Rates and Buffers

Now, we can set up the rates for the constraints and capacities for the remaining buffers.

Rates

From the video, we know 2 rates:

• Each molding machine is capable of producing 5,000 cookies per hour

• The packaging line is capable of processing 3,000 assembled cookies per minute

To keep this example simple, we will set all constraints in the baking lines and packaging line to those rates converted to correct units, respectively.

For the baking lines, we will need to first convert the hourly rate into a rate per minute. 5,000/60 = 83.333 cookies per minute. We will round this up to 84 cookies per minute for simplicity. All constraints from "Molding" to "Cream Pump" on both baking lines will receive this rate.

Baking Line Rate

In order for the mixers to process enough ingredient mix for 84 cookies per minute, they must consume 84 x 0.008811 = 0.74 pounds of ingredient mix per minute. We will round this up to 0.75 pounds per minute.

Mixer Rate

The assembly constraints need a rate of 0.5 x 84 = 42 full cookies per minute to keep up since each assembled cookie consumes two cookies.

Assembly Rate

Finally, all of the packaging steps will receive a rate of 3,000/36 = 83.333 packages per minute, which we will also round up to 84.

Packaging Rate

Buffers

Next, we will handle the buffers. We have already taken care of the initial buffer in a previous step, so the first buffer we are concerned with is for baked cookies. Recall that these lines are producing cookies at a rate of approximately 5,000 per hour. We will set up a 4 hour buffer of 20,000 cookies on both lines.

The next buffer we have to worry about is for the assembled cookies after the baking lines merge. Combined, both baking lines are producing assembled cookies at a rate of approximately 5,000 per hour. Again, we will set up a 4 hour buffer of 20,000 assembled cookies.

The final buffer is for finished product. We want to make sure this one has infinite capacity to capture the full production during the simulation.

It is easiest to edit all of the buffers at once from the "Buffers" tab on the nav bar:

Buffers