GATE VALVE – PROCESS CONTROL DETERMINATION

PURPOSE:

Students will be given a project to put to practice what they learned regarding process control, designing and creating a process control chart to determine if a process is in control, and what steps are necessary to fix a process if it is proven to be out of control.

PROCEDURE:

You work for ABC Company, which makes gate valves. It is your job to guarantee that the valves, when working, are designed and made to flow water at 3 gallons per minute when fully open. Any restriction or misplaced gaskets in the opening will alter this flow rate. You must make inspections on the manufacturing line and conduct tests in order to be able to make the guarantee. The inspections are made at the end of the line and require that you test a sample of the valves over an eight day period. For each valve sample, you will take a valve at the beginning of each hour; test the valve by measuring the flow for one minute; and record your results in a table. At the conclusion of your samples, you will then create the appropriate process control chart in order to be able to determine if the operation is in control. You will then need to make a report of your findings.

To save you time, samples were taken a few days ago, and this is the chart that was used to record the data collection.

Flow Rate in Gate Valve Inspection (gal/min)
Day / 9 AM / 10 AM / 11 AM / Noon / 1 PM / 2 PM / 3 PM
1 / 3.11 / 3.20 / 2.99 / 2.85 / 3.00 / 3.08 / 2.90
2 / 2.98 / 3.01 / 2.86 / 2.55 / 3.06 / 3.18 / 3.11
3 / 2.86 / 2.99 / 3.01 / 3.10 / 3.03 / 2.99 / 3.10
4 / 3.05 / 3.04 / 2.95 / 3.08 / 3.01 / 2.96 / 2.89
5 / 2.58 / 3.25 / 3.16 / 3.08 / 3.01 / 2.99 / 2.98
6 / 3.09 / 3.03 / 3.06 / 3.02 / 2.99 / 2.95 / 3.01
7 / 3.12 / 3.04 / 2.65 / 2.99 / 3.30 / 3.03 / 2.99
8 / 3.01 / 2.97 / 2.98 / 3.01 / 3.00 / 3.01 / 3.02
  1. Using your notes from the information provided you regarding process control and how to make process control charts, determine what type of Process Control Chart you need to develop for this set of data.
  2. After designing and developing the appropriate process control chart, plot the results for the appropriate chart.
  3. Prepare a report that explains your findings along with a recommendation of what may cause the process to be out of control or under control.

CONCLUSION QUESTIONS:

  1. Did you develop the appropriate statistical process control chart? How do you know?
  2. Was the process under control or out of control? How do you know for certain?
  3. What conclusions can you say about the data obtained and how the line is running?

Ohio – SREB – Course 1 – Introduction Project – Gate Valve – Process Control Determination

Copyright 2012Page 1