Car manufacturer sees benefits via use of CC-Link open networks

Maruti Suzuki has been the largest single producer in the Indian car market for over 25 years, now contributing more than 1.5 million new vehicles annually. Operating out of manufacturing plants in Gurgaon and Manesar, the company produces 15 different brands and makes over 150 variants of its models. It is the first and only Indian company to have crossed the 10 million sales boundary, and exports widely around the world.

The Indian manufacturing plants are highly automated, yet are constantly being updated with new technologies and improved systems. In recent times it has installed several CC-Link industrial communications networks to enhance various systems on the shop floors, as part of a continuous development plan.

CC-Link is an open automation network technology that allows devices from many different manufacturers to be mixed and matched on the same network. This means users can install best-in-class control equipment, rather than being tied to a single manufacturer. Currently over 1200 products from more than 260 manufacturers are available.

CC-Link can be used to create networks that integrate digital I/O on the shop floor directly with enterprise IT systems so that stores, production, sales and distribution, finance and marketing all become one seamless operation. It is available in two different technology formats: a gigabit industrial Ethernet and a fieldbus.

Maruti Suzuki has already installed CC-Link in several applications, such as the Cordless Limit Wrench, a system which provides fool proofing for torquing of critical joints during the assembly of each vehicle. It guarantees application of correct torque by stopping the assembly conveyor if a joint is over- or under-torqued or even missed completely.

Reduced complexity

Previously the torque control system was hard wired and very complex: CC-Link has reduced the wiring and complexity by an order of magnitude, improving reliability and making maintenance far easier. It has also freed up shop floor space and reduced cost by enabling a much more compact control panel to be designed.

It has also been retrofitted to what Maruti-Suzuki calls the "Pika Pika' system. This is their interpretation of the "poke yoke' or error proofing system. The system guides the correct selection of component parts during assembly and prevents incorrect parts being used. With such a huge number of vehicle variations going down the line, without this kind of assistance it soon becomes difficult for assembly workers to always be sure they are fitting the right parts on the right vehicles. Hence CC-Link is playing a key role maintaining vehicle quality by ensuring errors are eliminated at source, preventing expensive re-work and making sure defects do not reach the customer. This is also one of the reasons why Maruti-Suzuki has been rated first by the prestigious JD Power survey for the last 12 years. In addition to these benefits, use of CC-Link in the Pika Pika system has provided cost reductions through simplified cabling, reduced installation time and increased flexibility when line changes or updates are implemented.

CC-Link was also used to update the Andon system and the Vehicle Tracking System (VTS). Andons (from the Japanese word for lantern) are typically large electronic displays used in manufacturing plants to communicate critical production information and faults to employees so that appropriate action can be taken. In the case of Maruti-Suzuki, the Andon system is used for monitoring, displaying and recording conveyor and equipment stoppage information and calculating line efficiency. The VTS system is critical for flexibility in manufacturing, and broadcasts individual vehicle information (model, chassis details, etc) to conveyor line equipment so that the correct parts are fitted and appropriate operations are executed at each work station. It also helps to increase line efficiency by eliminating the need for manual interventions.

Benefits gained within by the use of CC-Link in the VTS include a 40 per cent reduction in cables and hardware through use of CC-Link remote I/O, a reduction in installation time, capacity for transmitting up to 128 different signals and interconnectivity with other systems, Previously, the system had only allowed the handling of 4-5 signals and had no ability to communicate with other systems.

Quality control

All data captured by the VTS such as tightening torques, fluid levels and so on is logged for quality control and analysis within the enterprise IT system.

Maruti-Suzuki now has a range of expectations for the benefits CC-Link can deliver to the rest of the plant. They plan to increase the amount of data handled within the plant, and connect widely separated systems. These are both well within the capabilities of the network, whose 10Mbit communication speed allows dozens of stations to be updated in a few milliseconds. Further, with a single bus length of up to 1200m (13.2km with repeaters), CC-Link is also well suited to covering the large distances often encountered in automotive assembly plants. Finally, the plant management is expecting further cost savings in wiring and installation realised via the elimination of intermediate I/O and wiring by the use of devices such as nut-runners which connect directly to the network.

A final part of the system is local support. The CC-Link Partner Association (CLPA) recently opened an office in India, meaning that Maruti-Suzuki is looking forward to an ongoing CC-Link partnership, which may possibly include local manufacturing of CC-Link systems, along with ongoing training and support.

To find out more about CC-Link systems, please visit www.the-non-stop-open-network.com.