Module 08.01 Key Concepts: Layout Design Options for Products and Services
In this section we will review the characteristics of many typical operational layouts.
An Office Layout is often reflected by a grouping of workers, their equipment, and spaces to provide comfort, safety, and movement of information. The movement of information is main distinction. Office Layouts are typically in state of flux due to frequent technological changes. Selection / design of a particular layout usually considers three physical and social aspects: Proximity, Privacy and Permission. In addition, these layouts are significantly impacted by information technology and the dynamic needs for space and services.
A Relationship Chart can be used to illustrate some inter-dependencies between functions and these key dimensions.
- Locate high-draw items around the periphery of the store
- Use prominent locations for high-impulse and high-margin items
- Distribute power items to both sides of an aisle and disperse them to increase viewing of other items
- Use end-aisle locations
- Convey mission of store through careful positioning of lead-off department
A Warehouse Layout typically is designed to optimize trade-offs between handling costs and costs associated with warehouse space. As such, the objective is to maximize the total “cube” utilization of the warehouse (utilize its full volume) while maintaining low material handling costs. Material handling costs are all those associated with the various transactions and movements: incoming transport, storage, locating and moving material, outgoing transport. It also includes other costs such as: equipment, people, material, supervision, insurance, depreciation and cost of damage and spoilage.
Warehouse density tends to vary inversely with the number of different items stored. Automated Storage and Retrieval Systems (ASRSs) can significantly improve warehouse productivity by an estimated 500%. Dock location is a key design element to be considered. Cross-Docking is a special approach that can minimize cost by eliminating the need to put away and then retrieve stock from storage locations.
notification as materials are unloaded.
A Fixed Position Layout is selected for large projects but is also quite relevant to other situations. With this type of layout, product remains in one place and workers and equipment come to site. This is complicate by the fact that space is limited at the site and different materials are required at different stages of the project. Therefore, the volume of materials needed is dynamic. Fixed Position Layouts are found in Airline Manufacturing, Ship Building, Construction, and yes, even in Operating Rooms. Limited space and long lead times can be addressed through completion of process elements / steps in an off-site product-oriented facility. This can significantly improve efficiency but is only possible when multiple similar units need to be created.
A Process-Oriented Layout is typically selected when flexibility is important. Like machines and equipment are grouped together that are flexible and capable of handling a wide variety of products or services. Scheduling can be difficult and setup, material handling, and labor costs can be high. Layout work centers are arranged so as to minimize the costs of material handling and minimize cost attributed to: number of loads (or people) moving between centers and the distance loads (or people) move between centers. There are many approaches that can be used to optimize Process Oriented Layouts. For example, three dimensional visualization software allows managers to view possible layouts and assess process, material handling, efficiency, and safety issues.
Work Cell Layouts are used to provide some of the benefits of a Process Layout but reduce unnecessary movements, lower costs, and speed throughput. Work Cell Location reorganizes people and machines into groups to focus on single products or product groups. Group technology identifies products that have similar characteristics for particular cells. In this case, production volume must justify the creation of work cells. However, cells can be reconfigured as designs or volume changes. Establishment of work cells requires identification of families of products; a high level of training, flexibility and empowerment of employees; and being self-contained, with its own equipment and resources. Mistake Proofing (poka-yoke) is often an accepted approach at each station in the cell. Work Cells generally provide many benefits:
- Reduced work-in-process inventory
- Less floor space required
- Reduced raw material and finished goods inventories
- Reduced direct labor cost
- Heightened sense of employee participation
- Increased equipment and machinery utilization
- Reduced investment in machinery and equipment
It is possible to create many different Work Cell Layout configurations.
A mathematical approach can be applied to staffing and balancing Work Cells.
- Fabrication line Builds components on a series of machines
- Machine-paced require mechanical or engineering changes to balance
- Assembly line puts fabricated parts together at a series of workstations
- Paced by work tasks and Balanced by moving tasks
The text provides a simple example to illustrate the approach.
Needed:
- The Task List, Task Times and Precedence Relationships – given above
- The Total Task Assembly Time – calculated as shown in the Table above.
- The Production Time Available – given above
- The required production output per day – given above
- The Required Cycle Time: Production Time per day / Required Output per day
- The Theoretical Min. # of Work Stations: Sum of Task Times / Cycle Time
- A Precedence Diagram – Constructed based on Information in the Table
- Workstation Assignments based on the selected Layout Heuristic
- The Efficiency: Sum of Task Times / (Actual # of Workstations x Cycle Time)
- Idle Time: (Actual # of Workstations x Cycle Time) – Sum of Task Times
The Precedence Diagram and calculation of Theoretical Minimum # of Workstations is shown in detail in the text.
In addition to the given data you will need to calculate the following in order to establish your final recommendation for Workstation structure.
- The Cycle Time
- The Minimum # of Workstations
To Calculate the Cycle Time
- Production Time per day (in minutes) / Required Output per day (in Units)
To Calculate Theoretical Minimum # of Workstations:
- Sum of Task Times (in minutes) / Cycle Time (in minutes)
I suggest that you go back to the Practice Homework and give this Process a try to see how it works for you. The Text Authors provide tools there to help you solve the problem and you will be able to practice without negatively impacting your grade.