Analysis of a Flexible Small-Series Flow Line for Prototype Production of Cutting Inserts : A study carried out at Sandvik Coromant in Gimo in order to evaluate how a new flexibleflow line can be planned in order to meet requirements of short lead times andhigh service level

Abstract

In the modern manufacturing industry the need for faster and more robust product development processes is seen as one of the main strategic areas to focus on in order to support sustainable growth and even long term survival of companies due to continuously increasing global competition. For the metal-cutting tool manufacturer Sandvik Coromant product development is seen as a key strategic area and due to that improvements in the overall product development chain are being worked on. In order to have more reliable production of prototypes and at the same time have them delivered within short and predictable lead time a new small-series flexible manufacturing line needs to be set up. This project takes on analysis of three levels of analysis for this new manufacturing line, that is production planning, flow analysis and scenario analysis. Through the analysis information has been collected to set up the boundaries for which the system needs to work within, such as demand forecast, processing requirements and planning as well as estimation of cycle times for different steps in the flow. The project provider had already made a framework of manufacturing techniques and concepts which are known but the idea for this project was to put those pieces together in a system model which could be analysed with regards to flow characteristics and system performance. The results would then be a basis for a decision on capacity and layout design for the new system. It is shown that the decision on capacity is mostly related to resource planning at the system bottleneck, which is a precision material removal station applying either high-speed milling or laser technology for material removal. Scenarios for variables such as order batch sizes are analysed and it is shown how the target for service level can be reached by for example increasing lead time definition for large order batches. For a higher capacity option at the bottleneck operation the robustness of the system is tested by adjusting demand and cycle time needs for the bottleneck step, and this gives results within service level target for those scenarios. The idea is that all machining operations and key measurements for the products should be possible to do within the flow line. This results in relatively low utilization for some of the equipment, but this is a trade-off which makes the system flexible and independent. The effect of having a transportation robot for the flow line is checked as an alternative to having operator at the line 16 hours per day. In the base case with the operators, automatic pallet exchange functionality is set up at the two most utilized machines with local pallet magazine for parts to be manufactured. It is shown that a solution with a transportation robot would only result in about 1% higher serve level compared to the base case solution. It was a conclusion to recommend a solution with only one machine for the bottleneck operation and either add restriction on order batch sizes or define longer lead time for larger order batches. It was recommended to implement pallet exchanger with a local pallet magazine for pallets which hold the parts at two work stations which have the highest utilization. This solution would according to the given background information and input variables give a desired service level by operating with one operator 16 hours per day, 7 days a week, and unmanned night shifts for which the high utilization machines could be unloaded and loaded by an automated pallet exchanger and thus could operate automatically during night time