Process capability and machine capability are two of the capabilities which work in completely different areas. Process capability refers to the overall process capability, specifically in terms of all chucks, fixtures, etc. The machine’s capability takes into account the capability of only one chunk, fixtures, etc.
Process capability is determined by utilizing specialized software, whereas machine capability is determined by a third-party evaluator or its manufacturer. The difference between process and machine capability does not end here. There are many other differences which are discussed below.
Key Takeaways
- Process Capability measures a process’s ability to meet specific requirements, while Machine Capability evaluates a machine’s performance over a short period.
- Process Capability considers factors such as long-term variation and machine wear, whereas Machine Capability focuses on short-term performance.
- Machine Capability is used as a baseline to compare different machines, while Process Capability measures overall production efficiency.
Process Capability vs Machine Capability
Process capability refers to the ability of a process to consistently produce products that meet the desired specifications. Machine capability refers to the ability of a machine to produce parts or components that meet the desired specifications. It is a measure of the machine’s ability to perform within certain tolerances.
Process capability is referred to as a statistical measure of a given characteristic’s inherent process variability. It can be used to assess the process’s ability to meet specifications. During an initiative of quality improvement, a capability estimate is obtained in the study from start to end to reflect improvement.
Machine capability is referred to as a measure of a machine’s actual quality concerning its specifications. This is a short-term capability derived from the observations of the uninterrupted production run. When measuring machine capability, altering machine tools and changing settings is not preferred.
Comparison Table
| Parameters of Comparison | Process Capability | Machine Capability |
|---|---|---|
| Interpretation | It is a statistical measure of a given characteristic’s inherent process variability. | It is the measure of the machine’s actual quality with respect to its specifications. |
| Time | Long | Short |
| Focuses | On production processes | On machines themselves |
| Biased | Not biased | Biased |
| Formula | Cp = (USL-LSL)/6σ | Cm = USL – LSL / 6s |
What is Process Capability?
The processing capability is the process’s measurable property to the specification. It can be expressed as a process performance index and process capability index. The output is illustrated with the help of a histogram and calculation of this measurement. They mainly predict how many parts can be produced out of specification (OOS).
Process capability has mainly two parts to measure the variability of the process output and compare that variability with a product tolerance and proposed specification. The process input has at least one or more measurable characteristics to specify outputs. The number of components included in process capability is 50- 250.
A process should be estimated with suitable process controls in place. To determine if the process is “statistical control”, the control chart analysis is used. The capability has no meaning in case the process is not in statistical control. Consequently, the process capability consists of only common cause variation but not special cause variation.
The process output is expected to meet the customer’s requirements, engineering tolerances, or specifications. Engineers conduct the study of process capability to determine the extent of the process to meet these expectations. It mainly centres on the whole product delivery process from conception to delivery routes.
What is Machine Capability?
Machine capability is the measure of actual quality with respect to the specifications of the machine. It mainly refers to the capacity parameters of a specific piece of machinery. The parameters consist of the number of raw materials or loads, the time between services, and the machine’s production speed.
The production speed is the most important capacity of a machine. With the help of the extension, the machine tries in the least possible time to operate in doing all tasks. It centres on the machine’s capacity to deliver on the production process. The production line could be affected due to any lag in speed.
Machines and measurements highly influence the result of machine capability. Manufacturers of machines list all of the particular capabilities of a machine in the user manual. But it is also important to check with a test for a third-party machine capability to acquire a better-quality machine for a certain job.
The third-party inspection also has another benefit like revealing the real machine capabilities. As well as to detect mechanisms that can help to prevent future problems. Machine alternate parts and accessories can also enhance by machine capability.
Main Differences Between Process Capability and Machine Capability
- Process capability centres on the whole product delivery process from conception to delivery routes, whereas machine capability centres on the machine’s capacity to deliver on the production process.
- Process capability is calculated on sample individual and subgroup both with average x bar, while calculation of machine capability is done on target value with the unchanged condition in individual sample standard deviation.
- Process capability is determined by utilizing specialized software, whereas machine capability is determined by a third-party evaluator or its manufacturer.
- Process capability is part of the development of the product. On the other hand, machine capability is an evaluator for the purposes of buying.
- Process capability is heavily dependent on data, especially graphical data. On the other hand, machine capability is reliant on performance.
- https://www.tandfonline.com/doi/abs/10.1080/00224065.1986.11978984
- https://www.sciencedirect.com/science/article/pii/S0924013604001074
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