Tips & Tricks: Designing For Interlocking Metals

Discussion in 'Materials' started by katkinkead, Aug 23, 2016.

  1. katkinkead
    katkinkead Well-Known Member
    INTERLOCKING METAL TIPS & TRICKS

    TOLERANCE FOR INTERLOCKING METAL PARTS

    While many of our materials have the ability to print interlocking, it is important to keep in mind that our interlocking metal has a tolerance that is higher than most. As stated on the material guidelines page, the distance between interlocking metal parts is a minimum of 1mm.


    [​IMG]
    Note: The tolerance between parts in our Strong & Flexible materials is .5mm . You may need to make adjustments to models that you have already printed in Strong & Flexible.

    MINIMUM WIRE THICKNESS FOR INTERLOCKING METALS

    Due to the excess handling during the interlocking metals processing, the minimum wire thickness is 1.5mm.

    [​IMG]

    It is important to keep this in mind while designing, as it deviates from the minimum wire thickness of our non-interlocking metals. Design guidelines for both can be found on our materials page.


    UP TO SIX INTERLOCKING PARTS

    While the illustrations in this the examples below show 2-3 parts per model, you can actually have up to six interlocking parts within your model.

    [​IMG]


    ORIENTING SHELLS FOR BOUNDING BOX

    The nature of interlocking metals means that you will have multiple interlocking shells that make up your design. Whether it is a chain or pendant link, you will want to make the most out of your design by adjusting parts within your model to fit the bounding box for interlocking metal. Remember, the bounding box for interlocking metals is 75 x 75 x 40 mm.

    In the example below, we have interlocking parts that are aligned vertically on top of one another. While this may be the most obvious way to design your model, it is not necessarily ideal for upload. In this case, the vertically aligned model would be too large for the interlocking metal bounding box.


    [​IMG]


    While this version of the model may be rejected, there is a way to edit your model to fit the bounding box without sacrificing any quality. Simply re-adjusting the orientation of a few parts will change the bounding box of your model, and make it qualify for the interlocking metal bounding box.

    [​IMG]

    CONSOLIDATING SHELLS FOR BOUNDING BOX

    Once again, when creating parts for interlocking metal, the most obvious way to design your product is not always the optimal way to upload it. In the example below, we have two vertically intersecting chain hoops. As you can see, the first set of hoops in the illustration are oriented so the endpoints are far from one another. Quickly adjusting the placement of the bottom hoop optimizes the size of the model, making it ideal for printing.

    [​IMG]

    ----------

    That's it for my tips on designing with interlocking metals! Have anything else you'd like to add? Please comment below with any questions or suggestions!
     
    Last edited by a moderator: Feb 27, 2017
    mirco_ and cindyteng like this.
  2. mkroeker
    mkroeker Well-Known Member
    Minor nit: the limitation to 6 segments maximum is not mentioned on the redesigned material page for brass.
    (And the layout is getting a bit crammed, silver in particular. Might have been better to keep a separate page for the interlocking ones and link to that from the "interlocking and enclosed" section of each metal page. )
     
  3. bgeorgakas
    bgeorgakas Well-Known Member
    Thanks @mkroeker . The brass material page has been updated to show the maximum of 6 parts restriction.

    We'll explore improvements to the layout for future :).
     
  4. Digitallake
    Digitallake Member
    Newbie question... Do we have to design/3d model the placement of sprue??
    thanks!
     
  5. UniverseBecoming
    UniverseBecoming Well-Known Member
    No. That is something that is done by Shapeways both for the interlocking and also the regular non-interlocking 3D printing. One thing to keep in mind when designing for interlocking is, there needs to be ways that sprues can be attached and also removed. They are removed by first cutting with a cutter similar to a pair of dikes and then the sprue is also ground down to the part surface with a rotary tool. So room is needed to remove the sprues.
     
    mirco_ likes this.
  6. frankxie
    frankxie Member

    so the sprues are added after the wax model is printed?
     
  7. frankxie
    frankxie Member
    2 newbie questions:
    why interlocking is not supported on premium silver?
    and why the bounding box is different from the regular silver?
     
  8. UniverseBecoming
    UniverseBecoming Well-Known Member
    Good questions.

    so the sprues are added after the wax model is printed? I don't know exactly how Shapeways is doing it. Traditionally sprues are added after the print because they are so easy to add. It's just a matter of heating the end of a wax rod 1 to 4 mm in diameter and then touching it to the wax model. If the sprues were designed in CAD there would be a lot more control of the geometry of the sprues, but this also entails using more 3D printing material which tends to be on the expensive side. Shapeways may not say how they do it because Shapeways tends to be secretive about how they do things behind the scenes. For example, how Shapeways makes their ceramic material is a complete secret. They also won't say what 3D printing machines they are using for their FDM material. Trade secrets. :)

    why interlocking is not supported on premium silver? I don't know for certain, maybe a Shapeways employee will see this and respond. I'm thinking it is because their premium silver is polished by hand while their regular polished silver is done by mass finishing. Mass finishing involves the use of something like a vibratory finisher that can handle thousands of parts at a time and it would be easier to do interlocking parts in this way. Whereas, hand finishing involves having to hold the piece in your hands while moving it over some kind of grinding or polishing tool. Interlocking parts would be hard to do this way for certain types of geometry situations because they could be difficult to hold on to them.

    and why the bounding box is different from the regular silver? I don't know for certain but it may be because they need the extra room for all the extra sprues.
     
  9. mkroeker
    mkroeker Well-Known Member
    Now the tighter bounding box for interlocking appears to be applied to non-interlocking metals (except premium silver that has no interlocking counterpart) as well. How about changing the release cycles so that disruptive changes are made on tuesday rather than thursday, giving developers less chance to go into hiding for two days as the bugs pop up ?

    Sorry about that entirely inappropriate rant - I had mixed up models myself, everything is alright once I managed to sort myself out. (Though now I wonder why that model was not refused for premium silver as well - it was interlocking as it turns out and I really should know as I made that model some time ago to demonstrate the fact. Guess premium silver did not receive an improved checking function in last thursday's entirely correct release)
     
    Last edited: Aug 27, 2016
  10. UniverseBecoming
    UniverseBecoming Well-Known Member
    It was a good rant attempt. :p
     
  11. Gatekeeper1
    Gatekeeper1 Member
    Very interested in this new prosses. I'm looking at making a pending that would be made of two places the center ring is silver while the outside is bronze. would it be possible to cast the two materials so that the silver is interlocking with the inside of the bronze?

    From the video description of how it's done, they said something about separating the interlocking parts with a screw? Does that mean that there are technically two points that the model is poured from? Because two points of entry for two interlocking pieces should also give us the ability to use two different metals that are interlocked with each other (and that would be super ultra cool) Just an idea.
     
  12. mkroeker
    mkroeker Well-Known Member
    "Sprue" not "screw" - they are adding small sticks to the model to join the parts together for casting, and cut them out afterwards. While pouring is probably done from more than one point if the model geometry requires it (regardless if it is interlocking or just a single part), this is not a multi-material process.
     
  13. Gatekeeper1
    Gatekeeper1 Member
    Ah, Thaks for the clarification. :) I still wonder if you could use the multiple pouring ports and addition of the spure to design a separation between the different material. But maybe I'll have to work that one out myself. ;)
     
  14. mkroeker
    mkroeker Well-Known Member
    I guess one could in theory (but I am not a caster). Pretty certain it would mess up their process - now interlocking metal is exactly the same as non-interlocking from the caster's perspective (all the sprueing and un-sprueing to make interlocking possible happens outside the casting regime) so they can build trees of tens of small individual models that they cast in one pour. Also I have no idea what happens temperature-wise when a second metal is poured into a mold that already contains a solidifying cast - would this cause irregularities or weak points in the cast ? Lastly one would probably also have to look at the combination of metals or alloys that would have to meet somewhere in the middle of a sprue - one probably would not want combinations that are capable of forming new alloys or intermetallic compounds, possibly with a sudden increase in volume...
     
  15. scarcamo
    scarcamo Member
    How is this process done? (in terms of how interlocks print)
     
  16. merecreation
    merecreation Member
    It was said above that there needs to be 1mm distance between interlocking parts. Imagine a cube inside an open box. Does 1mm distance mean that the distance between the outer wall of the inner cube and the inner wall of the outer box need to be at least 0.5mm on either side of the smaller cube, such that when the smaller cube is pushed to one side, the distance between the walls is 1mm?
     
  17. merecreation
    merecreation Member
    And, if the maximum number of interlocking parts is 6. How did this person () create 13 interlocking cubes? Go to minute 8:07.