- Created: 2018-08-06
Alfa Romeo’s new car, the Giulia, hits the road with the help of articulated robots
by Valeria Serpi, global solutions development, Comau
Car and Driver gives Alfa Romeo’s Giulia an impressive 4.5 out of 5 stars, calling it an “emotional, hot-blooded Italian sedan.” The 280-hp rear-wheel drive car has an unassuming look, but with an athletic chassis and a turbocharged engine built to please. To build this Italian masterpiece, Alfa Romeo needed to design a flexible, high-volume body-in-white (BIW) operation to meet the company’s aggressive production targets and time-to-market objectives.
From the outset, the Giulia was conceived to set new benchmarks in automotive design and manufacturing. The three models, Giulia, Giulia Super and Giulia Veloce, each have distinct features and performance specifications. These versions, together with the Giulia Quadrifoglio, the most powerful road-legal Alfa Romeo ever made, share the same lightweight architecture and are built on the same assembly line.
The line to construct the Giulia was installed within Alfa Romeo’s Cassino plant, but the automaker required a body platform solution that ensured the flexibility to enable future product alternatives. The project was defined, developed and deployed in record time.
Designed as a tribute to Alfa Romeo’s racing legacy, the groundbreaking and distinctive Italian design helped earn the Giulia top prize for Best Body Design at the 18th edition of the EuroCarBody competition.
Alfa Romeo requested that Comau, an Italian subsidiary of Fiat Chrysler Automobiles, spearhead the manufacturing strategy. Comau’s longstanding experience with the world’s most important OEMs and unique expertise in lightweight materials helped convince Alfa Romeo that the automation solution specialist was perfect for the job.
Another convincing factor was Comau’s unique co-engineering approach, especially given the extremely tight project timing and the need to build the new line within an existing ‘brownfield’ operation and its inherent floor plan constraints. Comau, therefore, became an integral part of a highly cooperative co-design team. The first task was to define the project requirements in terms of production, engineering and process manufacturing.
Comau was able to leverage its production-proven technical expertise to design and develop a complete solution based on the modular, flexible and expandable OpenGate framing system. This system guarantees high repeatability and can handle up to four different models for maximum flexibility and return on investment.
Details of a Comau welding machine, a pure combination of Comau robotic and welding gun technology.
Because its compact and lean architecture features up to 18 overhead-mounted robots and up to six dedicated model gates delivering high-speed, high-density operations, the Comau solution could facilitate the automated assembly of the Giulia while meeting Alfa Romeo’s production targets.
The Giulia line also used parts of Comau’s modular ComauFlex system, including the VersaRoll closed-loop assembly and joining system. VersaRoll is primarily used for setting the geometry of the body sides and the chassis, and assures the fast transfer of material through the line, which reduces non-value added time.
Comau solutions empower flexibility without any compromise to fixture quality.
In addition, both the OpenGate and VersaRoll systems utilize overhead-mounted robots, allowing the highest possible density of robots and increasing the volume of joining operations within each station.
Two of the elements that significantly contributed to the success of the project were the use of virtual simulation techniques and Comau’s World Class Manufacturing (WCM) approach.
Giovanni Di Stefano, the head of materials and process technologies at Comau, says that they are constantly focused on innovation. For example, the assembly solutions are “like a tailor-made suit, always compliant with the customer’s and product requirements.”
Unlike other Giulia models, the carbon-fiber roof of the Giulia Quadrifoglio is prepared and assembled within a 100 percent automated workstation.
Working closely with the Alfa Romeo team, Comau developed virtual test cells to evaluate the behavior of the materials and joining processes that would be used within a large-scale production environment. The team also performed physical testing to verify specific elements such as the bond quality of different joining techniques such as riveting and welding. Further tests were employed to establish which parameters were needed to optimize the manufacturing process, validate the geometry of the different assemblies and ensure the highest level of performance and vehicle quality.
The use of virtual cells also provided the team with an accurate, detailed simulation of the entire production line. By verifying the different processes in a virtual way, before the line was physically implemented, the companies were able to identify potential issues and improve the anticipated results.
In addition, virtual simulation was used to establish the estimated cycle times that Alfa Romeo could expect to achieve with the new line. These details were especially important given the need to accurately coordinate the movement and timing of numerous robots and their dressings with the multiple operations being performed.
Welding operations are more effective and precise because of Comau’s hollow wrist technology, granting full robot accessibility.
Di Stefano says that, as a rule, Comau uses simulation to verify different aspects of the manufacturing process, structural tests and algorithmic tests. As an example, “virtual commissioning” is a process whereby the industrial computer and robot are directed to program within a virtual environment before proceeding to site activities.
“This technique has been used ever since it was first used on Alfa Romeo Giulia’s project,” Di Stefano explains. “Comau has improved and intensified its practice on every project. Furthermore, it has been shown to improve the quality of not only the industrial computer and robot programs, but also the mechanical designs, documentation and electrical schemes.”
The first section of the line is where the chassis of the Alfa Romeo Giulia is built.
Zero to 60
The industrial scale of automaking is an impressive sight to see – especially during the first section of the Alfa Romeo manufacturing line when the Giulia’s chassis begins to take shape. It starts with the front framework where the engine and all of the related mechanical components are mounted and moved to the central floor, including the first row of seats and the back framework where the second row of seats are located.
Once the automatic cycle is started, each chassis is processed in sequence by a chorus of industrial robots. Once completed, the chassis moves on to the section of the line where the body is added. Here, a total of two OpenGate framing stations work sequentially in a unique configuration that allows Alfa Romeo to perform the delicate operation in a “double layer” construction process.
What this means is that the construction of the body is essentially broken down and assembled in two specific steps. In the first station, the structural or internal part of the chassis and its sides are built, while in the subsequent phase, the so-called ‘outer skin’ is added.
This advanced process greatly improves accessibility, helping facilitate the work of the robots as they weld, position the various elements and perform other activities that are needed to complete the assembly. Because the robots have complete, unobstructed access to the structural “skeleton” of the vehicle, welding operations are more effective and precise than in a traditional process, which leads to better overall manufacturing geometry.
Comau’s High Quality Dispensing Systems is one of the most important requirements for the Alfa Romeo brand.
Hit the roof
The extensive use of lightweight materials such as aluminum, which is inherently more delicate than its traditional steel-based counterparts, requires great precision and accuracy during the joining and finishing processes. And the Giulia Quadrifoglio model is fitted with a carbon-fiber roof and hood, further increasing the complexity of the process.
Unlike the other Giulia models, where the aluminum roof is fastened via laser brazing, the carbon-fiber roof of the Giulia Quadrifoglio is prepared and assembled within a 100 percent automated workstation. The patent-pending process consists of multiple robots that are aided by advanced vision and control systems to secure the highest possible standards.
Di Stefano says that beyond conventional process technologies, the Giulia delivers on a mix of high-performance materials and challenging yet innovative technologies. For example, the carbon roof assembly cell is a clear example of advanced technologies where there is an innovative robotized cleaning system, on-process vision system to assure bead quality and another vision system for fitting the roof to the body.
“There is also an infrared system for curing the adhesive once the joining geometry is achieved,” Di Stefano says. “A cutting-edge monitoring system keeps all the process parameters under control, and it’s mandatory.”
Comau’s OpenGate system can feature up to 18 overhead-mounted robots and up to six dedicated model gates.
Rolling the hem
Another innovative aspect of the manufacturing strategy is the use of advanced technologies, such as Comau’s Rhevo roller hemming system, which combines performance and efficiency with real-time data collection and process monitoring. With speeds of up to 750 mm per sec., Rhevo can hem very complex elements across multiple manufacturing lines while protecting the geometric uniformity of the assembled parts, reducing time-to-market and lowering overall production costs.
For the Giulia models, the Rhevo, short for Rolling Hemming Evolution, is used to hem the rear wheelarch, helping safeguard the rigid torque that the high-performance sports sedan requires. Here too, advanced vision systems are used to identify and correct any positioning variables introduced when the chassis is placed within the station.
Working in a pull mode, the Rhevo automatically hems the wheelarch, creating a perfectly precise drop hem in three passes while using two types of rollers. Once the hemming process is complete, the system automatically reconfigures itself for the next model.
While the scalability and versatility of Comau’s technology approach were fundamental in meeting Alfa Romeo’s strict requirements, the shared vision of what the two companies had to accomplish was even more important. Thanks to incredibly close teamwork and WCM processes, the groundbreaking project was rewarded with success on multiple levels.