Method for repairing defects of lap joint positions of adjacent sub-areas formed by selective laser melting

A technology of laser selective melting and lap joint position, which is applied in the field of additive manufacturing engineering to achieve the effect of eliminating molten pool defects

Inactive Publication Date: 2020-11-24
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a method for repairing the overlapping position defects of adjacent partitions in laser selective melting and forming, which can effectively remove the defects caused by excessive laser energy input at the overlapping of adjacent partitions during laser selective melting and forming. Melting through multilayer defective molten pools containing keyholes

Method used

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  • Method for repairing defects of lap joint positions of adjacent sub-areas formed by selective laser melting
  • Method for repairing defects of lap joint positions of adjacent sub-areas formed by selective laser melting
  • Method for repairing defects of lap joint positions of adjacent sub-areas formed by selective laser melting

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Example 1—Single-layer printing

[0024] (1) Use IN718 spherical powder, powder diameter 15-53um, fluidity 16s / 50g, D 50 32um, the substrate of laser selective melting equipment is preheated to 80°C for single-layer printing.

[0025] (2) The printing process is carried out in a protective atmosphere of Ar gas, and the oxygen content in the cabin is controlled below 200ppm.

[0026] (3) The parameters of laser selective melting are: laser power 195W, powder coating thickness 30um, substrate preheating temperature 80°C, scanning line spacing 70um, scanning strategy is laser bidirectional scanning, no strip overlap; scanning speed is 800mm / s, 900mm / s, 1000mm / s, 1100mm / s, 1200mm / s, 1300mm / s.

[0027] (4) Clean the substrate containing a single-layer printing layer with alcohol and place it under a microscope to observe the uniformity between the end of the melt channel and the inside of the melt, as shown in Figure 4 As shown, when the scanning speed is 800mm / s, 900m...

Embodiment 2

[0028] Example 2—Block Printing

[0029] (1) Using the materials and equipment used in Example 1, and the process parameters for single-layer printing, a 10x10x10mm IN718 block was printed.

[0030] (2) Slice the formed parts with a thickness of 30um, plan the scanning path of the components, adopt strip-type bidirectional laser scanning, and set the laser jump speed of adjacent melting channels to 3000mm / s.

[0031] (3) The parameters of laser selective melting are: laser power 195W, powder coating thickness 30um, substrate preheating temperature 80°C, scanning line spacing 70um, interlayer rotation 67°, laser scanning speed 1000mm / s.

[0032] (4) The printed IN718 test block was removed from the substrate by wire cutting, and after ultrasonic cleaning, the density of the block was determined to be 99.0% by the Archimedes drainage method. Use wire cutting to cut the over-dense block along the forming direction and perpendicular to the forming direction in turn, and conduct m...

Embodiment 3

[0034] Example 3—Block Printing

[0035] (1) Using the materials and equipment used in Example 1, and the process parameters for single-layer printing, a 10x10x10mm IN718 block was printed.

[0036] (2) Slice the formed parts with a thickness of 30um, plan the scanning path of the components, adopt strip-type bidirectional laser scanning, and set the laser jump speed of adjacent melting channels to 4000mm / s.

[0037] (3) The parameters of laser selective melting are: laser power 195W, powder coating thickness 30um, substrate preheating temperature 80°C, scanning line spacing 70um, interlayer rotation 67°, laser scanning speed 1000mm / s.

[0038] (4) The printed IN718 test block was removed from the substrate by wire cutting, and after ultrasonic cleaning, the density of the block was determined to be 99.4% by the Archimedes drainage method. Use wire cutting to cut the over-dense block along the forming direction and perpendicular to the forming direction in turn, and conduct m...

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Abstract

The invention discloses a method for repairing defects of lap joint positions of adjacent sub-areas formed by selective laser melting. According to the method, a laser scanning speed is adjusted, anda melting channel state that the tail end of a melting channel and the interior of the melting channel are uniform in morphology and no obvious hole is formed in the tail end of the melting channel isobtained; on the basis of forming uniform parameters of the morphology of the tail end of the melting channel and the interior of the melting channel, the laser jump speed between the adjacent melting channels is adjusted, and a defect molten pool with multiple layers of built-in keyholes fused through due to too high laser energy input at the lap joint of the adjacent sub-areas during selectivelaser melting forming is effectively removed; and the density of an IN718 test block can be improved from 98.3% to 99.4% only aiming at the defects at the lap joint positions of the sub-areas.

Description

technical field [0001] The invention belongs to the technical field of additive manufacturing engineering, and more specifically relates to the formation of defects at the overlapped positions of the zones during laser selective melting and forming and a proposed solution. Background technique [0002] As the most common technology in current metal 3D printing and forming, the selective laser melting (SLM) process has the characteristics of personalized manufacturing, high forming precision and good surface quality, and can manufacture parts with complex structures that are difficult to achieve by traditional processing methods. . It has been widely used in medical equipment, aerospace, orthopedic implants and other fields. The density, internal defects, residual stress and surface quality of the parts after SLM forming play a decisive role in the mechanical properties of the parts. How to improve the density of formed parts and reduce internal defects has become a hot spo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F3/105B33Y10/00B33Y50/02
CPCB33Y10/00B33Y50/02
Inventor 马宗青赵亚楠胡章平刘永长余黎明李冲刘晨曦
Owner TIANJIN UNIV
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