Chapter 6: Process Selection and Facility Layout
Process Layout Advantages
-Can handle a variety of processing requirements -Not particularly vulnerable to equipment failures -General-purpose equipment is often less costly and easier and less costly to maintain -It is possible to use individual incentive systems
Product Layout Disadvantages
-Creates dull, repetitive jobs -Poorly skilled workers may not maintain equipment or quality of output -Fairly inflexible to changes in volume or product or process design -Highly susceptible to shutdowns -Preventive maintenance, capacity for quick repair and spare-parts inventories are necessary expenses -Individual incentive plans are impractical
Job Shop
-Customized goods or services -Advantages: able to handle a wide variety of work -Disadvantages: slow, high cost per unit, complex planning and scheduling -Example: custom furniture
Facilities layout decisions arise when:
-Designing new facilities -Redesigning existing facilities
Product Layout Advantages
-High rate of output -Low unit cost -Labor specialization -Low material handling cost per unit -High utilization of labor and equipment -Established routing and scheduling -Routine accounting, purchasing, and inventory control
Continuous
-Highly standardized goods or services -adv: Very efficient, very high volume -disadv: Very rigid, lack of variety, costly to change, very high cost of downtime -Example: assembly lines, apple computers
Process Layout Disadvantages
-In-process inventories can be high -Routing and scheduling pose continual challenges -Equipment utilization rates are low -Material handling is slow and inefficient -Reduced spans of supervision -Special attention necessary for each product or customer -Accounting, inventory control, and purchasing are more involved
Batch
-Semi-standardized goods or -services -Advantages: flexibility; easy to add or change products or services -Disadvantages: moderate cost per unit, moderate scheduling complexity
Repetitive / Assembly
-Standardized goods or services -Advantages: low unit cost, high volume, efficient -Disadvantages: low flexibility, high cost of downtime
Process flexibility
-The degree to which the system can be adjusted to changes in processing requirements due to such factors as -Product and service design changes -Volume changes -Changes in technology
Cycle time
-the maximum time allowed at each workstation to complete its set of tasks on a unit -Cycle time also establishes the output rate of a line -can only be as fast as the weakest link
Service layouts
-warehouses and storage layouts -retail layouts -office layouts
Two key questions in process selection:
1. How much variety will the process need to be able to handle? 2. How much volume will the process need to be able to handle?
The Need for Layout Planning
1. Inefficient operations -High cost -Bottlenecks 2. Accidents or safety hazards 3. Changes in product or service design 4. Introduction of new products or services 5. Changes in output volume or product mix 6. Changes in methods or equipment 7. Changes in environmental or other legal requirements 8. Morale problems
Types of Processing
1. Job Shop 2. Batch 3. Repetitive / Assembly 4. Continuous
Basic Layout Types
1. Product Layout 2. Process Layout 3. Fixed-Position Layout
Key aspects of process strategy:
1. capital intensity 2. process flexibility
Process Selection has major implications for:
Capacity planning Layout of facilities Equipment Design of work systems
Two key factors of service layouts:
Customer contact Degree of customization
Why is line balancing important?
It allows us to use labor and equipment more efficiently To avoid fairness issues that arise when one workstation must work harder than another
Fixed-Position Layout
Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed (It (the product) can't move. Example: building a building, hoover dam)
Goal of Line Balancing
Obtain task grouping that represent approximately equal time requirements since this minimizes idle time along the line and results in a high utilization of equipment and labor
Non-Repetitive Processing
Process Layouts
Repetitive Processing:
Product Layouts
Process Selection
Refers to deciding on the way production of goods or services will be organized
Facilities Layout
The configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system
Designing Product Layouts: Line Balancing
The goal of a product layout is to arrange workers or machines in the sequence that operations need to be performed
Capital intensity
The mix of equipment and labor that will be used by the organization
Line Balancing
The process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements Making sure there are no bottlenecks
What can affect cycle time or output rate?
You can't change the time Equipment problems Absenteeism
Product Layout
layout that uses standardized processing operations to achieve smooth, rapid, high volume flow
Process Layout
layouts that can handle varied processing requirements
Precedence Diagram
look at chart A diagram that shows elemental tasks and their precedence requirements
Product layout
look at chart layout that uses standardized processing operations to achieve smooth, rapid, high volume flow
Process Layouts
look at chart layouts that can handle varied processing requirements
Output rate =
operating time per day (minutes) / cycle time
Cycle time =
operating time per day (minutes) / desired output rate
