Exam I - Review Questions- KEY2

Several identical machines are available if each

This preview shows page 2 - 3 out of 3 pages.

……………………………………………………………………………………………………… Several identical machines are available. If each machine is used for 7.0 hours per shift, two shifts per day, and 20 days per month, how many machines will be needed to meet the aggregate requirement? (Assume negligible setup time). Total time needed = 3280 * 1 = 3280 hours / month No. of machines = 3280 / ( 2 * 7 * 20) = 11.71 Round up We need 12 machines. Product Time Hrs / unit Demand Demand in standard units A 2.0 80 (2/1 *80 ) 2 * 80 / 1 = 160 B 3.0 200 (3/1 *200 ) 3 * 200 / 1 = 600 C 1.5 480 (1.5/1 *480 ) 1.5 * 480 / 1 = 720 D 4.0 320 (4/1 *320 ) 4 * 320 / 1 = 1280 E 1.0 520 (1/1 *520 ) 1 * 520 / 1 = 520 Aggregate Requirement 3280
Image of page 2

Subscribe to view the full document.

Review Question 1 Consider the three-stage process shown here with hourly capacity of each machine. What is the cycle time at Stage 1 20 +12 = 32 units / hr. 1/32 *60 = 1.88 min/unit What is the cycle time at Stage 2 8+10+12 = 30 units / hr. 60 * 1/30 = 2 min / unit. What is the cycle time at Stage 3 10+15 = 25 units / hr. 1/25 *60 = 2.4 min/unit Which stage is the bottleneck? Stage 3 has the longest cycle time (and lowest capacity) Stage Capacity (units/hr) Bottleneck 1 20 + 12 = 32 Stage 3, lowest capacity 2 8 + 10 + 12 = 30 3 10 + 15 = 25 ……………………………………………………………………………………………………… What is the minimum TPT? = 12 minutes Machine G1 P3 M2 Total Time (min) 3 5 4 12 (1/20 * 60) (1/12 *60) (1/15 *60) Suppose two new machines are added to the process (in parallel to other machines at a stage): P4 at stage 2 (with cycle time = 10 min / unit) and M3 at stage 3 (with cycle time = 6 min / unit). What is the process productivity? (There is one worker per machine). Capacity of P4 = 60 * 1/10 = 6 units / hr, capacity of M3: 10 units / hr. New capacities will be: Stage 1: 32, Stage 2: 30 + 6, Stage 3: 25 + 10. Bottleneck is at stage 1. Total number of workers = 2 + 4 + 3 =9. Productivity = 32/9 = 3.56 units per hr per worker. P1 8 P2 10 P3 12 M1 10 M2 15 G1, 20 G2, 1 2 Stage 1 Stage 2 Stage 3
Image of page 3
You've reached the end of this preview.
  • Spring '10
  • panwalker
  • Cycle Time, Hour

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern