Surface microstructural changes in materials cannot occur unless they are cut. Laser cutting is a common method for cutting materials for machining. It aids in the creation of shape based on designs and desired outcomes. In this process, materials are melted, burned, and vaporized by a powerful laser beam. While this method is very effective, it is critical to understand the various laser-cutting benefits and drawbacks.
The cutting process is successful thanks to a laser cutter, which focuses a thin laser beam on the material. However, before cutting, you must have a specific target based on your designs or patterns. Some hard materials are complex for manufacturers to cut through. However, it is now possible thanks to the introducing of a laser cutter.
Here, we’ll walk you through everything you need about laser cutting. We will also explain how it works and the benefits and drawbacks of laser cutting.
Metal Laser Cutting: A Brief History
The Western Electric Engineering Research Centre began using laser cutting technology for diamond die drilling in 1965. Soon after, scientists developed the carbon dioxide laser cutting method. This advancement increased laser cutting’s versatility. Developing lasers capable of cutting through metals such as mild steel was critical to the technology’s mass adoption.
Boeing was the first company to use gas laser cutting commercially in 1969. This company’s employees wrote a paper discussing using a carbon dioxide laser to cut titanium, Hastelloy, and ceramic. This paper resulted in the development of multi-beam laser cutting, and Boeing began using laser beams on its production lines as an efficient cutting method.
Western Electric started manufacturing cutting machines in large quantities for the aerospace industry in the 1970s. The use of gas laser cutting spread throughout the 1980s. An estimated 20,000 industrial laser cutters were in use during this time. The advent of laser cutting technology signaled the beginning of a new industrial revolution and altered the manufacturing sector.
The possibilities for laser cutting technology were greatly expanded when Prima Industrie of Collegno, Italy, invented a 3D laser cutting method in 1979. Nowadays, laser power is widely used in many industries, most notably the auto industry.
How Does Laser Cutting Work?
It’s essential to understand how laser cutting operates before delving into its benefits and drawbacks. Although they use a high-power laser, laser cutting machines work similarly to CNC machines. Through the use of optics and CNC, the laser will direct itself to guide the material or beam. The tool will cut into the material and regulate the motion using the supplied CNC or G-code.
The material will melt, evaporate, and burn after the laser beam is focused. Also, blowing the material with a gas jet can yield a high-quality finished edge surface. In a closed container, lasing materials are stimulated by lamps or electrical discharge to produce a laser beam.
After reflecting internally through a partial mirror, the lasing materials are amplified. Until sufficient energy is accumulated in the form of a coherent monochromatic light stream to permit its escape, the phenomenon persists. After focusing on the work area using mirrors or fiber optics, the light’s intensity rises.
A laser beam’s thinnest edge has a diameter of less than 0.32 mm. On the other hand, the kerf width could be as small as 0.10 mm. But the material’s thickness determines this. Use the piercing method if the laser cutting machine cannot start cutting the material from its edge. The high-power laser can create a hole in the material through the piercing process. For example, it will take five to fifteen seconds to burn through a sheet of 13 mm stainless steel.
What Are the Types of Lasers for Cutting
These are the common types of lasers available for cutting:
Direct Diode Lasers
Direct diode, also known as simply diode, lasers are a laser technology that produces laser light using single semiconductor junctions. They are becoming more popular in industrial applications such as surface treatment, welding, and cutting. Semiconductor junctions, usually composed of gallium arsenide (GaAs), are the foundation of a direct diode laser. Without an initiation light source, the diode emits light through electroluminescence when a forward bias current is supplied.
The laser energy is then emitted through a stimulated emission resonant cavity, formed by optical elements with a half mirror at one end, guiding and focusing the emitted light into a laser beam. The choice of semiconductor material, dopants, and resonant cavity design allows diode lasers to be produced in a wide range of wavelengths. Direct diode lasers are most frequently used in cutting applications at wavelengths in the near-infrared range, roughly 900 to 1,100 nm (0.9 to 1.1 μm). Systems using alternative diodes can emit in the green and blue wavelength ranges.
Although direct diode laser beam quality can vary greatly, overall diode beam quality is getting better with each new device generation. Frequently, beam quality could be better than that of CO2 or fiber lasers.
Nd:YAG/Nd:YVO Lasers
While nd:YAG (neodymium-doped yttrium aluminum garnet) crystals can be used in crystal laser cutting processes, nd:YVO (neodymium-doped yttrium ortho-vanadate or YVO4) crystals are typically used instead. The cutting power that these devices allow is incredibly high. These devices have the disadvantage of being somewhat pricey, not only because of their purchase price but also because of their 8,000–15,000 hour life expectancy (the latter being usually lower for Nd:YVO4) and the relatively high cost of the pump diodes.
With a wavelength of 1.064 micrometers, these lasers have many uses, including manufacturing, dentistry, medicine, and the military. In contrast, Nd:YVO has a shorter upper-state lifetime, a higher refractive index, lower thermal conductivity, a wider bandwidth, a wider wavelength range for pumping, and higher pump absorption and gain. Regarding continuous operation, Nd:YVO and Nd:YAG in medium- or high-power cases perform similarly overall. Nd:YVO has a shorter laser life than Nd:YAG, and it does not permit as high of pulse energies.
Fiber Lasers
This class of devices uses the seed laser and is a member of the solid-state laser group. With specially made glass fibers that get their energy from pump diodes, they amplify the beam. Their focal diameter is minimal due to their general wavelength of 1.064 micrometers. Additionally, they are usually the priciest of all the laser-cutting equipment available.
Fibre lasers have a long service life of at least 25,000 laser hours and typically require no maintenance. As a result, fiber lasers can produce solid and stable beams and have a far longer lifespan than the other two types. With the same average power, they can achieve intensities that are 100 times higher than those of CO2 lasers.
Fibre lasers have various functions, including quasi-continuous beams, continuous beams, and pulsed settings. The MOPA is one type of fiber laser system where pulse durations can be adjusted. Because of this, the MOPA laser is among the most adaptable and multipurpose lasers. Fibre lasers best mark metal through metal engraving, annealing, and thermoplastic marking. Glass, wood, and plastic are among the non-metals it can work with in addition to metals and alloys.
CO2 Lasers
A CO2 laser produces light beams by passing electricity through a tube filled with gas mixtures. There are mirrors on both ends of the tubes. One of the mirrors reflects light completely, while the other only partially does so. Typically, the gas mixture consists of helium, hydrogen, nitrogen, and carbon dioxide. CO2 lasers produce invisible light in the far infrared spectrum.
The exception is the industrial machines that have CO2 lasers with multiple kilowatts of power, which is the highest power available. CO2 lasers for machining typically have a power output of 25 to 100 Watts and a wavelength of 10.6 micrometers.
Working with wood, paper, and their derivatives, polymethyl methacrylate, and other acrylic plastics are the most common applications for this kind of laser. Working with leather, fabric, wallpaper, and related products is another helpful application. Moreover, it has been used in the processing of cheese, chestnuts, and a variety of plants.
Pros of Laser Cutting
There are several advantages of laser cutting technology. Here are some of te advanatages:
High Precision
The high cutting quality is ensured by the energy beam’s narrowness and the material’s or the laser optics’ ability to be moved precisely. Even on challenging or delicate material substrates, laser cutting enables the execution of complex designs that can be cut at high feed rates.
Several Applications and Industries
Laser cutting is used in various manufacturing applications because of its precision, speed, and versatility. The majority of manufacturing industries rely heavily on sheet materials for production. Different sectors have utilized laser cutting for multiple purposes, such as mass production, medical implants, ships, electronics, airframes, and rapid prototyping.
Increased Speed
Few production methods can come close in processing speed to laser cutting. Cutting a 40 mm steel sheet using a 12 kW oxygen-assisted laser provides speeds some 10x faster than a bandsaw and 50–100 times faster than wire cutting.
Absence of Material Contamination
Coolants must be used when processing materials with rotary cutters traditionally. The parts that have been cut may become contaminated by the coolant and need to be cleaned. Applying coolant or lubricant may also be necessary during grinding operations. Natural process ablation of the grinding wheel leaves carbide granules in many products, which can be dangerous. In a similar vein, water cutting leaves residue of garnet. There is no chance that the materials used in laser cutting will contaminate the produced parts—only energy and gases are used.
Range of Materials
Various materials, including acrylic and other polymers, mild steel, titanium, hastelloy, and tungsten, can be efficiently cut using versatile laser cutting technology. With the advancement of technology, this adaptability grows. To cut carbon fiber-reinforced composites, for instance, dual-frequency lasers can be used—one frequency for the fiber and another for the bonding agent.
Infinite 2D Complexity
Due to the small size of the applied energy hot spot and the positioning method of G-code movement control, laser cutting allows for intricacy. The process is, therefore, essentially limited by material properties rather than process capabilities since features that are only loosely attached to the main body are cut without force.
Cons of Laser Cutting
Despite the several benefits of laser cutting, it also has a few downsides you should know. We will discuss some of them below:
Upfront Costs
You might have to pay a lot to purchase a CNC laser cutting machine. For instance, laser cutting is nearly twice as expensive as plasma cutting when compared side by side. Although buying the machine will cost a significant amount of money, you will ultimately make more than that.
Limitations to Metal Thickness
Thick metals are best cut using a different method, even though laser cutting works with nearly any material, including sheets. The thickest sheets can be found using the available machine, though using it also needs an experienced operator. The average range used by most manufacturing companies is 15 to 20 mm.
Requires Technical Knowhow
It takes a skilled operator to use every feature on the machine and spot issues promptly. Inaccurate apparatus setup will impact the materials and lead to more substantial harm to the laser cutting. Employing an operating specialist is crucial, but it costs a lot of money because there are only so many skilled workers in the field. You can hold online meetings using video interviewing software to reduce commute time; it’s more convenient and adaptable.
Evaporation of Some Materials
Evaporation frequently happens when cutting certain materials, like plastics. One major drawback of laser cutting is this. Expert machine operators can easily overcome this drawback, even though it is manageable. To avoid this issue, the experts rearrange some of the device’s configurations. But these days, it comes at a very high cost actually to implement these changes.
Production of Harmful Fumes and Gases
Many materials can be used with laser cutting. There is a drawback to laser cutting’s near-universal compatibility with materials. As a material melts during thermal cutting, toxic fumes and gases are released. When working with plastic materials, the production of these harmful gases is usually expected.
What Are the Materials That Can Be Laser Cut?
One of the most significant benefits of laser cutting is its ability to cut almost any material, including thin to thick metals, wood, and plastic. Common metals that can be cut are mild steel / low carbon steel, stainless steel, titanium, tool steel, copper, aluminum, and brass.
Mild Steel/ Low Carbon Steel
Currently, mild steel, or low-carbon steel, is the most widely used type, with a carbon content of 0.05–0.25%. In general, fabrication, when high strength is not needed, is the go-to option for laser cutting structural shapes and brackets. With its low tensile strength and good machinability, weldability, and flexibility, mild steel is an affordable material. Mild steel makes laser cutting more difficult despite being inexpensive and simple to form.
Stainless Steel
This is one of the most widely used materials for laser cutting, mainly Austenitic grades 304 and 316. Because stainless steel has a high chromium content, it is incredibly corrosion-resistant, strong, weatherproof, and appropriate for outdoor use. Furthermore, compared to mild carbon steel, the steel is easier to cut due to its nickel content. It can produce cutouts with tiny radii and extremely smooth edges. Stainless steel finds widespread application in sectors that demand superior finishes.
Titanium
Laser cutting can create precise and intricate cuts, even though titanium is difficult to cut. Titanium finds widespread application in the aerospace, medical, marine, and automotive industries owing to its exceptional strength and lightweight nature.
Tool Steel
Laser cutting is possible for air-hardening grades such as D2 and A2, but high-power density CO2 lasers are needed due to their extreme hardness. Punches, dies, and other instruments can be cut with tool steel. To avoid cracking, cutting parameters must be closely regulated.
Copper
Copper is used in plumbing and electrical applications because of its exceptional electrical conductivity. It can be successfully cut with a laser, but because of its heat conductivity, stronger lasers might be needed. Generally speaking, fiber lasers can be used to reduce copper discoloration issues. This metal is frequently used in heat exchangers and electrical contacts when laser cutting is used.
Aluminum
Because it is a lightweight metal, laser cutting can be done effectively with aluminum. It is common practice to laser cut certain non-heat treatable grades, like 5052 and 6061. Although it can be cut more quickly due to its high reflectivity, the edges can easily oxidize. Automobiles, consumer electronics, aerospace, and electronic enclosures all use this metal.
Aluminium will inevitably get scratches from laser cutting, just like any other metal. A solution would be to avoid hard friction and sharp edges on the material surface. Additionally, the surface can be preserved by applying a light oil or clear lacquer. Even though the sheets frequently have scratches on the back, these can easily be fixed with a mild abrasive.
Brass
Because brass is a zinc-copper alloy, more zinc contributes to its strength and flexibility. It can be successfully laser-cut. Coins, electronic packaging, hose couplings, ammunition casings, automotive radiators, locks, hinges, gears, bearings, and costume jewelry are a few common applications for brass.
Conclusion
This guide has explained the pros and cons of laser cutting, their benefits, and why they should be considered. Contact Zintilon CNC laser cutting services to learn more about laser cutting.
Zintilon provides a wide range of manufacturing services, including sheet cutting and other value-added services, to meet all of your prototyping and production requirements. Request a free quote today!
