A method of manufacturing a frame skin feed arm structure

Abstract

This invention provides a manufacturing method for a frame-skinned feeding arm structure, belonging to the field of robotic arm manufacturing technology. The specific manufacturing steps are as follows: S1. Design the blank model of the feeding arm structure; S2. Prepare the lower skin; S3. Perform low-stress, alternating addition and subtraction material processing on the side plates, front plates, rear plates, grid-type reinforcing ribs, and petal-type reinforcing rib bushings; S4. Weld the pre-beveled upper skin to the structure processed in S3; S5. Roughly machine the entire frame; S6. Heat treat the rough-machined frame; S7. Finish machine the heat-treated frame to obtain the feeding arm structure. This invention, through alternating addition and subtraction material processing, high-energy sound beam assistance, and stepped processing, can solve the problems of weak welds and high stress in traditional feeding arms, improve rigidity and lifespan, achieve lightweight, high-efficiency, and low-cost manufacturing, and is suitable for stamping scenarios in new energy vehicles.

Description

Technical Field

[0001] This invention relates to the field of robotic arm manufacturing technology, and in particular to a method for manufacturing a frame-skinned feeding arm structure. Background Technology

[0002] Large-scale stamping production lines in the new energy vehicle sector have become core equipment in the industry due to their efficient and agile production methods. The feeder arm in its high-speed feeding device, as a key actuator, needs to withstand cyclic loads for extended periods, placing extremely high demands on its overall rigidity, fatigue resistance, and service life. However, current feeder arm manufacturing and structural design face numerous technical bottlenecks, making it difficult to meet industry requirements.

[0003] In existing related technologies, such as Chinese patent application publication number CN114393605A, a novel three-dimensional braided robotic arm and its manufacturing method are disclosed. Although the method forms the main body by combining fiber braided preforms with resin impregnation and curing, and uses metal joints to achieve lightweighting, its structure focuses on improving the precision of conventional robotic arms. The combination of the braided main body and the metal joints is difficult to adapt to the high rigidity required by large stamping feeding arms. Moreover, the manufacturing process does not involve complex reinforcing rib structures and additive / subtractive material synergy processes, and cannot achieve a precise balance between strength and lightweighting.

[0004] For example, Chinese patent CN221018363U discloses a centering feeding arm for a conveying device. Although the feeding arm achieves the adjustment of the plate posture and spacing through a three-section arm body and crossbar separation shaft, it relies on traditional mechanical assembly and drive mechanism. The arm body has a large number of welds and residual stress concentration, which makes it prone to cracking under long-term cyclic load. Moreover, it does not adopt innovative manufacturing process to optimize structural performance and cannot solve the inherent problem of weak welded structure strength.

[0005] It is evident that current mainstream feeder arms are mostly aluminum alloy welded structures, which not only have weak welds and high residual stress, leading to easy failure during service, but also make it difficult to achieve complex reinforcing rib designs using traditional manufacturing processes. While additive manufacturing alone can form complex structures, it is prone to stress deformation due to thermal cycling. Therefore, the industry urgently needs a feeder arm manufacturing method that can balance high rigidity and strength, lightweight, long service life, and efficient manufacturing to meet the stable operation requirements of large-scale stamping production lines for new energy vehicles. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing feeding arms, such as weak welded structures, easy stress deformation, and short service life, and to provide a manufacturing method for a frame-skinned feeding arm structure.

[0007] The present invention is achieved through the following technical solution: a method for manufacturing a frame skin feeding arm structure, wherein the feeding arm structure includes a lower skin, side uprights, a front upright, a rear upright, a grid-type reinforcing rib, a petal-type reinforcing rib bushing, and an upper skin.

[0008] The specific manufacturing steps are as follows: S1. Design the blank model of the feeding arm structure. The blank model does not include the upper skin. The lower skin, side plate, front plate, rear plate, grid-type reinforcing rib and petal-type reinforcing rib bushings included therein all have reserved machining allowances. S2. Prepare the lower skin, which also serves as the substrate for additive manufacturing of the side panels, front panels, rear panels, grid-type reinforcing ribs, and petal-type reinforcing rib bushings; S3. The side panels, front panels, rear panels, grid-type reinforcing ribs, and petal-type reinforcing rib bushings are manufactured using an overall low-stress additive-subtractive alternating process. After additive manufacturing, in-situ subtractive manufacturing is performed according to the blank model, alternating to the blank height, while simultaneously machining bevels and weight-reducing holes. During additive manufacturing, a high-energy acoustic beam exciter is arranged on the lower skin to apply ultrasonic action. S4. Weld the pre-beveled upper skin to the structure processed by S3 to form an integral frame; S5. Perform rough machining on the overall frame to create process holes and weight reduction holes; S6. Perform heat treatment on the overall frame after rough machining; S7. The heat-treated overall frame is precision machined to obtain the feeding arm structure.

[0009] This method, through a complete technology chain of "differentiated blank design - substrate reuse - additive and subtractive manufacturing synergy - stepped processing," effectively solves the core pain points in traditional feeder arm manufacturing: Firstly, the targeted margin design of S1 and the lower skin / additive substrate design of S2 reduce material waste and simplify process connections. Secondly, the overall low-stress additive and subtractive manufacturing of S3, combined with the ultrasonic action of a high-energy acoustic beam exciter, can significantly reduce structural residual stress, refine alloy grains, and improve material density, avoiding the problems of easy deformation and cracking in traditional additive manufacturing and weak welds in welded structures. Secondly, the pre-bevel welding of S4 ensures a reliable connection between the upper skin and the main structure. The step-by-step process of roughing, heat treatment, and finishing of S5-S7 can precisely control the structural accuracy and mechanical properties, taking into account both manufacturing efficiency and product quality. Ultimately, it achieves a significant improvement in the overall rigidity and fatigue resistance of the feeding arm, while reducing manufacturing costs and increasing production efficiency. It can also adapt to the high-speed feeding scenario of large stamping production lines for new energy vehicles while ensuring lightweight requirements, providing reliable technology for the high-performance, low-cost, and efficient manufacturing of the feeding arm structure.

[0010] A further improvement of the present invention is that the machining allowance in S1 is set as follows: no allowance is left inside the lower skin; a 4mm machining allowance is reserved on the lower surface of the lower skin; a 50mm machining allowance is reserved on the outer side of the lower skin corresponding to the inner diameter of the petal-shaped reinforcing rib bushing; no allowance is left on the inner side of the side plate, front plate, and rear plate; a 3mm machining allowance is reserved on the outer side of the side plate, front plate, and rear plate; no allowance is left on the outer side and inside of the petal-shaped reinforcing rib bushing; a 5mm machining allowance is reserved on the inner side of the petal-shaped reinforcing rib bushing; and a 5mm machining allowance is reserved on the upper surface of the side plate, front plate, rear plate, mesh reinforcing rib, and petal-shaped reinforcing rib bushing.

[0011] A further improvement of the present invention is that the lower skin mentioned in S2 is a metal sheet, specifically a 2219 aluminum alloy sheet profile with a thickness of 24mm.

[0012] A further improvement of the present invention is that the single additive manufacturing height in S3 is 50mm, and 2319 aluminum alloy wire with a diameter of Φ1.2mm is used as raw material; the in-situ subtractive processing includes machining the outer diameter surface of the side plate, front plate, rear plate, grid-type reinforcing rib, and petal-type reinforcing rib bushing and the interior of the reinforcing rib in place, machining the weight reduction hole and the upper surface flat, and machining "Y"-shaped bevels around the side plate, front plate, rear plate, and grid-type reinforcing rib.

[0013] A further improvement of the present invention is that the upper skin in S4 is made of 2219 aluminum alloy plate with a thickness of 20mm, and a round hole bevel is opened at the position corresponding to the grid-type reinforcing rib; the welding method is MIG welding, and the filler material is 2319 aluminum alloy welding wire with a diameter of Φ1.2mm.

[0014] A further improvement of the present invention is that the roughing process described in S5 includes machining the lower surface and surrounding areas of the lower skin, the side panels, the front panel and the rear panel to the designed dimensions.

[0015] A further improvement of the present invention is that the heat treatment described in S6 is a solution treatment and an aging treatment; specifically, the solution treatment temperature is 540°C and the holding time is 10 hours, and the aging treatment temperature is 175°C and the holding time is 4 hours.

[0016] A further improvement of the present invention is that the high-energy acoustic beam exciter described in S3 is uniformly arranged on the lower skin, which can improve the solidification process of the additive manufacturing alloy and refine the alloy grains.

[0017] A further improvement of the present invention is that the finishing process described in S7 includes machining the assembly positions of the side plate and the petal-shaped reinforcing rib bushing to the design precision.

[0018] A further improvement of the present invention is that the process holes and weight reduction holes described in S5 are formed on the lower skin and the upper skin.

[0019] As can be seen from the above technical solutions, the beneficial effects of the present invention are: 1. This method, through alternating addition and subtraction of materials manufacturing combined with high-energy sound beam assistance, can refine aluminum alloy grains, reduce residual stress, and improve material density; at the same time, the use of 2219 / 2319 aluminum alloy matching welding improves joint strength, significantly enhances the overall rigidity and fatigue resistance of the feeding arm structure, and completely solves the service failure problem of traditional structures.

[0020] 2. This method reduces material waste through differentiated margin design; the step-by-step processing flow is reasonably connected, eliminating the need for complex tooling switching and improving overall manufacturing efficiency; and it integrates additive manufacturing, subtractive manufacturing, and welding processes, eliminating the need for multiple equipment transfers, thereby reducing overall manufacturing costs and balancing high precision and economy.

[0021] 3. This method can achieve lightweight feeding arm while meeting the dual requirements of "lightweight and rigid" for high-speed stamping lines; it also has a long service life and can stably support the feeding operation of large stamped parts, providing a reliable guarantee for the efficient operation of the production line. Attached Figure Description

[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the feeding arm structure according to a specific embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the blank model according to a specific embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of the lower skin structure according to a specific embodiment of the present invention.

[0026] Figure 4 This is a diagram illustrating the arrangement of a high-energy acoustic beam exciter according to a specific embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of the overall framework of a specific embodiment of the present invention.

[0028] Figure 6 This is a demonstration diagram of the rough machining of the overall framework of a specific embodiment of the present invention.

[0029] In the diagram: 1. Lower skin; 101. Mounting position; 2. Side upright plate; 3. Front upright plate; 4. Rear upright plate; 5. Grid-type reinforcing rib; 6. Petal-type reinforcing rib bushing; 7. Upper skin; 8. High-energy sound beam exciter. Detailed Implementation

[0030] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0031] Now refer to Figure 1-6 The following is a description of a specific embodiment: The manufacturing method of the frame skin feeding arm structure of the present invention includes a lower skin 1, a side plate 2, a front plate 3, a rear plate 4, a grid-type reinforcing rib 5, a petal-type reinforcing rib bushing 6, and an upper skin 7. The side plate 2 and the grid-type reinforcing rib 5 are provided with weight reduction holes.

[0032] The specific manufacturing steps are as follows: S1. Design the blank model of the feeding arm structure, referring to... Figure 2 The blank model does not include the upper skin 7, and the lower skin 1, side upright plate 2, front upright plate 3, rear upright plate 4, grid-type reinforcing rib 5 and petal-type reinforcing rib bushing 6 included therein all have reserved machining allowances. The specific machining allowances are set as follows: no allowance is left on the inner upper surface of the lower skin 1; a 4mm machining allowance is reserved on the lower surface of the lower skin 1; a 50mm machining allowance is reserved on the outer side of the lower skin 1 corresponding to the inner diameter of the petal-shaped reinforcing rib sleeve 6; no allowance is left on the inner sides of the side uprights 2, front uprights 3, and rear uprights 4; a 3mm machining allowance is reserved on the outer sides of the side uprights 2, front uprights 3, and rear uprights 4; no allowance is left on the outer side and inner side of the petal-shaped reinforcing rib sleeve 6; a 5mm machining allowance is reserved on the inner side of the petal-shaped reinforcing rib sleeve 6; and a 5mm machining allowance is reserved on the upper surfaces of the side uprights 2, front uprights 3, rear uprights 4, mesh reinforcing ribs 5, and petal-shaped reinforcing rib sleeve 6.

[0033] S2. Prepare the lower skin 1: Refer to Figure 3 The lower skin 1 is made of 2219 aluminum alloy plate with a thickness of 24mm. To facilitate subsequent mounting and clamping, a 50mm machining allowance is reserved around its outer perimeter and at the position corresponding to the inner diameter of the petal-shaped reinforcing rib bushing 6 as mounting position 101.

[0034] S3. The side uprights 2, front uprights 3, rear uprights 4, grid-type reinforcing ribs 5, and petal-type reinforcing rib bushings 6 are manufactured using an integral low-stress alternating addition-subtraction process: Refer to Figure 4 First, according to the cross-sectional positions of each component, the additive manufacturing path is planned manually using programming. 2319 aluminum alloy wire with a diameter of Ф1.2mm is selected as the raw material for additive manufacturing. The additive manufacturing system is started to perform the first stage of additive manufacturing on the above components. During this process, high-energy acoustic beam exciters 8 are evenly arranged on the lower skin 1 to improve the solidification process of the additive alloy and refine the grains by applying ultrasonic action. The process stops when the additive height reaches 50mm. Then, the process is switched to the in-situ subtractive processing system to perform subtractive processing on the first stage of the additive structure, removing the side panels 2 and the front... The outer diameter surfaces of the upright plate 3, the rear upright plate 4, and the petal-shaped reinforcing rib bushing 6, as well as the interior of the reinforcing rib, are machined to the required level, and the upper surface is machined flat. The above additive and subtractive processes are repeated, with each additive section having a height of 50mm, until the overall height reaches the blank model height designed in S1. Finally, using in-situ subtractive processing equipment, the weight reduction holes on the side upright plate 2 and the grid-shaped reinforcing rib 5 are machined to the required level, and the upper surface is machined to the height required by the product design of the feeding arm. A "Y"-shaped bevel is machined around the side upright plate 2, the front upright plate 3, the rear upright plate 4, and the grid-shaped reinforcing rib 5.

[0035] S4. Weld the pre-beveled upper skin 7 to the structure processed by S3 to form an integral frame: Refer to Figure 5 The upper skin 7 is made of 2219 aluminum alloy plate with a thickness of 20mm. It is first processed to the designed external dimensions, and then "Y" shaped bevels are opened around the perimeter. Circular bevels are also opened at the positions corresponding to the grid-type reinforcing ribs 5. The upper skin 7 is welded to the main structure prepared by S3 using MIG welding. The welding filler material is 2319 aluminum alloy welding wire with a diameter of Ф1.2mm.

[0036] S5. Rough machining of the overall frame to create process holes and weight-reduction holes: Refer to... Figure 6 The lower surface and surrounding area of ​​the lower skin 1, the outer sides of the side panels 2, the front panel 3 and the rear panel 4 are machined to the design dimensions, and weight reduction holes and process holes are machined on the lower skin 1 and the upper skin 7.

[0037] S6. Heat treatment of the overall frame after rough machining: According to the grade of the selected aluminum alloy, a solution treatment + aging process is adopted; the specific process is a solution temperature of 540℃ and a holding time of 10h, an aging temperature of 175℃ and a holding time of 4h.

[0038] S7. Finishing the overall frame after heat treatment: Machining the key assembly positions such as the side upright plate 2 and the petal-shaped reinforcing rib bushing 6 to the design accuracy, thus completing the manufacturing of the feeding arm structure.

[0039] The working principle of this method is as follows: First, a blank model is designed using 3D software. Differentiated machining allowances are set for different components such as the lower skin 1, side uprights 2, and petal-shaped reinforcing bushings 6, based on their functional requirements. A 50mm allowance is reserved on the outer side of the lower skin 1 and the corresponding position of the bushing to ensure subsequent mounting stability. A 5mm allowance is reserved on the inner side of the bushing to provide adjustment space for precision machining. A 5mm allowance is reserved on the upper surface of each component to adapt to the alternating additive and subtractive manufacturing process, ensuring the controllability of the manufacturing process from the design stage. Subsequently, a 24mm thick 2219 aluminum alloy plate is used as the lower skin 1 and the additive base plate, providing a stable support foundation for the overall structure. The core manufacturing stage adopts an alternating mode of "arc additive manufacturing - 50mm per segment + in-situ subtractive manufacturing". The additive path is planned by manual programming and precise machining is achieved with Φ1.2mm diameter 2319 aluminum alloy wire. The process involves welding, while simultaneously arranging high-energy acoustic beam exciters 8 evenly on the lower skin 1. This utilizes ultrasonic action to interfere with the alloy solidification process and refine the grains. In-situ milling is used to promptly eliminate additive layer defects and calibrate dimensions, ultimately producing a "Y"-shaped bevel and weight-reducing holes. For the upper skin 7 welding stage, 2219 aluminum alloy plates and 2319 aluminum alloy welding wires of the same material system are used. MIG welding and a round hole bevel design ensure penetration with the grid-type reinforcing ribs 5, forming an overall frame. Subsequent stepped machining further optimizes performance. Rough machining removes redundant allowances and creates process holes to facilitate stress release. A 540℃×10h solution treatment followed by a 175℃×4h aging treatment promotes the precipitation of strengthening phases in the aluminum alloy. Finally, precision machining controls the assembly position accuracy of the side panels 2, petal-shaped reinforcing rib bushings 6, etc., within the design requirements, completing the entire manufacturing process.

[0040] From the perspective of material utilization, this method can significantly reduce material waste through differentiated margin design, avoiding dimensional scrap due to insufficient margin. In terms of structural performance, the alternating additive and subtractive manufacturing process, combined with high-energy sound beam assistance, reduces residual stress in the structure, thereby refining the grain size from 50μm in traditional additive manufacturing to below 15μm, greatly improving material density and effectively solving the problem of easy deformation and cracking in additive manufacturing. In terms of connection strength, the material matching of 2219 / 2319 aluminum alloy and post-weld treatment, along with hole positions, improve the strength of the welded joint, far exceeding the strength of traditional dissimilar material welding. In terms of comprehensive performance and efficiency, this method can improve overall manufacturing efficiency through stepped processing. The synergistic effect of heat treatment and finishing allows the feeding arm structure to achieve lightweight while maintaining high bending stiffness and meeting load requirements in terms of fatigue life, reducing overall manufacturing costs. It is fully adaptable to the high-speed feeding scenario of large stamping production lines for new energy vehicles and extends service life.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for manufacturing a frame skin feeding arm structure, the feeding arm structure comprising a lower skin (1), side uprights (2), a front upright (3), a rear upright (4), grid-type reinforcing ribs (5), petal-type reinforcing rib bushings (6), and an upper skin (7), characterized in that, Includes the following steps: S1. Design the blank model of the feeding arm structure. The blank model does not include the upper skin (7). The lower skin (1), side plate (2), front plate (3), rear plate (4), grid-type reinforcing rib (5) and petal-type reinforcing rib bushing (6) included therein are all reserved with machining allowance. S2. Prepare the lower skin (1), which is also used as the substrate for additive manufacturing of the side plate (2), front plate (3), rear plate (4), grid-type reinforcing rib (5), and petal-type reinforcing rib bushing (6); S3. The side plate (2), front plate (3), rear plate (4), grid-type reinforcing rib (5) and petal-type reinforcing rib bushing (6) are manufactured in an overall low-stress alternating additive and subtractive manufacturing process. After additive manufacturing, the blank model is processed in situ using the subtractive manufacturing process, alternating to the blank height, while simultaneously processing the bevel and weight reduction holes. During additive manufacturing, a high-energy acoustic beam exciter (8) is arranged on the lower skin (1) to apply ultrasonic action. S4. Weld the pre-beveled upper skin (7) to the structure processed by S3 to form an integral frame; S5. Perform rough machining on the overall frame to create process holes and weight reduction holes; S6. Perform heat treatment on the overall frame after rough machining; S7. The heat-treated overall frame is precision machined to obtain the feeding arm structure.

2. The manufacturing method of a frame skin feeding arm structure according to claim 1, characterized in that, The lower skin (1) mentioned in S2 is a metal sheet, specifically a 2219 aluminum alloy sheet with a thickness of 24mm.

3. The manufacturing method of a frame skin feeding arm structure according to claim 2, characterized in that, The single additive manufacturing height described in S3 is 50mm, and 2319 aluminum alloy wire with a diameter of Φ1.2mm is used as raw material; the in-situ subtractive processing includes machining the outer diameter surface and the inside of the reinforcing ribs of the side plate (2), front plate (3), rear plate (4), grid-type reinforcing rib (5), and petal-type reinforcing rib bushing (6) to the correct position, machining the weight reduction hole and the upper surface flat, and machining "Y"-shaped bevels around the side plate (2), front plate (3), rear plate (4), and grid-type reinforcing rib (5).

4. The manufacturing method of a frame skin feeding arm structure according to claim 3, characterized in that, The upper skin (7) described in S4 is made of 2219 aluminum alloy plate with a thickness of 20mm. A round hole bevel is provided at the position corresponding to the grid-type reinforcing rib (5). The welding method is MIG welding, and the filler material is 2319 aluminum alloy welding wire with a diameter of Φ1.2mm.

5. The manufacturing method of a frame skin feeding arm structure according to claim 4, characterized in that, The roughing process described in S5 includes machining the lower surface and surrounding areas of the lower skin (1), the side panels (2), the front panel (3), and the outer side of the rear panel (4) to the designed dimensions.

6. The manufacturing method of a frame skin feeding arm structure according to claim 5, characterized in that, The heat treatment described in S6 is solution treatment and aging treatment; the specific process is a solution treatment temperature of 540℃ and a holding time of 10h, and an aging treatment temperature of 175℃ and a holding time of 4h.

7. The manufacturing method of a frame skin feeding arm structure according to claim 6, characterized in that, The high-energy acoustic beam exciter (8) described in S3 is uniformly arranged on the lower skin (1), which can improve the solidification process of additive manufacturing alloys and refine alloy grains.

8. A method for manufacturing a frame skin feeding arm structure according to claim 7, characterized in that, The finishing process described in S7 includes machining the assembly positions of the side plate (2) and the petal-shaped reinforcing bushing (6) to the design precision.

9. A method for manufacturing a frame skin feeding arm structure according to claim 8, characterized in that, The process holes and weight reduction holes described in S5 are opened on the lower skin (1) and the upper skin (7).

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