Tolerancing software cuts rework levels
Paul Fanning reports on software that could put the manufacturing engineer's experience on the design engineer's desk.
Software that can eliminate tolerancing faults at the design stage could save companies huge amounts of money in terms of scrap and rework at the manufacturing stage. Tolcap is the brainchild of Martin Raines and Ken Swift of Capra Technology and is now available as a web-based software application thanks to a collaboration with web developer clever4.
Dr Raines outlines the scale of the problem it is designed to address, saying: "One of the main causes of faults at the manufacturing stage is the wrong application of tolerances. The problem is that manufacturing departments want wide tolerances, while designers want tight tolerances – often with no regard for whether it can be manufactured.
Designers design and then throw it 'over the wall' to manufacturing. The problem is that, when it comes to manufacturing, it can't be made consistently. And the later you have to make a change, the more costly it is." Given that 30-50% of scrap and rework is caused by poor tolerancing, the seriousness of the problem is clear.
Tolcap, claims Dr Raines, "puts the manufacturing engineer's expertise on the designer's desk", allowing them to arrive at a realistic and manufacturable tolerance. Tolcap provides capability maps for more than 80 different manufacturing processes that allow the user to pinpoint the most efficient production method by examining alternatives for cost and capability.
The software asks the user for a dimension and tolerance and returns a predicted process capability. The maps assume good practice in manufacturing operations, modern, well-maintained machinery and a design with no specific limitations set by material or geometry. Three Application 'Wizards' then take the user through modifications to the prediction.
The Mp Wizard allows the user to input information relating to the materials, while the Gp Wizard allows users to input variables relating to geometry. The Vp Wizard, on the other hand, takes into account additional variables such as machine age and the particular implementation of the process.
Of course, if a customer is using a material or process that is not covered by Tolcap's process maps, the company can work with them to collect data on a specific process that can either be added to the software or held as intellectual property of the customer and only used by that customer as part of Tolcap's bespoke software.
Early adopters of Tolcap included Rolls-Royce and Dyson. And it is partly through big-name manufacturers such as this that Capra Technology hopes that Tolcap will be popularised as it is rolled out to their suppliers. In companies such as these, of course, the great difficulty lies in making sure that, once adopted, the software is actually used properly.
Says Raines: "The designer should be using this as soon as they are putting the dimensions in. That is the challenge for us: to get it seamlessly within the design process. We tend to rely on 'champions' within individual companies to convince their colleagues…This is a unique product – there's nothing like it anywhere in the world. And, while engineers can tend to be conservative, this product can save them a huge amount of time and money."
Tolcap is available at a subscription rate of £245 per month, which allows two users to use it at any time. Additional licences can be bought at £95 per month.
