Simulation: the power of the digital factory

6 mins read

For companies that can afford it, systems that let you build virtual ‘digital factories’ can make the task of improving the way you move and make far more rewarding. Dean Palmer talks to manufacturers that have profited from the experience

There’s powerful software available today that’s capable of simulating everything in your factory – from 3D visualisation models of assembly lines to optimising your material flow, reducing your production bottlenecks or creating ‘virtual’ plant layouts directly from your CAD system. The only problems are which vendor to go with and making sure you get full buy-in from engineers within your four walls. For example, Fairchild Dornier, a manufacturer of short-haul aircraft based in Munich, Germany, improved its production throughput by a third on its 328JET aircraft using digital planning and simulation software from Tecnomatix Technologies. The company employs more than 4,000 people across its German and US sites, and in April 2001, the order book stood at $12 billion, so its big business. How did Dornier achieve such a huge improvement? Well, production itself needs to be very flexible: there’s a diversity of variants, strict quality and safety standards to adhere to, and every customer’s order is different. So build-to-order is crucial. And production scheduling at the Munich site has to cope with some 3,500 groups of parts from external suppliers, 2,500 in-house parts, 1,300 system components and 530 employees. With this huge mix of variables, simulation was clearly a starting point. So back in 1999, Dornier set up a dedicated digital planning, simulation and reconciliation unit with the express objective of trying to increase its production throughput and optimise the manufacturing process and plant layout. Three staff work here at present but the department is now set to expand. The team was given the initial task of re-engineering the 328JET’s assembly processes – which meant a feasibility study covering the entire assembly line, the paint shop and the flight readiness zone. The team would have to plan necessary investment and validate a simulation model and input data, as well as organise the changes required and harmonise the work involved. Since 1998, the company’s design engineering department had already been using Tecnomatix’s eM-Plant software to test new plant layouts. So in 1999, the new unit approached Tecnomatix and was given a trial version of eM-Workplace, Tecnomatix’s 3D visualisation software, to tackle its 328JET assembly issue. Teething problems, but... There were some initial problems. Yves Kemayou, Dornier’s assembly investigations engineer, explains: “There was a delay of a few months due to integration problems with our existing CAD system [Catia] and Metaphase PDM [SDRC’s product data management software]. All our existing design and equipment data was held in Catia, our 2D CAD design system.” Once this issue was solved though, the team was able, in just five days, to use a simplified 3D model in eM-Workplace to produce 3D visualisations of the hangar and the assembly process to enable the logistics and pre-assembly processes to be re-designed. The team also modeled and improved the manual manufacturing capability of the docks and assembly stations. For example, during the critical installation of the horizontal tail unit, re-design was necessary because it’s very difficult to reach. All 450 final assembly work instructions for the 328JET were used as the basis of simulating the production critical path networks. The team actually created a full reconciliation between all the work instructions within a single assembly sequence. This ensured that potential problems such as missing parts or a potential machine failure would be highlighted by future analyses based on the established models. The modifications formed the basis for new work planning in the factory. An in-house consultancy project produced a base model to illustrate the existing 328JET assembly line. For the first time, the company was able to model the entire assembly procedure for an aircraft, from pre-assembly stage to the final coat of paint and the flight readiness station. Materials flow simulation was carried out over the next four years with a capacity of 500,000 man-hours and materials for more than 200 aircraft. “I’d say we spent roughly £100k on purchasing the simulation software, plus some more on training and consultancy,” explains Kemayou. “But the real issue with simulating anything in a manufacturing environment is people on the shop floor. They’re simply not used to it. They want physical mock-ups, not digital.” He cites an example: “Last year, we had a problem on the 328JET ECS [environmental control system]. We told manufacturing engineering it wasn’t possible to assemble this unit in the aircraft due to a lack of space. It just wasn’t possible for a human to assemble. “Design engineering insisted on a physical mock-up so we spent two weeks creating one to prove the point. That was serious money wasted.” Clearly, there’s a place for simulation in every factory, but the culture and attitude of the engineers may delay the benefits until everyone is comfortable with working (and trusting) 3D visualisation and simulation data. Early visibility of costs The simulation software market seems to split into two areas. The first includes those vendors that have come from the 3D or CAD end of the market. The likes of UGS (which now owns EAI) and Delmia (part of Dassault Systemes). These can offer you the full range of simulation software but integrated into one suite (although the software is modular). The big advantage here, especially for the larger manufacturing companies, is that all their simulation needs can be wrapped up in one big suite of software, all nicely integrated and ‘talking’ to each other. But the price tag reflects this – £20,000 per seat or more. Vynce Paradise, director of product marketing at UGS and head of its new e-Factory software, explains the benefits of simulating real-world manufacturing events: “Companies traditionally don’t have any way of getting early visibility of manufacturing costs and process times. And it’s not easy for them to capture and re-use proven, best practice manufacturing processes. With simulation, you can these days.” And he goes on to say that many manufacturers often wait until production ramp-up time before testing new ideas or process layouts. “With e-Factory, we provide you with a platform for pre-production planning that gives you a managed environment for virtual manufacturing information with integrated tools for process planning and resource management.” The e-Factory suite is quite impressive. It includes a range of plug-ins covering every manufacturer’s needs: tool management; ergonomics and human safety; FactoryCAD (for plant layouts); FactoryAnalysis (for production planning, flow and optimisation); FactoryView (for creating virtual 3D factories); and a range of CAM and stamping products. UGS certainly has a very powerful suite of tools to offer, but as Paradise suggests, “e-Factory is initially being targeted at the medium to large size manufacturers.” Affordable to SMEs But what about SMEs (small to medium size enterprises) that simply don’t have tens of thousands of pounds to spend on simulation software? This brings us onto the second area - the simulation ‘specialists’. These tend to focus on simulating manufacturing flows, process planning, production throughput, logistics and some even integrated scheduling software. Companies like Tecnomatix, Lanner Group, Product Modelling Corporation (PMC) and Webb Systems are just four in this space. Webb Systems for example, a UK reseller of simulation software, has developed a product called ShowFlow. It’s essentially the same product as its more expensive predecessor, TaylorII (from Dutch software vendor InControl Simulations), but it’s been re-branded and treated to a bit of extra software development. It allows engineers to model and simulate their production processes and verify different designs of manufacturing systems. But its real advantage is its price – less than £300 for the software. “The biggest problem in the market these days is persuading the industrial or manufacturing engineer’s boss to part with his money. With ShowFlow we’ve deliberately made it affordable to SMEs so they don’t need sign off from above to purchase it,” explains Stephen Webb, md of Webb Systems. “But it’s still got all the functionality of its £10,000 predecessor.” Webb Systems started shipping ShowFlow in June this year and Webb says the company has already sold more copies since June than were sold in five years as TaylorII. So clearly there’s a market for more affordable simulation software, where companies cannot afford (or simply do not require) the same level of sophistication and functionality that big vendors like UGS and Delmia can offer. And customers in a wide variety of discrete industries are using ShowFlow: aerospace, automotive, pharmaceuticals, packaging, clothing, medical and confectionery. Even the likes of Nestle and Electrolux, neither of which could be classed as small vendors, are currently using it. “Five years ago the price band for simulation software was between £10k and £20k per seat. We see that band moving to those vendors who sell at less than £500, and those that sell above £20k,” predicts Webb. But Roger Randle, director of another mid-market vendor, PMC, has a different view: “We see the future for vendors all about being able to integrate with other enterprise systems like ERP, MRP, scheduling and CAD. To this end, we’ve just released our ‘Orchestrate’ product which has in-built scheduling functionality. Users can simulate manufacturing processes and flows through the factory, but can now also test out different scheduling rules and what-if scenarios.” PMC sells its manufacturing constraints-based simulation core software product, Pro-Model, to more than 500 UK-based discrete and process manufacturers such as British Bakeries, Siemens, JCB, Caterpillar and Jaguar Cars. The software costs around £12-15k, but Randle justifies this higher price by stating that, “With cheaper simulation software products, users will need to have people with specialist programming skills to create simulation models. With Pro-Model, we can get users fully trained and up and running in just a few days.” He also suggests there’s a trend amongst the smaller manufacturers to outsource their simulation requirements: “SMEs typically don’t have the in-house expertise to carry out simulation projects. Instead they outsource it to simulation vendors and consultants. This area of our business is growing.” It all works. Lanner Group’s Witness software is also helping companies save money. It helped Michelin’s tyre manufacturing plant in Dundee increase its production throughput of tyres by more than 12%, by improving product flow, streamlining the curing press lines and reducing the cycle time on the tyre-making process. “Witness was brilliant in enabling us to run a whole range of ‘what-if’ scenarios. We tested 30 different production options. It was quick too; we could simulate a whole day’s production in less than 20 minutes,” says Colin McIlraith, XM Services’ manufacturing systems consultant for the project.