3D Print in Nylon with Selective Laser Sintering – Part 1

This is the first in a series of 3 posts about 3D printing in nylon with Selective Laser Sintering. Click on the links to read part 2 and part 3

It’s now been almost six years since we started offering White Strong and Flexible (WSF) to you, our community and it’s a good time to share what we have learned.

So, this is the first of a series of three blog-posts that I am writing about Strong and Flexible 3D-printing. Please share your feedback by commenting, we would love to learn your thoughts and ideas!

First and foremost we are extremely happy to see the result of what you have made with WSF and later the color variants (together called Strong and Flexible Plastic). Over the last six years we have printed more than 2.5 million parts in Strong and Flexible. These part range from jewelry to cases for the iPhone, quad-copter accessories (see picture), to the fabulous Animaris Geneticus Parvus (see picture), lighting shades and more.  White Strong and Flexible Plastic and the colors have been and are still by far the most popular material on Shapeways.

Animaris Geneticus Parvus

3D print of Animaris Geneticus Parvus or Strandbeest

DJI Phantom accessories

3D printed DJI Phantom accessories

Let me share what it means to make something in Strong and Flexible Plastic. The current system on Shapeways is based on files. After you buy 1 or more copies of a product represented in a file, the work for us starts.

First, for new products, we have to check whether the products in the file are printable. Are the printers capable of producing the details? Are the products strong enough? Are the walls thick enough? Checking each new file is done by software and by hand to make sure you get what you want. If we believe we cannot print something, our team makes a clear report about the issues, including screenshots. As you can imagine this takes quite a bit of time. The checking and rejection process has become quite a challenge, more about this in the post next week!

After checking we plan the files into the tray of the machine. Depending on the size of the machine, each tray can hold hundreds and sometimes thousands of products. If the files hold multiple parts, here’s where it becomes hard. We sometimes need to increase separation of the parts (to prevent them to melt or fuse together) or reorient or simply separate them to optimize maximum tray fill. As we put more parts in a single tray, it increases the efficiency of the print run and in turn enables us to offer reasonable prices.

Now that we have planned the tray the file containing all parts for the print, called a slice file, is sent to one of our big SLS printers (picture below shows one of our massive EOS P7s). One printing run typically takes 24 hours, but our big P7 machines can print for up to 3 days! When the printing is done we quickly remove the full tray to let it cool. Cooling takes as much time as printing.

EOS P7 SLS printer in Shapeways factory at LIC

EOS P7 in our factory at LIC

After the tray is cooled down to room temperature, we retrieve the parts from the tray, which is now filled with nylon powder and parts. Digging the parts out of the powder one by one is actually a super fun process. You never know what you are going to find! The hardest to find are the very small parts, since distinguishing them from little plastic lumps is challenging. At one time someone tried to print parts as small as 1x1x1 mm!!

Now we need to remove the excess powder from each part, which is done with compressed air. Then we sort all parts. Some will be ready to go to our packing stations and be shipped, while others need post production. We either polish (see pic below of our polisher), or polish and dye the parts. After each step we need to sort again, since polishing and dying puts all parts together in batches again. So we spend a lot of time sorting parts and luckily we have gotten quite good at it ensuring everyone of you, our customers, get the right parts with the right finish. Files holding multiple parts are hard to sort. Our systems use the file as the unit and if it contains multiple parts its hard to recognize and to make sure we have all parts. Some files hold over 100 parts and even counting them takes a lot of time!

Shapeways Polisher in LIC

One of our big polishers at our LIC factory

We can typically do all the above steps in less than four days, which is quite miraculous given the amount of time the printing itself takes. Once all of these steps are complete, the products are ready to ship and are collected in the distribution wall of bins (see picture below). When the order is completed, our distribution team packs them up and sends them to you our customers to enjoy.

Shapeways Distribution Area wall of bins

Our distribution area with the bins holding parts ready to ship

Next week I’ll spend time diving a bit deeper in the specific challenges we face and how they influence the cost of 3D printing in nylon using Selective Laser Sintering.

Please feel free to ask questions in the comments below, or make suggestions for the deeper dive next week!

all the best,
Pete / CEO Shapeways

This is the first in a series of 3 posts about 3D printing in nylon with Selective Laser Sintering. Click on the links to read part 2 and part 3

14 comments

  1. mm

    how much does an SLS printer costs?

    1. pete Post author

      The SLS printers we currently use range from $140k for a small one to $ 1 million for the largest one (the P7 see picture above)

  2. Gael Troughton

    Hey Pete, I have you guys print HO scale model railroad kits for my company, Mokelumne River Models. Are you guys working on a way to reduce the powder/dust that adheres to the parts? Some parts in the same print have a lot of dust, others are mostly clean. I’ve tried a Solvent called Bestine, with minor success, and stiff brushes, but the most successful technique is physical scraping using an Exacto hobby knife, which takes a great deal of time. I do not want to send out 3D kits to my customers with the adhering dust! I have fully embraced this technology for my kits, but hope to see improvement in the dust issue.
    Best Regards,
    Gael

    1. pete Post author

      Hi Gael,

      good question and cool to hear you are making your business work on Shapeways – exactly what we want to enable!!
      The powder sticking can be caused by two reasons.
      1) Not enough air blasting – for amounts of powder that can be shaken off or easily blown off. (this does not seem the case for you)
      2) Machine settings – if the powder is really sticky, it could be the build settings were slightly off. In that case the powder can “bake” on whilst it is not supposed to.

      In both cases you should let us know ALWAYS and we can learn and help you.

      Pete

  3. Iñigo Gonzalez

    Hi.
    A year ago I ordered 4 pieces in WSF, it was not an own design, it was a repair.
    The result was so satisfactory that encourage me to design and join Shapeways.
    In my design is very important the accuracy of the pieces for the correct assembly.
    I did tests to achieve the final design. The pieces are 5 mm thick.
    Following your advice on how to lower the designs, I made the pieces 1mm thick on all sides, and two holes for evacuation. The result was incorrect pieces, failed tolerances. My opinion is that they do not have the material to support it, the material collapses inward, because, I think, to its flexibility.
    Furthermore, all orders (solid pieces) after I’ve done have been perfect with correct measurements.
    Another thing I wanted to tell you that , in another company like Shapeways , I read that SLS is foodsafe. It surprised me a lot.

    thank you for the blog, and have a nice day.

  4. Gael Troughton

    Thanks, Pete, I appreciate your explanation on how the powder can attach itself. I do currently have a large order at Shapeways, and would like to have this information communicated to your print techs. How do I communicate these concerns to them, on my print orders?

    I get very positive comments from my customers on my 3D print model kits. It’s the way to go for creating model kits!
    Best Regards,
    Gael

    1. HUGO Ploegmakers

      Dear Gael,

      Thanks for your enthusiasm! We’re always happy to receive input from our customers!

      Could it be the order you are referring to is in Frosted Ultra Detail (FUD)? This material has its specific challenges to remove the supporting wax. We are internally researching methods to guarantee more consistent cleaning. I’m looking forward to roll this out to customer models – but we need to do a bit more experiments internally before we can guarantee that it will work for all the different model types we receive!

      regards,
      HUGO
      (Director of Operations, Shapeways Eindhoven)

  5. s_f_x

    Hi,

    you emphasized that files with multiple objects are tricky on your end. I often end up putting multiple parts into one STL, for two reasons:
    - I prefer having all parts for one project in one “Model” on my shapeways account to avoid cluttering, make it more convenient to order the correct amount of parts, and also it’s a tiny bit cheaper as the setup fee is only added once in the “new” pricing system (after initially just paying volume where it was the same).
    - When someone else orders my designs, it’s better to have all parts in one to avoid people forgetting to order the other parts. However, I’d like to be able to put it up as a complete “kit” with all parts, and the parts individually as well for spare parts.

    I did have occasional issues with parts not being shipped in multi-part files, particularly (as I was told) if they are not clearly visible in the preview render (which I assume serves as your reference). I tried to arrange parts clearly next to each other to make it easier, but that often increases the bounding box which would cost more due to “low density”.

    Here is a suggestion:
    How about adding a “group” or “kit” feature to the website, to be able to upload multiple files (one part each) to the same design? That way we get the convenience of having it all together, and you can track each individual item more easily.
    Each multi-part design would appear as a single item in the overview, but when clicking on the Model, there is an option to order the complete kit, or just pick individual parts for spares. Ideally the price for the complete multi-part kit would be the same as putting all parts into one file. Future features could be that the designer can assign material combinations for the kit (e.g some parts in metal, or detailed plastic, or different colours), with the option to define multiple combinations that go together.

    1. Peter Weijmarshausen

      Hey s_f_x,

      great suggestion! This Wed the second post of the series will go live and I will definitely talk more about multiple parts. Stay tuned and you may be surprised :)

      Pete

  6. Justin

    Thank you for the info on how this technology works! I have had ZERO complaints about anything I’ve had printed in nylon. I think some readers may be confused about which 3d printing technology you are describing here, and that different materials require a different machine and process.
    Your consistency has been amazing. I have only once had a small piece missing from an order, and you guys corrected the issue as soon as I let you know.
    Your prices are great and I hope you have many years of success ahead.

    1. pete Post author

      Hi Justin,

      thanks for your feedback. Glad to hear you are happy!
      We are working hard to make things even better.

      Pete

  7. Alex Kaufman

    Would it be possible to further automate the process of cleaning and sorting the nylon powder block on the backend by loading the blocks into something akin to a large sieve – perhaps on a conveyor belt? It would seem that the sorting process is an onerous one of decreasing returns, since you’d be making the least revenue off the pieces that are hardest to find, so it may justify (at some scale) the implementation of an automated sorting system – at least one that could sort by size. Since you already have the 3D render of every object in the nylon block, you could in fact close the loop entirely by implementing an object recognition system inside the sorter that would route and package every object. The manual work would then largely consist of sorting anything that’s missed by the system and being ‘on the loop’ rather than ‘in the loop’. Just an idea for how you could achieve even greater economies of scale, which I’m sure you guys are probably already thinking about.

  8. Thinker Thing

    Great to see this sort of post from you Pete. Were big supporters, we just received some interlocking pieces in WSF, as usual we knew we were pushing the limits but were blown away that’s these tiny frames didn’t warp and interlocked together perfectly. Great customer support above and beyond the call of duty, and great work by Aimee Moyer and Eleanor Whitney. Keep it up as you become ever bigger. Would love to see the same insights on metal printing process and the new color plastic, and what you see the challenges are for the future.

    1. Pete

      Thanks and will add your suggestion on future blog post in my list :)

Comments are closed.