The Right Choice of Label Material is a Critical Component of Successful IUID Marking

By Ken Koldan, New Business Development Manager, FLEXcon

The use of IUID (Item Unique Identification) is growing as an asset management tool, not only by OEMs to fulfill the mandates of the Department of Defense (DoD), but increasingly by other federal agencies, state governments, police departments and commercial enterprises that see the advantages of IUID for asset tracking, inventory management and related uses.

The advantages and success stories of IUID are well known and documented. The programs that have used the IUID system have been shown to lower their program risk significantly.

Information is readily available on the DoD Web site and elsewhere on such topics as the required content of the two-dimensional bar code IUID label and its environmental parameters. Also readily available are strategies for optimizing a Date Management System.

Development of the Data Matrix Symbol
In 1984, the Automotive Industry Action Group published an application standard for shipping and parts identification labels which consisted of four “stacked” Code 39 bar codes. These stacked bar codes contained part number, quantity, supplier and serial number. Intermec Corporation introduced the first truly two-dimensional bar code in 1988 when they announced Code 49.

The IUID Data Matrix from Siemens Energy and Automation group was co-developed with the DoD. It is a 2-D matrix code designed to pack a lot of information in a very small space. A Data Matrix symbol can store between one and 500 characters. The symbol is also scalable between a 1-mil square to a 14-inch square. Therefore, a Data matrix symbol has a maximum theoretical density of 500 million characters to the inch. Actual density will, of course, be limited by the resolution of the printing and reading technology used.

The actual material on which you put this IUID Data Matrix has a direct impact on the reading technology and the data accuracy. There is, however, a scarcity of guidance on the choice of label material itself. The label material requirement is that the machine-readable information (i.e., IUID Data Matrix) must be readable from initial acquisition (e.g., signed Material Inspection and Receiving Report or DD250 as it is commonly called) to final disposition, including storage. This is a critical issue, in that the label material must be sturdy enough to receive highly detailed thermal transfer printing of the 2D Data Matrix symbol on what are often tiny labels, while providing a level of durability that will last the lifetime of the marked item.

This article provides logistics manager, subcontracts managers and others with the basic considerations for making an appropriate choice of IUID label material to support program objectives and meet DoD mandates. By “label material,” we mean the label substrate, adhesive, top coating of the substrate (if needed for optimal printability) and the release liner (the paper or film layer that protects the adhesive and is removed before application of the label to the item being supplied to DoD).

Our advice assumes the reader has implemented a successful data management system and understands the parameters of the DoD requirement, but would benefit from basic information on label material considerations.

Choosing the Best Marking Option
A primary consideration for marking of items being sold to DoD is whether direct or indirect IUID marking is called for. In general, direct marking of the item, which is accomplished by creating the Data Matrix bar code directly on the item surface usually via dot peen or laser etching, is appropriate when the item will be exposed to the harshest conditions, such as in battlefield situation or in extreme climates (extreme chemical washes, pressure washers at 400 psi and very long-term frigid temperature, for example).

Although it is the most robust marking solution, direct marking of the item is time-consuming and relatively costly over the lifecycle. And, it is not always required. Indirect options include printed thermal label, ink applied to the item surface itself or data plate. The majority of IUID applications can be successfully handled via indirect marking on thermal-printed label, even in circumstances where environmental stresses are moderately challenging.

While data plates carrying the IUID Data Matrix symbol may be plastic, metal or similar hard material, an IUID label is most appropriately achieved with pressure-sensitive polymeric film. Pressure-sensitive (self-adhesive) polymeric film has advantages over paper for such IUID labels due to its significantly greater durability, coupled with exceptional printability via thermal transfer (the most common printing technology for IUID labels) for both human- and machine-readability of the symbol and its embedded information. The variety of films, such as vinyl and polyester, and variety of adhesives allow a labeling product to be precisely matched to the application requirements.

The Pressure-Sensitive Film “Sandwich” or Label Material
The flexible nature of pressure-sensitive film—both literally and figuratively—gives design engineers limitless possibilities in meeting product development requirements in electronics and other industries. In many cases, the wide-ranging characteristics and potential of pressure-sensitive film can be the catalyst for new product designs.

The reason is that it comprises four layers of widely varying material components—film, adhesive, top coat and liner—with options in each category that can be infinitely combined to best meet the application need. By combining various component layers, design engineers can specify a pressure-sensitive film to suit a wide range of product applications for various lifecycles or duty cycles.

Establishing the Performance Requirements
When seeking a labeling solution that will perform to the DoD standard, the Logistics Manager or other responsible party should note that the label material supplier can provide an appropriate labeling product only when the specific performance requirements for the label are known and defined up-front. Key factors to be considered include, but are not limited to:

• The expected lifespan of the item being marked
• The environmental conditions the label and marked item will face during its lifetime (such as UV exposure, abrasion, chemicals, extreme heat, extreme cold, cleaning agents and so forth)
• The nature of the surface (rough, smooth, metal, wood, low surface energy plastic, etc.) to which the label must adhere
• The dispensing process by which the IUID label will be affixed
• Other state, federal or industry specifications beyond DoD requirements that the label must meet
• The printing process being used to produce the IUID label (most common is thermal transfer, although other print technologies may be employed)

When discussing IUID label needs with your label materials supplier or your printer, the more detailed your answers to such questions, the greater the likelihood of the proper labeling material choice and, thus, the success of the label in meeting DoD requirements.

For example, assume the item being supplied to DoD is an electronic device which has an expected life of five years, will be used both indoors and outdoors, features a smooth painted metal surface on which a thermal transfer-printed IUID label will be affixed, and will be exposed to UV and occasional temperature extremes. By knowing such criteria ahead of time, the label material supplier may recommend a construction that features a 3-mil polyester base film (polyester is noted for its durability), an aggressive high-performance acrylic adhesive that will hold its bond to painted metal even in temperature extremes, and a UV-resistant polyester over-laminating film to protect the label. The asset management subcontractor/task-owner then has the ability to affix the label and significantly reduce the risk of nonconformance and satisfy the specification in MIL-STD-130 ver. N.

The goal of sharing label performance requirements up front is to optimize the solution to meet the requirements and lower the risk of the program and total cost of ownership.

Choosing the Right Supplier
Whether you are planning to work directly with a label material supplier or indirectly through your label printer, there are certain characteristics to look for in a label material supplier to maximize your chances for success. The supplier should:

• Offer off-the-shelf labeling products that are pre-tested on specific surfaces to assure the necessary durability and other performance characteristics, and should provide data on the expected performance of each product on those surfaces
• Be able to create a one-of-a-kind custom labeling product if your application requirements are unique. Your IUID labeling application may, for example, require affixing of a label to an unusual surface in terms of texture, material and/or curved shape, or may require reliable performance in unusually harsh conditions involving abrasion, moisture or cleaning solvents
• Offer scalability/flexibility to meet your changing business and operational requirements and to provide the most cost-effective solution, recognizing that many suppliers are in competition for DoD contracts and cost considerations are of increasing importance
• Contribute to the lowering of your Total Cost of Ownership of the program and the Total Applied Cost of your supply chain, thereby effectively lowering the total overall risk and cost of the IUID program
• Meet your program’s Lifecycle Statement of Objectives and Key Performance Parameters

Lower the Risk of the Program
What can go wrong if you or your label printer choose an inappropriate material? It can just simply fall off or fade away.

With the wrong material, problems such as poor print quality or production slowdowns can occur during the printing of the bar-coded labels. During end-use, the label graphics can fade due to wear and tear, abrasion, moisture or UV exposure, which can result in flawed scans and inaccurate readings of the Data Matrix symbol. The label can tunnel, flag or peel before the marked item’s lifespan is complete, defeating the purpose of the “cradle to grave” DoD mandate.

The right label material selection is a critical step that should not be overlooked for the total IUID solution. In order to minimize total program risk, a label material assessment task should be included in any program work breakdown structure.

When you’re ready for such an assessment, let Industramark lead you through the process. By working with expert film and adhesive suppliers like FLEXcon, we can help ensure that you’re using the right label and the right materials for the job at hand.