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In building this model we must define all of the basic modeling elements and a few of the optional elements.
We need some type of receiving location to hold incoming entities. We also need processing locations where entities have value added to them. For the given production rate, Cogswell's engineers have determined that the workcell will require two NC_300 series numerically controlled mills, a degreasing machine, and an inspection/assembly station.
The entity types in this system include Pallets, each carrying six cast Blanks. Blanks become Cogs after processing, and Bearings are loaded at the Inspect station. If a Cog fails the inspection it will be called a Reject.
Cogswell's engineers have determined that Pallets should arrive at the rate of 1 Pallet every 45 minutes.
The operation at each mill requires an operator to load the Blank, which takes a normally distributed amount of time with a mean of 3 minutes and standard deviation of .2 minutes (i.e., N(3,.2)). After a blank has been loaded, the machining time is a constant 5.7 minutes.
Cogs are then removed from the mill and placed in the degreasing machine. The degreasing machine has capacity for 2 Cogs, and has a cycle time of 5 minutes.
Once the Cogs have been degreased, they are inspected for proper spline depth, and a bearing is installed in the center hole. This process requires the cell operator, and takes U(3.2,.3) minutes for the inspection and U(1.5,.2) minutes for the Bearing to be installed. If the Cog fails inspection, no Bearing is installed.
A single operator, CellOp, performs all manual operations.
In order to make CellOp a mobile resource, we must define a path network. We'll call it CellNet.
An attribute is simply a "numeric tag" attached to either an entity (entity attribute) or a location (location attribute). Since each Cog is inspected for proper spline depth, we attach an attribute called Test to each Cog, specifying the Pass/Fail status of the Cog.
We will sample from a user defined distribution and set the Test attribute to either 1 (for pass) or 0 (for fail). Ninety six percent of the Cogs pass inspection and have their Test attribute set to one. Four percent fail the inspection and have their Test attribute set to zero.