MANUFACTURING PROCESSES
HOMEWORK 3
Due Date: December 16, 2012
1. Three tool materials are to be compared for the same finish turning operation on a batch of 100 steel parts: high speed steel, cemented carbide, and ceramic. For the high speed steel tool, the Taylor equation parameters are: n = 0.125 and C = 70 (m/min). The price of the HSS tool is $15.00 and it is estimated that it can be ground and reground 15 times at a cost of $1.50 per grind. Tool change time is 3 min. Both carbide and ceramic tools are in insert form and can be held in the same mechanical tool holder. The Taylor equation parameters for the cemented carbide are: n = 0.25 and C = 500 (m/min); and for the ceramic: n = 0.6 and C = 3,000 (m/min). The cost per insert for the carbide is $6.00 and for the ceramic is $8.00. There are 6 cutting edges per insert in both cases. Tool change time is 1.0 min for both tools. The time to change a part is 2 min. The feed is 0.25 mm/rev, and depth of cut is 3 mm. The cost of machine time is $30/hr. The part is 56.0 mm in diameter and 290 mm in length. Setup time for the batch is 2.0 hr. For the three tooling cases, compare: (a) cutting speeds for minimum cost, (b) tool lives, (c) cycle time, (d) cost per production unit?
2. Rotech Inc. is a mid-scale manufacturing company and a supplier of spare parts to major automobile companies. In general, mid-scale companies carry high levels of inventory in order to able to respond quickly to the orders coming from companies. Production planning is important in order to find the right level of inventory. Rotech recently purchased an enterprise resource planning (ERP) software in order to improve production planning. Aslı Akbaş is the head of process planning department. She is responsible for the implementation of the ERP software, and she needs to know the processing times and unit cost information of all the machining processes. Aslı wants to do everything right so she puts her