Feb 16, 2017 | By Benedict

Engineers from NK Labs and JACE have used 3D printing to create the STRAW, a massively overengineered multi-hole drinking straw designed to suck evenly from each contrasting half of the new McDonald’s Chocolate Shamrock Shake, made to celebrate St Patrick’s Day.

When you’ve worked on engineering projects for Google, NASA, and DARPA, where do you go next to fulfill your creative ambitions? Apple? Facebook? 3D Systems? No, you go to McDonald’s. After helping to create Google’s Project Ara modular smartphone, Massachusetts-based NK Labs and San Fran’s JACE Design were looking for a new challenge, one that would push them to their limits and help solve real-world problems along the way. That challenge came in the form of McDonald's new dual-layer Chocolate Shamrock Shake, a limited edition St Patrick’s Day milkshake that consists of a chocolate bottom half and minty green top half.

The brief was clear: ordinary straws don’t let you suck in both the top and bottom halves of a milkshake, so NK Labs and JACE needed to make a device that could. Simply using two straws, one long and one short, wouldn’t work—as soon as the milkshake was half-finished, the shorter straw would end up sucking in air. And simply stirring the shake would create a totally different (and clearly inferior) drinking experience. The project, titled STRAW, or Suction Tube for Reverse Axial Withdrawal, would be a long and difficult one, but the team was ready to do its best to delight dairy drinkers.

After lots of thinking about the straw-to-be, the design team realized that the only way to create the perfect STRAW would be to incorporate multiple holes, allowing the drinker to suck from the top down rather than bottom up. To do this, they created a J-shaped instrument with three extra holes that would allow the mixture to be sucked from various points within the cup. “It’s one of those things that seems so simple, but as we got into it there were a lot more issues exposed,” said Seth Newburg, principal engineer and managing partner at NK Labs. “It turned out to present quite a few engineering and scientific challenges.”

When making prototypes of the STRAW, NK Labs and JACE even used 3D printing to realize their hopeful CAD models. These 3D printed straws could then be tested with fluid dynamics simulations, water and oil playing the part of the two halves of the limited edition milkshake. When the team got closer to the final design, they ordered 100 Chocolate Shamrock Shakes, keeping them in the freezer, and conducted tests with the one-off beverage to fine-tune certain aspects such as hole size and straw diameter.

The STRAW may not be perfect, but the team believes that the unique J-shaped sucking device is much better for sucking an even mix of the two substances than a regular drinking straw. “At some points when you’re drinking it, you can get an exact 50-50 mix of the flavors,” Newburg said. “But with the different conditions: Full cup, nearly empty cup, depending how much it melted, you could get some slight variations. But we made sure that you're still getting both flavors all the way through.”

Look out for the STRAW as St Patrick’s Day draws near. The instrument will be distributed for free in McDonald's restaurants across 80 cities over the next few weeks, in a run of 2,000 straws. More could be made if the STRAW becomes as popular as we think it might.



Posted in Fun with 3D Printing



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