COGNEX CORPORATION Once you decide that barcodes will be used in your business to improve tracking and traceability, the application of the code is usually accomplished in one of two ways. Codes can either be applied to a package or label using inkjet or thermal printing methods or by permanently marking the code directly on an object via direct part marking (DPM) methods.
Thermal transfer or 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 1D barcodes or ultraviolet (invisible) codes.
Direct part marking
DPM is a process that allows users to mark a code directly on an object instead of printing on a label. For medical devices, automotive parts, 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 codes are considered "permanent" because it would require a significant amount of damage to render a DPM code illegible, unlike labels that can be removed, torn, or distorted by moisture. DPM codes typically include more data than just a part index number; therefore, they often use 2D codes instead of lower bandwidth 1D barcodes.
There are three main types of DPM methods: laser, dot peen, and chemical etching. 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.
| Code Image on Metal | Marking Type | Description |
| Laser | Laser marking systems typically use fiber lasers to engrave Data Matrix codes or other 2D code symbologies on the part. | |
| Dot peen | 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. |
Download the Introduction to Barcode Reading Guide to learn more about barcode printing and marking methods.
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Cognex Corporation published this content on 06 October 2021 and is solely responsible for the information contained therein. Distributed by Public, unedited and unaltered, on 06 October 2021 04:15:05 UTC.
