Limitation and Inspiration
Some truly amazing designs come out of designing for developing countries. An organization called Kickstart makes water pumps, oilseed presses, and other tools for small farmers to boost productivity.
The products look clunky at first blush, but the numerous constraints placed on the design have dictated a design that would be near impossible to create with Solidworks and an FDM machine. What would you do if you had to create a human-powered pump or press that cost about sixty dollars retail, produced with cheap steel stock and stick welders, and could be field-serviceable anywhere? This is the kind of task that "first-world" designers might dismiss as trivial, until details like seals, bearings, and design for manufacturability come into play.
If you take a glass-is-half-full approach to design constraint, it can be a psychological boost. There's a huge difference between designing for NASA, where pretty much every technology known to humans is fair game, and designing a cheap water pump. For the space shuttle program NASA engineers had to pick between different rocket fuels, different form factors (reusable orbiter, disposable rocket, giant catapult) and different computational platforms. Every option in a project that complex has a cascade of other decisions surrounding it. If we make the rocket motors parachute back to earth, how does that affect the weight? Do we have to decrease payload size? Will we have to make the motors bigger? On the opposite side of the spectrum, an African pump designer has a very limited palette. What's strong and durable? steel. What's available as a waterproof seal? oiled leather, and rubber. But don't count on rubber being available, unless it's a bicycle inner tube. What can we use to attach it? Bolts are hard to find, but there's a guy in Nairobi with a stick welder and a ton of enthusiasm. What power sources do we have? No electricity, and a two-stroke engine isn't going to be serviceable by a farmer. We'll have to use the farmers themselves. Every technology that's inaccessible is a technology you don't have to worry about. You can then spend your time dreaming up innovative geometries and shaving away percentages of efficiency rather than trying to get that Ethernet connection to interface with the LED display, and worrying about whether a touchscreen would have been better.
With some products that have been around for a long time, you can see how design
constraints have winnowed the product down to a very consistent design, regardless of manufacturer. Bikes are a prime example. We've come through a century of development that introduced plastics, cheap computation, and mind-blowing adhesives. Despite this, the design of a bicycle one hundred years ago and today are very similar. There are only a few ways to build a wheel that can withstand lateral loads and be stiff and light, only a few geometries that provide the strongest way to link a fork, seat, pedals, and rear wheel together. Every bike designer dreams of creating some new way to expand functionality, but big design changes are rare. A bike mechanic from 1930 would probably be able to service most of a modern bike
(with some exceptions). Most of the advancements take the form of focused improvements on existing parts - innovation rather than invention. Each part exists to execute a very specific function, which prevents the designer from introducing anything very different from what's out there. Instead, each part is improved upon incrementally to get something amazingly efficient and serviceable. Some of these constraints are disappearing with the advent of cheap carbon fiber, disk brakes, and demand for folding bikes. It will be
interesting to see how long the current search for The Perfect Carbon Fiber Bike Frame will last, and when a new form is accepted as The Way A Bike Should Look. Even when the constraint of steel tubes is replaced with the freedom of carbon fiber, designers will still need to deal with most of the same issues as before. Knowing the enthusiasm of bike engineers for creating within limitations, they will keep making tiny changes, and loving the process.
Next time you're presented with a set of design requirements that seem absurd or just plain annoying, try to face them with enthusiasm. This is an opportunity to
simplify your design, or to create a clever mechanism that has an exceptional wow factor to it. You don't have to feel like it's compromising your design, but rather presents you with a well-defined space within which to create.
Copyright 2004-2006 Dominic Muren and IDFuel Team