Identification and Monitoring  of Key Process Variables in a Tetra Brik Filling Machine

Ola Gunnarsson and Martin Karlsson

Centre for Mathematical Sciences
Mathematical Statistics
Lund Institute of Technology
Lund University
2000


Abstract:
There is today a lot of data available from the Tetra Brik Aseptic (TBA) filling machines through sensors and PLC systems. The idea is to try to use this information to correlate the quality related parameters with the quality of the output from the machine, i.e. the package. This master thesis is a general pre-study of how this data should be obtained, stored and used, and what could be the benefits.The work includes- Identification, through interviews with experts on the core competence areas, of which process variables are the most important for the output quality.- Evaluation of how the data should be used and presented to obtain the most valuable information. - Overview and evaluation of different logging and storage methods.Finally a prototype application is created using Wonderware's InSQL Server and Microsoft's SQL Server with a web interface. The application is a simple tool for tracing the conditions under which a package was produced. It is implemented and tested on the filling machine.An important result of the thesis is that it is not meaningful to rush into complex statistical calculations since the process is already well known. The emphasis should instead be put on troubleshooting and batch approval, i.e. certification that the process has taken place in accordance with the specifications.