A method of bilateral mobile heat source collaborative additive manufacturing

Abstract

A kind of bilateral mobile heat source collaborative additive manufacturing method, it is characterized by: in the process of component layer additive, mobile heat source is applied to the upper and lower sides of the material manufactured respectively, one side mobile heat source moves along with additive path and heats the surface layer material and the material being added, another mobile heat source is applied to heat the other side of the material manufactured, the other mobile heat source moves independently with the aforementioned mobile heat source on the two sides of the material manufactured, and the range of action, power density and other parameters of the two mobile heat sources are cooperatively controlled to realize collaborative additive manufacturing.The present application breaks through the principle limitation of traditional single-side heat source additive manufacturing method, forms a temperature field along the center plane in a "mirror image" distribution on both sides of the component, ensures that the material always maintains stress balance during the manufacturing process, thereby greatly reduces the stress in the thickness direction, significantly inhibits the deformation of the component, and realizes high-quality and high-precision additive manufacturing.

Description

Technical Field

[0001] This invention relates to additive manufacturing technology, and more particularly to an additive manufacturing technology with coordinated heat sources, specifically an additive manufacturing method with coordinated dual-sided moving heat sources. Background Technology

[0002] Additive manufacturing technology has demonstrated significant value and broad application prospects in strategic emerging industries such as aerospace, rail transportation, new energy, new materials, and medical instruments.

[0003] However, existing additive manufacturing technologies generally employ a single-sided moving heat source to heat the material being deposited. Under the influence of this single-sided moving heat source, the material repeatedly undergoes asynchronous, extreme high temperatures and rapid cooling. The drastic and uneven physical and chemical changes lead to a continuous accumulation of large and uneven thermal and phase transformation stresses along the material's thickness direction. This causes significant deformation of the component during the additive manufacturing process, and in severe cases, the component may even detach from the panel, making manufacturing impossible. Furthermore, when the internal stress of the component exceeds the material's ultimate strength, the component will face serious manufacturing defects such as cracking and structural failure. Therefore, the existing single-sided moving heat source heating method inherently generates large and uneven stresses, resulting in large component deformations and numerous defects, severely restricting the high-quality, high-precision additive manufacturing of advanced equipment in fields such as aerospace.

[0004] Temperature field control is a crucial method for managing stress and deformation in additive manufacturing. Domestic and international businesses and academia have conducted extensive scientific research and technological development on temperature field control during additive manufacturing. 1) Support structure and path optimization: Patents such as CN202310282050.2 and CN202211361480.5 propose joint optimization of the single-sided moving heat source path and support structure in additive manufacturing based on prediction results to control residual stress and deformation. However, this method still uses a single-sided moving heat source, making it difficult to avoid large and uneven residual stress in the thickness direction. 2) Increasing manufacturing environment temperature: Patents such as CN202010992847.8 propose placing the additive manufacturing device in a high-temperature environment to achieve uniform preheating and slow cooling of the entire component, reducing forming thermal stress during additive manufacturing and effectively suppressing material cracking. 3) Substrate heating: Patents such as CN202010217603.2 propose heating the substrate used for additive manufacturing to reduce the temperature gradient in the thickness direction of the component, thereby reducing the level of residual stress. The above method introduces an overall heat source in addition to the single-sided moving heat source. However, due to the constraints of material conformability and adhesion to the substrate, the overall heat source cannot heat the material to its melting temperature. The overall heat source heating temperature is inevitably much lower than the temperature of the single-sided moving heat source, and there is still a temperature gradient in the thickness direction of the component. Consequently, it is still difficult to avoid large and uneven residual stress.

[0005] CN202311438122.4 proposes reducing the warpage of the substrate by adding a moving heat source to the back of the substrate, thereby reducing the impact of substrate deformation on the component. This method only considers the temperature field balance on both sides of the substrate. While this helps the substrate maintain shape stability during additive manufacturing, the temperature on the substrate is lower than that of the component. Therefore, even with the application of a moving heat source on the back of the substrate, it is difficult to completely eliminate the temperature gradient along the thickness direction of the component, and thus, it is still difficult to avoid large and uneven residual stress in the component. In summary, existing methods struggle to control large and uneven residual stress in components, making it difficult to achieve high-quality, high-precision additive manufacturing of high-end equipment in fields such as aerospace. Summary of the Invention

[0006] The purpose of this invention is to address the problem of large and uneven residual stress caused by the repeated asynchronous extreme high temperatures and rapid cooling of components in existing single-sided heat source additive manufacturing processes. This invention proposes a dual-sided moving heat source synergistic additive manufacturing method. Moving heat sources are applied to the upper and lower sides of the deposited material, and by synergistically controlling parameters such as the effective range and power density of the dual-sided moving heat sources, a temperature field distributed in a "mirror image" along the center plane of the component is formed. This ensures that the material maintains stress balance throughout the repeated heating, melting, cooling, and phase transformation processes, thereby significantly reducing thermal and phase transformation stress in the thickness direction, thus significantly suppressing component deformation and achieving high-quality, high-precision additive manufacturing.

[0007] The technical solution of this invention is as follows:

[0008] A method for additive manufacturing with dual-sided moving heat sources is characterized in that, during the layer-by-layer additive manufacturing process of a component, moving heat sources are applied to the upper and lower sides of the manufactured material respectively. One side of the moving heat source moves along the additive path and heats the manufactured surface material and the material being added. The other side of the manufactured material is heated by the other moving heat source. The other moving heat source and the aforementioned moving heat source move independently on both sides of the manufactured material. The range of action, power density and other parameters of the dual-sided moving heat sources are coordinated and controlled to achieve collaborative additive manufacturing.

[0009] The mobile heat source is a heat source whose heating power acting on a certain area of ​​the material surface or interior changes in the range of its action in space.

[0010] The principle of applying the dual-sided moving heat source can be the principle of heat convection heating such as hot air, or the principle of heat radiation heating such as infrared irradiation or laser irradiation, or the principle of heat conduction heating such as hot nozzles, hot rollers, hot pressure heads, and hot molds, or the formation of internal heat sources in the material through contact or non-contact radio frequency, induction, or microwave energy feeding; a suitable heating method is selected according to the thermal boundary conditions and parameters on both sides of the material, such as ambient temperature, convection dissipation coefficient, mold specific heat capacity, and heat transfer coefficient, to ensure that the heat sources on both sides of the deposited material act directly on the surface or interior of the material.

[0011] The method for moving the dual-sided heat source on both sides of the material is implemented as follows: Δl1 is defined as the radius of curvature of the deposition point of the manufactured part material along the tangent direction of the additive trajectory; the intersection of the extension line of the deposition point along the thickness direction and the other side surface of the part is obtained; a reference line parallel to the tangent direction of the additive trajectory of the deposition point is drawn through this intersection point; Δl2 is the radius of curvature of the intersection point along the reference line; when Δl1 = Δl2, the heating power range of the dual-sided heat source is synchronized and forms a temperature field symmetrical along the center surface of the manufactured material; when Δl1 ≥ Δl2, the range of motion and power density of the moving heat source on the side with the arc length increment of Δl1 is greater than that on the side with the arc length increment of Δl2; when Δl1 ≤ Δl2, the range of motion and power density of the moving heat source on the side with the arc length increment of Δl1 is less than that on the side with the arc length increment of Δl2.

[0012] The beneficial effects of this invention are:

[0013] The significant advantages of this invention for composite material curing and molding lie in the fact that existing additive manufacturing methods using a single-sided moving heat source inevitably lead to a large temperature difference between the two sides of the part, resulting in large and uneven residual stress, ultimately causing difficulties in part manufacturing, low precision, and poor performance. This invention proposes a novel additive manufacturing method using dual-sided moving heat sources, creating a temperature field distributed in a "mirror image" along the central plane on both sides of the component. This ensures that the material maintains stress balance throughout the repeated heating, melting, cooling, and phase transformation processes, thereby significantly reducing thermal and phase transformation stresses in the thickness direction. This, in turn, significantly suppresses component deformation, achieving high-quality and high-precision additive manufacturing.

[0014] This invention overcomes the limitations of traditional single-sided moving heat source additive manufacturing methods by proposing a dual-sided moving heat source synergistic additive manufacturing method. Moving heat sources are applied to both the upper and lower sides of the deposited material. One moving heat source moves along the material deposition path and heats the material being deposited, while the other moving heat source heats the other side of the deposited material. This second moving heat source moves independently on both sides of the deposited material, and the synergistic control of parameters such as the effective range and power density of the dual moving heat sources achieves collaborative additive manufacturing. This method can create a temperature field with a mirror-image distribution along the central plane on both sides of the component during the layer-by-layer deposition process. This ensures that the material maintains stress balance during repeated heating, melting, cooling, and phase transformation, thereby significantly reducing thermal and phase transformation stress in the thickness direction and significantly suppressing component deformation, achieving high-quality and high-precision additive manufacturing. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the fused deposition modeling implementation case of dual-laser source collaboration in Example 1.

[0016] Figure 2This is a schematic diagram of a fused deposition additive manufacturing implementation case in Example 2, in which a laser source and an addressable heating film moving heat source work together.

[0017] Figure 3 This is a schematic diagram of the addressable heating film moving heat source structure in Example 2. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to illustrate certain specific implementations of this method and are not intended to limit the scope of protection of the present invention. Furthermore, any modifications and variations made by those skilled in the art based on the additive manufacturing method with coordinated bilateral moving heat sources in this invention after its disclosure are within the scope defined by the appended claims. Specific Implementation Example 1:

[0020] like Figure 1 The diagram shows a fused deposition modeling (FDM) additive manufacturing process with dual heat sources. The extruder 2 deposits material layer by layer on the tempered glass substrate 6 and continuously extrudes and deposits material 4 layer by layer onto the surface of the manufactured material 3. A laser source 1 is set up to move with the extruder 2. The laser source 1 and the extruder 2 are mounted by a servo system. The laser beam emitted by the laser source 1 irradiates the upper surface of the manufactured material 3 to form an upper moving heat source, and heats the surface layer of the manufactured material 3 and the material 4 being added.

[0021] A laser source 5 is set on the underside of the light-transmitting tempered glass substrate 6. The laser source 5 is also mounted on a servo system and emits a laser beam that passes through the tempered glass substrate 6 and reaches the underside of the manufactured material 3.

[0022] Define the arc length increments along the material additive path on the top and bottom sides of the manufactured material 3 as Δl1 and Δl2, respectively, as follows: Figure 1 The area being deposited is a flat plate, Δl1 = Δl2. The heating power ranges of laser sources 1 and 5 move synchronously to form a temperature field 7 symmetrical along the center plane of the manufactured material. When Δl1 > Δl2, the range and power density of the moving heat source on the side with the arc length increment of Δl1 are greater than those on the side with the arc length increment of Δl2. When Δl1 < Δl2, the range and power density of the moving heat source on the side with the arc length increment of Δl1 are less than those on the side with the arc length increment of Δl2. Specific Implementation Example 2:

[0024] like Figure 2The diagram shows a schematic of a fused deposition modeling (FDM) additive manufacturing implementation example where a laser source and an addressable heating film moving heat source work together. The extruder 2 deposits material layer by layer on an aluminum alloy substrate 9 and continuously extrudes and deposits material 4 layer by layer onto the surface of the manufactured material 3. A laser source 1 is set up to move with the extruder 2. The laser source 1 and the extruder 2 are mounted by a servo system. The laser beam emitted by the laser source 1 irradiates the upper surface of the manufactured material 3 to form an upper moving heat source and heats the surface layer of the manufactured material 3 and the material 4 being added.

[0025] like Figure 2 and Figure 3 As shown, an addressable heating film 8 is set between the aluminum alloy substrate 9 and the manufactured material 3. 10 is the smallest heating unit on the addressable heating film 8. The start-up and stop-heating of the smallest heating unit 10 can be controlled independently. By controlling the order of opening and closing of the smallest heating units 10 distributed in the control array, the lower moving heat source moves synchronously with the upper moving heat source.

[0026] Define the arc length increments along the material additive path on the top and bottom sides of the manufactured material 3 as Δl1 and Δl2, respectively, as follows: Figure 2 The area being deposited is a flat plate, Δl1 = Δl2. The heating power ranges of laser source 1 and laser source 5 move synchronously to form a temperature field symmetrical along the center plane of the manufactured material. When Δl1 > Δl2, the range and power density of the moving heat source on the side with the arc length increment of Δl1 are greater than those on the side with the arc length increment of Δl2. When Δl1 < Δl2, the range and power density of the moving heat source on the side with the arc length increment of Δl1 are less than those on the side with the arc length increment of Δl2.

[0027] The parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. A method for additive manufacturing with dual-sided moving heat sources, characterized in that: During the layer-by-layer additive manufacturing process, moving heat sources are applied to the upper and lower sides of the manufactured material. One moving heat source moves along the additive path and heats the manufactured surface material and the material being added. A second moving heat source is applied to heat the other side of the manufactured material. This second moving heat source moves along both sides of the manufactured material. The method of moving the two moving heat sources along both sides of the material is implemented as follows, defining Δ... l 1 Given the radius of curvature of the material deposition point along the tangent direction of the additive manufacturing trajectory, the intersection point of the extension line of the deposition point along the thickness direction and the other side surface of the part is obtained. A reference line parallel to the tangent direction of the additive manufacturing trajectory of the deposition point is drawn through this intersection point. Δ l 2 The radius of curvature of the intersection point along the reference line; When Δ l 1 = Δ l 2 At that time, the heating power of the two heat sources acts synchronously and forms a temperature field symmetrical along the center plane of the manufactured material. When Δ l 1 ≥Δ l 2 At that time, the arc length increment is Δ l 1 The effective range and power density of the moving heat source on one side are greater than the arc length increment Δ. l 2 A moving heat source on one side, when Δ l 1 ≤Δ l 2 At that time, the arc length increment is Δ l 1 The effective range and power density of the moving heat source on one side are less than the arc length increment Δ. l 2 A mobile heat source on one side.

2. The method according to claim 1, characterized in that... The mobile heat source is a heat source whose heating power acting on a certain area of ​​the material surface or interior changes in the spatial range.

3. The method according to claim 1, characterized in that... The dual-sided moving heat source is a hot air convection heat source; or an infrared irradiation or laser irradiation heat source; or a hot nozzle or hot roller; or a contact or non-contact radio frequency, induction or microwave energy feeding to form an internal heat source of the material.

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