The UK’s largest manufacturer of plasterboard and dry lining systems is using Quality Monitor Software from Northwest Analytical to implement consistent quality processes and improved productivity in plants throughout the UK.
Plasterboard is an unsung hero of the modern construction industry. By replacing wet plaster wall rendering with dry wall lining systems, builders reduce labour input and, as other work can continue as soon as the plasterboard is installed, they achieve valuable reductions in time on site.
It is no surprise, therefore, that plasterboard manufacturing is big business. British Gypsum is the UK’s largest plaster, plasterboard and related products manufacturer. The Company has been making plasterboard for over a century and today produces over 150million square metres every year in five plants across the UK.
Plasterboard is produced in an extrusion process. Plaster, water and various other additives are combined in a mechanical mixer and extruded between two layers of paper liner, before passing into a forming station which sets the width and thickness of the finished board. The board sets as it passes along the manufacturing line before passing into huge driers that drive off any remaining moisture in the board. It is then cut to length before being distributed to construction projects around the country.
Consistent quality is of critical importance to British Gypsum. Plasterboard products are manufactured to meet European standards which include strict dimensional tolerance limits. The Company also has its own internal quality standards, which help to maintain the excellent reputation of its products in the marketplace.
Quality is maintained at line side through a rigorous batch sampling process. Every three hours, a sample board is removed from the line to undergo a series of up to 40 different tests. These include overall dimensions, to suit the European standard, and a number of checks to meet internal quality standards including the occurrence of voids in the board and the quality of lining paper adhesion.
If a sample board fails any of the line side checks, a prescribed sequence of checks is completed on the rest of the boards in the batch. Boards that fail these secondary tests are recycled; those within tolerance are put back into the supply chain.
Until recently, the five different British Gypsum board-producing plants, while they all used the same quality checks, had different methods for recording the results. Most used paper-based recording systems of different types, while one had built its own in-house database system.
According to Amanda Nurcombe, Company quality systems manager at British Gypsum, a desire by the Company to introduce a standard process across all its plants, and to move away from the development and support of in-house software, led to a search for a better solution.
After evaluating various products, British Gypsum eventually settled on Northwest Analytical’s Quality Monitor package, supplied by Adept Scientific. NWA Quality Monitor is a powerful, dedicated solution for shop floor data collection and statistical process control. The package allows standardised workflow processes to be built to match the needs of a specific production line, stores data from multiple workstations in a central database and provides live charting and analysis of quality data.
British Gypsum worked with Adept Scientific to build a pilot Quality Monitor System at the Company’s Kirkby Thore plant in Cumbria. The ability to customise workflows was an important part of this pilot program, explains Amanda. “Different boards require different sets of tests. With the new system, the operator enters six digits from the manufacturing code that is printed on every board into the first screen of the system, then Quality Monitor pulls up a template with only the required tests on it.”
The Quality Monitor software also contains a comprehensive database of acceptable tolerances. As data is entered, the package gives instant feedback if a dimension is out of tolerance and tells the operator which secondary measurements should be carried out. Other optional screens give further support to operators, providing reminders of correct measurement protocols if required.
As well as providing live feedback on measurements, the Quality Monitor System also helps to enforce consistency in all checks. The system will not allow operators to pass a board until all measurements have been made and internal checks require data to be entered in a correct, consistent format.
While the line-side benefits of the Quality Monitor System are immediate, much of the power of the system comes into effect away from the production line. All collected data is linked live to a central database at British Gypsum’s HQ in East Leake, Leicestershire, while local caches keep data safe in the unlikely event of a network failure.
Production and quality engineers can access this data and use NWA’s Quality Analyst software to check ongoing performance, spot trends and search for the root cause of any problems. “Even during the pilot phase, I’ve been able to analyse data at my desk,” explains Amanda. “When we complete the roll-out to all the plants we will also be able to compare their performance on different products and share best practices between plants.”
When the pilot program at Kirkby Thore is complete in the spring, British Gypsum will roll out the Quality Monitor System to its other four plasterboard plants. The Company already has ambitious plans to move more responsibility for statistical process control to its line operators, making extensive use of the system’s live charting capabilities to deliver clear, graphical feedback to operators.
For Amanda, who is responsible for ensuring that British Gypsum continues to evolve and improve its quality processes, having a single, standard system in place will help greatly with control and flexibility. “With Quality Monitor I know that, as our requirements change in the future, the system is flexible enough for us to incorporate those changes directly into the database.”l