Prototyping – Introduction

Dictionaries seem to agree that a prototype is the earliest defining instance of a thing or class of things. So, for example, the Ford Model T is probably the prototypical mass-produced car and Hancock’s Half Hour the prototype for all British TV sitcoms. But the meaning is a little different in the world of manufacturing, where prototyping is part of the development process of a product: a prototype doesn’t define the product, but it helps us get there. Although we have several names for the things that get made in the run-up to production – models, mock-ups, rigs and samples – it’s well understood that a prototype is a robust, functional construction that’s configured a lot like the product-to-be. It’s constructed so we can find out if, and how, the thing works, and is often part of an iterative sequence, with each step leading to improvements in the next.

Engineering prototyping began with industrialisation, and was initially a fairly straightforward proposition. Use more or less the same materials as you would for the production item, and although there may be more handwork involved in making it, the prototype would be a convincing stand-in for the future product. That all changed with the advent of thermoplastics, materials which could only be formed using high-investment, mass-production processes. The prototyping principle became deeply compromised; with plastics it was impossible to make prototypes that would perform exactly as their successors would.

To compound the problem, these thermoplastics technologies enabled designers to create products with far more geometrical freedom than was possible with earlier, mostly metals-based techniques. Things could be a lot curvier, and plastics also made it possible to incorporate multiple functional features like hinges into single mouldings. Prototyping became a hugely expensive and time-consuming craft process, and it was actually impossible to make a proper prototype that could reliably prove a design was right.

In 1986, US start-up 3D Systems announced its first product – Stereo Lithography Apparatus 1 – and rapid prototyping was born. Now you could prototype plastic parts, in curvy shapes and with complex details, quickly and fairly accurately, even if you couldn’t make them in the right plastic. Rapid prototyping is now commonplace, with many competing technologies and suppliers. Detail resolution, surface finish, speed and materials are improving fast, though these still fail to faithfully reproduce production standards. But progress is accelerating, driven now by the realisation that the principle of fabricating parts and ‘growing’ them directly from digital data will become the platform for rapid manufacturing. And rapid manufacturing may ultimately transform manufacturing, not just the prototyping bit.

Geoff Hollington, Designer and technologist