Sheet metal laser cutting is now one of the most accurate and flexible methods in modern manufacturing. However, many first-time buyers still face common problems. These include unclear drawings, choosing the wrong materials, or missing tolerance details. Such mistakes often result in delays and increased costs.
This article explains how to avoid these issues before placing your order. It covers how the laser cutting process works, how to select the right materials, define proper tolerances, and plan surface finishes. Each section gives simple, practical tips to help you achieve accurate results at a reasonable cost.
Comment fonctionne la découpe au laser？
Laser cutting is a method that uses a focused light beam to cut metal sheets with high precision. The laser’s energy melts or vaporizes the material along a set path, creating clean, smooth edges. A computer-controlled system moves the beam based on your CAD file, enabling the accurate production of even complex shapes, fine holes, and sharp corners.
The process starts when a design file, usually in DXF or STEP format, is uploaded to the machine’s software. The software converts the design into cutting paths. Then, the laser head moves across the sheet, focusing the beam to a tiny point. The focused beam reaches extremely high temperatures, melting the metal instantly along the path.
After cutting, the parts are separated from the sheet. Any small burrs are cleaned off. Because the beam is so narrow, the kerf—the width of the cut—is minimal. This helps reduce material waste and ensures precise edges.
Types of Laser Cutting Machines
There are three main types of laser cutting machines: fiber, CO₂, and YAG. Each type has its strengths and ideal uses.
Fiber laser cutting uses a solid-state laser transmitted through fiber optics. It is highly efficient and ideal for reflective metals such as stainless steel, aluminum, brass, and copper. Fiber lasers provide fast cutting speeds, low maintenance, and excellent precision.
CO₂ laser cutting uses a gas mixture of carbon dioxide, nitrogen, and helium. It creates smooth edges and can cut both metals and non-metals, such as plastic, wood, and acrylic. It works best for mild and stainless steel of medium thickness, but is less effective on reflective metals like aluminum or brass.
YAG laser cutting is less common for sheet metal, but it is useful for marking or drilling fine features. It can handle thin metals and special materials, though it usually operates at slower speeds than fiber lasers.
Preparing Your Design Files
Accurate design files are the foundation of precise laser-cut parts. Proper formatting and clean layouts help prevent errors and keep production on schedule. Here’s how to prepare your CAD files to ensure a smooth cutting process.
Accepted File Formats
Most laser cutting systems use CAD files directly. The most common formats include DXF, DWG, STEP, IGES, and AI.
DXF and DWG are ideal for 2D cutting. They define contours, holes, and slots using vector lines. These formats ensure accurate outlines for flat sheet metal parts.
STEP and IGES work best for 3D models. They allow engineers to view the whole geometry and create flat patterns for bending or folding sections. These formats are handy for parts that require a combination of laser cutting and forming.
AI (Adobe Illustrator) files are suitable for simple flat designs such as panels or signs. Before sending them, make sure the paths are clean, vector-based, and free of overlaps.
When exporting, keep the drawing at a 1:1 scale and delete any hidden or duplicate geometry. Save each part as a separate file, and label it clearly with the material type and thickness. This helps engineers review your files quickly and avoid mistakes during setup.
Design Tips for Smooth Cutting
Small design details can significantly affect cutting accuracy. Follow these simple rules to improve results and minimize rework.
- Minimum feature size: Avoid features smaller than the laser beam width, typically 0.1–0.2 mm. Tiny holes or thin slots may melt or distort. As a guideline, set the minimum hole size equal to the material thickness.
- Kerf compensation: The laser removes a narrow strip of material, called the kerf, along its path. This width depends on the material and laser type, typically ranging from 0.1 to 0.3 mm. Check whether your manufacturer adjusts for kerf automatically, or offset your design to maintain accurate dimensions.
- Hole-to-edge distance: Place holes or cutouts at least one material thickness away from the outer edge. If they are too close, heat can cause warping or weak areas. For thicker or heat-sensitive materials, increasing the distance improves part strength and stability.
Choosing the Right Metal Material
Every metal behaves differently under the laser. Understanding how each material cuts and how thickness affects quality helps you choose the best option for your design.
Common Material Options
Aluminum is a lightweight, durable, and corrosion-resistant material. It’s often used for enclosures, panels, and electronic housings. Aluminum cuts quickly but reflects light, so fiber lasers are the best choice. Thin sheets, ranging from 1 to 4 mm, cut cleanly and leave bright, smooth edges.
Stainless steel combines high strength, corrosion resistance, and an attractive finish. It’s widely used in medical devices, food equipment, and outdoor products. Both fiber and CO₂ lasers can cut stainless steel, producing smooth edges with little to no burrs.
Carbon steel (also known as mild steel) is strong, affordable, and easy to process. It’s the most common option for brackets, frames, and general fabrication. Fiber and CO₂ lasers both work well, particularly when oxygen-assist gas is used to enhance cutting speed.
Brass offers a decorative look and resists corrosion, making it popular for signage and architectural panels. Because brass reflects laser light, fiber lasers are more effective for cutting it than CO₂ lasers.
Material Thickness and Its Impact
Material thickness has a significant influence on cutting results. Thin sheets cut faster and leave smoother edges, while thick sheets require more power and slower movement.
For example, a 1 mm stainless steel sheet cuts almost instantly with a clean, mirror-like edge. A 6 mm sheet, however, needs higher power and a slower speed to cut through completely, which can slightly dull the edge.
Thicker materials also hold more heat, increasing the chance of warping or discoloration—especially in small parts. Using support grids and the right assist gases helps control heat and keep edges clean.
In terms of cost, thicker sheets require longer cutting times and consume more energy, making them more expensive to process. Some manufacturers charge by cutting time, meaning optimizing your design and material thickness can save both time and money.
Defining Tolerances and Dimensional Accuracy
Good precision depends on how tight the tolerances are and how stable the cutting conditions remain. Understanding what laser cutting can achieve—and what can affect it—helps you design parts that fit perfectly and stay within budget.
Typical Laser Cutting Tolerances
Modern laser cutting machines can achieve tolerances around ±0.1 mm for most sheet metal parts. For fragile sheets or simple shapes, accuracy can be as high as ±0.05 mm. These levels are more than enough for most brackets, panels, and enclosures.
If your design requires very tight fits or highly detailed features, additional machining may be necessary. Tolerances tighter than ±0.05 mm often need secondary processes such as milling, reaming, or grinding. These help refine small holes, slots, or critical edges that the laser alone cannot perfect.
When setting tolerances, it’s best to specify them only where they truly matter. Applying tight tolerances everywhere increases both cost and production time. Keeping functional areas strict and allowing looser limits elsewhere maintains precision without unnecessary expense.
Factors Affecting Accuracy
Several factors influence how closely a laser cutter can match your design dimensions.
Machine calibration is a key element. Regular calibration ensures the beam is perfectly aligned and focused, maintaining consistency in every cut. Even small misalignments can cause uneven edges or slight variations in shape.
Material flatness also affects accuracy. If the sheet is bent or uneven, the laser may lose focus, which can alter the kerf width and cut depth. Using flat, leveled material stock helps maintain consistent results.
Thermal expansion is another factor. The laser’s heat can cause the metal to expand slightly while cutting. When the part cools, it contracts again, sometimes leading to small dimensional shifts. This effect is more pronounced in thicker sheets and materials, such as stainless steel, which retain heat for a longer period.
Selecting the Right Surface Finish
The surface finish determines both the appearance of your part and its long-term performance. Choosing the right finish improves durability, appearance, and corrosion resistance. Here are the most common finishing methods, along with guidance on when to apply them.
Common Finishing Processes
Anodisation is widely used for aluminum parts. It creates a hard, protective oxide layer that prevents corrosion and can be dyed in many colors. This finish improves both appearance and wear resistance, making it ideal for electronic housings, decorative panels, and outdoor components.
Revêtement en poudre utilizes an electrostatic process to apply dry powder, which is then cured through baking to form a strong, even layer. It works on steel, stainless steel, and aluminum. Powder-coated parts resist scratches, rust, and fading, and they come in a wide range of colors. It’s commonly used for machinery covers, enclosures, and consumer products.
Polissage smooths and brightens the surface, giving it a reflective look. It’s often applied to stainless steel for a clean, mirror-like appearance. Polishing also removes minor defects and improves hygiene, making it suitable for medical, food-grade, and decorative applications.
Brossage imparts a delicate, linear texture to the metal using abrasive belts or pads. It reduces glare and creates a soft, matte finish. This type of finish is popular for control boxes, panels, and appliances where a uniform and professional appearance is desired.
When to Finish Before or After Cutting？
Finishing can be done either before or after laser cutting, depending on the design and visual requirements.
Pre-finished materials—like anodized aluminum or brushed stainless steel—are convenient when minor heat marks near the edges are acceptable. They save time and eliminate extra steps after cutting. However, cutting through coated or painted layers can sometimes leave slight edge discoloration.
For parts that must look perfect, post-processing after cutting is the better choice. It removes any burrs, oxidation, or heat stains that may occur during the cutting process. Post-finishing also ensures that coatings or treatments cover all surfaces evenly, including the edges and cut holes.
Optimizing Your Order for Cost and Lead Time
Small design and planning changes can make a big difference in cost and speed. Here’s how to order smartly and get faster, more affordable results.
Batch vs Prototype Orders
Laser cutting requires setup work, including file preparation, machine calibration, and sheet positioning. These steps take about the same time whether you’re cutting one part or hundreds. That’s why prototype orders usually cost more per piece—the setup cost is shared among fewer parts, and small runs often need more manual handling or adjustments.
Batch orders, on the other hand, are far more efficient. Once setup is complete, the machine can run continuously, cutting many parts with minimal supervision. This lowers the cost per unit and ensures consistent quality across the entire batch. For larger production runs, this efficiency makes a big difference in both time and budget.
Design-for-Manufacturing Tips
A good design not only looks right but also helps reduce production costs. Here are a few ways to make your parts easier and faster to cut:
- Simplify geometry. Avoid overly detailed shapes or unnecessary decorations that add extra cutting time. Straight lines and smooth curves cut more efficiently, reducing heat buildup.
- Group similar parts. Combine components made from the same material and thickness in a single cutting job. This limits material changes and shortens setup time.
- Use efficient nesting. Nesting means arranging parts on the sheet to use as much material as possible. Leave a small gap—around 1–2 mm—for the kerf and heat control. Good nesting reduces scrap and saves on raw material costs.
- Add small tabs or micro-joints. These keep parts attached to the sheet during cutting, preventing them from tipping or shifting. It helps maintain cleaner edges and reduces the need for rework.
- Avoid tight corner radii. Sharp corners take longer to cut and wear the nozzle faster. Adding small fillets makes cutting smoother, extends tool life, and improves edge quality.
Why Work with Shengen for Custom Laser Cutting？
When precision, speed, and reliability are crucial, selecting the right manufacturing partner is essential. At Shengen, we provide complete support—from design review to final production—ensuring every part meets your exact requirements with consistent quality you can trust.
Our engineering team carefully reviews every CAD file before cutting begins. They verify dimensions, tolerances, and edge spacing to ensure each part is optimized for smooth cutting and precise assembly. This early-stage review helps prevent errors that could lead to production delays or extra costs.
We also give practical design suggestions to make your parts easier and more cost-effective to produce. Whether it’s adjusting hole sizes for cleaner cuts or optimizing nesting layouts to minimize material waste, our engineers provide solutions that save time and resources. You’ll receive clear feedback before fabrication begins, ensuring your parts are accurate on the first run.
Upload your CAD drawings today for a free DFM review. Our engineering team will evaluate your design for manufacturability and provide a quick, accurate quote for your custom metal laser cutting project.
Hey, je suis Kevin Lee
Au cours des dix dernières années, j'ai été immergé dans diverses formes de fabrication de tôles, partageant ici des idées intéressantes tirées de mes expériences dans divers ateliers.
Prendre contact
Kevin Lee
J'ai plus de dix ans d'expérience professionnelle dans la fabrication de tôles, avec une spécialisation dans la découpe au laser, le pliage, le soudage et les techniques de traitement de surface. En tant que directeur technique chez Shengen, je m'engage à résoudre des problèmes de fabrication complexes et à favoriser l'innovation et la qualité dans chaque projet.
