This article provides an overview of various engraving laser options. Engraving lasers are ideal for laser engraving or laser marking of a wide range of materials. Laser engraving is the use of lasers to engrave an object. The advantage of an engraving laser is:
- No use of inks. Minimal environmental impact.
- No wear or dulling of tools because an engraving laser contactless works.
engraving laser machines
An engraving laser machine consists of three main parts: a laser, a control unit and a surface. The laser is a drawing tool: the beam emitted by the laser allows the controller to draw patterns on the surface. The control determines the direction, intensity, speed of movement and spread of the laser beam aimed at the surface. The surface is chosen according to the type of material on which the laser can work.
Types of engraving laser machines
There are three main types of engraving machines.
Moving laser optics
The most common is the XY stage where, usually, the workpiece is stationary and the laser optics move in two dimensions, with the laser beam drawing vectors. Sometimes the laser stands still and the workpiece moves. Sometimes the workpiece moves in one axis and the laser in the other.
Example: CO2 engraving lasers
A second genre is for cylindrical workpieces (or flat workpieces mounted around a cylinder) where the laser effectively traverses a helix while pulsing the laser on-off produces the desired raster image.
Example: rotary module for laser engraving machines
Both the laser and the workpiece are stationary and galvo mirrors move the laser beam across the workpiece surface. Laser engravers using this technology can work in either raster or vector mode.
Example: fiber engraving lasers
Focal point of a laser system
The point where the laser beam hits the surface must be on the focal plane of the laser and is usually synonymous with the focal point. This point is typically small, perhaps less than a fraction of a millimeter (depending on the optical wavelength). The laser beam has sufficient energy to process the material only within this range. The energy supplied by the laser changes the surface of the material at the focal point. It can heat the surface and then evaporate the material or peel off the surface. A laser can remove material very efficiently because the laser beam can be designed in such a way that the light energy applied to non-reflective materials such as wood, plastics and, for example, leather can be converted to a large extent into focused heat.
Importance of ventilation during laser engraving
If the surface material evaporates during laser engraving, ventilation by means of blowers or a vacuum pump is almost always necessary to remove the harmful fumes and smoke released in this process, and to remove particles on the surface so that they can continue the laser engraving process. do not disturb.
Engraving laser control
Various patterns can be engraved with an engraving laser by programming the controller so that the laser beam travels a certain path over time. The track of the laser beam is carefully controlled to achieve a consistent material removal depth. For example, crisscrossing paths are avoided to ensure that each etched surface is exposed to the laser only once, so that the same amount of material is removed. The speed at which the beam moves over the material is also important when creating engraving patterns. By changing the intensity and spread of the beam, a specific pattern or image can be put on the material.
Engraving laser machines in production lines
A good example of the application of engraving laser technology in industry is its use in production lines. The laser beam of the engraving laser is aimed at a rotating or vibrating mirror. The mirror moves in such a way that numbers and letters can be applied to the surface to be marked. This is particularly useful for printing dates, expiration codes and lot numbers of products passing along a production line. With laser marking, parts of, for example, metal, plastic or glass can be marked in this way. Older, slower technologies such as hot stamping and pad printing have largely been phased out and replaced by laser engraving.
Engraving laser capabilities – vector engraving and raster engraving
Vector engraving follows the line and curvature of the pattern to be engraved, much like a pen plotter draws by constructing line segments from a description of the contours of a pattern. The introduction of the PostScript description language now allows for much greater flexibility – now virtually anything that can be described in vectors by PostScript-compatible software such as CorelDRAW or Adobe Illustrator can be outlined, filled with suitable patterns, and laser engraved.
Image / raster engraving
With raster engraving, the laser traces across the surface in a back-and-forth slow-moving linear pattern reminiscent of the print head of an inkjet or similar printer. The advantage of rasterizing is the almost effortless “fill” it produces. Most images to be engraved have large continuously engraved areas, as with images. These can be rasterized well.
Materials suitable for laser engraving machines
When marking organic materials such as wood, the surface darkens and a high contract engraving is created.
Hard woods such as walnut, mahogany and maple give good results. On soft woods, the engraving may be less consistent and deeper.
Hard paper, leather and (latex) rubbers can also be processed well with an engraving laser.
By clever use of paper masking tape on the surface to be processed, any deposits and vapor can easily be removed from the material.
Each plastic has specific material properties and a different light absorption. Laser processing can cause immediate chemical changes, melting or vaporizing the material. Additives in plastic such as UV retarders and solvents can influence the engraving result.
Standard cast acrylic plastic, acrylic plastic sheet, and other cast resins are good for laser processing. Styrene (such as in compact disc cases) and many of the thermoforming plastics will tend to melt around the edge of the engraving site. The result is usually less sharp, but still of sufficient quality for certain applications.
For most other plastics it is recommended that you always try a test piece first.
Chlorine-containing plastics (such as vinyl, PVC) produce corrosive chlorine gas during laser engraving, which, in combination with hydrogen, produces hydrochloric acid vaporized in the air, which can damage a laser engraving system and are harmful to health.
Marking metals requires high-density laser irradiation and shorter wavelengths than traditional CO2 lasers (10640nm). Fiber lasers for metal engraving use a wavelength of 1064nm.
The laser evaporates the coating from the metal. This makes it possible to make high-resolution engravings.
Anodized aluminum Usually engraved with CO2 laser machines and fiber lasers for higher resolutions. The laser bleaches the color exposing the white or silver aluminum surface.
Stone and glass
Stone and glass do not easily become gaseous, but microscopic particles are broken down. With the right power and speed, it is quite possible to laser engrave (smooth) natural stone and glass. More recently, for the finer engraving work, we have been using UV laser technology for laser engraving of glass, which produces significantly better engraving results on glass than CO2 or fiber laser machines. The newer UV systems engrave cleanly and clearly without a high degree of microfracturing on the brand surface. Since UV laser systems heat the surrounding substrate less than other laser marking systems, glass substrates are significantly less prone to breakage as a result of the laser marking process. High-quality fill engravings on thin glass and crystal substrates are now regular and reproducible in high volume production environments.
Engraving laser applications
By using a laser, engravings can be made with greater precision than with other techniques. Engravings can be made on both flat (back of watch) and curved surfaces. It is also possible to laser engrave the inside of rings
Works of art
Examples of engravings on a flat surface with a certain depth that are filled with ink or glaze. Artists can digitize drawings, scan or design images on a computer and laser engrave them on materials.
Trophies and Awards
The relatively low cost of laser engraving, driven by automation and inexpensive materials, makes it an ideal solution for personalizing trophies and awards. Personalized laser engraving is fast and can also be used for larger numbers. Readability is sharper than with other techniques.
Engraving lasers can achieve similar results to sandblasting or chemical etching. Photos or images can easily be placed on the front or back of the mirror. With the engraving laser, the silver layer on the back of the mirror is locally removed. After the engraving process is complete, the back of the mirror is “filled” to create contrast.
Industrial engraving laser applications
Traceability of metal parts and products
Equipped with metal parts with logos, type numbers, EAN and QR, DMC codes to be able to follow the parts during the production process or assembly. It is also easy to check in the final product which specific part and version it concerns.
Laser engraving of printing plates and cylinders
Direct laser engraving of flexographic printing cylinders and plates is widely used. Selectively ablate rubber sheet and sleeve materials to produce a print-ready surface without the use of photography or chemicals. The goal is to create sharp relief images for a high-quality reproduction of the process color.
Traceability and personalization of plastic parts and products
Equipped with plastic parts with personalization, logos, type numbers, EAN codes to be able to follow the parts or products during the production process or in the field or to make the products unique. Products can easily be provided with a unique serial number with engraving laser technology.
Laser engraving of PCBs
Printed Circuit Boards are quick to provide non-removable serial numbers and quality control results.
MetaQuip engraving laser product portfolio
MetaQuip has an extensive portfolio of engraving lasers. Laser machines with the capabilities as described above for laser engraving of metals, natural materials such as wood, leather and cardboard and plastics.
In addition to standard machines, MetaQuip also realizes custom build laser machines for specific applications or applications. Contact MetaQuip to learn more about this.