Which chart would you use for following cases: a). A process characteristic that

Question

Which chart would you use for following cases:

a). A process characteristic that is measured with a micrometer, and the product rate is very slow (only one part is produced every one to two weeks.

b). A 100% inspection process at the end of the manufacturing line, where the percent defective is recorded for each lot, and the number of units changes from one lot to the next.

c). The number of late work orders per day for a given company that is a supplier.

d). A length dimension that is captured using a computer vision system for sample sizes ranging from 5-7. The measurements are obtained and computed automatically on a computer at the process.

Explanation / Answer

a) Control charts (RANGE CHART):

The control chart is a graph used to study how a process changes over time. Data are plotted in time order. A control chart always has a central line for the average, an upper line for the upper control limit and a lower line for the lower control limit. These lines are determined from historical data. By comparing current data to these lines, you can draw conclusions about whether the process variation is consistent (in control) or is unpredictable (out of control, affected by special causes of variation).

b) c-BAR CHART

The c-bar chart plots the number of defects or failures per unit. It is based on the Poisson distribution. The number of bags mishandled on a flight by Air Canada might be monitored by a c-bar chart.

c) Gantt charts

The most common method of scheduling is by use of the Gantt chart. This is a simple device which represents time as a bar, or channel, on a chart. The start and finish times for activities can be indicated on the chart and sometimes the actual progress of the job is also indicated. The advantages of Gantt charts are that they provide a simple visual representation both of what should be happening and of what actually is happening in the operation

If it is a simple number of late work orders, a line graph would be more than sufficient

d) xbar and r chart

An Xbar-R chart plots the process mean (Xbar chart) and process range (R chart) over time for variables data in subgroups. This combination control chart is widely used to examine the stability of processes in many industries.

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.