The bounds of tolerance

There's nothing new in design engineers getting assistance from IT. Think of the plethora of CAD CAM CAE systems launched over the years, the component libraries, etc, many now common on desktops. All have been designed to streamline the processes of product development – from concept to the shopfloor. By and large, they do a great job and have played a serious part in cutting costs and speeding innovation and competitiveness. But there has always been one fly in the ointment. No matter how good a job engineering believes it does, when it comes to manufacturing, some products fail. And then you're into significant rework and delays that cost companies dear. So it's interesting to come across software that goes to the heart of a key remaining problem – tolerance errors created at the design stage that remain undetected until too late. Tolcap is the brainchild of Dr Martin Raines and Ken Swift of Capra Technology, and is now available as a web-based application, thanks to collaboration with web developer clever4. As Raines explains: "Production departments want wide tolerances, but designers want tight tolerances – often with no regard for whether it can be manufactured. The problem is that... it can't be made consistently or it doesn't fit together properly." Research indicates that 30–50% of scrap and rework is caused by poor tolerancing, so Raines' big idea is to "put the manufacturing engineer's expertise on the designer's desk". It's about supporting a right-first-time approach to getting tolerances both optimised and manufacturable. Tolcap itself takes account of three main factors: the inherent capability of the processes available for production; critical dimensions; and material-to-process compatibility. For example, the software includes capability maps for more than 80 production processes that, importantly, allow a user to validate dimensions and tolerances, and to pinpoint the most efficient production method – assuming good practice and modern, well-maintained machinery. Three application wizards then take the user through modifications to get the desired result. One allows the user to input information relating to materials; another helps with geometry; and yet another takes account of variables such as machine age and condition. Early adopters include Rolls-Royce and Dyson, and it is partly through big-name manufacturers and their suppliers that Capra hopes Tolcap will become popularised. For others, though, that see a profoundly useful answer to prayer, you can try it free at www.tolcap.com.