Warehouse product slotting is a key issue in the efficient operation of the warehouse. Where you locate the warehouse picking slots for the various product SKUs will affect warehouse travel time. Travel time (i.e. distance covered during a picking cycle) accounts for the majority of total warehouse man-hours.
The most common method of warehouse product slotting is by product activity. The first step is to analyze 12 months of sales from the company business system (i.e. Invoice File). This will allow you to create Categories for the picking items.
For example, JDH reviewed 12 months of data for a small parts company. The result of the warehouse product slotting analysis was as follows.
- Cat A – Ordered at least once a week – 148 SKUs (2.4%). Account for 13,568 Picks (30% of all pick activity).
- Cat B – Ordered at least once a month, but less than once a week – 757 SKUs (12.3%). Account for 17,313 Picks (38% of all pick activity)
- Cat C – Ordered more than once a year, but less than once a month – 2,904 SKUs (47.4%). Account for 12,526 Picks (27% of all pick activity)
- Cat D – Ordered just once a year – 2,316 SKUs (37.8 %).Account for 2,316 Picks (5% of all pick activity)
Products will be slotted by activity (i.e. fast moving items closest to the staging area). This will mean that for shelf stored items, the first section of shelving provides 90 shelf units for the fastest moving items. Based on the activity analysis, 72% of all required picking will take place in this first section. This will improve picking a minimum 2 – 3 times current rates versus totally random slotting.
The same benefits occur for the racked stored items. Fast moving items will be stored closest to the staging. This means that by slotting Cat A and Cat B items in racks R1 – R10, 11A, 11B, 9a & 1A, 82% of all picking requirements will be contained in these 13 racks.