Laser cutting stands as one of the most transformative technologies in modern manufacturing. From intricate medical implants to large-scale industrial components, its ability to deliver clean, precise, fast cuts in a vast range of materials has made it an essential tool across countless industries. At its core, laser cutting is a thermal separation process that uses a highly focused, high-energy beam of light to achieve results that are often impossible with traditional mechanical methods.
The power of this precision laser material processing technology, however, is only fully realized when it is paired with equally precise motion control. The ability to guide the laser beam along a complex path with micron-level accuracy and repeatability is what defines the quality, speed and capability of any laser cutting system. This article will explore the fundamentals of the laser cutting process – including its applications, advantages and critical reliance on motion technology.
Laser cutting is a non-contact fabrication process that uses a focused laser beam to cut through materials. The laser generates an intense beam of light that is directed to the workpiece by a series of optics. When this focused energy hits the material, it is absorbed and heats the material in a very small, localized area to its melting or vaporization point. A jet of assist gas is used simultaneously to eject the molten or vaporized material from the cut, creating a narrow channel known as a "kerf."
A motion control system, such as a CNC-driven stage or a high-speed galvanometer scanner, moves the beam or the workpiece along a programmed path to create the desired shape or profile. The result is a highly precise, clean cut with minimal thermal damage to the surrounding material.
The laser cutting process works by concentrating optical energy to achieve a very high-power density. The process can be broken down into a few key steps:
Beam Generation: A laser resonator (the "source") generates a high-intensity, coherent beam of light. Common industrial lasers include CO₂, fiber and Nd:YAG types, each with a specific wavelength suited for different materials.
Beam Delivery: The beam is guided from the source to the processing head using a series of mirrors or a fiber optic cable. The processing head contains a focusing lens that concentrates the beam onto a tiny spot, often fractions of a millimeter in diameter.
Material Interaction and Removal: As the focused beam strikes the workpiece, its intense energy is absorbed, causing the material to rapidly heat, melt and vaporize. The choice of laser parameters (power, pulse rate) and material properties determines whether the primary removal mechanism is melting or vaporization.
Assist Gas Ejection: A coaxial nozzle delivers a jet of assist gas (such as oxygen, nitrogen or argon) into the cut. This gas jet forcefully ejects the molten and vaporized material from the bottom of the kerf. For laser cutting steel, oxygen is often used as it creates an exothermic reaction that adds energy and increases cutting speed. For materials where a clean, oxide-free edge is desired, an inert gas like nitrogen is used.
Controlled Motion: A laser cutting machine uses a sophisticated computer numerical control (CNC) system to create relative motion between the laser head and the workpiece. This motion guides the cutting process along the programmed vector path to create the final part geometry. The precision and dynamic performance of this motion system are critical for achieving accuracy, smooth edges and high throughput.
The versatility, precision, and speed of laser cutting have led to its adoption in a wide array of industries and applications. The list of uses of laser cutting is extensive and continues to grow as the technology evolves. Some of the most common applications include:
Sheet Metal Fabrication: This is arguably the largest application area. Lasers are used extensively in job shops and large manufacturing operations to cut parts from sheets of steel, aluminum, stainless steel and other alloys for automotive, aerospace, electronics and general industrial use.
Electronics Manufacturing: In the electronics industry, lasers are used for high-precision tasks such as depaneling printed circuit boards (PCBs) and cutting intricate patterns in flexible circuits. The non-contact nature of the process is ideal for these delicate components.
Medical Device Manufacturing: The ability to create tiny, precise features with a clean, burr-free finish is critical for medical devices. Lasers are the primary method for cutting the complex filigree patterns of cardiovascular stents and for fabricating components for surgical tools and implants.
Plastics and Polymer Processing: Lasers are highly effective for cutting a wide range of plastics and polymers. Applications for laser plastic cutting include trimming automotive interior components, creating signage and fabricating acrylic displays.
Textiles and Fabrics: In the apparel and automotive industries, lasers are used to cut fabrics for everything from custom clothing and lace to car seats and airbags, offering speed and the ability to seal edges to prevent fraying.
Art and Architecture: Lasers are used to create intricate decorative panels, architectural models, and custom signage from materials like wood, acrylic and metal.
When asked what are the advantages of laser cutting, it becomes clear that the technology offers compelling benefits over traditional methods like mechanical cutting, punching or waterjet cutting. The primary advantages of laser cutting include:
High Precision and Intricate Detail: Lasers can create extremely fine features and sharp corners with tolerances measured in micrometers. This allows for the production of complex parts that would be difficult or impossible to make with other methods.
Excellent Cut Quality: Laser cutting typically produces a smooth, clean edge finish with a very narrow kerf width, often eliminating the need for secondary finishing operations.
Minimal Heat-Affected Zone (HAZ): The laser's energy is highly localized, which minimizes the amount of heat transferred to the surrounding material. This results in less thermal distortion, which is especially important when cutting thin materials or features close together.
No Mechanical Contact: As a non-contact process, there is no physical force exerted on the workpiece, preventing material deformation. Furthermore, there is no tool wear, ensuring consistent cut quality over long production runs and eliminating downtime for tool changes.
High Flexibility: The process is controlled by software, so changing from one part design to another is as simple as loading a new CAD file. This makes laser cutting ideal for rapid prototyping, small batch production, and high-mix manufacturing environments.
Material Versatility: A single laser system can often be configured to cut a wide variety of materials of different thicknesses, from thin foils to thick plates, simply by adjusting process parameters.
Yes, you can absolutely cut with a galvo laser system, and in many applications it is the preferred method. A galvo laser, which uses high-speed scanning mirrors to steer the beam, excels at cutting intricate, high-detail patterns within its field of view at extremely high speeds.
Instead of moving a large gantry, the lightweight mirrors of the galvo scan head can trace complex vector paths almost instantaneously. This makes galvo laser cutting ideal for:
Flexible Circuits: Cutting the complex outlines of flexible PCBs with high speed and precision.
Medical Stents: Tracing the intricate filigree patterns of stents from thin-walled tubing.
Scribing: Creating fine scribe lines on silicon or glass wafers for subsequent "dicing" or separation of chips.
Textile and Fabric Patterning: Rapidly cutting complex patterns in cloth or leather.
For cutting parts larger than the galvo's field of view, Aerotech's Infinite Field of View (IFOV) technology seamlessly synchronizes the motion of the galvo scanner with servo-driven stages. This hybrid approach combines the long-range travel of the stages with the high-speed agility of the galvo, allowing large parts to be cut quickly and without any stitching errors between adjacent scan fields.
While distinct from cutting a continuous path, the laser drilling process is a closely related material removal technique that uses a focused laser beam to create holes. In many ways, drilling a hole can be thought of as a very short, targeted cutting operation. The fundamental physics are the same: the laser energy is absorbed by the material, causing rapid heating, melting and vaporization. The resulting material is then ejected, leaving a hole.
Laser drilling is often performed using several techniques:
Percussion Drilling: A single pulse or a burst of pulses is fired at a fixed point to create the hole. This is extremely fast.
Trepanning: The laser beam is steered in a circular path to "cut out" the hole. This method, often performed with a galvo scanner, provides excellent control over the hole's diameter and quality.
Helical Trepanning: For the highest precision, the beam is moved in a spiral path to machine the hole to depth. This is a common technique in demanding aerospace and medical applications.
The type of laser beam used for drilling depends heavily on the material being processed and the required hole size and quality. Just as with laser cutting, the goal is to choose a laser whose wavelength is well-absorbed by the material and whose beam characteristics can be tailored to the application.
Common choices include:
Pulsed Solid-State Lasers (Nd:YAG, Fiber): The high peak power of pulsed lasers is very effective at vaporizing material for clean drilling with minimal thermal input. Their ~1 µm wavelength is well-suited for drilling metals.
Ultraviolet (UV) Lasers (Excimer, Frequency-Multiplied Solid-State): UV lasers are used for "cold" ablation drilling, where photochemical processes break material bonds with very little heating. This is ideal for drilling polymers and other heat-sensitive materials, such as creating microvias in electronic substrates.
Ultrafast Lasers (Picosecond, Femtosecond): These lasers deliver extremely short, high-energy pulses that can ablate nearly any material with unparalleled precision and virtually no heat-affected zone. They are the go-to solution for drilling in brittle materials like glass and ceramics and for creating the highest quality micro-scale holes.
The beam mode (e.g., TEM₀₀) is also critical, as a high-quality beam with a low M² value can be focused to a smaller, more intense spot, enabling the drilling of finer holes with higher precision.