A method of welding a resin-based composite material that realizes enhanced fiber bonding

Abstract

This invention relates to a welding method for resin-based composite materials that achieves reinforcing fiber bonding. The invention addresses the technical problem of low joint strength in resin-based composite materials obtained through conventional ultrasonic welding. The method comprises: first, selecting the joint type and processing of the composite material; second, heating the area to be welded, removing the resin matrix to expose the reinforcing fibers; third, using horizontal vibration ultrasonic welding to weld the reinforcing fibers, creating connections between them; and fourth, re-casting resin into the welded area after the fibers are bonded. This invention not only achieves bonding of the resin matrix but also the bonding of its internal carbon fibers, resulting in a high-strength joint. This method can be used to weld various composite materials, such as carbon fiber / glass fiber resin-based composites. This invention is used for welding resin-based composite materials with reinforcing fiber bonding.

Description

Technical Field

[0001] This invention relates to the field of welding methods for resin-based composite materials. Background Technology

[0002] Resin-based composite materials are widely used in aerospace, advanced manufacturing, and other fields due to their low density and high strength. Similar to other materials, it is difficult to achieve one-piece molding of complex components using resin-based composite materials. Therefore, welding or bonding methods are often used in practical applications to fabricate complex components from simple resin-based composite parts for practical use. Various welding methods exist for resin-based composite materials, such as induction welding, ultrasonic welding, and resistance welding. Currently, ultrasonic welding is the most widely used welding method for resin-based composite materials, offering advantages such as high welding efficiency, low welding cost, and simple operation.

[0003] However, in traditional ultrasonic welding, regardless of whether energy-conducting ribs are used, the welding process only achieves the connection between resins, without effectively connecting the internal fibers, such as carbon fiber or glass fiber. Therefore, the joint strength of resin-based composite materials obtained by traditional ultrasonic welding is generally low. Summary of the Invention

[0004] This invention provides a welding method for resin-based composite materials that achieves reinforced fiber bonding, in order to solve the technical problem of low joint strength of resin-based composite materials obtained by conventional ultrasonic welding.

[0005] A welding method for achieving fiber-reinforced composite materials, specifically comprising the following steps:

[0006] 1. Pre-clamp the resin-based composite material joint to be welded, heat the area to be welded, remove the resin matrix of the area to be welded, and expose part of the reinforcing fiber;

[0007] 2. The exposed reinforcing fibers of the joint to be welded, which were processed in step 1, are welded together using a horizontal vibration ultrasonic welding method, so that the reinforcing fibers of the joint to be welded are connected together.

[0008] 3. Re-cast the reinforcing fibers connected in step 2 with resin, vibrate to assist filling during casting, and apply pressure to form after casting to complete the process.

[0009] Furthermore, the resin-based composite material described in step one is carbon fiber / glass fiber reinforced polyphenylene sulfide or carbon fiber / glass fiber reinforced polyether ether ketone.

[0010] Furthermore, the heating temperature described in step one is 20 to 50°C higher than the melting temperature of the resin matrix in the resin-based composite material.

[0011] Furthermore, the welding process parameters in step two are as follows: the ultrasonic power is 100-3000W, the pre-ultrasonic pressure holding time is 0.1s-100s, the ultrasonic time is 0.01s-100s, the ultrasonic head pressure is 0.01MPa-2MPa, the ultrasonic frequency is 15kHz-60kHz, and the ultrasonic amplitude is 1μm-100μm.

[0012] Furthermore, the parameters for controlling the vibration in step three are: power of 10 to 3000W, vibration time of 10 to 100 seconds, vibration frequency of 15 Hz to 60 kHz, and amplitude of 1 μm to 1 mm.

[0013] Furthermore, the pressure applied in step three is 0.01 MPa to 5 MPa.

[0014] This invention achieves high-strength welding of fiber-reinforced resin matrix composites through resin removal, ultrasonic welding of reinforcing fibers, and resin casting. The invention comprises the following steps: First, selecting the joint type and processing of the composite material; second, heating the area to be welded, removing the resin matrix to expose the reinforcing fibers; third, using horizontal vibration ultrasonic welding to weld the reinforcing fibers, creating connections between them; fourth, after the fibers are joined, re-casting resin into the welding area, using vibration combined with pressure to ensure good resin filling between the fibers, ultimately completing the welding.

[0015] Beneficial effects of this invention:

[0016] To obtain high-strength resin-based composite material joints and promote their widespread application in modern manufacturing, this invention proposes a novel multi-step welding method for resin-based composite materials. This method enables the connection of reinforcing fibers within the resin-based composite material, effectively improving the joint strength.

[0017] In this invention, the resin at the welding location is first removed to expose the reinforcing fibers. Then, a horizontal ultrasonic vibration welding method is used to directly weld the reinforcing microstructures. Ultrasonic welding can weld many new and difficult-to-weld materials, such as metals and ceramics, thus enabling the direct bonding of carbon fibers or glass fibers. After achieving the internal micro-connection using ultrasonic vibration, resin is poured into the microstructures, and a combination of pressure and vibration is used to achieve a tight bond between the resin and fibers. This ultimately yields a high-strength resin-based composite material joint.

[0018] 1. This invention requires no special resin molding technology or equipment, resulting in low cost;

[0019] 2. This invention not only achieves the connection of the resin matrix, but also the connection of the carbon fibers inside it, resulting in a joint with high strength;

[0020] 3. This method can achieve welding of various composite materials, such as resin-based composite materials like carbon fiber / glass fiber.

[0021] This invention relates to the welding of resin-based composite materials for reinforcing fiber connections. Attached Figure Description

[0022] Figure 1 A specific embodiment of a joint type for pre-clamping a pair of resin-based composite material heads to be welded.

[0023] Figure 2 This is a schematic diagram illustrating the removal of the resin matrix in the area to be soldered, exposing some of the reinforcing fibers, as described in Implementation Method 1.

[0024] Figure 3 This is a schematic diagram of a specific implementation method for horizontal vibration welding of reinforcing fibers;

[0025] Figure 4 This is a schematic diagram illustrating the casting and pressure application molding process in a specific implementation method.

[0026] Figure 5 A characteristic diagram of the cross-section of the welded joint is obtained for an example. Detailed Implementation

[0027] Specific Implementation Method 1: This implementation method provides a welding method for resin-based composite materials to achieve reinforced fiber bonding, specifically following these steps:

[0028] 1. Pre-clamp the resin-based composite material joint to be welded, heat the area to be welded, remove the resin matrix of the area to be welded, and expose part of the reinforcing fiber;

[0029] 2. The exposed reinforcing fibers of the joint to be welded, which were processed in step 1, are welded together using a horizontal vibration ultrasonic welding method, so that the reinforcing fibers of the joint to be welded are connected together.

[0030] 3. Re-cast the reinforcing fibers connected in step 2 with resin, vibrate to assist filling during casting, and apply pressure to form after casting to complete the process.

[0031] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the resin-based composite material mentioned in step one is carbon fiber / glass fiber reinforced polyphenylene sulfide or carbon fiber / glass fiber reinforced polyetheretherketone. Everything else is the same as in Specific Implementation Method One.

[0032] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the pre-clamping described in step one overlaps the resin-based composite material, with an overlap width of 10mm. Everything else is the same as in Specific Implementation Method One or Two.

[0033] Specific Implementation Method Four: This implementation method differs from one of Specific Implementation Methods One to Three in that the heating temperature in step one is 20-50°C higher than the melting temperature of the resin matrix in the resin-based composite material. Otherwise, it is the same as one of Specific Implementation Methods One to Three.

[0034] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: in step one, tweezers or a knife are used to remove the heated and melted resin matrix. Everything else is the same as in Specific Implementation Methods One to Four.

[0035] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: in step two, the exposed reinforcing fibers of the joint to be welded are interlaced and overlapped. Everything else is the same as in Specific Implementation Methods One to Five.

[0036] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the welding process parameters in step two are as follows: the ultrasonic power is 100–3000W; the pre-ultrasonic pressure holding time is 0.1s–100s; the ultrasonic time is 0.01s–100s; the ultrasonic head pressure is 0.01MPa–2MPa; the ultrasonic frequency is 15kHz–60kHz; and the ultrasonic amplitude is 1μm–100μm. All other parameters are the same as in Specific Implementation Methods One to Six.

[0037] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step three, the ultrasonic head is removed first, and then the welding area is re-cast with resin. Everything else is the same as in Specific Implementation Methods One to Seven.

[0038] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the parameters for controlling the vibration in step three are: power of 10–3000W, vibration time of 10–100s, vibration frequency of 15Hz–60kHz, and amplitude of 1μm–1mm. Everything else is the same as in Specific Implementation Methods One to Eight.

[0039] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the pressure applied in step three is 0.01 MPa to 5 MPa. Everything else is the same as in Specific Implementation Methods One to Nine.

[0040] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0041] Example:

[0042] A welding method for achieving fiber-reinforced composite materials, specifically comprising the following steps:

[0043] 1. The workpiece to be welded consists of two pieces of resin-based composite material (carbon fiber reinforced PPS) base material, with dimensions of 80mm×30mm×4mm. The two base materials are overlapped and placed with an overlap width of 10mm. The area to be welded is heated to 320℃ until the PPS matrix melts. The molten resin is removed using tweezers, knives, etc., to expose the carbon fiber in the matrix.

[0044] 2. The exposed carbon fibers of the head to be welded in step one are welded using a horizontal vibration ultrasonic welding method. The welding parameters are as follows: ultrasonic power is 300W, pre-ultrasonic pressure holding time is 1s, ultrasonic time is 0.05s, ultrasonic head pressure is 0.2MPa, ultrasonic frequency is 25kHz, ultrasonic amplitude is 20μm, and the carbon fibers of the head to be welded are connected together.

[0045] 3. After welding in step two, remove the ultrasonic head and pour PPS resin into the welding area. Vibration assists filling during pouring, with a vibration frequency of 100Hz. After pouring, apply 0.1MPa pressure to form the welded joint, thus completing the process.

[0046] Figure 5 The image shows a characteristic diagram of the cross-section of the welded joint. As can be seen from the image, the carbon fibers are bonded together, and there is obvious welding between different carbon fibers. This is due to the action of the ultrasonic waves in step two.

[0047] The mechanical properties of the joint obtained in the embodiment are 75.3 MPa, which is more than twice as high as the joint strength obtained by ultrasonic welding (which is up to about 35 MPa) compared to the current lap joint method.

Claims

1. A welding method for resin-based composite materials to achieve reinforced fiber bonding, characterized in that... This method is specifically carried out in the following steps:

1. Pre-clamp the resin-based composite material joint to be welded, heat the area to be welded, remove the resin matrix of the area to be welded, and expose part of the reinforcing fiber; 2. The exposed reinforcing fibers of the joint to be welded, which were processed in step 1, are welded together using a horizontal vibration ultrasonic welding method, so that the reinforcing fibers of the joint to be welded are connected together.

3. Re-cast the reinforcing fibers connected in step 2 with resin, vibrate to assist filling during casting, apply pressure to form after casting, and complete the process. The welding process parameters described in step two are as follows: ultrasonic power is 100~3000W, pre-ultrasonic pressure holding time is 0.1s~100s, ultrasonic time is 0.01s~100s, ultrasonic head pressure is 0.01MPa~2MPa, ultrasonic frequency is 15kHz~60kHz, and ultrasonic amplitude is 1μm~100μm. The parameters for controlling the vibration in step three are: power of 10~3000W, vibration time of 10s~100s; vibration frequency of 15Hz~60kHz, and amplitude of 1μm~1mm. The pressure applied in step three is 0.01 MPa to 5 MPa.

2. The welding method for achieving fiber-reinforced composite materials according to claim 1, characterized in that... The resin-based composite material mentioned in step one is carbon fiber / glass fiber reinforced polyphenylene sulfide or carbon fiber / glass fiber reinforced polyether ether ketone.

3. The welding method for achieving fiber-reinforced composite materials according to claim 1, characterized in that... The pre-assembled clamps described in step one overlap the resin-based composite material with an overlap width of 10mm.

4. The welding method for achieving fiber-reinforced composite materials according to claim 1, characterized in that... The heating temperature described in step one is 20-50°C higher than the melting temperature of the resin matrix in the resin-based composite material.

5. The welding method for achieving fiber-reinforced composite materials according to claim 1, characterized in that... Step 1 involves using tweezers or a knife to remove the heated and melted resin matrix.

6. The welding method for achieving fiber-reinforced composite materials according to claim 1, characterized in that... Step two involves interlacing and overlapping the exposed reinforcing fibers of the joint to be welded.

7. The welding method for achieving fiber-reinforced composite materials according to claim 1, characterized in that... Step 3: First, remove the ultrasonic head, then re-pour resin into the welding area.

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