Chapter 24, Problem 1CS

The KC Machine Works, which does job shop machining, has received an order to make 40 duplicate pieces, made of AISI 4140 steel, which will require 1 hr/piece of actual cutting time if a high-speedsfeel (M1) milling cutter is used. Abigail Langley, a new machinist, says the cutting time could be reduced significantly if the company would purchase a suitable tungsten carbide milling cutter. Paul Zachary, the foreman for the milling area, says he does not believe that Abigail’s estimate is realistic, and he is not going to spend $450 (the current price from the vendor) of the company’s money on a carbide cutter that probably would not be used again. The machine hour rate, including labor for the shop is S40/h.

Abigail and Paul have come to you, the manufacturing engineer (MfE) of the plant, for a decision on whether to buy the cutter, which is readily available from a local supplier.

What factors should you consider in this situation? How much faster could the carbide cutter cut compared to the HSS cutter? See Table CS-24. Based on your best guess as to the savings in actual cutting time per piece, who do you think is correct: Abigail or Paul?