6 Ways to Boost Scanning Accuracy

Nov. 1, 2010
These simple measures can improve bar-code reading performance and save money—and you don’t have to call for outside help.

If your bar-code scanning is 99.5 percent accurate, it’s costing more than you realize. Even a small percentage of no-read or mis-sorted packages mounts up quickly. For example, in a DC that ships 50,000 packages per day, if only half a percent (0.5 percent) are no-reads, and if each instance requires only three minutes of manual labor to correct, then that cost adds up to $62,500 per year. Realistically, how many DCs get close to 0.5 percent on a consistent basis? It’s not uncommon to see error rates in excess of 3 to 5 percent.

While perfection may be unattainable, improvement can pay for itself quickly, resulting in increased throughput and greater customer satisfaction. This article looks at some common issues and provides suggestions on how to squeeze the most performance out of your bar-code system.

1. Do Simple Maintenance

Today, most scanning systems require very little attention to keep them running. New designs have all but eliminated the moving parts and filters that used to require routine maintenance. However, it is still important to establish and follow a simple maintenance schedule to ensure peak performance.

Just cleaning the exit windows on laser bar-code scanners or the lens and illumination of camera bar-code scanners, along with any associated mirrors, can make a surprising difference in the system’s read rate. One large retail DC achieved a half-percent increase in its read rate after a technician cleaned the windows of its scanner system. That’s why managers should make bar-code systems maintenance an integral part of their overall preventive maintenance program.

2. Note Packaging Changes

A major clothing retailer noticed an increase in error rates when it changed its packaging. New plastic bags designed for the holidays were highly reflective. Similarly, managers at a home improvement DC noticed a sudden decline in read rates as inventory changed to summer merchandise, which included more oversized items such as rakes and ladders. Changes in package type can adversely affect bar-code scanning system accuracy. Managers should adjust the scanning system to accommodate the changes in package flow. Typically, this means changing some of the scanner’s parameters via the set-up software.

3. Watch for Size, Speed, Spacing Changes

A wine-and-spirits distributor increased throughput requirements in an existing facility and saw a drop in read rates. Bar-code systems are set up for specific transport speeds and spacing between packages. In this case, the systems integrator was able to adjust the scanning system’s timing to accommodate the demand for increased throughput.

4. Look for Multiple Labels

Multiple labels on boxes can cause issues with bar-code scanning systems, especially if they are in sortation operations. Often, manufacturers put bar codes on boxes for their own purposes and these can confuse distribution center equipment. In other situations, an equipment error in print-and-apply systems results in two labels being applied mistakenly as packages are received in the DC. A verification scan immediately downstream of the label print-and-apply equipment will detect multiple labels. For these cases, scanning systems are set up with a pre-programmed list of bar-code symbologies. All decoded labels are compared to this list and the system will flag conditions whenever multiple codes are detected on one package for special handling. Keeping this list current is important.

5. Improve Label Quality

Bar codes that are torn, smudged, dirty, poorly printed, or on dark backgrounds are a fact of life for DCs, and these situations challenge all bar-code scanning systems. Take measures to ensure bar-code quality and reduce the potential for damage.

Camera-based scanners work by capturing an image of a label and decoding it. Most cameras offer image capture tools for performing root cause analysis on no-reads that result from poorly printed and damaged bar codes. By viewing these images, an operations manager may be able to diagnose the reasons for no-reads and address the issue quickly. For example, the shipping-label printer may be running low on ink or there may be multiple bar codes on packages. Troubleshooting no-reads in this way will decrease the expense of manual processing while increasing throughput by a percentage point or more.

6. Detect Side-By-Sides

Sometimes, multiple packages end up on the same tray on a tilt-tray sorter or next to each other on a belt conveyor. This can result in mis-sorts and mis-shipments, costly manual detection and handling, and even conveyor jams (causing downtime) or damage to packages. Most DCs don’t know exactly how much money these events are costing them, but they are probably more costly than they expect.

Side-by-side-package detection software can minimize mis-shipments and eliminate the need for manual detection and handling. Two major retailers installed a side-by-side package detection system on one scan tunnel each. Combined, the bar-code systems detected a total of 58 side-by-side packages in a single shift, saving $2320 by avoiding manual handing and shipping costs. Projected over a year, the savings are expected to reach $846,800 for the two retailers combined.


Regardless of the effort expended to get the most from an existing system, in some cases, dropping read rates may indicate it’s time to upgrade the bar-code scanners. This is especially true if it is an older model that has provided years of service. A major airport in the Midwest recently upgraded its old laser bar-code scanners, which were becoming costly to service. They immediately experienced increased read rates, jumping from 70 percent to an average of 99 percent.

In today’s uncertain economy, DC managers are quickly realizing that wringing out even small gains in efficiency and performance can pay big dividends. Fortunately, the causes of bar-code scanning system no-reads and mis-sorts can often be diagnosed quickly and improvements can be made that way too.

Loren S. Meck is product manager for Accu-Sort Systems, Inc.