Question 35 (Textile Engineering & Fibre Science)
For meeting the criterion of number of defects in a product, the relationship between upper control limit (UCL) and upper specification limit (USL) should be
| (A) | UCL < USL |
| (B) | UCL > USL |
| (C) | UCL = 2USL |
| (D) | UCL = (USL)3 |
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Frequently Asked Questions | FAQs
What is UCL and LCL?
UCL, LCL, and USL are statistical terms used in process control and quality management to define upper and lower control limits and upper specification limits.
UCL stands for Upper Control Limit, which is the highest value allowed within the range of acceptable variation for a process. It is calculated based on statistical analysis of process data, such as mean and standard deviation, and is used to monitor the process and detect when it is going out of control.
LCL stands for Lower Control Limit, which is the lowest value allowed within the range of acceptable variation for a process. Like the UCL, it is also calculated based on statistical analysis and is used to detect when the process is going out of control.
USL stands for Upper Specification Limit, which is the highest value allowed for a product or service to meet customer requirements or industry standards. The USL is often based on customer needs or regulatory requirements, and is used to ensure that the product or service meets these requirements.
Together, the UCL and LCL define a control chart, which is a graphical representation of process data over time that helps to monitor the stability and performance of the process. If the process data falls outside the control limits, it is an indication that the process is not stable and needs to be investigated and improved. On the other hand, if the data falls within the control limits but outside the specification limits, it may be an indication that the process needs to be adjusted to improve product quality.