Laying and winding in-situ forming method for thermoplastic composite gas cylinder

Abstract

The invention discloses a thermoplastic composite material gas cylinder laying and winding in-situ forming method. The method comprises the following steps: setting related parameters; according to the size of a gas cylinder model, a proper laying and winding CAM path program is selected and guided into a laying and winding integrated in-situ forming prototype; carrying out sand blasting treatment on the outer surface of the metal inner container of the gas cylinder; the gas cylinder metal inner container obtained after sand blasting is clamped on a horizontal rotary table, and the surface of the gas cylinder metal inner container is coated with an adhesive; installing the thermoplastic prepreg tape in a yarn hanging area, heating the thermoplastic prepreg tape by using laser heating equipment according to the laying and winding CAM path program until the thermoplastic prepreg tape is molten, and then starting laying and winding; and after laying and winding are completed, yarn breaking is conducted, after the outer laying and winding layer of the metal inner container of the gas cylinder is cooled to the room temperature, the thermoplastic composite material gas cylinder tool is disassembled, and the needed composite material gas cylinder is obtained. According to the method, theoretical calculation parameters are set according to a plastic composite unidirectional laminate mechanical property test, an NOL ring performance test and a preliminary test mechanical property test, so that the quality stability of the composite gas cylinder is improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite material gas cylinder forming technology, and in particular to a thermoplastic composite material gas cylinder lay-up in-situ forming method. Background Art

[0002] At present, most existing composite gas cylinders adopt a three-layer structure of an inner single layer, a winding layer and an outer protective layer. The winding layer generally uses a carbon fiber impregnated thermosetting resin system to wet-wind the composite layer, and finally enters the curing furnace for curing and molding. However, the curing molding method will cause gaps and overlaps between the upper and lower prepregs due to uneven width and thickness of the prepreg, which ultimately leads to low precision and quality of the product. In addition, the use of a curing furnace will release harmful substances and pollute the environment.

[0003] High-strength and high-toughness thermoplastic polymer materials such as polyetheretherketone have better mechanical properties, temperature resistance and creep resistance than existing thermosetting resins, and are the research target materials for breakthroughs in the performance of existing composite gas cylinders. The principle of the automatic placement in-situ molding technology of continuous fiber reinforced thermoplastic composites is to position, lay and quickly solidify the wires according to the requirements of the digital winding line shape through a wire laying device with a special heating device, and accumulate layer by layer in the thickness direction of the mold to complete the process of part manufacturing when the designed thickness is reached. However, there is no relevant introduction to the combination of thermoplastic composites and in-situ molding technology in the existing technology.

[0004] Therefore, it is urgent to propose a new method to solve the above problems. Summary of the invention

[0005] The present invention provides a thermoplastic composite material gas cylinder lay-up in-situ forming method, which adopts a method combining thermoplastic composite material with lay-up in-situ forming to solve the problem of gap and overlap between upper and lower prepreg tapes caused by uneven width and thickness of prepreg tapes in existing curing and forming methods, thereby improving the precision and quality of products.

[0006] The present invention provides a thermoplastic composite material gas cylinder lay-up in-situ forming method, which is special in that it comprises the following steps:

[0007] 1) According to the bursting pressure of the gas cylinder, the required number of layers of thermoplastic prepreg is obtained, and the theoretical calculation parameters are set according to the mechanical properties test of the unidirectional laminate of plastic composite materials, the NOL ring performance test and the mechanical properties test of the bottom test;

[0008] 2) According to the size of the gas cylinder model, select a suitable laying and wrapping CAM path program, and import the laying and wrapping CAM path program into the laying and wrapping integrated in-situ molding prototype;

[0009] 3) Sandblast the outer surface of the metal liner of the gas cylinder;

[0010] 4) Clamp the metal liner of the gas cylinder after sand blowing on the horizontal rotary table and apply adhesive on the surface;

[0011] 5) Install the thermoplastic prepreg tape in the yarn hanging area, take the mouth or bottom of the gas cylinder as the starting point, set the safe distance between the laying and wrapping head and the cylinder section, and then heat the thermoplastic prepreg tape to melt using a laser heating device according to the laying and wrapping CAM path program before starting the laying and wrapping;

[0012] 6) After the laying and winding is completed, the yarn is cut off, and after the laying and winding layer outside the metal liner of the gas cylinder drops to room temperature, the thermoplastic composite gas cylinder tooling is disassembled to obtain the required composite gas cylinder.

[0013] Furthermore, in the step 1), the parameters include initial tension, roller pressure, laser power and fiber strength utilization rate.

[0014] Furthermore, in the step 1), the initial tension is set to 80-120N, the pressure of the pressure roller is set to 280-320N, the laser power is set to 680-720W, and the fiber strength utilization rate is 83-88%.

[0015] Furthermore, in the step 1), the initial tension is set to 100N / strand, and decreases by 1N after each two layers are laid.

[0016] Furthermore, in the step 1), the number of winding layers required to reach the bursting pressure of the gas cylinder is calculated by a grid structure fiber winding method.

[0017] Furthermore, in the step 4), the adhesive is heated at 40° C. to 60° C. for 0.5 h to 2 h, and a layer is evenly applied on the outer surface of the metal liner of the gas cylinder using a brush, and then left to air for at least 30 min.

[0018] Furthermore, in the step 5), the safety distance is set to a value of 30 to 50 mm.

[0019] Furthermore, in the step 5), the process of laying and winding is that spiral winding and hoop winding are performed alternately in sequence, and the winding angle is set to 9.0-9.5°.

[0020] Furthermore, the step 6) further includes performing a water pressure test and a burst test on the molded thermoplastic composite gas cylinder, wherein the pressure of the water pressure test is not less than 10 MPa, and the pressure of the burst test is not less than 16.5 MPa.

[0021] Furthermore, in the step 3), the outer surface of the metal liner of the gas cylinder is subjected to sand blasting treatment, the sand blasting pressure is 0.18-0.22 MPa, and the mesh number of the yarn is 38-42 meshes.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention sets theoretical calculation parameters according to the mechanical property test of the unidirectional laminate of plastic composite materials, the performance test of the NOL ring and the mechanical property test of the bottom test. The unidirectional plate and the NOL ring laid out by coupling these parameters have the best mechanical properties. The thermoplastic composite material is used to convert the performance of the matrix resin into the improvement of the mechanical properties of the composite gas cylinder, and the heat resistance and aging resistance are improved. At the same time, the quality stability of the composite gas cylinder is improved and the design and manufacturing constraints are reduced;

[0024] 2. The present invention uses laser heating equipment to heat and cure layer by layer, ensuring that each layer of prepreg is evenly heated and quickly cured, avoiding the gap and overlap problems caused by uneven width and thickness of the prepreg in traditional methods, so that the final composite material gas cylinder has higher dimensional accuracy and quality consistency, and no longer needs to use a curing furnace or autoclave for curing, which greatly simplifies the manufacturing process and curing cost. In addition, the production process has little impact on the environment and does not release harmful substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the in-situ forming and curing process of the thermoplastic composite material gas cylinder of the present invention;

[0026] Figure numerals: laser head 1; thermoplastic prepreg tape 2; pressure roller 3; metal liner of gas cylinder 4; composite material substrate 5; bonding point 6. DETAILED DESCRIPTION

[0027] In order to further understand the content, features and effects of the present invention, the following embodiments are given together with the attached Figure 1 The detailed instructions are as follows.

[0028] The present invention provides a thermoplastic composite material gas cylinder lay-up in-situ forming method, comprising the following steps:

[0029] 1) According to the bursting pressure of the gas cylinder, the required number of layers of thermoplastic prepreg is obtained, and the mechanical properties test of the unidirectional laminate of the plastic composite material, the NOL ring performance test and the bottom test mechanical properties test are carried out to set the theoretical calculation parameters; the metal liner of the gas cylinder adopts the spinning molding process, the diameter is Φ394mm, the total length of the gas cylinder is 445.6mm, and the bursting pressure is ≥14MPa.

[0030] Among them, according to the four standards of GB / T3354-2014 tensile properties test method for oriented fiber reinforced polymer matrix composites, GB / T3356-2014 flexural properties test method for oriented fiber reinforced polymer matrix composites, GBT3856-2005 unidirectional fiber reinforced plastic flat plate compression performance test method and JC / T773-2010 fiber reinforced short beam method for determining interlaminar shear strength, the mechanical properties test of thermoplastic composite unidirectional laminates was carried out. According to GB / T1458-2023 mechanical properties test method for fiber winding reinforced plastic ring specimens, the NOL ring performance test of thermoplastic composites was carried out to understand the mechanical properties parameters of the test plate and set the relevant theoretical calculation parameters.

[0031] In this embodiment, the parameters include initial tension, roller pressure, laser power and fiber strength utilization rate, wherein the initial tension is set to 100N, and its value can also be other values ​​between 80 and 120N, the roller pressure is set to 300N, and its value can also be other values ​​between 280 and 320N, and the laser power is set to 700W, and its value can also be other values ​​between 680 and 720W. In addition, in order to ensure the process safety margin, the theoretical calculation of the fiber strength utilization rate is taken as 85%, and other values ​​between 83 and 88% can also be taken. The stress balance coefficient is taken as 0.75, and a pressure test is carried out on a small gas cylinder with a diameter of 50mm and a length of 100mm. The process parameters are adjusted according to the test results; finally, the process design is carried out according to the required pressure of the product gas cylinder, and a pressure test is carried out. ;

[0032] 2) According to the size of the gas cylinder model, in this embodiment, according to the gas cylinder model parameters such as the front and rear opening diameters of Φ15mm, the front head height of 102.8mm, the rear head height of 88.8mm, the winding angle of 9.3°, and the barrel length of 254mm, the spiral laying and wrapping CAM path program of the gas cylinder generated based on the CADWIND simulation line shape is selected, and the laying and wrapping CAM path program is imported into the laying and wrapping integrated in-situ molding prototype;

[0033] 3) Sandblast the outer surface of the metal liner of the gas cylinder to improve the surface bonding strength;

[0034] 4) Clamp the metal liner of the gas cylinder after sand blowing on the horizontal rotary table and apply adhesive on the surface;

[0035] 5) Install a 6.35 mm wide thermoplastic prepreg tape in the yarn hanging area. The width of the thermoplastic prepreg tape can also be selected as other values ​​according to actual needs. The width of the thermoplastic prepreg tape of the present invention is 6.35 mm. Other sizes can also be selected according to actual needs. The mouth or bottom of the gas cylinder is used as the starting point for winding. After setting the safe distance between the laying and wrapping head and the cylinder section, according to the laying and wrapping CAM path program, use a laser heating device to heat the thermoplastic prepreg tape until it is melted and then start laying and wrapping;

[0036] 6) After the winding is completed, the yarn is cut off, the robot power and laser power are turned off, and the site is cleaned up in accordance with the 6S requirements. After the winding layer outside the metal liner of the gas cylinder drops to room temperature, the thermoplastic composite gas cylinder tooling is disassembled to obtain the required composite gas cylinder.

[0037] The present invention sets theoretical calculation parameters according to mechanical property tests of unidirectional laminates of plastic composite materials, performance tests of NOL rings and mechanical property tests of baseline tests. The unidirectional plates and NOL rings laid out by coupling these parameters have optimal mechanical properties. The thermoplastic composite materials are used to convert the performance of the matrix resin into the improvement of the mechanical properties of the composite gas cylinder, and the heat resistance and aging resistance are improved. At the same time, the quality stability of the composite gas cylinder is improved and the design and manufacturing constraints are reduced. In addition, the present invention uses laser heating equipment to heat and cure layer by layer to ensure that each layer of prepreg is evenly heated and quickly cured, avoiding the gap and overlap problems caused by uneven width and thickness of the prepreg in the traditional method, so that the size accuracy and quality consistency of the final composite gas cylinder are higher, and there is no need to use a curing furnace or an autoclave for curing, which greatly simplifies the manufacturing process and curing cost, and has little impact on the environment during the production process and does not release harmful substances.

[0038] In this embodiment, after the yarn is broken, the weight of the remaining prepreg used for laying and winding is counted, and the actual amount of prepreg used is counted and compared with the theoretical amount. The final deviation is within 1%, thereby confirming the rationality of the method of the present invention.

[0039] In this embodiment, the initial tension is set to 100N / strand, and decreases by 1N after each two layers are laid.

[0040] In this embodiment, the number of layers required to reach the bursting pressure of the gas cylinder is calculated by the grid structure fiber winding method. The calculated winding layer thickness is 2.63 mm, including 8 layers of spiral winding and 7 layers of circumferential winding. The weight of the winding layer is 1.1 kg.

[0041] In this embodiment, the HPI adhesive is heated at 50°C for 1 hour, the temperature may also be other values ​​between 40°C and 60°C, the heating time may be other values ​​between 0.5h and 2h, and a layer (70g / m2) is evenly applied on the outer surface of the metal liner of the gas cylinder using a brush. 2 ), and leave it in the air for at least 30 minutes to ensure that all the solvent in the adhesive evaporates.

[0042] In this embodiment, the safety distance is set to 40 mm, and may also be other values ​​between 30 and 50 mm to ensure safety during processing.

[0043] In this embodiment, the process of laying and winding is that spiral winding and hoop winding are performed alternately in sequence, and the winding angle is set to 9.3°. Other values ​​between 9.0 and 9.5° can also be selected according to actual needs.

[0044] In this embodiment, after step 6), it also includes conducting a water pressure test and a burst test on the formed thermoplastic composite gas cylinder, the pressure of the water pressure test is not less than 10MPa, and the pressure of the burst test is not less than 16.5Mpa. The thermoplastic composite gas cylinder formed by the present invention has good strength uniformity, the pressure of the water pressure test is 10MPa, the burst pressure is 16.5MPa, and the fiber strength utilization rate reaches 92%, which is greater than the previously set theoretical value of 85%, and can fully meet the gas cylinder winding strength requirements. Fiber strength utilization rate is one of the key indicators for evaluating the performance of composite materials. Fiber strength utilization rate = actual stress of the fiber in the composite material / maximum stress that the fiber can withstand in a unidirectional tensile test, and its value is between 0 and 1. In the preparation process of high-performance composite pressure vessels, fiber strength utilization rate is a crucial parameter. In this embodiment, the fiber strength utilization rate reaches 92%, proving that the final laying and winding effect is very good.

[0045] In this embodiment, when the outer surface of the metal inner liner of the gas cylinder is sandblasted, the sandblasting pressure is 0.20 MPa, and the mesh number of the yarn is 40 meshes. The sandblasting pressure can also be other values ​​between 0.18 and 0.22 MPa, and the mesh number of the yarn can be other values ​​between 38 and 42 meshes.

[0046] like Figure 1 The figure shows a schematic diagram of the in-situ forming and curing process of the thermoplastic composite gas cylinder of the present invention. The thermoplastic prepreg tape 2 is conveyed to the bottom of the pressure roller 3 by the conveying device. The outer surface of the metal inner liner 4 of the gas cylinder is wrapped with multiple layers of thermoplastic prepreg tapes 2. The thermoplastic prepreg tapes 2 are heated by radiation from the laser head 1. The high-intensity laser heat source directly radiates at the bonding point 6 of the prepreg and the composite substrate 5, and a melting zone is formed near the bonding point 6.

[0047] The above invention only expresses the implementation method of the embodiment of the present invention, and cannot be understood as limiting the scope of the invention patent, nor does it impose any form of limitation on the structure of the embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several changes and improvements can be made without departing from the concept of the embodiment of the present invention, which all belong to the protection scope of the embodiment of the present invention.

Claims

1. A thermoplastic composite material gas cylinder lay-up in-situ forming method, characterized in that: The following steps are involved: 1) According to the bursting pressure of the gas cylinder, the required number of layers of thermoplastic prepreg is obtained, and the theoretical calculation parameters are set according to the mechanical properties test of the unidirectional laminate of plastic composite materials, the NOL ring performance test and the mechanical properties test of the bottom test; 2) According to the size of the gas cylinder model, select a suitable laying and wrapping CAM path program, and import the laying and wrapping CAM path program into the laying and wrapping integrated in-situ molding prototype; 3) Sandblast the outer surface of the metal liner of the gas cylinder; 4) Clamp the metal liner of the gas cylinder after sand blowing on the horizontal rotary table and apply adhesive on the surface; 5) Install the thermoplastic prepreg tape in the yarn hanging area, take the mouth or bottom of the gas cylinder as the starting point, set the safe distance between the laying and wrapping head and the cylinder section, and then heat the thermoplastic prepreg tape to melt using a laser heating device according to the laying and wrapping CAM path program before starting the laying and wrapping; 6) After the laying and winding is completed, the yarn is cut off, and after the laying and winding layer outside the metal liner of the gas cylinder drops to room temperature, the thermoplastic composite gas cylinder tooling is disassembled to obtain the required composite gas cylinder.

2. The in-situ forming method for thermoplastic composite gas cylinder lay-up according to claim 1, characterized in that: In the step 1), the parameters include initial tension, roller pressure, laser power and fiber strength utilization rate.

3. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 2, characterized in that: In the step 1), the initial tension is set to 80-120N, the pressure of the pressure roller is set to 280-320N, the laser power is set to 680-720W, and the fiber strength utilization rate is 83-88%.

4. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 3, characterized in that: In the step 1), the initial tension is set to 100 N / strand, and is decreased by 1 N after each two layers are laid.

5. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 1, characterized in that: In the step 1), the number of winding layers required to achieve the bursting pressure of the gas cylinder is calculated by a grid structure fiber winding method.

6. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 1, characterized in that: In the step 4), the adhesive is heated at 40° C. to 60° C. for 0.5 h to 2 h, and a layer is evenly applied on the outer surface of the metal liner of the gas cylinder using a brush, and then left to air for at least 30 min.

7. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 1, characterized in that: In the step 5), the safety distance is set to a value of 30 to 50 mm.

8. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 1, characterized in that: In the step 5), the process of laying and winding is that spiral winding and hoop winding are performed alternately in sequence, and the winding angle is set to 9.0-9.5°.

9. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 1, characterized in that: The step 6) further includes performing a water pressure test and a burst test on the formed thermoplastic composite gas cylinder, wherein the pressure of the water pressure test is not less than 10 MPa, and the pressure of the burst test is not less than 16.5 MPa.

10. The thermoplastic composite material gas cylinder lay-up in-situ forming method according to claim 1, characterized in that: In the step 3), the outer surface of the metal liner of the gas cylinder is subjected to sand blasting treatment, the sand blasting pressure is 0.18-0.22 MPa, and the mesh number of the yarn is 38-42 meshes.

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