Intro to Control Charts

- Defect trend data is collected and problems are corrected

All employees in the plant benefit when __________. - Data on a specific employee's performance is collected and analyzed - Engineers keep their distance from hourly personnel - Operators can choose what hours they work - Defect trend data is collected and problems are corrected

- The process capability

Control charts are used to determine __________. - The amount of rework required - The process capability - The machine cycle time - Worker's vacation time

- Historical data

Control charts provide __________ to allow manufacturers to analyze problems on a piece of equipment. - Quality specifications - Safety information - Historical data - Maintenance data

- Fix problems before bad parts are produced

Control charts show trends and patterns in data over time. What does a control chart allow operators to do? - Prepare data - Fix problems before bad parts are produced - Visually see parts being produced - Count the number of good parts

- Capable manufacturing processes

Processes that run in control are considered __________. - Capable manufacturing processes - Inferior manufacturing processes - Standard manufacturing processes - Substandard manufacturing processes

- Attribute

Statistical process control has two types of data. Which one is mostly used with go/no go gauges? - Variable - Multiple - One step - Attribute

- Low customer complaint data

What data would indicate that a production process is in control? - Low customer complaint data - High operator job performance data - Both A and B - None of the above

- The average value of each subgroup

What does the X-bar chart plot? - The number of operators present - The range of each subgroup - The average value of each subgroup - The median value of each subgroup

- Circle out-of-control patterns

What is a good practice in analyzing an X-bar and R chart? - Circle stable patterns - Underline out of control patterns - Circle out-of-control patterns - Circle repeating patterns

- The boundaries within which all data values should lie

What is indicated by control limit lines on X-bar charts and R charts? - The time scale - A subgroup's average measurement for each time interval - The average value for all product made by the process - The boundaries within which all data values should lie

- Part variation will increase

What often happens if operators make adjustments to recently produced parts based on recent measurements? - Part variation will decrease - Part variation will increase - More parts will be processed - There will be no change

- Attribute sampling

When making a yes-or-no decision, what type of sampling should be used? - Attribute sampling - Variable sampling - Defect sampling - All of the above

- Power surge

When only one point is outside the X-bar or R chart control limits, what special cause may have occurred? - Inexperienced operator - Power surge - Tool wear - Lubrication cycles

- X-bar and R chart

Which control chart tracks two aspects of data? - Process chart - P-chart - SPC Chart - X-bar and R chart

- Plot data over time with a control chart

Which of the following is the best way to predict the future performance of a process? - Interview the operators - Review maintenance logs - Plot data over time with a control chart - None of the above

- In an unstable process, the mean of the measurements is outside the control limits of the process. The process should be investigated

How is an unstable (out-of-control) process defined, and what should be the response? - In an unstable process, the mean of the measurements is outside the control limits of the process. The process should be investigated - In an unstable process, the mean of the measurements is within the established control limits with only natural causes of variation. No investigation is needed - In an unstable process, a process is producing parts faster than expected. No investigation is needed - In an unstable process, a process is producing parts faster than expected. It should be monitored closely to see if the next sample will fall outside the control limits

- Range

The X-bar chart relies on averaging measurements of parts. What is the other calculation plotted on the R chart? - Mean - Range - Median - Average

- Measurement units

The data for an X-bar and R chart places time intervals on the X-axis and what other data from the sample on the Y-axis? - Measurement units - File - Transfer - Speed

- Control chart

Variable and attribute data are used to define what type of chart? - Control chart - Process chart - Inspection chart - Audit chart