Industrial Barcode Reading

1-D and 2-D Code Printing and Marking Methods

Every code application begins with collecting information from a central database, which often includes the origin and other manufacturing data, and then applying that data to an object. The application of the code is usually accomplished in one of two ways: by applying the code to a package or label, usually using inkjet or thermal printing methods, or by permanently marking the code directly on a part via direct part marking (DPM) methods such as dot peen, chemical etching, or laser marking.

Thermal Transfer and Inkjet Printing

Inkjet printers are most commonly used for printing the code on a package, label or other material. Inkjet printers create the barcode by propelling droplets of ink onto a substrate such as paper or plastic. Thermal transfer technology is typically used for printing labels. This process heats up the print head and applies ink directly to the label. Inkjet and thermal printing are often used to print 1-D barcodes.

Direct Part Marking

For many applications, such as medical devices, automotive and other durable goods where traceability and liability protection at the component level are important, DPM methods offer a longer-lasting alternative compared to printing methods. DPM solutions will typically include more data than just a part index number; therefore, they often use 2-D codes instead of lower-bandwidth 1-D barcodes.

Depending on the material being marked, each method has its own strengths and weaknesses. For metal parts, laser-marking systems offer high-throughput permanent marks but are costly to install. Dot peen marking heads are less expensive but they wear down, which can compromise the mark. Interestingly, some vision-enabled code reading systems can monitor the quality of printers and DPMs, alerting machine operators to clogged print or worn marking heads.

Laser Marking

Laser marking systems typically use fiber lasers to engrave DataMatrix codes or other 2-D code symbologies on the part.

Dot Peen Marking

Dot peen marking systems, generally considered the most cost -effective option; use an oscillating stylus to press into the metal, creating a divot.

Chemical Etching

Electrical chemical etching uses a sodium-based solution combined with a pulsing low-voltage electrical current. The charged solution dissolves the metal, which is then extracted through a special stencil.
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