Costly product flow reconfigurations 0; Virtual factories 1. Manufacturing process simulation is saving companies thousands of pounds. And software vendors are integrating CAD to product simulation, to test multiple physical stress scenarios, reducing costly prototype tests. Malcolm Wheatley reports on a convincing scoreline.
At Airbus’ factory in Filton, a decision to replace a machining line with a Flexible Manufacturing System (FMS) in 2009 posed some awkward questions. Machining pre formed metal billets of aluminium, titanium or steel shipped in from external suppliers, the line typically took up to 15 hours to finish a given part — having in the process removed as much as 90% of the metal originally contained in the billet.
Replacing individual CNC machines with an FMS made obvious sense, as did replacing the heavily manual machine loading and unloading processes with a rail guided modular multi level pallet loading transport system.
In effect a robotic crane going back and forth between the machines, it would collect billets — loaded into carriers called ‘cubes’ — from an interprocess storage facility, place them into the FMS, and then return them to the storage facility’s storage racks after the completion of each operation.
But how many storage racks would be required? How many cubes would be needed? How many loading stations should there be? And what would be the most effective way to schedule the machining operations? The answers to such basic questions were far from clear.
But with the cubes costing £25,000 each, and storage racks more, guestimates could prove expensive if wrong. And insufficient storage space or poor scheduling could quickly transform a state of the art FMS installation into a productivitysapping bottleneck.
Virtual factories
Enter Witness, a shopfloor simulation system from simulation specialists Lanner Group. The Airbus project team electronically ‘built’ an FMS inside Witness and equipped it with varying configurations of cubes, storage racks and loading stations.
“Witness was able to rapidly calculate over a 12- hour shift how long each cube had been used for, the length of time that it was inside the machine, and then explore how this would work with over 115 different parts each with differing characteristics in their cycle times,” explains Airbus project leader Rui Furtado.
“Virtually running” the FMS with a wide variety of workloads, the project team was able to ensure that the FMS as finally installed was pre-configured for success — saving on costs, boosting productivity and achieving machine utilisation rates of between 80%-90%.
Increasingly manufacturing businesses are building such “virtual factories” in order to simulate the workings of complex machining operations, assembly processes, and logistics flows. The logic: trial-anderror inside a computer is a great deal cheaper, and quicker, than trial-and-error in the real world.
“We’re heading for our best year ever,” says Lanner’s chief executive, David Jones. Similar success stories, he adds, can be seen at Honda’s Swindon car plant, and at Nissan’s Sunderland plant, where simulation boosted the output of an assembly line producing the popular Qashqai model.
“The simulation of factory processes and logistics flows is increasingly widespread,” says Tom Bianchi, Simulia marketing manager at Dassault Systèmes, which offers such a capability through its Delmia ‘virtual factory’ process simulation tool. “Being able to optimise workflow and layout saves space and speeds process times, as well as ensuring that ‘as-built’ working environments allow people to work safely.”
CAD adds simulation
No wonder, perhaps, that analyst firm Gartner have listed simulation and optimisation software as one of their ‘Top 10’ strategic technologies for 2010. And little wonder too that a growing number of vendors are entering the market, offering a variety of pricepoints and levels of sophistication. Companies such as Simul8, ProModel and Visual8 all produce simulation solutions that have delivered benefits to blue-chip customers.
But ‘pure play’ simulation vendors are under threat: increasingly, CAD vendors are adding simulation capabilities to their products, recognising that product simulation — as opposed to process and layout simulation — is a bigger market. They see it is a market in which they already have a distinct advantage, as the platform on which a product design has already been digitally developed.
Staying with Dassault Systèmes, for instance, the Enovia data management product allows manufacturers to use the same digital data to both design a product in its 3D Catia tool and then take that data into its Simulia tool to look at the loads and stresses on as-designed components to see if they can withstand the rigours of their intended service life.
Then they model in detail the consequent assembly operations and the workings of the finished product.
“It’s about complex geometries where hand calculations are difficult to carry out,” says Geoff Haines, managing director of Oxfordshire-based Desktop Engineering, a Dassault reseller and business partner. “You can go to a much higher level of accuracy than you can with hand calculations, optimising the weight without the need for such a big ‘fudge factor’.” The result is products with improved manufacturability — and improved service life.
Autodesk, also a big player in the CAD market, is yet another vendor to have developed manufacturing simulation capabilities to augment its pure CAD product range.
“Through acquisition and organic development, we’ve now got a wide variety of simulation offerings,” says Richard Blatcher, the company’s European industry marketing manager. “We cover the spectrum from product performance simulation right through to the simulation of factory processes and assembly operations.” And in most of the engineering-intensive industries that the business serves, he notes, there’s a distinct trend for design engineers and manufacturing to work more closely together, increasing the push to use simulation at the design stage as a way of reducing bring-to-market timescales as well as boosting quality.
Autodesk’s Navisworks, for example, takes 3D CAD designs of components, products and even factory layouts, ‘building’ them to produce photorealistic visualisations for designers to optimise.
“Optimisation used to be expensive, and out of reach for small and medium-sized businesses,” Blatcher says. “Today’s generation of simulation software is more affordable and cost-effective than ever.” And with manufacturers’ product development cycles continuing to shrink, and their development budgets under more pressure than ever, that has to be good news.
