Laser Cladding

Why are so many companies selecting laser cladding today?

Today laser cladding is an important cost savings tool as it significantly increases the lifetime of high performance components and at the same time reduces the use of rare and expensive metal materials.

How does laser cladding compare to other cladding technologies?

The increasing popularity of laser cladding compared to conventional technologies such as thermal spraying (HVOF, Plasma, Cold Spray etc) and arc overlay welding (PTA, TIG etc) is driven by characteristics such as:

  • The high performance alloy is melted with minimal dilution of the lesser substrate material, thus preserving the qualities of the performance alloys.
  • The melt metallurgical bond between the completely dense performance alloy and the substrate is extremely strong and free of defects.
  • The heat input into the substrate is minimal thus not damaging important properties or causing heat related distortion.

What is dilution in laser cladding?

Since laser cladding produces a metallurgical bond, there is a certain degree of mixing between the base metal and the alloy material. This mixing is called dilution, and it reduces the purity of the cladding alloy. Keeping dilution at a minimum and solidly below 5% is an important characteristic of a high-quality laser cladding layer. In many applications the low dilution allows the engineer to work with just one laser cladding layer while other additive manufacturing technologies require multiple layers to achieve the same results for corrosion and wear protection.

What are commonly used high performance alloys for laser cladding?

The selection from high performance alloys used for laser cladding and laser hardfacing can be overwhelming. Laser Welding Solutions will work with you on finding the right fit of commercially available alloys for your wear application or will assist you in the development of a unique and proprietary solution.

Common alloys for laser cladding and laser hardfacing include:

  • Nickel alloys such as INCONEL 625, INCONEL 718, C276, COLMONOY 6
  • Cobalt alloys such as STELLITE 1, STELLITE 6, STELLITE 21
  • Ceramic reinforced alloys such as our M-Series Tungsten Carbide alloys
  • Diamond reinforced alloys such as our Diamondite-M alloys

What is the typical thickness of a laser cladding layer?

While it is possible to produce laser cladding layers with just a few thousand of an inch in thickness, the typical range for industrial applications is between 0.020" and 0.060" for a single layer. For a wide-range of cladding materials, the stacking of multiple layers allows for the generation of thicker protection layers.

Can laser cladding be used with nickel- and cobalt-based alloys such as Inconel & Stellite to increase corrosion and wear protection?

The short answer is "absolutely"; A more detailed response requires information on the specific wear case, the base material, as well as the geometry of the wear component. Also of importance are the acceptance criteria for the finished laser coating. Is the coating surface required to be completely free of imperfections, and is a minimum micro-hardness required? What is the requested thickness of the laser cladding layer? 

Laser Welding Solutions will work with the customer to answer these questions and develop a weld procedure specification that outlines the best laser processing parameters for the specific wear case and material combinations.

What is laser hardfacing?

The laser hardfacing process is a variation of laser cladding with the same overall characteristics. It is specifically optimized for the protection against wear caused by abrasion, erosion, or impact. The wear resistance is achieved by selecting high hardness alloys for the laser cladding process, such as cobalt alloys (e.g., Stellite 1, 6, or 21).

Other popular laser hardfacing materials used at LWS include tungsten carbide and diamond reinforced alloys for extreme wear protection. Hard particle reinforced alloys benefit from the laser process due to the characteristically well-controlled energy delivery. This way melt pool temperatures are balanced to preserve the hard particle concentration.

What is Laser Metal Deposition?

Laser Metal Deposition classifies as a Directed Energy Deposition process in the group of additive manufacturing technologies. It is a variation of the laser cladding process in which multiple layers are stacked on top of each other to generate a 3-dimensional geometry. Laser Metal Deposition is a very suitable alternative to powder-bed 3d printing for large-area metal components. The process also offers the unique possibility of printing a part with several different metal alloys to optimize wear and corrosion properties in areas where needed. Laser Welding Solutions offers robot-based Laser Metal Deposition with several machines designed for aerospace, energy, and general industry applications.

Can Laser Cladding be used for remanufacturing worn or damaged components?

Laser cladding is an additive manufacturing process. The technology utilizes a laser to melt and bond metal alloy layers to a worn or damaged component. In cases where several cladding layers are stacked on top of each other to restore a geometry and create a 3-dimensional shape, the process is also called Laser Metal Deposition.

The best-known characteristics of the technology are its great precision and low heat impact. Consequently, there are only minimal or even no effects on the un-damaged areas of the part requiring remanufacturing.  Another reason why laser cladding is increasing rapidly in popularity is the wide range of metal alloys available for rebuilding geometries and protecting surfaces. In remanufacturing, the selected materials potentially withstand service wear and tear much better than the original material. Think of seal or bearing surfaces remanufactured with more corrosion or wear-resistant alloys than the original machined component.

In addition, the laser cladding process typically delivers excellent metallurgical characteristics, thus further increasing the lifetime of the component.

How does Laser Cladding compare to other surface technologies such as HVOF spraying or PTA welding?

The best-known characteristics of laser cladding are its great precision and low heat impact. Consequently, there is only minimal or even no effect on the un-damaged areas of the part requiring laser cladding.

In comparison, HVOF or high-velocity-oxygen-fuel spraying is a process that produces a thin coating with a mechanical bond to the substrate over a relatively large area. This cladding layer contains a degree of voids and micro-cracks.

PTA welding is similar to laser cladding. The main distinguishing characteristic is that a plasma flame melts the substrate and additive material instead of the more energy-dense laser beam. Therefore the heating and cooling times are slower, and the total heat input is higher when compared to laser cladding. This heat input causes the weld to penetrate deeper into the substrate and dilute the cladding layer.

While all three technologies are essential in modern manufacturing, laser cladding is rapidly growing in popularity for use with critical components. Its superior cladding layer characteristics and the reduced work for secondary finishing processes make it a cost-effective choice for many high-profile industrial applications. 

Can laser cladding be considered a "green" and "sustainable" technology?

While lasers are relatively expensive and operate with wall-plug efficiencies just approaching 50%, they should still be considered a green technology. The importance of lasers in materials processing for a sustainable future is without question for multiple reasons:

  • Laser welding is one of the most critical enabling technologies for modern battery production today. It provides the ability to join precisely, fast, and with limited heat input for efficient battery designs. Laser welding also provides the ability to join dissimilar materials for new battery generations. 
  • Laser cladding is a process that generates thin protective layers for high-value and critical components in a range of industries from food processing to transportation and energy. It extends the service life of these parts significantly. Laser cladding also allows the engineers to use lower grade steels for the design that are only reinforced locally in crucial areas by the laser process. 
  • Laser metal deposition (LMD) is an additive manufacturing technology that produces 3-dimensional geometries by stacking laser cladding tracks. While it is a relatively new technology, it gains in popularity for the remanufacturing of high-value components. LMD allows a part to be rebuilt and reshaped in the damaged areas only. This way, laser processing saves time and raw materials. 

Laser technology continues to push the boundaries of modern manufacturing and helps us save critical resources for a greener and sustainable future. 

3d Printing

What is Wire- Arc Additive Manufacturing (WAAM)?

Wire-Arc Additive Manufacturing is a technology in the class of directed energy deposition processes. First patented in the 1920s, it remains one of the least known processes in the additive manufacturing environment but with tremendous potential. WAAM uses an arc source to melt metal alloy wire feedstock to generate 3-dimensional parts. The process itself is simple, but the technology is increasingly powerful when paired with modern CAD/CAM software. WAAM produces near-net-shape geometries without the need for complex tooling, molds, or heavy machining operations. It is a gateway technology for manufacturing on-demand with significant lead time and total cost reduction potential for many applications.

What equipment is typically used by additive manufacturing companies for the WAAM process?

Many companies are using conventional arc welding robot set-ups to generate simple but relatively large geometries. Laser Welding Solutions has chosen a different approach. We entered into a collaboration with GEFERTEC GmbH, a German manufacturer of 5 axis WAAM machines. The GEFERTEC machine pairs a modern low-heat-input arc welding system and the latest Siemens NX software to deliver a powerful 3d WAAM printing machine suited for complex geometries and large build volumes.

What resolution does the WAAM process offer, and how does it compare to powder-bed 3d printing?

Resolution is the accuracy of the printing process in all three dimensions. WAAM technology has a resolution of approximately 1 mm that is significantly impacted by the welding wire diameter. In contrast, the resolution in powder-bed 3d printing can be as low as 0.025 mm. For many applications, the print resolution of the WAAM process does not present any issues since the parts receive a finish machine operation after printing.

What materials are printed by the Wire-Arc Additive Manufacturing process (WAAM)?

In general terms, any metal alloy available as a welding wire can be printed by the WAAM process. The list of available wire materials includes carbon and low alloy steels, stainless steels, nickel- and cobalt-based alloys, aluminum alloys, and titanium alloys.

Many wire manufacturers are currently testing new alloys to extend the available material range for high-strength and high-temperature applications.

The WAAM process can print several materials in one part. This capability is an exciting technology characteristic for many wear- and corrosion applications.

What is the most exciting yet underutilized characteristic of large-scale metal additive manufacturing?

An often underutilized characteristic of large-scale metal additive manufacturing with Directed Energy Deposition technologies such as WAAM is the ability to use multiple metal alloys in one print. Exciting advantages of multi-material printing are:

  1. Cost savings: Multi-material metal printing can potentially lead to cost savings by reducing the need for multiple manufacturing steps and decreasing material waste.
  2. Customization: Multi-material metal printing enables the production of parts with varying properties at different locations, which can be useful for customized or personalized applications.
  3. Improved durability: Combining different metal alloys can improve the durability of a part or component, making it more resistant to wear and corrosion.

What is large-scale additive manufacturing?

Large-scale additive manufacturing (LSAM) refers to the process of using 3D printing technology to create large objects, typically those with dimensions measured in meters or even tens of meters. LSAM typically involves the use of specialized equipment, such as large-format 3D printers, robotic arms, or gantry systems, that are capable of depositing materials in layers to create three-dimensional objects.

LSAM is often used in industries such as aerospace, construction, and automotive manufacturing to create large-scale prototypes, tooling, and even finished products. It can be used with a wide range of materials, including plastics, metals, ceramics, and composites.

One of the advantages of LSAM is that it can significantly reduce the time and cost required to create large objects, as it eliminates many of the steps involved in traditional manufacturing, such as casting or machining. It also enables designers and engineers to create complex geometries that would be difficult or impossible to achieve using conventional manufacturing methods.

How does Additive Friction Stir Deposition (AFSD) work?

During Additive Friction Stir Deposition (AFSD), a solid-state 3d printing process, the material is bonded through a combination of mechanical mixing and metallurgical bonding.

As the rotating tool moves along the tool path, it generates frictional heat and plasticizes the material, causing it to soften and become ductile. The friction stir tool also exerts a significant amount of force on the material, causing it to be mechanically mixed together as the tool is moved along the build up area. This mechanical mixing process results in the formation of a stirred zone, which is characterized by a fine-grained microstructure and a uniform distribution of the original material properties.

As the tool moves forward, the plasticized material behind the tool is allowed to cool and recrystallize, creating a metallurgical bond with the underlying material. This bond is formed due to the diffusion of atoms across the interface between the two sides of the joint, resulting in the formation of a solid-state weld without melting or the addition of a separate filler material.

The strength of the resulting bond depends on a number of factors, including the material properties, the tool design, the process parameters, and the print path configuration. The presence of defects such as porosity, incomplete bonding, or cracking can significantly reduce the strength of the print. Therefore, it is important to carefully control the process parameters and use appropriate tool designs to ensure a high-quality print is produced.

Laser Hardening

When is laser hardening a better choice than induction hardening?

The laser offers minimal heat input and precise control with unique flexibility and low distortion, in a non-contact process where the air-gap, unlike induction, is not critical but line of sight access over considerable distance is possible.

Induction heating is not a “power limited process” like the laser, so treatment times are not so heavily linked to the size of the hardened zone. Tooling changeover times for induction are higher but both methods use piece by piece or “continuous processing” which integrates more effectively with flexible just-in-time manufacturing techniques.

The ability to treat substantial areas/numbers of components is the strength of induction and the ability to treat complex shapes with flexibility and finesse and minimal distortion is the laser’s forte.

What are the most common materials that are laser hardened?

Low and medium carbon steels are commonly laser-hardened for applications that require high wear resistance and surface hardness, such as cutting tools, gears, and dies.

Laser hardening can also be applied to various alloy steels, such as tool steels, high-speed steels, and maraging steels, which are used in a wide range of applications that require high strength and toughness.

Laser hardening can improve the wear resistance and corrosion resistance of stainless steels, which are commonly used in the food, chemical, and medical industries.

Laser hardening can increase the surface hardness and fatigue strength of high-strength steels, such as HSLA (high-strength, low-alloy) steels, which are used in automotive and aerospace applications.

Laser hardening can also be applied to specialized steel alloys, such as spring steels, bearing steels, and nitriding steels, which have specific applications that require high wear resistance and fatigue strength.

Hand-Held Laser Welding

What makes hand-held laser welding such an exciting new welding technology?

Hand-held laser welding is a welding technique that uses a laser beam as the heat source to join two or more materials together. Unlike traditional welding methods that use a flame or electric arc to heat and melt the materials, laser welding uses a focused beam of light to melt and join the materials.

In hand-held laser welding, the laser is mounted on a handheld device that allows the operator to move the laser beam across the surface of the materials being joined. This gives the operator greater control over the welding process and enables them to create precise welds with minimal heat input, resulting in less distortion and improved weld quality.

What are the 5 main advantages of hand-held laser welding for sheet metal applications?

Hand-held laser welding offers several advantages for sheet metal applications, including:

  1. Precise control: Handheld laser welding allows for precise control over the welding process, which is essential for welding thin sheet metal. The operator can easily adjust the laser beam's intensity, size, and position to create a high-quality weld.
  2. High welding speed: Laser welding is a fast process, which makes it ideal for sheet metal applications that require a quick turnaround time. The high welding speed also helps to minimize heat input, reducing the risk of distortion and warping.
  3. Reduced heat input: Handheld laser welding generates less heat than traditional welding methods, such as MIG or TIG welding. This reduces the risk of thermal distortion and helps to preserve the material's mechanical properties.
  4. Weld quality: Laser welding produces a high-quality weld with minimal porosity and a small heat-affected zone (HAZ). This results in a strong, durable weld that maintains the sheet metal's original mechanical properties.
  5. Versatility: Handheld laser welding can be used to weld a wide range of materials, including stainless steel, aluminum, and titanium. This makes it a versatile welding process for sheet metal applications across many industries.