Natalie examined the X and R charts developed from the data presented in Table HS.1. The R chart indicated that the process is in control, but the X chart revealed that the mean for batch 17 was outside the lower control limit. This imme- diately gave her cause for concern because low values for the roller diameter could mean that parts had to be scrapped. Natalie went down to see Jim Murante, the shop foreman, to try to find out what had happened on batch 17. Jim looked up the production records to determine when this batch was produced. "Aha," He exclaims, "I think I've got the answer! This batch was produced on that really cold morning we had last month. I've been after Mr. Harnswell for a long time to let us install an automatic thermostat here in the shop so that the place doesn't feel so cold when we get here in the morning. All he ever tells me is that people aren't as tough as they used to be." Natalie stood there almost in shock. What she realized had happened is that, rather than standing idle until the envi- ronment and the equipment warmed to acceptable tempera- tures, the machinist opted to manufacture parts that might have to be scrapped. In fact, Natalie recalled that a major problem had occurred on that same day when several other expensive parts had to be scrapped. Natalie said to Jim, "We just have to do something. We can't let this go on now that we know what problems it is potentially causing." Natalie and Jim decided to take enough money out of petty cash to get the thermostat without having to fill out a requisition requiring Mr. Harnswell's signature. They installed the thermostat and set the heating control so that the heat would turn on a half hour hefore the chon onened each morning hour before the shop opened each morning. EXERCISES HS.4 What should Natalie now do concerning the cam roller data? Explain. HS.5 Explain how the actions of Natalie and Jim to avoid this particular problem in the future has resulted in quality improvement. DO NOT CONTINUE UNTIL YOU HAVE COMPLETED THE PHASE 3 EXERCISES TABLE HS.1 Diameter of Cam Rollers (in inches) Cam Roller Batch 3. 5076 5075 5075 5075 5076 5077 5075 5076 5074 3075 5075 5076 S075 5074 5076 5076 5076 5077 5076 5075 5076 5073 5075 5075 5075 5076 5073 2. 4. 5075 5076 5076 3075 5076 5076 5076 5077 5075 5076 S076 5076 5076 5075 5074 5075 5075 5075 5076 5075 5074 5075 5076 10 5076 5075 5075 5075 5076 5077 5076 5076 %3D 5075 5075 5075 5075 5073 3074 5076 5075 5075 3074 5075 12 13 3076 3075 5075 14 15 5075 5074 5073 16 5075 5074 5076 5075 5075 17 5075 5075 5076 5074 5075 5074 5072 18 5075 5076 5075 5076 19 20 21 22 23 5076 5075 5075 5076 5075 5074 5074 5076 5076 5077 5075 5075 5075 5075 5076 5075 5076 5075 5076 5074 5075 3076 5076 5075 3075 3074 3076 5075 24 5076 25 5075 5075 5075 5075 5077 5075 5077 5075 5074 5075 5075 5076 5075 26 5076 5075 5076 5075 5076 5074 5076 5075 5075 5076 27 5074 5075 5074 5075 28 29 30 5076 5075 5075