A method of protected predrilled hole z-pin insertion

Abstract

The application discloses a kind of preformed hole type Z-pin implantation methods with protection, belong to composite Z-pin technical field, comprising: continuous Z-pin is placed in implantation head, pass through the roller set, catheter and hollow thin-walled steel needle of implantation head, control implantation head, make hollow thin-walled steel needle pierce composite material structure, and rise, through the cooperation of roller set and auxiliary cutter realizes the discretization of continuous Z-pin and the effective residence of discrete Z-pin in composite material structure, complete Z-pin implantation.The application can effectively protect Z-pin during implantation, and guarantee the implantation path of Z-pin, and without preparing specific length discrete Z-pin in advance, without preparing foam preform, expand the application range of Z-pin reinforcement process, while greatly improving the implantation efficiency of Z-pin, and good practicality.

Description

A Protective Pre-drilled Hole Z-pin Implantation Method Technical Field

[0001] This invention belongs to the field of composite material Z-pin technology, specifically relating to a protected pre-drilled hole Z-pin implantation method. Background Technology

[0002] Laminated composite materials often exhibit poor interlaminar properties and are prone to delamination damage. Therefore, researchers have developed various interlaminar strengthening methods. Z-pin strengthening has attracted widespread attention due to its low cost, ease of operation, and significant toughening effect. Currently, there are two main Z-pin implantation processes: ultrasonic implantation and pre-drilled hole implantation. The former uses a metal hammer to vibrate at a specific frequency (20–30 kHz) and amplitude (20–30 μm), continuously hammering the rear end of a pre-cut Z-pin to "knock" it into the workpiece. The latter involves using a solid steel needle to create a pre-drilled hole at the target implantation location, and then inserting the pre-cut Z-pin into it.

[0003] However, the application of Z-pin reinforcement is currently limited to small areas such as universities, laboratories, and related research institutes, with almost no engineering applications. The fundamental reason lies in the three major bottlenecks of traditional Z-pin implantation technology: 1) Because Z-pins are usually prepared using pultrusion, they are not fully cured, resulting in low strength and flexural stiffness. Therefore, during ultrasonic implantation (especially for thick prepregs), Z-pins are prone to deviating from the intended path and splitting at the tip. 2) Ultrasonic implantation requires the use of foam preforms, which are often prepared manually. Due to the small Z-pin spacing (3-8mm), this is extremely labor-intensive when dealing with large workpieces. Furthermore, foam preforms are usually based on rigid foam, making it difficult to bond them together when reinforcing curved workpieces. Therefore, its application is often limited to flat workpieces. 3) Similar to the ultrasonic implantation process, the pre-drilled hole implantation process also requires the pre-preparation of discrete Z-pins. Without the assistance of automated equipment, the workload is enormous. In addition, the pre-drilled hole will shrink to a certain extent after the steel needle is pulled out. Therefore, the diameter of the steel needle often needs to be 1.5 times or more the diameter of the Z-pin to ensure that the Z-pin can be smoothly inserted into the pre-drilled hole. This will have a significant negative impact on the in-plane properties of the composite material.

[0004] After reviewing a large amount of relevant technical data, it was found that the current Z-pin implantation methods in China cannot meet the needs of practical engineering applications. Therefore, if some innovations can be introduced based on the existing Z-pin implantation methods, so that Z-pins can not only achieve efficient implantation of composite material structures, but also significantly improve the overall performance of composite material structures, this would be of great significance for the large-scale application of composite materials in various fields. Summary of the Invention

[0005] To address the aforementioned shortcomings in existing technologies, this invention provides a protected pre-drilled hole Z-pin implantation method that can solve the following technical problems: the need to prepare discrete Z-pins and foam preforms in advance before implantation; the problem that Z-pins are prone to deviating from the planned penetration path and splitting at the front end during implantation due to insufficient bending stiffness and strength; the difficulty in reinforcing curved composite material structures with Z-pins; and the difficulty in achieving automated continuous Z-pin implantation.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is: a protected pre-drilled hole Z-pin implantation method, comprising the following steps:

[0007] S1: Place the continuous Z-pin in the implant head, pass it through the roller assembly, catheter and hollow thin-walled steel needle of the implant head, and make the front end of the continuous Z-pin flush with the front end of the hollow thin-walled steel needle.

[0008] S2: Control the implant head so that the hollow thin-walled steel needle of the implant head pierces the composite material structure and rises, so that the front end of the hollow thin-walled steel needle retracts into the interior of the composite material structure. At the same time, control the roller group of the implant head to lock tightly, so that the continuous Z-pin and the hollow thin-walled steel needle remain relatively stationary.

[0009] S3: Control the implant head to make the hollow thin-walled steel needle of the implant head exit the interior of the composite material structure. At the same time, control the roller group of the implant head to rotate so that the continuous Z-pin remains relatively stationary with respect to the composite material structure.

[0010] S4: Use an auxiliary tool to cut the continuous Z-pin between the front end of the hollow thin-walled steel needle and the surface of the composite material structure to obtain discrete Z-pin residing in the composite material structure.

[0011] S5: Control the roller assembly of the implantation head to rotate, retract the continuous Z-pins exposed at the front end of the hollow thin-walled steel needle, and control the implantation head to push the discrete Z-pins exposed on the surface of the composite material structure into the composite material structure.

[0012] S6: Change the spatial position of the implant head into the composite material structure, and repeat S2 to S5 to continuously implant Z-pins into the composite material structure.

[0013] The beneficial effects of this invention are as follows: This invention places continuous Z-pins inside hollow thin-walled steel needles and inserts both into a composite material structure. The use of rollers and auxiliary cutters achieves the discretization of continuous Z-pins and their effective retention within the composite material structure. The hollow thin-walled steel needles enhance the overall strength and bending stiffness of the Z-pin implant, ensuring the Z-pins are well protected throughout the implantation process, preventing tip splitting, and effectively guaranteeing the implantation path. Furthermore, after implanting continuous Z-pins of appropriate length, this invention uses auxiliary cutters to trim the Z-pins, eliminating the need for pre-preparing discrete Z-pins of specific lengths or prefabricated foam bodies. By adjusting the implant head angle, this invention can successfully implant Z-pins into curved workpieces. This novel pre-drilled hole Z-pin implantation process not only retains the advantages of traditional pre-drilled hole Z-pin implantation process, such as large Z-pin implantation thickness and minimal impact on Z-pin integrity, but also greatly expands the application range of Z-pin reinforcement technology and significantly improves Z-pin implantation efficiency, making it highly practical.

[0014] Furthermore: the roller assembly is used to control the movement of the continuous Z-pin in the conduit and the hollow thin-walled steel needle by rotation, wherein the inner diameter of the conduit is larger than the diameter of the continuous Z-pin; and the inner diameter of the hollow thin-walled steel needle is equal to the diameter of the continuous Z-pin.

[0015] The beneficial effects of the above-mentioned further solution are: by using roller assembly, catheter and hollow thin-walled steel needle, the continuous Z-pin in the implant head can be controlled to ensure that the continuous Z-pin can smoothly enter the interior of the composite material structure.

[0016] Furthermore, the specific steps of S2 are as follows:

[0017] S201: Control the spatial orientation of the implant head, so that the implant head reaches the specified position and posture;

[0018] S202: Control the descent of the implant head so that the hollow thin-walled steel needle of the implant head and the continuous Z-pin pierce the composite material structure together;

[0019] S203: During S202, the roller assembly of the implant head locks the continuous Z-pin, so that the relative position of the continuous Z-pin and the hollow thin-walled steel needle remains unchanged;

[0020] S204: Control the rise of the implant head so that the front end of the hollow thin-walled steel needle of the implant head and the continuous Z-pin retract into the interior of the composite material structure.

[0021] S205: During S204, the roller assembly of the implantation head locks the continuous Z-pin, so that the relative position of the continuous Z-pin and the hollow thin-walled steel needle remains unchanged.

[0022] The beneficial effects of the above-mentioned further solutions are: by using hollow thin-walled steel needles and roller sets, continuous Z-pins can be implanted into composite material structures without bending, thereby improving the quality of implanted Z-pins.

[0023] Furthermore, the specific steps of S5 are as follows:

[0024] S501: Control the roller assembly of the implantation head to rotate, retract the continuous Z-pin that exposes the front end of the hollow thin-walled steel needle, and make the front end of the continuous Z-pin flush with the front end of the hollow thin-walled steel needle.

[0025] S502: Controls the roller assembly of the implantation head to lock tightly, so that the relative position of the continuous Z-pin and the hollow thin-walled steel needle remains unchanged;

[0026] S503: Control the descent of the implant head, and use continuous Z-pins and hollow thin-walled steel needles to push the discrete Z-pins exposed on the surface of the composite material structure into the composite material structure.

[0027] The beneficial effect of the above-mentioned further solution is that by locking the continuous Z-pins with rollers, the Z-pins that extend beyond the surface of the composite material structure can be pressed into the composite material structure, and the length of the Z-pins residing in the composite material structure can be precisely controlled.

[0028] Furthermore: the discrete Z-pin residing in the composite material structure has a length that is a set threshold of the thickness at the implantation location of the composite material structure.

[0029] The beneficial effects of the above-mentioned further solutions are: ensuring the implantation thickness of the Z-pin in the composite material structure, and ensuring that the Z-pin does not protrude after the composite material is cured. Attached Figure Description

[0030] Figure 1 illustrates a protected pre-drilled hole Z-pin implantation method according to the present invention;

[0031] Figure 2 is a schematic diagram of the hollow thin-walled steel needle in this invention;

[0032] Figure 3 is a cross-sectional schematic diagram of the implant head without continuous Z-pins in this invention;

[0033] Figure 4 is a cross-sectional schematic diagram of the implant head piercing the composite material structure under the condition of continuous Z-pin in the present invention;

[0034] Figure 5 is a cross-sectional schematic diagram of the present invention in which the implant head is completely removed from the composite material structure and the continuous Z-pin remains in the composite material structure under the condition of continuous Z-pin;

[0035] Figure 6 is a cross-sectional schematic diagram of discrete Z-pins residing in the composite material structure in this invention;

[0036] Among them, 1. continuous Z-pin, 2. roller group, 3. conduit, 4. hollow thin-walled steel needle, 5. composite material structure, 6. coarse connecting rod, 7. auxiliary tool, and 8. discrete Z-pin. Detailed Implementation

[0037] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0038] Z-pin reinforcement is a technique used to enhance the interlaminar properties of composite materials. It mainly involves inserting tiny metal or non-metal rods (called Z-pins) into the uncured composite material to improve its interlaminar fracture toughness and shear strength. The Z-pins can be made of metal (such as stainless steel, aluminum alloy, titanium alloy, etc.) or non-metal (such as carbon fiber, glass fiber, Kevlar, etc.), and their diameter is usually between 0.2 mm and 1.0 mm, with the most commonly used diameters being 0.3 mm and 0.5 mm.

[0039] Figure 2 shows a schematic diagram of the hollow thin-walled steel needle in this invention; Figure 3 shows a cross-sectional schematic diagram of the implant head without continuous Z-pins in this invention; Figure 4 shows a cross-sectional schematic diagram of the implant head penetrating the composite material structure with continuous Z-pins in this invention; Figure 5 shows a cross-sectional schematic diagram of the implant head exiting the composite material structure with continuous Z-pins in this invention, leaving the continuous Z-pins residing in the composite material structure; Figure 6 shows a cross-sectional schematic diagram of discrete Z-pins residing in the composite material structure in this invention; Referring to Figures 2 to 6, a protected pre-drilled hole Z-pin implantation method of this invention will be described.

[0040] As shown in Figure 1, a protected pre-drilled hole Z-pin implantation method according to the present invention includes the following steps:

[0041] S1: Place the continuous Z-pin 1 in the implant head, pass it through the roller assembly 2, catheter 3 and hollow thin-walled steel needle 4 of the implant head, and make the front end of the continuous Z-pin 1 flush with the front end of the hollow thin-walled steel needle 4.

[0042] In one embodiment of the present invention, the roller assembly 2 can control the movement of Z-pin 1 in the conduit 3 and the hollow thin-walled steel needle 4 by rotation and locking; the inner diameter of the conduit 3 is larger than the diameter of the continuous Z-pin 1; the inner diameter of the hollow thin-walled steel needle 4 is the same as the diameter of the continuous Z-pin 1; the hollow thin-walled steel needle 4 is detachable and replaceable; and the wall thickness of the hollow thin-walled steel needle 4 is ≤0.15mm.

[0043] S2: Control the implant head so that the hollow thin-walled steel needle 4 of the implant head pierces the composite material structure 5 and rises, so that the front end of the hollow thin-walled steel needle 4 retracts into the interior of the composite material structure 5. At the same time, control the roller group 2 of the implant head to lock tightly, so that the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remain relatively stationary.

[0044] In one embodiment of the present invention, the implant head is mounted on a robotic arm, and the spatial orientation of the implant head is adjusted by controlling the movement of the robotic arm.

[0045] The specific steps of S2 are as follows:

[0046] S201: Control the spatial orientation of the implant head, so that the implant head reaches the specified position and posture;

[0047] S202: Control the descent of the implant head so that the hollow thin-walled steel needle 4 of the implant head and the continuous Z-pin 1 pierce the composite material structure 5 together;

[0048] S203: During S202, the roller assembly 2 of the implantation head locks the continuous Z-pin 1, so that the relative position of the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remains unchanged;

[0049] S204: Control the rise of the implant head so that the front end of the hollow thin-walled steel needle 4 of the implant head and the continuous Z-pin 1 retract together into the interior of the composite material structure 5;

[0050] S205: During S204, the roller assembly 2 of the implantation head locks the continuous Z-pin 1, so that the relative position of the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remains unchanged.

[0051] S3: Control the implant head to make the hollow thin-walled steel needle 4 of the implant head exit the interior of the composite material structure 5. At the same time, control the roller group 2 of the implant head to rotate so that the continuous Z-pin 1 remains relatively stationary with the composite material structure 5.

[0052] S4: Use the auxiliary tool 7 to cut the continuous Z-pin1 between the front end of the hollow thin-walled steel needle 4 and the surface of the composite material structure 5 to obtain the discrete Z-pin 8 residing in the composite material structure 5;

[0053] In one embodiment of the present invention, the discrete Z-pin 8 that ultimately resides in the composite material structure has a length that is a set threshold of the thickness of the composite material structure 5 at the implantation location, which can be set to 90% to 95%.

[0054] S5: Control the roller assembly 2 of the implantation head to rotate, retract the continuous Z-pin 1 exposed at the front end of the hollow thin-walled steel needle 4, and control the implantation head to push the discrete Z-pin 8 exposed on the surface of the composite material structure 5 into the composite material structure 5, thus completing the Z-pin implantation at the current puncture position of the composite material structure.

[0055] The specific steps for S5 are as follows:

[0056] S501: Control the roller assembly 2 of the implantation head to rotate, retract the continuous Z-pin 1 exposed at the front end of the hollow thin-walled steel needle 4, so that the front end of the continuous Z-pin 1 is flush with the front end of the hollow thin-walled steel needle 4.

[0057] S502: Control the roller assembly 2 of the implantation head to lock tightly, so that the relative position of the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remains unchanged;

[0058] S503: Control the descent of the implant head, and use the continuous Z-pin 1 and the hollow thin-walled steel needle 4 to push the discrete Z-pin 8 exposed on the surface of the composite material structure 5 into the composite material structure 5, thus completing the Z-pin implantation at the current puncture position of the composite material structure.

[0059] S6: Change the spatial position of the implant head into the composite material structure 5, and repeat S2 to S5 to continuously implant Z-pins into the composite material structure 5.

[0060] The beneficial effects of this invention are as follows: This invention places continuous Z-pins inside hollow thin-walled steel needles and inserts both into the composite material structure. The use of rollers and auxiliary cutters achieves the discretization of continuous Z-pins and their effective retention within the composite material structure. The hollow thin-walled steel needles enhance the overall strength and bending stiffness of the Z-pin implant, ensuring good protection of the Z-pins throughout the implantation process, preventing tip splitting, and effectively guaranteeing the implantation path. Furthermore, after implanting continuous Z-pins of appropriate length, the invention uses auxiliary cutters to trim the Z-pins, eliminating the need for pre-preparing discrete Z-pins of specific lengths or prefabricated foam bodies. By adjusting the implant head angle, this invention can successfully implant Z-pins into curved workpieces. This novel pre-drilled hole implantation process not only retains the advantages of traditional pre-drilled hole implantation processes, such as large implantation thickness and minimal impact on the in-plane properties of the composite material structure, but also greatly expands the application range of Z-pin reinforcement technology and significantly improves Z-pin implantation efficiency, demonstrating good practicality.

Claims

1. A protected pre-drilled hole Z-pin implantation method, characterized in that, Includes the following steps: S1: Place the continuous Z-pin (1) in the implant head, passing through the roller assembly (2), catheter (3), and hollow thin-walled steel needle (4) of the implant head, and make the front end of the continuous Z-pin (1) flush with the front end of the hollow thin-walled steel needle (4); S2: Control the implant head so that the hollow thin-walled steel needle (4) of the implant head pierces the composite material structure (5) and rises, so that the front end of the hollow thin-walled steel needle (4) retracts into the interior of the composite material structure (5). At the same time, control the roller assembly (2) of the implant head to lock tightly, so that the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remain relatively stationary; S3: Control the implant head so that the hollow thin-walled steel needle (4) of the implant head exits the composite material structure (5). Inside the implant head (5), the roller assembly (2) of the implant head is rotated to keep the continuous Z-pin (1) and the composite material structure (5) relatively stationary; S4: The auxiliary cutter (7) is used to cut the continuous Z-pin (1) between the front end of the hollow thin-walled steel needle (4) and the surface of the composite material structure (5) to obtain the discrete Z-pin (8) residing in the composite material structure (5); S5: The roller assembly (2) of the implant head is rotated to retract the continuous Z-pin (1) exposed at the front end of the hollow thin-walled steel needle (4), and the implant head is controlled to push the discrete Z-pin (8) exposed on the surface of the composite material structure (5) into the composite material structure (5); S6: Change the spatial position of the implant head into the composite material structure (5) and repeat S2 to S5 to continuously implant Z-pins into the composite material structure (5); the roller group (2) is used to control the movement of the continuous Z-pin (1) in the catheter (3) and the hollow thin-walled steel needle (4) by rotation. The inner diameter of the catheter (3) is larger than the diameter of the continuous Z-pin (1); the inner diameter of the hollow thin-walled steel needle (4) is equal to the diameter of the continuous Z-pin (1).

2. The protected pre-drilled hole Z-pin implantation method according to claim 1, characterized in that, The specific steps of S2 are as follows: S201: Control the spatial orientation of the implant head so that the implant head reaches the designated position and posture; S202: Control the implant head to descend so that the hollow thin-walled steel needle (4) of the implant head and the continuous Z-pin (1) pierce the composite material structure (5) together; S203: When S202 is performed, the roller group (2) of the implant head locks the continuous Z-pin (1) so that the relative position of the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remains unchanged; S204: Control the implant head to rise so that the front end of the hollow thin-walled steel needle (4) of the implant head and the continuous Z-pin (1) together retract into the interior of the composite material structure (5); S205: When S204 is performed, the roller group (2) of the implant head locks the continuous Z-pin (1) so that the relative position of the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remains unchanged.

3. The protected pre-drilled hole Z-pin implantation method according to claim 1, characterized in that, The specific steps of S5 are as follows: S501: Control the roller group (2) of the implantation head to rotate, retract the continuous Z-pin (1) exposed at the front end of the hollow thin-walled steel needle (4), so that the front end of the continuous Z-pin (1) is flush with the front end of the hollow thin-walled steel needle (4); S502: Control the roller group (2) of the implantation head to lock, so that the relative position of the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remains unchanged; S503: Control the implantation head to descend, and use the continuous Z-pin (1) and the hollow thin-walled steel needle (4) to push the discrete Z-pin (8) exposed on the surface of the composite material structure (5) into the composite material structure (5).

4. The protected pre-drilled hole Z-pin implantation method according to claim 1, characterized in that, The discrete Z-pin (8) residing in the composite material structure has a length that is a set threshold of the thickness at the implantation location of the composite material structure (5).

Images