This Minitab worksheet shows a portion of the central composite design. The steps that will be followed for the central composite design (CCD) are presented in Figure 2. In this study, design expert (Version: 8.0.7.1) is used as optimization software.
The engineer creates a central composite design to analyze the curvature and find the best factor settings. Central composite design under RSM is normally performed either by using design expert software or Minitab. First, the engineer performs a fractional factorial design, and identifies the important factors (temperature, pressure, cooling rate) and determines that curvature is present in the data. Once you have collected your data, use Analyze Response Surface Design to analyze the data.įor example, an engineer wants to analyze the injection-molding process for a plastic part. When you create a design, Minitab stores the design information in the worksheet, which shows the order in which data should be collected. For more information, go to What are response surface designs, central composite designs, and Box-Behnken designs?. Usually, you use a central composite design after you have conducted a factorial or fractional factorial experiment and have identified the most important factors in your process. Central composite designs enable you to build on factorial or fractional factorial design by adding center points, augmented with axial points that let you estimate curvature. Use Create Response Surface Design (Central Composite) to create a designed experiment for 2−10 factors to model curvature in your data and identify factor settings that optimize the response. In addition to this central composite design (CCD) with the help of MINITAB version 15 Software was utilized to optimize the process variables viz., pH and temperature affecting the enzyme activity upon immobilization on AuNPs.