Dj Automotive Process Improvement Plan

Process Improvement Plan

In 2011, DJ Automotive was selected to introduce a new version of an automotive keyless entry fob. The fob consists of four parts (control chip, rolling transmitter, plastic housing, and key ring) and the company receives the parts from suppliers located throughout the world (Canada, Japan, United States, and Taiwan). In its original contract, the company was responsible for supplying fobs to 835,000 cars per year (2 fobs per car). Because of their outstanding quality and delivery rates, DJ Automotive has added another dealership and increased their production for the next six months by 50,000 fobs each month (Figure 1).

With this increased production, DJ Automotive will need to ensure the company is producing at the most efficient methods and will need to make sure they have a very detailed process improvement plan.

Figure 1

Control Limits

Chase, Jacobs, and Aquilano (2006) state Statistical Process Control (SPC) is an application of statistical methods for testing a random sample of an output from a process to determine if a process is producing items within a specified range (p. 364). It is used so that companies can detect any shifts in a process and to make the changes needed. If a process is 'in control', it means that the mean and upper and lower control limits (as calculated by using the standard deviation) are operating such that the controls are acceptable in relationship to the requirements. The upper and lower control limits (also called natural process limits) are calculated by using the mean of a process and adding/subtracting three standard deviations from the mean. In our process improvement plan, we will utilize SPC throughout the processes to ensure we meet our customer's requirements. A process can be in statistical control but may not be producing product according to the design (product or process) because it is based on the sample data. It is key to ensure that the requirements are acceptable in relationship to the control limits.

In the production of the fobs, the key ring assembly has the longest cycle time. In the prior production runs, the average cycle time has been 4.89 seconds with an upper (5.32) and lower (4.45) control limit calculated from the standard deviation. With the increased forecast, it will be mandatory that the key assembly be completed every 6.1 seconds. Because the requirement of the process is well outside the key ring process's control limits, we believe that we will be successful in meeting the production forecast. As part of the improvement plan, we will implement the monitoring of the key ring assembly cycle time. Production will take readings (three times a day) to ensure that we are operating within the control limits (Figure 2).

Figure 2

Confidence Intervals

According to the Statistics Glossary (n.d.) a confidence interval gives an estimated range of values that is likely to include the true value. Confidence intervals allow organizations to make estimates about the population of a process or product. The intervals are based on a sample of the process or product rather than the entire population. The width or range of the confidence interval gives us some idea about how certain or uncertain we are about the data. A