Paper prototyping makes a comeback

The new Irish Mcor Matrix machine is a fresh take on the idea of Laminated Object Manufacturing, but produces much better quality models and uses cheap, ordinary sheets of A4 paper - and eco-friendly, water-based adhesives - to produce models that can include living hinges.
Developed by brothers Dr Conor and Finian MacCormack, it is designed to work with sheets of 80gsm photocopier paper (although it can take in printed waste paper, provided it is in the form of a pile of flat sheets), producing models at a fraction of the cost of most of its competitors. Unlike the models produced by the original LOM machines, which looked as if they had been made of piles of paper stuck together, a screw top bottle and cap shown to Eureka at the TCT show showed no signs of layers, and also screwed together and unscrewed like the real thing. Conor MacCormack then unveiled a small enclosure, with a living hinge made from a single paper sheet. Most RP technologies currently available would find this impossible to make and it would be extremely difficult for the remainder. A tungsten carbide tangential blade, with a tiny tip that is free to swivel about its axis, cuts the sheets. It is adjusted in 50 micron steps until it just starts to score the paper. In the case of 0.1mm thick paper, it is advanced down by 0.15mm, so that it cuts right through the top sheet, and starts to score the next. The same head loads the sheets of paper, and cuts and glues them with PVA water-based adhesive. “The thing we thought would be easy was applying the glue to the paper,” states MacCormack. “If we had decided to use solvent-based glues, it would have been easy. If you drop water onto paper it blisters, but we were determined to stick water-based glues and our main intellectual property is in the glue application technology.” The adhesive is applied fully in areas that are to form parts of the finished models, and sparsely in areas outside, to make waste removal easier. With the original LOM machines, he says, “it used to practically take a chisel to break the waste away, destroying any delicate structure”. Development took some time. The company was started in 2002. Conor MacCormack was then a lecturer at Trinity College and brother Finian was in the United States, working on wire bonding machines. Finian was responsible for the software and electronics, while Conor took charge of the mechanics and materials technology. “The concept was to make something that was low cost and entry level,” Conor MacCormack explains. They went full-time on the project in 2005 and have now sold five machines. The sixth was brought to the TCT show in Coventry for its UK launch. The sale price is 24,959 euros – “perhaps 3,000 to 4,000 more than the competition”, Conor MacCormack concedes, but the big advantage is being able to work with ordinary paper, which is a small fraction of the cost of the special resins and other materials used by almost everyone else. Models straight out of the machines have the appearance of a woodcarving, but can be finished with a Cyanoacrylate that not only gives a smooth, shiny finish, but also increases the life of the part. Pointers * Machine works with 80gsm A4 sheets of paper, which can be printed on waste paper, provided it comes in the form of a pile of flat sheets. * Media costs are a tiny fraction of those of competitors * Max build dimensions are 297 x 210 x 150mm and resolution is 0.1mm in the Z-axis - the thickness of a single sheet of paper