Dillons Bakery has received a rush order for five specialty

Dillons Bakery has received a rush order for five specialty cakes: a wedding cake, a birthday cake, a graduation cake, a retirement cake and an anniversary cake. Baking these cakes involve two processes: baking and decorating (in that order). The time required for each job differs depending on the size and type of the cake. Given the following processing times (in hours) determine the order in which the cakes should be processed so that the rush order will be completed as soon as possible. Find that completion time (i.e. find that makespan) Cake Baking Decorating 4 Birthday Wedding Anniversary Retirement Graduation 8 6

Solution

We will use Johnson’s rule to solve this problem

Johnson’s Rule is:

Here , the jobs are various “cakes”

Work centers are “Baking” and “decorating”

Based on above, order in which cakes should be bakery

Graduation - Anniversary – Retirement – Wedding -   Birthday

Calculation of completion time ( time in parenthesis is cumulative hours to complete ) :

Baking : Graduation ( 3) Anniversary ( 8) Retirement ( 14) Wedding ( 22) Birthday ( 31)

Decorating :                  Graduation ( 12 ) Anniversary( 19) Retirement ( 25) Wedding ( 30) Birthday ( 35)

Thus completion time is 35 hours

COMPLETION TIME = 35 HOURS

COMPLETION TIME = 35 HOURS