Christian Brown

Design engineer & entrepreneur, passionate about technical challenges, great design and extended travel. Currently riding a motorcycle from Alaska to Argentina.

All articles from the author

Mechanical Design

Cutting Edge Design: Sharp Edges on Molded Parts

Sharp edges are beautiful: light glinting off these clean lines as a product rotates through space, music swelling dramatically in the background of a commercial. Edges are precise. Edges are distinct. Edges are horrible for injection molding. A general rule of injection molding is: Radius all edges. What do you do if your design calls […]

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Engineering

Side Actions to Produce “Impossible” Injection-Molded Undercuts

Design for injection molding has clear rules: Add draft. No undercuts. Round edges. Clear parting lines. Uniform walls, not too thick. But learning about advanced plastic manufacturing is like visiting Morpheus’s dojo in The Matrix: Some rules can be bent. Others can be broken. But breaking these rules is costly. Sharp edges require additional machining […]

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Engineering

Wall Thickness in Injection Molding

Heat and pressure most famously make diamonds. But they do more than that: Nearly every plastic product in your house was made with the same two forces. From the 1950s until now, injection molding has dominated consumer manufacturing, giving us everything from action figures to denture containers. Despite its incredible versatility, injection molding does have […]

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New Product Introduction

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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Testing & Analysis

Practical Guide to Prototype Testing

Aesthetic design is in the eye of the beholder, but functional prototypes have a different standard—testing—and for most of us, exam day has never been something to which we look forward. However, test day doesn’t have to fill you with the fear you felt going into high school Calculus exams: By setting clear design expectations […]

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CAD Modeling

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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Manufacturing Processes

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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CAD Modeling

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, […]

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Mechanical Design

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 […]

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Mechanical Design

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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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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Mechanical Design

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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Manufacturing Processes

How to Read Material Data Sheets

“I want this made of plastic,” he said, as if all plastics were the same. To most people they may be, but to an engineer, plastics come in families, have cousin materials, and have other materials that are as different as cats are from dogs. Of course, our clients expect us to worry about these […]

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Mechanical Design

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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Assembly

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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Mechanical Design

How to Design Assemblies to Be Self-Locating and Self-Fixturing

There’s a reason kids love Lego. When I was a kid, nothing was more valuable to me than my big blue bucket of the multi-colored bricks. Even when my parents encouraged my interest in engineering with more complex Fischer Technics, nothing replaced the joy of quickly snapping pieces together in increasingly complex shapes. Wouldn’t it […]

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Industry Insights

10 Amazing Engineering Jobs We’d Love to Have

No one becomes an engineer for the cubicle view. Whether inspired by inventors like Edison or falling into engineering because of math talent, we don’t dream of paperwork and taupe upholstery. Looking for more? Engineers at these great companies are changing the world and creating inspiring new technology. These are jobs we’re jealous of—jobs that […]

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Mechanical Design

Keep the Assembly Line Happy: 10 Design for Assembly Rules to Live By

“Perfection is achieved not when there Is nothing more to add, but when there is nothing left to take away” – Antoine de Saint-Exupery Your day isn’t going well when your boss quotes French novelists. In this case, my design was rejected under the accusation that it wasn’t “elegant”. What the heck was that supposed […]

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Mechanical Design

Holy FBD, Batman! Using Engineering Analysis to Improve Your Designs

A new engineer, I was getting used to the “excitement” of cubicle life when something (finally) happened. We’d stiffened part of our flow meters a month prior, and one of our customers started complaining about breakage. The graybeards upstairs were defending the change, while my engineering partner was struggling to explain why the minor tweak […]

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Mechanical Design

Hackable: Design for Disassembly in Electronics

All right, all right! I’ll confess: I’m part of the last generation to enter college without a cell phone—part of the last generation to graduate before iPhones were even on the market (Gasp! The horror!). My parents gave me my sister’s old phone as a sophomore, and I remember not wanting it, only begrudgingly accepting […]

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Industry Insights

Sustainable Packaging Design: Keeping Your Electronics, and the Planet, Safe

We’re insulated from the cost of our garbage in America. As kids, we were trained to carefully place trash in the cans lining our streets. I’ll never forget the shock of seeing that same trash scattered along the streets in urban West Africa, but it did get me thinking: They can see their waste. What […]

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CAD Modeling

Nothing Gets In: Waterproof Enclosure Design 101 (and IP68)

Design guidelines for waterproof enclosure design, as well as IP68 waterproof rating design.

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Engineering

How to Design Wire Guides That Are Both Functional and Beautiful

A robot climbing stairs was barely possible 30 years ago, but now, Honda’s ASIMO robot can not only walk up the stairs of an auditorium stage, it can play the violin. Honda uses ASIMO to showcase innovations in programming, electronics, sensing, and mechanics. And with its case off, ASIMO reveals craftsmanship in every detail, including […]

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Right on the Button: Using Button Design as a Showcase for Excellence

You’ve worked for months to get your prototype functioning. It’s time to take that ugly (but functional!) works-like prototype and create a real consumer product. Right now, you may be focused on the general shape, smoothing out the curves and accommodating the awkward PCB shape (darn those electrical engineers!), but soon you’ll feel the need […]

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Engineering

Strain-Relief: Design Tips for Durability and Aesthetic Appeal

You reach over to plug in your phone, and you feel that spark – and not in a good “I love this product!” kind of way. The wire is broken, and yet another charging cable is about to make its way to a landfill, while you have to make a midnight run to the store […]

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