Laser Engraving Aluminum Overview: Everything You Should Know

Laser engraving is an excellent process for high-quality product finishing and branding. It involves using a laser beam to produce permanent, high-quality markings on material surfaces. The laser beam vaporizes the material, creating indentations or markings on its surface. Laser engraving can be applied to various materials like aluminum. Aluminum is an ideal candidate for laser engraving due to its corrosion resistance, light weight, durability, and low cost. Laser engraving on aluminum produces permanent markings with clarity and sharpness.

This article explains laser engraving aluminum and all that it entails you should know. We will discuss its brief introduction, pros and cons, three typical aluminum using laser engraving, and a comparison between the laser etching, etc. Let’s get into it!

What is Laser Engraving Aluminum?

Laser engraving aluminum is a process that utilizes a laser beam to create markings on the surface of aluminum products. The laser beam causes the aluminum to melt and evaporate, creating depressions on its surface. These depressions form the engraving patterns or designs specified by the user. Laser engraving aluminum can mark serial numbers, QR codes, logos, brand names, and other information. Permanent laser marking facilitates identifying and tracking different parts, items, and components.

Permanent laser markings are left on the surface of aluminum permanently. This is particularly essential for aluminum, as aluminum parts are exposed to various abrasion and surface treatments. Regardless of how long a component lasts or how many processes it undergoes, engravings do not wear out, tear, degrade, or become discarded. As a result, laser engraving is an appropriate marking method for parts subjected to further severe treatments throughout the production process, such as sandblasting and shot blasting. 

We can find laser-engraved parts for their operations in many fields, including the automotive, medical, jewelry, energy, and aeronautics industries. Using this method, project managers and business owners can brand their products. Various engraving techniques can be used to engrave texts, serial numbers, logos, codes, and other things into various materials.

How Does Laser Engraving Aluminum Work?

In aluminum laser engraving, a strong beam from a laser engraver works as the chisel, vaporizing particles from the metal surface to incise deep markings. The laser engraver should emit sufficient energy so that beam can excite the surface material to its vaporization temperature, which is 4,221℉ or 2,327℃ for aluminum. To avoid the formation of liquid residue, vaporization occurs in a matter of seconds.  

The laser engraving processes generally operate on the principles of sublimation. Sublimation is the sudden transformation from solid to gas without passing through the intermediate state of liquid. This is why you will never see materials melt under a laser machine. The particles vaporize when laser beams contact its surface, revealing the engraved region. You can feel the depth of the cavity if you touch the engraving. 

Laser engraving aluminum is superior to drilling since it does not alter the metal’s properties or look. It marks the surface of aluminum without removing the surplus material. Modern laser marking systems have the standard features of a fume extraction device and an air knife. Fume extraction prevents hazardous fumes from entering the workplace, while the air knife protects the laser’s lens.

Pros and Cons of Laser Engraving Aluminum

Laser engraving produces longer-lasting, high-quality markings than etching, ink stamping, or other methods. However, it also necessitates a high level of operator skill and has different lead times depending on the material. The following will explore the cons and pros of aluminum laser engraving.

Pros of Aluminum Laser Engraving

• Laser engraving can achieve marking speeds of up to 1000 characters/second with precision down to 0.001 mm, allowing mass production of aluminum components.
• Laser engraving produces permanent markings resistant to wear, tear, and fading.
• Laser engraving requires no inks, solvents, or tool changes. The only replacement parts are the laser tubes or diodes, reducing operating and maintenance costs. 
• When compared to mechanical engraving, this method is more efficient.
• More accurate markings as compared to processes such as ink stamping.
• Eco-friendliness improved in certain machines (as less waste is emitted into the environment).
• Reduced chance of fake components entering the downstream supply chain.

Cons of Aluminum Laser Engraving

• The laser beam can produce burrs on the edges of the engraving, which require smoothing.
• Laser engraving necessitates a high operator ability, particularly when designing and setting up laser equipment. 
• Aluminum requires high-power lasers, typically rated between 50 to 120 watts, for effective engraving. These industrial laser systems have large equipment footprints and higher costs.   
• Production speed varies depending on the density of the material, and it might consume a lot of energy. Both of these can increase costs.
• Some laser cutters emit harmful fumes. Fumes may be a significant source of pollution in the environment.

Typical Aluminum Used in Laser Engraving

Laser engraving is one of the quickest and most reliable processes of creating markings on materials. Aluminum is a popular and commonly engraved metal. The typical aluminum used in laser engraving includes bare aluminum, anodized aluminum, and powder-coated aluminum.

Bare Aluminum

Bare aluminum is uncoated or untreated aluminum in its raw form. It has not been subjected to any surface finishing process to change its properties, texture, or appearance. Due to the manufacturing process or handling, bare aluminum may not have a smooth or even surface, rendering it vulnerable to oxidation and other forms of corrosion. This type of aluminum is typically utilized in areas where appearance and corrosion resistance is not the most important, such as electrical components, construction materials, and heat sinks. Bare aluminum can also function as a substrate for further surface treatments, including anodizing or painting to better its properties.

Anodized Aluminum

Anodized aluminum is a type of aluminum that has an anodized exterior coating through the process called anodizing. Anodizing is an electrochemical process that applies an anodic oxide finish to a metal surface.

Anodizing forms a stable aluminum oxide layer completely integrated with the underlying aluminum substrate. This layer is stronger and more durable than bare metal. Because this layer is intact with the aluminum substrate and not applied to the surface, it is resistant to chipping, peeling, scratching, and flaking. 

This layer’s structure may be very porous, allowing dyes, paints, lubricants, and adhesives to be applied to the anodized part. Finally, this layer considerably improves the raw aluminum’s corrosion and weathering resistance, allowing it to tolerate hard situations.

Powder-coated Aluminum

Powder-coated aluminum refers to a kind of aluminum that has been treated with powder coating. Powder coating is applied via an electrostatic spray deposition method. Using a powder spray tool can precipitate the coating particles onto the aluminum. Typically, the composition of the coating material combines several plastic polymers such as acrylic, epoxy, polyurethane, etc. 

Additionally, these ingredients are frequently mixed with extra pigments, flow modifiers, curing agents, and additives to ensure that the coating is applied evenly to the surface of the aluminum. Powder coating gives a long-lasting, robust finish that comes in various colors.

3 Types of Lasers Used in Aluminum Engraving

Now that we have briefly introduced bare aluminum, anodized aluminum, and powder-coated aluminum, let’s look at the lasers that will work best for their engraving. Generally, there are three common lasers, including CO2 laser, diode laser, and fiber laser. Let’s take a closer look at them.

Fiber Laser

Fiber lasers operate at a wavelength that is more reactive to metals. They effectively produce a high-contrast, long-lasting mark without interfering with the parts’ integrity. Although the upfront cost of a fiber laser is 3 to 4 times the CO2 laser and 15-20 times the diode laser, they are more durable, faster, and have less operational cost. 

As a result, they are commonly used for industrial part marking applications. However, fiber lasers cannot engrave diverse materials like nonmetals. 

CO2 Laser

The low upfront cost is one of the reasons you can employ a CO2 laser. More importantly, it can engrave and cut a variety of materials. Not only can aluminum be engraved with CO2 lasers, but these lasers can also be used on non-metallic parts made of acrylics, wood, and natural stone. Therefore, they are more generally employed by producers with a wider range of materials.

Diode Laser

A diode laser is the most economical method for engraving anodized and powder-coated aluminum. And it costs lower than a CO2 laser. Additionally, a diode laser can engrave solid wood, plywood, acrylic, ceramics, glass, stone, metals, and so on.

Laser Engraving Bare Aluminum

Regarding laser engraving bare aluminum, you can use fiber laser and CO2 laser. A fiber laser may be engraved directly on bare aluminum, but a particular pretreatment is required if you use a CO2 laser. Generally speaking, the diode laser is not feasible for engraving bare aluminum because this requires proper pretreatment and many passes for satisfactory results.

Given its wavelength, fiber laser does not necessitate any pretreatment or coating. It has a wavelength ranging from 780 to 2200 nm and is absorbed by most metals, including aluminum. Therefore, fiber lasers can engrave metals without any precondition.

In terms of a CO2 laser, it has a higher wavelength, often approximately 10,600 nm. Usually, its wavelength is reflected by bare aluminum and other metals. However, it reacts well with nonmetals. As a result, if you wish to engrave bare aluminum with a CO2 laser, you must first apply a thin coating of metal marking compound. Following the application of the coating, you can engrave the metal. Once the engraving is completed, the coating may be removed with water.

Similarly, if you want to engrave bare aluminum with a diode laser, applying a metal marking compound in advance is also necessary. Because the engraving will be very light and hardly visible, you must do many passes, such as 10-12 passes with a 10W laser, to achieve noticeable results. Consequently, time-consuming makes the diode laser become not a viable solution for engraving bare metal.

Laser Engraving Anodized Aluminum

CO2, diode, and fiber laser are acceptable for anodized aluminum. You may utilize any of them and get the greatest results with minimal effort. Even if you use CO2 or diode laser to operate laser engraving on this type of aluminum, pretreatment is not required. The main reason is that the oxide layer may absorb the wavelength of CO2 and diode. This allows you to engrave on anodized aluminum directly.

But in comparison, a diode laser is still the most affordable for anodized alumina. The diode laser works well; you can achieve amazing results in only one pass. However, take in mind that the thickness of the coating on anodized materials varies. A thicker coating requires increasing the power of the laser.

Laser Engraving Powder-coated Aluminum

Like anodized aluminum, CO2, diode, and fiber lasers are also suitable for laser engraving powder-coated aluminum. As it already has a coating, no pretreatment is necessary. Because of the powder coating, laser beams from CO2 and diode lasers are absorbed, making the material readily engraved.

Difference Between Laser Engraving and Laser Etching

Laser etching and engraving are popular in various sectors to mark stamps, text logos, barcodes, etc. They share similarities, yet they also have distinctions.

Working Principle

Laser engraving removes a top layer of material from the surface of an object to create marks or designs. Laser engraving uses high-power lasers to vaporize material from the surface layer, creating a visible and palpable cavity.

In contrast, laser etching metal entails melting a specific region of the metal surface by heating it with a lower-power laser beam. The laser beam’s heat melts the surface, causing it to stretch or expand. This motion produces a seen and felt raised mark.

Depth of Marking

Laser engraving removes more material and creates deeper markings than laser etching. The laser etching process doesn’t involve any form of material removal. It does not create deep marks like laser engraving.

Engraved marks can be up to 0.5 mm deep or more, while etched marks are typically less than 0.2 mm deep. Deeper marks provide higher durability but reduce precision.

Material

Laser engraving and etching may make high-quality, permanent markings on various materials. Yet, laser engraving is best suited for marking hard, flat surfaces, whereas laser etching works perfectly on softer materials or curved surfaces.

Engraving is typically used on harder materials like metal, glass, and wood to create deep, precise markings with high contrast and sharp edges. Etching is typically used for creating superficial designs or markings on softer materials like plastics, wood, and acrylic. 

Durability

Laser engraving leaves a more permanent and long-lasting mark than laser etching. Laser engraving technology is generally useful for components subjected to a lot of wear.

Production Volume

Because laser etching is faster and more efficient, it is more appropriate for higher production volumes. Laser engraving, on the other hand, takes more time and is hence better suited for smaller production runs.

Surface Finish

Laser engraving produces a rough surface with visible pits and grooves. Laser etching results in a smoother matte finish as it does not cut as deeply into the material. Engraved areas often require re-machining or polishing.

Cost

Laser engraving equipment is typically more expensive, especially for high-power systems. Laser etching can be achieved using lower-cost laser markers. Operating costs are higher for engraving due to greater material removal and electricity consumption.

Tips for Perfect Laser Engraving Results

Laser engraving on aluminum is a widespread process that produces permanent markings with clarity, sharpness, and speed. Here are some useful tips for achieving perfect laser engraving results:

• Choose a suitable material for laser engraving, like aluminum, stainless steel, brass, or gold. Woods like maple, oak, and MDF also work well. Some plastics can be engraved, but check material compatibility.
• Select an alloy and thickness supported by your laser for metals. Aluminum should be 1 mm thick at least, while stainless steel can be 0.5 mm or more. Very thin or thick materials reduce quality.
• Clean and degrease the workpiece. Any coatings, oils, or debris on the surface will damage the laser optics and affect focusing, reducing engraving quality.
• Focus on the laser precisely for optimal results. Refocus as needed for contours or recesses in the workpiece. Defocusing causes blurry, undefined marks.
• Securely fasten the workpiece to a level engraving table or fixture. Unstable or uneven positioning results in poor laser focusing and messy results.
• Choose a laser power, speed, and frequency that suits the material and desired mark depth. More passes at lower power produce cleaner results than higher power. Multiple lighter passes are preferred for deeper engraving.
• Prepare the design. Ensure the engraved design or artwork is properly prepared and appropriate for the material used. This can include tweaking the design for the desired results, selecting the appropriate font, and properly aligning the design.
• Test and refine. Before engraving an important piece, it’s a good idea to test the settings on a scrap piece of material to refine the settings and ensure the desired results. This can also help prevent costly mistakes or errors.
• If needed, apply a sealant to finished engravings to prevent oxidation or corrosion and improve durability. Sealants also enhance contrast for improved visibility.
• Clean away debris from the workpiece and engraving table after engraving. The equipment or work surface residue can damage components or the next workpiece.

Summary

Are you searching for a reliable method to personalize your aluminum products? Laser engraving aluminum is the right solution you need. Laser engraving aluminum is a process that uses lasers to create permanent marks like designs or text onto aluminum substrates. The markings are usually highly durable and long-lasting. Laser engraving aluminum is highly versatile and perfect for various automotive, medical, jewelry, energy, and aeronautics applications. Additionally, if you want to personalize promotional products, create signage, or embellish industrial parts, laser engraving aluminum offers high-quality, long-lasting results.  

Laser engraving is ideal for completing the aluminum or other material parts you wish to mark. LEADRP has advanced technology and provides skilled and professional laser etching, engraving, cutting, and other machined parts finishing services. Our equipment can effortlessly etch or engrave on various materials and surfaces.

Contact LEADRP immediately, and let us help you bring your idea to life.

Reference

Aluminum Laser Engraving: All You Need to Know – From xTool