Manufacturing businesses are evolving everyday and now it’s not just about creating things, it’s also about fixing them. Now comes the opportunity to improve various operations with the help of a brilliant technique: laser metal deposition welding. The process enables businesses to produce components more quickly, with less material wasted and higher quality.
This post will explain everything about laser deposition welding. We will help you understand its types, functioning and benefits. Let’s continue!
What Is Laser Metal Deposition Welding And How Did It Emerge?
One of the newest subfields of metal 3D printing is laser metal deposition (LMD). This is also known as a branch of DED (direct energy deposition). Welding wire is one of the main raw materials used in W-LMD technology.
If we go back to the inception of 3D printing metal- the print did not match the qualities of “real” metal. The first metal printing experiments and devices (DMLS) emerged in the 1990s. This technology was based on melting powder of different alloys with variable thermal properties.
The first premium metal 3D prints were created in the early years of this century’s first decade. During that period, Binder Jetting and Direct Energy Deposition (DED) emerged, the latter using a wire-based process. This is known as Wire Laser Metal Deposition, and the former is based on the sintering of metal powder.
Two Main Types of Laser Deposit Welding
There are various kinds of laser welding methods. Each has its own benefits, restrictions, functions, and uses. Here, we will discuss two different kinds of laser welding.
Manual Laser Deposition Welding
When using manual deposition welding, the filler material is guided “by hand” to the welding spot. In this procedure, filler material is mainly a thin wire with a diameter of 0.15 to 0.6 millimeters. The wire melts under the laser beam. A tiny elevated region is left behind as the molten substance solidifies. It makes a strong bond with the melted substrate.
The welder keeps going until the required shape is obtained, spot by spot, line by line, and layer by layer. The work process is protected from the surrounding air by argon. The part is ground, lathed, milled, EDM, etc., to return it to its original shape.
Automatic Laser Deposition Welding
In automatic laser welding, the laser head has multiple nozzles. These move with precision using a control system, ensuring accurate welding. The nozzles spray fine metal powder and a protective gas onto the spot where the laser hits, melting the filler metal onto the base material. This creates a strong weld without any gaps, making it very durable.
People often use automatic laser welding to add tough layers onto metals, making them more resistant to scratches and corrosion. When this process builds up layers continuously on a material, it’s called additive manufacturing, which is a big part of laser metal deposition. Welding is just one step in this process.
How Does Laser Deposition Welding Work?
Before activating the laser, a lot of preparation is necessary for the intricate process of laser deposition welding. These are a few of the most important steps in the procedure.
Step 1 – Surface Preparation
Surface coatings protect metal billets and ingots. Typically, oils are used as coatings to avoid rust, metal plating, or oxides (in the case of aluminum). To improve metal adhesion during welding, undesirable compounds and impurities must be removed from the metal and roughened. The surface’s microscopic pits and bumps make perfect anchor places for the molten filler metal.
Step 2 – Filler Metal Delivery
Usually a fine metal powder, the filler metal is released via an air nozzle together with an inert gas (argon or nitrogen). Inert gases maintain clean, slag-free welds by preventing oxidation. Also, the operator needs to work on expelling undesired surface contaminants. The process of producing consistent, fine metal powders is costly. It usually takes more work to create the metal powder.
Consequently, tiny metal wires are used in many laser deposition devices in its place. The wire can be fed mechanically or manually using a roller and motor system located close to the laser head.
It should be remembered that in the process of welding, the surface coating may differ from the filler metal even though they are both the same.
Step 3 – Localized Laser Heating
An accurate CNC system directs a strong laser beam to the intended spot. In less than a second, the laser melts the incoming filler metal and the workpiece surface.
The laser beam injects a predetermined amount of energy into the workpiece, and the spot diameter and laser source wattage regulate the energy deposition area. The size of the point of contact between the laser and the workpiece is known as the laser spot diameter. When the spot size is higher, the energy is more dispersed and takes longer to melt the surface. All of the laser’s energy is focused on a small area, and because of the reduced spot diameter, melting time is shortened.
Smaller spot sizes are associated with more precision and quicker welding times. There will be less material deformation because the heat is localized at a single location and no surplus heat is transferred to the surroundings.
Step 4 – Layering and Multiple Passes
Beyond welding, laser metal deposition (LMD) is frequently utilized to manufacture components from the ground up. The laser head makes a second pass after the first laser pass to deposit a fresh layer of material on top of the first. The operator needs to keep doing this until they reach the desired height.
In additive manufacturing, layers are added until the entire part is constructed. In contrast, welding only needs one or two layers. The number and thickness of layers help regulate the quantity of metal deposited.
Step 5 – Cooling and Solidification
Due to the localized nature of the heat, the welded area also cools rather quickly, nearly instantly, after the laser leaves the place.
Energy is directly deposited into a small area on the workpiece during the LMD process. Smaller contact points result in more energy being used effectively.
Overall, less energy and heat are put into the workpiece by a quicker laser. Faster cooling results from less heat buildup. Improved microstructure is an additional benefit of rapid cooling.
Benefits of Laser Metal Deposition Welding
Laser metal deposition, or LMD, is the culmination of several years of study on additive manufacturing technology. The sole objective behind designing every facet of laser metal deposition is to improve conventional procedures. These are a few of the main advantages that laser deposition welding offers to contemporary production techniques.
Faster Welding Times
Extremely short welding times are achieved by the high-power laser’s rapid melting of the workpiece. The CNC controller also contributes with quick movement of the laser head from one spot to another. Automatic table feeding makes continuous welding without any stops possible.
Additionally, computer-controlled welding reduces mistakes and increases production floor time savings. By controlling and adjusting several process laser metal deposition parameters, welding efficiency can be increased, and production time can be decreased.
Higher Precision and Control
There’s a transformation in manufacturing because of laser metal deposition (LMD) welding, which provides unparalleled control and precision. In contrast to conventional welding techniques, LMD uses a focused laser beam with computer guidance. This makes it possible for even an average welder to create precise welds on fragile objects, something that was previously impossible. LMD is perfect for complex geometries and high-value components because of its speed and accuracy.
Higher Quality Welds
As the filler material’s tiny powder particles fill gaps more effectively, a stronger weld is produced. The entire process is computer-controlled and pre-measured. That’s why the amount of metal deposited is precisely what is required, maintaining a constant molten pool throughout. Internal jets are also utilized to remove tiny pieces of vaporized metal and to stop slag formation and metal oxidation.
Zero Distortion from the Heat Source
Traditional welding methods introduce large amounts of undesired heat into the base material. The solder junction receives just a limited amount of heat. The rest drains into the surrounding air and causes the metal to distort.
In the incredibly accurate process of laser metal deposition, only a tiny fraction of the workpiece is melted by the laser beam. The method’s high efficiency makes it a popular choice for full-surface welds. It’s also prized for its minimal concern about material distortion. Coating a material with another material or materials increases wear resistance and surface polish. This process is known as surface welding.
Reduce Material Waste
Laser welding highly promotes reduced material waste. To prevent excessive or insufficient deposition, metal powder is injected into the workpiece at a regulated feed rate. Laser deposition welding employs continuous wire and powder particles as opposed to traditional welding, which needs a filler rod. Just use the necessary amount of filler; save the remainder for the subsequent weld.
In The End
Laser metal deposition welding is a revolutionary process in contemporary manufacturing. This technique, which uses modern technology, combines accuracy and effectiveness. We at Fiber Laser Welder lead this change by offering the best portable laser welding equipment. Your production processes will reach new heights because of our dedication to perfection.
Durable constructions and complex designs are no longer challenging because of laser metal deposition welding. With Fiber Laser Welder, you may enjoy the seamless progress of quality, efficiency, and precision in manufacturing. Discover creativity with us!
