Why are my parts expensive

Discussion in 'Materials' started by 302580_deleted, Sep 30, 2013.

  1. I was wondering why every single part i design and upload is expensive even though the parts are small and are thin.
     
  2. TrainThingz
    TrainThingz Member
    Those parts don't look particularly small to me...

    Most of the cost of a Shapeways-made item is in the material used. Go to your item's "Edit Item" page - the VOLUME of your item will be there in CCs (cubic centimeters) . That's what you need to minimize to make it less expensive.
     
  3. The biggest piece is 2.5 inches tall and a maximum of an 1/8 inch thick but even with the cheapest material makes the piece, <a href="https://www.shapeways.com/model/1372396/spor-t-motor-mount.html?li=my-models&materialId=6" target="_blank"></a> , expensive. I've seen bigger parts on shapeways that are cheaper. It seems like the box that my piece would fit in is being used to calculate the volume.
     
    Last edited: Sep 30, 2013
  4. mkroeker
    mkroeker Well-Known Member
    You could easily calculate the cost of the bounding box of your part - all solid it would be around 400$ (you are basically building a brick by sticking tiny grains of sand together, so this is not going to be particularly cheap or efficient).

    Other motor mounts (such as the "Guan'Li Icon A5 Motor Mount" as listed in the "related items" when one pulls up the model page of your part) do not appear to be much different in price - as it is volume that counts, changes in the dimensions tend to affect the price cubed. BTW what is the calculated density of your part (as listed on the "Edit Model" page) ? My rough calculation from bounding box and listed price is around 6%, and if it happens to be below 10% your model will not benefit from the 50% discount applied after the first 20ccm - though it would be a difference of a few dollars in your case).
     
  5. Density is 9.26% lol almost there. Is there any other way i could get these parts https://www.shapeways.com/model/1372376/spor-t-parts.html?li =my-models&materialId=6 made for less? I need one set for a prototype before i send the full design to an R/C aircraft manufacturer. Why i was thinking that a box from around my model was being measured is because i had uploaded a different model that was much larger but cost nearly the same as the one in the link.
     
  6. mkroeker
    mkroeker Well-Known Member
    You could try stuffing the "wing support tip" in there instead of printing it separately (provided there is enough clearance).
    Apart from that, the only way to reduce cost would be to save on material - make the plates thinner or cut holes in them if/where material is not needed for structural strength, especially in the big square plates of the "Spor-T Parts" bundle.
     
  7. The wing suport tips are in there and the plates are a 1/16 or less already so i guess i'll just have to find some other way to get the parts made
     
  8. TrainThingz
    TrainThingz Member
    I'm made to think of a sign my Dad had up in his office at work... He was an aeronautical engineer (Before they started calling it "aerospace")

     
    Last edited: Oct 1, 2013
  9. mkroeker
    mkroeker Well-Known Member
    Depending on where you are, you could perhaps try to find a "makerspace"/"hackerspace"/"fab lab" (community-run shared machine shop) in your neighborhood that offers access to a 3d printer (though it will probably be one of the cheaper and more simple fdm machines, think glue gun on steroids).
     
  10. AmLachDesigns
    AmLachDesigns Well-Known Member
    True in many spheres. However, the ACME Company's grammar left much to be desired...
     
  11. What i'm really confused about now is why my full set of parts is has a volume of about 4cc (checked it with one of the tools on autodesk inventor) which cost about $12 in plastic plus $2.50 for handling, but when i want to buy it, it says that it'll cost me $83.
     
  12. True but 3d printing is not fast nor cheap and an injection mold would do a much better job.
     
  13. TrainThingz
    TrainThingz Member
    Have you priced injection molding????

    You could buy a top end 3d printer for what the molds alone would cost you to have made.
     
  14. AmLachDesigns
    AmLachDesigns Well-Known Member
    What does SW say the volume is? The information is available from the Edit Model view. The implication is that your model is not quite right and that Shapeways is 'fixing' it on upload - closing holes etc. This can have the effect of adding volume.

    If the volume on SW is higher, then check your model for holes in the mesh, non-manifold mesh and inverted normals.

    Edit: Also note that for a model to be hollow in printing terms (as opposed to theoretically) there must be one more more escape holes for the support material. If a hollow is totally enclosed the model will be treated as solid.
     
    Last edited: Oct 3, 2013
  15. mkroeker
    mkroeker Well-Known Member
    Check the scale - maybe something went wrong there, and the parts are either bigger than you need them, or you miscalculated the
    volume in inventor. The two 7x7cm end plates in the "spor-t" set alone would cost around 14$ each if they are 2mm thick (and that is
    ignoring the protruding tube segment), and if you add to that the price of two of the wingtip support things and the motor mount you end
    up not far from what shapeways shows for the kit.
     
  16. It says that the volume is 58.2913cm3. I want my model to be solid which i think i have it designed as.

    "If the volume on SW is higher, then check your model for holes in the mesh, non-manifold mesh and inverted normals. "
    How do i know if i have those? In autodesk inventor it looks fine.

    Once before i had a problem similar to this one in which shapeways said it would cost $300 to print and when i changed it to be availible for sale (i think), it dropped down to $7. that's not working this time though
     
  17. Injection molding is cheaper and faster for the quantity of parts i need. 3d printing 1 set will work for testing the design.
     
  18. My bad, i said the wrong thickness; the plates are 1/32 (.79 mm) thick with .08" (2mm) spikes
     
  19. mkroeker
    mkroeker Well-Known Member
    They do look thicker in the preview - assuming the motor mount part in the kit is the same as your first model, 1 centimeter would be about 1/8th of its length, and the plates appear closer to 1/5th of that than to below 1/10th.
    Is the overall size of your model as reported by shapeways close to your expected value ? You might want to get a copy of the freeware netfabb studio basic from netfabb.com to check size and thickness of your parts - in particular as Inventor appears to have the nasty habit of exporting in centimeters by default.