stands for <em>high-definition</em>, rather than <em>high-density</em>?</p>\n'}, {'answer_id': 5289, 'author': 'mac', 'author_id': 9134, 'author_profile': 'https://3dprinting.stackexchange.com/users/9134', 'pm_score': 2, 'selected': False, 'text': '<p>So, low-teck, old-style investigative work from my side.... I contacted <a href="http://www.filright.com" rel="nofollow noreferrer">a company</a> selling HDPLA and they got back to me with the following reply.</p>\n\n<blockquote>\n  <p>We created HDPLA as an industrial PLA with special additives. As a result, our so called HDPLA has the advantages of ABS, but prints as easy as regular PLA.  HDPLA has high impact, high strength and high heat deflection temperature (hdt). You can also print at high speed (max 140mm/s inhouse tests).  HDPLA has is own high strength, but is even more strong after annealing.  A heated bed is not necessary (50-60˚C recommended), and you can print with HDPLA with a 3D printer with open structure.</p>\n</blockquote>\n\n<p>This is strikingly similar to the <a href="https://www.3dprima.com/filaments/primaselect-pla-pro-1-75mm-750-g-black/a-22432/" rel="nofollow noreferrer">description of what 3Dprima calls "Prima SELECT PRO"</a>:</p>\n\n<blockquote>\n  <p>PrimaSelect™ PLA PRO ist the next generation of high performance PLA for demanding industrial applications. Designed to be able to print fast >120mm/s so you can save on production time. Very high heat resistance (95°C+) after annealing. Excellent mechanical properties combined with a matte surface finish that helps concealing the printed layers for optimum appearance.</p>\n</blockquote>\n\n<p>While writing this answer I also found <a href="http://fiberlogy.com/en/fiberlogy-filaments/filament-hd-pla/" rel="nofollow noreferrer">a page</a> that escaped my googling until now, sating an additional property of "their" HDPLA: food safety.</p>\n\n<blockquote>\n  <p>With our HD PLA you have many more options. You can use this material in two ways. Choose the one you like best. You can use it as a normal PLA and get prints characterized by a very good adhesion between the layers and high precision. You can also make your prints acquire similar properties to that of ABS – better impact resistance and high temperature resistance. All you need is an oven. Yes, an oven! By annealing our HD PLA in an oven, in accordance with the manual, you will avoid all the inconveniences of printing with ABS, such as unpleasant odour or hazardous fumes. But these are not all the advantages of HD PLA. For the production of this material we have chosen raw materials that are approved for food contact in compliance with the EU directive and FDA regulations. HD PLA is also certified by RoHS.</p>\n</blockquote>\n\n<p>So, it looks like HDPLA is not the shorthand of a polymer molecule, but rather <strong>a trade word indicating that the base PLA has been mixed with additives</strong>.  Furthermore, the answer I got via mail seems to indicate that <strong>"HD" refers to the high <em>Heat Deflection</em> temperature</strong> of the filament (the <a href="https://en.wikipedia.org/wiki/Heat_deflection_temperature" rel="nofollow noreferrer">heat deflection temperature</a> is the temperature at which a polymer or plastic sample deforms under a specified load).</p>\n'}]
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