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CN-122011690-A - Liquid crystal polymer 3D printing wire rod and preparation method thereof

CN122011690ACN 122011690 ACN122011690 ACN 122011690ACN-122011690-A

Abstract

The invention relates to a liquid crystal polymer 3D printing wire rod and a preparation method thereof, and relates to the technical field of 3D printing wire rods. The wires consist of TLCP base materials and chopped carbon fibers with specific specification of 20K, are prepared through a double-screw blending granulation-single-screw precise wire drawing secondary extrusion molding process, and are matched with the collaborative design of vacuum pretreatment, gradient temperature control and large-inner-diameter wire coil winding, so that the problem of printing of stuck materials and industrial pain points of brittle fracture of carbon fiber modified wires caused by uneven wire diameters of pure TLCP wires is solved. The wire diameter precision of the finished wire rod reaches 1.75mm plus or minus 0.03mm, the tensile strength is more than or equal to 120MPa, the elongation at break is more than or equal to 3.5%, the porosity is less than or equal to 1.2%, the 3D printing extrusion is smooth and free of jamming, the dimensional deviation of the formed product is less than or equal to plus or minus 0.1mm, and the high-precision FDM printing scene is adapted.

Inventors

  • GUAN QINGBAO
  • CAO DEFENG

Assignees

  • 苏州光谨高新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260202

Claims (5)

  1. 1. The liquid crystal polymer 3D printing wire is characterized by comprising, by mass, 80-95 parts of a TLCP base material and 5-20 parts of 20K chopped carbon fibers, wherein the 20K chopped carbon fibers are single-bundle chopped carbon fibers containing 20000 monofilaments, the length is 0.1-0.5 mm, the wire diameter is 1.6-3.0 mm, the wire diameter tolerance is less than or equal to +/-0.08 mm, the tensile strength is more than or equal to 95MPa, the elongation at break is more than or equal to 2.5%, the porosity is less than or equal to 1.4%, and the liquid crystal polymer 3D printing wire is suitable for Fused Deposition Modeling (FDM) 3D printing equipment, no clamping material exists in the printing process, the extrusion is smooth, and the size deviation of a formed product is less than or equal to +/-0.1 mm.
  2. 2. The 3D printing adaptive carbon fiber blending modified TLCP wire according to claim 1, wherein the interface bonding strength of the 20K chopped carbon fiber and the TLCP base material is more than or equal to 30MPa, the dispersion uniformity of the carbon fiber is more than or equal to 92%, the UL 94V-0 level flame retardant effect can be achieved, compared with a pure TLCP wire (the line diameter tolerance is generally more than or equal to +/-0.1 mm) without adding the carbon fiber, the uniformity of the line diameter of the modified wire is improved by more than 70%, the problem of 3D printing clamping caused by the uneven line diameter of the pure TLCP wire is thoroughly solved, the 3D printing device can be completely adapted to Fused Deposition Modeling (FDM) type 3D printing equipment, the extrusion amount in the printing process is stable, the size deviation of a molded product is less than or equal to +/-0.1 mm, and the high temperature stability is improved by more than 30%.
  3. 3. A method for preparing the 3D printing adapted carbon fiber blending modified TLCP wire as claimed in any one of claims 1 to 2, comprising the steps of: (1) The method comprises the steps of raw material pretreatment, namely placing a TLCP base material and 20K chopped carbon fibers in a vacuum drying oven, wherein the temperature control precision of the vacuum drying oven is less than or equal to +/-2 ℃, the vacuum degree control precision is less than or equal to +/-0.005 MPa, and drying for 4-6 hours under the conditions of 120-140 ℃ and minus 0.10-0.08 MPa to remove moisture and volatile impurities; (2) Blending, extruding and granulating, namely weighing the pretreated raw materials according to a proportion, putting the raw materials into a double-screw extruder, wherein the length-diameter ratio of the screw of the double-screw extruder is 40-50:1, the diameter of a die orifice is 2-6 mm, the temperature of each area of a machine barrel is set to be 290-310 ℃, the rotating speed of the screw is 8-12 r/min, the rotating speed of a charging pump is 180-210 r/min, uniformly blending and melting the raw materials is realized through the strong shearing action of the double screws, and granulating after the extruded strip materials are cooled to room temperature, so as to obtain modified TLCP particles; (3) And (3) wiredrawing and molding, namely putting the modified TLCP particles into a single screw extruder, wherein the length-diameter ratio of the screw of the single screw extruder is 30-40:1, the diameter of a die orifice is 1.0-3 mm, the temperature of each region of a charging barrel is set to be 310-325 ℃, the temperature of a chuck region and the temperature of a die head region are set to be 310-320 ℃, the rotating speed of a host machine is 20-30 r/min, the traction speed is 5-9 m/min, the speed of a conveyor belt is 4-8 m/min, the winding speed is 35-45 m/min, extruding filaments through a precise wiredrawing die (the aperture precision is less than or equal to +/-0.01 mm), cooling to room temperature, and finally winding through a wire coil with the inner diameter of more than or equal to 200mm to obtain the target wire. Compared with the traditional PA/PLA wire preparation process, the wire diameter precision is improved by more than 40%, the wire porosity is reduced by more than 30%, the brittle fracture rate in the winding and printing processes is obviously reduced, the 3D printing technology is adapted, the fluctuation range of the mechanical property of the formed product is reduced to +/-5%, the service life is prolonged by more than 2 times, the excellent wire diameter uniformity can be adapted to FDM printer nozzles of different types, the phenomena of material clamping and wire breakage are avoided when complex structural members are printed, and the forming efficiency is improved by more than 30%.
  4. 4. The method of claim 3, wherein the gradient temperature control system of step (2) is cooperated with the strong shearing action of the twin screw, the temperature matching system of step (3) is precisely proportioned with the traction-winding speed, the uniform dispersion of the carbon fibers in the TLCP base material is jointly ensured, the stress concentration caused by fiber aggregation is avoided, and the consistency of the section of the wire is precisely controlled.
  5. 5. An application of the 3D printing adaptive carbon fiber blending modified TLCP wire as claimed in any one of claims 1-2 in 3D printing of high-precision structural members.

Description

Liquid crystal polymer 3D printing wire rod and preparation method thereof Technical Field The invention belongs to the technical field of 3D printing wires, and relates to a carbon fiber blending modified TLCP wire with improved wire diameter uniformity and a preparation method thereof. Background 3D printing technology (especially fused deposition modeling, namely FDM technology) is increasingly widely applied in the field of rapid preparation of structural parts due to flexible modeling and controllable equipment cost. The Thermotropic Liquid Crystal Polyester (TLCP) is used as a high-performance engineering plastic, has excellent heat resistance, mechanical strength and dimensional stability, and is one of potential base materials of the 3D printing high-performance wire rod. However, the pure TLCP wire has obvious technical bottlenecks in the practical FDM printing, namely, on one hand, the TLCP melt viscosity is sensitive to temperature and shear rate, the traditional single-step extrusion molding process is difficult to accurately control the section consistency of the wire, the fluctuation of the wire diameter (common tolerance exceeding +/-0.1 mm) is easy to occur, the frequent clamping of a spray head and the unstable extrusion amount in the printing process are caused, and finally the precision and the molding quality of a product are influenced, and on the other hand, the pure TLCP wire is insufficient in rigidity and toughness matching property, the problem that the interlayer bonding force of the printed product is poor and the shock resistance is weak is easy to occur, and the application of the pure TLCP wire in a high-requirement structural member is limited. In order to improve the mechanical property of the TLCP wire, carbon fiber is introduced as a reinforcing phase, and the carbon fiber has the characteristics of high specific strength and high modulus, so that the tensile strength and rigidity of the wire can be effectively improved. However, the conventional carbon fiber modified TLCP wire still has the key defects that firstly, the interface bonding property of the carbon fiber and the TLCP base material is insufficient, the problem of uneven dispersion and agglomeration of the carbon fiber easily occurs due to direct blending, so that stress concentration points exist in the wire, secondly, the carbon fiber proportion is difficult to balance, for example, although the mechanical strength of the carbon fiber modified TLCP wire with 20% mass fraction is obviously improved, the brittleness of the wire is obviously increased, breakage easily occurs in the winding and printing processes, meanwhile, the core problem of uneven wire diameter still cannot be solved under the traditional extrusion process, thirdly, the conventional preparation process adopts single extrusion molding, the uniform dispersion of the carbon fiber and the molding stability of the wire cannot be considered, and the modified wire is either out of tolerance or has large fluctuation of mechanical property, so that the adaptation requirements of FDM printing are difficult to be met. Therefore, developing a carbon fiber blending modified TLCP wire and an adaptive preparation method which have both wire diameter uniformity and mechanical properties has important significance for promoting the application of TLCP in 3D printing high-performance structural members. Disclosure of Invention Aiming at the problems that pure TLCP wires are uneven in wire diameter, carbon fiber modified TLCP wires are easy to crack and poor in adaptability in the prior art, the invention provides a 3D printing-adaptive carbon fiber blending modified TLCP wire and a preparation method thereof, and double improvement of wire performance and printing adaptability is realized through 'accurate matching of raw material specifications and cooperative optimization of multiple links of a process'. The invention provides a 3D printing adaptive carbon fiber blending modified TLCP wire which consists of 80-97.5% of TLCP base material and 2.5-20% of 20K chopped carbon fibers by mass, wherein the parameters of the chopped carbon fibers are tow specifications of 20K (single tow contains 20000 monofilaments) and the length of the chopped carbon fibers is 0.1-0.5 mm, the wire diameter of the wire is 1.75mm plus or minus 0.03mm, and the wire is adaptable to FDM 3D printing equipment, and meets the requirements of no jamming and smooth extrusion in the printing process. The invention provides a preparation method of the wire rod, which is characterized in that the core is that the problems of uneven wire diameter and brittle failure are solved by matching raw material specifications and precisely matching technological parameters, and the preparation method specifically comprises the following steps: 1. the raw material pretreatment, namely vacuum drying TLCP and carbon fibers with specific specifications, synchronously removing moisture and impurities, avoiding