To find the capability index (Cp), determine the difference between the upper specification limit (USL) and lower specification limit (LSL). Then, divide this difference by six times the standard deviation (σ).
Capability Index Calculator
Enter any 3 values to calculate the missing variable
The capability index calculator is an effective tool for measuring how well a process fits within set specification limits. It’s used widely in manufacturing. It ensures that quality standards are consistently met.
The Cp index checks if a process is capable of producing output within acceptable limits, while Cpk measures if the process is centered within these limits. This calculator is crucial for maintaining quality and improving operational efficiency.
Formula:
| Variable | Description |
|---|---|
| USL | Upper Specification Limit |
| LSL | Lower Specification Limit |
| σ | Standard Deviation of the process |
Solved Calculation:
Example 1:
| Step | Calculation |
|---|---|
| Determine USL and LSL | USL = 150, LSL = 100 |
| Calculate difference (USL – LSL) | 150 – 100 = 50 |
| Multiply 6 with σ | 6 × 5 = 30 |
| Divide difference by 6 × σ | 50 / 30 |
| Result | 1.67 |
Answer: The capability index (Cp) is 1.67.
Example 2:
| Step | Calculation |
|---|---|
| Determine USL and LSL | USL = 120, LSL = 90 |
| Calculate difference (USL – LSL) | 120 – 90 = 30 |
| Multiply 6 with σ | 6 × 4 = 24 |
| Divide difference by 6 × σ | 30 / 24 |
| Result | 1.25 |
Answer: The capability index (Cp) is 1.25.
What is a Capability Index Calculator?
The capability index calculator is a crucial tool that is used to measure the performance of a process in meeting specified limits. It uses statistical measures to determine the capability indices, such as Cp and Cpk, which indicate how well a process is performing. Realistically, this information helps in quality control and process improvement.
To calculate the capability index (Cpk), you need the process mean, standard deviation, and the specification limits. Cp measures the potential capability, while Cpk shows how centered the process is within the limits.
A Cpk of 1.33 or higher is typically considered a good standard for process capability, indicating that the process is well within specification limits with minimal defects.
Final Words:
To sum things up, to measure the capability index is crucial for assessing and improving a process’s efficiency and consistency. Moreover, using a reliable calculator simplifies this process and helps ensure quality control.
