Carbon fiber composite material manufacturing process and medical device housings

Abstract

The present disclosure provides a carbon fiber composite material preparation process and a medical device shell produced by the preparation process. The carbon fiber composite material preparation process includes preparing a carbon fiber cloth, including determining the number of layers of the carbon fiber cloth according to the shielding efficiency of the workpiece, and cutting the carbon fiber cloth according to the workpiece drawing; preparing auxiliary materials, calculating the weight of the auxiliary materials according to the size of the workpiece, the auxiliary materials including thermosetting resin and / or thermoplastic resin, or the auxiliary materials including thermoplastic plastic; workpiece forming, heating the mold to a first preset temperature, placing the prepared carbon fiber cloth in the mold according to the positioning, and forming the prepared carbon fiber cloth and the prepared auxiliary materials together; the electrical conductivity of the workpiece obtained after forming is not less than 1.0X 10 3 S / ㎝. The present disclosure can combine the high strength and electrical conductivity of carbon fiber materials with the better flow of resin and other materials, making carbon fiber products diverse in design and improving production efficiency.

Description

Technical Field

[0001] This disclosure relates to carbon fiber composite material technology, and more specifically, to a process for preparing a carbon fiber composite material and a housing for a medical device obtained using the process. Background Technology

[0002] Currently, to effectively suppress electromagnetic interference (EMI) inside or outside the equipment, medical devices are mostly made of metal. Metal materials are heavy and bulky, making them unsuitable for movement or portability. Shells made of plastic or fiberglass have poor strength and radiation resistance. To achieve EMI suppression, these materials are often electroplated or coated with conductive paint. However, electroplating can alter the mechanical properties of the substrate, and conductive paint coating often results in uneven application, leading to poor EMI shielding and EMI suppression performance, or paint peeling. Furthermore, the use of these materials can hinder product sealing design due to their modular structure.

[0003] Carbon fiber materials exhibit good performance in terms of strength, weight, and electromagnetic shielding, but they are expensive, have complex processes, long production cycles, and lack plasticity. Therefore, carbon fiber composite products are difficult to mass-produce. Summary of the Invention

[0004] This disclosure provides a process for preparing carbon fiber composite materials and a medical device housing obtained by the process, in order to solve one or more of the above-mentioned technical problems.

[0005] According to a first aspect of this disclosure, a process for preparing carbon fiber composite materials is provided, comprising: preparing carbon fiber cloth, including determining the number of layers of carbon fiber cloth according to the shielding effectiveness of the workpiece, and cutting the carbon fiber cloth according to the unfolded diagram of the workpiece; preparing auxiliary materials, calculating the weight of the auxiliary materials according to the dimensions of the workpiece, wherein the auxiliary materials include thermosetting resin and / or thermoplastic resin or the auxiliary materials include thermoplastic plastic; forming the workpiece, heating the mold to a first preset temperature, placing the prepared carbon fiber cloth in the mold according to the positioning, and forming the prepared carbon fiber cloth and the prepared auxiliary materials together; the electrical conductivity of the workpiece obtained after forming is not less than 1.0 x 10⁻⁶. 3 S / ㎝.

[0006] Optionally, according to a first aspect of this disclosure, preparing carbon fiber cloth further includes heating the mold to a second predetermined temperature; placing the carbon fiber cloth in the mold in a position; and molding the carbon fiber cloth into a blank for use as the prepared carbon fiber cloth.

[0007] Optionally, according to a first aspect of this disclosure, the second predetermined temperature is about 140 degrees to about 180 degrees, and the molding time of the preform is about 40 seconds to about 120 seconds. Optionally, the molding time of the preform is about 40 seconds to 65 seconds.

[0008] By pre-forming the carbon fiber cloth, the subsequent workpieces can be formed with higher precision.

[0009] In the embodiments of this disclosure, the forming time of the workpiece can be controlled within approximately 2 minutes, thereby achieving higher production efficiency.

[0010] Optionally, according to a first aspect of this disclosure, when the auxiliary material comprises a thermosetting resin, the first predetermined temperature is about 100 degrees to about 190 degrees, the molding time of the workpiece is about 40 seconds to about 120 seconds, and the molding pressure of the workpiece is about 80 MPa to about 100 MPa; when the auxiliary material comprises a thermoplastic, the first predetermined temperature is determined based on the glass transition temperature of the thermoplastic, the molding time of the workpiece is about 40 seconds to about 120 seconds, and the molding pressure of the workpiece is about 80 MPa to about 100 MPa.

[0011] Optionally, according to a first aspect of this disclosure, the auxiliary material includes epoxy resin or vinyl resin, chopped reinforcing fibers and additives, wherein when the chopped reinforcing fibers are glass fibers, they account for 20%-35% of the weight of the auxiliary material, and when the chopped reinforcing fibers are carbon fibers, they account for 30%-60% of the weight of the auxiliary material.

[0012] Optionally, according to a first aspect of this disclosure, the preparation of auxiliary materials includes: mixing epoxy resin or vinyl resin and additives evenly to form a mixture; applying the mixture to the inner side of two layers of polyethylene film respectively; depositing short-cut reinforcing fibers on the lower polyethylene film; stacking and rolling the upper and lower polyethylene films into a sheet; curing the sheet material; and cutting the sheet material according to the unfolded drawing of the workpiece as the prepared auxiliary material.

[0013] Sheet materials made from thermosetting resin blends offer possibilities for complex product shapes and structures. Adding reinforcing fibers can help increase workpiece strength. Furthermore, when using chopped carbon fibers as reinforcing fibers, a higher carbon fiber content not only contributes to increased strength but also enhances electromagnetic shielding.

[0014] Optionally, according to a first aspect of this disclosure, the auxiliary materials include epoxy resin or vinyl resin, inorganic fillers and additives, wherein the weight of the inorganic fillers is not less than the weight of the resin.

[0015] Optionally, according to a first aspect of this disclosure, the preparation of the auxiliary material includes uniformly mixing epoxy resin or vinyl resin, additives, and inorganic fillers; covering both sides of the mixture with polyethylene film and rolling it into a sheet; curing the sheet material by drying; and cutting it according to the unfolded drawing of the workpiece as the prepared auxiliary material.

[0016] Optionally, according to a first aspect of this disclosure, the auxiliary material comprises an ABS / PC alloy material, and the step of preparing the auxiliary material includes drying the ABS / PC alloy material at about 100 degrees Celsius.

[0017] This disclosure describes a process where carbon fiber cloth and auxiliary materials are processed separately before being molded together. This allows for the integral molding of carbon fiber with other composite materials, ensuring the quality and precision of the molded workpiece. The resulting workpiece combines the high strength and conductivity of carbon fiber with the good flowability of materials such as resin, resulting in diverse carbon fiber product designs. Simultaneously, it improves the production efficiency of carbon fiber product manufacturing.

[0018] According to a second aspect of this disclosure, a housing for a medical device is provided, comprising a carbon fiber composite material manufactured using the aforementioned carbon fiber composite material preparation process, wherein the electrical conductivity of the carbon fiber composite material is not less than 10. 3 S / cm, the workpiece strength is not less than 2.0 GPa. Optionally, the electromagnetic shielding effectiveness of the carbon fiber composite workpiece is not less than 60dB in the 10KHz-18GHz range.

[0019] The housing for medical devices manufactured according to the carbon fiber composite material preparation process disclosed herein can be used in various scenarios, especially in environments with high requirements for electromagnetic shielding, such as military medical devices and life support integrated machines suitable for multiple scenarios.

[0020] Implementing any apparatus of this disclosure does not necessarily require achieving all of the advantages described above simultaneously. Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description and embodiments, or may be learned by practicing this disclosure. The objects and advantages of embodiments of this disclosure may be realized and obtained by means of the structures pointed out in the description and claims. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below in conjunction with the embodiments of this disclosure. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Various different embodiments can be combined with each other to constitute other embodiments not shown in the following description. Based on the described embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0022] In this disclosure, unless otherwise expressly stated, the use of the singular includes the plural and the plural includes the singular. For example, although “one” resin is referred to herein, one or more of the same substance may be used.

[0023] In this disclosure, the terms “comprising,” “including,” and “containing,” etc., are not intended to limit this disclosure or exclude any variations or additions. It should be understood that any numerical range listed herein is intended to include all subranges contained therein. For example, the range “1 to 10” is intended to include all subranges between the listed minimum value 1 and the listed maximum value 10 (inclusive), i.e., all subranges having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. The ranges and endpoints of any values ​​disclosed herein are not limited to precise ranges or values; they are sufficiently imprecise to include values ​​close to these ranges and / or values.

[0024] Except as expressly stated in the embodiments or otherwise, it should be considered that the numerical values ​​of all representative components, process data, etc., used in the specification and claims are all subject to variation in all cases according to the term "about". Therefore, unless stated to the contrary, the numerical parameters listed in the following specification and claims are approximate values ​​and may vary according to the performance desired by this disclosure.

[0025] According to one aspect of this disclosure, the raw materials for carbon fiber composites may include one or more layers of carbon fiber cloth, such as 1K, 3K, 5K, 6K, or 12K carbon fiber cloth (carbon content above 90%); auxiliary materials may include thermosetting resins and / or thermoplastic resins, or auxiliary materials may include thermoplastic plastics. Thermosetting resins cannot be repeatedly processed and molded after cross-linking and curing; thermoplastic resins can be repeatedly heated to soften and cooled to cure without intermolecular cross-linking. Thermoplastic plastics are mainly composed of thermoplastic resins, possess plasticity at a certain temperature, cure upon cooling, and this process can be repeated; they do not undergo intermolecular cross-linking when heated.

[0026] Thermosetting resin materials include one or more of the following: epoxy resin, unsaturated resin, polyurethane resin, polyimide resin, urea-formaldehyde resin, and phenolic resin. Thermoplastic resin materials include one or more of the following: polyoxymethylene resin, polyethylene resin, polyvinyl chloride resin, polypropylene resin, polycarbonate resin, and polyacrylic acid resin.

[0027] Thermoplastic materials may include one or more of the following: polyethylene, polyvinyl chloride, polypropylene, polycarbonate, polysulfone, polysulfide, polyether, polyamide, ABS, polyacrylic acid, other polyolefins and their copolymers.

[0028] The process flow for preparing carbon fiber composite materials mainly includes the following steps:

[0029] (1) Prepare the carbon fiber cloth as the main material. The main material is determined based on the shielding performance. For example, one layer of carbon fiber cloth provides approximately 40dB of shielding effectiveness at around 100MHz, two layers provide approximately 65dB, and three layers provide approximately 74dB. The carbon fiber cloth is cut according to the workpiece unfolding requirements, and the thickness of the carbon fiber cloth can also be determined based on performance needs. Using carbon fiber cloth as the main material utilizes the high strength and conductivity of carbon fiber composite materials. Carbon fiber cloth specifications such as 1K, 3K, 5K, 6K, and 12K can be selected.

[0030] The number and thickness of the carbon fiber cloth layup can be determined based on the required shielding wavelength and shielding effectiveness of the workpiece. If there is more than one layer of carbon fiber cloth, the layers can be bonded together.

[0031] Optionally, preparing carbon fiber cloth can also include molding the carbon fiber cloth into a preform. Specifically, the molding press is heated to a preset temperature, for example, between approximately 140 and 180 degrees Celsius (e.g., approximately 150, 160, or 170 degrees Celsius), and the cut carbon fiber cloth is laid up, with more than one layer stacked as needed. The stacked carbon fiber is then placed in the molding press and molded for approximately 40-120 seconds (e.g., approximately 45, 60, 80, or 100 seconds). The pressure range is approximately 6-8 tons per square meter. The preform is then used as the prepared carbon fiber cloth. The process of forming the carbon fiber cloth preform is relatively quick, resulting in high production efficiency and suitability for mass production.

[0032] By molding the carbon fiber cloth as the main material, the strength and electromagnetic shielding effectiveness of the composite material are ensured, and a high-precision blank suitable for secondary molding is also provided for subsequent steps. High precision mainly refers to the fact that the part does not deform after compression molding, and its shape and positioning dimensions are relatively stable.

[0033] (2) Preparing auxiliary materials includes calculating the weight of the auxiliary materials based on the dimensions of the workpiece. For example, calculating the weight of the auxiliary materials based on the area and thickness of the workpiece, and processing the auxiliary materials.

[0034] Optionally, the auxiliary materials may primarily include thermosetting resins, thermoplastic resins, or thermoplastic plastics.

[0035] Treatment of auxiliary materials including thermosetting resins

[0036] In addition to thermosetting resins, auxiliary materials may further include chopped reinforcing fiber materials and additives. Reinforcing fiber materials include, for example, glass fiber and carbon fiber.

[0037] In one embodiment, the auxiliary material may primarily comprise a thermosetting resin and glass fiber, wherein the thermosetting resin may be an epoxy resin, comprising approximately 50% or more of the auxiliary material by weight, for example, 50%-70%, and the glass fiber may comprise approximately 20%-35% of the auxiliary material by weight, for example, about 25% or about 30%. The epoxy resin may be a glycidylamine type epoxy resin, a glycidyl ester type epoxy resin, etc. The glass fiber may be short-cut glass fiber with a length of less than 1 inch (e.g., about 10mm-20mm).

[0038] In another embodiment, the auxiliary material may primarily comprise a thermosetting resin and chopped carbon fibers. The thermosetting resin may be an epoxy resin or a vinyl resin, comprising approximately 30%-60% (e.g., approximately 50%) of the auxiliary material's weight. The chopped carbon fibers may comprise approximately 30%-60% (e.g., approximately 40% or approximately 50%) of the auxiliary material's weight. The epoxy resin may be a glycidylamine type epoxy resin, a glycidyl ester type epoxy resin, etc. The chopped carbon fibers may be chopped carbon fibers with a length of less than 1 inch (e.g., 10mm-20mm).

[0039] In the above embodiments, the additives may include thickeners, release agents, coupling agents, flame retardants, etc. The additives may also include plasticizers, which can improve the product's flexibility and enhance its impact resistance.

[0040] In the above embodiments, the auxiliary material is processed according to the following steps to prepare it into a sheet material: a mixture is prepared using thermosetting resin and additives; the mixture is coated onto the inner side of both upper and lower polyethylene films; short-cut reinforcing fiber material is deposited onto the lower polyethylene film coated with the mixture; the upper and lower polyethylene films are stacked and rolled into a sheet; the sheet material is cured by drying and prepared for later use; the sheet material is cut according to the workpiece unfolding diagram. The drying temperature can be approximately 50°C to approximately 60°C, and the time is approximately 12-24 hours. The viscosity of the mixture at room temperature (around 20°C) is approximately 25 Pa·s to approximately 35 Pa·s, for example, 30 Pa·s. The reinforcing fiber material is deposited as uniformly as possible on the lower polyethylene film.

[0041] Sheet materials made from thermosetting resin blends offer the possibility of complex product shape and structure designs, and reduce the overall weight of the product due to the low density of the resin (approximately 1.0 to approximately 1.2 g / cm³).

[0042] Treatment of auxiliary materials, mainly including thermoplastic resins or thermoplastic plastics.

[0043] When the auxiliary materials mainly consist of thermoplastic plastics (or thermoplastic resins), they need to be dried. The drying temperature is approximately 60-100℃, and the time is approximately 2-5 hours. Drying reduces the moisture content of the materials and improves product quality.

[0044] The above treatments for main materials and auxiliary materials are independent, and the order of treatment can be adjusted according to the actual situation.

[0045] (3) Workpiece forming

[0046] When the auxiliary materials mainly consist of thermosetting resin, the mold is heated to a preset temperature, for example, between approximately 100 and 190 degrees Celsius, or below 180 degrees Celsius, such as 145, 155, or 160 degrees Celsius. The prepared carbon fiber preform and the prepared cut sheet material are stacked and positioned in a molding machine, and the materials are molded for at least 40 seconds. The molding pressure is 80 MPa to 100 MPa. The molding time can be approximately 40 to 120 seconds, for example, approximately 45 seconds, 65 seconds, 80 seconds, 100 seconds, or 120 seconds.

[0047] When the auxiliary materials mainly consist of thermoplastic resin or thermoplastic plastic, the injection molding machine mold is heated to a preset temperature, which is determined based on the glass transition temperature of the material. The preform is then placed in the injection mold according to its positioning for injection molding. The injection time can be approximately 40 seconds to 120 seconds, for example, less than 100 seconds, such as approximately 45 seconds, 70 seconds, or 80 seconds. The injection pressure is 80 MPa to 100 MPa.

[0048] Before the workpiece is formed, the blank can be sandblasted and / or wiped with organic solvents such as acetone (content of about 30%) to improve the bonding ability between the blank and subsequent materials.

[0049] (4) Post-molding treatment

[0050] For parts that cannot be molded as a single unit, the individual parts can be bonded together with resin adhesive to form a whole component. To ensure the conductivity and electromagnetic compatibility of the whole component, prepreg of carbon fiber can be used to reinforce the connecting parts.

[0051] This invention significantly shortens the production cycle through the above method, while simultaneously reducing the workpiece conductivity to approximately 10. 3 With a shielding effectiveness of at least 60dB-90dB in the 10KHz-18GHz range, the workpiece strength is not less than 2.0GPa.

[0052] The following specific examples illustrate the method for manufacturing composite materials:

[0053] Example 1

[0054] (1) The main material is two layers of 0.25 mm thick carbon fiber prepreg. The auxiliary materials include epoxy resin and chopped glass fiber. Based on the total weight of the auxiliary materials, the auxiliary materials include 150 parts of glycidylamine epoxy resin, 120 parts of 15 mm chopped glass fiber, and 20 parts of additives, including thickeners, release agents, coupling agents, plasticizers, curing agents, flame retardants, etc.

[0055] (2) Prepare and process the main material. Cut the carbon fiber prepreg into the desired shape according to the workpiece unfolding diagram, and cut, align and stack the two layers of carbon fiber prepreg together and bond them together.

[0056] (3) Prepare and process the auxiliary materials.

[0057] a. First, mix the epoxy resin with the mold release agent, plasticizer, coupling agent, and flame retardant, and stir evenly for about 10 minutes;

[0058] b. Add the thickener and curing agent evenly, and mix for about 3 minutes until the desired viscosity is reached (e.g., about 25-30 Pa·s);

[0059] c. Apply the mixture prepared above to the inner sides of the upper and lower polyethylene films respectively;

[0060] d. 15 mm chopped glass fibers are uniformly deposited and impregnated on the mixture coated with the lower polyethylene film;

[0061] e. The upper and lower layers are stacked so that the mixture coated on the inner side of the polyethylene film faces the chopped glass fibers, and then rolled into a sheet material;

[0062] f. The sheet material is cured by drying at 50°C for 24 hours. This sheet material is then used as a prepared auxiliary material and cut according to the workpiece unfolding diagram.

[0063] (4) Heat the mold to 145℃-155℃; place the cut carbon fiber prepreg in the mold according to the positioning and stack it with the sheet material; close the mold and press, the pressure is about 8 tons / square meter, and the time is about 40-65 seconds.

[0064] (5) Post-molding treatment: Remove the parts, deburr and trim them; if there are parts that cannot be formed as a whole, the workpiece can be further processed according to the above post-molding treatment steps.

[0065] Before molding, the carbon fiber prepreg can be sandblasted and / or wiped with organic solvents such as isopropyl ketone to increase bonding strength.

[0066] In Example 1, the order of preparation and processing of the main material and auxiliary material can be varied, or they can be performed simultaneously. In Example 1, the main material can be molded into a blank during the main material processing, and then molded together with the auxiliary material to form a workpiece. The process of molding the main material into a blank can be found in Example 2.

[0067] The workpiece prepared in Example 1 has an electrical conductivity of approximately 10. 3 With a shielding strength of S / cm or higher, the shielding effectiveness can reach approximately 65dB or more in the 10kHz-18GHz range, and the workpiece strength is not less than 2.5GPa, achieving good electromagnetic shielding effectiveness and tensile strength. The national standards for the above tests are GB / T15662-1995, GB / 30142-2013, and GB / T1040.1-2006, respectively.

[0068] Example 2:

[0069] (1) The main material is 0.25 mm carbon fiber prepreg; the auxiliary materials include epoxy resin and chopped carbon fiber. Based on the total weight of the auxiliary materials, the auxiliary materials include 150 parts of glycidylamine type epoxy resin, 120 parts of 10 mm chopped carbon fiber, and 20 parts of additives. The additives may include thickeners, release agents, coupling agents, plasticizers, curing agents, flame retardants, etc.

[0070] (2) Prepare and process the main material. Cut the carbon fiber prepreg into a spare shape according to the workpiece unfolding diagram. Align and stack the two layers of carbon fiber prepreg and bond them together. Heat the mold to 145℃-155℃. Place the carbon fiber prepreg in the mold according to the positioning. Close the mold and apply pressure. The pressure is about 8 tons / square meter and the time is about 45-65 seconds.

[0071] (3) Post-molding processing of main material: Remove it, deburr and trim the edges, and use it as blank material for later use.

[0072] (4) Preparation and processing of auxiliary materials:

[0073] The weight of the auxiliary materials is determined based on the dimensions of the workpiece;

[0074] a. First, mix the epoxy resin with the mold release agent, plasticizer, coupling agent, and flame retardant, and stir evenly for about 10 minutes;

[0075] b. Add the thickener and hardener evenly, and reach the desired viscosity (e.g., about 25-30 Pa·s) in about 3 minutes;

[0076] c. Apply the mixture prepared above to the inner sides of the upper and lower polyethylene films respectively;

[0077] d. 10 mm short-cut carbon fibers are uniformly deposited and impregnated onto the mixture coated with the lower polyethylene film;

[0078] e. The upper and lower layers are stacked so that the mixture coated on the inner side of the polyethylene film faces the short carbon fiber, and then rolled into a sheet material;

[0079] f. The sheet material is cured by drying at 50°C for 24 hours. This sheet material is used as an auxiliary material and is then cut according to the workpiece unfolding diagram.

[0080] (5) Heat the mold to 145℃-155℃, stack the sheet material in the mold, and place the carbon fiber prepreg in the mold according to the positioning; close the mold and press, the pressure is about 8 tons / square meter, and the time is about 45-65 seconds.

[0081] (6) Post-molding processing: Remove the parts, deburr and trim them; if there are parts that cannot be formed as a whole, the workpiece can be further processed according to the above post-molding processing steps.

[0082] In the above embodiments, the processing order of the main materials and auxiliary materials can be varied, or they can be processed simultaneously.

[0083] The workpiece prepared in Example 2 has an electrical conductivity of approximately 10. 3 With a thickness of S / cm or higher, the shielding effectiveness can reach approximately 85dB or more in the 10kHz-18GHz range, and the workpiece strength is not less than 2.5GPa, achieving good electromagnetic shielding effectiveness and tensile strength. The national standards used for the above tests are GB / T15662-1995, GB / 30142-2013, and GB / T1040.1-2006, respectively. In Example 2, with a higher content of short-cut carbon fibers, the shielding effectiveness can also be higher, for example, reaching 90dB.

[0084] Example 3:

[0085] (1) The main material is 0.25MM carbon fiber prepreg; based on the weight of the auxiliary materials, the auxiliary materials include 100 parts of vinyl resin, 120 parts of inorganic filler, 6 parts of dioctyl phthalate, 6-8 parts of cyclohexanone peroxide and 20 parts of additives, including coupling agent, release agent, thickener, flame retardant, etc.

[0086] (2) Prepare and process the main material. Cut the carbon fiber prepreg into a spare shape according to the workpiece unfolding diagram. Align and stack the two layers of carbon fiber prepreg together. Heat the mold to 140℃-160℃. Place the carbon fiber prepreg in the mold according to the positioning. Close the mold and apply pressure. The pressure is about 8 tons / square meter and the time is about 40-60 seconds.

[0087] (3) Post-molding processing of main material: Remove it, deburr and trim the edges, and use it as blank material for later use.

[0088] (4) Preparation and processing of auxiliary materials:

[0089] The weight of the auxiliary materials is determined based on the dimensions of the workpiece;

[0090] a. Mix the vinyl resin with the additives and dioctyl phthalate, and stir until homogeneous, about 10 minutes;

[0091] b. Mix the above mixture with the inorganic filler and stir until homogeneous, about 20 minutes;

[0092] c. Add cyclohexanone peroxide and stir until homogeneous to form a mixture. The required viscosity is approximately 30 Pa·s.

[0093] d. Coat the inner sides of the upper and lower polyethylene films with the mixture prepared above, and roll them into sheet material;

[0094] e. The sheet material is cured by drying at 50°C for 24 hours. This sheet material is used as an auxiliary material and is then cut according to the workpiece unfolding diagram.

[0095] (5) Heat the mold to 140℃-160℃, place the main material blank in the mold according to the positioning, and place the sheet material in the secondary molding mold; close the mold and apply pressure, the pressure is about 8 tons / square meter; the time is about 60-80 seconds.

[0096] (6) Post-molding processing: Remove the parts, deburr and trim them; if there are parts that cannot be formed as a whole, the workpiece can be further processed according to the above post-molding processing steps.

[0097] In the above embodiments, the order of preparation and processing of main materials and auxiliary materials can be varied, or they can be performed simultaneously.

[0098] The workpiece prepared in Example 3 has an electrical conductivity of approximately 10. 3 With a shielding strength of S / cm or higher, the shielding effectiveness can reach approximately 65dB or more in the 10kHz-18GHz range, and the workpiece strength is not less than 2.5GPa, achieving good electromagnetic shielding effectiveness and tensile strength. The national standards for the above tests are GB / T15662-1995, GB / 30142-2013, and GB / T1040.1-2006, respectively.

[0099] Example 4:

[0100] (1) The main material is 0.25MM carbon fiber prepreg, and the auxiliary material is ABS+PC 30% material (i.e. ABS accounts for 70% and PC accounts for 30%).

[0101] (2) Prepare and process the main material. Cut the carbon fiber prepreg into a spare shape according to the workpiece unfolding diagram. Align and stack the two layers of carbon fiber prepreg and bond them together. Heat the mold to 145℃-155℃. Place the carbon fiber prepreg in the mold according to the positioning. Close the mold and apply pressure. The pressure is about 8 tons / square meter and the time is about 45-65 seconds.

[0102] (3) Post-molding processing of main material: Remove it, deburr and trim the edges, and use it as blank material for later use.

[0103] (4) Prepare and process auxiliary materials: Determine the weight of auxiliary materials according to the size of the workpiece; heat and dry the ABS+PC 30% material at about 100°C for about 4 hours.

[0104] (5) Injection molding: The mold is heated to about 40℃-60℃; the blank is placed in the injection mold according to the positioning and injection molding is performed; the injection temperature is about 230℃-250℃ and the injection pressure is about 80MPa.

[0105] In the above embodiments, the order of preparation and processing of main materials and auxiliary materials can be varied, or they can be performed simultaneously.

[0106] The workpiece prepared in Example 4 has an electrical conductivity of approximately 10. 3 With a shielding strength of S / cm or higher, the shielding effectiveness can reach approximately 65dB or more in the 10kHz-18GHz range, and the workpiece strength is not less than 2.3GPa, achieving good electromagnetic shielding effectiveness and tensile strength. The national standards for the above tests are GB / T15662-1995, GB / 30142-2013, and GB / T1040.1-2006, respectively.

[0107] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure, which is determined by the appended claims.

Claims

1. A process for preparing carbon fiber composite materials, comprising: Prepare carbon fiber cloth, including determining the number of layers of carbon fiber cloth based on the shielding efficiency of the workpiece, and cutting the carbon fiber cloth according to the unfolded diagram of the workpiece. The preparation of carbon fiber cloth also includes heating the mold to a second predetermined temperature; placing the carbon fiber cloth in the mold according to the positioning; and molding the carbon fiber cloth into a blank for later use as the prepared carbon fiber cloth. Prepare auxiliary materials by calculating their weight based on the workpiece dimensions. These materials include thermosetting resin, chopped carbon fibers, and additives. The chopped carbon fibers comprise 30%-60% of the total weight of the auxiliary materials. The thermosetting resin is either epoxy resin or vinyl ester resin. The preparation process involves: uniformly mixing the epoxy resin or vinyl ester resin with the additives to form a mixture; applying the mixture to the inner side of two layers of polyethylene film; depositing the chopped carbon fibers onto the lower polyethylene film; stacking and rolling the two layers of polyethylene film into a sheet; curing the sheet material; and cutting the sheet material according to the workpiece's unfolded diagram to obtain the prepared auxiliary materials. To form the workpiece, heat the mold to the first preset temperature, and lay the prepared carbon fiber cloth and the prepared auxiliary materials in the mold of the molding machine according to the positioning. The prepared carbon fiber cloth and the prepared auxiliary materials are then formed together. The electrical conductivity of the workpiece obtained after molding is not less than 1.0 × 10³ S / cm.

2. The carbon fiber composite material preparation process according to claim 1, wherein the second predetermined temperature is 140 degrees Celsius to 180 degrees Celsius, the molding time of the preform is 40 seconds to 120 seconds, and the molding pressure of the preform is 6-8 tons / square meter.

3. The carbon fiber composite material preparation process according to claim 1 or 2, wherein the auxiliary material further includes inorganic fillers, wherein the weight of the inorganic fillers is greater than or equal to the weight of the resin.

4. A housing for a medical device comprising a carbon fiber composite material manufactured by any one of the carbon fiber composite material preparation processes of claims 1-3, wherein the workpiece of the carbon fiber composite material has an electrical conductivity of not less than 1.0 x 10³ S / cm and a strength of not less than 2.0 GPa.