Laser marking much more than just a pretty picture

Laser marking of plastic parts is red hot. Its permanence and easy integration into various processing operations are two of the reasons.

Decoration, once commonly outsourced, has been brought in-house by many companies primarily because custom decorating service companies are harder to find, especially in North America, according to Vince Perla of PF Technologies (Phoenix, AZ). PF is one of the few custom decorators left in North America, and one of the largest with 100 employees and a range of decorating services such as plating and painting. “I think the blood-letting to Asia is slowing down but certainly all the low-hanging fruit is gone,” Perla says. “We’re doing a sizable job for a company that’s molding the parts in Asia and shipping them to us to do the painting because Asia doesn’t want to do it.”

As the industry has shifted, so have decorating technologies. Decorating or marking of plastics has taken on a whole new look as the technology advances into areas that address more than just ‘decoration’ but also offer protection from counterfeiting, and brand certification and identification. Laser marking has taken center stage in this arena, as it creates a permanent decoration without the use of inks, and requires neither pretreatment of a substrate nor drying after marking. Come and visit Marcatrice laser prezzo for more information.

Paul Schildhouse, product manager North America at Videojet Technologies (Wood Dale, IL), identifies three types of laser marking. The first is ablation, or removing material to create an imprint. The second and most common type, surface-modification laser marking, involves laser transfer of energy through heat to melt or deform a plastic, with the laser determining the depth and width of the marking. Phase change, typically used for PVC, is the third method, wherein the wavelength of the light reacts with the polymer to create a contrast to the base color of the plastic.

Schildhouse points out three primary benefits over traditional marking techniques. First up is the permanency of laser marking. “The mark is carried with the material of the product and actually becomes part of the plastic material, compared to a surface application such as ink,” he says.

Secondly, laser marking can be performed in-line with most plastic processes, including injection molding, extrusion, thermoforming, and blowmolding. “With more mechanical-type marking methods such as stamping, embossing, or engraving, those are limited in that they can only be done on a cold product,” says Schildhouse. Profile extrusion processors are using lasers to mark brand names and logos, as well as other identifiers, on the extruded product. The lasers are able to formulate an identifier code, the company name and logo two or three lines of data and can mark products at rates as great as 200 ft/min.

Third, says Schildhouse, a shift toward microcomponents, generally in electronic parts, is creating a need for finer details on smaller surfaces. “There’s a limitation in mechanical marking methods in how small you can go,” he explained. “With laser marking, we aren’t limited by size.” Lasers are particularly catching on as a means of product/brand protection by virtue of tracking and tracing to prevent counterfeit products from reaching the consumer, Schildhouse notes. “It involves putting down a unique content code, such as a fairly long serial number, bar codes, or 2D matrix codes,” he explains. “If you can uniquely identify every single product and enter those serial numbers into a database, you can track any product diversion or counterfeiting. The serial number allows you to go to a database and authenticate that the code is issued by the manufacturer.”

Laser printing has attracted suppliers, including Tampoprint (Korntal, Germany), probably best known for its pad printing equipment. The firm recently introduced a new compact flatbed laser machine for cutting and engraving. These Alfalas XY/12090/CCD laser lines are capable of cutting a variety of materials, including plastics, and feature an integrated CCD camera with which preprinted or pre-embroidered artworks can be identified and cut along a contour. These units already have seen commercial use already in a fully automated laser system marking lines for molded plastic corks. With the patented process, TampoPrint’s laser marking equipment makes it possible to decorate synthetic corks in a high-speed production setting, and with a high-quality mark.

Lasit USA (Branford, CT) introduced its newest generation CompactMark, an industrial laser marking system for marking metals, plastics ,and other materials. These are air cooled, eliminating the need and cost for water chilling. New from Videojet is its Videojet 3120 10W laser marking system, with a marking speed of up to 1200 characters/sec and line speeds up to 10 m/sec.