2008年Nokia 生产过程控制全球培训教材(ppt 55) .pptVIP

本人有必威体育精装版名师培训视频6千集，管理文档8千份。想要的请联系QQ1589505898 Two Types of Processes All processes have: Natural (random) variability= due to common causes The Two Causes of Variation Common Causes: Causes that are implemented in the process due to the design of the process, and affect all outcomes of the process Identifying these types of causes requires methods such as Design of Experiment (DOE), etc. Special Causes: Causes that are not present in the process all the time and do not affect all outcomes, but arise because of specific circumstances Special causes can be identified using Statistical Process Control (SPC) Tolerances A tolerance is a allowed maximum variation of a dimension. Measurement Report Example of Capability Analysis Data For some critical dimensions we need to measure more than 1 part For capability data we usually measure 5 pcs 2 times/hour=100 pcs (but sampling plan needs to be made on the basis of production quantity, run duration and cycle time) Why Make Process Capability Studies The Nokia Process Verification Process Population versus Sample Population An entire group of objects that have been made or will be made containing a characteristic of interest The Normal Distribution Exercise 1: Sample Distributions 1. In Excel file Data exercise 1.xls you find 100 measurements being the result of a capability study. The specification for the dimension is 15,16?,01 2. How well does the sample population fit the specification, e.g. should we expect any parts outside spec? 3. Mention possible consequences of having a part outside spec . 4. Mention possible causes of variation for parts. 5. Calculate the sample mean and sample standard deviation for the 100 measurements. Use the average and stdev functions Excel. Defining Cp and Pp Defining Cpk and Ppk What is the Difference Between Cp and Cpk? Cp and Cpk Indices and Defects(both tails of the normal distribution) The Effects of Cpk and Cp on FFR Exercise 2: Cp and Cpk Calculate Cp and Cpk for the 100 meas