Additive Manufacturing

SEP 2018

ADDITIVE MANUFACTURING is the magazine devoted to industrial applications of 3D printing and digital layering technology. We cover the promise and the challenges of this technology for making functional tooling and end-use production parts.

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Page 34 of 43

AM / Stepping into Production 33 certainly faster than waiting for tooling, but also faster than many other 3D printers. "With these printers, you might print something in 10 minutes, versus several hours with another process," Good says. However, the speed comes with a trade- off. Once printed, most resin parts require between 4 and 13 hours of thermal postcure in an oven—sometimes a surprise to customers. "Managing expectations was a challenge in the beginning," Good says, but the time savings are obvious when the production timeline is taken as a whole. Rather than wait several months for tooling and parts, customers can have the parts within a week. Part characteristics. Another advantage of the CLIP process is that the print doesn't pause between layers, but continuously pulls the build platform upward as resin flows through the deadzone. This means a smooth, watertight surface finish with no tell-tale layer lines, but also something more: isotropic properties. The 3D-printed and cured parts are said to be equally strong in all directions, comparable to injection-molded parts. Production-capable materials. One of the things that drew TTH to this technology originally was the durable urethane materials available. "Materials are the backbone, the core of the whole thing," Horner says. "If you don't have the materials for production, you can't use it for production." Carbon's catalog today includes about 15 materials. Some are "one-part" materials that are UV-curable, but most are "two- part" materials that require a second cure in the oven to achieve their final part properties. TTH prints with all these available materials except the dental resins. Its most commonly used materials are RPU 70, a rigid polyurethane that is UL-rated and biocompatible, and EPU 40, an elastomer suitable for applications including gaskets and "overmolding" by printing onto an existing build to create flexible features. Increasing automation. Whereas manufacturers have had decades to streamline and finesse CNC machining and injection molding, 3D printing still requires a fair amount of human intervention—introducing opportunity for human error, Brent says. The SpeedCell system offers a few features that help take some of that burden away from operators. One is integration with the meter, mix, dispense (MMD) unit for dispensing printer resin into a reservoir, called a cassette, for installation into the printer. To weigh out the resin by hand takes as much as 25 minutes of human work and attention, but the MMD unit dispenses the proper amount of material in less than 5 minutes. Carbon's Smart Part Washer represents another significant labor-saving concession. "Before getting the washer, we weren't running the printers at capacity because cleaning the parts by hand took too long," Brent says. Now, employees can load completed build platforms into the washer to be cleaned with a solvent in 7 to 9 minutes. Current Success and Future Growth The Technology House is currently capable of turning out about 1,500 parts per day with the SpeedCell setup. While pro- totyping is still a common application, there is a trend toward One way the SpeedCell system supports production is through automating labor-intensive steps. Build platforms can go straight from the printer into the Smart Part Washer for cleaning within minutes. customers pursuing production with this technology, and the company increasingly finds itself manufacturing parts that can actually be improved by virtue of being made with 3D printing. For instance, the company recently worked with Vitamix and Carbon to redesign a nozzle used to clean Vitamix blenders in commercial settings. TTH was able to condense the original six injection-molded parts that made up this nozzle into a single 3D-printed piece. The 3D-printed part uses 30 percent less ma- terial and is 10 times more durable than its predecessor. Given successes like this, The Technology House only sees the use cases for its 3D printing equipment growing in the future. When the company first purchased its Streetsboro fa- cility in 2015, the plan was to consolidate both The Technology House and Sea Air Space under one roof. But after bringing in Carbon 3D printing technology, plans changed. The open space in the facility is now reserved not for consolidation, not for bringing machining under the same roof, but instead for future growth in production AM. These nozzles for clean- ing Vitamix blenders were redesigned to take advantage of the CLIP process, condensing this component from six pieces down to one. The 3D-printed nozzles use 30 percent less material than the legacy parts while also offering great- er durability.

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