"Direct Marking" allows products to be marked directly without the use of labels, tags, etc., when displaying product identification or expiration dates. There are many marking methods on the market, but the advantages of "direct marking" are attracting attention when accurate production information management is required, and the use of laser marking machines is increasing. Laser marking machines are used not only for marking, but also for resin cutting, deburring, and other processing.
Sexual laser processing applications
Cutting and processing of films
Laser markers are often used in processing applications such as films and diaphragms. Compared to the method of making a stencil and then making holes, the laser marker has the advantage of a non-contact cutting technology that makes it easy to change the design and does not wear out the stencil without incurring operating costs.
Deburring of IC chips
A laser marker can be used to remove burrs from the lead parts. Because the laser only scans the IC with high accuracy, it can be deburred without causing damage to the inside of the package. In addition, since the non-contact method does not damage the lead frame itself, it can be processed with high quality without deformation.
Patterning of ITO films
The surface layer can be patterned using a laser. In the past, wet etching, which mainly used chemicals, is now a dry etching method using a laser marker to improve processing accuracy and reduce environmental impact.
The principle of resin marking and processing
Reflects, absorbs, and transmits light
All objects are "reflected", "absorbed" and "transmitted" when they receive light. This phenomenon has also become a very important element in laser marking and laser processing. For the energy "1" of the received light, the proportion of "reflection", "absorption", and "transmission" is called "reflectivity", "absorption", and "transmittance", respectively, and the relationship is as follows.
Reflectance + Absorption + Transmittance = 100%
The greater the reflection and "penetration", the more the temperature of the object cannot rise, and the more difficult it is to process. The more "absorption", the higher the processing efficiency.
The main marking process
- Stripping of the printed surface: This method contrasts with the color of the substrate by stripping off the coating or printing on the surface of the workpiece (e.g., instrument panel switches for automobiles). When changing the design, it is necessary to change the template if it is a conventional printing method or stamp, but with a laser marker, it is possible to flexibly operate it by simply changing the program.
- Surface layer peeling: Cutting is performed using a laser marker. In the past, machining was performed with tools, which was difficult to adjust and time-consuming to switch between different varieties. In addition, there are costs associated with replacing the tool, and there is a risk that the tool will remain inside the product in the event of a failure.
- Discoloration: This method irradiates a laser on the resin to discolor the workpiece itself (e.g., LSI large-area marking). By irradiating a laser, color can be generated without engraving resin, and marking can be performed to minimize damage to the workpiece. In addition, large areas up to 330 × 330 mm can be printed uniformly, reducing the equipment cost of the mechanical mechanism required to transport workpieces in the past.
The principle of resin discoloration
Foaming
Once the laser is irradiated, the thermal effect creates bubbles within the substrate. The vaporized and evaporated bubbles are enclosed in the surface layer of the substrate in a whitish and raised state. Especially in dark substrates, the clarity is better, and it will change to a "lighter substrate color".
Concentrate
As soon as the "substrate" absorbs the energy of the laser, the density of the molecules rises due to this thermal effect, and when concentrated, it becomes dark.
Carbonization
If higher energy is continuously irradiated, the polymers of the materials around the "substrate" will be carbonized and blackened.
Chemical changes
In the "pigment" composition of the substrate, metal ions must be present. By irradiating the laser, the structure of the ion crystal changes and the amount of hydration in the crystal changes. Finally, its composition itself undergoes chemical changes, and color development can also occur due to the increase in pigment concentration.
Be the first to comment