Kai Design Co

Mass Customization: The Future of Made-to-Fit Manufacturing

Once upon a time there were cobblers, who would craft shoes to individual feet. Then came the industrial revolution, and the cobblers were replaced by dozens of factory workers, each performing a single step to build standard shoes—and feet were expected to adapt. This wasn’t all bad; the new shoes were cheaper, and more people
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Let It Slide: Self-Lubrication in Mechanical Assemblies

We love the way friction gives us traction on the road, good brakes, and allows us to walk without looking like a newborn Bambi, but there are also things we can’t stand about it—engines seizing up, stuck bolts, and old grandfather clocks never chiming again. We absolutely need friction, and sometimes we absolutely need less
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Mechatronica: 3D Printing Gears and Robots

Designing and building robots and other mechatronic designs has been simplified by the continued evolution of 3D printing technology, but it’s not without its challenges. 3D printed parts aren’t quite the same as their more expensive machined and molded cousins, and we need to take into account the tolerances, surface finishes, and other limitations of manufacturing. But it’s well worth it:
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Scaling Up: From 3D Printed Prototypes to Injection Mold-Ready Designs

I love the invention and design development process. I love seeing the concepts come together, love working through iterations of prototypes and finally (finally!) getting a design just right, fulfilling all the technical and aesthetic requirements. But do you know what’s even better? Seeing your designs in full-scale manufacture. Unfortunately, once your design is beautiful
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Creating Involute Gears in CAD

Say you’re 3D printing a robot, and you’re designing a sweet gearing system to make your robot move smoothly. What to do about the fact that most CAD programs don’t have a “create involute gears” button? Welp, you’ll have to create these geometries manually. In this tutorial, I’ll walk you through the process in SolidWorks, and you can use
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Product Development Planning, from Product Idea to Manufacture

In an engineering utopia, every project would come in on time and under budget—and, of course, be delivered by a unicorn. Two of these are possible, despite all three being rare. But few projects are planned well, so we end up with unrealistic expectations and often don’t figure that out until the project is 80%
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How to Prototype Rubber Designs

When I began studying engineering, prototyping involved expensive machining and milling individual pieces after careful CNC programming (of course, back then, the GameCube was hot stuff, and GoldenEye on N64 still a fun way to pass a weekend). The first 3D printer I saw used inkjet printing technology, squirting glue over consecutive layers of sand—but
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How to Handle ECOs

Engineering Changes (ECs) are fulcrums: They’re powerful, and a small mistake one day can have incredible consequences for weeks, or even months, afterwards. When companies mature, they need systems to limit the impact of potential unintended consequences, but you’ll always hear engineers grumbling about the red tape required to make this “one tiny, obviously logical
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Slip Fit Tolerances and Geometry

We’ve explored interference fits and all their design limitations, but dowel pins have another application: slip fits. While interference fits create tight assembly tolerances, slip fits are just the opposite—they can easily give you a self-locating assembly, making manufacturing easier when needing close alignment. Want to know more? Read on! Slip Fit Basics Obvious from
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Too Tight or Perfect Fit? When to Use Press Fits in Your Assemblies

Adapting to many situations, holding parts in perfect alignment, easily introduced but forming a lasting bond—I could either be describing press fits or your favorite pair of jeans. Press fits have so many great features, you might wonder why they don’t replace all other connections. The truth is, press fits aren’t for every application—just like
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