mp_07 facility layout

Facility Layout Facility Layout

Chapter 6A

1

Facility Layout Defined Facility layout can be defined as the

process by which the placement of: departments,

workgroups within departments,

workstations

machines, and

stock-holding points

within a facility are determined. 2

This process requires the following inputs:

Specification of objectives of the system in terms of output and flexibility.

Estimation of product or service demand on the system.

Processing requirements in terms of number of operations and amount of flow between departments and work centers.

Space requirements for the elements in the layout.

Space availability within the facility itself.

Facility Layout Defined

3

4

Basic Production Layout FormatsProcess Layout

Product Layout

Group Technology (Cellular) Layout

Fixed-Position Layout

5

Product Layout Layout that uses standardized processing operations to

achieve smooth, rapid, high volume flow.

Process Layout Layout that can handle varied processing requirements.

Fixed-Position Layout Layout in which the product or project remains

stationary, and workers, materials, and equipment are moved as needed.

Basic Production Layouts

6

Basic Production Layouts

Cellular Manufacturing (Layout) Layout in which machines are grouped into a

cell that can process items that have similar processing requirements

Group Technology The grouping into part families of items with

similar design or manufacturing characteristics

http://www.makita.com/en-us/Modules/Tools/Default.aspx?CatID=26

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Layout Structures Job shop [Process]

or Workcenter

Batch [Process] or Manufacturing Cell

Assembly line [Product]

Continuous flow [Product]

8

Process Layout (Job Shop)

FED

A B CProduct 1

Product 2

Product 3

Product 1

Product 2

Product 3

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Process Layout –Position of equipment is dominant consideration

10

11

Process-Focused Strategy

Facilities are organized by process Similar processes (i.e. equipment)

are together Example: All drill presses are together

Low volume, high variety products ‘Jumbled’ flow Other names

Intermittent process Job shop

12

Process Layout: Interdepartmental Flow

GivenThe flow (number of moves) to and from all

departmentsThe cost of moving from one department to

anotherThe existing or planned physical layout of the

plantDetermineThe “best” locations for each department, where

best means interdepartmental transportation, or flow, costs

13

Process Focused Strategy -Pros & Cons Advantages

greater process flexibility more general purpose equipment lower initial capital investment

Disadvantages more “specialist” trained personnel

required more difficult production planning and

control

14

Layout Structures

Job shop [Process]

Batch [Process]



15

Product Layout (Flow Shop)

FED

A B C

Product 2

Product 3

Product 1

FED

Product 2

Product 3

Product 1

16

Product Layout –Flow of product is dominantconsideration

17

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Product-Focused Strategy Facilities are organized by product High volume, low variety products Where found

Discrete unit manufacturing Continuous process manufacturing

Other names Line flow production (flow shop) Continuous production

19

Product-Focused StrategyPros & ConsAdvantages

lower labor skills easier production planning and controlhigher equipment utilization

Disadvantages lower product flexibilitymore specialized (customized)

equipmentusually higher capital investment

20

Layout Structures

Job shop [Process]

Batch [Process]



Group Technology a.k.a. Cell

21

Group Technology:Transition from Process Layout

1. Grouping parts into families that follow a common sequence of steps.

2. Identifying dominant flow patterns of parts families as a basis for location or relocation of processes.

3. Physically grouping machines and processes into cells.

22

Departmental (Batch Process) Specialization

Saw Saw

Lathe PressPress

Grinder

LatheLathe

Saw

Press

Heat Treat

Grinder

Batch/Lot Thinking

23

Press

Lathe

Grinder

Grinder

A

2

BSaw

Heat Treat

LatheSaw Lathe

PressLathe

1

Group Technology Cells Single-Piece Flow Thinking

24

Assembly Line Cells

Group Technology

25

Benefits of Group Technology Changeover setup time reduced for

tooling and equipment Automation may be possible Operator may be specially (specifically)

trained with improved expertise Quality of output improved In-process inventory reduced Productivity improved Lead time reduced Improved human relations

26

27

Fixed Position (or Project) Layout

Question: What are our primary considerations for a fixed position layout?

Answer: Arranging materials and equipment concentrically around the production point in their order of use.

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Volume and Variety of Products

Poor Strategy(Fixed costs and cost changing to other products

are high)

Volume andVariety ofProducts

Low Volume HighVariety Process

(Intermittent)

RepetitiveProcess

(Modular)

High VolumeLow Variety

Process(Continuous)

One or very fewunits per lot

Projects

Very small runs, highvariety

Job Shops

Modest runs, modestvariety

DisconnectedRepetitive

Long runs, modestvariations

ConnectedRepetitive

Very long runs,Changes inattributes

Continuous

Poor Strategy(High variable

costs)

Aluminum part

Cell Assembly

Motor Assembly

Part Molding

Tool Design

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Summary - Comparison

Process Focus Product Focus1. Product: Smallquantity, largevariety

1. Product: Largequantities, smallvariety

2. Equipment:General purpose

2. Equipment:Special-purpose

3. Operators broadlyskilled

3. Operators lessbroadly skilled

4. Many jobinstructions

4. Few work orders and job instructions;standardization

Bank

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Process/Product ContinuumProcess Focused

(intermittent process)Product Focused

(continuous process)

Continuum

High variety, low volumeLow utilization

General-purpose equipment

Low variety, high volumeHigh utilization

Specialized equipment

Group Technology /Cell

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Station 1

Minutes per Unit 6

Station 2

7

Station 3

3

Assembly Lines Balancing Concepts

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.

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Main Points of Line BalancingAn analysis of production linesAim: To nearly equally divide work

between workstations while meeting required output

Has objectives toMaximize efficiencyMinimize number of

work stations

33

Example of Line Balancing You’ve just been assigned the

job a setting up an electric fan assembly line with the following tasks:

Task Time (Mins) Description PredecessorsA 2 Assemble frame NoneB 1 Mount switch and handle AC 3.25 Assemble motor housing NoneD 1.2 Mount motor housing in frame A, CE 0.5 Attach blade DF 1 Assemble and attach safety grill EG 1 Attach cord BH 1.4 Test F, G

34

Example of Line Balancing: Structuring the Precedence Diagram

Task PredecessorsA None

A

B A

B

C None

C

D A, C

D

Task PredecessorsE D

E

F E

F

G B

G

H F, G

H

35

Example of Line Balancing: Precedence Diagram

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

Question: Which process step defines the maximum rate of production?

Answer: Task C is the cycle time of the line and therefore, the maximum rate of production.

36

Example of Line Balancing: The Bottleneck

Task Time (Mins) Description PredecessorsA 2 Assemble frame NoneB 1 Mount switch AC 3.25 Assemble motor housing NoneD 1.2 Mount motor housing in frame A, CE 0.5 Attach blade DF 1 Assemble and attach safety grill EG 1 Attach cord BH 1.4 Test E, G

Max Production = Production time per day

Bottleneck time=

420 mins3.25 mins / unit

= 129 units

Total 11.35 Minutes = Sum of the task times ≈ Operation time 37

Process Performance Metrics

Operation time = Setup time + Run time

Throughput time = Average time for a unit tomove through the system

Velocity = Throughput timeValue-added time

[time to produce each unit x batch size]

[time to prepare a machine or system to make a particular item or unit]

[for a particular machine or contiguous discrete system]

[time unit spends being worked on plus time spent waiting in queue]

[time unit spends being worked or the cumulative activity operation times]

[a.k.a. Throughput Ratio]

[> or = 1]

38

Example of Line Balancing: Determine Cycle Time

Required Cycle Time, C = Production time per periodRequired output per period

C = 420 mins / day100 units / day

= 4.2 mins / unit

Question: Suppose we want to assemble100 fans per day. What would our cycletime have to be?

Answer:

Question: What else can the 4.2 min time be called other than cycle time? (i.e. ‘Pull’) 39

Task Time (Mins) Description PredecessorsA 2 Assemble frame NoneB 1 Mount switch AC 3.25 Assemble motor housing NoneD 1.2 Mount motor housing in frame A, CE 0.5 Attach blade DF 1 Assemble and attach safety grill EG 1 Attach cord BH 1.4 Test E, G

Example of Line Balancing: Determine Theoretical Minimum Number of Workstations

Question: What is the theoretical minimum number of workstations for this problem?

40

Example of Line Balancing: Determine Theoretical Minimum Number of Workstations

Question: What is the theoretical minimum number of workstations for this problem?

Answer: Theoretical Min. Number of Workstations, N

N = Sum of task times (T)

Cycle time (C)

t

t

N = 11.35 mins / unit

4.2 mins / unit= 2.702, or 3t

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Example of Line Balancing: Rules To Follow for Loading Workstations

Primary: Assign tasks in order of the largest number of following tasks.

Secondary (tie-breaking): Assign tasks in order of the longest operating time

Time Time

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A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

Station 1 Station 2 Station 3

Task Followers Time (Mins)A 6 2C 4 3.25D 3 1.2B 2 1E 2 0.5F 1 1G 1 1H 0 1.4

4.2 min 4.2 min

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A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1


A (4.2-2=2.2)


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A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

A (4.2-2=2.2)B (2.2-1=1.2)



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A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2



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A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

C (4.2-3.25)=.95


A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2


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C (4.2-3.25)=.95

Idle = .95

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1


A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2


48

C (4.2-3.25)=.95

Idle = .95

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

D (4.2-1.2)=3


A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2


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A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

C (4.2-3.25)=.95

Idle = .95

D (4.2-1.2)=3E (3-.5)=2.5


A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2


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A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

C (4.2-3.25)=.95

Idle = .95

D (4.2-1.2)=3E (3-.5)=2.5F (2.5-1)=1.5


A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2


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Which station is the bottleneck? What is the effective cycle time?

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

C (4.2-3.25)=.95

Idle = .95

D (4.2-1.2)=3E (3-.5)=2.5F (2.5-1)=1.5H (1.5-1.4)=.1Idle = .1


A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2


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Example of Line Balancing: Determine the Efficiency of the Assembly Line

Efficiency =Sum of task times (T)

Actual number of workstations (Na) x Cycle time (C)

Efficiency =11.35 mins / unit(3)(4.2mins / unit)

=.901

53

Assembly Line BalancingThe General Procedure Determine cycle time by taking the demand

(or production rate) per day and dividing it into the productive time available per day

Calculate the theoretical minimum number of work stations by dividing total task time by cycle time

Perform the line balance and assign specific assembly tasks to each work station

54

Assembly Line Balancing Steps1. Determine tasks (operations)2. Determine sequence3. Draw precedence diagram4. Estimate task times5. Calculate cycle time 6. Calculate number of work stations7. Assign tasks (load workstations) 8. Calculate efficiency

Basic Project

Mgt.

55

Mixed-Model ProcessingShort cycle-interval (time) Production of a variety of types,

sizes, or models of a product family on the same line or within the same cell.

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Example – The Fresh Bakery: Cakes

Daily sales for: 24 Product L (Lemon Pound)

12 Product M (Chocolate Mud)

3 Product N (Nine Layer Carrot)

Questions:What is the best schedule for these

products?What are we assuming for this schedule to

work?57

ExampleDaily sales for: 24 Product L

12 Product M3 Product N

Step 1 - find minimum ratio8 L -- 4 M – 1 N

Step 2- determine number of cycles39/13 = 3

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Example In order to meet daily demand, this

cycle will have to repeat 3 timesStep 3 - find the mix of the units that

is most repetitive.LLM LLM N LLM LLM

What are we assuming for this schedule to work?

Demand is uniform and our objective is to avoid inventory.

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Mixed Model

Auto Industry

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mp_07 facility layout

Documents

product layout layout

process layout layout

product layout flow

fixedposition layout

physical layout

estimation of product

product high volume

high volume flow