Pore defect removing method for metal additive manufacturing component based on online monitoring

Abstract

The invention discloses a pore defect removing method for a metal additive manufacturing component based on online monitoring. A DED metal additive manufacturing system, an on-line monitoring system for monitoring pore defect positions in real time in the additive manufacturing process, a laser shock peening system for repairing defects, and a central control system used for coordinating and matching the additive manufacturing process, the online monitoring process and the laser shock peening process are included. The central control system obtains a pore distribution model according to the on-line monitoring system; the laser shock peening system is controlled to conduct interlayer 3D shock peening on the additive manufacturing sample through high-energy pulse laser, for air hole defects,thin-layer metal above the defects is broken, and then feeding in the follow-up forming process is controlled through the DED metal additive manufacturing system to eliminate the air hole defects; and for cracks in the length direction parallel to the manufacturing direction, the central control system enables the cracks to be closed by applying residual pressure stress, and the cracks can be removed after defects are detected.

Description

technical field [0001] The invention relates to the technical field of additive manufacturing, in particular to a method for removing pore defects of metal additive manufacturing components based on online monitoring. Background technique [0002] Directed Energy Deposition (DED) is an important branch in the field of metal additive manufacturing. Porosity and cracks are the most common defects inside it. First, these pores will produce microcracks, resulting in low mechanical strength; second. , due to the distribution of pores of different sizes and shapes throughout the space, it will also reduce the fatigue life of the entire component. At present, to control the internal pores in experiments and production practices, methods such as optimizing process parameters, selecting higher-quality raw materials or shielding gases are generally adopted, but even so, the internal pores of components cannot be completely eliminated. In order to discover the internal pores in real t...

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Problems solved by technology

This repair method still does not deviate from the traditional method of repairing defects of formed components by modifying the manufacturing process parameters, its repair ability is relatively limited, and some internal defects that have formed cannot be repaired

[0004] In the Chinese patent (the announcement number is CN 108931535 A), a method for online monitoring of pore defects in laser additive manufacturing is given, and the laser additive manufacturing On-line monitoring of stomatal defects, but it is limited to on-line monitoring, and cannot make up for the detected defects after monitoring

[0005] In the Chinese patent (the authorized announcement number is CN 105248011 B), a method of laser shock forging and laser cutting composite additive manufacturing device is given. The energy source laser originally used for laser additive manufacturing is divided into three parts. They are respectively used for laser additive manufacturing, laser impact forging and laser cutting, but the laser used for laser additive manufacturing is a continuous laser with low power, and cannot form an effective impact strengthening effect on the workpiece after splitting

[0006] In the Chinese patent (the authorized announcement number is CN 107378250 B), a kind of laser cladding impact forging composite molding method based on CCD monitoring for large-scale parts is given. Effective detection, it will waste a lot of time and energy to perform laser shock forging on the entire large-sized parts; in addition, the beneficial effect of laser shock forging is weaker than that of laser shock strengthening, and may not be able to effectively affect its internal pore defects ; and this method is only for laser cladding molding, which has great limitations

In this way, the repair process not only consumes a lot of time and energy, but also the vibration and waste generated during the cutting process will also have a negative impact on the manufacturing process.

From the above existing technologies, it can be seen that some progress has been made in the monitoring of the internal pores of additively manufactured components, but the repair of internal pore defects still remains at the adjustment of manufacturing parameters and materials. Methods for removing defects after they have been detected

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