hi, i hope toyota isn't listening to this. they never end their search for 'quality', and that's why i'll never buy another brand. phil -----Original Message----- From: Brian Ellis [mailto:[log in to unmask]] Sent: Tuesday, January 08, 2002 8:53 AM To: [log in to unmask] Subject: Re: [TN] A SERIOUS QUALITY QUESTION Aren't we missing the point of quality control? Yes, we need consistent quality, but it must be just sufficiently good that it meets the requirements at minimum cost. Over-engineering, whether it be quality, a product or a process is a sin, n'est-ce-pas? In past lives, I've much used Taguchi orthogonal array experiments to determine the optimum between quality and cost. I even wrote a software to do it. With only 8 experiments, you can optimise 7 variables, provided you confirm the result with a single further experiment. It's as easy as falling off a log. And you can see the effect of compromises, without hundreds of experiments that the conventional approach would require. Taguchi developed 4 basic concepts of quality: 1. Quality should be designed into the product from the start, not by inspection and screening. 2. Quality is best achieved by minimising the deviation from the target, not a failure to conform to specifications. 3. Quality should not be based on the performance, features or characteristics of the product. 4. The cost of quality should be measured as a function of product performance variation and the losses measured system-wide. These were based on the philosophy of: Quality is the loss imparted to society from the time the product is shipped This approach seems to put the cart before the horse but if you read his work carefully, you will see the sense in it. I could say that Taguchi has been my virtual mentor for well over a decade. Do you want to know more? There is an excellent treatise on this philosophy at http://kernow.curtin.edu.au/www/Taguchi/cae204.htm , assembled by a group of students at an Oz University, one of them being Japanese who was able to do the final editing with reference to the original publications. This is as serious as I'll go on the matter, but I'm very serious indeed about the quality of Maître Taguchi's work. Brian --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To recieve ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To recieve ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------