Question

Dittenhoefer’s Fine China

introduction

Overall, Steve Edwards, vice president of Marketing at Ditten-hoefer’s Fine China, is very pleased with the success of his new line of Gem-Surface china plates. Gem-Surface plates are differ-ent from regular china in that the plates have a special polymer coating that makes them highly resistant to chipping and fad-ing. Not only are the plates more durable, they are also com-pletely dishwasher safe.

In order to manufacture the new plates, Dittenhoefer’s has leased a special machine to apply the coating and has put in place a drying system to “cure” the coating on the plates. The research and development (R&D) lab has determined that in or-der to prevent defective plates, it is important that the machine apply the polymer coating at the proper temperature and in the proper thickness. Specifically, R&D has written up the following guidelines:

Coating Thickness. The optimal polymer- coating thick-ness is 4 microns. If the coating is 7 5 microns, the plates will take too long to dry. If the coating is 6 3 microns, the plates will be inadequately protected.

Coating Temperature. The polymer coating needs to be applied at a temperature between 160 degrees Fahrenheit and 170 degrees Fahrenheit, with the target temperature being 165 degrees Fahrenheit. If the temperature is lower than 160 degrees, the polymer will not adhere properly and will flake off. If the temperature is higher than 170 degrees, the polymer coating will fade the design on the plates.

Quality Problems

Traditionally, quality control at Dittenhoefer’s has consisted of visually inspecting finished items for defects (chips, cracks, etc.) as they are being packed for shipment. This was accept-able in the past, when defects were few and far between. With the new polymer-coating technology, however, this has caused some serious problems.

For instance, on one Friday during the Christmas sea-son, the packers noticed that nearly all of the plates they were getting ready to ship had faded designs, which suggested that the temperature of the polymer-coating machine might be too high. Sure enough, when a supervisor went back to check on the polymer-coating machine, he found that the thermo-stat was set at 190 degrees. Apparently, someone had set the temperature higher to clean the machine but had forgotten to reset it back to 165 degrees. The good news was that the problem was easily fixed. The bad news was that the ma-chine had been running at 190 degrees since Wednesday. In the interim, 2,400 plates had been run through the coating machine. In the end, Dittenhoefer’s had to destroy all 2,400 plates and was late making shipments to several important customers.

In another instance, a worker just happened to notice that the polymer-coating machine was not using as much raw mate-rial as expected. When the worker measured the thickness of the coating being applied to the plates, she found out why: The coating thickness was only 2.4 microns. A quick check of plates being dried and those being packed revealed that they, too, had a coating thickness of around 2.4 microns. While manufactur-ing was able to correct the problem and save these plates, no one knew how many plates had been shipped before the prob-lem was discovered.

the customer service department

The customer service office is responsible for pricing and en-tering customer orders, tracking the progress of orders, and making sure orders are shipped when promised. If an order is going to be late or there is some other problem, the customer service office is also responsible for notifying the customer. In addition, the customer service office handles customer complaints.

As would be expected, Steve Edwards often visits the larger dealers to find out how satisfied they are with the prod-ucts and service they have received. During one of these trips, Steve realizes there might be problems with the customer ser-vice office. When visiting Nancy Sanders, owner of Lenoir Home Furnishings, Steve gets an earful:

Steve, I understand that you have been busier ever since you introduced the new line of plates. However, I feel that the service quality has deteriorated and no one seems to care! Just last week, I found that an order I had expected in on Monday was not even ready to ship. No one called me—I just happened to find out when I was calling to place an-other order. Your information system also seems to be an-tiquated. The sales assistant apologized for the shipment delay and tried to be helpful, but she couldn’t tell me the status of my order or even when I had placed it! It seemed that the previous sales assistant had changed jobs, and no one knew where her notes were. Notes!? Why isn’t this stuff on a computer? It makes me have serious reservations about doing business with you.

Steve is caught flat- footed by the criticism. When he gets back to the office, he puts together a letter to his top 200 customers. In the letter, he gives customers a self-addressed stamped postcard and asks them to list any problems they have had dealing with the sales office. He gets responses from 93 of the customers­. Their responses are summarized here:

	Number of
	Respondents Citing
Problem	Problems
Incorrect pricing	23
Lost the order	8
Did not notify customer	54
with regard to change in
delivery date
Did not know status of	77
customer’s order
Order incorrect—wrong	4
products shipped
Slow response to inquiries	80
Other problems, not	11
listed above

References

Suppose the polymer-coating machine currently provides the following results:

		Process Standard
Variable	Process Mean	Deviation
Temperature	165 degrees	2.55 degrees
Thickness	4 microns	0.42 micron

Polymer-Coating Machine: Sample Temperature and Thickness Measurements (taken when the process was under control)

	Temp/	Temp/	Temp/	Temp/	Temp/
Sample	Thick	Thick	Thick	Thick	Thick
June 10	165/4.2	169/3.9	165/4.0	164/4.0	169/3.9
June 15	161/3.8	165/4.2	166/4.0	167/4.8	165/4.2
June 20	169/3.9	161/3.8	167/4.8	164/4.0	167/4.8
June 25	164/4.1	168/4.0	166/4.0	165/4.0	163/3.5
June 30	166/4.0	168/4.0	169/3.9	163/4.3	166/3.7
July 5	168/4.0	163/3.5	167/4.8	164/4.0	166/4.0
July 10	162/4.5	164/4.1	169/3.9	167/4.8	163/3.9
July 15	163/3.5	168/4.0	165/4.0	165/4.0	167/4.8
July 20	167/4.8	167/3.2	164/4.1	167/4.8	164/4.1
July 25	167/3.2	163/3.5	168/4.0	165/3.8	168/4.0
July 30	163/4.0	165/3.8	165/4.2	169/3.9	163/4.0
August 5	163/3.8	165/4.2	169/3.8	165/4.2	163/3.5

Q:1. On which dimensions of quality does Dittenhoefer’s compete? How are these dimensions being threatened by the problems in the manufacturing and customer service areas?

2. What do you think are the problems with the current manufacturing process as a whole and with the polymer-coating machine in particular? How might you use process mapping and root cause analysis to get to the bottom of these problems?

3. Develop a Pareto chart based on the customer survey results for the customer service office. What seems to be the key problems? How might you use the PDCA cycle to go about resolving these problems?

4.Suppose the polymer-coating machine currently provides the following results:

		Process Standard
Variable	Process Mean	Deviation
Temperature	165 degrees	2.55 degrees
Thickness	4 microns	0.42 micron

Calculate the process capability ratio (C_p) for both the tem-perature and thickness variables. Is the polymer-coating process able to meet the engineering standards 99.7% of the time? Explain.

Answer 1

1.

The Quality dimensions Dittenhoefer compete on include performance, feature, reliability, durability, and perceived quality. The manufacturing problems have some issues with monitoring the machine, visually inspecting finished items for defects (chips, cracks, etc.) as they are being packed for shipment, and using the required raw materials. Those problems that have led to some defects may have a negative impact on the quality dimensions that Deisenhofer is trying to achieve. Also the customer service area has some issues.

2.

Leasing the special machine to apply the coating while the research and development team has mentioned some specifications for the machine to accurately apply the curing. The polymer-coating machine has to be adjusted in a way that plates do not take too long to dry and do not inadequate protected. Also, the temperature has to be adjusted between 160 and 170. Those can sometime be an issue because workers may have some human mistakes in working with the machine. The root cause analysis may lead to an automated process of adjusting the temperature and thickness level of the machine, so this way there is a minimum human involvement in it. A process mapping of clearly identifying the workflow would eliminate the issues, specially those of the customer service department. A basic workflow diagram on visio that shows how the order process is received from the customers and up t following up with them after delivering is a key element.

3.

Below is a pareto chart illustrating the different types of issues with the customer service department

The PDCA cycle stands for Plan Do Check and Act cycle of activity. Customer service team has to plan for the process of receiving and delivering an order then do implement it and check by testing it and finally starting acting by using it to make sure the above issues in the pareto chart are eliminated.

4.

After making numerous process improvements, Steve Edwards decides to set up control charts to monitor the temperature and thickness results for the polymer-coating machine. Sample temperature and thickness data are shown in the table below. Set up the appropriate control charts.

The process capability ratio for the temperature equal to the highest temperature minus the lowest divided by six times standard deviation.

= (170-160)/(6*2.55) = 65.36%

For thickness

Using same equation, the maximum thickens and the minimum divided by six times standard deviation for thickness.

= (5-3)/(6*0.42) = 79.36%

The Control charts are as following: Using the data from the case, the temperature control chart is illustrated below.

Similarly using the data for the thickness, the control chart is illustrated below:

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