High-Temp Printer - Blows heated air on print?

  • I saw this video from Robotdigg and thought it was interesting.

    I'm trying to piece together how the printer works. It is not enclosed and the heated bed only reaches 120C.

    They print a part in PEEK using an ooze shield and show adjustment of some fan speed during the print. My guess is that they blow hot air on the part, but there's no mention of this in the video or on the product page.

    RobotDigg HT Printer

    It's clear that they are printing the PEEK in such a way that the crystallinity is low which probably helps a lot with the warping. The part is also pretty small.

    even if they aren't using a hot air blower, does anyone think that would be a viable method for printing high-temp polymers?

  • Moderator

    I have seen hot air blowers used before as well. Doing some googling should turn some more examples up.

  • So long as you are only printing small parts its a viable thing.

    Although it might still have value on larger parts, if you can bring up the temp of the prior layer with the hot-air jet it will help with inter-layer bonding.

    I've done the most experimental printing with Ultem, where the issue is keeping the delta between the prior layer and new layer as small as possible. Otherwise it delaminates. Once you get big enough, then controlling ambient build volume temp becomes a bigger issue.

    Its certainly easier to blow a small jet of very hot air than heat the entire build volume.
    That jet of air probably needs to be 200-350C...

  • @theruttmeister

    If you have a well insulated enclosure then it's much more efficient to heat it up once and keep it at set temperature. Instead of constantly blowing hot air and fighting against the significantly colder ambient. It's stupidly inefficient.

    The longer the print time. The more inefficient it is.

    PEEK is notoriously hard to print. Even on high end machines so I'll believe it when I see it. Especially on usable parts. Also PEEK parts should usually be removed hot and annealed straight away. Letting it cool first is much more likely to warp.

    I'm a little skeptical about that being PEEK though.

  • @roiki11

    Oh I agree that its much more efficient to have a well insulated enclosure... but running a 150C+ enclosure is not simple, its non-trivial in both engineering and IP. A hot air jet at the nozzle might be just enough that you can print small objects.
    Its going to heat your workshop up though!

    And I've printed PEEK, its more difficult than Ultem1000 which is already a real pain. Building a machine to do either is... not simple.

    And unless PEEK has changed recently, that video is Ultem (PEEK is opaque, the polymer in the video is translucent).

    I keep seeing companies promote machines that can print in Ultem and PEEK, and I'm still sceptical that any of them can do it well or reliably.

    Besides, once someone builds a machine that can reliably print in PEEK and Ultem, people will start asking about Extem.

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