Some time a model rejected for no real reason...

Discussion in 'Suggestions & Feedback' started by Vidalcris, Sep 12, 2013.

  1. Vidalcris
    Vidalcris New Member
    Thats the biggest problem on Shapeways in my opinion.
    Your services are not regular for a peny :rolleyes: :twisted:

    I hope u can make something to explain them that they can't say me that my models are rejected when i already sold this particular model a lot of time !!!
    The more funny in this is that i just have to reupload the same model again and by the way 90% of the time you print it without any problem ...

    I already know your answer but i dont agree, this is a non-sense... You print a model , then you reject it, then without any modification you print it again and again and again ... then you reject it !! then without modification you print it again and again !!

    Each time you reject a model the mistake is the same. By the way if you mesure an edge on a model you can always find a smaller value if you take your mesure more on the top of the edge ! so thats easy to reject any model ...

    I think that a system to confirm models and make them directly printable without verification would be awesome !
  2. bartv
    bartv New Member
    Hi Vidalcris,

    if you have printed your model successfully several times before, then we should accept it - just contact about it. In some cases though, we find that model has a high failure rate and in such cases we may still decide to stop producing it..

  3. Vidalcris
    Vidalcris New Member
    Ok but i dont think that a round spike can be a failure ... So how can this happen ?

    My suggestion stay the same :
    I think that a system to confirm models and make them directly printable without verification would be awesome !

    This is a smoothed new models that you asked me to make in order to print it again :

    And the actual printed model before, without any smoothing on the model :
    Last edited: Sep 12, 2013
  4. bartv
    bartv New Member
    Sorry, I don't have the right information to discuss this particular case here. Please talk to customer service - then can help!

  5. Vidalcris
    Vidalcris New Member
    I can speak hours with them ... the problem will be the same another day !
    I cant loose hours everyday to speak about non-sense ...

    This is my suggestion one more time :
    I think that a system to confirm models and make them directly printable without verification would be awesome !
  6. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    Of course it'd be awesome to have the verification be completely automated. But there are times when an item passes every guideline and still has printing issues. It appears to me that your first model should have been rejected. Being smooth or not. Once the thickness goes below 2mm, it becomes a detail. Minimum detail for sandstone is .4mm. A detail shouldn't be taller than it's width, so once under 2mm your angle shouldn't be less than 45 degrees. The hair on the printed model, and on the rejected model appear to be below 45 degrees. In my opinion, an automated system would have failed both.
  7. Vidalcris
    Vidalcris New Member
    I'm not speaking about automated system but just if you already printed something correctly add a value to the models to know that u dont have to verify it again :)

    About the 45° this is the first time someone understand what i'm speaking about and i have to say you a big thanks !! :p
    Changing all angle on this model to 45° is just ... a lot of work and i dont have an automated system to verify anything ...

    An old suggestion that i emailed was to use a system like competitive service. We can see directly if the model got too thin parts and then make modification accordingly.
  8. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    As Bart mentioned, we do have a previously printed flag. So once checked, it's not manually checked if printed in the same material again. But, as Bart also mentioned, there are occasions where something that gets printed that shouldn't have, or even that should be printable but for some reason has a high failure rate in printing, finishing, and/or shipping.

    I can understand your frustration with getting a model to be 45 degrees or greater, especially an organic sculpture. But this is to help prevent damage, especially from handling and shipping. In Sandstones green stage, it is very fragile. After applying the super glue like coating, it's stronger, but it still has to survive UPS.

    We are aware of competitive services and the tools they provide. That's not my department so I don't know much more than that.
  9. Vidalcris
    Vidalcris New Member
    Bart was not talking about the flag , But anyway ;)
    So that mean you printed it and then it was broken ? ^^
    But where ?
    This is not a problem if a spike is round as i said.
    And i dont understand which other parts can be a problem on this particular model ...

    Everyone can understand that a spike is round because of shipping or anything, this is not even a reason to cancel an order from a customer because they are aware of this sort of problems...

    Under 45° or not there is always a very small amount of material at the top of the edge.
    And i know because i already received more than 50 3D printed models what a Zcorp 3D printer can do ...
  10. Vidalcris
    Vidalcris New Member
    And i have to add :

    You said "Being smooth or not." but i think that you will have no problem to understand that the edge is a lot thinner on a normal 90° edge without smoothing than on my last smoothed model ... By the way when i smooth an edge there is no more edge ;) And when you say 45° you are speaking about an edge.

    So please i like shapeways a lot and i'm not using "Non-Sense" for nothing ... I'm mechanical technician too and mechanical designer so maybe my english is far from perfect but i know exactly what i am talking about !

    So now explain me why u will accept a non smoothed 45° Edge and reject a smoothed 30° one where the final product will be a lot more solid than the 45° non smoothed ?

  11. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    I can understand your confusion. The angle I'm referring to is the one shown in this image. I just drew lines on your image to get a rough angle. This angle here must be 45 degrees or greater when the thickness is under 2mm. As you can see the rough estimate of the angle is 36 degrees.
  12. Vidalcris
    Vidalcris New Member
    I'm explaining to you that i'm mechanical designer and you come back eplaining me what is an angle ???
    I'm sorry but there is absolutely no confusion for me ... are you kidding me ?

    You say that u can print the Green part but not my smoothed spike ?? this is a joke, just take a look at my picture ...
    Last edited: Sep 12, 2013
  13. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    Ok, that was confusion on my part. I thought that you were referring to your printed piece having the hair be more square, where your new model is rounded all over. Where you are directly referring to just the ends of the hair coming to a round rather than a point.

    Also in my previous post I misspoke. The angle as measured should be 90 degrees (45 degrees on each side) when the walls are under 2mm.

    By the rules for details, the tip would have to look like the drawn triangle.

  14. Vidalcris
    Vidalcris New Member
    I can make one more time the same picture with the spike of the 90° this is exactly the same story i'm sorry... i mean there is less material on the 90° spike than on the smoothed one.

    If what you say on your last message is the new rule i have to say that competitive service is way better than your service to make spikes ... and i'm really sad to say that :'(
  15. stonysmith
    stonysmith Well-Known Member Moderator
    There's quite a long thread here &prevloaded=1&&start=0 about rejections. If you skip over some of the side discussions, you can get a better picture of the process that kicks in when a model fails to print.

    Regardless of how carefully (we) design models, there are some that are just plain problematic. Shapeways goes to quite long lengths (possibly more than they should) to achieve successful prints. A part of their process is to track the failure rate for how many times a particular model has issues. It's a better determination than "okay it printed once.. allow it always" .. but yes, it can be frustrating.

    As I've expressed elsewhere, there is a choice: Shapeways can jack up the design rules such that NOTHING can be less 5mm thick and thereby ensure that there is 100% repeatablity, (they could print solid cubes/spheres with no detail all day long) or they can continue to let us push the limits of this technology - we must be patient with the process if desire to see what the limits can be.

    NOTE: I say this from my own frustrations with rejections, not to denigrate the particular issue @Vidalcris is having. Trust me.. I've pushed the design rules as hard as i possibly can, and I'm a bit surprised that Shapeways lets me keep doing so, but glad they still put up with me. <GRIN>
  16. Vidalcris
    Vidalcris New Member
    Thanks a lot for your message Stonysmith :)

    The problem for me is that i'm speaking about a rejection for a spike, not for a small part that can make the model breaking in two parts during the process ...

    The real choice from Shapeways is to know if they want to make money ;) This is why the rules are not so hard.
    Btw if the minimum thickness allowed was 5mm without anything under 90° then no one will use Shapeways...
  17. stannum
    stannum Well-Known Member
    An isosceles triangle of base 2mm and height 2mm (the twin sides are thus sqrt(5) or ~2.2mm) has a top angle of 2*arctan(0.5), so ~53 degrees.

      / | \~2.2
     /  |2 \
  18. Vidalcris
    Vidalcris New Member
    Thanks a lot Stannum ;)

    Now i know that 53° is the minimum angle to use on a spike :p

    Can you code a plugin for C4D to remesh automatically with this parameter ? XD

  19. stonysmith
    stonysmith Well-Known Member Moderator
    Again, not to distract from the main topic, however.. the issue at times is not so much about YOUR model breaking, but what happens with that small spike if it were to come loose within the print batch?

    It took me a long time to comprehend this, but that small spike, were it to break off, could go "surfing" and end up landing next to somebody else's model. It can also then cause the "print head" of the machine to "bump" as it passes over it. That means that there could then be an irregularity across the entire batch of models, not just yours. Shapeways describes this as simply "risk of destroying a batch", and it took me a very long time to comprehend that MY model could negatively affect models purchased by other buyers.

    If all the models were printed by themselves, one at a time, it wouldn't be an issue. But, we see lower prices at Shapeways because they can utilize the entire volume of the printer at once, thereby saving on the costs to operate the machine.
  20. Vidalcris
    Vidalcris New Member
    Ok now i really understand where is the problem :D
    Thanks a lot again StonySmith for your patience and your nice message !