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    Automated process to trim and finish clear aligners

    Discussion in 'Orthodontics' started by perfectalign, Feb 17, 2014.

    1. perfectalign

      perfectalign New Member

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      Hi,

      Is there anyone that knows a setup for trimming and finishing clear aligners onces they have been thermoformed on printed models? Maybe with CNC or laser equipment. There needs to be a predefined cutting line I guess that is 2mm above the gingiva.

      Hope to hear thanks!

      Jesse
      http://www.perfectalign.com
       
    2. rkm rdt
      Artistic

      rkm rdt Well-Known Member Donator Full Member

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      Why not make the base stop at desired length of the aligner and slice the material off at that line?

      Why do you have to print past the aligner?
       
    3. CoolHandLuke
      Fiendish

      CoolHandLuke Well-Known Member Full Member

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      i would guess you do, to demonstrate that you finished it 2mm above the ging.

      seems pretty redundant to me though.


      i would think you can trick modelbuilder into creating a pretty tiny model, and then use that as a suckdown guide, and just hot knife it.
       
    4. rkm rdt
      Artistic

      rkm rdt Well-Known Member Donator Full Member

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      exactly
       
    5. Teofil

      Teofil Member

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      Hey
      I produce aligners using 3D. There are a few things you need to consider.
      First of all, printed models have to have a flat base however "tiny" you print them. You can't thermoform if it's not stable or has undercuts. Since not all teeth are always at equal height their "neck lines" height also differ. You can't cut aligners following exact neck-line since every sharp angle will be a week spot and aligner will most likely break. The proper way to cut aligners is following a contour line 1mm above neck-line, with no sharp angles.
      I assume you would like to automatize the part of a process after you use your pressure thermo forming machine like Biostar or similar. To do this you need 3 axis CNC mill. CNC mill "feeds"on numerical code provided by the software , i tells the burs and model holder where to move relevant to each other in space.
      The main problem with this is that you can not use the same cutting path for different patient since every jaw(set of models) is unique. The cutting path is drawn in cnc router software, but you have to keep in mind that this line's position in 3D space has to be set in relation to the edge of blank thermoplastic sheet. Also because of this every 3D printed model in the whole set of models has to be set on precisely same position on the forming platform.
      If you don't understand what I'm trying to say I can make you a crude drawing since my technical drawing skills are pathetic :)
       
      • Agree Agree x 1
    6. rkm rdt
      Artistic

      rkm rdt Well-Known Member Donator Full Member

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      Models can be printed with a porous material to improve vacuum forming.
       
    7. Betalab

      Betalab Member

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      Hey Jesse, your web site shows awesome aligners, how did you get those? How did you finish them? Have you seen " clear corrects" YouTube video.?
      It shows from virtual setup to model printing to thermo form to cutting. I can appreciate that gingival heights are different and hence its not as simple a straight cutting or manipulating model builder.
      Tell me what you find out plz :) Patrick
       
    8. sriraman thiyagarajan

      sriraman thiyagarajan New Member

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      Hi....,

      Is there any specific brand CNC milling machine is there...? Or we have to customize it...? Kindly elaborate... Because i am struggling so much in this regards....
       
    9. JKraver
      Tired

      JKraver Well-Known Member Full Member

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      This seems like more work and time than the conventional method.
       

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