How to produce many small identical parts - high cost?

Discussion in 'General Discussion' started by nickdk, May 22, 2012.

  1. nickdk
    nickdk New Member
    hello everyone :)

    I'm making a modular system that will consist of a lot of small identical parts (like 500) connected by some connector parts. When I upload one of these small parts it gets extremely expensive for each copy. What could i do to include many parts in 1 print job - the price i get doesn't reflect the used cm3 at all, i think it's due to startup cost being added to every part? would i have to connect the parts by a thin line to make the 3d printer create them all at once and then manually separate them later?
     
  2. nickdk
    nickdk New Member
    I just realized that I can have multiple separate non touching copies inside a single upload job file - DOH

    I guess this is the way to handle small identical parts?
    I always thought that i had to create 1 job for every 1 part :S :eek:
     
  3. TurtlesAreCool
    TurtlesAreCool New Member
    You can do that, but you probably shouldn't. Lots of small items would increase the effort required by Shapeways to gather all of your objects, making the handling cost much higher than it should be.

    The likely suggestion is to link your models together using sprues of some sort, like the pieces in a store-bought plastic model airplane. Alternatively (I don't know this for sure), a mesh cage to hold all the objects might be doable as well. I'm hoping that someone with more experience with such things will chime in here. I just wanted to encourage printing, but discourage behaviors that would harm our beloved Shapeways.

    Oh, and welcome to the community. :D If you give an idea of the scale and quantity of your parts, that might help folks guide you towards a good solution.
     
  4. stonysmith
    stonysmith Well-Known Member Moderator
    The question is.. HOW small? If the items are smaller than 1cm3 cubes, then they are extremely labor intensive to remove from the printer.

    Shapeways current rules allow a number of discrete shells. If designers start abusing that with large numbers of independent parts, then they will be forced to either reject the models, or go UP in the 'setup fee', which none of us would want.

    Keep in mind that models must be picked up by hand (fingers) and placed into the baggies... If they have to repeat that 500 times per file, it's going to drive up their costs.

    Use the sprues or the bounding box concept and you should be fine..
    Here's one example: http://shpws.me/3XYE
    The items here are about 2mm in diameter, and 3mm tall.. just imagine trying to retrieve all 200 of those out of the printer if they were separate objects.
     
  5. nickdk
    nickdk New Member
    the parts are 'beams' 0.8x1.6x25mm - i think the parts will be quite fragile so i'm not too happy intersecting them.

     
  6. stop4stuff
    stop4stuff Well-Known Member
    You could put the beams loose in a box - 500 of the beams you describe comes in at 16cc, ($23.90) add the volume of the box and the total price is much less than 500 individual models ($1.54 each)



     
  7. Tbmod
    Tbmod New Member
    Problem with that is the box needs to be an open mesh work one so Shapeways can clean the print.

    Something 0.8 x 1.6mm is going to fall out of any mesh big enough to let them clean the contents.

    Tom
     
  8. stop4stuff
    stop4stuff Well-Known Member
    Think outside the box and a solution becomes very clear :rolleyes: -
    The box does not need to be a mesh structure.
    The box can have closed ends and partial closed sides that overlap the ends of the bars (allowing for clearance spacing)
    The box can have a central pillar in the open sides.

    Just one kind of box that could work ;)

     
  9. SirThankzALot
    SirThankzALot New Member
    If too many tiny pieces are a problem for Shapeways, you could create a scaffolding or somehting that can be snapped or sanded off, enough for the piece to successfully print, then go to a hobby store and make a mold and cast your own copies.
     
  10. nickdk
    nickdk New Member

    Could someone show a drawing of such a box? I'm a bit confused about the box method - I don't want to complicate things too much :S
     
  11. stop4stuff
    stop4stuff Well-Known Member
    For sure, give me a day and as long as no paid work comes in, I'll have a box model that can work by this time tomorrow - can you PM me with the base model you need multiples of?

    Paul

     
  12. nickdk
    nickdk New Member
    Paul that's very nice of you, the base part is not in place yet, I was just asking for a quick sketch or so to show the box idea :) I can model it myself.
     
  13. stop4stuff
    stop4stuff Well-Known Member
    no worries :)

    Sketching with imagination here (modelling would take less time than pen & paper)
    grab a shoe box, fill it with twigs just a little shorter than the box length - fill the box but allow clearance spacing between the twigs.

    Now grab a sharp knife and cut out two windows that are about 1/3 the length of the sides and top of the box, space the windows evenly so that there is an upright between the pair of windows on each side - do not cut windows on the ends.

    Does that do it?
     
  14. stonysmith
    stonysmith Well-Known Member Moderator
    Here's one suggestion.

    Box.jpg

    In this design, the "cap" on each end needs to be enough to keep the items from falling out. Depending upon how many items you are trying to print at once, you may need internal cross-braces to keep the items "standing up".
     
  15. nickdk
    nickdk New Member
    thank you very much, i understand the concept now! :)