No matter how exotic the car, vehicles not using ‘wet’ clutches (automatic transmission) rely on a relatively thin layer of special material to interface engine power with the driven wheels – the clutch facing. In order to live up to Schaeffler’s exacting quality standards while meeting large demands, the production process of these facings at the company’s Port Elizabeth facility needed to be revised to incorporate the latest batch mixing and tracking technologies in a difficult manufacturing environment.
Project requirements
The business objectives called for an automated warehouse inventory control system, a batch tracking system and a reporting facility. Material would be picked according to its expiry date while provision would have to be made for stock levels and the location of all stock had to be readily available to qualified personnel. The batch tracking system would need to track raw material batch numbers through to final product and vice versa. There was also a need to interface to a laboratory testing facility.
While the need for reliable operation goes without saying in a real-time production environment, the conditions at the plant proved to be somewhat challenging with an atmosphere thick with carbon black. To overcome this, a simple and robust operator interface was required as the standard keyboard/mouse combination had proved useless and even touch panels were prone to failure.
Solution selection
Both the hardware and software needed upgrading and a fresh approach was necessary. “Since the existing scada facility was based on Wonderware’s InTouch and InTrack (MES) solutions which had served the company well since 1997, it made sense to continue using products from the Wonderware stable,” says Barry Clemence, software engineer at DC Industrial Scanning, the system integrator chosen for the previous installation and this upgrade in order to minimise risk. So DC Industrial Scanning chose the Wonderware System Platform based on ArchestrA technology as well as the Wonderware Information Server.
Solution architecture
The system topology utilises a three-button operator interface and handheld wireless computer. The buttons allow for easy navigation between screens, function selection, SQL grid selection and executing the stepping sequence while being easily replaceable at very low cost. The mouse and keyboard are now only used for administrator functions. “The buttons are connected to a standard serial port and a .NET object was written inside ArchestrA to do the interfacing,” says Clemence. “The result is a robust unit made from readily-available components.”
The handheld wireless computer is used to guide the operators via screen prompts while allowing them to scan barcodes or key in information on the move throughout the plant. This was also integrated directly into ArchestrA with another .NET object.
The new ArchestrA SQL object provided a reliable way to interface to the SQL database. The new SQL Grid proved to be very flexible and was a great way to display database information. “One place we used the grid was to display the various recipes thereby enabling the operator to select and start the required recipe using the button interface,” adds Clemence.
The ArchestrA system is interfaced with Oracle to retrieve the information for the material received and the system had to be developed, tested and implemented live. “We did dry runs where possible,” says Clemence, “but with implementation came the normal teething issues and specification changes.”
Realised benefits
* Automated process – the level of automation and checks and balances incorporated into the system has greatly reduced operator error while providing the necessary guidance for optimal smooth running processes.
* Accurate warehouse management system – this now provides current stock levels immediately on request and knows where each bag of material is stored and how much is left. This has led to less material loss due to material expiry.
* Easier, more reliable operation – wireless scanner and screen prompts as well as the robust button user interface allow operators to do a better job.
* Mixing benefits – strict recipe management now prevents the wrong materials being added to the mixture or added in the wrong amounts which all contributes to reducing scrap.
* Traceability – it is now possible to trace raw material batch numbers from the suppliers to the end product and vice versa.
* Reports – using the company’s intranet, reports such as stock levels, batch tracking, raw material tracking, batch details (eg, weights per material) and exception errors such as process problems can be viewed. The back end is powered using a combination of Microsoft SQL Reporting Services and Wonderware Reporting Services.
* Computer failure recovery – it is now easy to recover from a computer failure whereas this was not previously possible.
For more information contact Deon van Aardt, Wonderware Southern Africa, 0861 WONDER, [email protected], www.wonderware.co.za
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