Gas phase diffusion/ reaction laser metal 3D printing system and method

A 3D printing and laser technology, applied in the field of additive manufacturing, can solve problems such as limitations, prolonging product forming time, and reducing production efficiency, and achieve the effects of avoiding pollution, easier control of gas input, and improving work efficiency

Inactive Publication Date: 2016-02-17

HUAZHONG UNIV OF SCI & TECH

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AI-Extracted Technical Summary

Problems solved by technology

This technology generally modifies the surface of the entire workpiece, and some parts only need to be modified by chemical heat treatment in some areas, which limits the application of this technology

For 3D printed par...

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Method used

[0041] Referring to Figures 3 to 5, this part is a mold with complex cooling water channels, which cannot be manufactured by traditional machining methods, and is especially suitable for laser 3D printing. This mold requires high surface hardness and wear resistance. Traditional mold steel materials are prone to defects such as thermal stress and cr...

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Abstract

The invention discloses a gas phase diffusion/reaction laser metal 3D printing system. The gas phase diffusion/reaction laser metal 3D printing system comprises a laser selective melting forming device, and further comprises a ventilation device. The ventilation device comprises a gas storage tank, a gas pipe and a nozzle. The gas pipe is installed on the gas storage tank. The nozzle is fixedly installed on a laser head of the laser selective melting forming device. A vertically-through laser through hole is formed in the nozzle so that laser beams transmitted by the laser head penetrate the nozzle from the laser through hole. A vertically-through vent hole is further formed in the nozzle so that gas flowing in the gas pipe can penetrate the nozzle from the vent hole, and therefore the gas can be sprayed to the portion, needing chemical thermal treatment, on a part. According to the gas phase diffusion/reaction laser metal 3D printing system, the part of a complex structure can be manufactured, modification of any region in the part can be achieved, for example, nitridation/carbon enhancement and oxide dispersion enhancement, and the performance design of the part can be achieved while the structure complexity is achieved.

Application Domain

Additive manufacturing apparatusIncreasing energy efficiency

Technology Topic

EngineeringOxide +9

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Examples

Experimental program(1)

Example Embodiment

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Reference figure 1 , figure 2 , A gas phase diffusion/reaction laser metal 3D printing system, including selective laser melting forming equipment 1, and also including aeration equipment 2, wherein,

[0026] The ventilation device 2 includes a gas storage tank 21, a gas pipe 20, and a spray head 23. The gas pipe 20 is installed on the gas storage tank 21, and the spray head 23 is fixedly installed on the laser head 11 of the laser selection melting forming device 1. And the nozzle 23 is provided with a laser through hole 231 that penetrates up and down, so that the laser beam 12 emitted by the laser head 11 passes through the nozzle 23 from the laser through hole 231; in addition, the nozzle 23 is also provided with a vent hole 232 that penetrates up and down, so that the gas flowing in the air pipe 20 passes through the spray head 23 from the vent hole 232, so that the gas is sprayed to the part that needs chemical heat treatment.

[0027] Preferably, the number of the air storage tanks 21 is multiple, and the number of the air pipes 20 and the vent holes 232 is also set to multiple accordingly. Each air storage tank 21 is connected to a vent hole 232 through a air pipe 20, and each The gas types in each gas storage tank 21 are different, and each gas pipe 20 is equipped with a flow valve 22 to control the gas flow through the nozzle 23.

[0028] Preferably, a protective mirror 3 is provided at the laser through hole 231 to effectively prevent flying debris from passing through the laser through hole 231 and damage the laser head 11.

[0029] According to another aspect of the present invention, there is also provided a method for 3D printing using the 3D printing system, including the following steps:

[0030] 1) Establish a three-dimensional model of the part on the computer, and then convert the three-dimensional model of the part into an STL format file and import it into the selective laser melting forming equipment;

[0031] 2) Determine the modification information of the part according to the service conditions of the part, integrate the modification information and the three-dimensional shape information of the part, and then slice the three-dimensional model of the part and plan the processing path of each layer, including the processing path of each layer Including the movement path of the laser head 11 and the ventilation information in the nozzle 23, and then input these information data into the computer; wherein the modification information includes the modified part of the part and the performance requirements of the modified part, and the ventilation information includes the gas in the nozzle 23 The opening and closing, flow and type;

[0032] 3) Perform 3D printing according to the processing path planned in step 2) to complete the forming of the part.

[0033] Reference figure 2 , The 3D printing system of the present invention can realize the synchronous movement of the nozzle 23 and the laser head 11. When processing the parts that need to be modified, open the gas tank 21 switch, and adjust the flow valve 22 to input an appropriate amount of gas G, high-energy laser The beam 12 melts the powder layer M to form as figure 2 As shown in the tiny molten pool 4, under the action of the high temperature of the molten pool 4, the introduced gas G will react with the liquid metal M M+G→MG, and the generated MG is distributed in the matrix of the metal M, which can realize the designated area Metal modification; when processing parts that do not need modification, turn off the gas tank switch, stop inputting gas G, and complete the processing of this layer under the sole action of the laser beam 12.

[0034] Compared with the existing laser 3D printing technology, this method can not only manufacture parts with complex structures, but also realize the modification of any area in the parts, including nitriding/carburizing enhancement, oxide dispersion enhancement, etc., in the realization of complex structure At the same time, the performance design of parts can be realized.

[0035] Compared with traditional laser 3D printing technology, the present invention innovatively proposes a laser 3D printing method based on gas phase diffusion/reaction of controllable gas and metal powder, which can realize online modification of different parts of various metal parts and integrated forming of complex structures. Specific features are:

[0036] 1) During the laser 3D printing process, plan the movement path of the ventilation device 2 according to the information of the required modified part. The nozzle 23 and the laser head 11 move synchronously, and the required gas is injected according to the set amount to realize the required modified part The gas phase diffusion/reaction. For parts that do not need to be modified, the laser head 11 moves, but no gas is introduced into the nozzle 23 to realize processing.

[0037] 2) The method adopts the principle of layered manufacturing. According to the three-dimensional shape information of the part and the position information to be modified, the layered slice is performed and the processing path of each layer is planned. The processing path of each layer includes the movement path information of the laser head 11 and the nozzle Ventilation information within 23. The ventilation information includes air flow rate and gas type.

[0038] 3) The ventilation device 2 has multiple gas paths, and each gas path has an independently controlled flow valve 22 with the function of regulating the flow.

[0039] 4) The gas passed into the nozzle 23 can be N 2 , CO, CH 4 , CO 2 , O 2 One or more mixtures of, but not limited to the above types of gases.

[0040] 5) The entire laser 3D printing process is carried out in a vacuum chamber with a vacuum degree of 10 -2 Pa below.

[0041] Reference Figure 3 ~ Figure 5 , This part is a mold with a complicated cooling channel, which cannot be manufactured by traditional machining methods, and is especially suitable for laser 3D printing. This mold requires high surface hardness and wear resistance. Traditional mold steel materials are prone to defects such as thermal stress and cracks during 3D printing, which affect the service life. Therefore, the molded 316L stainless steel is used for manufacturing, and the gas phase diffusion method is used for surface hardening to obtain parts that are hard outside and tough inside. The processing and manufacturing cycle is short and the cost is low.

[0042] First, obtain the mold surface and runner surface information to establish a hardened area with a thickness of 1-2mm, Figure 4 with Figure 5 The middle section line is the hardened area, and this information is integrated with the three-dimensional structure information of the part. Slice through software, Figure 4 with Figure 5 Respectively image 3 Slice images of different cross-sections of the mold parts, obtain the movement path and ventilation information data of the nozzle 23 and the laser head 11, and input these information data into the computer.

[0043] Then, start the laser 3D printing equipment, gas source and gas path device. According to the slice information, the laser head 11 and the nozzle 23 move synchronously, and according to the ventilation information, a certain amount of N is injected into the position where ventilation is required. 2 , That is, when processing the section line of the slicing section, pass in gas and complete the processing of this part under the action of the laser and gas; when processing the blank part position, there is no need to ventilate and close the gas path to complete the processing of the entire section.

[0044] Finally, a new layer of powder M is laid on the formed plane, and then the next layer is processed until the entire three-dimensional part is manufactured.

[0045] Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present invention, All should be included in the protection scope of the present invention.

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Description & Claims & Application Information

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the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

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Classification and recommendation of technical efficacy words

Avoid pollution

Gas phase diffusion/ reaction laser metal 3D printing system and method

A 3D printing and laser technology, applied in the field of additive manufacturing, can solve problems such as limitations, prolonging product forming time, and reducing production efficiency, and achieve the effects of avoiding pollution, easier control of gas input, and improving work efficiency

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

Image

Examples

Example Embodiment

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Description & Claims & Application Information

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