Understanding laser texturing
Deriving their name from an acronym for Light Amplification by Stimulated Emission of Radiation, LASERS are electronic optical devices that generate a very intense and narrow beam of monochromatic light by amplifying photons with more energy through collisions with other photons.
While the technology has existed for over half a century, applying it to create textures on materials is a relatively recent development.
Programming for laser texturing begins with saving a texture as an 8-/16-bit grayscale tif or JPEG.
One thing to remember with this process is that the darker the black, the deeper the ablation. The opposite is also true, meaning that the closer to white, the less ablation required.
The advantage of working in the 8-/16-bit grayscale environment is that it provides the user with over 65,000 layers to work with. Traditional chemical processes limit users to working with five to 10 layers only. With each additional layer added the final texture realised is smoother and more defined.
Advantages of laser texturing over chemical etching
Laser blasting/laser texturing is a completely digital process. This provides manufacturers with confidence in consistency, as the part will have the same finish, detailing etc., irrespective of whether it is manufactured in the US, China, Europe or another part of the world.
A fully digital process also enables the creation of new textures that are beyond the scope chemical etching.
Going fully digital to avoid etching provides substantial advantages, such as reducing the need for harsh chemicals and reducing turnaround times. However, there are times when chemical etching makes sense.
Some textures have been patented with the chemical etching process and, until the patent has expired, the process cannot be altered. There also are some situations where extreme roughness/hardness is required. In these cases, chemical etching is the preferred method.
Many manufacturers are adopting a hybrid approach. In these instances, a manufacturer will remove the masking with the laser before moving the workpiece to the chemical processor.
In the case of highly complex moulds, a 5-axis laser system helps to ensure that textures are maintained with perfect control as they go over edges or welding lines.
Differences between laser blasting and laser texturing
Similar in concept to sand or glass blasting, laser blasting is a process for texturing or cleaning a surface. The advantage of laser blasting over sand or glass blasting is repeatability.
With laser blasting, the same finish is achieved every time. Furthermore, manufacturers can ensure that they get the specific surface finish required. Laser blasting also provides the ability to remove milling marks and burrs to ensure a completely smooth surface.
The laser texturing process offers some specific advantages, including the following:
Transparent design process: Laser texturing files can be created from scratch in-house and can include surfaces derived from natural sources via reverse engineering with a 3D scanner. The CAD/CAM software for the laser process allows transition-free patching, UV mapping for applying texture and 3D simulation, resulting in a ‘‘what you see is what you get’’ result for the programmers.
Consistent quality: Laser texturing also allows a user to maintain a smooth and flawless texture across parting lines in a mould tool.
If there are two separate moulds that eventually will be put next to one another, a manufacturer can ensure the texture will transition from one part to the next with a seamless appearance.
Texture and depth flexibility: An additional advantage that laser texturing provides is the ability to have different depths of texture within the same mould. If a user desires two or three different textures within one mould and would them to be set at a different depths, this as simple to achieve by indicating the depth difference while programming the part.
Market segments opportunities for laser texturing
Some of the leading innovative companies in the packaging, PET blow mould, medical, aerospace, microstructures and automotive markets have realised the advantages of this technology. These include the ability to transition to a completely digital environment, exploit the potential of 5-axis laser machining and the ability to create brand-specific textures.
The plastic bottle/blow mould industry has started using laser texturing technology in interesting and unique ways. Some manufacturers in this segment are creating generic bottle forms and then adding different inserts into the forms to achieve different textures. This enables an infinite variety of bottles to be created from a single bottle form, by just by changing the insert.
Bottle manufacturers can also eliminate the traditional steps of milling electrodes and die sink EDM machining bottle caps with a laser ablation process. Not only can the laser texturing system put logos and textures on top of a cap, it can also create ridges along the caps’ sides by employing laser texture machines’ 5-axis capabilities.
For packaging manufacturers, the biggest advantage of laser texturing machines is the ability to create different contrasts, textures and depths. In addition, another feature that is well suited for the packaging industry is the ability to hit parting lines with the utmost accuracy.
Automotive manufacturers have adopted laser texturing as a means to help them distinguish and differentiate numerous aspects of their vehicles i.e. headlights, dashboards, door panels, consoles etc. One of the largest automotive moulds to be textured on a consistent basis is the dashboard.
Because laser texturing machines are able to work with up to 65,000 different layers instead of just five to 10, manufacturers can create and replicate leather grain textures that look and feel like the real thing.
In many cases, headlights require the most unique mould tools for car models with every car manufacturer wanting to have a distinctive and recognisable design. In addition to stylistic and aesthetic design decision, headlights also incorporate more advanced textures due to recent advancements in light bulb technology.
As bulbs have become more powerful, they have also become too bright. In these instances, the lens of the headlight is textured to help diffuse the light.