Already printed model being rejected

Discussion in 'Shapeways Shops' started by Calistotash, Sep 13, 2012.

  1. mkroeker
    mkroeker Well-Known Member
    Did you get confirmation from service on that rejection ? Just in case it was some new shapie who
    rejected a bunch of orders because s/he lacks the experience. (Seems odd to tighten the rules
    for jewelry in the midst of the holiday shopping without advance warning to affected designers)
     
  2. stop4stuff
    stop4stuff Well-Known Member
    The rejections, three so far in the space of 5 days, came from Shapeways Production Partner via Shapeways Customer Service team. Apparently the model has been causing some hassle for some time, but it was only last Friday (7th) that I was first notified. :rolleyes:

    A snippet from the emails that have being going back & forth.

    I've also asked what the recommended wire thickness should be to get the model printed first time every time, but alas, no response as yet and even if a response is forthcoming it will still be too late for those Christmas orders :(

    Paul
    [hr][hr]
     
  3. 7777773
    7777773 Member
    Silver definitely needs to have its rules revised. I've had silver prints rejected lately that print OK in stainless steel - and steel requires *much* thicker walls. Maybe a 4+mm minimum wall thickness for silver would help?
     
  4. BillBedford
    BillBedford Member
    My take on this is that I need to see failed pieces so that I can design around any problems. Having the machine operators repeatedly rebuilding failed pieces seem a waste of time and effort when the solution is likely to take a few minutes work on the original drawing.

    Being able to see your mistakes is the best way of learning how not to design.
     
  5. mkroeker
    mkroeker Well-Known Member
    I fear that production partners may be even more inclined than in-house workers
    to try doing the impossible, and less willing to disclose their misprint ratio.
     
  6. 7777773
    7777773 Member
    Bill is absolutely correct - seeing a failure is extraordinarily helpful to help avoid future failures. I recently had several copies of https://shpws.me/lnj8 delivered to a customer broken. The point of failure got past me, the reviewer, and the print cleaner... but the reason for the failure was obvious to me the moment I saw pics sent to me from the customer.

    Purely by the numbers the model was OK.... however, the customer had ordered the model is WSF-Polished, and the engine pods broke off during polishing. I had designed the supports for the engines with well over the amount needed to print OK, and even to withstand the polishing process... but what I didn't take into account was the twisting forces experienced by polishing media was enough to torque the engines right off. This wasn't a case of having sufficient wall thickness - it was a case of the design in 3D looking perfectly OK on screen, but real-world forces proving otherwise.

    I was (hopefully) able to correct the problem by adding 2 more supports farther off the center axis. This should stop that part from rotating and thus from being twisted off.


    I bring this case up specifically because, if the failure had been reported to me in the standard Shapeways blue-model-red-circle "might break" minimal communications failure email, I'd never have figured out what the issue was.
    I still have not been notified by shapeways of that failure, however. I did update the model a few minutes after the customer contacted me and he sent me a follow-up message later telling me it was being re-printed for him, so we'll see soon if the revised model is the one they are printing, or if they are reprinting the older version.

     
    Last edited: Dec 11, 2012
  7. Bathsheba
    Bathsheba Well-Known Member
    Yes, that's the phenomenon I have in mind. It bites you exactly at the moment when the model starts to get popular and you have a bunch of orders on deadline, because before that moment there wasn't a problem.

    What's needed is to handle this in a way that doesn't blame or shame the people doing the printing. They're on our side...when they push the envelope and succeed with an iffy design, do we write back and say "Hey, awesome print!!"? We do not.

    If we get angry when they try and it doesn't work out, they'll get defensive and start pushing back with more restrictive rules, rejecting models preemptively rather than taking risks near the edge of what the machines can do. I feel like that's not the outcome we're looking for.

     
  8. stop4stuff
    stop4stuff Well-Known Member
    And therein lays the crux of the problem.

    If a design is decided as being iffy but falls within the scope of the material design guidelines and gives the production guys grief then surely (as Bill said before) the simplest solution is for the production guys to share their findings at the earliest opportunity so that everyone can move forward and be happy. With the small mobius pendant, it would take me mere minutes to adjust and upload if I was informed of a suitable wire thickness that would guarantee a successful print first time every time. As it stands the wire for that pendant is 1.30mm (+/- 0.02mm) thick and the Silver guidelines ask for 1mm as a 'free wire', so as anyone would, I thought I had covered the bases by making the wire 30% over the minimum. :cry:

    Paul
    [hr][hr]
     
  9. vertigopolka
    vertigopolka Member
    Well, it has happened again!

    Silver models that were successfully printed in the past have been rejected. It is embarrassing to have models that I have for sale be rejected, especially after I have test printed the models so they wouldn't be rejected. It reflects badly on my shop as well as on Shapeways.

    I have responded (rather emphatically) to customer service. My hope is that they quickly rectify the situation and fulfill the order(s) without having the customer go through hoops to get their prints.

    I know that this is an old story, but every time it happens, it gets me kind of fired up, and I apologize for the rant, and I apologize to the customers who placed orders. If there were problems with printing the initial prints, I was not made aware of them.
     
  10. Bathsheba
    Bathsheba Well-Known Member
    Exactly Paul, what we need from Shapeways is an open feedback channel that is available to the printers whether or not the model is printed.

    Meanwhile I'll say it again: as users we've got to keep our good faith that the printers are doing their best even when things turn out inconvenient. 3D printing, like every other way of making things ever discovered, is a black art. There's no simple set of guidelines that will always predict exactly whether a model is printable. We make mistakes about what the machines can do, and so do the machine operators, and that's life on the cutting edge: we're doing science together.

    If we start blaming them for trying and failing at the edge cases, they'll stop trying, and that would be sad.
     
  11. ZoeBrain
    ZoeBrain Member
    Concur, with emphasis. You covered the issue exactly.
     
  12. mkroeker
    mkroeker Well-Known Member
    That silver casting company is probably going through pre-christmas hell, with every tricky part
    they were proud to have mastered over the year now returning in quantity all at the same time.
     
  13. decapod
    decapod Member
    YET ANOTHER EXAMPLE!

    This has printed before, I have the model.

    The FUD guidelines state:
    How to design thin, unsupported walls
    This pictures shows models made 0.6mm thick sheets (top), and 0.3mm thick sheets (bottom). You can see both models started to warp once the walls get big enough. Based on these tests, we conclude that for models in the 0.3-0.6mm wall thickness range, to keep free standing walls under 30x30mm. For walls of 0.6mm thickness, try to keep your free standing walls under 50x50mm.

    Now the rejection image shows the walls are 0.4 to 0.5mm thick and only 1 or 2mm high!! well within the 30mmx30mm range.

    466777.JPG

    Why the rejection?
     
  14. 7777773
    7777773 Member
    This is the key question. Rejection emails are too often extremely difficult to understand. While a picture is said to be worth a thousand words, a few actual words along with it would be a lot more helpful.
     
  15. mkroeker
    mkroeker Well-Known Member
    This thread mentioned (or introduced ??)
    another rule - "for stability, details have to be as wide as they are tall". (Also in the context of unexpected rejection of a proven
    model). Maybe you got bitten by the same head of that multi-headed monster that dwells in the caverns underneath the printer floor
    at shapeways ?
     
  16. stop4stuff
    stop4stuff Well-Known Member
    Judging by the 0.97 and 2.30 measurements, I'd say the model has been erroneously rejected.
    IMO, the areas indicated are unsuported walls and fall well within the guidelines.

    If you've not already, reply to the rejection email and ask Customer Services.

    Paul
    [hr][hr]

     
  17. decapod
    decapod Member
    Here's the reply from Christel:

    ==================================
    Hi Paul,
    Thank you for writing in.
    Unfortunately we can't see that this model has been printed before, but
    this rejected model also really has got too thin walls and needs to be
    made thicker as well.
    https://www.shapeways.com/materials/frosted-detail-design-gui delines

    Unfortunately I can't promise you that the model in order 179276 is going
    to be printed.
    This is something which is being checked by our Production Facility and
    they will make the call if the model can be printed or not.
    Sorry that I can't help you further with this.
    Kindly,
    Christel
    Happy Holidays!
    Kind Regards,
    Mrs. Christel Hagens
    Customer Service Agent
    www.Shapeways.com
    ===============================
    Link to model: https://www.shapeways.com/model/654487

    Here is the model printed a few weeks ago, about 12cm long and 2cm wide
    WP_000426.jpg
     
    Last edited: Dec 14, 2012
  18. stonysmith
    stonysmith Well-Known Member Moderator
    After the print you show in the picture, did you upload an updated copy of the file?
     
    Last edited: Dec 14, 2012
  19. decapod
    decapod Member
    After the print I discovered a detached shell which was fixed and updated on the same model id using the same file name.

    I replied to the last email as I wasn't really happy about that and Christel has since replied that they're looking into it now.

    If you believe you are right then I think it pays to persist as the first reply from customer service will try and put you off.
     
  20. Youknowwho4eva
    Youknowwho4eva Well-Known Member
    As I'm sure Stoney was getting to, if you update the file, it resets the printed before. Doesn't matter if it's the same file name. So that's why Christel can't see that it was printed before.