In this blog, we explore some of the commonly used materials for laser etching and outline best practices for each of them to get the best outcome for your project.
What is Laser Etching?
Prior to the materials, it should be known that what laser etching is. Laser etching is defined as a process wherein the laser beam removes or alters the material surface in order to make a mark visible. The focused energy of the laser will interact with the surface of the product to produce high contrast markings without the use of any inks or tools.
Laser etching is often confused with laser engraving and laser marking. Though the names sound almost the same, laser etching is in fact a technique that involves the process of shallow markings by either melting the material or vaporizing it, while laser engraving removes a huge quantity of material or even sometimes directly punches out the material. Laser marking is simply the changing of the color of the surface without removing anything.
Materials Commonly Used with Laser Etching
- Metals
- Plastics
- Glass
- Wood
- Ceramics
- Stone
Actually, each of these materials requires special settings and techniques to yield the best results, and thus we will carry on to describe the best practices regarding each.
1. Metals
Laser etching of metals is extremely common in industrial applications, ranging from aerospace, automotive, and medical devices. Metals including stainless steel, aluminum, brass, copper, titanium, and anodized metals are especially suitable for laser etching due to their toughness and ability to withstand high precision.
Best Practice for Metal Etching
- Power and Speed: This is possibly the most significant difference metals have from other materials because they require substantially higher laser power levels than other materials. Of course, this also implies that overpowered settings might easily damage the surface so power trimming is of highest importance. Opt for a medium power setting, and adjust upwards or downwards depending on the material thickness and ideal depth.
- Use Fiber Lasers to Ensure the Best Results: Fiber lasers are actually the best variety of lasers when talking about etching metals. They give precision and speeds at a high level, interacting well with the wavelength of metal surfaces.
- Work with Coated Metals When Available: Anodized aluminum and coated metals will provide better contrast and cleaner finishes. The laser can remove the coating, thus leaving a high-contrast mark. It takes time for metals to get heated up in etching and is prone to error. Cooling methods are applied duly by air blowers and cooling fluids to regulate temperature levels.
- Focus should not be erratic: Metal surfaces should be flat and aligned properly to avoid focus drifting. Focus drifting would cause errors due to uneven results.
2. Plastics
Plastics are one of the most utilized materials in electronics, consumer products, and packaging. Among the popular types of plastic for laser etching include ABS, polycarbonate, acrylic, nylon, and polyethylene among others.
- Etching Plastics Best Practices: Use CO2 Lasers: Unlike metals, plastics generally work well with CO2 lasers because they have the wavelengths that are very efficient in absorbing the heat in plastic material. Plastics are heat-sensitive, and if the laser power is too high, they may warp or melt. It would best be managed using low power and quicker speeds in order not to overheat.
- Material Composition- Compose: Various plastics have varied interactions with lasers. For example, acrylic can be cut and leave the inside clear, sharp edges; and polycarbonate can become frosty. Test different settings to find the best combination for each type of plastic.
- Use Fume Extraction: The etching of plastics gives off fumes that are dangerous. Proper ventilation with good fume extraction systems is essential to help stay safe while keeping the air quality.
- Also keep in mind Laser-Additives: Some plastics are sensitive to the laser, and hence require special laser-sensitive additives to be introduced together with an appropriate etching for greater clarity, more so on light-colored or transparent plastics.
3. Glass
Etching glass is extensively used in interior decoration, awards, and packaging as this process leaves beautiful and permanent marks that do not hurt the material.
Best Practices in Glass Etching
- Focus on CO2 Lasers: Glass etching is mostly done with a use of a CO2 laser inasmuch as the process is clean, frosted marks on the glass surface and does not break or shatter.
- Lower Power Settings: Glass easily breaks, and so power and speed have to be reduced. It is always sensible to start testing by low power levels.
- For the more sensitive designs, a masking layer is typically applied to protect the glass surface and cover stray etching marks by way of masking tape or liquid mask.
- Cool the Surface to Avoid Stress Fractures: Cool down the glass during etching to avoid excess heat that may cause stress fractures or cracks. One can cool the glass using a stream of air or cooling water.
- Test on Different Types of Glass: No glass is universal; float glass, soda-lime glass, and borosilicate glass all have different thermal properties, so testing your combinations for the type of glass you are using is critical.
4. Wood
Many use laser etching on wood for artwork, signs, furniture, and advertising pieces. The different woods include maple, cherry, birch, and MDF, which can produce very interesting differences for laser etching.
Best Practices:
- Wood Etching: CO2 Lasers Work Best on Wood: CO2 lasers are best for etching on wood, and the depth will be quite precise. However, the grain and density will have a lot to do with the power and speed.
- Choose the Right Wood: Hardwood gets marked much better and yields darker and sharper lines. Softwoods can char or burn too easily, so softer woods should be run at reduced power.
- On Your Guard Against Burning: Too much burning is normal to some extent, but can make a mess of the appearance of the completed item. Up the speed or back down on power to reduce overburning.
- Clean Up After Etching: Wood tends to leave behind a lot of debris, so expect that the surface requires cleaning after etching. For this, a soft brush or compressed air may suffice to remove the debris without damaging the etched area.
5. Ceramics
Other good candidates for laser etching are ceramics. As the tiles, pottery, or industrial ceramics withstand great heat, they remain unaffected even by significant etching techniques.
Ceramic Etching Best Practices
- Most ceramics: Use CO2 Lasers - Like glass, most ceramics are highly sensitive to the kind of laser and can produce high contrast marks by just changing the surface glaze.
- Power and Speed Control: High power is always required for etching ceramics, but the risk of overheating and crack formation requires adjusting both power and speed as fast as possible, which ensures clean and sharp etching.
- Try Different Ceramic Types: Glazed ceramics will behave differently than unglazed varieties. Always test your settings in a small test area on the ceramic before applying it.
6. Stone
Stone etching is a popular process in the memorial and architectural markets for deep, long-lasting engravings. Granite, marble, and slate are commonly used materials.
Best Practices in Stone Etching:
- High-Power CO2 Lasers: Stone is dense, so etching needs more power. The harder the stone is, the more power you will need.
- Select Dark Stones for Better Contrast: Dark-colored stones like granite are ideal because they provide better contrast after etching. Light-colored stones can also be used, but then the effect will be less dramatic.
- Do Not go too Deep: It is possible to make deep impressions in stone. Over etching leads to weakening the material. Shallow deep yet detailed should be enough to make the impression of stone survive.
Conclusion
Laser etching is an extremely versatile technique, however to get the best results you must know the material you are operating upon and have the right settings and precautions applied. Whether you're etching metal for some heavy industry application or etching wood for unique crafts, or even etching glass for many decorative objects, the right laser type, power settings, and proper safety measures will ensure a proper completion of an etching job. Best practices will unlock the full potential of laser etching across a wide range of materials.