COMPUTERIZED PLANT LAYOUT

(Group – 8)

RUPESH SATISH NAPHADE (09mib034)R SANDEEP REDDY (09MIB046)SANKARANARAYANAN B (09MIB047)A.M.SARANYA (09MIB048)SHIVAM SETH (09MIB053)

Overview of Plant layout

• The basic objective of a plant layout is to ensure a smooth flow of work, material, and information through the system.

Requirements for effective layout• Minimize material handling costs.• Utilize space efficiently.• Utilize labor efficiently.• Eliminate bottlenecks.• Facilitate communication and interaction between workers and their

supervisors, or between workers and customers.• Reduce manufacturing cycle time and customer service time• Eliminate wasted or redundant movement.• Facilitate the entry, exit, and placement of material, products, and people.• Encourage proper maintenance activities.• Provide a visual control of operations or activities.• Provide flexibility to adapt to changing conditions.

Basic LayoutsThere are 4 basic types of layouts:• Process Layout• Product Layout• Fixed – position Layout• Group Technology Layout (Combination Layout)

Group Technology Layout• Definition of Group Technology

“Group technology is the technique of identifying and bringing together related or similar parts in a production process in order to utilize the inherent economy of flow production methods.”

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

Cntd….

• Group Technology layout is also called manufacturing cell layout. • Example:• A plant producing 10,000 part numbers may be able 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 in manufacturing efficiencies in the form of: • Reduced set-up, • Lower in-process inventories, • Better scheduling, • Improved tool control,• Standard process plan.

Concept• Many problems are similar, by grouping similar problems, a single

solution can be found to a set of problems, thus saving time and effort.

• A manufacturing philosophy in which similar parts are identified and grouped together to take advantage of their similarities in design and manufacturing.

• A technique for identifying and bringing together related or similar components in order to take advantage of their similarities in the production process.

Concept Design ManufacturingMany problems aresimilar

Similar Shapes SimilarManufacturingProcesses

Group SimilarProblems

Design Families Production Family

Single Solution ofProblems

One standard designplus minormodification

One standardprocess plan to afamily andmodification andextension

Flow-Line Layout• Applicable to both manufacturing and non manufacturing

operations.• Arrange machines and/or workers in accordance with the

sequence of operations for 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.

Cntd…• Disadvantages of flow-line layout• Lack of process flexibility.• Dependence of the whole on each part: a breakdown of one

machine or absence of enough operators to staff all work stations may stop the entire line.

• Worker fatigue: workers may become bored by the endless repetition of simple tasks.

• Lack of flexibility in timing: the product cannot flow through the line faster than the slowest task can be accomplished unless that task is performed at several stations.

• Large investments: special-purpose equipment and duplication is required to offset lack of flexibility in timing.

Computerized Layout Planning

• Focus on how computers can aid the facility layout process.• Designer must interact with multiple design databases and

provide the integration between them to translate information and ensure consistency.

• Under this method, the layout design procedures can be classified into constructive type and algorithms and improvement type algorithms.

- Competitive type algorithms: Automated Layout Design Program (ALDEP)

Computerized Relationship Layout Planning (CORELAP)

- Improvement type Algorithms: Computerized Relative Allocation of Facilities Technique (CRAFT)

Computerized Layout Planning

• Key element of computerized layout planning is the representation and manipulation of these three types of information.

• Information in layout planning• Numeric information• Space required for an activity• Total flow between two activities

• Logic information • Preferences of the designer, i.e., activity relationship chart

• Graphical information• Drawing of the block plan

CRAFT

• Computerized Relative Allocation of Facilities Technique

• Developed by Armour and Buffa

• Most widely used than ALDEP and CORELAP

• The result given is not optimum in terms of minimum cost ,but

close to optimum in majority of applications

CRAFT procedure

1. Initial layout

2. Flow data

3. Cost per unit distance

4. Fixed depatrments

5. Area of department

ExamplePresent layout of the departments

STEP 1Cost matrix -Cij

The values in above matrix represents cost per unit distance from department to department

Flow Matrix - Fij

The values in above matrix flow of items in terms of number of trips in given time

Area of department - Aij

STEP 2Centorid

•Find The centroid of each department in the initial layout.

•Consider left side of layout as Y axis and bottom as X axis

(X1,Y1) = 2,6(X2,Y2) = 2,2(X3,Y3) = 7,2(X4,y4) = 8,6(X5,Y5) = 5,6

STEP 3Distance -dij

•Find Distance between the two departments by formula

dij = |Xi-Xj|+|Yi-Yj|

We get the distances as shown below

STEP 4Total Cost - TCij

Total cost = ∑∑fij*dij*cij

STEP 5Departmental interchanges

Consider various departmental interchanges for improvement

Interchanges possible are given below –

• Departments having common border

• Departments having equal area

For each interchnage the associated total cost matrix is

calculated

Consider interchange between 1 and 2

New centorid after interchange will be (X1,Y1) = 2,2(X2,Y2) = 2,6(X3,Y3) = 7,2(X4,y4) = 8,6(X5,Y5) = 5,6

New Distance matrix is as shown below

Total Cost = 205

Summary of total cost due to interchange

Step 6 – Interchange which gives lowest handling cost is

selected for actual interchange in layout.

Step 7 – The cost is compared with the cost of present layout

Here the handling cost is 163 which is less than present cost of

205

Hence it is accepted

Step 8Final layout

ALDEP(Automated Layout Design Program)

It is a construction type algorithm. This algorithm uses the basic data on facilities and build a design by successively placing the departments in the layout and scores is computed. This algorithm is repeated for a prespecified number of times and the best is selected out of it.

Basic data required for algorithm

• Number of departments in the layout• Area of each department• Length and width of layout• Rel-chart• Minimum department preference value(MDP)• Sweep width• Number of iterations to be carried

PROBLEMS

1) Number of departments in the layout=72) Area of departments

DEPARTMENT FUNCTIONS AREA(sq.m)

1 receiving 12000

2 milling 8000

3 press 6000

4 screw mc 12000

5 assembly 8000

6 painting 12000

7 shipping 12000

TOTAL 70000

3) Relationship chart

FROM

1 NIL

2 E NIL

3 O U NIL4 I E U NIL

5 O I U I NIL

6 U I O U A NIL

7 U U U U I E NIL

TO 1 2 3 4 5 6 7

4) Minimum department preference value=I=4.5) Sweep width=2.6) Number of iterations to be performed=2.

SOLUTION Area of the department

DEPARTMENT AREA(sq.m) NO OF SQUARES1 12000 302 8000 203 6000 154 12000 305 8000 206 12000 307 12000 30

TOTAL 70000 175

Assume one square of department =400sq.m.The total scaled area is 175sq.unitsLength and width of proposed layout are exactlya) 10m*17.5m=175sq.mOr we can choose approximately 180sq.m12m*15m=180sq.m

1) Randomly select a department to entre in to layout first. Here let us consider 4 th dep which is 30 sq.units.

4 4

4 4

4 4

4 4

4 4

4 4

4 4

4 4

4 4

4 4 4 4

4 4 4 4

4 4 4 4

2) Now classify the unselected dept base on the Rel-chart in to List A & List B , where A contains dept which have relation value less than I in relation to the last selected dept and B contains dept which have value greater than I with comparison with the last selected dept. unselected dept are 1,2,3,5,6,7.List A (3, 6,7)List B (1,2,5)

3) Select the dept from the list B with the max REL value in relation to 4th dept, so dept 2 is selecedArea of dept 2 is 20 sq.units

4 4 2 2 2 2

4 4 2 2

4 4 2 2

4 4 2 2

4 4 2 2

4 4 2 2

4 4 2 2

4 4 2 2

4 4 2 2

4 4 4 4

4 4 4 4

4 4 4 4

4) Now the last selected dept is 2nd , find the REL value for unselected dept with the 2nd dept. now the unselected dept are 1,3,5,6,7.List A (3,7)List B (1,5,6)Here 1st dept has the max REL value with 2nd dept , so we select 1st dept which has the area of 30 sq units.

4 4 2 2 2 2

4 4 2 2 1 1

4 4 2 2 1 1

4 4 2 2 1 1

4 4 2 2 1 1

4 4 2 2 1 1

4 4 2 2 1 1

4 4 2 2 1 1

4 4 2 2 1 1 1 1

4 4 4 4 1 1 1 1

4 4 4 4 1 1 1 1

4 4 4 4 1 1 1 1

5) Similllarly for all the other dept it needs to be filled in relation with the last selected dept. after selecting all the other dept the layout will be

4 4 2 2 2 2 6 6 6 6 7 7 7 7 0

4 4 2 2 1 1 6 6 6 6 7 7 7 7 0

4 4 2 2 1 1 6 6 6 6 7 7 7 7 0

4 4 2 2 1 1 6 6 6 6 7 7 7 7 0

4 4 2 2 1 1 6 6 6 6 7 7 7 7 0

4 4 2 2 1 1 6 6 6 6 7 7 7 7 3

4 4 2 2 1 1 6 6 6 6 7 7 7 7 3

4 4 2 2 1 1 6 6 5 5 5 5 7 7 3

4 4 2 2 1 1 1 1 5 5 5 5 3 3 3

4 4 4 4 1 1 1 1 5 5 5 5 3 3 3

4 4 4 4 1 1 1 1 5 5 5 5 3 3 3

4 4 4 4 1 1 1 1 5 5 5 5 3 3 3

Where in the above layout “0” denotes the empty space for further use.6) Finally the score of the layout is computed, the score is the sum of the Rel values of various neighboring pairs of dept in the layout.

NEIGHBOURING PAIRS

OF DEPTREL GRADE REL VALUE

4-2 E 16

4-1 I 4

2-1 E 16

2-6 I 4

1-6 U 0

1-5 O 1

6-7 E 16

5-6 A 64

5-7 I 4

5-3 U O

7-3 U O

TOTAL 125

The score based on 2 way relationship is 250 ie(2*125)Since this is the first layout treat this as the best layout and store the corresponding score.Increment the iteration number I=I+1=2. if I<=N , repeat the same process again.After doing it check whether the second iteration layout is lesser than the 250 then the 1st layout will be printed as the best one.

Computerized Relationship Layout Planning(CORELAP)• Developed by R.C.Lee based upon Muther’s algorithm

• INPUT REQUIREMENTS: 1. Number of departments and their area2. Closeness relationship as given by REL chart 3. Weighted ratings for REL chart entries

CORELAP(contd..)• The most critical department is placed first at the center of the

layout• The highest closeness relationship with the department

already placed are consecutively placed. • The final layout may not be in rectangular in shape and little

modification is required to suit the situation

CORELAP(contd…)

CORELAP Algorithm1. Defining basic data2. Determination of placement order 3. Placement of departments in the layout4. finding the total score of the layout