Designing a Process Layout

The process of designing the arrangement of the plant is not a haphazard approach. It follows some standard steps. This article will give ideas to micro enterprise owners and micro enterprise consultants the steps to plot the most cost efficient arrangement of a manufacturing plant or a small processing area.

  

Because of the nature of process design which is applied for batch processing, which typical of most micro and small enterprises, where crisscrossing of process steps within the facility cannot be avoided, the ultimate goal of designing process layout is to minimize movement or material handling cost, which is a function of the amount of material moved times the distance it is moved. 

This implies that departments that incur the most inter-department movement should be located closest to each other, and those that do not interact should be located further away. 

This article will present in brief some of the process layout designing procedures used by most designers. These include: Block diagramming and Layout Diagramming. Different authors call this process with different names. 

 Block Diagramming 

This process makes use of data on historical or predicted movement of material between departments in the existing or proposed facility. This data is summarized in a flow-cost matrix and will provide information as to which pairs of sections have high flow cost. Sections with high flow-cost must be placed near each other in the layout. Shown below is a sample block diagram with the flow matrix. 

Numbers placed on the line between blocks are the number of movements between that particular block. The cost of moving from one block to another may be obtained from company data (which may include operating cost of transport machines or labor cost). Generally, the farther the blocks from each other the greater the cost would be. These movements therefore can be multiplied by the distance of each block to obtain relative cost. Summing up the movement costs of different layouts will give idea to the designer which layout is more cost efficient. 

Sample block diagram

Sample flow cost matrix of the above diagram

 Relationship Diagramming 

This procedure is similar in approach to block diagramming but is more appropriate for designing process layouts when quantitative data are unavailable. Some authors call this Systematic Layout Planning (SLP). It requires subjective input from analysts or managers. It uses the Muther’s Grid which is a format for displaying manager preferences for department locations developed by Richard Muther. 

The preference information is coded into six categories associated with the five vowels:

A-absolutely necessary, 

E-especially important, 

I-important, 

O-okay, and 

U-undesirable,

 Plus the letter 

X-unnecessary. 

Sample Muther’s Grid and relationship diagram is presented below showing the relationship between sections of a company: 

 

 Figure (a) shows the initial diagram
while (b) shows the adjusted diagram showing a relationships
position closely as possible

Designing Service Layouts 

Most service organizations use process layouts. Service layouts are designed like process layouts in manufacturing firms, but the objectives differ. For example, instead of minimizing flow of materials, services may minimize the flow of paperwork or maximize customer exposure to as many goods. It also considers impact of location on sales and customer satisfaction. Service layouts should provide customers for easy access to the facilities: parking space, service counters, comfort rooms, etc. In addition, designing considers law compliance like provision of ramps for disabled clients and other concerns.