The lower and upper engineering specification limits are 1.90 inches and 2.05 inches. Process capability – Cp: This is defined as the tolerance width divided by the total spread of process. 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. 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. First, don’t get these guys judging Cp without looking at Cpk also. Process capability index formula with process capability example. Therefore, the engineers conclude that the forging process meets the requirements for the diameters of the piston rings. 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. In simple words, it measures producer’s capability to produce a product within customer’s tolerance range. [Actual] Process Performance Analysis (Pp, Ppk) This was well written in entertaining story style. The above example shows the capability of the garage, the example itself explains what is the process capability. Example 2: - The training room temperature during the training must be kept between 18 degrees Celsius and 26 degrees Celsius. 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 When a business process meets customer requirements, whether it's manufacturing or service-based, it’s known as process capability. The Cp and Cpk indices are used to evaluate existing, established processes in statistical control. Let’s take an example. So we sample 32x and we can calculate the cpk of the dimension from the 32x data. 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. Take the example of a motorcycle driving in the same lane going in … Process capability index (Cpk) is a statistical tool, to measure the ability of a process to produce output within customer’s specification limits. However, I have a real problem with two statements. 1. 0.83 6(0.03) 2.05 1.90 6 = − = − = σ USL LSL Cp Process is not a capable process since Cp<1.0 Process Capability (Cp) and Performance (Cpk) Chart Capability (Cp) and performance (Cpk) charts illustrate a process’s ability to meet specifications. Process Capability analysis Process: - T ake representative sample of process output - Statistical analysis of samples (Ma thematical tools, Scattered Plot, Pareto Chart, When we talking about the capability of a process , we usually use cpk to show how well the process is. Cp indicates the spread of variation present in a process. I’ve used similar examples when teaching process capability. Cpk uses "s-short-term" to predict the behavior of the process. The process of maintaining this temperature has a standard deviation of 2 degrees Celsius. 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. The index Cp provides a measure of potential process capability i.e. Cpk is used to estimate how close you are to a given targe Process Capability (Cp) is a statistical measurement of a process's ability to produce parts within specified limits on a consistent basis. 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