Facility layout refers to the configuration of departments, employee workstations, customer service areas, material storage areas, restrooms, offices, computer rooms, and for the flow patterns of materials and people around into and within buildings.
As process planning and facility layout planning proceed, there is a continuous interchange of information between these two planning activities, because each affects the other. In operations strategy, the mix of competitive priorities that operation function can provide is: low production costs, fast and on-time deliveries, high-quality products and services, and product and volume flexibility.
The objectives that drive facility layouts must reflect an appropriate mix of these competitive priorities. Operations strategy drives facility planning, and facility layouts serve as a means of achieving operations strategy. The central focus of most manufacturing layouts is to minimize the cost of processing, transporting, and storing materials throughout the production system.
Materials Handling System: is the entire network of transportation that receives materials, stores materials in inventories, moves them between processing points within and between buildings, and finally deposits the finished products into vehicles that will deliver them to customers.
The following describes the different types of layout:
Process Layouts (functional layouts, or job shops)
Process layouts are the layouts that can handle varied processing requirements. They are designed to accommodate variety in product and processing steps. They are also called functional layouts, or job shops. If a manufacturing facility produces a variety of custom products in relatively small batches, the facility probably will use a process layout.
They use general-purpose machines that can be changed over rapidly to new operations for different product design. These machines are usually arranged according to the type of the process being performed. Product layouts are layouts that use standardized processing operations to achieve smooth, rapid, high-volume flow. They are designed to accommodate only a few product designs. Such layouts are designed to allow a direct material flow through the facility for products.
They use specialized machines that are set up once to perform a specific operation for a long period of time on one product. These machines are usually arranged into product department. Product layouts can take one of the following three forms:
- Production Line; which is a standardized layout arranged according to a fixed sequence of production tasks.
- Assembly Line; which is a standardized layout arranged according to a fixed sequence of assembly tasks.
- U-Shaped Layout; is a compact layout requiring half the length of a straight production line.
Fixed-Position Layouts are layouts in which the product or project remains stationary (fixed position) and workers, materials, equipments are moved as needed.
Combination Layouts (Hybrid Layouts)
Most manufacturing facilities use a combination of the three layout types, where the departments are arranged according to the types of processes but the products flow through on a product layout.
Cellular Manufacturing (CM) Layouts
- Machines are grouped into cells; each cell is formed to produce a single parts family, which require the same machines.
- The flow of parts tends to be more like a product layout than a job shop.
- Group Technology refers to the grouping into part families of items with similar design or manufacturing characteristics.
ANALYZING MANUFACTURING FACILITY LAYOUTS
The analysis of production lines is the central focus of the analysis of product layouts. The product design and the market demand for products determine the technological process steps and the required production capacity of production lines.The number of workers, attended and unattended machines, and tools required to provide the market demand must then be determined. This information is provided by line balancing.
It is the analysis of production that nearly equally divides the work to be done among work stations so that the number of workstations required on the production line is minimized. The goal of analysis of production line is to determine how many work stations to have and which tasks to assign to each work station so that the minimum number of workers and the minimum amount of machines are used to provide the required amount of capacity.
They are methods based on simple rules that have been used to develop good solutions for the problems aroused from the line balancing method. They are of two types; incremental utilization heuristic, and longest task-time heuristic.
Incremental Utilization Heuristic
It is also called Maximum Utilization Rate (MUTR). This method simply adds tasks to a workstation in order of task precedence one at a time until utilization is 100% or is observed to fall. Then this procedure is repeated at the next workstation for the remaining tasks. If a choice must be made between two or more tasks, the one with the smallest task time is added.
The condition to which this method is perfectly applied is when task times are equal to or greater than the cycle time. However, this method creates the need for extra tools and equipment. But if the primary focus of this method were to minimize the number of workstations or if the tools and equipment used in the production line are either plentiful or inexpensive, then this method would be appropriate.