Computerized Plant Layout
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Transcript of Computerized Plant Layout
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