Overview: This course provides the attendees with the tools needed to understand and implement acceptance sampling. We explain the basis for sampling plans, the binomial distribution, and show how it helps us understand the sampling plan's performance using the operating characteristic (OC) curve. Participants will gain a solid understanding of how the OC curve is built, how to use it, and how to identify some of the most important points on the curve, including the AQL and RQL points.
The course also provides complete descriptions of three other important curves that help you understand a sampling plan. The average sample number (ASN) helps you predict the number of samples you will take. The average outgoing quality (AOQ) helps you foresee the results if you inspect rejected lots. The average total inspected (ATI) helps you calculate how many items you will inspect including rejected lots. Users of Z1.4 will want to understand how to set up sampling and select parameters such as AQL and Level. The course provides a complete description of Z1.4, showing the process from receiving the lot to selecting the sample size to making the accept/reject decision. We will discuss the following issues:
How to use the sampling tables to determine the sampling plan
Ways to avoid common errors and misunderstandings with the sampling tables
The difference between single, double, and multiple sampling plans
Why double sampling plans are the most economical choice
The reasons for the switching rules between normal, reduced, and tightened
The use of the switching rules to help improve your supplier management program
How the switching rules can help you reduce inspection cost
The c=0 plans are very popular, since they are based on the notion that everything in the sample should pass inspection. The course examines these plans using the curves described above. The OC curve, in these plans, has a different shape that can lead to problems. We will discuss the following issues:
How to use the c=0 plans instead of Z1.4 plans
The basis for the plans using the RQL point
The differences in the OC curves and why they can cause problems
How a change from Z1.4 to c=0 can impact your inventory and disrupt your suppliers
Why should you attend: Imagine this! Your company uses acceptance sampling in your manufacturing process and your manager asked to make sure it is cost effective. She also knows there is some risk associated with sampling, but she admits she doesn’t completely understand it. You now have a new assignment; assure your manager that you have good balance between risk and cost. The person who set up the system retired a few years ago and isn’t available to help. You have also heard about some new methods called c=0 or zero based acceptance.
How do you know how much your inspection system costs?
Are you inspecting too much, and wasting money?
Are you inspecting too little and incurring risk?
Do your current managers and supervisors understand how the system works?
Will your ISO 9001 registrar ask for justification of these statistical methods?
Should you start to use these c=0 plans you have heard about?
Can you improve the process?
Areas Covered in the Session:
With or without replacement
Simple or stratified sampling
The binomial distribution
Possible outcomes and Bernoulli trials
The binomial formula and what it means
The cumulative binomial
The AQL concept
The ideal OC curve
The practical OC curve
Reading risk off the OC curve
Special points on the practical OC curve
The AQL point
The IQL point
The RQL point
Characterizing sampling plans
Using rectifying inspection
The four important curves
The OC curve
The ASN curve
The AOQ curve
The ATI curve
Setting up the plan
Selecting the Level
Selecting the AQL
Knowing the lot size
Selecting single, double, or normal plans
Single sample plans
Double sample plans
Multiple sample plans
Cost analysis for single v. double plans
When to switch
Why reduced inspection lowers cost
How tightened inspection can help improve supplier performance
How they are matched to Z1.4 plans
The RQL point is the key
Making the curves cross at one point
How to employ switching rules
The OC curve
It is not the ideal curve
The difference in shape and the problems it causes
Consequences of moving from Z1.4 to c=0
Inventory management and stock-outs
Supplier management and performance metrics
Who Will Benefit: This seminar is designed for people in manufacturing who are involved in setting product specifications, setting up acceptance plans, performing acceptance activities, and supply chain management. Attendees should have knowledge of manufacturing process that includes acceptance activities such as incoming, in-process, and final acceptance. This typically includes: