Identifiering av flaskhalsar och optimering av produktionsflöde för fixkapade rör

Sammanfattning

For companies to maintain their competitiveness to continuously work on improvements and always strive to be more effective. A more effective production process has the potential to contribute to a more sustainable society. This thesis is focused on how the production process at a steel tube manufacturing facility could be made more efficient to minimize the throughput time for length cut tubes. These tubes are often sold to manufacturers of mining equipment where they are used for drill rods. The problems in the production process has over the past year become more apparent since the demand for these products has risen due to the higher metal prices. By mapping the production flow unnecessary and costly operations can be identified and eliminated. The aim with this thesis is to minimize costs and achieve a more efficient production process for these tubes. The goal is to identify the bottlenecks and map the production flow of length cut tubes as well as producing technical and logistical solutions which enables a lower throughput time. To map the production flow observations and interviews were conducted where the operators were given the opportunity to share their thoughts on the problems. Based on the observations a Value Stream Mapping was conducted to identify the different operations and decide which of them were value adding. Two different mappings were made one that focused on when the tubes are cut in control station four. And one that looked at when they are moved and cut at a special cutting section. The next step was to measure the cycle times to determine where the bottlenecks were. In the control station the cycle times for the two saws after the control equipment were significantly higher than the control equipment and for the cutting machine after the saws the cycle time was even higher. In the control station the cycle time of the control equipment is dependent on the length of the tubes, therefore it was investigated how large quantities can be allowed at different lengths to avoid any interference in the control equipment. It was clear from the analysis that the bottlenecks were the two saws and the cutting machine. The solution is to transfer all the cutting of the tubes to the special cutting section. And to make sure no defects are left on the tubes when they are shipped to the customers the tubes are given a color marking at both ends that are supposed to be cut away. This solution has the potential to increase the production rate in the control station from 1.6 tubes per minute to 3 tubes per minute at an average length of 10 meters which amounts to a total time saving in the control station of 21 hours per year. The solution will save resources in the control station and raise the capacity. Due to the high tolerances there is however no higher yield but if the solution could be applied to other products this might decrease the scrap which would have positive effects both for the environment and the company.