### Home > INT3 > Chapter 7 > Lesson 7.2.2 > Problem 7-72

A glass factory makes a continuous ribbon of glass by pouring a continuous stream of hot, liquid silicon on a lake of molten tin. The liquid silicon spreads out evenly on the tin and then cools into glass. It is a process that must continue uninterrupted

Hour | ||||||||||||

Defects |

Hour | ||||||||||||

Defects |

Create an

‑bar process control chart with a UCL ofand an LCL of . Make a graph where the

-axis is Hours, the-axis is Defects.

The-axis should range fromto . What do you notice about the process control chart that might concern you as a quality control engineer?

Answers will vary, but notice that there appears to be a cycle every

hours.