What are the applications of laser marking on plastic products?

With the development of the automobile industry, plastics have become an important part of automobiles. In addition to handles, air intake grilles, instrument handles, air intake grilles, dashboards, bumper shell interior and exterior trims, there are more invisible plastic parts, such as fuel tanks, battery boxes, intake manifolds, engine hoods, etc. The permanent identification of these parts is an indispensable key link in the traceability of vehicle quality. In order to facilitate the traceability of production batches and inventory management through identification information, these parts need to be marked with clear codes or QR codes. Compared with traditional marking, such as traditional printing, screen printing, heat transfer, embossing, ink printing or embossing, these surface marking effects will cause the marking content or pattern to be blurred or worn after long-term use, and even cause the material surface to fall off. At the same time, the production environment of the plastic marking factory causes air pollution due to ink and other reasons, which has a great impact on the health of workers and the working environment. Laser not only solves the above difficulties and shortcomings, but also has a significant effect on marking.

Laser Marking has a flexible processing method, which can quickly and clearly mark the processing pattern on the plastic surface. During laser marking, the same product and the same position can be repeatedly accurately marked. If the user has requirements for marking depth or color, it can be repeated many times, and offline or on-the-fly marking can be achieved to improve marking continuity, thereby realizing automatic or semi-automatic processing.

Laser plastic marking can be divided into four different marking types according to the material surface reorganization or color change:

Blistering, engraving, carving and color change. Of course, many plastic samples will not change without adding auxiliary agents after processing.

1. No marking by shooting through

There are also many transparent or translucent plastics, and the laser will penetrate the material without marking.

However, there are two special materials, namely polycarbonate (PC) and PVC (PVC), which are transparent to the naked eye, but even under extremely low-intensity laser energy, these two materials will carbonize, resulting in clear markings.

2. Bubbling

For some plastics, when the laser energy is low, it is not enough to carbonize the material, but only decomposes some components on the surface of the material, produces gas, and causes the plastic to bubble. This foam has a slight color difference from the base color of the material, thus obtaining a light-colored mark.

3. Engraving sinking

When the laser peak is high or the material melting point is low, the local temperature on the material surface is much higher than the mass melting point, and structural reorganization corrosion or gasification will occur on the material surface. For example, CO2 laser engraving on acrylic material, pump laser engraving on silicone.

4. Engraving Depression

Color Change When the laser energy is high, the plastic is over-carbonized by laser irradiation, and spots of different sizes and different black depths appear on the material. For example, styrene compounds begin to react and carbonize under medium-intensity laser irradiation. When the laser intensity continues to rise, excessive carbonization and cracks are prone to occur.

5. Color change (short wavelength)

Sufficiently short laser wavelength radiation can separate plastic molecules, resulting in color change, which is the most ideal effect. However, it is often necessary to add an appropriate amount of additives to the plastic to achieve a beautiful effect.