control charts for attributes
Download
Skip this Video
Download Presentation
Control Charts for Attributes

Loading in 2 Seconds...

play fullscreen
1 / 6

Control Charts for Attributes - PowerPoint PPT Presentation


  • 124 Views
  • Uploaded on

Control Charts for Attributes. p chart (fraction of nonconforming items) np chart ( number of nonconforming items) c chart (number of nonconformities in some unit) u chart (number of nonconformities per unit). The p Chart Procedure.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Control Charts for Attributes' - bunme


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
control charts for attributes
Control Charts for Attributes
  • p chart (fraction of nonconforming items)
  • np chart ( number of nonconforming items)
  • c chart (number of nonconformities in some unit)
  • u chart (number of nonconformities per unit)
the p chart procedure
The p Chart Procedure

Step1. Gather the data. Select the size, frequency and number of samples.

Step2. Calculate p for each sample.

Step 3. Set the scale for the control chart.

Step 4. Plot the p values and connect them.

Step 5. Calculate p-bar, and the control limits after about 20 points have been charted.

Step 6. Interpret the chart

chart interpretation
Chart Interpretation
  • Shifts. A shift of seven or more points to a higher or lower level could mean that something has affected the proportion defective or that the definition of what is defective has somehow changed.
  • Trends. A run of seven or more points up or down indicates that something is causing the proportion that is defective to change in a gradual manner, poorly trained operators, different inspection criteria, or poorly controlled parts in the assembling process.
the np chart
The np Chart
  • Standard given:

UCL = np0 +3np0 (1-p0)

LCL = np0 - 3np0 (1-p0)

  • No standard given:

UCL = x + 3  x (1- x/n)

LCL = x - 3  x (1- x/n)

the c chart
The c Chart
  • Standard given

UCL = c0 + 3 c0

LCL = c0 - 3 c0

  • No standard given

UCL = c+ 3c

LCL = c- 3c

the u chart variable unit size
The u Chart(variable unit size)

u = c/k k is the number of inspection

units in each sample

UCL = u0 + 3 u0/k

LCL = u0 - 3 u0/k

ad