3D Printing Nitrided Surface Layer for Wear Resistance
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Solution Overview
Problem
Additive manufacturing technologies face challenges with low corrosion and wear resistance, particularly in using carbide materials due to cracking from fast laser heating and cooling, and difficulty in predicting or controlling high shrinkage rates during sintering, which hinders the application of binder jetting for sealing components with high dimensional accuracy.
Innovation Solution
A 3-D printing method involving alternating laser-scanning and treatment gas feeding to form local hardened layers, using ammonia as a treatment gas, which adjusts the internal elastic modulus and surface hardness, and controls the nitridation gradient to create a wear- and corrosion-resistant nitrided surface layer without additional surface treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbide material is used for sealing components to improve wear resistance and corrosion resistance, then material durability is improved, but cracks are easily caused by fast laser heating and cooling
Solution Approach 1:
The patent applies parameter changes by modifying the laser processing parameters (power, speed, pattern) and introducing treatment gas (ammonia or nitrogen) to control the heating and cooling rates during SLM. This resolves the contradiction by enabling the use of carbide materials without causing cracks, while achieving the desired wear and corrosion resistance through controlled nitridation or carbonitridation of the surface.
2Strength
If binder jetting technology is used to manufacture hard metal components to avoid cracking, then crack resistance is improved, but high shrinkage rate during sintering makes dimensional accuracy difficult to control
Solution Approach 1:
The patent applies preliminary action by performing surface treatment (nitridation or carbonitridation) during the SLM printing process itself, before final component removal from the build plate. This allows for controlled surface hardening and shrinkage compensation while the component is still constrained, improving dimensional accuracy compared to post-printing treatments.
3Reliability
If additional surface treatments are applied to achieve wear and corrosion resistance, then surface durability is improved, but power consumption and manufacturing costs increase
Solution Approach 1:
The patent merges the surface treatment process with the SLM manufacturing process by introducing treatment gas (ammonia or nitrogen) during or after laser scanning. This combines two separate processes (printing and surface treatment) into one, reducing power consumption and manufacturing costs while achieving the desired surface durability through in-situ nitridation or carbonitridation.
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
The method achieves a wear- and corrosion-resistant nitrided surface layer with an ideal lattice structure, maintaining ductility of the central area, reducing power consumption and costs, and precisely controlling the nitridation gradient to avoid overhardening, thus enhancing the dimensional accuracy and durability of components.
Implementation Method 1
laser-scan a printing material according to a 3-D printing model so that the printing material starts to be sintered into a printout in the preset shape layer by layer from the bottom up
Implementation Method 2
the printing material starts to be sintered into a printout
Implementation Method 3
feed a treatment gas into a 3-D printing device and laser-scan a local area of the printout so that the treatment gas reacts with the surface of the local area of the printout and a hardened layer is formed
Implementation Method 4
laser-scan a local area of the printout so that the treatment gas reacts with the surface
Data Source
AI summary
A 3-D printing method and a 3-D printout are provided. In an embodiment, the 3-D printing method includes laser-scanning a printing material according to a 3-D printing model so that the printing material starts to be sintered into a printout in a shape, layer by layer from the bottom up; and feeding a treatment gas into a 3-D printing device and laser-scan a local area of the printout so that the treatment gas reacts with the surface of the local area of the printout and a hardened layer is formed. The laser scanning and the feeding of the treatment gas are performed alternately until a printout with local hardened layers is formed. By adjusting the gas environment, the components can be manufactured by selective laser melting equipment to have a wear- and corrosion-resistant nitrided surface layer and keep the expected ductility of the central area.