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CN-121973467-A - Preparation process of sedimentation bed of warp knitting machine for high-pressure compression molding carbon fiber composite material

CN121973467ACN 121973467 ACN121973467 ACN 121973467ACN-121973467-A

Abstract

The invention relates to a preparation process of a sedimentation bed of a warp knitting machine for high-pressure compression molding carbon fiber composite materials, and relates to the technical field of high-performance composite material processing. The technology realizes the light weight and high performance integration of the sedimentation bed through full-flow precise control, and comprises the steps of selecting a T300/T700/T800-grade carbon fiber prepreg, performing laser cutting, performing 0 degree/45 degree/90 degree multi-axial layering, performing gradient pressure die pressing in a block alloy steel die, heating to 150-200 ℃ for curing for 2 hours, and performing dry ice cleaning, surface polishing and ultrasonic nondestructive testing. The nano silicon dioxide particles toughen the resin matrix, the fracture toughness is increased to be more than or equal to 120 MPa.m 1 / 2 , and the distributed thermocouple eliminates bubbles by real-time temperature control and gradient pressure, so that no layering defect exists in the resin matrix. Meets the requirements of the high-speed warp knitting machine on light-weight, high-precision, high-strength, high-modulus and long-service-life key parts.

Inventors

  • SONG ZHIWEI

Assignees

  • 河北盛仕铭新材料有限公司

Dates

Publication Date
20260505
Application Date
20250808

Claims (8)

  1. 1. The preparation process of the sedimentation bed of the warp knitting machine for the carbon fiber composite material formed by high-pressure compression molding is characterized by comprising the following steps of: S1, preparing raw materials, namely selecting a T700 and T800 carbon fiber prepreg as a base material, wherein a resin matrix is epoxy resin, and the resin content is 30-45wt%; S2, cutting raw materials, namely cutting the prepreg in a net size by a laser cutting machine according to the design size of a sedimentation bed, wherein the edge error is less than or equal to 0.1mm; S3, paving and prefabricating, namely performing 0-45-90-degree multi-axial paving on the cut prepreg according to the stress direction of a slot needle bed, wherein after each layer is paved, using a compaction roller to eliminate bubbles, and the total layer number is 8-30; S4, preparing a die, namely adopting an alloy steel die, preheating the die to 150 ℃ and keeping the temperature uniformity error +/-2 ℃ until the surface roughness Ra of the die is less than or equal to 0.5 mu m; S5, high-pressure molding, namely placing the prefabricated part into a mold, applying gradient pressure (initial 5MPa, peak value 30MPa, and pressure maintaining 15 MPa), heating to 200 ℃ and maintaining for 2 hours, cooling to below 50 ℃ after solidification, and demolding; and S6, post-treatment, namely cleaning and removing demolding residues by dry ice, polishing the surface until the roughness Ra is less than or equal to 1.5 mu m, and carrying out nondestructive testing to verify that the inside has no layering defect.
  2. 2. The process for preparing the sedimentation bed of the warp knitting machine for the high-pressure compression molding carbon fiber composite material, which is disclosed in claim 1, is characterized in that the raw material cutting in the step S2 adopts a laser cutting machine to cut the prepreg in a net size, the cutting power is 300-500W, and the cutting speed is 10-20mm/S.
  3. 3. The process for preparing a sedimentation bed of a warp knitting machine for high-pressure compression molding carbon fiber composite materials according to claim 1, wherein the compacting roller in the step S3 eliminates bubbles at a pressure of 8-12N/cm 2 .
  4. 4. The process for preparing the sedimentation bed of the warp knitting machine for the high-pressure compression molding carbon fiber composite material, which is disclosed in claim 1, is characterized in that the gradient pressure in the step S5 is specifically as follows: initial 5MPa for 5min, peak 30MPa for 10min, and pressure maintaining 15MPa for 5min.
  5. 5. The process for preparing the sedimentation bed of the warp knitting machine for the high-pressure compression molding carbon fiber composite material, which is disclosed in claim 2, is characterized in that the nondestructive detection in the step S6 adopts an ultrasonic flaw detector (frequency is 5MHz, sensitivity phi 2mm flat bottom hole) to detect that the interior of the sedimentation bed is free of layering defects.
  6. 6. The process for preparing the sedimentation bed of the warp knitting machine for the high-pressure compression molding carbon fiber composite material, which is disclosed in claim 1, is characterized in that in the step S5, a plurality of groups of distributed thermocouples are integrated in a mold, the temperature distribution is monitored in real time, the heating power is dynamically regulated, and the temperature fluctuation range is controlled within +/-2 ℃.
  7. 7. The process for preparing the sedimentation bed of the warp knitting machine for the high-pressure compression molding carbon fiber composite material, which is disclosed in claim 1, is characterized in that in the step S5, 1.5-2.0wt% of nano silicon dioxide particles are added in a resin curing stage, the particle size is 20-50nm, and the fracture toughness of a resin matrix is improved to be more than or equal to 120 MPa.m 1 / 2 .
  8. 8. The process for preparing the sedimentation bed of the warp knitting machine for the high-pressure compression molded carbon fiber composite material, as claimed in claim 1, is characterized in that in the step S6, plasma is adopted to etch the surface until micro-roughening (Ra=1.5-1.8 μm), and a graphene coating (the thickness is 50-100 nm) is coated, and the friction coefficient of the coating is less than or equal to 0.15.

Description

Preparation process of sedimentation bed of warp knitting machine for high-pressure compression molding carbon fiber composite material Technical Field The invention relates to the technical field of high-performance composite material processing, in particular to a preparation process of a sedimentation bed of a warp knitting machine for forming a carbon fiber composite material by high-pressure compression molding. Background Warp knitting machines are used as core equipment in the modern textile industry, and a sinking bed (grooved needle bed) is a key functional component for controlling the movement track of grooved needles, so that the knitting precision of fabrics and the running stability of equipment are directly affected. The traditional sedimentation bed is mainly processed by high-strength alloy steel (such as 42 CrMo), has certain rigidity and wear resistance, but has high density (7.8 g/cm 3) and heavy weight, so that the inertia of moving parts of equipment is large, the running speed of a warp knitting machine is limited (generally less than or equal to 800 times/min), fatigue cracks are easy to generate after long-term high-frequency impact load, and the maintenance cost is high. Along with the rapid (target more than or equal to 1500 times/min), light weight and intelligent upgrading of the textile industry, the development of novel sedimentation bed materials with high strength, low weight, high precision and long service life and the preparation process thereof become technical problems to be solved in the industry. Carbon fiber composite materials (CFRP) are regarded as ideal choices for replacing metal materials because of the advantages of low density (1.5-2.0 g/cm 3), high specific strength (more than or equal to 2000 MPa.m/kg), strong designability and the like. However, the existing carbon fiber settling bed preparation process has the following technical bottlenecks: The mechanical property matching is insufficient, the traditional layering process mostly adopts unidirectional or bidirectional layering, is difficult to adapt to complex stress working conditions (with axial stretching, transverse bending and shearing loads) of a sedimentation bed, has low interlayer shearing strength (less than or equal to 60 MPa), poor shock resistance and easy occurrence of layering failure in service, and has insufficient toughness (fracture toughness less than or equal to 80 MPa.m 1/2) of a resin matrix, so that the fatigue resistance requirement under high-frequency impact cannot be met. The molding precision and the surface quality have the defects that the edge error of the prepreg subjected to mechanical cutting is large (more than or equal to 0.5 mm), the temperature uniformity of a die is poor (more than or equal to +/-5 ℃ C.), the dimensional deviation of a sedimentation bed after molding is out of tolerance (more than or equal to +/-0.5 mm), the surface roughness Ra is more than or equal to 3.2 mu m, the precision matching requirement of a grooved needle (less than or equal to 0.05 mm) cannot be met, the traditional release agent is not thoroughly cleaned, the grooved needle is easy to be blocked, and the knitting precision is influenced. The defect control and the process stability are poor, the bubble removal is insufficient (the porosity is more than or equal to 1 percent) in the mould pressing process, the pressure control is rough (single pressure loading) to cause high internal layering defect rate (more than or equal to 5 percent), the real-time monitoring means is lacking, the curing process (such as the curing degree detection lag) is difficult to quantitatively control, and the yield of finished products is only 70-80 percent, so that the large-scale industrialized application is restricted. The functional surface modification is lacking in that the metal-based sedimentation bed relies on hard chromium plating (thickness is 5-10 mu m) on the surface to improve the wear resistance, but the plating binding force is weak (the cross-cut method is more than or equal to 2 levels) and the friction coefficient is high (more than or equal to 0.3), while the existing carbon fiber surface treatment process (such as sand paper polishing) cannot form a long-acting lubrication interface, so that the abrasion rate of a grooved needle is high (more than or equal to 10 mu m/10 ten thousand times), and the service life of equipment is influenced. Aiming at the problems, a preparation process of a sedimentation bed of a warp knitting machine for molding carbon fiber composite materials by high-pressure compression molding is provided. Disclosure of Invention The invention provides a preparation process of a sedimentation bed of a warp knitting machine for molding carbon fiber composite materials by high-pressure compression molding, aiming at solving the problems in the prior art. In order to solve the technical problems, the invention is realized by the following technical scheme that the prepa