Black High Definition Acrylate For Sale To Shoppers / Updated Guidelines

Discussion in 'Official Announcements' started by Andrewsimonthomas, Sep 20, 2016.

  1. railNscale
    railNscale Well-Known Member
    Hello Shapeways-Team,

    We've addressed questions to you about Black HDA.

    Since we beleive it is crucial that products need to be geometrical accurate, we've raised the following questions:

    Below you find our findings, based on the 3 prints in B-HDA. Which of these findings are confirmed?

    1. Potentially B-HDA has a very smooth surface quality that matches the surface quality of injection moulded parts. However the other print shows almost as much sharp edges as FUD. Appearently the printing proces shows a lot of deviations. So, it should be a plus. But not always! The inconsistiancy in print quality is a big concern;

    Question 1: What surface quality will SW guarantee?
    1A. Entirely smooth without ripples
    1B. Anything between the extremes we've seen can happen and are part of the proces

    2. We mentioned that B-HDA does not require elaborate cleaning. The second print however was sticky. Not sure whether this model can be painted properly;

    Question 2: I assume the sticky surface was a result of improper UV curing. Will SW guarantee sticky free surfaces?
    2A. Yes, all B-HDA prints will be free from sticky surfaces
    2B. Anything between the extremes we've seen

    3. For painting purposes a brighter colour (white, bright gray) would be welcomed;

    Question 3: Will other colours become available?
    3A. Yes
    3B. No
    3C. Maybe in future

    4. The dimensional quality of FUD is better. All B-HDA parts were warped, in different ways. Warpages seem to be a B-HDA feature.

    Question 4: Will geometries that are in agree with the design guidelines be free of warpages? *
    4A. Yes
    4B. No, this is part of the printing proces. So basically designs that made out of multiple parts that should have a tigtht fit are not suitable designs.

    5. B-HDA does require the removal of support material with knives. This removal is not only labour (cost) but adds inconsistency and damaging of the B-HDA parts.

    Question 5: What does SW consider acceptable manual damages?
    5A. If a customer complains, he will allways be refunded
    5B. Cutting damages are part of the proces. These imperfections cannot be avoided.

    All 'A' options would mean that B-HDA will make it to our shop too.

    Please answer these questions.

    Regards,
    Maurice & Joris
    RAILNSCALE

    * Note: SW states in the material properties chart of Black High Definition Acrylics that the geometrical tolerances are: +/- 0.1 - 0.2 mm per 100 mm. This figure is the exact same as the official tolerances of FUD/FXD. Strange. Our previous prints in B-HDA showed that B-HDA was no way near FUD/FXD. Warping and bended edges were seen on various spots. So the accuracy of B-HDA in these prints is way worse than with FUD/FXD. Based on your claim all our current designs should be printable without any geometrical defects...
     
  2. Andrewsimonthomas
    Andrewsimonthomas Well-Known Member
    Hey @railNscale we've seen your question, we'll get you some answers on these soon :)
     
  3. bgeorgakas
    bgeorgakas Well-Known Member
    @railNscale - I put together some answers to your questions. I hope this is helpful!

    Question 1: What surface quality will SW guarantee?

    The ripples that you experienced in your print were the result of a defect and are not inherent in the process. SW will guarantee against surface quality issues such as these. The quality standard has evolved since launch as we experienced new types of unexpected defects. Surface issues that you can expect will include marks where support structures were removed. This is inherent in the process. SW production planners do their best to orient parts in order to minimize supports.

    Question 2: I assume the sticky surface was a result of improper UV curing. Will SW guarantee sticky free surfaces?

    Surfaces should not be sticky - and yes - this is a result of not being fully cured. The one caveat to that is that in order to fully cure, the surfaces must be able to be exposed to UV light. That means that internal cavities and hidden surfaces may not get direct UV exposure. If areas did not get fully cured, this should be caught during our quality checking.

    3. For painting purposes a brighter colour (white, bright gray) would be welcomed;

    Question 3: Will other colours become available?

    This is certainly a possibility and something we have been thinking about. This will largely be driven by feedback we get from the community so we would love to hear what you all think.

    4. The dimensional quality of FUD is better. All B-HDA parts were warped, in different ways. Warpages seem to be a B-HDA feature.

    Question 4: Will geometries that are in agree with the design guidelines be free of warpage?

    Warpage is a very design dependent and unfortunately, we cannot guarantee that if it meets the minimum guidelines, it will not warp. However, we have updated the guidelines to better instruct how to design to avoid warpage. We found that longer walls and wires warp much easier than shorter ones (which is why we added some thickness recommendations depending on how long your feature is). There are other considerations as well though including the how the wire/wall is supported so it's hard to make guidelines that will cover everything accurately. We do a quality check to ensure your model is not warped before shipping. Sometimes, we have found though that the material can relax/relieve stress and thereby warp during the shipping process. Please reach out to customer service if you have see this in your models.

    Question 5: What does SW consider acceptable manual damages?

    This is handled on a case by case basis. Usually, customer service will ask to see a picture of the damage so that we can determine what are just support marks and what are divots, scratches, broken pieces etc that are not acceptable.
     
  4. woody64
    woody64 Well-Known Member
    The customer also claimed: the material feels sticky and on the surface there were a lot of small crumbs.

    But more problematic is that it seems that the part was a little bit smaller then it should be. In my case the model hasn't fit on the head of the Minifig without removing material with a knife?

    Can somebody take a look on it and advice how to proceed, shall I contact service?
     
  5. Andrewsimonthomas
    Andrewsimonthomas Well-Known Member
    @woody64 you should have them contact service. seems like some amount of shrinkage or might have warped... unsure until we investigate.
     
  6. czhunter
    czhunter Well-Known Member
    Sure - light grey is imho the best way to go.
    Its not a coincidence, that vast majority of injection moulded plastic kits and surface primers and putties are light grey - something between RAL 7035 and RAL 7040.
     
  7. railNscale
    railNscale Well-Known Member
    Thanks for the answers.

    The 'warpage' bit remains the biggest concern.
    Based on the answer and our results it seems not possible to claim that B-HDA reaches a accuracy of: +/- 0.1 - 0.2 mm per 100 mm. This figure is the exact same as the official tolerances of FUD/FXD and would be very hard to see! This can't be true. Even if you take all design guidelines in mind.
    Example 1:
    [​IMG]
    The Mercedes Truck we ordered in HDA has a cargo bed. Max length: 18 mm. The side boards of the cargo bed are 2 mm in height. The wall thickness varies, but the larger part is 0.8 mm (some parts are sligtly less, but there are 3 vertical reinforcement parts). So, the design meets the guidelines. Unfortunately the HDA prints showed that the on several areas the side boards were leaning outboard. One corner was completely disformed. Maybe we talk about 0.5 mm (over 2 mm). This is no way near the stated accuracy.
    Example 2:
    In one case the wheels were bended like the car was heavily overweight (technically not possible with this type of truck suspension, but that's a different story). The wheels only stick 1.4 mm below the axle and are 1 mm wide. The axle is 1.3 mm in diameter. Again, this design meets the design guidelines with a big margin. And again the deformations were a lot larger than the guidelines promise.
    Example 3:
    [​IMG]
    The ladder chassis of the truck is 17 mm in length. The beams measure 0.8 mm in width, 1.1 mm in height. In all cases the chassis was bent.

    So based on these findings we should have received a third re-print of this model?

    Based on the design guidelines and SW's answers the vast majority our current car models should be printable in B-HDA with more or less the same geometrical results as in FUD/FXD. Is that correct?

    Regards,
    Maurice
     
  8. woody64
    woody64 Well-Known Member
    Other colours I would also very much appreciate (at least as long black stays).Grey would be definitely a good choice.
     
  9. cbfasi
    cbfasi Member
    Just had my first print in this material, not impressed is an understatement.
     
  10. javelin98
    javelin98 Well-Known Member
    One of the problems appears to be with how SW techs are changing the orientation of the models to maximize print space. I understand why this is important, but it plays havoc with designers who are trying their best to follow the published guidelines. I still don't understand why one of my products, which had no undercuts and was connected by a sprue that would have sat flat on the print bed, was rejected, other than a knee-jerk reaction to the word "sprue".

    It might be that BHDA is suitable mostly for large, thick, single-part models. That's fine, but SW should tell us that so that those of us in the miniatures business don't waste our time trying to design for it.
     
  11. mkroeker
    mkroeker Well-Known Member
    Mind expanding on what went wrong, so that we (and they) can learn from it ? (Depending on what it was, emailing service@shapeways.com with your order number and a photo of the defect(s) may get you a reprint)
     
  12. Syncrasis
    Syncrasis Member
    I've recently received my HDA model, my model is quite a bit larger than what you guys seem to be printing and I'm rather impressed with the results. The techs did a great job choosing backsides for the support material and the surface quality is very good. You can see the size compared to my hands, my hands are rather small.

    I'm printing organic figurines so warpage isn't something I'll be able to comment on, as I can't tell.

    [​IMG]

    This is a bobblehead figurine. I saw some tool marks on the left arm (the one that's separate from the body) and stippling where the support material was, but overall this came out quite nicely. To compare with FUD:

    [​IMG]
    FUD, while having a superior surface quality in some areas (no stepping at all!), definitely required more cleanup work. The stippling on the HDA was easy to see and sandpaper off, while the FUD had that chalky material on the backsides and in crevices that was a pain to clean up. The only place I have trouble with is inside the mouth. There is some support material in there that's difficult to get at.

    In my case, I prefer the HDA over the FUD overall.
     
    Silvanus and Andrewsimonthomas like this.
  13. davemc
    davemc Member
    Can I use BHDA to print a cylindrical tube outer diameter - 4.5mm, inner diameter 2.7mm - wall thickness - .9mm , length 50mm ? I have printed it with FUD.
     
  14. mikepenn
    mikepenn Shapeways Employee Manufacturing
    That sounds ok, but we can not guarantee orientation when we print, so the support marks may be on the side of the cylinder. We try and explain what needs to change if we have to reject it.
     
  15. woody64
    woody64 Well-Known Member
    Seems that the rejection cycles once more have started. Would have been able to earn a significant amount of money this weekend but all objects where rejected caused by bearers. The same kind of bearers were used for another set of 20 items showing a success rate of 100% today morning. Later on today there were only some left, the rest was rejected since it wasn't successfully printed.
    Although I have tried to discuss that in the beta user testgroup and with some SW employees to find a good bearer solution it seems difficult and has caused me to make design changes and uploads of several dozens elements at least three times. As also mentioned before this material is well accepted since it's smooth, but no one is willing to add $5 handling costs. So there is a need of bearer or the material is not usable for a lot of models.
     
  16. Silvanus
    Silvanus Well-Known Member
    Really cool figurine, Syncrasis. :)