Computerized layout design methods use algorithms to represent space requirements, activity relationships, and graphical information to generate layouts. There are two main algorithm types: constructive algorithms which build layouts and improvement algorithms which optimize initial layouts. Examples of constructive algorithms are ALDEP and CORELAP, while CRAFT is an improvement algorithm that starts with an initial layout and iteratively exchanges departments to reduce transportation costs until no further improvements are possible. These computerized methods require inputs like area requirements, relationship charts, and flow data to systematically generate optimized layouts.
1. COMPUTERIZED
METHODS OF LAYOUT
DESIGN
•Plant layout is of fundamental
importance of the arrangement and
allocation of internal plant areas an
essential and frequent operation for
large industrial installations.
•First step toward design automation
has been completed with advent of
computer aided drafting.
2. COMPUTERIZED METHODS OF
LAYOUT DESIGN
• The key element of Computerized Layout planning is the
representation & manipulation of the following three
types of information:
1. Numeric information: Space required for an activity, total flow
b/w two activities
2. Logic information: Preferences of the designer, i.e., the
activity relationship chart
3. Graphical information: Drawing of the block plan
3. COMPUTERIZED METHODS OF
LAYOUT DESIGN
• In Computerized methods of Layout Design, we have two
types ofAlgorithms, i.e:
1. ConstructiveType Algorithm
2. ImprovementType Algorithm
4. COMPUTERIZED METHODS OF
LAYOUT DESIGN
• Constructive Algorithms are of following types:
1. Automated Layout Design Program (ALDEP)
2. Computerized Relationship Planning (CORELAP)
5. AUTOMATED LAYOUT DESIGN
PROGRAM (ALDEP)
• ALDEP is basically a construction algorithm, but it can
also be used to evaluate layouts
• It uses basic data on facilities & builds a layout by
successively placing the layout using relationship
information b/w the departments
6. AUTOMATED LAYOUT DESIGN
PROGRAM (ALDEP)
Basic Inputs to ALDEP:
1. Length & width of facility
2. Area of each department
3. Minimum Closeness Preference (MCP)Value
4. Relationship chart showing the closeness rating
5. Location & size of any restricted area
7. AUTOMATED LAYOUT DESIGN
PROGRAM (ALDEP)…
Procedure Adapted for using ALDEP :
Step#01: Input the following
1. Length & width of facility
2. Area of each department
3. Minimum Closeness Preference (MCP)Value
4. Sweep width
5. Relationship chart showing the closeness rating
6. Location & size of any restricted area
8. AUTOMATED LAYOUT DESIGN
PROGRAM (ALDEP)…
Step#2: One department is selected randomly & placed in the
layout
Step#3: In this step, the algorithm uses minimum closeness
required b/w departments for the selection of departments to
be placed with an earlier placed department.
Select the department having maximum closeness rating. If
there is no department having minimum closeness preference
then any dept that remains to be placed is selected
9. AUTOMATED LAYOUT DESIGN
PROGRAM (ALDEP)…
Step#4: If all the departments are placed in the layout, go
to step#5. else go to step#3
Step#5: Compute the total score of the layout
Step#6: If the total score required is acceptable score, then
go to step#7, else go to step#2
Step#7: Print the current layout & the corresponding score
10. COMPUTERIZED RELATIONSHIP
LAYOUT PLANNING (CORELAP)
• CORELAP constructs layouts by locating rectangular
shaped departments
• The relationship chart provides the basis for the order in
which different departments are placed
• The input requirements of CORELAP consists of:
1. Relationship chart with weights for the depts
2. Number & area of departments
11. COMPUTERIZED RELATIONSHIP
LAYOUT PLANNING (CORELAP)
The Procedure adopted for using CORELAP:
1. Defining input data
2. Determination of placement sequence
3. Designing of layout
4. Calculating the total score of layout
12. ImprovementType Algorithm
• The most famous type in Improvement types Algorithms is;
1. Computerized Relative Allocation of FacilitiesTechnique
(CRAFT).
13. COMPUTERIZED RELATIVE ALLOCATION OF
FACILITIESTECHNIQUE (CRAFT)
• CRAFT is more popular than the other computer based layout
procedures.
• It is improvement algorithm & starts with an initial layout &
proceeds to improve the layout by interchanging the
departments pair wise to reduce the total material
transportation cost
• It does not give the Optimal Layout; but the results are good
& near optimal, which can be later corrected to suit the need
of the layout planner
14. COMPUTERIZED RELATIVE
ALLOCATION OF FACILITIES
TECHNIQUE (CRAFT)..
Features of CRAFT:
1. It attempts to minimize transportation cost, where
Transportation cost = flow x distance x unit cost
2. It Requires assumptions that:
(1) move cost are independent of the
equipment utilization &
(2) move costs are linearly related to the
length of the move
15. COMPUTERIZED RELATIVE
ALLOCATION OF FACILITIES
TECHNIQUE (CRAFT)..
Features of CRAFT:
3. Distance matrix used is the rectilinear distance b/w
department centroids
4. CRAFT being a path-oriented method, the final layout
is dependent on the initial layout.Therefore, a number
of initial layouts should be used as input to the CRAFT
5. CRAFT allows the use of dummy departments to
represent fixed areas in the layout
16. COMPUTERIZED RELATIVE
ALLOCATION OF FACILITIES
TECHNIQUE (CRAFT)..
Input Requirements of CRAFT:
CRAFT input requirements are as follows:
1. Initial Layout
2. Flow Data
3. Cost per unit distance
4. Total number of departments
5. Fixed departments & their location
6. Area of departments
17. COMPUTERIZED RELATIVE
ALLOCATION OF FACILITIES
TECHNIQUE (CRAFT)..
Procedure adopted for using CRAFT:
1. Determine the department centroids
2. Calculate rectilinear distance b/w centroids
3. Calculate transportation cost for the layout
4. Consider department exchanges of either equal area
departments or of departments sharing common border
5. Determine transportation cost of each department
interchange
18. COMPUTERIZED RELATIVE
ALLOCATION OF FACILITIES
TECHNIQUE (CRAFT)..
Procedure adopted for using CRAFT:
6. Select & implement the departmental interchange that
offers the greatest reduction in transportation cost
7. Repeat the procedure for the new layout until no
interchange is able to reduce the transportation cost
19. COMPUTERIZED RELATIVE
ALLOCATION OF FACILITIES
TECHNIQUE (CRAFT)..
Major Disadvantage of Using CRAFT:
1. Because the basis is the cost of materials handling, only
production departments are considered.
2. An initial idea of the layout is required.Therefore the
technique only applies to the modification of an
existing layout or new layouts where the outline shape
is known
20. COMPUTERIZED RELATIVE
ALLOCATION OF FACILITIES
TECHNIQUE (CRAFT)
Major Disadvantage of Using CRAFT:
3. The Distance b/w the departments is taken as straight lines
where as in practice movement is usually rectangular along
orthogonal lines
21. Thank you
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