Method for improving binding force of friction stir additive manufacturing structure layer

Abstract

The invention relates to a method for improving the binding force of a friction stir additive manufacturing structure layer. The method comprises the steps that oxide skin on the surfaces of a raw material bar and an additive substrate is removed; the additive substrate with the oxide skin removed is fixed; feeding the raw material bar towards the additive substrate; the raw material bar with the oxide skin removed makes contact with the additive base plate in the rotating advancing process and rubs against the additive base plate, and the end of the raw material bar is heated to be softened and evenly smeared on the surface of the additive base plate with the oxide skin removed; and after the raw material bar advances to the designated position, the raw material bar is controlled to be lifted by the height of one layer, the raw material bar is fed, and next-layer additive machining continues to be conducted on the additive base plate. According to the method, the problem of additive flowing caused by interlayer oxide inclusion of materials in the additive manufacturing process is solved, in addition, the metallurgical bonding effect between layers of the stirring friction additive manufacturing component is improved by removing oxide skin on the additive raw materials and the base plate, the longitudinal strength of the component is improved, and the service life of the component is prolonged. And the problem of longitudinal brittle fracture of the component caused by oxide inclusion is solved.

Description

Technical Field

[0001] The present invention relates to the field of additive technology, and in particular to a method for improving the interlayer bonding strength of a friction stir additive manufacturing tissue. Background Art

[0002] Friction stir additive manufacturing relies on the heat generated by the friction between the end face of the consumable rod and the substrate (or the previous coating) to soften the tip of the consumable rod and form a plastic deformation flow. The hollow stirring tool shoulder and the stirring needle will have a secondary effect on the coating, so that the coating and the lower material form a metallurgical bond. Friction stir additive manufacturing (FSAM) technology is a solid phase non-melting additive manufacturing method. FSAM technology is based on the principle of friction stir welding. Through the friction heat generated by the stirring head and the plastic deformation work, the additive material and the substrate are fused, and the manufacturing of three-dimensional complex shape components is converted into a simple two-dimensional plane shape layer by layer reciprocating superposition, and finally additive manufacturing is realized. Since the consumable rods and additive substrates used in additive manufacturing are existing extruded rods and profiles, the surface of the rods and additive substrates will have an oxide layer due to oxidation. During the friction stir solid phase additive manufacturing process, the material is always in a semi-solid state that does not exceed the melting point. Therefore, the oxide layer on the surface of the rod and the additive substrate will be deposited between the layers of the additive body (interlayer) during the additive process, and this oxide inclusion will affect the metallurgical bonding effect between the component layers, reduce the longitudinal bonding strength of the component, and in severe cases will cause brittle fracture of the component along the longitudinal direction. Not only that, the oxide scale on the rod and the substrate will also affect additive molding. During rapid additive, due to insufficient oxide scale breakage, a non-wetting layer will be formed between the additive body layers, affecting the metallurgical bonding between the materials, and in severe cases, it will cause the material to flow during the additive process.

[0003] When the existing friction stir additive method is used to manufacture components, the oxide scale on the additive raw material rod will affect the forming effect of the additive component and reduce the metallurgical bonding between the next layer of additive body and the previous layer; not only that, the oxide scale on the additive raw material will be deposited between the upper and lower additive layers to form oxide inclusions, which will significantly reduce the longitudinal strength of the additive component. The weak bonding force between the layers becomes the short board in the mechanical properties of the entire component, and becomes the first part to fail when the component is subjected to load. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for improving the interlayer bonding strength of stir friction additive manufacturing organizations, which can not only improve the molding effect of additive components, but also avoid the problem of interlayer oxidation inclusions caused by oxide scale affecting the performance of components.

[0005] In order to solve the above technical problems, the present invention provides a method for improving the bonding strength of the tissue layer in stir friction additive manufacturing, and the specific method is as follows:

[0006] S1. Remove the oxide scale on the raw material bar, the thickness of the oxide scale removed is in the range of 0.02-0.1mm;

[0007] S2. Remove the oxide scale on the surface of the additive substrate, the thickness of the oxide scale removed is in the range of 0.02-0.1mm;

[0008] S3. Fixing the additive substrate from which the oxide skin has been removed;

[0009] S4. The raw material bar from which oxidation and peeling has been removed is arranged above the additive substrate, and the raw material bar is placed in a vertical state, and the raw material bar is fed toward the additive substrate and controlled to rotate, so that the raw material bar is always in contact with the additive substrate and can rotate and move forward on the additive substrate along a certain trajectory;

[0010] S5. The raw material bar from which the oxide scale is removed contacts and rubs against the additive substrate during the process of rotating forward, and the end of the raw material bar is softened by heat to form a flowing state, and the material in the flowing state is evenly coated on the surface of the additive substrate from which the oxide scale is removed;

[0011] S6. When the raw material bar advances to the specified position, the raw material bar is controlled to be lifted up one layer, and the raw material bar is fed during the lifting process. After the raw material bar completes the lifting action, the additive substrate continues to be processed by the next layer of additive.

[0012] In one embodiment of the present invention, the raw material bar is aluminum, magnesium, copper or one of other metal materials and metal-based composite materials.

[0013] In one embodiment of the present invention, in step S3, the additive substrate from which the oxide scale has been removed is fixed by a positioning fixture of the friction stir additive equipment.

[0014] In one embodiment of the present invention, in step S4, the raw material bar is mounted on the spindle of the friction stir additive device through the additive tool, the friction stir additive device is used to control the additive tool and the raw material bar to move to a specified position, and the raw material bar is fed toward the additive substrate in the vertical direction through the feeding device of the friction stir additive device; when the raw material bar contacts the additive substrate, the spindle controls the additive tool to rotate, so that the raw material bar and the additive tool generate friction with the additive substrate at the same time.

[0015] In one embodiment of the present invention, the additive tool is a hollow cylindrical rotating body, which is used to fix the raw material bar from which the oxide scale is removed. The rotating body is connected to the main shaft of the stir friction additive equipment. The stir friction additive equipment provides rotational power through the main shaft, and controls the rotation of the rotating body by the main shaft to realize the rotation of the raw material bar. After the raw material bar is fixed in the rotating body, the end face of the rotating body remains flush with the end face of the raw material bar. When the rotating body rotates, the friction with the additive substrate generates heat to provide a heat source for the raw material bar, which is used to accelerate the softening speed of the end of the raw material bar.

[0016] In one embodiment of the present invention, the friction stir additive device controls the rotation speed of the additive tool to 300 r / min to 1000 r / min.

[0017] In one embodiment of the present invention, the friction stir additive device controls the advancement speed of the additive tool to 10 mm / min to 2000 mm / min.

[0018] In one embodiment of the present invention, the layer height of a single layer of additive manufacturing in step S6 is 0.5 mm to 3 mm.

[0019] In one embodiment of the present invention, in step S1, the oxide scale on the raw material bar with oxide scale is removed by using an external cylindrical polishing machine.

[0020] In one embodiment of the present invention, in step S2, a metal wire drawing machine is used to remove oxide scale from the surface of the additive manufacturing substrate with oxide scale.

[0021] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0022] The method for improving the interlayer bonding strength of a stir friction additive manufacturing organization described in the present invention improves the forming performance of the material in the stir friction additive manufacturing process by removing the oxide scale on the additive raw material and the substrate, and solves the problem of additive flow caused by oxide inclusions between layers of the material during the additive process; in addition, by removing the oxide scale on the additive raw material and the substrate, the metallurgical bonding effect between the layers of the stir friction additive manufacturing component is improved, the longitudinal strength of the component is improved, and the problem of longitudinal brittle fracture of the component caused by oxide inclusions is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0024] Figure 1 A flow chart of a method for improving the interlayer bonding strength of a friction stir additive manufacturing tissue in a preferred embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the additive manufacturing process in the present invention;

[0026] Figure 3 This is a cross-sectional rendering of the additively manufactured structure without removing the oxide scale;

[0027] Figure 4 This is a cross-sectional view of the additively manufactured structure after the oxide scale is removed;

[0028] Figure 5 It is a comparison chart of tensile properties data of additive manufacturing tissue without removing oxide scale and additive manufacturing tissue after removing oxide scale in the present invention;

[0029] Explanation of the reference numerals in the drawings in the specification: 1. Raw material bar; 2. Additive substrate; 3. Additive tool; 4. Spindle; 5. Feeding device. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0031] Reference Figure 1 As shown, the method for improving the bonding strength of the tissue layer in stir friction additive manufacturing described in the present invention is specifically as follows:

[0032] S1. Removing the oxide scale on the raw material bar 1;

[0033] S2. removing the oxide scale on the surface of the additive substrate 2;

[0034] S3. Fixing the additive substrate 2 from which the oxide skin has been removed;

[0035] S4. The raw material bar 1 after oxidation and peeling is placed above the additive substrate 2, and the raw material bar 1 is placed in a vertical state, and the raw material bar 1 is fed toward the additive substrate 2 and controlled to rotate, so that the raw material bar 1 always keeps in contact with the additive substrate 2 and can rotate and move forward on the additive substrate 2 along a certain trajectory;

[0036] S5. The raw material bar 1 from which the oxide scale has been removed contacts and rubs against the additive substrate 2 during the process of rotating forward, and the end of the raw material bar 1 is softened by heat to form a flowing state, and the material in the flowing state is evenly coated on the surface of the additive substrate 2 from which the oxide scale has been removed;

[0037] S6. When the raw material bar 1 moves to the designated position, the raw material bar 1 is controlled to be lifted up by one layer, and the raw material bar is fed during the lifting process, and after the raw material bar 1 completes the lifting action, the additive substrate 2 is continued to be processed with the next layer of additive. The layer height of a single layer of additive is 0.5 mm to 3 mm.

[0038] In this embodiment, the raw material bar 1 is aluminum, magnesium, copper or one of other metal materials and metal-based composite materials.

[0039] like Figure 2 As shown, in step S4, the raw material bar is installed on the spindle 4 of the stir friction additive device through the additive tool 3, the stir friction additive device is used to control the additive tool 3 and the raw material bar 1 to move to the specified position, and the feeding device 5 of the stir friction additive device is used to control the raw material bar 1 to be fed toward the additive substrate 2 in the vertical direction. When the raw material bar 1 contacts the additive substrate 2, the spindle 4 controls the additive tool 3 to rotate, so that the raw material bar 1 and the additive tool 3 generate friction with the additive substrate 2 at the same time.

[0040] In this embodiment, the additive tool 3 is a hollow cylindrical rotating body, which is used to fix the raw material bar 1 from which the oxide scale has been removed. The rotating body is connected to the main shaft 4 of the stir friction additive device. The stir friction additive device provides rotational power through the main shaft 4 to control the rotation of the rotating body to realize the rotation of the raw material bar 1; after the raw material bar 1 is fixed in the rotating body, the end face of the rotating body remains flush with the end face of the raw material bar 1, and when the rotating body rotates, the friction with the additive substrate 2 generates heat to provide a heat source for the raw material bar 1, which is used to accelerate the softening speed of the end of the raw material bar 1.

[0041] Preferably, the friction stir additive equipment controls the rotation speed of the additive tool 3 to 300 r / min to 1000 r / min.

[0042] Preferably, the friction stir additive equipment controls the advancing speed of the additive tool 3 to be 10 mm / min to 2000 mm / min.

[0043] The friction stir welding additive device used in this embodiment is an existing device and does not belong to the technical improvement of the present invention. Its specific structure refers to the friction stir welding additive device with application number 202310875894.8 previously applied by the applicant, including a base; a beam assembly, the beam assembly is slidably connected to the base along the X-axis direction; a slide assembly, the slide assembly is slidably connected to the beam assembly along the Y-axis direction; a head assembly, the head assembly includes a head frame and an additive body, the machine The head frame is slidably connected to the slide assembly along the Z-axis direction, and the additive body includes a fork ring and a swing cylinder. The fork ring is rotatably connected to the head frame around the C-axis axis, and the C-axis axis is parallel to the Z-axis direction; the swing cylinder is internally connected to a spindle assembly, and the upper part of the spindle assembly is connected to a feeding assembly, and the swing cylinder is rotatably connected to the fork ring around the B-axis axis, and the B-axis axis is parallel to the Y-axis direction; wherein the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The above-mentioned friction stir welding additive equipment allows the additive body to move linearly in the X-axis direction, the Y-axis direction, and the Z-axis direction as a whole, and at the same time, the spindle assembly can also swing around the B-axis axis and the C-axis axis, thereby realizing the five-axis linkage of the friction stir welding additive equipment, greatly improving the flexibility of the structure, and being able to effectively realize the additive manufacturing of components of complex shapes, thereby improving the efficiency and quality of additive manufacturing.

[0044] Based on the friction stir additive equipment with the above structure, when performing additive processing, after the descaled additive substrate 2 is fixed on the positioning fixture of the friction stir additive equipment, the descaled raw material bar 1 is put into the material box of the friction stir additive equipment, the friction stir additive equipment is started, and the additive tool 3 descends to the specified position, rotates forward and pushes out the descaled raw material bar 1 and coats it on the surface of the descaled additive substrate 2. After the additive advances to the specified position, the additive tool 3 is lifted up one layer and feeds the material during the lifting process. After completing the lifting action, it continues to add material on the next layer, and the additive manufacturing of the entire component is completed by repeating the cycle.

[0045] Figure 4 A cross-sectional rendering of the additively manufactured structure without removing the oxide scale is shown; Figure 5 A cross-sectional view of the AM microstructure after oxide scale removal is shown; Figure 5 A comparison chart of the tensile properties data of the additively manufactured structure without removing the oxide scale and the additively manufactured structure after removing the oxide scale is shown; it can be seen from the figure that by removing the oxide scale on the raw material bar material 1 and the additive substrate 2, the metallurgical bonding effect between the layers of the stir friction additively manufactured component is improved, the longitudinal strength of the component is improved, and the problem of longitudinal brittle fracture of the component caused by oxide inclusions is solved.

[0046] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for improving the bonding strength of a friction stir additive manufacturing tissue layer, characterized in that: The specific method is as follows: S1. Remove the oxide scale on the raw material bar, the thickness of the oxide scale removed is in the range of 0.02-0.1mm; S2. Remove the oxide scale on the surface of the additive substrate, the thickness of the oxide scale removed is in the range of 0.02-0.1mm; S3. Fixing the additive substrate from which the oxide skin has been removed; S4. The raw material bar from which oxidation and peeling has been removed is arranged above the additive substrate, and the raw material bar is placed in a vertical state, and the raw material bar is fed toward the additive substrate and controlled to rotate, so that the raw material bar is always in contact with the additive substrate and can rotate and move forward on the additive substrate along a certain trajectory; S5. The raw material bar from which the oxide scale is removed contacts and rubs against the additive substrate during the process of rotating forward, and the end of the raw material bar is softened by heat to form a flowing state, and the material in the flowing state is evenly coated on the surface of the additive substrate from which the oxide scale is removed; S6. When the raw material bar advances to the specified position, the raw material bar is controlled to be lifted up one layer, and the raw material bar is fed during the lifting process. After the raw material bar completes the lifting action, the additive substrate continues to be processed by the next layer of additive.

2. A method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 1, characterized in that: The raw material bar is one of aluminum, magnesium, copper or other metal materials and metal-based composite materials.

3. A method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 1, characterized in that: In step S3, the additive substrate from which the oxide scale has been removed is fixed on a positioning fixture of the friction stir additive equipment.

4. A method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 3, characterized in that: In step S4, the raw material bar is installed on the spindle of the friction stir additive device through the additive tool, the friction stir additive device is used to control the additive tool and the raw material bar to move to the specified position, and the raw material bar is fed toward the additive substrate in the vertical direction through the feeding device of the friction stir additive device; when the raw material bar contacts the additive substrate, the spindle controls the additive tool to rotate, so that the raw material bar and the additive tool generate friction with the additive substrate at the same time.

5. A method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 4, characterized in that: The additive tool is a hollow cylindrical rotating body, which is used to fix the raw material bar from which the oxide scale is removed. The rotating body is connected to the main shaft of the stir friction additive equipment. The stir friction additive equipment provides rotational power through the main shaft, and controls the rotation of the rotating body by the main shaft to realize the rotation of the raw material bar. After the raw material bar is fixed in the rotating body, the end face of the rotating body remains flush with the end face of the raw material bar. When the rotating body rotates, the friction with the additive substrate generates heat to provide a heat source for the raw material bar, which is used to accelerate the softening speed of the end of the raw material bar.

6. A method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 5, characterized in that: The friction stir additive equipment controls the additive tool rotation speed to 300 r / min to 1000 r / min.

7. A method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 6, characterized in that: The friction stir additive equipment controls the advancement speed of the additive tool to 10 mm / min to 2000 mm / min.

8. The method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 1, characterized in that: The layer height of the single-layer additive in step S6 is 0.5 mm to 3 mm.

9. The method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 1, characterized in that: In step S1, the oxide scale on the raw material bar with oxide scale is removed by using an external cylindrical polishing machine.

10. The method for improving the bonding strength of a friction stir additive manufacturing tissue layer according to claim 1, characterized in that: In step S2, a metal wire drawing machine is used to remove the oxide scale on the surface of the additive manufacturing substrate with oxide scale.

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