Which factors can affect the assembly process and thus cease the production flow and cause a stop? This question was posed early in the study. The bachelor thesis was made in collaboration with Fläkt Woods AB. The study takes place in the plant’s final assembly step where all work is done manually. Fläkt Woods produces ventilation systems made to order, specifically designed for each customer. The study covers the process in which the products are completed. The assembly is a complex process which can be divided into two processes, one pre-assembly and one final assembly process. The pre-assembly consists of five sub-processes, which provides material to one of the three assembly lines located in the final assembly process.
The foundation of the question formulations are based on the stops occurring in the supply between the pre-assembly and the final one. The occurrence of a stop makes it unfeasible for the pre-assembly to deliver materials thus also the final assembly’s possibility to receive materials. This generates a risk where the pre-assembly may become full while the final assembly could become empty. Furthermore, it has an immediate effect on the production flow and the usage of resources. The purpose of the bachelor thesis was to examine what causes the disruptions in the supply.
To achieve this purpose, data was collected to establish a status report of the current situation by executing a process map. By observing the assembly process and applying root cause analysis the collaboration within the process and production flow were analysed to answer the posed question regarding the supply issue. This made up the foundation which the result of the study and action proposals where based on.
The analysis showed that the disruptions in the supply were caused by an imbalance between the workstations in the final assembly, as well as the three assembly lines. The imbalance was a result of the varying cycle time per station for each customer order-specific products, and the manual release method that Fläkt Woods uses for their orders. The large variation in cycle times affected the production flow to the point that queue occurred on the lines in the final assembly. Together, the queue and the current method to release production orders, caused disruptions in the supply between the pre- and final assembly, which resulted in unused resources.
In order to eliminate this imbalance the cycle time per station must be levelled off and the method to release production orders must be optimized in order to obtain an even flow of supply to all final assembly lines. The study presents suggestions as to how this could be managed with the currently existing recourses. By introducing an improved way of collaborating between workstations the cycle time per workstation could be levelled off. Furthermore, suggestions have been made regarding how assignments for the assemblers could be made less complicated. For instance the blur prints used could be simplified and more information should be made available for the worker who releases production orders. Meanwhile, the system which establishes the order of release need to be updated in order to correspond to Fläkt Woods product portfolio and their production layout. The thesis also presents more large-scaled suggestions for improvement. The suggestion that is believed to be the optimal solution for Fläkt Woods assembly process is to invest in a material square between the pre-assembly and final assembly. Furthermore, the line assembly layout ought to be changed into set assembly stations. This proposal eliminates the unnecessary interferences and the root causes that are connected to the imbalance and the manual method for release of production orders.
2016. , 84 p.