Balancing the production flow in prefabrication of wooden houses

The industrialization of wooden house building processes from traditional on-site production to off-site prefabrication is challenging, concerning the possibility of effective handling of numerous product variants, where each house is more or less unique. To obtain high productivity in the production, a well-balanced flow with minimization of waste is of great importance. In Sweden, many off-site house producers are in the starting phases of introducing advanced automation technologies in their production processes and the need for a more detailed process control therefore increases. In previous studies, the installation of windows has been identified as a demanding step in the prefabrication process, since it often creates a bottleneck i.e. the most overloaded part of process (Slack et al., 2016) and thus negatively affects the cycle-time and a balanced production flow.This study aims to understand, how the effectiveness of windows installations could be improved. By using a multiple case-study methodology, processes of several companies are compared and discussed. Further, suggestions for improvements are made for one case company. The results show that a replacement of the windows installation could (a) shorten the cycle-time of one wall by more than 10 %, (b) reduce the queueing time for the entire wall assembly process by more than 48 % and consequently (c) help to create a more balanced production flow