jump line in large models.

Discussion in 'Suggestions & Feedback' started by jcbear, Jun 4, 2014.

  1. jcbear
    jcbear Member

    On Friday 30 May 14 I took delivery of a print – standing human figure, actually a devil figure – approx 65 cm tall, in white sf.

    It has a 1 mm sideways jump around the middle. I e-mailed customer service, received no reply, and eventually, poking round the website, found that the design guidelines had been amended with the following paragraph added:

    For models larger than 33cm: Our Strong & Flexible 3D printers operate with two lasers at the same time. If a product in the printer is located in the overlap plane where the two lasers meet, miniscule calibration differences between the lasers may create a visible line on the surface of the product. We aim to arrange products in the printer away from the overlap plane. However, products larger than 33cm long in any direction may be too large to fit in one laser's area, so you may see a visible line along the overlap plane on your product.

    I don't know when this change was made, but it must be relatively recent because I have not seen it before today [2 Jun 14] though I often consult the design rules. It may even be a reactive change, given queries from multiple customers. I assume there is no point in arguing about my print, given that the 'fine print' has changed, and I expect I can clean up the print.

    But I am distinctly annoyed. Particularly given that the price of my 65 cm tall print was well into four figures. I very much doubt that I am alone in this situation.

    Given the general precision of 3d printing, I do not understand why this problem occurs at all. Nor should anyone else. Surely the two lasers in the printing machine can be brought into closer alignment, or the machine improved/retrofitted so that this adjustment is achievable.

    And a 1 mm misalignment at this scale is not, remotely, minuscule .
     
  2. HOLDEN8702
    HOLDEN8702 Well-Known Member
    What a pity!

    How about some photos?

    regards

    Luis
     
  3. MitchellJetten
    MitchellJetten Shapeways Employee CS Team
    I see that Joost replied your email 5 days ago, requesting a picture so he can raise a complaint and have it investigated.
    However I do not see any reply on his request from your side.

    As for the text on the materials page, this has not been added recently, it's actually on the website for quite some time.
     
  4. jcbear
    jcbear Member
    Thanks for this.

    I did not get an e-mail from Joost, I'm afraid, assuming it went to jcbear@nf.sympatico.ca where I have been receiving messages from Shapeways including the occasional one from support people.

    All I can say is, the last time I looked at the wsf material, the pgph about big models and the 2-laser issue was not there. I can't swear when that was, but not months ago or something like that.

    I have attached images to this message [I think]. It looks to me like its the two-laser overlap effect.

    Regards,

    J C Bear

    View attachment 61100
    P1010959.jpg
    P1010960.jpg
    P1010961.jpg
     
  5. HOLDEN8702
    HOLDEN8702 Well-Known Member
    It's a shame.

    I have no words.
     
  6. Bobbiethejean
    Bobbiethejean Well-Known Member
    Ayeeee.... Yikes. Could you sand that down perhaps? ^__^;
     
  7. mkroeker
    mkroeker Well-Known Member
    That paragraph does not look familiar ? Pity that the internet archive does not do more frequent snapshots (and pity that we as customers would have to resort to such means to be made aware of changes on the materials pages), but at least this paragraph was added later than February 17.
    I guess you have some blanket disclaimer in your t&c that you reserve the right to change all your rules without notice, but such things do not actually instill confidence.
     
  8. AmLachDesigns
    AmLachDesigns Well-Known Member
    I guess we could see when it changed from the easily accessible, comprehensive change log or a post on the forum from SW - now where might those be...

    All sarcasm aside, I have not seen this paragraph before, either. It would be instructive to know whenever the Materials pages change as they are in effect SW's contract with the designers. Any changes should, imo, be very publicly made.
     
  9. jcbear
    jcbear Member
    Thanks for this.

    I expect that I can mechanically deal with the overlap line, one way or another – sanding, small files or other tools. I remain surprised that this should be necessary, however.

    Aside from my own surprise, to put it mildly, at this issue and how it it has developed, and since this comment has been moved to Suggestions, I formalize my suggestion as follows:

    If a bounding box is 650 mm long, it is hardly surprising that some people will use that fact to make models longer than 330 mm. A 650 mm long print is likely to be rather expensive, compared to smaller ones. Why should someone be expected to do extra finishing work on such a large, costly print as contrasted with something smaller? And – while emphasizing that I have no familiarity with the actual details of a printer's workings – I am surprised that this issue arises at all. It certainly seems as if this is something that can be handled with mechanical and/or software adjustments to the machine. So, I suggest that this issue can and should be fixed.
     
  10. HOLDEN8702
    HOLDEN8702 Well-Known Member
    I'm sure that a customer (not designer) that makes a complaint for that issue, automatically gets a refund.

    I have to repeat: It's a shame!

    Somebody in purgatory loves the designers,... in an odd matter!
     
  11. Andrewsimonthomas
    Andrewsimonthomas Well-Known Member
    The way that these larger machines work is they use two lasers that need to have a slight overlap in order to make sure that they fuse properly. If there were just one laser for 650mm you'd see a certain amount of distortion in the print, so a single line in the model is a trade-off for an overall more accurate print.


     
    Last edited: Jun 11, 2014
  12. HOLDEN8702
    HOLDEN8702 Well-Known Member
    This means that a larger model is cheaper because it has this quality issues... No, wait! in larger models is applied the funny rule

    "Bounding box pricing on big low density products

    Large, extremely low density models printed in White Strong & Flexible are priced based on bounding box volume rather than material volume. For models with a bounding box over 10,000cm3 and a density less than or equal to 2.6%, the price is $.0385 per bounding box cm3 plus a base price of $1.50. See our blog post to learn more. "

    (you can watch it in https://www.shapeways.com/materials/strong-and-flexible-plas tic ).

    and this made the model too expensive and beyond our sad economy, as I discovered last summer with a model my own:

    https://www.shapeways.com/model/1247074/1-144-brandenburg-ga te-ruins.html?modelId=1247074&materialId=6

    Very nice. Too much over the real price, too much under a minimum of quality.
     
    Last edited: Jun 6, 2014
  13. mkroeker
    mkroeker Well-Known Member
    Just out of curiosity (and sorry for increasing thread drift), what is the actual density of that Brandenburg gate model ? If I remember correctly, that density rule was imposed as a reaction to a huge wireframe sculpture, and while it is plausible that your hollow model is below 10% density (thus missing the
    threshold for the volume discount), I would not expect it to be below the 2.6 limit that completely changes the pricing. (And if density is close to either of
    the limits, it might be cost-effective to make some wall a little thicker, introduce a crossbar or even a free-floating small box).
     
  14. HOLDEN8702
    HOLDEN8702 Well-Known Member
    Hi, Mkro.

    It's 1.13 % desitity.
     
  15. 7943_deleted
    7943_deleted Member

    Hey AmLach,

    Here is the easily accessible, comprehensive change log that is updated weekly:
    Website Change Log

    Also, any major changes are always announced in the Official Announcements thread - that first one on the very tippy top of the forums ;-)

    Cheers,
    Natalia
     
  16. AmLachDesigns
    AmLachDesigns Well-Known Member
    Hi Natalia,

    fair point.

    However, I wonder how many people do not read locked threads because they assume they have already read it? Because the padlock never changes colour it it's impossible to tell, and after having been caught out several times before, now I don't bother.

    Secondly, on the log where does it tell us when specific things have changed? In this specific instance, when was the text about the twin lasers added and where can we see this on the log? Imo the materials pages are not things that should be changed without highlighting the fact more than is the current case to designers. Otherwise we will have to go back to these pages every time to check that nothing has changed.
     
  17. mkroeker
    mkroeker Well-Known Member
    My point, and I guess his as well, was that such changes to the Materials pages are not currently reflected in your change log (nor anywhere else, not even by a "last changed" date on the Materials pages), so the only thing we can be sure of is that the text was added after February 17 (the day that archive.org took the latest snapshot of your site).
     
  18. 7943_deleted
    7943_deleted Member
    Ahh, I see what you mean now.

    We usually announce separately any Design Guideline changes (like changing the rules for FUD)

    The twin lasers thing has been part of our process since we got the Big Bertha machines (the big EOS printers that have the two lasers). THis is detailed on our Materials Page for Plastic under the heading:

    "Max Bounding Box"

    Theres a way to see how that page used to look before the visual refresh, to show you that it has always been on our website like Mitchell remembers -- hmm its an app called WayBackMAchine or something I think?? My memory is failing me, let me google it! ;-)

    Natalia
     
    Last edited: Jun 11, 2014
  19. stannum
    stannum Well-Known Member
    Déjà vu. Yep, bug filled under suggestions (got moved IIRC, but it's a bug, just look at bottom of index pages, as useful as semaphores with two pink lights), with diagnosis and workaround (fix is changing a file, which is also provided for free as part of workaround). A previous bug report is 2 years old and counting.

    Were old big prints done with other machines? Because 650 × 350 × 550 mm was listed as maximum bound box for WSF for longer, without mention of the line issue.
     
  20. MitchellJetten
    MitchellJetten Shapeways Employee CS Team
    Same machine!
    Way back we did not mention this on our website which caused even more frustration (people expecting us to reprint the model without any overlap, which is impossible)
    I think this was added when we changed the layout of the page.

    As soon as your model is larger than 35 cm we will have to print it horizontal, meaning it will have an overlap.
    We always try to minimize the overlap, but it will be visible, always.
    In case of the model in this topic, it's bigger than it should/can be and thus we should help him out at customer service.