With over half a billion cars in daily use worldwide, emission control is no longer an option. Tenneco is a world leader in this technology and was one of the first suppliers to commercialise the diesel particulate filter (DPF) technology that is 99,9% effective in eliminating emissions from diesel-powered vehicles.
As the need for catalytic converters grows, so does the necessity to streamline their manufacture. The cycle time for a single converter currently stands at 27 seconds, which does not leave much room for getting things wrong.
Automotive components - the global approach with local manufacturing
With South Africa having opened its borders to free trade agreements, the country has become part of the global community and as such, SA manufacturers have to compete locally against imports and internationally against domestic manufacturing in other countries (Tenneco SA exports to the USA, Europe and Australia). But with detailed and product-specific information, companies are better equipped to develop strategies for efficient growth.
To be cost-effective and efficient, more and more companies are utilising software not only to monitor the plant and to provide diagnostic information but they also use realtime databases to identify each product and trace it through the entire manufacturing process. Decision-support information has therefore become product- and process-specific with the focus on quality, efficiency and production availability. The ability to access databases in realtime and view scheduled reports provides for an environment where constant improvement is feasible and cost effectiveness per product is increased.
Customer requirements
In order to achieve its business objectives, Tenneco SA realised that the company would need to upgrade its existing scada facilities in a way that would consolidate existing assets while providing for the future and addressing pressing needs such as:
* Cost saving and standardisation.
* Part traceability and tracking.
* Process control and security.
* A single platform to control the entire plant.
* Simplification of architecture, layouts and technical support.
* Complete database integrity and access.
* Full server redundancy.
* Reporting and diagnostics.
* Assurance of technical and quality standards.
* Full access to various existing databases.
* Full visual system with realtime plant-wide reporting including data analysis techniques.
The first phase of this upgrade initiative would be on a production line supplying North America and which manufactures 500 000 converters annually for export. The line operates on three shifts, five days a week. One of the goals was for this line to have a Cpk index of 1,33 or greater (Cpk is a process capability index. A process must have a Cpk value of 1 or more. The greater this value above 1, the more stable the process and the less deviation will be experienced.)
The line consists of several stations, which must assemble the converters such that the correct monolith (the active material that neutralises emissions) is inserted into the correct case. All the various parts involved in this process can be mixed up and have to be tracked from beginning to end in a manufacturing cycle time that lasts less than half a minute.
Solution selection
Tenneco SA selected system integrator Design South Africa for the implementation of the North American project. Design SA is a global company specialising in automotive and full engineering solutions. The company operates in Europe, North America, Australia, Asia and in South Africa. Design SA has branches in Port Elizabeth, Durban and Johannesburg.
Design SA selected Wonderware solutions because the existing facilities used InTouch HMI (human-machine interfaces) applications and because the ArchestrA architecture would provide a single integrating platform for these islands of data and the ability to define, deploy and maintain the standard automation objects Tenneco SA was looking for. ArchestrA would also fulfil the requirement for full redundancy and provide the necessary functionality for the efficient deployment of software upgrades from a central location. Wonderware's Production Event Module (PEM) would provide the necessary advanced functionality for material tracking and traceability and the realtime database would be Wonderware's IndustrialSQL Server. An InTouch view client was also added. A key deciding factor in the selection of solutions was the professional local support available from Futuristix, sole SA distributor for the Wonderware range of industrial automation and MES solutions and a member of the EOH group of companies.
Project implementation
Figure 1 shows the topology of the production line with the dual-redundant ArchestrA Application Object Servers (AOS), the InSQL database, the various stations of the converter assembly process as well as the fixed and handheld scanners used for part identification.
Each station will consume material supplied by other stations and produce material that will be consumed by them until the final product is completed. The PEM is an object running on the AOS, which forms part of each station and that keeps track of these 'consumed' and 'produced' items at each stage of the production process. All the PEM consumed and produced data is stored in the InSQL database with the result that the process can be 'rewound' to analyse the assembly sequence of the components that make up the finished product. The PEM stores the information in ISA-95 format, a database standard that allows for easier data integration of control systems with other enterprise applications.
"In the event that the database should become unavailable, the PEM allows for data queuing on the AOS," says Donovan Bradley, operations director for Design SA. "Once the link has been restored, the data is sent to InSQL. If the database becomes unavailable, however, it is not possible to read data from the queue for assembly purposes. In order to maintain production in the absence of the database, we developed a work in progress (WIP) array using scripting. This array resides on the AOS and is capable of storing up to 1000 parts per station. When the database becomes available, the PEM restores the data without any loss. As the work is successfully completed at a station, the WIP in a previous station is deleted and passed on to the next. When any WIP is updated, the PEM stores the information in InSQL."
Each converter model on the production line has different setup values that need to be monitored during the production process. These variables are created, updated and stored using a Recipe Manager. This approach greatly simplifies the introduction of new models or changing specifications on current models.
"Currently under development is the reporting of production values to operators and to management alike," adds Bradley. "We will also be installing Wonderware's SuiteVoyager web portal and this will be greatly simplified since the PEM has already ensured that the database is in ISA-95 format. Also on the agenda for the near future is the connection to other databases such as those used by Tenneco's suppliers."
Derived benefits and goals achieved
* Significant cost savings - it is estimated that, through the use of the ArchestrA platform, a saving of 25% of the automation implementation cost per production line can be realised in the future. This is mainly due to reduced software development and maintenance costs as well as reduced hardware costs through the rationalisation of resources.
* Easy database access - all data is available on the management workstation thereby eliminating the need to visit each individual workstation.
* Maintenance of quality standards - the new system facilitates the Six Sigma approach to quality, which has been adopted worldwide by Tenneco.
* Process security and process tracking - effective part quality control and identification during production as well as the tracking of the individual components that make up the finished product.
* Product genealogy - all the data for each product is detailed and recorded throughout the process.
* Improved control and management information - plant efficiencies and production availability were given detailed analysis options.
* Improved line availability - callouts have been minimised, the response time to deal with problems has been reduced, downtime is lower, and faultfinding is simpler and faster because of operator diagnostics that support first-level corrective action.
* Improved alarming, maintenance reporting and scheduling.
"This project is a good example of how quality and efficiency can be improved in a competitive market by using off-the-shelf software that conforms to international standards and that has been designed to protect ROI," concludes Bradley.
For more information contact Justin Tweedie, Wonderware Africa (a member of the EOH Group of Companies), +27 (0) 861 WONDER (+27 (0) 861 966 337), [email protected] or [email protected]
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