The reduced number of type changes resulted in savings in glass production. (ref: case Lahden lasitehdas)
Project title
The reduced number of type changes resulted in savings in glass production. (ref: case Lahden lasitehdas)
User company name
Lahden lasitehdas
Industry sector
Building Materials
Production process type
Glass production, FLOAT-method
Application area
Production Optimisation
Employees
50-250
Year the project started
1995
Supplier of service
HUT System analysis laboratory; University of Jyväskylä, Laboratory of scientific computing. Link to supplier: http://www.sal.hut.fi/, http://www.mit.jyu.fi/tutkimus/lsc/
Pay-back time in months
N/A
Type of simulation used
Scheduling
Short description of the project
Lahden Lasitehdas (sales 160 Million Finnish mark in 1993) uses FLOAT-method to produce glass. This means that molten glass is drawn over the molten tin bath cooling down slowly. When producing glasses with various thicknesses with change-over times being long, the production must be planned catering for orders and sales forecast. If the demand is known, it is possible to reduce amount of glass type changes from 8 per month to 6 or even 4 per month. The production is modelled using MIP (mixed integer programming) and the problems are solved using LP2-software which is developed using Branch&Bound -technologies. (Reference: Lahdelma, R., Ruuth, S., Kuosmanen, H. and Pennanen, T., lasitehtaan tuotannon optimointi ja sen taloudelliset vaikutukset, Proceedings of Automaatio 1995, Helsinki 1995.)
Soft Benefits
The delivery reliability, punctuality and flexibility of the production are likely to be improved.
Public quantitative benefits
The savings resulted in the reduce of glass type changes from 8 per month to 6 per month are estimated to be about 1 million Finnish mark.
