Over the last decade the UK food processing industry has become increasing competitive. This leads the sector to maintain high numbers of product variations. Although some of these products are stable over long periods, others are short lived or seasonal. The ability to handle both the complexity of process and large variations in product format creates extreme difficulties in ensuring that the existing manufacturing, handling and packaging equipment has the process flexibility to cope. This paper presents an approach for investigating the performance envelopes of machines utilizing a constraint modelling environment. The approach aims to provide the engineer with enhanced understanding of the range of functionality of a given machine and provides the possibility of redesign to process variant product.