Size misprint 43mm => 41.6mm

Discussion in 'Technologies and Hardware' started by pongstak1, Dec 24, 2011.

  1. pongstak1
    pongstak1 New Member
    I've been happily 3D printing for months (thank you, Shapeways). All my printed parts matched the uploaded STL in dimensions. However, I just got a part that doesn't match the uploaded STL. It is too small (41.6mm vs 43mm). This is sad for me because my 36mm printed circuit board doesn't fit in the shrunken 35mm space of the printed 3D case. My first thought was that I might have uploaded improper STL (e.g., mistyped scaling as 24.5 vs. 25.4). However, I downloaded the STL to verify dimensions: http://www.shapeways.com/model/edit/367832/
    NetFabb reports the length as 43mm, but the 3D part is 41.6mm. This leaves me with a useless part and some concern about what happened. In particular, I would appreciate advice on how to prevent this in the future.

    Help,
    Karl
     
  2. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    Karl, what material did you use? I know stainless has a high tolerance. If you ordered in any of the plastic materials or silver, I'd email service@shapeways.com with pictures, order number, and a description of what is wrong as their tolerences are tighter and shouldn't have that big of a difference.
     
  3. pongstak1
    pongstak1 New Member
    Thank you, 4eva. I will email support directly with particulars.

    The material used was WSF plastic, which normally has sub mm tolerances. In this particular print the scale on all three dimensions was off with a cumulative error of 1.4 mm. Another piece in the same order came out fine. Very strange.

    I will report back to forum with more info as it becomes available.
     
  4. Texel2001
    Texel2001 New Member
    My batch is allso way off. $130 down the drain!!!
    [​IMG]
     
  5. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    Texel, your image isn't working
     
  6. Texel2001
    Texel2001 New Member
    better?

    Im in the process of checking the measurements.

    First impression is that x and y are about 5% to small.

    Will post more later. PC294586.jpg



     
  7. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
  8. Texel2001
    Texel2001 New Member
    Sure i will. Ill even drive up to them as i live, relativly, close to Eindhoven.
     
  9. pongstak1
    pongstak1 New Member
    Well, this is embarrassing. I can't find the part to take the pictures that support@shapeways.com requires. I fully blame the new kitten, who is really into Shapeways soccer.

    theaponstak.JPG

    Anyhow, yes. As 4eva mentioned, the process is definitely to take pictures of the misprint alongside a ruler for dimension verification. Apparently WSF misprints do happen. That surprised me, since the previous 11 parts ordered were absolutely perfect and insanely accurate.

    I did make the suggestion that Shapeways should consider giving customers an option to pay a little extra for "high-accuracy WSF." I would pay the premium for the up-front guarantee of accuracy. That proposed option makes more sense to me than playing accuracy roulette.

    Karl

     
    Last edited: Dec 29, 2011
  10. pongstak1
    pongstak1 New Member
    Oh. Here's another thought...

    If you're ordering interlocking parts with high tolerances that do not require "real-world accuracy" but do require "self-consistent accuracy" (e.g., a model to assemble), it might make sense to put all the parts together in the same upload so that they would still fit together independent of shrinkage (presumably because they would all be part of the same print).

    In my case, I did order two parts in the same order, but one was WSF and the other was ISF. The indigo part was perfectly accurate, but the white part wasn't. The color-change setup put the ISF part in a separate print than the WSF part, which meant that the WSF shrinkage resulted in two parts that should, but don't fit together.

    Karl
     
  11. Texel2001
    Texel2001 New Member
    To be sure Shapeways could deliver relatively accurate parts i designed a test-object to test for accuracy.

    I ordered in BSF and RSF both where spot on.

    So i thought i could order some large objects for my project.

    5% off is way to much!

    I contacted service and waiting for a reply.


    29-12-2011 18-54-52.jpg