Example 2: - The training room temperature during the training must be kept between 18 degrees Celsius and 26 degrees Celsius. Take the example of a motorcycle driving in the same lane going in … Cp: Process Capability Index Cpk: Process capability considering location within the upper and lower specification limits or tolerance Cpk is the smaller of the Cpk u or Cpk L C pkU = (USL - X) 3σ C p = (USL - LSL) 6σ C pkL = (X - LSL) 3σ Cp indicates the spread of variation present in a process. When a business process meets customer requirements, whether it's manufacturing or service-based, it’s known as process capability. If process spreads as Car B the garage capability will be low, however, if a process is narrowed like C or D we could see that the process is capable to perform as per customer's expectations. So we sample 32x and we can calculate the cpk of the dimension from the 32x data. Process Capability Index – Cpk: This is the capability index which accounts for centering of process and is defined as the minimum of Cpk upper and Cpk lower. Process capability – Cp: This is defined as the tolerance width divided by the total spread of process. Therefore, the engineers conclude that the forging process meets the requirements for the diameters of the piston rings. 1. The process of maintaining this temperature has a standard deviation of 2 degrees Celsius. Measuring the process capability index allows you to see if you have the right combination of materials, equipment, people and methods, by comparing the output of a stable process with the process specifications. The capability indices Cpk, Ppk, and Cpm are all greater than 1.33, which is a generally accepted minimum value for a capable process. First, don’t get these guys judging Cp without looking at Cpk also. Process Capability analysis Process: - T ake representative sample of process output - Statistical analysis of samples (Ma thematical tools, Scattered Plot, Pareto Chart, Let’s take an example. This was well written in entertaining story style. 0.83 6(0.03) 2.05 1.90 6 = − = − = σ USL LSL Cp Process is not a capable process since Cp<1.0 The above example shows the capability of the garage, the example itself explains what is the process capability. The Cp and Cpk indices are used to evaluate existing, established processes in statistical control. Process capability index formula with process capability example. Process Capability (Cp) is a statistical measurement of a process's ability to produce parts within specified limits on a consistent basis. However, I have a real problem with two statements. Process Capability (Cp) and Performance (Cpk) Chart Capability (Cp) and performance (Cpk) charts illustrate a process’s ability to meet specifications. Process Capability Index Example A manufacturing process produces a certain part with a mean diameter of 2 inches and a standard deviation of 0.03 inches. We want to know the capability of the process . For example , if a dimension is a key characteristic of a product , we have USL and LSL from the drawing. I’ve used similar examples when teaching process capability. Cpk is the smallest of the Cpu and Cpl. Cpk is used to estimate how close you are to a given targe The index Cp provides a measure of potential process capability i.e. [Actual] Process Performance Analysis (Pp, Ppk) Although SPC control charts can reveal whether a process is stable, they do not indicate whether the process is capable of producing acceptable output—and whether it is performing to capability. The lower and upper engineering specification limits are 1.90 inches and 2.05 inches. 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