What Is Process Capability?

In the process of managing the state, this process has the ability to achieve quality, which is called process capability. The quality characteristics of products measured in a process that accurately maintains the conditions or standards of operations and is economically sound and stable in terms of counts are usually or sometimes only expressed as 6.

Process Capability

In the process of managing the state, this process has the ability to achieve quality, which is called process capability. The quality characteristics of products measured in a process that accurately maintains the conditions or standards of operations and is economically sound and stable in terms of counts are usually or sometimes only expressed as 6.

Chinese name

Process Capability

Foreign name

process capability

Express

Ability to meet product specifications

Recorded as

6

Process capability indices (and): Process capability indices are simple values used to indicate the ability of a process to meet product specifications. The value of the indicator can be regarded as the potential capability of the process, that is, the ability of the process to meet the specifications when the average value of the process can be adjusted to the specification center or the target value. The value of the indicator is similar to the indicator, but the process average is taken into account.

Process capability analysis: Statistical techniques can be used to assist development activities before manufacturing, process variability during product production cycles

Process capability: The so-called process capability is the economic amplitude of normal fluctuations in the quality of processed products under the state of statistical control, which is usually 6 times the distribution of quality characteristics.

There are two main reasons for performing a process capability analysis:

We need to know the controllability of the number of baselines that process metrics can provide;

· Because our measurement plan is still quite "immature", we need to evaluate the process measurement baseline to decide whether to change it to reflect improvements in process capabilities. Based on the quantitative indicators of process capability, we can relax or narrow the control conditions of the baseline accordingly.

Process capability refers to the actual processing capability of the process in the normal state of 5M1E, which can stably produce qualified products. Process capability depends on the accuracy of machine equipment, materials, processes, process equipment, the quality of workers' work, and other technical conditions. The process capability index is expressed by Cp and Cpk.

Case 1: Key indicators of a certain process of a company?-The control chart of the pulling force parameters is as follows, we analyze the following process capabilities: Cpk = Min [(USL- Mu) / 3s, (Mu-LSL) / 3s]

Process capability index

(1) Process capability index measurement

Direct assay

Some characteristics of the equipment or device used in the process are directly measured to obtain relevant parameters. For example, check the accuracy of the machine tool regularly so that it can maintain good processing performance.

By measuring the products produced by the process, and calculating and analyzing the process capabilities based on their changes. The measurement of product quality characteristic values not only obtains the quality of the product itself, but also changes in product quality characteristic values also reflect changes in process quality, and it is often feasible in actual production processes to infer process quality through product quality. . Calculation

Through analysis of operational and management errors to determine whether the process capacity is sufficient. The measurement of "software" such as the ability of operators is often difficult to measure with instruments, but the analysis of all types and quantities of errors can be used to infer whether the process capacity is sufficient.

• Computational Process Capability

For preliminary estimates of process capability, historical data should be used, but data points related to special reasons should be excluded;

When formal study of process capability, new data should be used, preferably 25 or more subgroups of periods, and all points are under statistical control. The p-values of these consecutive controlled subgroups are a better estimate of the current capabilities of the process.

• Assess process capability

The process capability just calculated reflects the current level of performance of the process production and possibly expected production. As long as the process remains controlled and does not experience any fundamental changes in performance, the process will be able to operate at its current level. From one period to another, the measured percentage of nonconforming product will vary between the control limits, but excluding any changes in the process, or allowing periods beyond control, the average of the percentage of qualified products will tend to Yu stable.

• Improve process capability

Once the process appears to be in a state of statistical control, the average level of nonconformity maintained by the process reflects the cause of the system's deteriorationprocess capability. Analytical methods for diagnosing deterioration of special causes in operation are not suitable for diagnosing deterioration of common causes affecting the system. Management measures must be taken directly on the system itself, otherwise process capability cannot be improved. It is necessary to use long-term problem-solving methods to correct the causes of long-term nonconformities.

You can use problem-solving techniques such as permutation chart analysis and causal analysis charts, but if it is difficult to understand the problem using only count-type data control charts, analysis with the help of metrological data control charts will help solve the problem.