On-line creel weft yarn conveying speed control method of carbon fiber multi-axial warp knitting machine

Abstract

The invention discloses an online creel weft yarn conveying speed control method of a carbon fiber multi-axial warp knitting machine, and belongs to the technical field of carbon fiber multi-axial warp knitting. The carbon fiber multi-axial warp knitting machine comprises a main chain installed on a main machine frame, a yarn taking device for pulling a carbon fiber weft yarn piece, a carbon fiber weft yarn shaft and an online yarn frame for bearing the carbon fiber weft yarn shaft. The on-line creel weft yarn conveying speed control method is controlled through the formula (I). The weft yarn sheet output speed V3, the speed V2 at which the weft yarn sheet is pulled to advance by the yarn taking device and the moving speed V4 of the yarn creel are matched with one another, and the synthetic speed of the V2 and the V4, namely the weft yarn sheet speed V3, is kept constant in the whole production process, so that the high-quality multi-axial carbon fiber cloth is produced. According to the method, the use requirement of the multi-axial warp knitting machine in the production of the carbon fiber composite material can be well met, the whole machine can run well and stably, and high-quality laying of the multi-axial cloth is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of carbon fiber multiaxial warp knitting technology, and specifically relates to a method for controlling the online weft yarn conveying speed of a carbon fiber multiaxial warp knitting machine. Background Technology

[0002] In composite material production, multiaxial carbon fiber fabric consists of multiple layers of parallel and straightened carbon fiber yarns, which may also include felt, and then bound together using a warp-knitted structure. Structurally, multiaxial fabrics, due to the presence of multiple layers and binding yarns, fully utilize the properties of parallel lines, improving interlayer performance. Because the weft angle can vary between +45° and -45°, the fabric's tensile, tensile strength, and impact resistance are improved, and its manufacturing process is simpler than that of traditional carbon fiber reinforced composites.

[0003] Multiaxial carbon fiber cloth is widely used in wind turbine blades, aerospace, automobile manufacturing, shipbuilding, aircraft components, medicine, sports and leisure and other fields.

[0004] The production of multiaxial carbon fiber fabric requires a multiaxial warp knitting machine. The weft yarn conveying speed on the online yarn creel is an important parameter in the production of multiaxial carbon fiber fabric. If the weft yarn conveying speed on the online yarn creel cannot be accurately calculated and controlled, high-quality multiaxial carbon fiber fabric cannot be produced, and the entire machine may even fail to operate.

[0005] In the production of multiaxial carbon fiber fabric, the carbon fiber precursor bundle must be expanded to a certain width by a yarn spreading device to meet process requirements such as weight. The speed at which the carbon fiber precursor bundle passes through the spreading device, i.e., the weft speed, is highly sensitive to the expansion width. Even slight changes in the weft speed result in different expansion widths, causing the weft width to deviate from the set value. This leads to overlapping or gaps on the fabric surface, resulting in substandard multiaxial carbon fiber fabric. Therefore, precise control of the weft conveying speed on the online yarn crease of the multiaxial warp knitting machine is crucial for producing high-quality multiaxial carbon fiber fabric. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a new method for controlling the weft yarn conveying speed of the online yarn frame of a multiaxial warp knitting machine, so as to keep the speed of the weft yarn constant and ensure the production of high-quality multiaxial carbon fiber fabric.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The present invention is a method for controlling the weft conveying speed of an online yarn frame in a carbon fiber multiaxial warp knitting machine. The carbon fiber multiaxial warp knitting machine includes a main chain (1) installed on the main frame, a yarn taker (2) for pulling the weft yarn sheet (3), and a pressing device (4) for pressing the weft yarn sheet after the yarn taker (2) pulls the weft yarn sheet (3) to the position; it also includes a yarn spreading device (5), a carbon fiber yarn beam (6), and an online yarn frame (7) that carries the yarn spreading device (5) and the carbon fiber yarn beam (6); The weft yarn conveying speed control method on the online yarn frame (7) is as follows: (I)

[0008] (I) In formula (I): V3 is the output speed of the weft yarn strip (3); it refers to the output speed of the weft yarn strip (3) relative to the yarn spreading device (5); V1 is the main chain speed; L1 is the width of the weft yarn piece (3); L2 is the stroke of the yarn take-up device (2); a is the laying angle of the weft yarn piece (3); V2 is the speed at which the yarn take-up device pulls the weft yarn sheet forward; V4 is the online yarn frame moving speed, which refers to the forward and backward movement speed of the entire online yarn frame, including the yarn spreading device 5, the carbon fiber yarn beam 6, and the online yarn frame 7 that carries the yarn spreading device 5 and the carbon fiber yarn beam 6. This speed has two directions: forward or backward. V1, L1, L2, and angle a are all set in advance according to the process requirements.

[0009] The above-described method for controlling the weft yarn conveying speed of a multi-axial warp knitting machine on the online yarn frame is further preferred in the following technical solution: V3, V2, and V4 cooperate with each other, and the combined speed of V2 and V4, i.e., the weft yarn speed V3, remains constant throughout the entire production process, i.e., V3 = V2 + V4.

[0010] The preferred technical solution of the above-described method for controlling the weft conveying speed of the online yarn frame of a multiaxial warp knitting machine for carbon fiber is that the angle range of the laying angle α of the weft yarn sheet (3) is +45° to -45°.

[0011] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes the main chain speed, the width of the weft yarn sheet, the stroke of the yarn take-up device, and the weft yarn laying angle α to calculate and control the speed V3 of the weft yarn sheet, thus achieving speed control of the weft yarn sheet. Furthermore, this invention can also adjust the weft yarn sheet pulling speed V2 and the online yarn creel moving speed V4 based on the weft yarn sheet speed V3, ensuring that the weft yarn sheet speed V3 remains constant throughout the entire production process. This greatly guarantees the laying efficiency and quality of the weft yarn sheet, further improving the quality of the multiaxial carbon fiber cloth. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the control structure of the method of the present invention; Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure; In the diagram: 1-Main chain, 2-Yarn take-up device, 3-Weft yarn plate, 4-Pressure device, 5-Yarn spreading device, 6-Carbon fiber yarn beam, 7-Online yarn frame. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, so as to enable those skilled in the art to understand the present invention, without constituting a limitation on the rights of the present invention.

[0014] Reference Figure 1 and Figure 2 A method for controlling the weft yarn conveying speed of an online yarn frame in a carbon fiber multiaxial warp knitting machine. The carbon fiber multiaxial warp knitting machine involved in the method includes a main chain 1 installed on the main frame, a yarn taker 2 that pulls the weft yarn sheet 3, a pressing device 4 that presses the weft yarn sheet after the yarn taker 2 pulls the weft yarn sheet 3 to the position, a yarn spreading device 5, a carbon fiber yarn beam 6, and an online yarn frame 7 that carries the yarn spreading device 5 and the carbon fiber yarn beam 6.

[0015] The control method is as follows: Let V1 be the main chain speed, V2 be the speed at which the yarn takeer 2 pulls the weft yarn sheet 3, V3 be the weft yarn sheet speed, V4 be the online yarn frame moving speed, L1 be the width of the weft yarn sheet 3, L2 be the stroke of the yarn takeer 2, and a be the weft yarn laying angle. The weft yarn sheet speed V3 refers to the speed of the weft yarn sheet 3 relative to the yarn spreading device 5. The online yarn frame moving speed V4 refers to the forward and backward movement speed of the entire online yarn frame, including the yarn spreading device 5, the carbon fiber yarn beam 6, and the online yarn frame 7 that carries the yarn spreading device 5 and the carbon fiber yarn beam 6. Note that this speed has two directions: forward or backward.

[0016] The main chain speed V1, the width L1 of the weft yarn strip 3, the stroke L2 of the yarn take-up device 2, and the weft yarn laying angle α are all pre-set according to the process and do not require calculation. The weft yarn speed V3 can be calculated using the following formula (I):

[0017] Formula (I) Then, the speeds of the yarn take-up device (V2) and the online yarn frame (V4) are controlled to work together to ensure that the combined speed of these two speeds, i.e., the weft yarn speed (V3), remains constant throughout the entire production process. This calculation method can well meet the requirements of multi-axial warp knitting machines in carbon fiber composite material production, ensuring smooth and stable operation of the entire machine and guaranteeing high-quality laying of multi-axial fabric.

[0018] Below are specific experimental data: Taking the width L1 of weft yarn 3 as 0.5, 0.3, and 0.7 as examples, the calculated weft yarn speed V3 is as follows: name Product 1 Product 2 Product 3 Main chain speed V1 (m / h) 10 12 15 Yarn width L1 (m) 0.5 0.3 0.7 Yarn take-up travel L2 (m) 2.5 2.5 2.5 Weft yarn laying angle a (°) 45 45 60 Weft speed v3 (m / h) 70.71 35.355 26.78 V2 55 -36 20 V4 15.71 0.645 6.78 Fabric quality Excellent, no gaps larger than 0.2mm Excellent, no gaps larger than 0.2mm Excellent, no gaps larger than 0.2mm Based on the calculated weft yarn speed V3, the speed of the yarn take-up device V2 and the moving speed of the online yarn frame V4 are controlled. The two work together to keep the combined speed of the two speeds, i.e., the weft yarn speed V3, constant throughout the entire production process, i.e., V2 + V4 = V3, thereby producing high-quality multiaxial carbon fiber cloth.

[0019] The control method described in this invention can well meet the requirements of multi-axial warp knitting machines in the production of carbon fiber composite materials, ensuring smooth and stable operation of the whole machine and guaranteeing high-quality laying of multi-axial fabric.

[0020] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for controlling the weft yarn conveying speed on the online yarn frame of a carbon fiber multi-axial warp knitting machine, characterized in that, The carbon fiber multiaxial warp knitting machine includes a main chain (1) mounted on the main frame, a yarn taker (2) that pulls the weft yarn sheet (3), and a pressing device (4) that presses the weft yarn sheet (3) after the yarn taker (2) pulls it to the position; it also includes a yarn spreading device (5), a carbon fiber yarn beam (6), and an online yarn frame (7) that carries the yarn spreading device (5) and the carbon fiber yarn beam (6). The weft yarn conveying speed control method on the online yarn frame (7) is as follows: (I) ； (I) In formula (I): V3 is the output speed of the weft yarn strip (3); it refers to the output speed of the weft yarn strip (3) relative to the yarn spreading device (5); V1 is the main chain speed; L1 is the width of the weft yarn piece (3); L2 is the stroke of the yarn take-up device (2); a is the laying angle of the weft yarn piece (3); V2 is the speed at which the yarn take-up device pulls the weft yarn sheet forward; V4 is the online yarn frame moving speed, which refers to the forward and backward movement speed of the entire online yarn frame, including the yarn spreading device 5, the carbon fiber yarn beam 6, and the online yarn frame 7 that carries the yarn spreading device 5 and the carbon fiber yarn beam 6. This speed has two directions: forward or backward. V1, L1, L2, and angle a are all set in advance according to the process requirements; V3, V2, and V4 work together, and the combined speed of V2 and V4, i.e., the weft speed V3, remains constant throughout the entire production process, i.e.: V3 = V2 + V4.

2. The method for controlling the weft yarn conveying speed of a multi-axial warp knitting machine on an online yarn crease as described in claim 1, characterized in that, The angle range of the weft yarn sheet (3) laying angle a is: +45° to -45°.

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