Laser cutting stands at the center of manufacturing industries. It uses a high-energy-focused laser beam to mark and engrave functional parts. Lasers make intricate designs, texts, and graphics on auto parts, medical devices, and woodwork. These markings allow for customization and easy traceability of parts.
There are three types of lasers; Nd: YAG lasers, fiber, and CO2. Though they operate in similar ways, they are different and have unique applications. Before using any type, it is important to understand how each works. This article will explain laser cutting, types of laser cutters, laser marking advantages, disadvantages, and applications.
What is Laser Cutting?
Laser cutting is a noncontact process that uses precise and controllable heat to cut a material. The heat source is a highly focused laser beam that either vaporizes, melts, burns, or blows a surface to achieve the smoothest finish possible. Laser machining has 3 primary types; remote, flame, and fusion cutting
Remote Cutting: Remote cutting is the partial ablation of metals without the use of cutting gas. The energy input is less which makes this process useful when working with thin and sensitive sheets.
Flame Cutting: This is a reactive process that uses oxygen with natural or acetylene gas to cause ignition and melt the surface of steel. Flame cutting is a slow process with a large heat-affected zone.
Fusion Cutting: In this process, argon or nitrogen serves as the cutting gas that blows the molten metal off the surface. The use of these inert gasses prevents reaction with atmospheric oxygen leaving a surface that may not require further treatment.
Laser Cutting Process: How do Laser Cutters Work
A fiber laser cutter works by generating the g code and laser beam before marking or etching. Below is a detailed explanation of the steps of laser cutting
Generation of G Code
Before carrying out the laser cutting process, the first step is to generate the g code. This code is the language the machine understands.
It gives instructions about how and where the cutting head should move and represents the pattern that has to be cut into the material. G code is written using the CAM software and transferred using a cable or over an internet connection.
Generation and Amplification of Laser Beam
Next is the generation of laser beams. This process occurs inside the laser cutter using a gain medium, optical elements, and two reflecting mirrors. Note that the two mirrors are not alike; one is reflecting while the other partially reflects light. When energy is supplied to the gain medium, the electron present gets excited to a higher energy level. As it relaxes to its metastable state, it releases a photon.
This photon interacts with another electron to release another photon of the same wavelength. This cascade reaction leads to the amplification of light. When the gain medium is in between the two reflecting mirrors. The amplified photons pass through the slightly transparent mirror to form a laser beam.
Cutting Process
The cutting process involves directing the laser beam on the area you want to cut. This process uses a lens that focuses the beam of light into a small diameter. As the laser beam comes in contact with the surface of the material, it melts and cuts through it. Simultaneously, an inert gas such as argon or nitrogen blows the molten material away to leave a fine cut.
Note: Before shaping of metals, ensure you set the laser parameters including the laser power, focal length, and speed.
Cooling and Finishing
Many laser cuts have an inbuilt cooling system that prevents overheating. Once you have the final product, you can use additional post-processing techniques to improve the surface finish.
Metal Laser Cutting: Three Main Types of Lasers
There are three main types of laser cutters used for cutting, etching, and engraving. Their gain mediums and pumping mechanisms differentiate them. This section will explain the types and how they function
CO2 Lasers
This type uses carbon dioxide along with helium, hydrogen, and nitrogen as the gain medium. These additional gasses serve specific functions and enhance the overall performance of the laser cutting system. CO2 lasers have high power and produce infrared light with a wavelength of 10.6 micrometers
While one can process certain metals using CO2 lasers, non-metallic materials are typically the best candidates for them. Materials such as wood, paper, leather, fabrics, and plastics absorb light perfectly at this wavelength. This laser type is not ideal for materials that are highly reactive or those that have high thermal absorption.
Fiber Lasers
The gain medium here is a fiber doped with rare earth elements such as ytterbium, neodymium, and erbium. When energy is applied, the dopant ions absorb it and emit photons. The wavelength of the laser beam varies and depends on the dopant one is using. Generally, the shorter the wavelength, the higher the absorption rate.
Fiber lasers are ideal for reflective materials such as copper, bronze, gold, and silver. They are energy efficient, produce narrower beams, and use less power than other types.
Nd; YAG/Nd: YVO Lasers
Neodymium-doped yttrium aluminum garnet is the gain medium in this solid-state laser. The application of external energy causes excitation of the neodymium ions that emit the laser beam at a wavelength of approximately 1.064 micrometers.
YAG lasers have superior efficiency and a small heat-affected zone. The movable components are fewer and require minimal maintenance. Additionally, they cut many materials including metals, plastics, and ceramic with high levels of accuracy and precision.
| Parameters | CO2 | Nd: YAG lasers | Fiber |
| Working Principle | Gas laser | Solid-state laser | Solid-state laser |
| Wavelength | 10.6 µm (infrared) | 1064 nm (mostly) | Typically around 1064 nm |
| Material | Metals, ceramics, plastics, wood, acrylic, etc. | Metals, ceramics, plastics, semiconductors, etc. | Metals, plastics, ceramics, composites, etc. |
| Cost | Moderate to high | Moderate to high | Moderate to high |
| Cooling | Water or gas | Water | Air or water |
| Efficiency | Moderate | Moderate | High |
| Beam Quality | Good | Good | Excellent |
| Output Power | High | Moderate to high | High |
| Maintenance | Moderate | Moderate | Low |
| Application | Cutting, engraving, marking, welding | Welding, cutting, engraving, marking | Cutting, welding, engraving, marking |
Table showing a detailed omparison between CO2, YAG, and fiber lasers
Common Laser Cutting Materials
One of the most significant benefits of laser cutting is its ability to cut almost any material. These include metals, plastics, wood, and leather.
- Metals
Common types of metals for laser machining are carbon steel, stainless steel, titanium, copper, aluminum, and brass.
Carbon Steel
There are different categories of carbon steel. They have varying amounts of carbon content ranging from 0.12% to 2%. The higher the carbon content, the lower the melting point and the easier it is to laser cut. The most commonly used type of laser for carbon steel is the fiber type. The focal length and speed you use will depend on the thickness of the carbon steel material.
Stainless Steel
It is possible to work on all grades of stainless steel using different laser parameters. You can mark, etch, or engrave it using either fiber or CO2 lasers. The stainless steel marking operation can either be annealing or ablation.
These techniques make clean markings that may not need further processing. However, laser engraving can cause mild discoloration. Stainless steel finds widespread application in outdoor uses that demand superior finishes.
Titanium
Titanium is strong with a high melting point. Though challenging, it is possible to cut with the right settings. For best results, use a CO2 laser in conjunction with either oxygen or nitrogen. Laser-cut titanium has a widespread application because of its exceptional strength and lightweight nature.
Copper
Copper has a good thermal and electrical conductivity making it a suitable candidate for laser cutting. Fiber laser is the ideal type as it reduces copper discoloration issues. However, it is still possible to use CO2 lasers. When using CO2 lasers for copper material, it is important to spray the workpiece with metals that can exceed its energy before cutting.
Aluminum
Laser cutting aluminum is a popular process in manufacturing industries. This is because aluminum is highly reflective making it easy to cut more quickly. Virtually any laser can be used. However, the most suitable are CO2 and fibers. The method one uses depends on the thickness of the workpiece and the desired result.
Brass
Brass is an alloy of zinc and copper. Copper is soft making brass easier to cut using lasers. CO2 and fibers are the most common for laser brass cutting. However, fiber lasers are preferred because they melt brass easily at a shorter wavelength. Brass is highly reflective and absorbs very little laser energy. To cut brass well, use a slow speed and melt as quickly as possible.
- Plastics
Plastics are another category of materials one can laser cut. The most suitable is CO2 lasers as most plastics absorb energy at that wavelength. Fiber lasers also work. However, it is mainly used for engraving. The most common plastics for laser cutting are acrylic, styrene, lucite, and polyoxymethylene.
- Wood
Lasers can mark, cut, and engrave wood seamlessly. CO2, fiber, and diode lasers work perfectly with both hard and soft woods. Diode lasers are preferable for pictures or artworks because of the diverse color options it has. CO2 lasers are more powerful and do not produce waste.
- Leather
Lasers can also cut through both thick and thin leather parts. For thick materials like journals and shoes, using two passes make finer engravings. Note that the type of laser used and the result depends on the leather type. Additionally, you can not laser cut all types of leather. Some are flammable and produce toxic fumes.
Advantages of Laser Cutting System
There are several benefits of using a fiber laser cutter for metal technology. The following are some advantages
- Accuracy and Precision
Laser cutting comes with high accuracy and precision. It is automated and can create repeatable complex designs even on challenging or delicate materials. It comes with high tolerances up to +/- 0.1mm. It is important to use the right settings and properly align the mirrors to improve laser cutting accuracy.
- High Speed
Metal laser cutting is a noncontact process which makes it very fast. The laser cutting speed depends on the type and thickness of the material, laser power, and width of the cut. It is slower to cut through thick materials that have high thermal conductivity.
- Versatility
Laser machining is a versatile process. Different types are available to meet the diverse needs of various industries. Additionally, it is compatible with many engineering-grade materials. This further intensifies its widespread use in manufacturing industries.
- Environmentally friendly
Metal laser cutting does not use harmful chemicals to mark a part. It is eco-friendly if you manage it properly. Furthermore, it is possible to collect the dust and smoke given off during the cutting process. As a result, the operator and other employees are safe and free from hazards.
- Low Maintenance Cost
The cost of maintaining a laser cutting system is relatively low. Maintenance involves cleaning the beds, removing debris from the machine base, and occasionally tightening loose bolts and nuts. The machine does not break down easily in between operations.
Disadvantages of Laser Cutting System
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
The cost of buying and installing a laser cutting machine is high. The cost is nearly twice as expensive as a plasma cutter. These prices vary based on the type of laser cutter you want to use. However, the ROI of the machine is high. One will make more than the initial investment in a short time.
- Limitations to Metal Thickness
Metal laser cutting comes with a thickness limit. Based on the type you are using, there are different levels of thickness they work with. The average thickness is usually 15-20mm. Going above this will require the service of a very skilled operator.
- Requires Technical Knowhow
Operating an industrial laser cutting system requires a range of technical skills. The machinist must be able to operate the machine, under programming, and interpret results. Obtaining these skill sets may be expensive and further adds to the overall cost of the laser cutting system.
Laser Cutting Machine Applications
From medical implants to customized jewelry, many manufacturing industries benefit greatly from lasers. They use laser cutters in different ways to improve a part’s function and appearance.
- Automotive Marking
Auto part manufacturers use laser marking extensively. This technique is important in all stages of car manufacturing. The most common type used is CO2 lasers and fiber lasers. They are ideal for both low-volume and mass production of engine components, body panels, and exhaust systems. Additionally, they create customized car components to aid in easy tracking.
- Ceramic Manufacturing
Ceramics are hard and employing conventional marking techniques may be energy intensive. Hence, the use of lasers to fabricate and manufacture ceramic components. This process is commonly used for traditional, advanced, and engineering ceramics. It creates decorative features and logos on porcelain and stoneware.
- Packaging Items
Laser cutting is used to mark and engrave packaging components such as lids, boxes, and containers. Both fiber and CO2 lasers are suitable options. The one you use depends on your budget and other factors. Many industries use wood in the form of cardboard for packaging. Cardboard is a good candidate for laser cutting and one can easily customize it.
- Jewelry Industry
Metal laser cutting has a widespread application in the manufacturing of jewelry. It can be used to cut precious stones as the process does not waste materials. Rather than ‘cutting’, it evaporates to leave unique engravings and texts. It is better than the traditional technique as it can create more complex designs on earrings, rings, and bracelets.
- Medical Device Marking
Laser marking has revolutionized the medical industry. It produces superior and sterile cuts that are compatible with body fluids and tissues. This technique has been used in the manufacturing of heart valves, stents, and other devices that must fit accurately for functionality. The small heat-affected zone leads to minimal distortion and parts that meet strict tolerances.
Conclusion
What is laser cutting? What is laser cutting used for? We hope we have answered all your questions. This article provides a detailed explanation of the laser cutting process, how to laser cut. and the advantages and disadvantages of using it.
To get the best of laser cutting, it is good to use the services of a contract manufacturer. Zintilon has been in the laser marking sector for many years providing safe and innovative solutions. Our systems are automated and provide permanent marks in a single operation. What more? Our prices are affordable and competitive. Reach out to work with our skilled machinists to bring your ideas to life.
FAQ
What materials are not compatible with laser cutting?
Despite being able to mark and engrave many materials, there are some that one must not use with a laser cutter. Lasers cannot cut glass, carbon fiber, fiberglass, and those containing halogens. Some of these materials are flammable, some melt while others produce toxic fumes.
What are the alternatives to laser cutting?
Some laser cutting alternatives are plasma cutting, laser drilling, engraving, and water jet cutting.
What are the forms of laser cutting?
The common forms of laser cutting are fusion cutting, flame cutting, remote cutting, thermal stress fracture, stealth dicing, and laser rastering.
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