1 / 14

CHEE418/801

CHEE418/801. Strategies for Process Investigations Kim McAuley Fall 2012. Module 1 Outline. Why do we need to investigate process behaviour? How do we investigate process behaviour? What are we going to look at in this course? Why do we need a statistical framework anyway?

lareina-mccarty
Download Presentation

CHEE418/801

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHEE418/801 Strategies for Process Investigations Kim McAuley Fall 2012

  2. Module 1 Outline • Why do we need to investigate process behaviour? • How do we investigate process behaviour? • What are we going to look at in this course? • Why do we need a statistical framework anyway? • What are the roles for statistical methods? • What do I need to remember from my first statistics course? CHEE418/801 – K. McAuley

  3. Example Twin-screw extruder for grafting functional groups on polyethylene Why graft? • Enhance product properties • Improve product value $$$ CHEE418/801 - K McAuley

  4. Twin Screw Extruder CHEE418/801 – K. McAuley

  5. Twin-Screw Extruder • Reactions • Free radical initiator decomposes and reacts with polymer backbone • Backbone radicals react with additive molecules to cause grafting • Side reactions • Can we find a better set of operating conditions to improve grafting efficiency? • % of additive that is grafted onto polymer • What factors could affect grafting efficiency? • How could we find out? CHEE418/801 - K. McAuley

  6. Improving the extruder grafting efficiency • Run experiments, collect data • Now it’s time to analyze the results • Goal – identify those operating variables (factors) having a significant effect on grafting efficiency • How can we characterize the effect of operating variables on grafting efficiency? • Graphically • Quantitatively • We might want to RANK the operating variables from most effective to least, and understand the SIZE of their effects • Then what? CHEE418/801 – K. McAuley

  7. How much variability is there in our experiments? • Can we tell this from our experimental results? • How will this variability carry through into our calculations? • How can we factor in the variability into our decisions about which operating variables are important? CHEE418/801 - K. McAuley

  8. Why do we care about product quality? • American Society for Quality Control • totality of features and characteristics of a product or service that bear on its ability to satisfy given needs • Deming • uniformity about target • Juran • fitness for use • Taguchi • loss imparted to society from the time a product is shipped CHEE418/801 – K. McAuley

  9. Continuous Improvement • In addition to monitoring current quality, strive to improve the quality of the process operation and product • Concerted effort involving all participants in the organization • operators, management, supervisors, unit engineers, designers, administrative support staff, … • Requires knowledge of the effects of factors influencing process and product performance CHEE418/801 - K. McAuley

  10. The Iterative Nature of Process Investigations Identify Objectives Design Experiments Analyze Data Collect Data CHEE418/801 - K. McAuley

  11. Why do we need statistical methods? Processes are inherently subject to variation, which appears in measurements and propogates through any computations made with the measurements Need tools that: 1) can characterize this variability 2) accommodate variability in analysis and computations CHEE418/801 – K. McAuley

  12. Where does variability come from? CHEE418/801 - K. McAuley

  13. What do you need to remember from your first Probability and Stats course? Characterizing Variability Patterns • random variables • probability distributions - density and distribution fns. • expected value • variance, standard deviation, mean • graphical methods - histograms, box plots • the Normal probability distribution • statistical independence CHEE418/801 – K. McAuley

  14. What do you need to remember from your first Probability and Stats course? Estimating Characteristics from Data • the notion of a statistic with associated probability distribution • sample average, sample variance and standard devn. • Standard Normal, Chi-squared and F-distributions • degrees of freedom • linear regression Making Inferences • hypothesis tests • confidence limits • comparison against reference distribution What did you learn to make inferences about? CHEE418/801 - K. McAuley

More Related