Page 311 - ExtendSim User Guide
P. 311

Activity-Based Costing 285
Modeling with activity-based costing
In the Receive Inven-
tory model described
earlier, cost rates for
the laborer are defined
in the Resource Item’s
Cost tab. The block’s
dialog indicates that
items stored in the
block are resources, as Cost tab of Resource Item block, providing resources seen at right.
☞ For the Resource Item block to provide resources, the Cost tab must be set to Items are: resources, the default choice. Otherwise the items will be cost accumulators, as discussed ear- lier.
You can also define cost information in activity-type blocks; those costs are accumulated by each item the block processes. The activity-type blocks are the Activity, Convey Item, Trans- port, and Workstation. Within the Cost tab of these blocks, enter a cost per time unit and a cost per item:
• Theprocessingcostpertimeunitisusedtocalculatethetime-basedprocessingcostofeach item that passes through the block.
• The cost per item is a fixed cost added to every item that passes through the block.
☞ The Activity block has a PC (Processing Cost) input for targeting different processing costs on different items as well as a CPI (Cost per Item) input to attach a unique CPI to each item.
Combining resources with cost accumulators
As discussed in “Modeling resources” on page 223, there are two ways that items can use resources. One method is to batch a resource item with another item. While batched, the resource item is in use and cannot be used by another item until it is unbatched and returned to the Resource Item block. The second method is to use the resource pool blocks, which act as a constraint on the flow of items throughout the model. This section discusses how to properly use these two methods when performing ABC.
Batching and unbatching resources with cost accumulators
The Resource Item block holds resources for use in the model. When batching a resource item with a cost accumulator, the resource’s cost rates are automatically stored with the cost accu- mulator and used in any subsequent cost calculations.
☞ A maximum of two separate types of resource items can be combined with a cost accumulator at a time. For instance, one or more worker resources from a Resource Item block and one or more cart resources from a different Resource Item block.
To unbatch a resource and remove its cost rate information from the cost accumulator, you must select Release cost resources as the Unbatch block’s behavior. This choice tells the block to modify the information stored with the cost accumulator to indicate that the resource has been released.
☞ If the Unbatch block’s behavior is set to Create multiple items, the items released by the block will be identical to the item which entered the block. In other words, there would be mul- tiple copies of the cost accumulator, and each copy would still be joined with the resource.
Discrete Event

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