1. Process Layout
Chapter 7
July 20, 2005

2. Objectives of Facility Layout
Minimize material handling costs
Utilize space efficiently
Utilize labor efficiently
Eliminate bottlenecks
Facilitate communication and interaction between workers, between workers and their supervisors, or between workers and customers
Reduce manufacturing cycle time or customer service time
Eliminate waste or redundant movement
Facilitate the entry, exit, and placement of material, products, or people
Incorporate safety and security measures
Promote product and service quality
Encourage proper maintenance activities
Provide a visual control of operations or activities
Provide flexibility to adapt to changing conditions

3. Layout Types (a) Layout of a job shop (b) Layout of a production line
Foundry
Milling
machines
Lathes
Grinding
Painting
Drills
Office
Welding
Forging
(a) Layout of a job shop
This shows the basic job shop layout.
Station 1
Station 2
Station 3
Station 4
(b) Layout of a production line
Figure 7.3 5

4. Hybrid Layout Cellular layouts Flexible manufacturing systems
Group machines into machining cells
Flexible manufacturing systems
Automated machining & material handling systems
Mixed-model assembly lines
Produce variety of models on one line

5. Hybrid Layout: Group Technology
Machine 1
Machine 2
Machine 3
Machine 4
Machine 5
Materials in
Finished goods out
One Worker, Multiple Machines
This slide presents Figure 10.3 for discussion.
Figure 7.4 14

6. Receiving and shipping
Group Technology
Drilling D
Grinding G
Milling M
Assembly A
Lathing
Receiving and shipping L
This sequence is based on Figure 10.5 and shows the basic job shop layout prior to the introduction of GT and builds automatically.
(a) Jumbled flows in a job shop without GT cells
Figure 7.5 14

7. Group Technology (b) Line flows in a job shop with three GT cellsM G
Cell 1
Cell 2
Assembly area A D
Shipping
Receiving
This sequence shows how a shop using three GT cells improves the flows. This sequence builds automatically.
(b) Line flows in a job shop with three GT cells
Figure 7.5 18

8. Cellular Layout HM VM
Identify families of parts with similar flow paths
Group machines into cells based on part families
Arrange cells so material movement is minimized
Locate large shared machines at point of use
Worker 3 VM L
Worker 2 G L
Final inspection
Finished part S
Worker 1
Out In

9. Advantages/Disadvantages of Cellular Layout
Reduced material handling and transit time
Reduced setup time
Reduced work-in- process inventory
Better use of human resources
Easier to control
Easier to automate
Disadvantages
Inadequate part families
Poorly balanced cells
Expanded training and scheduling of workers
Increased capital investment

10. Designing Flexible-Flow Layout
Gather Information
Space requirement
Available space
Closeness factors
Other considerations
Develop block plan
distance measure
Calculating a weighted-distance score
Design a detailed layout

11. Block Diagram [Problem 5-5]
The design committee of a hospital has collected data on patient movement from similar facilities in hopes of making the new facility more efficient and customer-friendly. Improve the layout using weighted-distance score
Initial Layout
Patient Movement To
From 1 2 3 4 5 6 - 50 10 25
100 30 40 20 60

12. Designing Line-Flow Layouts
Line Balancing: the assignment of work to stations in a line so as to achieve the desired output rate with smallest number of workstations
2 constraints in line balancing:
1. Precedence requirements
Physical restriction, order of operations
2. Cycle time restrictions
Max. operating time allowed for each workstation
Depend on demand rate, production time

13. Assembly Line Balancing Concept
Question: Suppose you load work into the three work stations below such that each will take the corresponding number of minutes as shown. What is the cycle time of this line?
Station 1
Minutes per Unit 6
Station 2 7
Station 3 3
Answer: The cycle time of the line is always determined by the work station taking the longest time. In this problem, the cycle time of the line is 7 minutes. There is also going to be idle time at the other two work stations.

14. Line Balancing Process
1. Draw and label a precedence diagram.
2. Calculate the desired cycle time required for the line.
3. Calculate the theoretical minimum number of workstations.
4. Group elements into workstations, recognizing cycle time and precedence constraints.
5. Calculate the efficiency of the line.
6. Stop if theoretical minimum number of workstations on an acceptable efficiency level reached. If not, go back to step 4.

15. Ex: Line Balancing (also see Example 7.3)
A company must produce 600 unit output in a 40-hour week. Given the following conditions, balance the assembly line
Work Element
Precedence
Performance Time (min) A B C D E F -
A, E
C, D 1 2 4 3

16. Ex: Line Balancing Additional Example
The work elements, precedence requirements and time requirements to assemble a picture frame are shown here.
Elements
Description
Precedence
Time (min) A B C D E F G H I
Attach left frame side to top of frame
Attach right frame side to bottom of frame
Attach left and right frame subassemblies
Cut 8-inch by 10-inch glass
Cut 8-inch by 10-inch cardboard
Place glass into frame
Place cardboard into frame
Secure cardboard and glass
Apply descriptive label to glass -
A, B
C, D
E, F
F, G
0.35
0.70
0.50
0.20
0.10
Construct a precedence diagram of the process and label task times.
Set up an assembly line capable of producing 1,600 frames per 40-hour week.
Calculate the efficiency and balance delay of the line.
Calculate the maximum number of frames that can be assembled each week.
Rebalance the line for maximum production. Indicate the composition of each station.
Assume the company can sell as many frames as can be produced. If workers are paid $8 an hour and the profit per frame is $5, should the production quota be set to the maximum? Assume one worker per station.