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.
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.
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.