New materials and the drive for greater flexibility in production have created new challenges in handling

Walk through almost any modern automotive assembly plant and the major trends in automotive assembly aren’t difficult to spot. Equally clear to see are the tensions and trade-offs that exist between them. The inexorable march of automation, for instance, drives productivity upwards and unit vehicle costs downwards, but in plants striving for flexibility and mixed-model manufacture, ill-considered automation imposes constraints that make such objectives more difficult to attain.

 Similarly, the push towards lightweighting sees manufacturers adopting newer, lighter materials. The downside being that, more easily damaged, such materials require careful handling which can drive up equipment costs while acting as a drag on cycle time reduction.

Improved capability

Talk to the companies which serve as the automotive industry’s equipment suppliers and these tensions and trade-offs are evident. At the forefront of designing, building and delivering the machinery which turns aspiration into factory floor reality, they typically supply the equipment that actually touches the vehicle or its major components; gripping systems, robots, conveyor systems, and automation and control systems.

“All the automotive OEMs are demanding greater capabilities from the equipment they buy – faster cycle times, faster set-up times, higher throughput, greater flexibility and shorter delivery times,” says Martin Sahlman, product manager for automation systems at press and automation specialist AP&T. “For us, that means modular construction, fewer components and a requirement to produce and deliver the equipment quickly.”

Suppliers engaged in materials handling are tasked with quickly and efficiently bringing parts together at the applicable station in the shortest possible cycle time, then just as efficiently moving them on to the next stage in the assembly process.

So what trends are automotive materials handling companies seeing, and how are they responding?

Lightweight trend

As materials handling insiders make clear, the industry’s longstanding drive for improved productivity and lightweighting is still throwing up new twists.

Craig Kenhart, industry segment manager for automotive belting system manufacturer Habasit, for instance, points to the enhanced use of ‘people-mover’ conveyors in assembly plants, allowing workers to travel with vehicles as they are being assembled. Such systems, notes Kenhart, have been shown to increase productivity, reduce worker injury and decrease rework. [sam_ad id=17 codes='true']

Forget people-movers constructed from traditional heavy rubber conveyor belts containing steel cord members, he stresses. Today, it is modular or fabric-based people mover belts that are finding favour. Pointing to advantages such as low energy consumption, due to the low coefficient friction of the reverse side; a belt-edge ‘safety signal’ (belt edges can be equipped with yellow coloured modules); and non-slip belt surface profiles, Kenhart says that Habasit works closely with automotive OEMs and conveyors systems suppliers to advance what is possible.

“Belting to address the different load levels that can be found with people-movers is available, as well as belts with specific material features such as anti-static, electrically conductive and flame retardant,” adds Kenhart. “We’re seeing increased demand for people-mover installations in the traditional automotive production locations, as well as in the growing markets of China, Russia, South East Asia and South America.”

Lightweighting, too, is throwing up new considerations. As well as the materials traditionally used as steel substitutes – plastics and plastic-based composites – aluminium is finding favour, says AP&T’s Sahlman. “While lighter than steel, it’s a lot softer, which has a bigger impact on the associated material handling equipment,” he points out. “Not only does that mean you have to have handling equipment that doesn’t cause scratches, it also means that you need a cleaner, more hygienic environment, avoiding production debris.”

Focus on flexibility

Even so, the big story is flexibility, with automotive OEMs replacing single-model factories with assembly plants which can handle multiple models, changing the mix of production based on sales and customer demand.

Moreover, ambitions are high. Ford, for instance, has not only moved the majority of its plants to multi-model manufacture, but has stretched the envelope of what multimodel can encompass. Its Flat Rock, Michigan plant has recently been re-tooled for the 2013 Ford Fusion mid-sized sedan alongside Ford Mustang production – two models which could hardly be more different.

“The overarching trend in automotive assembly is the flexibilisation of assembly lines, which calls for equal flexibilisation of the associated materials handling technology,” says Werner Reichelt, head of the automotive industry segment at gripping, clamping and drive specialist Festo. “We’re seeing other requirements – such as advances in energy efficiency and safety technology – but flexibilisation is the major one.”

Todd Montpass, market development manager for the automotive and tyre industries at Rockwell Automation, agrees. “The drive for flexible manufacturing is probably the biggest trend in the industry right now: building multiple models in plants that might not have done that before,” he says. “It’s driving a lot of process change in vehicle assembly plants, as well as posing space utilisation challenges. It’s one thing being multi-model, and quite another being multimodel within the same footprint.”

The same picture is seen at vacuum handling specialist J. Schmalz, adds Jochen Gunkel, head of the company’s automotive industry group. “German and Japanese manufacturers are concentrating on creating flexible platforms on which they can build as many vehicle models as possible,” he notes. “For us, that means developing flexible and universal gripping systems, capable of delivering parts at a high rate of production, and with suction cups that can grip even at high rates of speed and acceleration.”

Multi-model lines

At Festo, meanwhile, the push for flexibility has seen the business move out of its core niche as a pneumatics supplier. “Originally, we were a pneumatics supplier, but increasingly we have moved into electro-mechanical devices and actuators, as well as a turnkey design and build service,” says Reichelt. “This helps our automotive partners and automotive machinery manufacturers achieve their flexibilisation goals, and produce more vehicles on the same line.”

For every pneumatic cylinder in Festo’s range, he explains, today there is almost always an electro-mechanical direct equivalent, driven by a servo motor. “If you need very, very precise positioning, it’s difficult to achieve that with pneumatics – compressed air has an element of ‘springiness’ to it,” explains Reichelt. “For real precision, you have pneumatics on the Z-axis, because it’s lighter and cheaper, and electro-server electro-mechanical devices on the X- and Y-axes, where you need the precision, in order to precisely grip the parts in question. In other words, you need both technologies to get an efficient, flexible solution.”

The automotive industry is recognising this, Reichelt adds. Already specified as the standard sole supplier at BMW, and the predominant supplier at Daimler, Festo is seeing other automotive OEMs’ pushes into flexible multi-model manufacturing play to its strengths. 

“We’re growing our market share at Ford and GM, where our capabilities have now been added to these manufacturers’ internal engineering specifications,” says Reichelt. “Traditionally, the engineers specifying pneumatics have been different from the engineers specifying electromechanical equipment – now they are coming together, which helps us.”

A similar message comes from overhead conveyor system specialist OCS Overhead Conveyor Systems, with the drive for multi-model flexibility making itself felt in demand for a new generation of overhead carriers, says area sales manager Jan Erik Karlsson.

“The goal is not only to develop a product carrier to deliver the best ergonomic solution, but also enable customers to get as many functions as possible in the same carrier,” he says. “This avoids bottlenecks in the assembly line and means that the product can stay in the same carrier from the start position through kitting, assembly and testing, and will finally reach the unloading point at an exact and controlled cycle.”

Long-term view

That said, while the push for multi-model flexibility is the overarching trend, materials handling suppliers are also seeing a similar demand for flexibility in how they actually deliver the solutions that they offer in response.

“Automotive OEMs have moved from a payback mindset seen in terms of individual projects, to a longer-term view of their requirements, and acquiring functionality which they will be able to use over that longer term,” says AP&T’s Sahlman.

Rockwell’s Montpass concurs, highlighting a shift in both the size of equipment and the underlying philosophy of equipment control. “Instead of one big controller controlling multiple stations, automotive OEMs want distributed control and smaller and more flexible controllers,” he notes. “This gives them the flexibility to move work around, and re-balance the line dynamically.”

From a software perspective, too, he adds, there’s a much tighter integration between the plant floor manufacturing execution system, the business system and the individual controllers. “Automation used to be: ‘Am I building a sun roof, or am I not building a sun roof?’,” he says. “Now, the software has to be far more flexible, and capable of handling more functions.”

Back at Schmalz, Gunkel doesn’t hesitate to point out the reliability implications of equipment that is more complex as well as smaller, more distributed and more flexible than previous generations – as well as capable of producing at higher output levels. “For us, that means adding predictive maintenance and condition-monitoring technologies to our existing vacuum pump and vacuum handling solutions, which means that the product includes more electronics,” he explains.

Gunkel continues: “The idea is to be able to predict failure that would cause downtime, and alert the operator in advance – and to do so, what’s more, without requiring the operator to enter the robotic cell – doing it through SCADA and PLC systems.”

In short, the requirements in automotive assembly are changing rapidly, and the good news for manufacturers is that so too is the materials handling industry which is supporting that change.