Slotting Exercises

Here are a set of activities to demonstrate some of the capabilities of the software. The first section walks you through a basic slotting. The second section shows how you can use the software to help evaluate alternative designs of the forward area.

Before you begin, you will need to download the following sample data files:

Basic slotting

Load data, slot rack
Tab 1: Load a file of SKUs that are candidates for forward storage
From the program menu bar select SKUs : Import from text file... and then use the file chooser to select “skus.tab”. (There should be a companion file “skus.schema” in the same directory; this tells the program how the data is structured. If the program cannot find such a file, it asks for the structure of the data file.) Note that the program filters out any SKUs with inconsistent data so that they can be examined later.
Tab 2: Load a file describing the forward storage mode
From the program menu bar select Rack : Load rack description... and then use the file chooser to select “flow rack.properties”. The program displays the details of rack geometry and lets the user set policies on how it is to be slotted, including desired clearances, slot dimensions, stacking, case orientations, etc.
Tab 2 (continued): Optimally slot SKUs into rack
Click on the button labeled “minimize labor” at the bottom of the screen. The program will optimally configure the rack and fill it with the optimal subset of SKUs to minimize total labor (costs of picking from the forward area plus costs of picking from reserve or bulk storage plus costs of restocking the forward area).
Examine results
Tab 3: Click on the tab named “Statistics” to evaluate the results.
  • Click on the “SKUs” tab to see a pie chart of where SKUs are stored. Note that 26 percent of the SKUs were chosen for forward storage
  • Click on the “Activity” tab to see a pie chart of how many picks are projected to be from the forward area, how many from reserve, and how many restocks will be necessary to maintain the forward area. Note that 79 percent of the picks are projected to be from the forward area. (Hold the pointer of the pie chart to see the exact number.)
  • Click on the “Labor” tab to see that a total of 4,800 person-hours are required to meet the forecast movement of product.
  • Click on the “Activity by bay” tab to see how many picks are expected from each bay of rack. The software has concentrated picking as instructed. By hovering over the blue chart we can read that the ten busiest bays are responsible for 68 percent of the picks — later we may want to go back and re-slot the ten busiest bays to equalize the activity among them and so avoid congestion.
Tab 4: Click on the tab named “Face charts” to see the slotted rack.
This display confirms that the proposed slotting plan is realizable. And it lets the user quickly search for problems with the data. For example, it is evident that, in Bay #21, the leftmost SKU on the 2nd shelf from the bottom has been stacked on its edge, which does not seem stable. This suggests that the longest dimension was erroneously entered as height in the SKU data.
Tab 5: Click on the tab named “Results” to see a table describing where each SKU is stored.
You can save this table for further processing, perhaps by a spreadsheet or database program.
Tab 6: Click on the tab named “Exceptions” to see a list of SKUs that were not chosen for forward storage, with an explanation for each decision.
The decisions of the optimization engine are fully auditable.)
Save your work

You can print face charts or save the results for further processing. You can save the entire scenario by selecting File : Save work… from the program menu bar.

Compare alternatives

This section shows how to use the program to answer higher level questions. It assumes you have completed all the steps of the previous section.

How much rack is needed?

Use the program to compute the value of the last five bays of rack. Return to the “Rack” tab and change the number of bays of flow rack from 30 to 25. (Be sure to tab out of the field after changing the value, so that it will be registered.) Press the button “minimize labor” and then click on the “Statistics” tab and the “Labor” display, where you will read that 4,928 person-hours are now required. This reveals that those five extra bays of rack, from 25 to 30, are worth 4,968 minus 4800, or 168 person-hours.

To account for product churn, space in the rack should be easy to manage.

Tell the program to allocate space in more regular chunks, say in quarters of a shelf. Return to the “Rack” tab and change the number of bays back to 30. Change the “#-slots/shelf” to 4. Change the “#-slots/sku” to 4 to allow each sku to fill one-quarter, one-half, three-quarters, or a full shelf. Press the button to “minimize labor”. Check the “Statistics” tab and see that 5,210 person hours are now required, so it will cost 5,086 minus 4,800 = 286 person-hours to regularize space allocations. (See what they look like under the “Face charts” tab.)

Forward space is scarce so squeeze SKUs in.

Tell the program to allocate space in smaller amounts: Return to the “Rack” tab and set “#-slots/shelf” to 128 and the maximum “#-slots/sku” to 128. Also set the “max #-skus/shelf” to 25. This will allocate space in tiny increments and squeeze more SKUs onto the shelf. Press the “minimize labor” tab and examine the results under the “Statistics” tab, where the “Labor” graph shows that 4,624 person-hours are required. This means that using a very tight packing can save at most 4,800 minus 4,624 = 176 person-hours. You can examine that tight packing under the “Face charts” tab.