Question

question: mixed model sequencing
an assembly line produces three models (x, y and z) of small engines used in lawn mowers and portable electric generators. next month, they need to produce 200 model x, 100 model y and 100 model z. which of the following assembly sequences is preferred if the company wants the schedule to be as level as possible?
a. xyzxxyzxxyzxxyzx (repeated 25 times during the month)
b. zxzyzxzyzxzyzxzy (repeated 25 times during the month)
c. yxzxyxzxyxzxyxzx (repeated 25 times during the month)
d. xxxxyyyyxxxxzzzz (repeated 25 times during the month)

Explanation:

Step1: Calculate total units

Total units = $200 + 100 + 100 = 400$

Step2: Find unit per repeat cycle

Units per cycle = $\frac{400}{25} = 16$

Step3: Find required ratio per cycle

X per cycle = $\frac{200}{25} = 8$; Y per cycle = $\frac{100}{25} = 4$; Z per cycle = $\frac{100}{25} = 4$

Step4: Count units in each option

Option A: Count X,Y,Z in sequence

Sequence: XYZXXYZXXYZXXYZ (16 units). X count=8, Y count=4, Z count=4

Option B: Count X,Y,Z in sequence

Sequence: ZXZYZXZYZXZYZXZY (16 units). X count=4, Y count=4, Z count=8

Option C: Count X,Y,Z in sequence

Sequence: YXZYXZYXZYXZYXZX (16 units). X count=9, Y count=4, Z count=3

Option D: Count X,Y,Z in sequence

Sequence: XXXXYYYYXXXXZZZZ (16 units). X count=8, Y count=4, Z count=4 (but clustered, not level)

Step5: Select most level sequence

Option A has correct counts and balanced distribution, while D has clustered units.

Answer:

A. XYZXXYZXXYZXXYZ (repeated 25 times during the month)