Case Studies and White Papers
Graphical Selection of Effects in General Factorials
This presentation details and demonstrates how to plot effects from general factorials, for example a 3x4x4, on a half-normal plot. This makes selection easy and more precise by it being a graphical method. Previously the half-normal plot of effects, developed by Cuthbert Daniel, was restricted to two-level factorials.
This article starts with the basics on RSM before introducing two enhancements that focus on robust operating conditions: Modeling the process variance as a function of the input factors and Propagation of error(POE) transmitted from input factor variation. It discusses how to find the find the flats high plateaus for maximum yield and broad valleys that minimize defects. Proceeding from International SEMATECH Manufacturing Initiative (ISMI) Symposium on Manufacturing Effectiveness.
This case study details how the Intertape Polymer Group (IPG) used Design of Experiments (DOE) to solve an adhesive tape production problem.
Response Surface Methods for Peak Process Performance
This is the third article of a series on design of experiments (DOE). The first publication provided tools for process breakthroughs via two-level factorial designs. The second article illustrated how to re-formulate rubbers or plastics using powerful statistical methods for mixture design and analysis. Via two case studies, the author now brings the focus back to process improvement. The key is in-depth DOE aimed at producing statistically-validated predictive models. Response maps made from these models point the way to pinnacles of process performance--sweet spots at high yield of in-specification products made at lowest possible cost.
This article offers 10 tips for avoiding the most common designed experiment mistakes. It is derived from Jeff Hybarger's article in the December 2006 Stat-Teaser newsletter.
This article deals with thorny issues that confront every experimenter, i.e., how to handle individual results that do not appear to fit with the rest of the data - damaging outliers and/or a need for transformation. The trick is to maintain a reasonable balance between two types of errors: (1) deleting data that very only due to common causes, thus introducing bias to the conclusions. (2) not detecting true outliers that occur due to special causes. Such outliers can obscure real effects or lead to false conclusions. Furthermore, an opportunity may be lost to learn about preventable causes for failure or reproducible conditions leading to break-through improvements (making discoveries more or less by accident).
This article describes a methodological study focused on evaluating the application of MDOE to future operational codes in a rapid and low-cost way to assess the effects of cavity geometry uncertainty.
This article details the advantages of design of experiments (DOE) over the OFAT (changing only one factor at a time) approach to experimentation. By varying factors at two levels each, but simultaneously rather than one at a time, experimenters can uncover important interactions.
This mini-paper, provided on pages 5-8 in the publication via the link above*, addresses concerns about mixture designs coming up short on power. *(Manuscript available under Download link below.)
EDM fast hole drilling is one of the most important variations of electrical discharge machining. The process plays an important role in the aerospace industry as it is one of the few that can be applied to the drilling of precision small holes in a number of parts, including turbine blades. One of the most important factors affecting the speed of EDM fast hole drilling is the high pressure dielectric fluid, which is usually supplied to the gap through the bore to tubular electrodes. Thus, it can be expected that the bore size and geometry have a great impact on the process performance. However, there has not been much research on this topic. By employing statistical methods to optimise the process performance, this work shows that drilling time and electrode wear can decrease 165% and 25% respectively, depending on the type of electrode geometry used.