Batch Order Picking for 300 Line/hour (LPH) Productivity

My first encounter with a real life batch picking operation was a medium size drug wholesaler in the mid-Atlantic region. This rather innovative company had an urgent need to increase picking productivity and had developed their own version of multi-order picking. They printed out a pick list for 15 totes that would be placed five each, on three shelves of a wheeled pick cart. The pick document listed the items to be picked on the left side of the paper followed by 15 columns, one for the pick quantity into each of the 15 pick totes.

In spite of the obvious difficulty of using a 15 column pick list, they found that pick productivity was more than doubled (to about 160 lines per hour) due to the greatly reduced walking time. Unfortunately, the accuracy was so poor, they had to hire one checker for each picker. In spite of the problems however,, productivity was increased enough that they continued to use this new technique.

Several years later we visited a mail order vitamin and supplement distributor who was using a 5 column pick list to pick 5 orders in one pick trip. Since the product and orders were quite small (most would fit in an 8 inch square carton) all 5 orders would easily fit on a small 2 shelved cart which could be wheeled in the narrow pick aisles. Since the pick path for their 12,000 SKU’s was about 1000 feet, past shelving, pallet rack and some flow rack, even 5 orders at a time saved significant travel time and they achieved a pick rate of about 150 lines per hour.

There was always the possibility of picking the wrong item or putting items into the wrong box, so they developed an in-house barcode scanning system to 100% verify each order. This scanning was done by the picker, reducing the total pick/check productivity to about 110 lines per hour, still a very good rate for a system with 12,000 products and all picking operations performed manually.

Based on the good results observed on the two operations above, as well as the knowledge that LL Bean had successfully used batch picking in their early catalog distribution operation, we proposed a custom radio frequency (RF) terminal picking operation for a new home delivery grocery operation. Since the home delivery of groceries would be expensive, it was imperative that picking and replenishment be as productive as possible.

By directly packing dry groceries onto recycled grocery store shelving along with the use of a limited amount of 10’ deep flow rack for higher movers, a minimal cost system capable of holding 1 to 5 days of all items was developed. The grocery orders were cubed at midnight each day and trucks routed for efficient delivery the next afternoon and evening. By cubing each order, we assigned it one to three compartments in a wheeled pick cart.

A plastic grocery bag with a bar coded address label was placed into each of the 16 compartments on the wheeled cart and logged into the RF terminal as "A" to "P". The terminal directed the picker to each pick location in order. A pick was made by scanning the product’s UPC bar code to verify the correct item was picked. The cart compartment was scanned to verify the item went into the correct order. Counts for more than one piece were scanned to verify quantity. When all picks in the cart (6 to 15 orders) were completed the grocery bags were placed into covered totes for delivery. Any product shortages were updated to the RF system so that accurate delivery invoices could be printed after picking was completed.

Approximately 2000 dry grocery and drug items, ranging from paper towels and soda bottles to aspirin and baby food, were in the pick line which stretched about 1400 feet. The pick rates for the three best pickers averaged 270 lines per hour. This was achieved without conveyor or any need for QC accuracy checking! When product was received, it was scanned with the RF terminal and the slot number designated by the system was written on the cartons. They were sorted by aisle, scanned for inventory control, and packed out directly to flow rack or shelves. The highest moving items were put in rack or floor pallet slots so that no reserve inventory system was required. As an extra benefit, the terminal system made it easy for temporary help to pick accurately in a very short time.