Sheet Metal Laser Cutting: Fundamentals

Subtractive manufacturing techniques are commonly used for part fabrication in various industries, with sheet metal laser cutting being a key method. This precise and accurate process focuses a laser beam on the material surface to burn, vaporize, or melt it, producing the desired outcomes. This guide provides all the essential information you need before incorporating laser cutting into your next manufacturing project.

What’s Sheet Metal Laser Cutting?

Sheet metal laser cutting is one of the primary industrial manufacturing techniques. As such, sheet metal laser cutting appears to be one of the go-to procedures. Laser cutting fabrication uses a high-power beam of light (laser) to cut out flat and thin sheets of metals. The process is directed by optics and computer numerical control (CNC) technology, which accounts for the high precision of laser cut parts. 

History of Sheet Metal Laser Cutting

Laser cutting technology has been in existence for over 60 years, with its first attempt to cut metal sheets dating as far back as 1960.

By 1964, CO₂ lasers were already in use for manufacturing intricate details such as welding clock springs. The automation and high precision features of laser cutting over other cutting processes made them widely accepted for delicate manufacturing and large volume production.

Fiber lasers were first produced in the 60s, but not until the late 80s before they hit the commercial market. The 1990s is regarded as the golden age of laser tech – as it gave way to many high-power lasers, like the solid-state lasers that vastly improved efficiency and productivity. By the early 2000s, laser cutting services were now a widely accepted manufacturing technique used by several industries, such as the automotive and aerospace industries.

Types of Lasers For Sheet Metal Cutting

There are three different forms of lasers for cutting materials in industrial manufacturing. Each laser cutter has unique features that distinguish them from another. With that said, below is a comprehensive summary of the three types of laser cutters.

Fiber Lasers

Fiber laser cutting machines are some of the most potent precision cutting devices. They belong to the solid-state lasers using seed lasers to amplify the beam with special glass fibers. They are effective for cutting pieces of metals, alloys, and non-metals like glass, plastics, and even wood. Other than simple cutting operations, they are suitable for metal engraving and annealing.

Fiber laser kerfs are more extensive than others; this may account for their high power. They possess a long service life of not less than 25,000 hours and thus require less maintenance. They produce some of the strongest and most stable beams. However, they are best suited for materials with less than 20 mm thickness.

CO₂  Lasers

CO₂ lasers produce the beam of light by running electricity through a tube filled with a mixture of gases. The gas mixture contains mainly carbon dioxide and inert gases – helium and nitrogen, the commonest forms for lasers.

However, they are less potent compared to fiber lasers. CO2 laser machines can only cut non-metals like wood, acrylic, and plastics. In some cases, they may also function for sheet metal laser cutting, especially thin sheets of aluminum and some other non-ferrous metals.

Crystal Lasers

Crystal laser cutters exist in two forms: Nd:YAG (neodymium-doped yttrium aluminum garnet) and Me:YVO (neodymium-doped yttrium ortho-vanadate, YVO4) crystals. Both are incredibly high-power cutting devices. However, they are pretty expensive yet have about half the life expectancy of fiber lasers – 8,000 to 15,000 hours. They are suitable for cutting coated and uncoated metals, non-metals and plastics, and even ceramics under specific circumstances.

Three Sheet Metal Laser Cutting Processes

Laser cutting sheet metal is the thermal process that involves using a laser beam to cut out pieces off a metal sheet. Primarily, there are three methods of cutting sheet metal.

Laser Beam Fusion Cutting

Fusion cutting uses an inert cutting gas, often nitrogen or argon, to thrust out the molten material from the cutting torch. Since using the inert gas, it prevents oxidation at the cutting edge without reacting with the process. The process is suitable for flat and thin sheets and for cases where material must meet high visual requirements and fewer post-processing needs.

Laser Beam Flame Cutting

Flame cutting uses oxygen gas to expel the molten material. It causes an exothermic reaction which accounts for an increase in the overall energy input of the process. The process is ideal for cutting mild steel, among other types of sheet metals and fusible materials like ceramics.

Laser Beam Sublimation Cutting

Sublimation cutting uses a laser to evaporate parts of a material with less melting. Like fusion cutting, inert gases – nitrogen, helium, or argon serve as cutting gas, which ensures that the cutting edges are free of oxidants. Though it’s slow, it produces top-quality edges for high-precision cutting.

Advantages of Sheet Metal Laser Cutting

Below are five critical advantages of this manufacturing technique.

High Precision Cuts

The light beam cuts metals with very high precision in laser cutting fabrication. The accuracy and precision at which the laser melts and evaporates materials are incomparable to many other cutting methods. Some die cutting tools have tolerance levels of about 1 to 3 mm, while laser cutters cut at accuracy as low as 0.003mm.

High Sheet Utilization

Laser cutters provide the opportunity to use a large percentage of the fabricating materials. The technology gives little or no room for wastage – the machine maximizes the number of usable parts of any metal sheet. Therefore, less worry about providing excess materials; you can buy the exact amount knowing that it’d be enough.

Extreme Cutting Versatility

Laser cutting operations are highly flexible and versatile. A single laser cutter functions well for different cutting operations, such as simple cuts, complex ones with intricate details, markings, drilling even engravings. Therefore, manufacturers do not need to replace tooling from time to time during the process.

Low Power Utilization

Laser cutters do not require moving different parts of the device, unlike some other cutting machines. This allows them to effectively cut out pieces of material without consuming too much energy. While laser cutters can function with 10kW of energy, most other procedures can use up to five times.

Little or No Damage

Perhaps you think the exposure of heat to materials in laser cutting may cause warping or distortion of parts or even total damage. Well, this is untrue. The parts affected by heat in laser cutting are minimal and pose no threat to the tolerance of the features or components after fabrication.

Disadvantages of Sheet Metal Laser Cutting

Despite its numerous benefits, laser cutting sheet metal has a few shortcomings. Let’s discuss them.

Need for Specialist Operator

To best utilize your laser cutters, you might need to employ a professional to operate the machine for part’s fabrication. An expert, for example, will quickly detect a fault or an improper setup that may affect the production processes or even the machine’s integrity.

Limitations on Metal Thickness

Although laser cutting can work well with an extensive array of materials, including metal sheets, it is advised to use other cutting procedures when dealing with thick metals. Typical laser cutters are great for cutting aluminum sheets with a maximum thickness of 15 mm and steel of 6 mm.

Harmful Gases

As laser cutters melt and evaporate materials, they release harmful fumes significantly when cutting plastic. Consequently, it is vital to operate laser cutting in a well-ventilated room or safe working environment.

High Initial Investment

The cost of a top-quality laser cutter is high. A typical laser cutter may cost about $3000, which is twice as high as the cost of waterjet or plasma cutters. To engage in laser cutting services as a business means, you need to bear the high initial investment.

Power Tools for Metal Cutting

When efficiency and power are needed, electric and pneumatic tools come into play. These tools can handle larger projects and tougher materials with ease.

Angle Grinders

Angle grinders are versatile tools that can cut, grind, and polish various metals. With the right attachment, they’re capable of cutting through rebar, fencing, and even steel plates.

Angle grinders are available in various sizes, including portable cordless models ideal for outdoor projects.

When using an angle grinder for cutting, always use a metal cutoff wheel and let the tool’s weight do most of the work. Avoid applying extra pressure, which can cause the wheel to bind or break.

Circular Saws

While circular saws are traditionally used for woodworking, they can also be used for metal-cutting tasks with the right blade. They’re particularly useful for cutting sheet metal, roofing, and corrugated metal. Here’s how to use a circular saw for metal cutting:

1. Install a metal-cutting blade with the appropriate tooth count for your material.
2. Mark your cutting line clearly.
3. Secure the metal to prevent vibration and ensure a straight cut.
4. Cut slowly and steadily, allowing the blade to do the work without forcing it.

Circular saws are excellent for making long, straight cuts in metal roofing or siding. They can also handle stacked sheets, saving time on repetitive cuts.

Reciprocating Saws

Reciprocating saws, often called sawzalls, are the Swiss Army knives of power tools. They can cut through various materials, including metal pipes, sheets, and profiles. Different blades are available for various metal types and thicknesses, and these saws have enough power to handle thick metal stock that might be challenging for other handheld tools.

When using a reciprocating saw, make sure the material is firmly clamped and use a blade appropriate for the metal’s thickness. Let the saw do the work, applying only moderate pressure to guide it through the cut.

Specialized Metal Cutting Equipment

For professional-grade cutting or specialized applications, more advanced tools are often necessary. These tools offer precision, power, and efficiency for larger or more complex metal-cutting tasks.

Plasma Cutters: High-Tech Precision

Plasma cutters use a high-temperature plasma arc to slice through conductive metals with precision. They’re ideal for cutting sheet metal, plate steel, and other conductive materials. Benefits of plasma cutters include the following:

• Speed: Can cut through thick metal much faster than traditional methods
• Precision: Capable of making intricate cuts with minimal material waste
• Versatility: Can cut a wide range of metal thicknesses and types

While plasma cutters are expensive, they’re a great addition to metalworking shops and for fabricators who frequently work with thick or complex metal pieces.

Oxy-Acetylene Torches: Heavy-Duty Cutting

Oxy-acetylene torches are powerful tools that use a mixture of oxygen and acetylene gas to create a high-temperature flame capable of cutting through thick metal. They’re particularly useful for the following:

• Cutting thick steel plates and structural steel
• Demolition work where precision isn’t critical
• Situations where electrical power isn’t available

Using an oxy-acetylene torch requires skill and practice. If you use this tool, wear appropriate protective gear and have proper ventilation.

Cold Saws: Clean Cuts for Professionals

Cold saws are precision cutting tools that use a circular blade and coolant to make clean, accurate cuts in metal without generating excessive heat. They offer several advantages, including the following:

• Precision: Produce clean cuts with minimal burring
• Efficiency: The coolant system allows for continuous operation without overheating
• Longevity: Blades last longer due to reduced heat and friction

While more expensive than some other options, cold saws are invaluable for metalworking professionals who regularly complete high-precision cuts.

Choosing the Right Tool for Your Project

When choosing a metal cutting tool, consider these factors:

1. Metal type and thickness: Softer metals, like aluminum, require different tools than hardened steel.
2. Cut precision: Some projects require clean, precise cuts, while others allow rougher edges.
3. Project scale: Large-scale projects may justify investing in more powerful, efficient tools.
4. Portability: Consider whether you need a tool that can be easily moved or used in various locations.
5. Budget: Balance the cost of the tool against the frequency and importance of your metal-cutting needs.

Design Tips for Laser Cutting Parts

For effective and efficient use of the laser cutting services for your parts. You need to adhere to the below sets of tips for your laser cutting product design.

Your Details Can’t Be Smaller Than Metal Thickness

Thickness is an important factor that you must consider in laser cutting operations. It relates directly to the power of the laser. Therefore, the higher the thickness, the less able the laser can penetrate and cut the material. However, increasing the power of the laser at times might increase the likelihood of cutting such material.

Remember the Kerf

The design of the laser makes it important to note what people call Kerf. Kerf is the material that evaporates when the laser beam hits the laser cutting material. It is not only in laser cutting. It is visible in other subtractive machining processes. Kerf laser cutting occurs due to the thickness of the laser beam. It is an important thing to factor in during the designing stage.

Choose the Right Material

The right material is the most important thing to note before a laser cutting operation. Choosing a material depends on the properties you want the end product to have. For example, materials have different properties in terms of rigidity, translucency, and flexibility. At Rapid Direct, you will have access to different sheet metal laser cutting, plastics, paper, etc.

Spacings Are Important 

Spacing is very important in laser cutting to remove the error and get the best result possible. The minimum spacing should be equal to the thickness of the material. For example, in sheet metal laser cutting, if sheet metal is 2 mm thick, the spacing between two paths be 2 mm. It is also important if you are looking at working on different laser cut sheet metal designs.

Convert Your Text Into Anchor Points and Curves

Not all laser operations require text cutting. However, if you need to incorporate text, you should space the letters of text and write them in large format. This is for a smoother operation and the best result. If the letters are close, they can overlap, leading to an illegible inscription.

Techniques for Cutting Different Metal Forms

Different metal forms require specific cutting techniques to achieve the best results. Here are some tips for common metal-cutting tasks.

Cutting Sheet Metal

Cutting sheet metal requires precision and the right approach. Take the following steps when cutting sheet metal:

1. Mark your cutting line clearly with a permanent marker or scribe.
2. For straight cuts, use a straight edge as a guide.
3. When using power tools, start the cut at the edge of the sheet and maintain a steady pace.

For intricate cuts, consider using a jigsaw with a metal-cutting blade or a plasma cutter for thicker sheets. Remember to wear gloves to protect your hands from sharp edges, and always support the sheet metal properly to prevent bending or warping during cutting.

Cutting Pipes and Tubes

Cutting pipes and tubes requires a different approach than sheet metal.

1. Mark the entire circumference of the pipe before cutting to ensure a straight cut.
2. Use a vise or pipe clamp to secure the pipe and prevent vibration during cutting.
3. Use a pipe cutter for clean, precise cuts on small-diameter pipes and a reciprocating or band saw for larger pipes.

After cutting, use a deburring tool or file to smooth the cut edge and remove any internal burrs that could restrict flow in plumbing applications.

Cutting Metal Roofing

Cutting metal roofing requires care to avoid damaging the material or creating unsafe edges. Here are the steps you should take when cutting metal roofing:

1. Measure and mark your cutting line on the underside of the roofing panel.
2. Use tin snips for small cuts or corners and a circular saw with a metal-cutting blade for long, straight cuts.
3. Cut with the painted side down to minimize damage to the finish.
4. Use steam cleaning to remove any metal shavings or debris after cutting to prevent rust.

Always wear gloves and eye protection when cutting metal roofing, as the edges can be extremely sharp.

Should I Invest in a Laser Cutting Machine or Choose a Service

From simple equipment fabrications to large companies – like the aerospace and automotive industries – laser cutting services are crucial for various manufacturing operations. The technique is an effective and highly efficient procedure suitable for a vast array of materials.

However, the smart choice for small-scale manufacturing companies is to choose a service rather than investing in the machine, as it is an excellent way to save cost yet offer quality to customers. However, if the funds are available, investing in laser cutting machines could be highly profitable because of the numerous advantages that come with the device.

Anyways, the choice is solely dependent on manufacturers. But should you choose to hire a service, contact Krrass – an expert in providing sheet metal laser cutting services.

Your Online Laser Cutting Services for Sheet Metal Parts

Are you looking for a company that guarantees quality laser cutting services? Then, Krrass is just what you need for your fabrication.

We are a trusted company providing sheet metal fabrication services for rapid prototyping and custom production. We guarantee high-quality sheet metal laser cutting services, and we provide cost-effective and on-demand solutions as per your request.

Alternatives to Laser Cutting

Perhaps you do not want to use laser cutting and are unsure of how to cut shapes out of sheet metal; below are other high-end options for your manufacturing needs.

EDM

EDM, Electrical Discharge Machining, like laser cutting, uses thermal energy to remove pieces of material. It uses electrical discharges (sparks) to cut out the desired shape from a material. Compared to laser cutting, EDM produces a better surface finish with a less heat-affected zone. Also, it is suitable for cutting hardened pieces of material.

CNC Milling

CNC milling involves using high-speed rotary cutters to shape materials. Milling operations function well in metals, alloys, and nonmetals. Like laser cutting, they are a high precision subtractive manufacturing process. The main difference between the two processes is that while milling uses cutting tools – rotating cutters, to carve out or shape designs, laser cutting uses beams of lights, laser melt, or burn out design shape.

Waterjet Cutting

Water jet cutting is a manufacturing technique that involves using water or a mixture of water and abrasive substances under high pressure to cut a piece of material.

Below is a comparison between water jet cutting and laser cutting.

• Laser cutters can engrave numbers or marks, whereas water jet cutting allows only cutting.
• Both are suitable for cutting a wide range of materials. However, water jets can’t cut thicker materials than laser cutters, up to 50mm.
• Laser cutting has better tolerance levels and pays more attention to intricate details, which makes them the better choice for complex geometries.

Punching

Punching uses a punch press to cut out the desired shape from a piece of material. Like other CNC operations, punching is a highly precise technique for parts fabrication, and it is also suitable for a vast range of materials. However, punching is not ideal for fabricating components with complex geometries.

Conclusion

Laser cutting is a technology used in rapid prototyping for cutting materials. This article introduced the operation, its history, types, and other things you might know. We believe that you’ve learned one or more things about laser cutting. However, you can trust us at Krrass for the best laser cutting services.