One line, every option

Photo | Bosch Rexroth AG
Marginal Column

Above: Joaquin F. Garcia talking with Gonzalo Parrado, who is responsible for the assembly line, and Rexroth sales engineer Jesús Abollado Fernández.

Ideal assembly conditions for products of varying sizes: Blusens puts its faith in a highly flexible assembly line.

The ergonomically correct workplaces keep needed tools within easy reach while the pallets offer protection against static build-up.

High-tech entertainment electronics – from diminutive MP3 players to large LED screens – are what Blusens Global Corporation manufactures on its new, automated line. And it has to be one thing above all: flexible.


At Blusens, located in Santiago de Compostela in Spain, the spirits are high. This manufacturer of modern entertainment electronics is recording growth rates of up to 200 percent per year. That’s because LCD and LED televisions are riding the crest of a wave and an end of this boom is not in sight. Blusens intends to keep up with the rapid development of the electronics industry. That is why it chose an assembly line built by Rexroth. This is where the company will be assembling television set, hard disk drives and MP3 players.

Simple modifications

Adaptability was right up at the top of the list of requirements. “We were looking for an assembly line that is flexible enough to handle many different products with differing dimensions,” notes Joaquin F. Garcia, customer service manager at Blusens. “And at Rexroth you can get everything from a single source,” he adds. Rexroth convinced decision makers with its automation solutions and the easily integrated components. The basis for the new manufacturing line is the TS 2plus conveyor system. The drive chains and pallets used here are electrically conductive. This protects sensitive electronic components against damage resulting from electrostatic discharge.

At Blusens the system forms a rectangle measuring about 1.5 by 16 meters, with ten positions on either side and thus a total of twenty workplaces. Lifting and traversing units move the pallets to the opposite side and similar units make sure they pallets are properly oriented as they reach the workplaces. The conveyor system is also equipped with an accumulator section for each workplace. There the pallets can be “parked” before assembly continues at the next station. Damped separators gently stop the pallets. Positioning units lift them a few millimeters, separating them from the conveyor chain. That eliminates any friction with the conveyor belt.

A perfect fit for large and small

Rexroth optimized the line to accommodate products of varying sizes, for flexible response to the broad product spectrum. This is where Blusens assembles MP3 and MP4 players, hard disk drives, and LED and LCD television sets with screens measuring 15 to 26 inches along the diagonal. If smaller products requiring only a few steps are being assembled, then the 640 × 640 millimeter pallets advance after a specified period of time.

When working on larger products that take more time, ongoing movement is triggered manually by the worker actuating a switch. The accumulator areas can also be disabled. Since no pallets are then parked there, there is more space between successive items. This keeps larger assemblies from colliding at adjacent workplaces. Individual stations can be shut down completely if assemblies do not have to pass through all the workplaces. This boosts the tempo and shortens production cycles. Individual functions can be selected at each workplace using an IndraLogic touch screen. Rexroth was responsible for programming and the electrical commissioning of this system.

Ergonomic and productive

Compressed air maintenance units supply perfectly conditioned air to guns used to blow away dust.


Manual production systems made by Rexroth offer the operator flexibility, good ergonomics and excellent accessibility to every tool, at every workplace. Compressed air maintenance units supply perfectly conditioned air to pistols used to dust off parts. Necessary accessories are served by electrical sockets and cables while balancers suspend power screwdrivers. This makes good ergonomic and economic sense: “With these improvements in ergonomics we can raise our productivity by about 25 percent, with the exact amount depending on the type of product,” Garcia explains. That dovetails with the company’s plans for expansion.

Ready for the next automation step

Subdividing the line into four zones makes for quick and easy modification to suit future assignments. This is also reflected in the electrical and mechanical layout of the transfer line. The control circuit for each zone is set up using a field bus module. Pneumatic valve manifolds attached to the field bus actuate the lifting, holding and positioning functions. Simple linkage using electrical I/O modules also adds flexibility since the individual zones can be reconfigured and rewired independent one from another. It will also be possible to automate manual workplaces by adding robots to achieve greater production capacities. Thus the engineers have already laid the groundwork for the next stage in automation.