Lotus Cars Ltd. has been famous for cutting-edge technology for more than 60 years. For decades, the British company founded by legendary engineer Colin Chapman was synonymous with Formula 1 motor racing.
During the 1960s and 1970s, sleek Lotus race cars piloted by an all-star lineup of drivers such as Jimmy Clark, Graham Hill, Jochen Rindt, Emerson Fittipaldi and Mario Andretti dominated the racing world. Along the way, the company pioneered things such as aerodynamic wings, ground effects and lightweight materials.
Lotus also dabbled with road cars as a way to support its racing team (a concept it borrowed from archrival Ferrari). In recent years, however, the company has focused its attention on high-performance sports cars.
The low-volume automaker recently announced that it plans to launch a new family of electric vehicles that will feature cutting-edge lightweight chassis technology. However, while EVs are the future, Lotus engineers aren’t ready to give up on the internal combustion engine (ICE) just yet. In fact, they’re gearing up for one last hurrah in the ICE era with the new Emira, a mid-engine model due to go into production early next year.
“The Emira is a game-changer for [us],” says Matt Windle, managing director of Lotus Cars. “It stands as a beacon of everything we have achieved to date in the transformation of the business, the embodiment of our progress. It is a highly significant milestone on our path to becoming a truly global performance car brand.
“The Emira has been developed on a new lightweight bonded aluminum chassis, technology pioneered by Lotus and which remains an intrinsic part of the company’s sports car DNA,” explains Windle.
The built-to-order Emira will be the first all-new Lotus sports car to be delivered under Vision80, a strategic plan that is guiding the transformation of Lotus as it moves toward its 80th anniversary in 2028.
New Production Philosophy
To produce the Emira, Lotus recently retooled its flagship factory in Hethel, which is located 110 miles northeast of London. It installed automated guided vehicles (AGVs), robots and other state-of-the-art automation to improve productivity and flexibility. The entire production facility is also powered by 100 percent renewable electricity.
“By the end of the year, [our entire] sports car manufacturing facilities and processes will be either new or vastly improved,” says David Hewitt, executive director of operations at Lotus Cars. “This will give us solid foundations to maintain our leadership in the rapidly changing low-volume automotive assembly industry.
“The move to a part-robotized production [system] is the right one for Lotus, as we launch the Emira,” notes Hewitt. “Everything is about repeatability and efficiency to drive quality. Our workforce is incredibly skilled, and robots [will] help them deliver the consistency we need at the volume we need.
“Our cars will remain ‘Handmade in Hethel,’ though our people will be supported by new processes and technologies that will only enhance efficiency and build quality,” Hewitt points out. “It is a best of both worlds solution.”
To automate its factory, Lotus turned to the Dürr Group, which offers an open, modular approach to automobile production. Dürr calls this strategy NEXT.assembly. It integrates all of the company’s technology into a one-stop system aimed at enabling manufacturers to assemble vehicles as efficiently as possible.
“Car manufacturers are rethinking traditional production line concepts,” says Darren Ashmore, managing director of Dürr Ltd. “They are constantly striving for higher efficiency, more flexibility and a reduction in the number of production stops, while keeping production losses to a minimum.
“Large scale, rigid production lines requiring significant amounts of expensive conveyor systems do not give the flexibility or scalability required by many manufacturers today,” claims Ashmore. “In particular, low-volume manufacturers are often looking for solutions that enable them to easily scale up production as they grow.
“The Lotus assembly process is generally more manual, with longer cycle times than [typically seen in high-volume production applications, such as pickup trucks or sport utility vehicles],” explains Ashmore. “Lotus sports cars are made of composite materials that require bonding, as opposed to traditional welding techniques.
“The Lotus layout is similar to other low-volume facilities, but is typically on a smaller scale, with only one model being processed in a loop configuration with less process stations,” says Ashore. “Use of AGVs with variable height capability enables different build processes to be undertaken within one workstation. It also means that production process changes can be relatively easily implemented to facilitate the launch of new models.”
Lotus did not use any AGVs in the past. In fact, the previous assembly line did not have any process conveyors and was based on a trolley with manual index.
“Lotus originally requested a transportation system utilizing an overhead electrified monorail system,” Ashmore points out. “But, following internal discussions, that requirement was changed to AGVs to give them more flexibility. For example, the conveyors enable Lotus to easily take car bodies to other offline processes, such as measurement, test and inspection.”
State-of-the-Art Equipment
Emira production begins at Lotus Advanced Structures, an all-new facility in nearby Norwich where chassis fabrication and front-end assembly takes place.
“By bringing the aluminum chassis and steel subassembly manufacturing businesses together into one facility, we can further improve upon efficiencies and productivity,” says Hewitt. In addition to fabricating subframes, the Norwich plant produces suspension components and other key parts for Lotus cars.
The Hethel factory houses a body shop, paint shop and final assembly line. It features a new semiautomated body assembly system, with robots being used to apply adhesive.
"The framing line is building car bodies, with robots applying bonding agent to the sides, roof and cantrails,” explains Hewitt.
Lotus has also installed robots in its paint shop to improve quality, capacity and process repeatability. The main priority was extremely high process efficiency while maintaining the high quality associated with the old manual spraying process. Other features include a combined primer and clearcoat line that is energy-efficient and reduces paint usage.
Four Dürr EcoRP E133 six-axis robots are flexible enough to enable a number of painting applications. With the composite body panels coated with conductive primer, one pair of robots process the application of primer and clear coat in one mixed spray booth while a second pair of robots apply the color coat in another booth.
Another big change inside the 55-year-old Hethel factory is the use of AGVs on the main assembly line.
“AGVs allow for the highly efficient movement of cars in build on set routes around the factory, allowing [operators] to focus on assembling the vehicles,” says Ashmore. “Routes are easily reprogrammed, creating a flexible and future-proof approach to Lotus sports car manufacturing.
“Compared to traditional conveyors, ergonomics is one of the major benefits of an assembly line with AGVs,” claims Ashmore. “Each [device] has an adjustable electrohydraulic lift table so operators can position a car at exactly the right ergonomic height.
“The vehicle becomes totally and easily accessible, from every [location],” adds Ashmore. “The limited height of the AGV, as well as the presence of a lifting table, make the vehicle easily accessible, even for trim operations inside the cabin and below the body.”
The Hethel plant uses 34 ProFleet AGVs developed by Dürr’s Italian subsidiary, CPM. They are equipped with natural navigation, which enables engineers to change paths and production layouts without significant impact.
The AGVs are used for trim and final assembly operations. They are provided with bidirectional kinematics and controlled by an in-house fleet management system based on an open software architecture.
The AGVs load car bodies at the beginning of the Emira assembly line and transport them through the entire assembly line in stop-and-go mode. Each AGV stops at a workstation for the time required to perform the necessary operations and then continues to the end of line where tests and quality checks are performed.
“AGVs are the perfect transport system for medium-sized production outputs, such as those at Lotus,” says Ashmore. “The use of AGVs in assembly shops guarantees a very high degree of flexibility.
“Choosing a fleet of AGVs over traditional conveyors allows automakers like Lotus to switch from a monumental and rigid system to a fully agile one,” explains Ashmore. “A fleet of AGVs also represents a scalable system that can be implemented over time. A limited initial investment can be increased at a later date and adapted to the actual production conditions over time.”
The retooled Hethel factory also uses Dürr equipment for end-of-line testing. Machines measure things such as advanced driver assistance systems (ADAS), brakes, headlamps and wheel alignment.
“The wheel alignment stand is designed for automatic measurement of toe, camber and caster, and manual setting of vehicle axle geometry (toe and caster) at the end of the production line,” says Ashmore.
The test stand is designed to perform the following tasks:
- Multiple point measurement during rotation of wheels with noncontact digital laser measurement technology.
- Automatic wheelbase adjustment.
- Automatic vehicle positioning.
- Manual setting of axle geometry with stationary wheels.
The ADAS system handles the calibration of the forward-looking camera and front-radar module in a self-calibration routine by presenting different targets and patterns in front of the respective module. Various dynamic driving conditions are simulated under road-like conditions.
