Question

A copy machine is available 18 hours a day. On a typical day, the machine needs to process 320 jobs. Each job takes about 1.5 minutes on the machine, 0.5 minute of which is processing time and 1 minute is setup time (logging in, defining the job). About 25% of the jobs need to be reworked, in which the set?up time and the processing time have to be repeated once. In the remaining time, the equipment is idle. You would need to show steps and use 2 decimals in calculations.

(a)[2] Draw a tree diagram to show the breakdown of equipment time. Alternatively, you can opt to draw a diagram like Figure 8.1 (page 214) to illustrate the breakdown of equipment time.

(b)[2] Define and calculate total non?value added time in minutes.

(c)[2] Define and calculate total value?added time in minutes.

(d)[3] Calculate total waste time in minutes. Give a detailed breakdown of waste time.

(e)[1] What is the OEE of the equipment? (percentage, 2 decimals, i.e. 23.67%)

Answer 1

(b) Total available time = 18x60 =1080 min.

Total processing time = 320x0.5 = 160 min

Total set up time = 320x1 =320 min.

Total rework time = 320x0.25 ( 1+0.5) =120 min.

Total Non value added time = set up time + rework time = 320+120 = 440 min.

(c) Total value added time = processing time = 160 min.

(d) Total waste time = set up time + rework time + Idle time = 320+120+ 480 = 920 mn.

(e) OEE = processing time / time available = 160/1080 = 0.1481 = 14.81%

(a)