Marking and coding of products, a process now accepted as commonplace, first began with expiration date applications in the food and pharmaceutical arenas. Today products in virtually all industries are routinely coded as part of the manufacturing process. In addition to expiration dates, products are regularly coded with lot codes, real-time dates, barcodes and myriad other information. This enables the manufacturer to trace the product as needed and offers the consumer some measure of security in the purchase. Coding is also an important part of any quality program, whether it is "6 Sigma" or another type of Total Quality Management (TQM) system.

Traditionally, the most common technologies used in the marking and coding of products and packages apply ink, transfer a code or apply a label to create the mark or code. These technologies include: 

• Thermal transfer coders—which use heat transferred to the back of a ribbon that has ink on the front side to print variable information such as date, lot, manufacturing line information, barcodes and real-time data onto individual product packages.

• Mechanical embossing systems—which create marks by pressing or stamping a code into a package.

• Ink jet printing systems—which print on primary packages and cartons by jetting ink through addressable print heads to create a range of data from simple date coding to logos, barcodes and serialization.

• Print-and-apply label systems—which apply pressure-sensitive labels to shipping boxes. The labels are printed using thermal transfer technology and normally contain barcoded tracking and content information.

While each of these methods has advantages that make them suitable for specific applications, recent technological advancements have allowed the entry of lasers into more marking and coding applications, giving manufacturers another option.

Laser coding technology utilizes the processes of ablation and engraving. Ablation is the process of removing material such as a layer of ink on a printed package. The process uses just enough energy to convert the moisture in the ink into vapors and ablates the ink from the substrate. The key is efficient use of the laser's energy to make the process cost effective. Engraving uses an appropriate amount of laser energy to melt or etch a fine groove into materials such as PET (water and soda bottles), polystyrene (PS) and polypropylene (PP). The end result in both cases is a high-quality permanent and immediate code.