A method and device for circulating and purifying impurity gas in a low positive pressure sealing molding room

Abstract

The invention discloses a method and a device for purifying impurity gas in a low positive pressure sealed molding chamber; the device comprises a molding chamber and a gas circulation purification system, and the gas circulation purification system is controlled by a computer; two ends of the molding chamber are respectively provided with gas circulation Outlet A and gas circulation inlet B; the gas circulation purification system includes a circulating gas circuit composed of a gas uniform distribution device, a filter box, an activated carbon filter box, a circulating air pump, a differential pressure sensor, etc.; the two pressure guide ports of the differential pressure sensor are respectively connected On the outlet pipeline of the filter box, on the inlet pipeline of the circulating air pump, and on the inlet pipeline of the gas distribution device; this device has higher purification efficiency, and can quickly adjust the oxygen content, air pressure and metal dust particle concentration in the molding chamber environment. Item index, the degree of purification of metal dust particles in the molding room environment is high.

Description

technical field [0001] The invention relates to the field of selective laser melting (Selective Laser Melting, SLM) additive manufacturing, in particular to a method and a device for 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, dense organization, high dimensional accuracy and good mechanical properties. 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 the SLM process. The key indicators are oxygen content, air pressure, and metal dust particle concentration. Among them, the oxygen content is directly related to the forming quality of the formed metal parts, and has a great influe...

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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