Figures 3.2 and 3.3 are examples of X and R charts showing the solder paste height deposition process for a surface mount technology (SMT) process. Several observations can be made from examining thes...

The control limits are set to three times standard deviation of the sample distribution (s). s can be calculated from a the population standard deviation using the factor d2 according to the central l...

Example 3.1In this example, a critical dimension for a part is measured as it is being inspected in a machining operation. To set up the control chart, four measurements were taken every day for 25 su...

The control limits for the control charts are calculated using the following formulas and Table 3.1 for control chart factors. The control chart factors were designated with variables such as A2, Ds, ...

Variable processes are those in which direct measurements can be made of the quality characteristic in a periodic or daily sample. The daily samples are then compared with a historical record to see i...

Control charts have been traditionally used as the method of determining the performance of manufacturing processes over time by the statistical characterization of a measured parameter that is depend...

Chi-square(X 2)  tests can be used determine whether a set of data can be adequately modeled by a specified distribution. The chi-square test divides the data into nonoverlapping intervals calls ...

Using graph paper, spreadsheets, or statistically based software, measurement data from randomly selected samples of parts can be quickly checked for normality as follows: 1. Randomly select a nu...