Nov 29 2023
Online forums do not often discuss quality fundamentals like characteristics and tolerances. You find arguments about process capability, but the requirements for process capability are taken as given. Tolerances on characteristics are objectives that production is expected to meet, and deserve an exploration of what they mean and how they are set.
Nov 13 2023
Within the quality profession, a capable process is one with a high C_{p_k}. In the field, it is not quite so simple. My colleague Joerg Muenzing recently shared concerns about the process capability indices:
“Many manufacturers that I know struggle with incapable processes. Intellectually, people understand the concept of capability, but are unable to effectively apply it to an entire process. A single-figure measure for the entire chain would be ideal to better understand and manage it. The challenge is that the chain consists of processes with measurable characteristics, like thickness, substitute characteristics, like leak current to infer dryness, and also visual inspection results like blemishes or scratches.
They know that C_{p_k} < 1 is bad, and scrap shrinks the bottom line, but not much more. At the same time, customers like large Automotive OEMs demand from their suppliers a C_{p_k} > 1.33 for manual and “uncritical” characteristics, and C_{p_k} >1.66 or even >2.00 for critical characteristics.
What would be useful without being ‘too wrong’?”
Let’s take a closer look.
Sep 23 2023
Data visualization is not just the art of presenting data to an audience. Upstream from this, you use visualizations in data cleaning to identify defective points, and in exploratory analysis, to identify patterns of interest. Then, you validate these patterns with a more formal analysis. Once confident that you have findings of value to communicate, you worry about making a compelling presentation.
Nick Desbarats and I had a long exchange on LinkedIn prompted by his article Connected Scatterplots Make Me Feel Dumb in Nightingale, the Data Visualization Society journal, on 8/29/2023. What he called Connected Scatterplot is what I call orbit charts, and I have found them helpful, particularly in analysis.
Jul 15 2023
Let us focus on what Generative AI does generate, speaking exclusively from personal experience. Generative AI is the generic term for systems like ChatGPT, Google’s Bard, DALL-E, or MidJourney, that generate text, images, or other media in response to prompts. All sorts of news sources report it as a revolutionary technology poised to dramatically change how we work and communicate.
May 13 2023
Even on LinkedIn, you still see posts and comments asserting that the COVID-19 vaccines aren’t “real” and alleging that they do more harm than good. This is usually based on articles of questionable value and the author’s brother-in-law catching COVID-19 while vaccinated. Public health, however, warrants serious research and is not a matter of anecdotes.
The real question is whether the administration of these vaccines to large populations was effective in curbing the pandemic and saving lives. Today, we can answer yes to some of these questions with simple methods applied to data from the US government. Specifically, we can analyze US CDC and census data on state-by-state Excess Deaths and fractions of the population vaccinated for 2021 and 2022. The results are obvious but, sometimes, the obvious needs belaboring.
Jan 12 2024
Gaussian (Normal) Distributions In Science
The Gaussian – also known as “Normal” – distribution is used and abused in many domains. In Manufacturing, this includes quality assurance, supply-chain management, and human resources. This is the first in a series of posts aimed at understanding the range of applicability of this tool.
Googling uses of the normal distribution produces nearly 1 million results. Yet the top ones all ignore science, even when you narrow the query to physics, and this post attempts to remedy this. For example, the Gaussian distribution plays a central role in modeling Brownian motion, diffusion processes, heat transfer by conduction, the measurement of star positions, and the theory of gases.
These matter not just because the models are useful but also because they anchor this abstraction in physical phenomena that we can experience with no more equipment than is used in a Middle School science project. This post will not help you solve a shop floor problem by the end of the day, but I hope you will find it nonetheless enlightening.
Continue reading…
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By Michel Baudin • Laws of nature • 4 • Tags: Brownian motion, Diffusion, gaussian, Heat transfer, Normal distribution, Theory of Gases