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SLS - Design Tips

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L
5

Good evening,

As part of a project for my Mechanical Engineering degree, I am working on the task of “Implementing 3D printed parts in production”. I have already gained some experience with FDM printing, but unfortunately not in the SLS area.
The component I am dealing with should be optimized for printing. Now the component is clamped with two M8 countersunk screws. Unlike metal, plastic can creep under continuous load (especially at increasing temperatures), so the tightening torque of the screw decreases. Is creep to be expected with common SLS powders (e.g. PA12/PA11/iglidur i6)? — So, would one have to insert a metal sleeve for relief?

Thanks in advance!

Automatically translated from: Deutsch
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Solved by Tilmann98

I think a general recommendation can be to test your SLS parts under the given conditions, as there are many physical factors that can influence these. But all in all, SLS PA12/PA11 under the conditions you specified is a really good alternative to, for example, FDM ABS/Nylon/PLA.

    • L
      Good evening,

      As part of a project for my Mechanical Engineering degree, I am working on the task of “Implementing 3D printed parts in production”. I have already gained some experience with FDM printing, but unfortunately not in the SLS area.
      The component I am dealing with should be optimized for printing. Now the component is clamped with two M8 countersunk screws. Unlike metal, plastic can creep under continuous load (especially at increasing temperatures), so the tightening torque of the screw decreases. Is creep to be expected with common SLS powders (e.g. PA12/PA11/iglidur i6)? — So, would one have to insert a metal sleeve for relief?

      Thanks in advance!

      Automatically translated from: Deutsch

      See original
      0
    • T

      How is the component clamped with the M8 countersunk screws? Through the threads, which are inserted into the component?

      0
      Reply
    • What are the approximate operating temperatures? In general, the temperature does not play a major role if it does not exceed, for example, 70 C (PA12). Creep can of course be taken into account, but it depends on the applied load.

      p.s. I found this video from Xometry. It’s not exactly your case, but it helps to get a sense of how different 3D printing technologies and materials (including PA12) behave under comparable conditions.

      0
      Reply
    • L

      All clear, thank you very much. The screws are screwed into a stainless steel plate below – the plastic part is clamped between the screw head and the plate (I would have a screenshot, but unfortunately I can’t insert it)
      The operating temperatures vary between 5° and 60°, although most of the time there is room temperature.

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      • T
        Luca

        I think a general recommendation can be to test your SLS parts under the given conditions, as there are many physical factors that can influence these. But all in all, SLS PA12/PA11 under the conditions you specified is a really good alternative to, for example, FDM ABS/Nylon/PLA.

        0
        Reply
    • Xometry Engineer

      Hello Luca,

      I can only agree with Tilmann 98 here. SLS parts are generally of high quality and have a density of almost one in PA12, in MJF also above one. The difference is about 10%. Another possibility to minimize creep would be PA12GF (glass filled). This PA12 has a 30% glass content and is harder, but then tends to break more quickly if excessive forces are applied.

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