Logistics News

By Cliff Holste

January 11, 2012

Upgrading DC Controls Software Yields 20 to 30 Percent More System Handling Capacity

Boost Conveyor System Throughput Without Increasing Speed or Expanding the System

Given the anemic economy and extreme competitive conditions, most retailer businesses are in a position where they cannot pass along operational cost increases to their customers. At the DC order fulfillment is considered a core competency and as such the quest to improve never ends. Cost control and productivity improvement is essential. Going forward into 2012, many of these DCs will be looking to raise the bar on throughput, productivity and customer service levels while continuing to leverage down costs.

Large retailers, especially those with expanding retail chain store operations, typically operate multiple DCs in the +500K sq. ft. range, with some of them over a million square feet. It is relatively common for these DCs to be highly mechanized with 1000s of feet of conveyor including automated carton picking and sorting systems. With all this equipment the challenge is determining how to accommodate rising volume without incurring the cost of a major system overhaul, expansion, and/or adding more staff.

Holste Says: Going forward into 2012, many of these DCs will be looking to raise the bar on throughput, productivity and customer service levels while continuing to leverage down costs. What Do You Say? Click Here to Send Us Your Comments Click Here to See Reader Feedback

Tweaking DC Conveyor System Software Yields Higher Throughput

Increasing the throughput of a large and sometimes complex conveyor system usually means increasing equipment speeds. With 1000s of feet of conveyor and 100s of individual power units, this can be a daunting, time consuming and expensive task.

The ideal solution is to update the system software and controls so that the conveyor equipment can physically handle more product without increasing speed. This approach is gaining in popularity thanks to advanced software and controls that permit higher product density (carton population) per lineal foot of conveyor thus increasing the cases per minute handling rate.

There are two main areas where this advanced software solution can be beneficial - the central merge, and the shipping sortation system.

The central merge is the place in a conveyor system where production lines, transporting product from various receiving, cross dock, picking, special processing areas, and sometimes product being re-circulated by the shipping sorter, are collected into one main takeaway conveyor line feeding the sortation system.

The number of production lines being served by the central merge can be as few as 3 or 4 or as many as a dozen or more. Each line automatically releases a slug of product, one line at a time. Typically there is a time interval (referred to as a “gap”) between slugs amounting to several feet. These gaps alone can equate to a 10 to 15 percent loss of throughput.

Material handling engineers have developed software logic that can eliminate most of the slug gap losses. The software contains precise timing and tracking logic, which “knows” the distance and travel time between lanes. This allows a downstream lane to continue releasing for some time after an upstream lane has started to release, so that gaps between slugs are reduced to just a few inches regardless of line release sequence.