05 facil ty design layout

7/31/2019 05 Facil Ty Design Layout

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Facility Design and Layout

Henry C. Co

Technology and Operations Management,

California Polytechnic and State University


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Facility Design and Layout (Henry C. Co) 2

Facility Design

Facility layout: Arrangement of machines,

storage areas, and/or work areas usuallywithin the confines of a physical structure,such as a retail store, an office, awarehouse, or a manufacturing facility.

Factors that influence layout Volume, weight of items to be produced.

Nature of the service to be provided.

Cost of the building to house the operation.

The product mix that must have a facility. The fragility of the product or component.


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A Good Layout ...

Reduces bottlenecks in moving people or

material. Minimizes materials-handling costs.

Reduces hazards to personnel.

Utilizes labor efficiently.

Increases morale. Utilizes available space effectively and

efficiently.

Provides flexibility.

Provides ease of supervision. Facilitates coordination and face-to-face

communication where appropriate.


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Flow-Line Layout

Applicable to both manufacturing and non

manufacturing operations. Arrange machines and/or workers in

accordance with the sequence of operationsfor a given product or service.

Advantages of flow-line layout Reduces materials handling.

Accommodates small amounts of work in process.

Reduces transit times.

Simplifies production planning and control

systems. Simplifies tasks, enabling unskilled workers to

learn task quickly.


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Disadvantages of flow-line layout

Lack of process flexibility. Lack of flexibility in timing: the product can not

flow through the line faster than the slowest taskcan be accomplished unless that task is performedat several stations.

Large investments: special-purpose equipmentand duplication is required to offset lack offlexibility in timing.

Dependence of the whole on each part: abreakdown of one machine or absence of enoughoperators to staff all work stations may stop theentire line.

Worker fatigue: workers may become bored bythe endless repetition of simple tasks.


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Process Layout

Grouping together of machines and/or

workers doing similar tasks. Applicable to both manufacturing and non

manufacturing operations. Advantages

Flexibility: equipment and personnel can be used

where they are needed. Smaller investment in equipment: duplication is

not necessary unless volume is large. Expertise: supervisors for each department

become highly. knowledgeable about theirfunctions

Diversity of tasks: changing work assignmentsmake work more satisfying for people who prefervariety.


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Disadvantages

Lack of process efficiency: backtracking and longmovements may occur in the handling ofmaterials.

Lack of efficiency in timing: workers must waitbetween tasks.

Complication of production planning and control.

Cost: workers must have broad skills and must bepaid higher wages than assembly line workers.

Lowered productivity: because each job is

different it requires different setups and operatortraining.


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Fixed Position Layout

Manufacturing and non-manufacturing

operations of bulky or fragile products, e.g.,ships and planes.

Move machines and/or workers to the site;products normally remains in one locationfor its entire manufacturing period.

Advantages of fixed position layout Reduces movement of work items; minimizes

damage or cost of moving.

More continuity of the assigned work force (since

the item does not go from one department toanother). This reduces the problems of re-planning and instructing people each time a newtype of activity is to begin.


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Disadvantages of fixed position layout

Since the same workers are involved in moreoperations, skilled and versatile workers arerequired. The necessary combination of skills maybe difficult to find and high pay levels may benecessary.

Movement of people and equipment to and fromthe work site may be expensive.

Equipment utilization may be low because theequipment may be left at a location where it willbe needed again in a few days rather than movedto another location where it would be productive.


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Group Technology Layout

Definition of Group Technology

Group technology is the technique ofidentifying and bringing togetherrelated or similar parts in a production

process in order to utilize the inherenteconomy of flow production methods.

V. B. Solaja,Institute of Machine Tools, Belgrade, Yugoslavia


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Group Technology layout is also called

manufacturing cell layout. Example:

A plant producing 10,000 part numbers may beable to group the parts into 50 or 60 families.Each family would possess similar design and

manufacturing characteristics. Hence, the processing of each member of a given

family would be similar, and this results inmanufacturing efficiencies in the form of:

Reduced set-up,

Lower in-process inventories, Better scheduling,

Improved tool control,

Standard process plan.


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Concept

Many problems are similar, by grouping

similar problems, a single solution can befound to a set of problems, thus saving timeand effort.

A manufacturing philosophy in which similar

parts are identified and grouped together totake advantage of their similarities in designand manufacturing.

A technique for identifying and bringing

together related or similar components inorder to take advantage of their similaritiesin the production process.


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Concept Design Manufacturing

Many problems are

similar

Similar Shapes SimilarManufacturingProcesses

Group Similar

Problems

Design Families Production Family

Single Solution ofProblems

One standard designplus minormodification

One standardprocess plan to afamily andmodification andextension


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Manufacturing Cell Cellular manufacturing is the physical division of the

manufacturing facilities into production cells. Each cell is designed to produce a part family. A part family is

a set of parts that require similar machinery, tooling, machineoperations, and/or jigs and fixtures.

The parts within the family normally go from raw material tofinished parts within a single cell.

Justification Batch production

Only 5% of the lead time in producing a part is direct workingtime; 95% of the time, the part is waiting.

The 5% direct working time includes 30% actual processing and70% for positioning, chucking, gauging, etc.

Hence, only 1.5% is accounted for actual machining.

Cellular manufacturing directs its effort towards the remaining98.5% by organizing the plant layout according to work cell,

rather than functions. A work cell is a unit that includes all ofthe machines required to produce a family of parts.


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Advantages/Disadvantages

Advantages

Implied reduction of necessary control

Reduced material handling

Reduced set-up time

Reduced tooling Reduced in-process inventory

Reduced expediting

Increase operator expertise

Improved human relations.


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Disadvantages

Reduced shop flexibility Possible reduced machine utilization

Possible extended job flow times

Possible increased job tardiness.

Implementation Issues Reorganization - machine layout need

reorganization every so often.

Work cell supervision - supervisors must be expertin several field (milling, turning, grinding, etc.)represented in the cell.

Shop floor control / production planning - cellconcept leads to unbalanced workload onmachines.


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Analysis of Layout By Process

Steps involved:

1. Determine the size of each department.

2. Determine the arrangement of thedepartment with respect to one another.

3.

Determine the arrangement of theequipment and people within eachdepartment.


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Closeness Rating Definition

A Absolutely necessary

E Essentially important

I Important

O Ordinary closeness

U Unimportant

U Undesirable

Analysis of Layout By Process

Richard Muther's Systematic Layout

Planning Utilizes a grid matrix to display the ratings

of the relative importance of the distancebetween department

Closeness ratings:


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Distance Measurements

Typically measured from department center

to department center. Euclidean distances are appropriate when

the layout space is very open and movementwithin it can follow a direct path.

Rectilinear (sometimes called rectangular)distance is more appropriate for layoutsaisles or hallways where one generallyreaches a destination after making one or

more right turns.


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Load Distance Analysis

Each department is 10 feet by 10 feet,

distances are rectilinear, which of thefollowing two layouts is better?

Layout A Layout B

3 8

7 4

1 10

9 2

6 5

4 7

10 1

2 9

5 6

8 3


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Routing/Travel Distances

Product DepartmentProcessing Sequence

Quantity ProcessedPer Month

A 1 5 410 1,000 units

B 2 6 3 9 2,000

C 210 1 9 3,000

D 1 7 810 1,000

E 2 5 6 9 2,000

F 1 7 410 4,000


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Routing/Travel Distances

Distance Between

Departments (feet)

Distance Between

Departments (feet)

Flow Layout A Layout B Flow Layout A Layout B

1 5 30 30 39 30 20

1 7 10 10 45 30 30

1 9 10 10 47 10 10

1 10 10 10 410 10 10

2 5 10 10 56 10 10

2 6 20 20 69 10 10

2 10 10 10 78 20 50

3 6 40 10 810 20 30


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Solution (1/2)

Compute the total travel for each

product through each layoutalternative.

Product

Department

Processing

Sequence

Distance per

Product (feet)

Layout A

Distance per

Product (feet)

Layout B (feet)

A 1 5 410 30+30+10= 70 30+30+10= 70

B 2 6 3 9 20+40+30= 90 20+10+10= 50

C 210 1 9 10+10+10= 30 10+10+10= 30

D 1

7

8

10 10+20+20= 50 10+50+30= 90E 2 5 6 9 10+10+10= 30 10+10+10= 30

F 1 7 410 10+10+10= 30 10+10+10= 30


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Solution (2/2)

Compute total distance traveled per

month by each product through eachlayout alternative.

Units per Distance per Product Distance per Month

Product Month Layout A Layout B Layout A Layout B A 1000 70 70 70,000 70,000

B 2000 90 50 180,000 100,000

C 3000 30 30 90,000 90,000

D 1000 50 90 50,000 90,000

E 2000 30 30 60,000 60,000F 4000 30 30 120,000 120,000

Totals 570,000 530,000*


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Computer Packages

Heuristic, improvement algorithms.

CRAFT (Computerized Relative Allocation of FacilitiesTechniques) is the best known of the heuristicsapproaches; attempts to minimize materials-handlingcost by calculating cost, pair-wise interchangingdepartments, calculating more costs until a goodsolution is obtained.

ALDEP (Automated Layout Design Program) andCORELAP (Computerized Relationship LayoutPlanning) attempt to maximize a nearness ratingwithin the facility dimension constraints.

PREP (Plant Re-layout and Evaluation Package)

analyzes multilevel structures and is based on actualfootage traveled by materials-handling equipment.

05 facil ty design layout

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