LINE BALANCING

1. For the exercise described below, do the following:

a) Draw the precedence diagram

b) Calculate the cycle time

c) Calculate the theoretical number of workstations

d) Perform balancing using the weight method

e) Calculate the% efficiency of the line

EXAMPLE 2.1 Consider the assembly of the spring-activated toy car shown in Figure 2.4. To take advantage of a large local labor pool of persons wishing part-time day employment and part-time second jobs in the evening, two 4 hour-shifts will be used, 4 days a week for assembly. Each shift receives two 10-minute breaks. Marketing estimates have been used to obtain a planned production rate of 1500 units per week. With holidays, vacations, and other events, the plant averages only 4 working days per week. The set of tasks, times, and precedence constraints are given in Table 2.2. No zoning constraints exist. Immediate Predecessors Task b abcde/g ! Table 2.2 Toy Car Assembly Tasks Assembly Time Activity (seconds) Insert front axle/wheels 20 Insert fan rod 6 Insert fan rod cover 5 Insert rear axle/wheels 21 Insert hood to wheel frame 8 Glue windows to top 35 Insert gear assembly 15 Insert gear spacers 10 Secure front wheel frame 15 Insert engine 5 Attach top 46 Add decals 16 cd 8 b e.b 1 k2 ke