Laser Metal Deposition with Particle Preheating for Low Heat Input
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Solution Overview
Problem
Current laser metal deposition processes are limited by high heat input and significant blending of materials at the component surface, restricting processing speeds and affecting mechanical properties.
Innovation Solution
A laser metal deposition process where filler material particles are preheated to boiling point before reaching the component surface, increasing their velocity and reducing heat input, allowing for higher processing speeds with minimal material blending through optimized beam-particle interaction and process parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser beam directly melts powder particles in the melt pool on the component surface, then the filler material is metallurgically bonded to the component, but the processing speed is limited to 0.2-5 m/min due to high heat input and long melting time
Solution Approach 1:
The patent applies preliminary action by pre-heating the powder particles to their melting point in a first interaction zone before they reach the component surface. This pre-heating reduces the energy required during actual deposition and enables higher processing speeds. The particles are prepared in advance (heated to melting point) so that when they reach the melt pool, they require minimal additional energy to melt and bond, thus resolving the contradiction between speed and heat input.
Solution Approach 2:
The patent segments the laser beam interaction into two distinct zones: a first interaction zone where particles are pre-heated to melting point, and a second interaction zone (melt pool) where metallurgical bonding occurs. This segmentation allows the heating function and bonding function to be separated in space, enabling high-speed processing while controlling heat input to the component.
2Strength
If the laser beam irradiates the component surface for an extended period to ensure complete melting and bonding, then strong metallurgical bonds are formed, but significant blending of materials occurs and mechanical properties deteriorate
Solution Approach 1:
By pre-heating particles to their melting point before they reach the component surface, the patent eliminates the need for extended laser irradiation time at the component surface. The particles arrive already melted or near-melted, requiring only brief contact with the melt pool to form bonds. This preliminary preparation resolves the contradiction by enabling strong bonding without prolonged exposure that causes harmful material blending.
Solution Approach 2:
The patent implements the skipping principle by rapidly transporting pre-heated particles through the laser field and onto the component surface at high speeds (0.2-5 m/min processing speed improvement). The particles 'skip' through the interaction zone quickly, minimizing the time for harmful blending to occur while still achieving complete melting and bonding. This rapid passage reduces the duration of harmful thermal effects.
3Productivity
If the process speed is increased to reduce production time, then productivity improves, but heat input increases and material blending worsens
Solution Approach 1:
The patent applies preliminary action by performing the energy-intensive heating of powder particles in a controlled first interaction zone before particles reach the component. This pre-heating to melting point reduces the energy that would otherwise be lost to prolonged irradiation at high speeds. The particles are prepared in advance with the exact energy needed, minimizing wasteful heat input when processing at elevated feed rates.
Solution Approach 2:
The patent changes the thermal state parameter of the filler material from ambient temperature to melting point temperature before deposition. This parameter change (pre-heating) fundamentally alters the energy balance of the process, enabling higher feed rates without proportional increases in heat input. The particles arrive in a high-energy state that reduces the total energy required for bonding.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables high-speed laser metal deposition with low heat input and minimal material blending, maintaining the mechanical properties of the component surface and achieving improved metallurgical bonds.
Implementation Method 1
the particles absorb optical energy from the laser beam in a beam-particle interaction zone
Implementation Method 2
at least a proportion of the particles reach boiling point along their trajectory through the laser beam and, as a result of vapor pressure, the velocity of at least the proportion of the particles in the direction of the surface of the component is increased
Implementation Method 3
a melt pool (4) generated by a laser beam (6) on a surface of a component
Implementation Method 4
the heating of the surrounding melt pool
Implementation Method 5
produce a metallurgical bond between an at least partially molten filler material and a surface of a component
Data Source
AI summary
A laser metal deposition process is disclosed for carrying out laser metal deposition, whereby the component is metallurgically bonded to partially molten filler material by means of a laser beam directed onto a surface of a component, whereby the filler material is delivered into the laser beam as a powder jet of particles, whereby the particles absorb optical energy from the laser beam in a beam-particle interaction zone at a distance (A) from the surface of the component as a function of process parameters (P) of the laser metal deposition process and of the grain fraction and material properties of the particles and are applied to the surface of the component, whereby the process parameters (P) are adjusted such that at least a proportion of the particles reach the boiling temperature (S) along their trajectory through the laser radiation.