Design of Products and Processes

Design of Product layout: Layout design for products can be classified into the following two methods

• Manual methods
• Computerized methods

 Manual Methods: Under this category there are some conventional methods like travel chart and Systematic Layout Planning (SLP). We will discuss Systematic Layout process:

 Systematic Layout Design Method (SLP): This is an organized approach to layout planning. This approach has been developed by Muther. It is clear that once the appropriate information is gathered, a flow analysis can be combined with an activity analysis to develop the relationship diagram. This space-relationship diagram is constructed by combining space considerations with the relationship diagram. Based on space relationship diagram, modifying considerations and practical limitations, a number of alternative layouts are designed and evaluated.

 Computerized methods: Under these methods the layout design procedures can be classified into constructive type algorithms and improvement type algorithms.

Constructive type algorithms are:

• Automated Layout Design Program (ALDEP)
• Computerized Relationship Layout Planning (CORELAP)

Improvement type algorithms are:

• Computerized Relative allocation of Facilities Technique (CRAFT)

We shall be discussing only Computerized Relative Allocation of Facilities Technique (CRAFT). This algorithm was originally developed by Armour and Buffa. Craft is more widely used than other computerized methods. It starts with an initial layout and improves the layout by interchanging the department’s pair wise so that the transportation cost is minimized.

CRAFT requirements

• Initial layout
• Flow data
• Cost per unit distance
• Total number of departments
• Fixed departments , their number and location
• Area of departments

CRAFT Procedures: The steps of CRAFT algorithm are summarized below

Step 1:

• Number of Department
• Number of interchangeable departments
• Initial layout
• Cost matrix
• Flow matrix
• Area of departments

 Step 2: Compare cetroids of departments in the present layout.

Step 3: Form distance matrix using the controls

Step 4: Given data on flow, distance and cost, compute the total handling cost of the present layout

Step 5: Find all the possible pair wise interchanges of departments based on common border of equal area criterion

Step 6: Find the pair of departments corresponding to minimum handling cost from among all possible pairs of interchanges.

Step 7: Interchange the selected pair of departments. Call this new layout