Making Sprue For Small Parts

Discussion in 'Miniatures and Scale Models' started by Freakazoitt, Jun 15, 2019.

  1. Freakazoitt
    Freakazoitt Well-Known Member
    Shapeways refuse to print some of my models, because they are connected with 1x1mm squares to 2x2mm sprue. But i can't make 2x2mm connection because it's twice bigger than model parts. Other way I can't remove sprue at all, because pricing force me to add sprue on every model. If I follow printing rules, customer will recieve parts that he can't remove from sprue without crushing it with hammer!
     
    ptlmyoung likes this.
  2. lawrencekramer2014
    lawrencekramer2014 Well-Known Member
    What material is involved? I'm using connectors that are at least 0.2 mm larger than recommended minimum thickness in all directions for the materials I am ordering, and a few mm long between objects (eg .82 mm x .84 mm x 4.0 mm in silver). Basically it's just a fancy grill then, where every part of it meets minimum thickness and has a decent structural strength on a flat plane. Hope that helps. Also see the DIY description at the top of any page on my website for how the customer is asked to cut things apart.
     
  3. Freakazoitt
    Freakazoitt Well-Known Member
    Smooth/Smoothest Detail material. Recommended sprue is 2x2mm. But model parts are smaller, so it would be impossible to remove parts from sprue othr than breaking all
     
    ptlmyoung likes this.
  4. lawrencekramer2014
    lawrencekramer2014 Well-Known Member
    If the material is "Fine Detail Plastic"
    Also known as Frosted Detail Plastic, Resin-based Acrylic Plastic, Photopolymer
    then the specs are:

    WALL THICKNESS
    [​IMG]
    Min Supported Wall Thickness
    0.3 mm
    [​IMG]
    Min Unsupported Wall Thickness
    0.6 mm
    So I would recommend sprues at least 0.7 mm by 0.7 mm by whatever length is required.
    I recommend square, not cylinder, more strength when making.
    I know finding the material specs is harder than it used to be.
    this one was at:
    https://www.shapeways.com/materials/fine-detail-plastic

    I would ignore the advice that is way in excess of the stated design guidelines.
     
  5. Freakazoitt
    Freakazoitt Well-Known Member
    Shapeways specialists reject printing until I make 2x2mm sprue
     
  6. lawrencekramer2014
    lawrencekramer2014 Well-Known Member
    Can you share the model involved? and confirm the exact shapeways official name for the material?
    If the model meets the minimum unsupported wall thickness everywhere in the model and has good structural strength it should not be rejected. Is there any red at all on the model when you do the wall thickness analysis on it?
    By the way, it may be counter-productive to call any part of the model a sprue, it's all just a model, no matter what it is used for.
     
  7. southernnscale
    southernnscale Well-Known Member
    my smallest has been 0.052mm and 0.72mm. in this photo!
    IMG_4943.JPG
     
  8. ptlmyoung
    ptlmyoung Member
    yes they have NO idea what they are doing just because some guy who hates his job and is very ruff with the brake down and your parts (small) gets tangled into other big parts and gets damaged so they blame you for thin walls and when you complain to them they give you a bunch of stuff about thin walls i.e. you can have two wall separate by .005mm and pass the thin wall shit but let .0005 mm touch at the corners and they loose their minds about the thin wall shiz i have one now i had it print fine with print anyway then later they say it has thin walls and block the sale and the spot was at the spur and i had to use a knife on mine in the same spot they say it had a thin wall. WHICH IT WAS INTENDED TO!!! so you can remove it. I been doing this for years and it start at min .7mm the went to .9mm and 1mm if they keep there shiz up someone will come along and take there sellers and then costumers and at the prices they charge is a crime for them to complain just print the items!!
     
  9. ptlmyoung
    ptlmyoung Member
    if it is not intended to be part of the final product and only to hold the parts together it is called SPRUE
     
  10. lawrencekramer2014
    lawrencekramer2014 Well-Known Member
    Technically, you are quite correct. Problem is, shapeways was rejecting things that were referred to as sprues in models, but would print them if you did not say the model contained sprues. Example below:[​IMG]