Mar 22 2017
Saturation In Manufacturing Versus Service
In Capacity Planning For 1st Responders, we considered the problem of dimensioning a group so that there is at least one member available when needed. Not all service groups, however, are expected to respond immediately to all customers. Most, from supermarket check stands and airport check-in counters to clinics for non-emergency health care, allow some amount of queueing, giving rise to the question of how long the queues become when the servers get busy.
![](https://i0.wp.com/michelbaudin.com/wp-content/uploads/2017/03/Patients-waiting-in-US-Emergency-Room.jpg?resize=150%2C86&ssl=1)
At one point in his latest book, Andy and Me And The Hospital, Pascal Dennis writes that the average number of patients in an emergency room is inversely proportional to the availability of the doctors. The busier the doctors are, the more dramatic the effect. For example, if they go from being busy 98% of the time to 99%, their availability drop by half from 2% to 1%, and the mean number of patients doubles. Conversely, any improvement in emergency room procedures that, to provide the same service, reduces the doctors’ utilization from 99% to 98%, which cuts the mean number of patients — and their mean waiting time — in half.
Jul 31 2017
Acceptance Sampling In The Age Of Low PPM Defectives
Today, some automotive parts manufacturers are able to deliver one million consecutive units without a single defective, and pondering quality management practices appropriate for this level of performance is not idle speculation. Of course, it is only achieved by outstanding suppliers using mature processes in mature industries.
You cannot expect it during new product introduction or in high-technology industries where, if your processes are mature, your products are obsolete. While still taught as part of the quality curriculum, acceptance sampling has been criticized by authors like W. E. Deming and is not part of the Lean approach to quality.
For qualified items from suppliers you trust, you accept shipments with no inspection; for new items or suppliers you do not trust, you inspect 100% of incoming units until the situation improves. Let us examine both what the math tells us about this and possible management actions, with the help of 21st century IT.
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By Michel Baudin • Laws of nature • 6 • Tags: Acceptance Sampling, DPMO, Lean Quality, Six Sigma, SPC