Combining Yield Optimization Of Material Packs With High Machine Utilisation
The SECANT cutting optimization engine is frequently called upon to help in creating solutions for unusual one-off applications. Whether it is integrating cutting optimization into a automated panel production factory with a massive twenty metre long saw bed or providing a web based cost estimating facility for two hundred plus salesman in the metal industry we are always willing to develop new variants of our engine to meet special requirements.
A recent example occurred when PSL was approached by Mr Mike Ramsey, Managing Director of the Ramsey Timber Group. The Ramsey Timber Group are suppliers of moulded timber components to the bedding industry. Mr Ramsey was looking to streamline production and had identified the critical elements as the efficient cutting of the raw material whilst sustaining the highest levels of utilisation of an expensive moulding plant.
The requirements for the new cut planning software were:
- To integrate with a new order and stock management system.
- To cut plan entire packs of raw material. The costs of handling and storing partial cut packs being prohibitive.
- To ensure that the moulding machine downstream from the saw bed was running at full capacity whenever possible.
- To achieve the above while maintaining low material wastage levels.
The SECANT application already offered a range of interfaces to integrate with order taking and stock management systems. In this case a simple comma separated ASCII file interface was chosen.
The most important factor in keeping the moulder fully utilised was to minimise changes in the type of order being processed. Each change of order resulted in non-productive downtime while the machine was reset. Conflict between this requirement and that of waste minimisation is to be expected as the highest yields are frequently only achieved through combining several orders in the cutting pattern.
Achieving a balance between the objective of low wastage on the one hand and the benefits of pattern simplicity on the other is a common requirement. The same broad issue occurs when cut pieces need to be taken away from the saw on a limited number of conveyor belts (feedlines). In this case it proved possible to modify the existing feedline model to ensure that once production of an order was begun, sufficient of that order was produced in each subsequent pattern to allow the entire order to pass through the moulder without interruption in production. This restriction naturally increased wastage levels however it was found that by a judicious selection of the sequence in which orders were produced this increase could be substantially reduced.
The second development was more fundamental. When selecting a new pack of material from stock for cut planning the optimizer must take into account the restriction that all of the pack must be used. An efficient cutting pattern for one board of material is of no consequence if the remaining boards in the pack cannot also be cut efficiently.
The central component of the SECANT engine is the pattern generator. This component was developed so that in stead of single patterns, blocks of patterns were produced representing the processing of full packs of raw material. Patterns were only accepted on the basis of the efficiency of the complete block.
The specially tailored system was delivered within six months of the receipt of an agreement to proceed. SECANT was able to rise to the challenge of sustaining high material yields whilst meeting the critical work flow targets of the client.
Mike Ramsey commented “PSL worked closely with us to tailor their product to our special situation. The result is a system that addresses our needs, improves yields, and gives us consistent and reliable control over our costs”.