Protomold president Brad Cleveland believes that the mechanical properties of plastic parts made on additive machines don't come close enough to those of injection-molded and machined plastic parts, which creates design engineering difficulties. So Design News asked Cleveland to back up his assertions about material properties — and he did. Protomold hired an independent materials testing lab, Stork Materials Technology, to run ASTM tensile and flexural tests of three kinds of ABS parts — injection molded, CNC machined and fused deposition modeled (FDM) — on a Stratasys machine. The study tested the FDM part in different orientations to account for the anisotropy found in additive parts. It also tests the molded part in two different gating configurations. The study, whose results are summarized in these tables below and which can be downloaded in full here, shows a significant strength advantage for machined and molded ABS grades.
The choice between helical and spur gears in gearboxes may seem straightforward. But with planetary gearboxes, however, the choice between helical and spur gears requires some additional thought. Here’s what you need to know to make the right choice.
Cas Smith is a biological engineer at Terrapin Bright Green, a consulting firm that specializes in green and sustainable design. At the core of his work is to explore how biomimicry can inform sustainable design. He discussed biomimicry and its implications for design and solving some of the world’s sustainability issues in an interview with Design News.
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