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Durable 3D-Printed Mold Inserts Drastically Cut Bottle Design Costs and Time

Nexa3D cracks a tough problem

By Rain Noe - August 12, 2022

in Digital Fabrication

During my days as a structural package designer, when designing a new bottle, the last step for our department was to produce the CAD drawing of a new design. Then it went over to Engineering, who would tweak our CAD to produce the tooling drawing. Then we were ready to "cut steel," i.e. have the molds made for the blow-molding machine. That last step took months, and cost five figures.

That was in the '90s, and today you can have steel cut for a new bottle mold in about 4 weeks. However, Pepsi has figured out how to get that time down to just 48 hours, and with a cost savings of up to $10,000. It's staggering.

The way they do it is by not cutting steel at all. Instead they use a universal mold shell, then they 3D-print an insert that goes inside the mold.

People have messed around with this before, but the problem has been durability and cost. A 3D-printed ABS insert is nowhere near as strong as steel, and you can blow-mold maybe 100 bottles before the insert fails. Hardly worth your time and money, particularly since the PolyJet 3D printers required cost $250,000, the Digital ABS material you print with runs $422 per kilogram, and the prints can take three days.

To solve this, a research team led by Max Rodriguez, PepsiCo Senior Manager of Global Packaging R&D, turned to 3D printer manufacturer Nexa3D. The company used their NXE 400 Printer, an ultrafast machine "capable of printing at injection molding repeatability and tolerances, making it the fastest and most accurate production 3D printer in its category," the company says. It also costs just $60,000.

For material, the team used a polymer called xPEEK147, made by Henkel Loctite. xPEEK147 is tough, thermally stable and has high dimensional stability, and rings in at just $308 per kilogram.

xPEEK147

The new inserts were able to print more than 10,000 bottles before failing.

And the cost savings are significant:

- Compress prototype tooling development time from 4 weeks to 48 hours

- Slash prototype tooling costs from $10,000 to $350 per mold set

- Create durable tooling that can produce more than 10,000 bottles per mold

- Enable multiple design iterations to allow for timely verification of downstream activities

As a former package designer, I'm torn on this. I think it would've been so cool to be able to produce new bottle runs and design changes for small batches—new bottles for the World Cup and other major events. And I'm super-impressed with the technologies harnessed here. But then I start thinking wait…don't we have a plastic bottle problem?

In any case, you can read the case study for the above here.

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Comments

Einar Blixhavn

2 years ago

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The obvious route to make the inserts would be to cnc them out of aluminium. Their geometry let you do this as one-sided milling from pre-sized blocks.
In 48 hours, with a decent cnc machine, you would get a much better surface than the prints can provide.
If it is about prototyping, then standard abs will work, if it is about production run of 10000 bottles, the superior surface finish of cnc milled aluminium would be desireable.

The 3d printing technology here is cool, but I dont really see a benefit to use it to make these inserts.

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Max Rodriguez, PE

2 years ago

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Hi Greg,

The 3DP texture (stair stepping effect) can be significantly reduced through an automated post processing operation, which polishes the 3DP parts to a smooth finish. Visual comparison of bottles blown with this post process and polished metal tooling shows comparable bottle clarity and significant improvement on the stair stepping appearance. The post process takes 2-3 hours and it is fully automated. We are in the process of making production quality molds, which can potentially increase the output of the 3DP molds to up to 100,000 bottles, through mechanical electroplating. This will also help in improving the surface quality, while still keeping the cost of the tooling relatively low.
Rain’s write up is the best one I’ve seen on this technology. It is poignant, as it comes from an ID’s POV. IDs come from a Design Thinking approach. Engineers as myself approach it from a Systems Thinking POV. We intersect on the need at some point to prototype and test. I developed this solution with this need in mind. I am very glad to see that this solution is appreciated by the ID community.
Rain, this technology along with others that my team and I are engaged in is geared towards our sustainable efforts ad well as innovation, so please don’t be torn by this solution.

Thanks,
Max R.

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Greg Blonder

2 years ago

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In the case study it is clear from the photos that the bottle's surface telegraphs the 3D printing texture. Ok for protos, but in production? Also, blow molding is a low pressure operation- I doubt these inserts could withstand injection molding temps and pressures. Still, very cool.

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- Nathan Burley
  
  Greg Blonder
  
  2 years ago
  
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  When I worked for a Precious Plastic project in the UK we tested injection moulding (at 220C for polypropylene) into polycarbonate moulds inside a steel liner, that worked just fine. PEEK is significantly more temperature and pressure resistant that PC though! My co-founder designed a no-touch tool for COVID made from recycled LDPE injected into printed Nylon moulds. Those moulds lasted hundreds of injections at around 170C. I don't think they ever failed. Check the team out at Relic Plastic.
  
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