INTRODUCTION

INTRODUCTION

1. Strategy of Experimentation

   • Definition
     • Exp.-->Test/Series of tests which purposeful changes are made to the input variables of process to observe & identify reasons for changes observed in output respone
     • Process -->combination of machines, methods, people & other sources that transform some input into output that has one/more observable response
   • Objective
     • To develop robust process, process affected minimally by external sources of variability
   • Approach to planning & conducting exp.
     • Best guess approach
     • One factor at a time
     • Factorial

2. Typical Applications of Experimental Designs

   • Advantages of early application in process development
     • Improve process yield
     • Reduced development time
     • Reduced overall cost
     • Reduced variability & closer conformance to target requirement
   • Application in engineering design
     • Evaluation of material alternatives
     • Advantages
       • Products easier to produce
       • Lower product cost
       • Shorter product design & development time

3. Basic Principles

   • Replication
     • Repetition of basic exp.
     • Obtain estimation of experimental error
     • More precise sample mean determination
   • Randomization
     • Averaging out effect of extraneous factors
   • Blocking
     • To improve precision with which comparisons among factors are made
     • Set of homogenous experimental condition
     • To reduce variability between batches of raw materials

4. Guidelines for Designing Experiment

   • 1. Recognition of & statement of problem
   • 2. Choices of factors, levels & ranges
   • 3. Selection of response variable
   • 5. Performing exp.
   • 6. Statistical analysis of data
   • 7. Conclusion & recommendations
   • 4. Choice of experimental design