Material Flow Map and Layout Optimization: action plan and software validation

During the “life” of an industrial plant, many changes happen. Starting from an initial configuration of production lines, manufacturing and assembly departments, tools and equipment rooms, the plant layout could change because of new and different needs. Often, the above layout modifications are not correctly studied and optimized, causing problems in the management of worker movement and material flow. The main configurations of a firm, closely linked to the production quantity of each component, are: “product” or “process” layouts. In the case of a product layout, we arrange activities in a line according to the sequence of operations for a particular product or service; instead in the case of a process layout, similar activities are grouped together in departments according to the process or function they perform. The “product” configuration (commonly called “flow-shop”) is generally more automated and efficient; while in the other side, the “process” configuration (commonly called “job-shop”) is more flexible and manual. The present work suggests the main steps to verify the layout of an industrial plant organized in departments (“process” layout), in order to improve material flow, reducing production lead time, warehouse and workplace. The work suggests the adoption of different tools, such as: paths chart, product-quantity data sheet, flow process chart, from-to analysis, relationship chart of service and production activities, etc. In particular, we have applied the above tools to a company working in the field of electro-mechanical components. First of all, it is necessary to study the current layout, manufacturing, storage and service areas. Subsequently we need to map the material flow, starting from products information, such as: bill of materials; manufacturing cycles; ordering data. By matching layout and product information, many criticalities are pointed out. The material flow can be visualized on the plant plan, by using right codifications (measurement units and standard symbols). It is possible to value quantities and distances. Thanks to the mapping phase, it is possible to recognize the value stream and consequently the non-value activities. After the construction of the material flow map, it is necessary to draw the relationship chart. In fact, to improve the current layout, not only considerations about materials are required, but also different ones. We need information about exchange of documents rather than equipment and tools between departments. At this point, in order to adopt the right actions, it is important to define our goals: flow linearization, distance and material exchange reduction, workplace and warehouse areas saving, etc. For each goal, we can define a particular index to value the effectiveness of our choices; however it is impossible to find an unique solution able to improve all the defined indexes at the same time. Therefore, the work proposes new approach and criteria able to combine different indexes and goals. Finally, it is interesting to validate the taken choices trough customized or commercial software. In particular we have used the improvement algorithm CRAFT (Computerized Relative Allocation of Facilities Technique), based on the minimization of the transportation cost. It is more widely used than ALDEP and CORELAP, that consider relationships between departments more important. Thanks to that commercial optimizer software, it is possible to verify the goodness of the layout modifications proposed. The present work formalizes an approach for mapping material flow and optimizing plant layout, through the integration of several instruments, less or more complex, and the definition of combined indexes and criteria.