Cutting Services

The Laser Changes the Material
Anyone who uses a laser to process parts must realize that a high-intensity light source used to generate a laser beam is so hot that it melts metal in a millisecond.any part processed with a laser is exposed to extreme heat and will have a heat-affected zone (HAZ) along the edge of the cut.

Watch for the Taper
All laser-processed parts have a taper of some degree because the focused laser beam is not perfectly straight, but rather is shaped like an hourglass. In thin material the taper is so minimal that it is not an issue. The taper starts to show in material 0.50 in. and thicker.
Fabricators concerned about taper should be aware that machine tool builders have developed new technology that improves the cut quality and speed, while reducing the amount of taper in thicker material. For example, a new nozzle technology is being used to funnel the cutting gas to the cut itself rather than allowing it to spread over the material. Also, beam modulation is being used to improve the cut edge quality.

Be Aware of Bend Reliefs
One of the best advantages of using a laser to process sheet metal is that it can create just about any shape required. The only limitation is part size, although it is amazing how small laser-cut parts can be.
One consistent part design error is improper bend reliefs drawn into parts.
Often in thin-gauge material, these reliefs are simply too thin to achieve a good cut straight off the laser. The problem occurs because the assist gas travels the path of least resistance, which is the first segment of the path the laser takes.
As the laser travels back up the other side of the relief, the melted material is not ejected properly, which results in dross forming on the relief edge.
That dross gets in the way of the bend. The part must be redrawn so that the laser can process it correctly.

Put the Pierce in Its Place
Piercing through material with a laser has greatly improved compared to how it worked in the early years. Fabricators now can use various piercing methods to process their parts. These include fast piercing; slow, gentle piercing; and multi-stage piercing. The gentle and multistage pierces are designed to minimize the amount of splatter that can land on what will be a finished part.
Optical sensors are also being used to determine the moment that the laser has penetrated the material so that the cutting can begin. This feature helps to reduce the production time of parts.
Because a finished part’s appearance is often important, a laser programmer has to place the pierce point in an ideal location. One of the best places to put the pierce is in the middle of a small slug of material. Placing it there greatly reduces the risk of pierce splatter and the heat effect in thicker material.
What happens when the pierce is in the wrong place? Consider a pierce that is placed 1⁄4 in. away from what will be the hole edge in 1⁄2-in. mild steel. If the pierce point is placed close to the edge that will be cut, heat or splatter from the pierce could affect the quality of the cut or even cause the cut to be lost. By moving the pierce point away from the edge, the design engineer circumvents those issues.

Will the Parts Be Powder-Coated
If a part is to be powder-coated, a fabricator has to keep a few things in mind. The most important issue is what assist gas should be used to cut. If oxygen is used, a secondary process such as tumbling or an acid bath will be required to remove the oxide layer that forms on the edge of the part during laser cutting. If that oxide is not removed prior to powder coating, the cured powder finish eventually will flake off because it is attached to the oxide layer and not the metal itself.
To eliminate the need to remove the oxide layer, fabricators can cut with nitrogen as the assist gas because it yields a clean cut. With nitrogen gas cutting, the more power the laser has, the thicker the material that it can process. Increased speed comes along with increased power. The operator should be aware of the power level of the machine to know the maximum thickness that can be cut cleanly.
Depending on the laser power, a fabricator also needs to consider the machine’s ability to process a material with the desired end results. If, for example, a company wants to purchase a laser to clean-cut 0.1875-in. steel that will be powder-coated, the company would want to analyze the differences in the finished part when using a 3-kW laser cutting machine as opposed to 4-kW equipment. The greater power level of the 4-kW machine may give them the results they want to achieve without nitrogen. The 3-kW machine may require the use of oxygen as the laser assist gas to obtain a dross-free part.

Material Thickness May Not Matter Anymore
Flat sheet laser cutting machines are really making strides in their ability to process materials. Today’s solid-state laser cutting technology processes thin material very quickly. For instance, an 8-kW solid-state laser cutting machine can cut 0.039-in.-thick steel at a speed in excess of 2,000 inches per minute (IPM).
Even for thick plate, fabricating technology developers continue to increase the speed at which fabricators can cut. Using the latest solid-state cutting technology, fabricators can cut 1-in. mild steel at speeds greater than 35 IPM. For that material especially, the speed has improved compared to what was possible even just a few years ago. The cut edge quality also is improved greatly.
The latest laser cutting technology also can process up to 1-in. aluminum and 2-in. stainless steel. For reflective material such as brass and copper, these lasers can cut up to 0.38 in. thick without beam reflection issues.

The Part Shape Affects Cutting Efficiency
Solid-state laser cutting technology has increased the machines’ cutting speeds and reliability, but it has not changed the way people think about designing parts. Whether cutting with a traditional CO2 laser or a solid-state laser, a fabricator should take the same considerations into account to increase the reliability of the cutting process and to get the best end result.
If a part is engineered with 90-degree corners, the cut time can increase and the part quality decrease. Because the laser cutting head has to decelerate as it takes the sharp corner, it can overburn the corners, causing dross to form. It might even burn away the corners entirely.the larger the radius a design engineer is able to allow, the better. This enables a fabricator to increase the cutting speed and part quality.

CO2 Lasers
CO2 lasers are among the sheet metal cutting industry’s most widely used laser systems. These lasers operate by electrically stimulating a carbon dioxide gas mixture.
CO2 lasers are highly efficient and can cut through various materials with high precision, including non-metallic and metals. They are particularly effective for cutting thicker materials and are prized for their excellent beam quality and cutting speed.

Fiber Lasers
Fiber lasers represent a newer class of laser technology, where the laser beam is generated by a solid-state gain medium—an optical fiber doped with rare-earth elements such as ytterbium. These lasers are known for their high energy efficiency, lower maintenance requirements, and longer service life than CO2 lasers.
Fiber lasers excel at cutting reflective metals like aluminum and copper without the beam reflectivity issues that CO2 lasers encounter. They can also achieve very high cutting speeds, especially on thin and medium-thick metals.

YAG Lasers
Neodymium-doped Yttrium Aluminum Garnet (Nd: YAG) lasers are another type of solid-state laser. They are used for applications requiring high power and the ability to cut through thick metal plates.
YAG lasers can be operated in continuous and pulsed modes, making them versatile for different cutting operations. They are less common than CO2 and fiber lasers for metal cutting but are often used for high-precision cutting in the electronics and medical industries.

Diode Lasers
Diode lasers use semiconductor technology to produce laser light. While generally not as powerful as CO2 or fiber lasers, diode lasers are used in applications requiring delicate and precise lightweight Cutting or marking.
They are more energy-efficient and have a smaller footprint, making them suitable for integration into portable cutting equipment or compact machinery.