Laser cutting machines have come a long way since they first became available for commercial use. The current ones can easily adjust their operating parameters and cut through medium and thick plates of steel alloys like carbon steel. Even then, it’s not a guarantee that the laser will do a good job.
Let’s take a look at some of these problems and their solutions. When you need help with your laser cutting or other metal fabrication projects, contact the experienced team, ready to help, at Glenn Metalcraft.
Unfamiliarity With Cutting Parameters
Laser cutting is markedly different from plasma cutting. Five factors determine how the machine will cut the stainless steel for sheet metal fabrication. They include:
- Beam focus
- Beam power
- Gas feed rate
- Gas pressure
- Nozzle alignment
Modern machines are advanced enough to control the laser beam characteristics. The beam focus and power are crucial for cutting different types of steel alloys with diverse strengths, thicknesses, and grades.
The operating technicians will need to check on the other parameters, depending on the laser used. These include the centering of the nozzle, beam delivery system, and alignment.
Getting a good cut implies taking into context all the factors and adjusting them according to the material you are attempting to cut. While imperfections during steel fabrication are normal, it doesn’t mean you should tolerate them. Instead, familiarize yourself with the cutting parameters.
Being oblivious of these cutting parameters produces sheet metal with imperfections that could become costly.
Problems Brought About by Mixed Characteristics
While getting the right mix to these parameters is not exactly a science, they have to be in the right proportions; otherwise, various issues will arise. Stainless steel laser cutting is all about striking the right balance between the material heated by the laser beam and the gas flowing through the cut.
If not done right, the following common issues may appear.
Large Heat Affected Zones
Cutting metal requires energy, which converts to heat during the cutting process. By using a laser beam, heat is the medium for cutting steel. Since steel is a good heat conductor, the heat transmits away from the point of contact between the laser and the metal.
A zone forms between the melted metal and the unaffected one during the process. In this area, the microstructure and metal strength are compromised. A large heat-affected zone (HAZ) signifies having a large area of potential weakness.
While laser cutting has the smallest heat-affected zone of all methods used to cut steel, it doesn’t eliminate the problem. The adequate gas flow between the cut and additional cooling can help reduce the formation of an HAZ.
Striations are periodic lines that pop up on the surface of a cut in waves. They are undesirable as they affect the final products‘ appearance, surface roughness, and precision. The formation of striations results from the melting and cooling process when the type of gas can influence the cutting method in use.
It’s impossible to get rid of striations, but decreasing them to a minimal size is possible. You can reduce striations by having a moderately adequate cutting speed. The minor temperature variation provides an almost even heating and melting phase.
Burrs are created as a laser cuts through the metal by melting the portion it is going over. The gas then pushes the molten metal from between the kerf, solidifying it under the sheet metal.
Burr formation is impacted by several things, including the sheet metal’s thickness and the type of gas employed. If using nitrogen, the beam is solely responsible for all the energy to melt the metal. Instead of utilizing oxygen, the gas interacts with the heated metal, resulting in an exothermic reaction. This brings about more heat, adding to burr formation.
Though melting the metal is the mechanism for cutting it, regulating the gas pressure is vital to ensuring a high-quality cut. Excess gas pressure is responsible for burr formation and the reason why when using oxygen, gas pressure is lower.
Considerations When Using Oxygen
You have to consider several things if you decide to cut carbon steel using oxygen. This is because oxygen results in an exothermic reaction, and the purity level becomes an influencing factor. Purity above 99.95% indicates that you can significantly increase cutting speed and improve production statistics.
The problem comes in when the purity drops, mostly when changing cylinders or switching to one with impurities such as Argon. When you introduce the new gas to the process, you have to change the controlled exothermic process, and the outcome is a reduction in cutting performance.
Looking For Innovative Solutions To Your Manufacturing Problems?
Then you’ve come to the right place. At Glenn Metalcraft, we specialize in precision metal works such as heavy gauge metal spinning, laser cutting, and plasma cutting. Request an estimate and see how we can partner to solve your metal fabrication problems.