Designing in the digital and physical worlds at the same time
WHEN great designs are turned into products compromises are made. The beautifully sculpted “concept” cars that regularly appear at motor shows never get built, at least not in the form they left the design studio, because they are inevitably too difficult and expensive to engineer for mass production. For decades this has meant products have had to be “designed for manufacture”, which essentially means their components must incorporate features that can be readily shaped by machines in order to be glued, screwed or welded together by people or robots. Now a combination of powerful computer-aided design (CAD) software and new manufacturing methods is changing the game.
Instead of being created with technical drawings and blueprints, most new products are today conceived in CAD systems in a three-dimensional virtual form. As these systems get cleverer some of the design processes themselves are being automated: algorithms suggest the most efficient shapes to save weight, or to provide strength or flexibility according to the loads and stresses placed upon them. Components and even entire products can be tested in their digital form, often using virtual reality. When something physical is finally built the same software drives the equipment that produces it, whether automated lathes and milling machines that cut and drill material or, in the case of additive manufacturing, 3D printers that build up objects layer-by-layer in a way never before possible.
This digital dimension gives designers a greater level of freedom to create new things (see article). But not all designers are skilled in using CAD systems. Even those who are might want to set aside the computer mouse for a saw, a file or a welding torch to get hands-on with their ideas. The ability to do both is becoming possible. A machine developed at the University of Lancaster in Britain provides a glimpse of a future in which product designers will be able to work in both digital and physical forms—at the same time.
The ReForm is a desktop machine developed by Jason Alexander, Christian Weichel (now at Bosch, a German components group) and John Hardy (now co-founder of HE Inventions, a Manchester startup) to pick up any changes made to a physical model of a product and reflect those changes back into the digital model, or vice versa. “I like to think of it as the closest implementation yet of a Star Trek replicator,” says Dr Hardy, referring to the device that could create just about anything in the science-fiction TV series.
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Inside ReForm is a fast-spinning milling head, which cuts shapes out of material in the traditional subtractive manner, and a 3D-printing extrusion head, which builds material in layers up additively. Overseeing proceedings is a 3D scanner, which projects a pattern of light onto the object being worked upon. A pair of cameras, positioned in the machine at different viewpoints, detects minute differences in the pattern of light reflected from the object to determine its shape in a digital form. At present the machine works with modelling clay. That might seem a bit old-fashioned, but it is still widely used: despite all their new digital tools, car designers, for one, continue to make full-sized replicas of new models in clay.
The machine can be used in a number of ways. A digital CAD design can be sent to ReForm and it will set about milling it from a block of clay or printing it, after the machine itself determines which process will be the fastest. It could be a combination of both. Alternatively, an object can be placed inside ReForm to be scanned, after which a replica will be made either additively or subtractively.
Changes can then be made to the object, cutting a bit off here, say, adding a bit there or drilling a hole. That could be done virtually on a computer screen or by removing the physical model and doing the work manually. Once placed back into the machine, the scanner detects the changes and updates the digital model.
An image of the object is projected onto the viewing window at the front of the machine. This allows a designer to view the digital version overlaid on the actual clay object inside. It is used to produce a digital preview of what any changes will look like before cutting or printing begins. And if a designer thinks he has really messed up, there is an “undo” button which will let him scroll back through images of previous iterations, choose one and leave it to the machine to return the object to that original state.
Machines like ReForm will allow people with no technical knowledge to engage in product design, says Dr Alexander. With further development, he believes it will be possible to integrate other manufacturing techniques into ReForm, such as making things in plastic or metal or at much larger scale, with milling and extrusion heads mounted on robotic arms.
One intriguing possibility the team is thinking about is 3D printing electrical circuits, a process that is just beginning to be used in some factories. 3D-printed electronics would give ReForm the ability to make prototypes and even one-off products that are more functional. And it could also be used to follow up the software updates that many devices now demand with hardware updates, too. This would be done by putting a mobile phone, say, into the machine, cutting out a previous version of any circuitry and printing new electronics in its place. With a machine like ReForm it might no longer be necessary to throw any device away.
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