Question

A plastic injection molding (PIM) machine for Lego figures makes two different parts (yellow

bodies and red hats). One of each part goes into a final assembly, and the takt time for the

assembly station is the same as the production cycle time = 30 sec/assembly. The cycle time for

the PIM machine is 180 seconds to make 18 parts. The setup time to switch between molds on

the PIM machine is 12 minutes. To manage inventory, a Kanban system is established between

the PIM machine and assembly. The bin size is chosen to be 36 based on the size of the part,

the available space in the assembly area, and the consumption rate. The PIM department will

continue to make a part as long as there is an empty bin available for whatever color it is

running. If there is not an empty bin available, it will wait for the next empty bin to determine if

it should change. Both PIM and assembly work the same hours. Transport time from assembly

to PIM is a maximum of 18 minutes, and is also a maximum of 18 minutes from PIM to the

Kanban area for assembly. Assume that OEE = 1.

What is the part usage (demand) for both yellow and red parts in parts/hour?

Answer 1

Please find the below Solution:

Below is a diagram depicting the current Manufacturing & Assembly Scenario.

Takt time is the rate at which we need to complete a product in order to meet customer demand.

i.e., Takt Time = Production Time / Customer Demand

Takt Time = 30 Secs/ Assembly

Production Time we would take 60 mins i.e., 60x60 = 3600 Secs. for calculation of per hour requirement.

Now As per the formula:

30= 3600/Demand

Demand = 120 units/hr of assembly.

Hence individually we require

Yellow Bodies requirement - 120 units/hr

Red Hats requirement - 120 Units/hr

Total units required/hr = 240 Units