Issue:
The falling revenues that the company is experiencing coincide with delays in manufacturing. These delays, in turn, are due in large part to poor planning in purchasing metals. Consider further that the manager of the department that handles purchasing of raw materials has an excellent background in general business, psychology and sociology, but knows little about the properties of metals. The company should therefore move the purchasing manager to the sales department and bring in the scientist from the research division to be manager of purchasing department.

Analysis
The argument that moving the research dept. scientist to purchase dept. will reduce the delays in manufacturing and therefore increase the revenues is flawed.
By providing the background of the purchasing manager, the author explains that the purchasing manager does not have all the credentials required to judge the right quality or properties of the metal whereby consuming more time in purchasing the inventory. This is a valid argument partly because a technical assistant should be able to handle this job more efficiently.
However, as per the author's advise that moving the scientist from research department to the purchase department may improve the situation may not prove to be a viable option. A manager with all the required background in business, psychology and sociology is still required to negotiate the pricing with dealers and make right decision on the inventory. A scientist may not be qualified to do so.
Thus the argument can be improved by adding scientist to the purchase team to judge the right quality metals but keeping the current manager in the team at the same time in order to negotiate purchases and make thoughtful decisions on inventory management.
In conclusion, the argument is partially flawed and can be improved by introducing the above stated point which will eliminate the manufacturing delays whereby increasing the revenues.