When it comes to on-site label printing, there really is no such thing as an "ideal" manufacturing environment. In many cases, your products, and therefore your labels, may have to endure exposure to some unpleasant conditions.

Harsh chemicals, common cleaning solvents, abrasive elements, temperature fluctuations and inclement weather top the list of possible threats to labels. Because industry labeling demands are not forgiving, you must take preventive measures to ensure bar code readability and the endurance of your labels overall.

Everything counts when label printing in harsh environments — from label material and ribbons to labeling equipment. Following are some considerations to keep in mind when discussing your application with your label supplier.

It's in the label
Potential labeling problems can be eliminated right from the start by choosing the proper pressure-sensitive label material for your application. The key is knowing exactly what your bar code labels have to endure before arriving at their destination. Will drastic temperature changes affect the facesheet or adhesive? Will labels be exposed to chemicals or cleaning solvents? Will bar codes have to withstand UV rays or other outdoor elements?

By tracking the path of your labels and being aware of all aspects involved with your application, you can have the appropriate label material custom manufactured with the correct facesheet and adhesive combination.
The facesheet, or printing surface, can provide its own source of protection. Several different levels of resistance exist in facesheet materials, either naturally or synthetically.

Standard paper-based materials are at the first level. Coated or uncoated, they are cost-efficient and durable for many general applications. By adding top coatings or film overlaminates, paper labels can be equally effective in harsh labeling environments.

For example, if you have bar coded labels that will be exposed to moisture, a stronger latex-saturated paper label can provide the resistance you need. For even stronger outdoor protection, a special UV varnish on top of that will retard the effects of continued exposure to sun, wind and rain.

The next level of protection comes from film-based label materials, such as polyethylenes and polypropylenes. Films are inherently stronger than paper labels and can be manufactured even stronger, not to mention more attractively, by treating them with varnishes. The marketplace offers a variety of these films in both matte and gloss finishes.

One type of film option for some industries is tagstock materials, which do not require adhesive. Most tagstocks are made of a sturdy vinyl or polyethylene film and are frequently used to curtail the outdoor labeling hazards of the horticultural and forest products industries.

Probably the most durable film facesheet available is a polyester. Its abrasion-resistant features increase the longevity of bar codes and other printed information, which is ideal for meeting stringent UL and CSA requirements in nameplate and rating plate applications.

When working with pressure-sensitive labels, also remember that not all adhesives are alike. The right adhesive depends on the surface being labeled as well as the labeling environment. For many stressful labeling applications, an acrylic-based adhesive is recommended over a rubber-based one. Acrylics adhere very well to a variety of substrates and can endure a wide range of temperatures. Plus, they possess long aging characteristics and resist UV degradation.

On-site bar code printing that lasts
Having the right equipment to print your bar codes and variable information is equally important as having the proper labels to print them on. With the correct label printer, ribbons and label material, today's on-site printing systems offer high-quality results for harsh environments.

Thermal-transfer printers produce excellent results in less than ideal conditions. They are compatible with films, varnishes and other facesheet coatings, and, when using the correct wax or resin ribbon, they leave a clear image that won't fade or smudge.

Designed for industrial use, on-site thermal-transfer printers are versatile enough to accommodate media ranging in size from small printed circuit board labels to large chemical drum labels. They deliver up to 300 dpi resolution for high-density bar codes and text with a throughput rate up to 8.0" per second. Models also can be integrated into print/apply systems for automatic label printing and application.

Before sending a printed label into a harsh enviroment, one last crucial step is bar code verification. The best way to guarantee bar code readibility is to make sure you're printing the best possible bar codes from the start. On-line verifiers, which attach right to the front of thermal-transfer printers, read bar codes as they are being printed. If a bad bar code is sensed, the printer will stop automatically. This final precautionary measure reassures you that your system is producing the highest quality labels for your application.

Everything counts every time
Because the petrochemical industry is one of the harshest on bar code and product identification labels, it acts as good example of how every element counts in an on-site labeling system.

Petrochemical manufacturers that label hazardous material identification labels on-site often utilize a polypropylene film material with an acrylic adhesive. Sometimes a varnish is added to the labels for extra protection of any preprinted colors or text.

Then an on-site system, which includes a thermal-transfer printer, an on-line verifier and a compatible ribbon, is used to print bar codes and variable information. Users can then confidently apply their labels, knowing they took all the precautionary measures to ensure label longevity.

Even if you think you're bar coding in the "ideal" environment, your labels may have potential hazards to contend with. Basic soap and water or minor abrasions during shipping can smudge or smear your bar codes and other data. Talk to your label supplier about your application. There are a variety of alternatives for the special bar code labeling needs in the chemical, outdoor, electrical, electronic and food environments. By taking preventive measures in the beginning, you can save yourself a lot of money and frustration later.