311 A A certain batch of parts is routed through six machine

3.11 (A) A certain batch of parts is routed through six machines in a batch production plant. The setup and operation times for each machine are given in the table below. Batch size is 100 and the average nonoperation time per machine is 12 hours. Determine (a) manufacturing lead time and (b) hourly production rate for operation 3 Machine Setup time (hours) ation time (min 5.0 3.5 6.2 2.5 3.13 A batch production plant processes an average of 35 batches of parts per week. Five of those part styles have been selected as a sample for analysis to assess the production performance of the plant. The five parts are considered to be representative of the population of parts processed by the plant. Any machine in the plant can be set up for any type of batch processed in the plant. Batch quantities, numbers of operations in the processing sequence, setup times, and cycle times for the parts are listed in the table below The average nonoperation time per batch per operation is 11.5 hours. The plant operates 40 hours per week. Use this sample to determine the following measures of plant performance: (a) manufacturing lead time for an average part, (b) plant capacity if all machines could be operated at 100% utilization, and (c) work-in-process (number of arts-in-process). Use of a spreadsheet calculator is recommended for this problem Part 100 240 85 250 140 5.0 3.8 4.0 9.3 8.4 12.0 5.7 3.2 11.5 11.5 11.5 11.5 11.5 3.5

Solution

3.11(A)

For operation 3, the set up time is 8hrs and manufacturing time for a batch of 100 is 6.2 X 100 = 620 mins

a . Thus the total manufacturing lead time including the set-up time will be 620/60 = 10.3hrs + 8 hrs = 18.3 hrs for a batch of 100 pcs

b. Hourly production rate for operation 3 = 60/6.2 = 9 pieces in an hour.

3.13 a. Manufacturinf lead time of all parts is as follows

Part A is 15.3 mins

Part B is 9.35 mins

Part C is 14.82 mins

Part D is 7.164 mins

Part E is 4.7 mins

average time = 10.26 mins

b. Full capacity

Part A produced in 40 hrs = 193 pcs

Part B produced in 40 hrs = 240 pcs

PArt C produced in 40 hrs = 160 pcs

Part D produces in 40 hrs = 356 pcs

Part E produced in 40 hrs = 487 pcs

Therefor total parts produced in full efficiency = 1436 pcs

c. Work in progress = 6+3+4+8+7 = 28 pcs