<p>With <a href="/questions/tagged/fdm" class="post-tag" title="show questions tagged &#39;fdm&#39;" rel="tag">fdm</a> printers, the 3D object that should be printed can be positioned anywhere in the build volume. But it's only practical to place it on the bottom, because otherwise support material would be necessary.</p>

<p>stereolithography has the same problem. Even though the photopolymer can be cured at any position in the build volume, the result would drift away if it was not held in place by support material.</p>

<p>The powderbed based printers (either powder+binder or any of the laser/electron beam sintering/melting variants) do not have this problem, because they continuously fill the entire build volume with powder. The support material that other printing technologies require is part of the powder based printing anyway. It would be possible to pack the build volume with many prints and print them in one go.</p>

<p>Given that the machines are relatively expensive, it would be economical to increase the throughput. A company that does use such printers heavily could wait a certain amount of time until a few print queued up that fit together in the build volume and only then start the process. Do people do this?</p>

[{'answer_id': 272, 'author': 'tjb1', 'author_id': 233, 'author_profile': 'https://3dprinting.stackexchange.com/users/233', 'pm_score': 5, 'selected': True, 'text': '<p>There are several things you could try without spending much but even PLA will warp on an unheated bed.  I had a Legacy Kossel that I switched to an acrylic bed and had many issues with warping and prints pulling off the bed.  </p>\n\n<p>Some cheap things to try would be...</p>\n\n<ol>\n<li>Adding a brim to the print.</li>\n<li>Blue painters tape on the acrylic, remove the other material if doing this.</li>\n<li>Place cheap piece of glass/mirror on bed and use hairspray/gluestick.</li>\n<li>Use hairspray/gluestick directly on acrylic.  You must be careful here because first layer height is very critical to prevent damage to the acrylic from the plastic welding.  A layer of hairspray or glue should prevent it but dial in your height before printing.</li>\n<li>If you aren\'t currently using a fan, you could try sealing the sides to prevent drafts.  I doubt this would change much since you are using PLA but it\'s an option.</li>\n<li>If these are your designs, there are steps you can take to reduce warping as seen <a href="http://hackaday.com/2011/11/15/a-technique-to-avoid-warping-on-large-3d-prints/">here.</a></li>\n</ol>\n\n<p>Also many other suggestions <a href="http://www.makerbot.com/blog/2011/06/23/12-ways-to-fight-warping-and-curling">here.</a></p>\n'}, {'answer_id': 306, 'author': 'Dimitri Modderman', 'author_id': 264, 'author_profile': 'https://3dprinting.stackexchange.com/users/264', 'pm_score': 2, 'selected': False, 'text': '<p>I use 3DLAC from Reprapworld on a heated bed. People I meet once a month during our 3D Printer meets use this stuff on non-heated beds.</p>\n\n<p>I suspect it is just hairspray, but for me it did miracles. Especially printing large objects that go all the way up to the edge.</p>\n'}, {'answer_id': 10365, 'author': 'markm46', 'author_id': 16788, 'author_profile': 'https://3dprinting.stackexchange.com/users/16788', 'pm_score': 0, 'selected': False, 'text': "<p>Try a dilute solution of PVA glue (approx. 5:1 water:PVA) applied to the bed or the BuildTak like sheet and allowed to dry. \nKeep the ambient temperature as high as possible (but not so high as to soften any plastic on the printer obviously). \nBig brims help - consider adding them to the model rather than just applying them in the slicer. I've used 12&nbsp;mm by 0.5&nbsp;mm deep circles to good effect, particularly on acutely angled parts of the model or the extremities.</p>\n"}]
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