What is the working principle of metal 3D printing in industrial equipment?

The heart of technology: a shift in manufacturing from subtractive to additive manufacturing
The most important part of metal 3D printing is putting metal ingredients down in exactly the right way, which is done directly by digital models. This completely changes the typical "blank processing assembly" cycle of manufacturing. The Platinum BLT-S1500 equipment has a 10-laser synchronous scanning system that lets it print with the highest accuracy of 0.06mm per layer in a forming chamber that is 1.5 metres wide. There are four main steps in its workflow:
Modelling and slicing in digital form: Use CAD software to make 3D models, then use slicing software like Magics to turn them into STL files that can be read. Set the layer thickness to 0.02–0.1 mm dependent on the qualities of the material.
Powder bed pretreatment: The powder spreading equipment evenly spreads spherical titanium alloy powder on the workbench in a vacuum or inert gas environment. The layer thickness is controlled to within ± 5 μ m.
Selective melting with a high-energy beam: The laser galvanometer device moves at a speed of 20m/s over the current layer cross-section, melting the powder into a pool of liquid metal. Marangoni convection then helps the metal get denser and solidify.
Layer by layer stacking moulding: The workbench is lowered by the thickness of one layer, and the cycle of depositing powder, melting, and solidifying is repeated until a metal object with a density close to 100% is made.
This new way of making things has raised the material utilisation rate from 10%–20% in old methods to above 90%. For example, the 3D printed version of GE's wind power main bearing seat is 40% lighter than forged parts and cuts the development time from 18 months to 3 months. The five primary procedures are different from each other in terms of technology.
There are two primary types of metal 3D printing technology used in industry right now: powder bed melting and directional energy deposition. There are big distinctions between them in terms of their technological features and the situations in which they might be used:
1. The method for melting powder beds
Selective Laser Melting (SLM): It can cut titanium alloys, nickel-based alloys, and 17-4PH stainless steel with fibre lasers that use 1000 to 2000W of power and dynamic focusing mirrors to make a spot that is 0.05mm wide. Platinum Technology's dual laser collaboration technology has made printing 200% faster and cut the cost of making aviation engine fuel nozzles by 65% for each component.
Electron beam selective melting (EBSM) is a method that uses a 30kW electron beam to work in a vacuum and scan at a speed of 8m/s. It is best for working with metals with high melting points, such tantalum and tungsten. Siemens Energy employs this technology to make nuclear steam generator tube sheets. It cuts the number of welds from 127 to 3 and lowers the danger of leaks by 90%.
Directed energy deposition method Laser Near Nett Forming (LENS): A coaxial powder feeding system sends metal powder with a diameter of 45–106 μm into the laser focusing area to make gradient materials. Using this technology, Honeywell has made a Ti6Al4V/Inconel 718 bimetallic turbine disc that is three times more resistant to thermal fatigue.
Arc Additive Manufacturing (WAAM): This method uses a MIG/TIG welding arc as the heat source and can deposit up to 8 kg/h, making it good for making massive structural parts. The 3D printing technology for marine propulsion shafts made by CSIC 725 has cut material costs by 40% and sped up production by 70%.
Big steps forward in materials science
The material system for metal 3D printing is changing from standard alloys to functional and smart ones:
Development of high-performance alloys: Shagang Group has made the GTD222 nickel-based high-temperature alloy in response to demand in the aviation industry. It has a tensile strength of 1200MPa at 650 °C, which is 25% higher than the typical GH4169 material.
Multi-material composite technology: By changing the size of the powder particles (for example, 45 μm base powder and 15 μm refined powder), the grain size of titanium alloy can be reduced from 50 μm to 10 μm, giving it a fatigue life of more than 10 ⁷ cycles.
Using smart materials: To make an adaptive valve that can automatically change its opening between 40 and 80 °C, shape memory alloy particles are implanted in 316L stainless steel. The inaccuracy is kept to ± 0.5 °C.
Deep penetration into industrial-grade uses
Three high-end industrial areas have made a lot of use of metal 3D printing technology:
Aerospace: The Airbus A350XWB plane has 3D printed titanium alloy brackets that make the structure 30% lighter and the fuel efficiency 2% better. Rolls Royce's UltraFan engine project used 3D printing technology to cut the number of compressor blades from 36 to 18. This made the thrust-to-weight ratio 15% higher.
Energy tools: The fourth generation nuclear power high-temperature gas cooled reactor steam generator made by State Power Investment Corporation uses 3D printed nickel-based alloy heat transfer tubes. This makes the heat transfer efficiency 92%, which is 8 percentage points higher than traditional designs.
BMW Group has used 3D printed aluminium alloy battery trays in the iX3 electric vehicle model. This made the car 12 kg lighter and increased its NEDC range by 15 km.