- SPECIAL REPORTS
We’ve all been there: You spent hours researching a new identification, tracking or data collection system. Just when the allocated funds have been spent and the scanners and management software systems are installed, you think: “Just one small task left to finish this huge project—pick a label.”
Only label selection isn’t a small decision to make. Most engineers quickly realize that choosing a label that will work perfectly for a specific application isn’t easy, and no one wants to spend the time or the money to test multiple labels.
To make things more complicated, a label consists of five elements, and each element must be considered when choosing a label. Those elements are:
- Release liner, which is used as a carrier for the label and protects the adhesive from dust and debris.
- Pressure-sensitive adhesive, which affixes the label to the surface.
- Face stock or film, which is the backbone of the label and provides a surface for the adhesive and topcoat.
- Printable topcoat, the part of the label that provides the background for printing.
- Printing, the text, codes or images that appear on the label.
Unfortunately, a magic genie does not appear every time you need to select a label material. “You need a tamper-evident label for an asset-tracking project in a harsh environment? Well then, a durable polyester base with a permanent acrylic adhesive is for you!”
So where should you turn if you need help while label shopping? The following five steps will point you in the right direction.
Step 1: Know Your Application
First things first: How will the label be used? What is its purpose? Simply identifying the application for the label is a great place to start, because it provides context for the other four factors to consider.
Do you need the labels for asset tracking, component identification and tracking, or printed circuit board (PCB) identification? Selecting the general use for the label will shed light on the next step in the path. For instance, asset tracking will most certainly require a high-quality bar code, possibly with chemical or abrasion resistance.
Other questions to consider include:
- Do the labels need to be permanent, removable or repositionable?
- Will the labels be applied manually or automatically?
Answers to both questions will influence the adhesion rate of the label.
Step 2: Environmental Considerations
The next factor to think about is the environments in which the labels will be used. This is critical to label material selection. The label’s elements—adhesive, face stock and topcoat—must be able to withstand the environment for the label to perform successfully and continuously.
Will the labels be used indoors or outdoors? Will they be exposed to extreme heat or cold? Will they be applied in extreme or ambient temperatures? Will the labels be exposed to chemicals? Will they be exposed to abrasion?
Answers to these questions will help you pick the right material. For example, labels for equipment identification projects may face may be exposed to water and chemicals, while a label for PCB identification project will most certainly be exposed to very high temperatures.
Step 3: Surface Properties
Next, consider the surface to which the labels will adhere. Specifically, you’ll want to think about the surface material (glass, polycarbonate, powder-coated metal, stainless steel) and the surface characteristics (smooth, rough, flat, curved, low-surface energy, high-surface energy). A thicker layer of adhesive or ultra-aggressive bonding chemistry is good for incon-sistent surfaces.
There are four classes of adhesives to choose from:
- Rubber-based adhesives. Typical applications include nameplates on textured plastics and curved surfaces, as well as wire and cable markers.
- Acrylic-based adhesives. Typical applications include industrial tapes, asset identification, graphics labels and work-in-process applications, such as PCB identification.
- Silicone adhesives. Typical applications include high-temperature components, including PCB identification and low-surface-energy surfaces.
- Activated adhesives. These remain tack-free until either heat, solvent, pressure or other methods activate the adhesion.
Step 4: Regulatory Requirements
After you have identified the surface elements that will influence your adhesive choice, the next factor you need to think about is the regulatory requirements for the labels.
There’s an alphabet soup of regulatory agencies and requirements out there, including UL, CSA, RoHS, REACH, MIL-SPEC and SAE. Each has specific rules governing virtually every aspect of a part or assembly, even a component as seem-ingly mundane as a label.
It’s important to understand these specifications when selecting a label material, especially if there are testing and qualification requirements at the customer level. Choosing the wrong material could result in having to retest and requalify a new label material, which is costly and inefficient.
Step 5: Printing Technologies
The final factor to consider when choosing a label is the print technology. To achieve the best results, it’s important to match the print technology with the application and environment.
Labels can be preprinted with UV-cured or flexographic inks. Or, they can be printed in-house as needed. The most common in-house printing methods are:
- Thermal transfer.
- Laser, inkjet or dot matrix.
- Direct thermal.
Dot matrix printing can provide good print durability, but low resolution, so it’s usually not the best option when high-quality data or bar codes are required.
Thermal transfer printing is durable and can provide options for crisp print images, but it’s necessary to follow the manufacturer’s recommendations for ribbon compatibility and printer settings.
Selecting the best label materials for your application needs can be overwhelming. These five steps are a great way to identify the most important elements that will affect your label’s success.
While label shopping, look for materials tailored specifically to your application, taking the guesswork out of the process. Label manufacturers offer products to suit a wide range of specific applications, including labels for harsh environments, metalized labels, labels with aggressive adhesive, tamper-evident labels, high-temperature labels, removable labels, and indi-cating labels.
For more information, call 888-250-3082 or visit www.bradyid.com.