1 Process Layout Chapter 7 July 20, 2005. Dr. Karndee Prichanont IES371 1/2005 2 Objectives of Facility Layout Minimize material handling costs Utilize

1

Process LayoutProcess Layout

Chapter 7

July 20, 2005

2

Dr. Karndee Prichanont IES371 1/2005

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(a) Layout of a job shop

Figure 7.3Figure 7.3

FoundryMilling

machines

LathesGrinding

Painting Drills

Office

Welding

Forging

(b) Layout of a (b) Layout of a production lineproduction lineStation 1 Station 2 Station 3 Station 4

4


Hybrid LayoutHybrid Layout Cellular layouts

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 4Machine

5

Materials in

Finished goods out


One Worker, Multiple MachinesOne Worker, Multiple Machines

6


Group Technology


Drilling

D D

D D

Grinding

G G

G G

G G

Milling

M M

M M

M M

Assembly

A A

A A

Lathing

Receiving and shipping

L

L L

L L

L L

L

(a) Jumbled flows in a job shop without GT cells(a) Jumbled flows in a job shop without GT cells

7


Group Technology

(b) Line flows in a job shop with three GT cells (b) Line flows in a job shop with three GT cells

Cell 3

L M G G

Cell 1 Cell 2

Assembly area

A A

L M DL

L MShipping

D

Receiving

G


8


Cellular Layout

1. Identify families of parts with similar flow paths

2. Group machines into cells based on part families

3. Arrange cells so material movement is minimized

4. Locate large shared machines at point of use

In OutWorker 1

Worker 2

Worker 3

S

L

HM

VM

G

VM

L

Final inspection

Finished part

9


Advantages/Disadvantages of Cellular LayoutAdvantages/Disadvantages of Cellular Layout

Advantages 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 Layout1. Gather Information

Space requirement Available space Closeness factors Other considerations

2. Develop block plan distance measure Calculating a weighted-distance score

3. Design a detailed layout

11


Block Diagram Block Diagram [Problem 5-5][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

Patient Movement To

From 1 2 3 4 5 6

1 - 50 10 25 10 100

2 - 30 40 20 20

3 40 - 20 60 40

4 10 10 - 10 40

5 30 20 10 - 30

6 40 60 50 20 -

5 2 3

1 6 4

Initial Layout

12


Designing Line-Flow LayoutsDesigning 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

Station 1

Minutes per Unit 6

Station 2

7

Station 3

3

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?

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 ProcessLine 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 BalancingEx: Line Balancing(also see Example 7.3)(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)

ABCDEF

-AB

A, E-

C, D

122434

16


Ex: Line BalancingEx: Line BalancingAdditional ExampleAdditional Example

The work elements, precedence requirements and time requirements to assemble a picture frame are shown here.

1. Construct a precedence diagram of the process and label task times.2. Set up an assembly line capable of producing 1,600 frames per 40-hour week.3. Calculate the efficiency and balance delay of the line.4. Calculate the maximum number of frames that can be assembled each week.5. Rebalance the line for maximum production. Indicate the composition of each station.6. 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.

Elements Description Precedence Time (min)

ABCDEFGHI

Attach left frame side to top of frameAttach right frame side to bottom of frameAttach left and right frame subassembliesCut 8-inch by 10-inch glassCut 8-inch by 10-inch cardboardPlace glass into framePlace cardboard into frameSecure cardboard and glassApply descriptive label to glass

--

A, B--

C, DE, FF, GD

0.350.350.700.500.500.200.200.500.10

Documents

1 Process Layout Chapter 7 July 20, 2005. Dr. Karndee Prichanont IES371 1/2005 2 Objectives of Facility Layout Minimize material handling costs Utilize