# A company is conducting a feasibility study into a flexible production system for tennis shoes. The shoes the line must produce are constructed in an 11-step fashion as described in Table 2. The line of shoe is an international best seller with a required output per day of 4000 shoes. Based on two 8-hour shifts (so 16 hours of total available production time), (a) determine the takt time, (b) determine the theoretical minimum number of workstations, (c) assign tasks to the individual workstations using the ‘largest eligible task’ rule, and (d) determine the efficiency delay of the proposed line. TASK TIME (SEC) PREDECESSOR(S) A 12 None B 14 A C 7 A D 5 B,C E 3 D F 2 None G 1 F H 8 E,G I 13 H J 4 I K 10 J Marci spends 15 hours researching and writing a 20-page report for her philosophy class. Jack brags that he has a “streamlined” process for performing the researching and writing. Jack takes just 8 hours to research and write the paper, but his report is only 15 pages long. Calculate Marci and Jack’s productivity. What is the output? What is the input? What are the limitations of using productivity measures to evaluate Marci’s and Jack’s performance? What other performance measures might the instructor use? Smarmy Sales, Inc. (SSI) sells herbal remedies through its website and through phone reps. Over the past six years, SSI has started to depend more and more on its website to generate sales. The figures below show total sales, phone rep costs, and website costs for the past six years: YEAR TOTAL SALES PHONE REP COSTS WEB SITE COSTS 2012 \$4,790,000 \$200,000 \$50,000 2013 \$5,750,000 \$210,000 \$65,000 2014 \$6,900,000 \$221,000 \$85,000 2015 \$8,280,000 \$230,000 \$110,000 2016 \$9,930,000 \$245,000 \$145,000 2017 \$11,920,000 \$255,000 \$190,000 Calculate productivity for the phone reps for each of the past six years. Interpret the results. Calculate the productivity for the website for each of the past six years. Interpret the results. Calculate a multifactor productivity score for each year, where the “input” is the total amount spend on both the phone reps and the website. Interpret the results. Why might this be a better measure than the ones calculated in parts a and b?

(1)

(a)

4000 shoes are to be produced in 16 hours. So,

Takt time = 16 x 60 x 60 / 4000 = 14.4 sec

(b)

Theoritical total number of wrokstations = Total flowtime / takt time

Total flowtime = 12+14+7+5+3+2+1+8+13+4+10 = 79 sec

So, theoritical minimum number of workstations = 79 / 14.4 = 5.49 (or, 6)

(c)

Station tasks Time (seconds) Time left (seconds) Ready tasks Station Station
A,F cycle time idle time
1 A 12 2.4 F,B,C 14 0.4
F 2 0.4 B,C,G
2 B 14 0.4 C,G 14 0.4
3 C 7 7.4 G,D 13 1.4
D 5 2.4 G,E
G 1 1.4 E
4 E 3 11.4 H 11 3.4
H 8 3.4 I
5 I 13 1.4 J 13 1.4
6 J 4 10.4 K 14 0.4
K 10 0.4
Totals 79 7.4
(d)

Efficiency delay = Total idle time / (No. of stations x overall cycle time) = 7.4 / (6 x 14.4) = 8.56%