Method and device for impurity gas circulating purifying in low positive-pressure sealing forming room

Abstract

The invention discloses a method and a device for impurity gas circulating purifying in a low positive-pressure sealing forming room. The device comprises a forming room and a gas circulating purifying system thereof, wherein the gas circulating purifying system is controlled by a computer; both ends of an inner cavity of the forming cavity are respectively provided with a gas circulating outlet A and a gas circulating inlet B; the gas circulating purifying system comprises a gas uniform distribution device, a filter box, an activated carbon filter box, a circulating gas pump, differential pressure sensors and the like which form a circulating gas path; two pressure guide ports of each of the differential pressure sensors are respectively connected with an outlet pipeline of the filter box, an inlet pipeline of the circulating gas pump, and an inlet pipeline of the uniform gas distribution device. The device has the advantages that the purifying efficiency is higher, the multiple indexes such as oxygen content, air pressure and concentration of metal dust particle in the environment of the forming room,, can be quickly adjusted, and the purifying degree on metal dust particles in the environment of the forming room is high.

Description

technical field [0001] The invention relates to the field of selective laser melting (Selective Laser Melting, SLM) additive manufacturing, and in particular to a method and device for circulating and purifying impurity gas in a low positive pressure sealing molding chamber. Background technique [0002] With the development of Selective Laser Melting (SLM) technology, SLM has been able to directly manufacture metal parts with metallurgical bonding, compact structure, high dimensional accuracy and good mechanical properties, which can be formed in small batches, personalized, with complex surfaces and Metal parts with internal structures have broad application prospects and become a research hotspot in the field of additive manufacturing today. [0003] It is very important to control the gas environment in the sealing molding room during SLM processing, and the key indicators are oxygen content, air pressure, and metal dust particle concentration. Among them, the oxygen co...

AI Technical Summary

Problems solved by technology

Usually, the particle size of metal materials used in SLM, such as 316L stainless steel, CoCrMo alloy and titanium alloy, is only tens of microns, and the size of the metal spatter generated during the SLM forming process is smaller. In the air, it not only affects the performance of formed metal parts, but also seriously threatens the personal safety of operators

In addition, the existing gas filtering device applied to the SLM system still has some defects: the cleanliness of the gas obtained by the simple HEPA filter (high-efficiency air filter) is not high enough; the cleaning of the metal dust collected by the HEPA filter and the The collection process is not convenient enough, and there is still much room for improvement; due to factors such as the air intake method, the filter screen is partially blocked and worn, and its working life is relatively short; the sealing performance of the existing gas circulation purification device is not good enough, and its The metal dust in the internal working space will be disturbed by the external air flow and spread to the molding cavity of the SLM equipment or the external air, which will affect the SLM processing process and human health, etc.

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