Redefinition of Tasks to Increase the Process Capacity of Bottlenecks: Adjustment to a Real Case of Cutting Process of Structural Profiles of Carbon Steel

Abstract

Once identified the bottleneck process, that one that limits the total capacity of the system, the following logical step is tied to the decision of how to optimize it. It will be necessary to know all the tasks that influence the speed of the process. The limitations can appear as materials, information, persons, machinery or any another aspect. It is very usual to connect the limitation of the process to aspects that, though indirectly if they determine the same one, they are not really those on which it is necessary to work hard. Therefore, the efficiency in the redesign of the process does not have the desired result. The detailed analysis of the procedure of each task that takes part in the process at some point of its accomplishment, allows knowing with accuracy the proper restrictions as well as the critical points on which it is necessary to work. This article provides a guide to the implementation of process improvements (regardless of the process in question) by identifying the constraints and solving them. The solutions are intended to increase the process speed, which is converted to a capacity increase of the whole organization. In the business of transformation of structural steel we meet the process of cutting as the common bottleneck of different organizations located in this sector. The standard product supplied by the manufacturers of steel is characterized by standard lengths. For the construction of structures, where the lengths are variable, it needs additional cutting to obtain specific lengths. This transformation of the base product is habitually done by appropriate machinery, and the capacities of cutting are based with the own process time of cutting. The optimization of this one task, measure as the increase of the number of hours of effective cutting, is obtained reducing to the maximum all the restrictions that limit the speed of the process. In our practical case, the solution to the bottleneck of cutting to allow the increase of sales could be solved by subcontracting, buying new tangible fixed assets or optimizing the process. The latter aspect is the developed one in this case of study. The cutting program is subordinated to the optimization of the bottleneck. We took measurements before the redesign of the process as well as after the changes. The result is cutting capacities much better than the initial values. This case of study is used in different degrees and master class as an example of the steps to identify, to analyze and to re-design a process. In addition, we emphasize the importance of measuring to understand the successfulness of the changes. For the real organizations, the redesign is fundamentally based on the learning and growth perspective. People who take part in the process are instructed in order to obtain a coherent adjustment with the needs of the new way of processing.