CN120115701A

CN120115701A - Electric hair clipper moving blade blank and its production process, injection molding mold

Info

Publication number: CN120115701A
Application number: CN202510360453.3A
Authority: CN
Inventors: 屠友事; 邢友甜; 朱雨航
Original assignee: Ningbo Gelin Taike Metal Materials Co ltd
Current assignee: Ningbo Gelin Taike Metal Materials Co ltd
Priority date: 2025-03-26
Filing date: 2025-03-26
Publication date: 2025-06-10

Abstract

A method for producing the blade blank of electric hair clipper includes such steps as preparing a set of injection mould, S1, preparing composite raw materials, S3, preparing the blade blank of electric hair clipper, S4, sealing in mould to obtain sealing layer, S5, degreasing in degreasing furnace, S6, high-temp sintering in sintering furnace to obtain shrinkage rate of 16.5+/-0.5%, S7, heat treating to harden, and S8, forming sliding blade edge. The production process provided by the invention can solve the problem that the ceramic is easy to collapse, the problem that the stainless steel temperature of the traditional machining stainless steel blade is raised and the tooth is difficult to open, and the problem that the acute angle stamping die of the stamping blade is difficult to manufacture. The process is simple, the production efficiency is extremely high, the method is suitable for mass production, and the development cost and the production cost can be greatly reduced.

Description

Electric clipper movable blade blank, production process thereof and injection molding die

Technical Field

The invention relates to a blade blank of an electric hair clipper movable blade, a production process thereof and an injection molding die.

Background

Hair clippers are known as a common hair clipper, and are used mainly for cutting human hair or animal body hair. The hair clipper comprises a shell and a motor arranged in the shell, wherein a fixed blade is fixedly arranged at the front end of the shell, a movable blade is fixedly arranged at the front end of a swinging head through a swinging frame, and the motor drives the swinging head to swing left and right, so that the movable blade is driven to move left and right relative to the fixed blade, and the hair clipping function is realized. The motor is classified into a rotating motor, which is a rotating electromagnetic machine operated by means of an electromagnetic induction principle, for achieving mutual conversion of mechanical energy and electric energy, and a swinging motor, which converts a rotating motion into a reciprocating swing by means of a transmission mechanism, such as a cam mechanism, an eccentric link mechanism, in general.

The shaver blade is a main working part in the shaver or the shaver, and the existing shaver or the shaver mainly comprises a rotary type shaver and a reciprocating type shaver, and the shaver blade is relatively moved relative to the fixed blade net by rotating or swinging the shaver blade on the head of the shaver or the shaver so as to cut off hairs entering the space between the shaver blade and the fixed blade net. The cutting end of the razor blade is typically provided with a plurality of cutting teeth at intervals, the edge sharpness of which and the shape of which greatly affect the cutting effect of the hair.

The movable blade in the market is mainly made of ceramics at present, the ceramic processing difficulty is high, and the defects of tooth breakage and the like are easily caused by extremely poor toughness. The stainless steel material is punched and then grooved by special grooving equipment, but the grooving equipment is special and has high price, burrs are difficult to remove after grooving, sharpness of the stainless steel material cannot be poor due to the fact that sharp angles cannot be formed, meanwhile, the temperature rise of the stainless steel material moving blade is high, the stainless steel material is easy to burn, and experience of consumers is poor.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a production process of a blade blank of an electric hair clipper

The invention solves the technical problems that the production process of the knife blank of the moving knife blade comprises the following steps:

s1, manufacturing a set of injection molding die;

s2, preparing composite raw materials, mixing and banburying at 170+/-5 ℃ and granulating and drying to obtain particles of the composite raw materials with the particle size of 5+/-2 mm;

S3, placing the injection molding die into a precise injection molding machine, then adding particles of the composite raw materials into the precise injection molding machine, and manufacturing a moving blade blank through an injection molding process, wherein the moving blade blank comprises an upper fixed section and a lower sliding section, the lower sliding section is provided with a tooth-shaped part, the tooth-shaped part comprises a plurality of unit teeth, and tooth-space grooves are formed between every two adjacent unit teeth;

S4, performing in-mold sealing treatment on the lower sliding section of the knife blank of the movable knife blade to form a sealing layer;

S5, placing the knife blank of the movable knife blade in the ceramic plate, and then integrally placing the ceramic plate into a degreasing furnace for degreasing;

s6, placing the degreased movable blade blank into a sintering furnace for high-temperature sintering, wherein the shrinkage rate during sintering is 16.5+/-0.5%;

S7, placing the sintered movable blade blank into a heat treatment furnace for heat treatment hardening;

S8, forming a sliding movable cutter cutting edge on the tooth-shaped part through a grinding and grinding process to obtain a finished product of a movable cutter blade blank;

in the step S2, the composite raw material is a combination of metal powder and an adhesive, and the weight ratio of the metal fusion powder to the adhesive is 10.6:1;

The metal fusion powder comprises, by weight, 85% -95% of 440C stainless steel or M2 steel metal powder, and 15% -5% of aluminum oxide powder or zirconium oxide powder;

Wherein the binder comprises, by weight, 81.2% + -1% of polyoxymethylene, 7.1% + -1% of high-density polyethylene, 4.6% + -1% of styrene-acrylonitrile copolymer and 7.1% + -1% of antioxidant 1010.

Optionally, in step S3, the thickness dimension of the obtained moving blade blank is less than or equal to 3mm±1%o.

Optionally, in step S4, the thickness T of the sealing glue on the lower sliding section of the moving blade blank is greater than 0.25mm, and the depth H of the inter-tooth groove after sealing glue is greater than or equal to 0.15mm.

Optionally, in the step S5, degreasing temperature is 90-120 ℃, degreasing medium oxalic acid is used, and degreasing time is 6-10 h.

Optionally, in step S6, the sintering temperature in the first stage is raised from room temperature to 600 ℃, and the sintering time in the first stage lasts for 5-6 hours;

The sintering temperature of the second stage is increased from 600 ℃ to 1050 ℃, and the sintering time of the second stage lasts for 6-8 hours;

The sintering temperature of the third stage is increased from 1050 ℃ to 1300 ℃, and the sintering time of the third stage lasts for 8-10 h;

The sintering temperature of the fourth stage is reduced from 1300 ℃ to 1100 ℃, and the sintering time of the fourth stage lasts for 5-6 h;

the sintering temperature in the fifth stage is reduced from 1100 ℃ to room temperature, and the sintering time in the fifth stage lasts for 3-5 h.

Optionally, in step S7, the heat treatment temperature is set at 1045-1055 ℃, the hardness of the moving blade blank obtained after the heat treatment is HRC 61-65, and then the moving blade blank is tempered, and the hardness of the moving blade blank obtained after the tempering treatment is HRC 57-60.

Optionally, in step S8, the angle of the movable cutter cutting edge formed by the grinding and polishing process is 45-55 degrees, and the movable cutter cutting edge opening is provided with an arc chamfer R, and the radius of the arc chamfer R is 0.10-0.20mm.

The other important scheme of the invention is that the electric hair clipper movable blade blank is manufactured by adopting the production process of the electric hair clipper movable blade blank, the movable blade blank is provided with the upper fixing section and the lower sliding section, the upper fixing section is also provided with a positioning groove and an assembly hole, the upper end face of the lower sliding section is provided with the unit tooth, and the lower end face of the lower sliding section is provided with an acute angle groove matched with the unit tooth.

The other important scheme of the invention is that the injection molding die is used for molding a knife blank of a movable knife blade and comprises a male die and a female die, wherein the male die is provided with a parting core and a main glue feeding groove, and the female die is provided with a cavity matched with the parting core;

the male die is provided with a first bulge, a square column insert for forming the positioning groove and a cylindrical insert for forming the assembly hole;

The female die is provided with a second bulge.

Preferably, the injection molding die is also provided with a sealing runner, and the sealing runner comprises a glue inlet section, a detour section, a glue outlet trunk section and a plurality of glue outlet branch sections which are communicated in sequence from front to back;

the glue feeding section is positioned in the middle of the lower side area of the male die and is provided with a secondary glue feeding groove;

The detour section is positioned on the female die, and the detour section has 2 sections and is symmetrically distributed on two sides of the die cavity;

the glue outlet trunk section is positioned in the upper side area of the male die;

the glue outlet branch sections are positioned on the male die, and the glue outlet branch sections correspond to unit teeth of the moving blade blank one by one.

The invention has the beneficial effects that:

1. The process is simple, the production efficiency is extremely high, the method is suitable for mass production, and the development cost and the production cost can be greatly reduced.

2. The production process provided by the invention can solve the problem that the ceramic is easy to collapse, the problem that the stainless steel temperature of the traditional machining stainless steel blade is raised and the tooth is difficult to open, and the problem that the acute angle stamping die of the stamping blade is difficult to manufacture.

3. The mold forming can be realized by replacing the mold insert, so that the design is convenient.

Drawings

FIG. 1 is a flow chart of the production process in the present invention.

Fig. 2 is a schematic view of the structure of a knife blank of the movable knife blade in the invention.

Fig. 3 is an enlarged schematic view of the portion a in fig. 2.

Fig. 4 is a schematic diagram of the seal layer on the front and back sides of the knife blank of the movable knife blade.

Fig. 5 is a front view of a movable blade blank and a partial enlarged view of the same.

Fig. 6 is a schematic view of the injection mold of the present invention when closed.

Fig. 7 is an exploded view of the structure of the injection mold of the present invention.

Fig. 8 is a schematic view showing a partial structure of a male mold on an injection molding mold according to the present invention.

FIG. 9 is a schematic view showing a part of a master mold of an injection mold according to the present invention.

Fig. 10 is a schematic view of a molding runner on an injection mold.

In the figure, 1, a movable blade blank, 11, an upper fixing section, 111, a positioning groove, 112, an assembly hole, 12, a lower sliding section, 13, a tooth-shaped part, 131, a unit tooth, 132, an interdental groove, 133, a sharp angle groove, 14, a sealing adhesive layer, 2, a male die, 21, a parting core, 22, a main adhesive feeding groove, 23, a first bulge, 24, a square column insert, 25, a cylindrical insert, 3, a female die, 31, a cavity, 32, a second bulge, 4, an adhesive sealing runner, 41, an adhesive feeding section, 411, a secondary adhesive feeding groove, 42, a bypass section, 43, an adhesive outlet trunk section, 44, an adhesive outlet branch section, H, the depth of the groove and R arc tooth space chamfer are shown.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

Referring to fig. 1 to 10, a process for producing a moving blade blank 1 includes:

S1, manufacturing a set of injection molding die. The specific tooth shape and pattern required by the movable blade blank can be customized according to the requirements of customers, the mold is convenient to replace the insert, and the pattern can be diamond, triangle and the like and can be molded by the mold. The die is simple to process, the sharp angle of the difficult sharp edge of machining can be easily obtained through electrode discharge machining. The minimum tooth-shaped structure can be 0.20mm.

S2, preparing composite raw materials, mixing and banburying at 170+/-5 ℃ and granulating and drying to obtain particles of the composite raw materials with the diameter of 5+/-2 mm, wherein the particles can be quickly and uniformly melted in the injection molding process, the risks of unmelted particles or local overheating are reduced, the dust problem caused by agglomeration or undersize of the particles is avoided, the feeding is smooth, the blocking or bridging phenomenon is reduced, the stability of continuous production is improved, the tolerance range of +/-2 mm has lower requirements on the granulating process, the large-scale production is suitable, and the raw material processing cost is reduced.

S3, placing an injection molding die into a precise injection molding machine (an external picking part, such as a sea-sky brand injection molding machine and the like), then adding particles of composite raw materials into the precise injection molding machine, manufacturing a movable cutter blade blank 1 through an injection molding process, and forming a movable cutter blade with a required shape through selection of the injection molding die, wherein the movable cutter blade blank 1 comprises an upper fixed section 11 and a lower sliding section 12, a tooth-shaped part 13 is arranged at the lower sliding section 12, the tooth-shaped part 13 comprises a plurality of unit teeth 131, and tooth-space grooves 132 are formed between the adjacent unit teeth 131.

S4, carrying out in-mold sealing treatment on the lower sliding section 12 of the knife blank 1 of the movable knife blade to form a sealing layer 14, wherein the sealing material can be engineering plastics, TPE (thermoplastic elastomer) and the like, after the sealing layer is coated, the stress born by the tooth-shaped part 13 during cutting is dispersed, the risk of tooth breakage or fracture is reduced, the colloid absorbs vibration and impact energy, the service life of the knife blade in high-frequency use is prolonged, on the other hand, the colloid completely wraps the joint of the front tooth and the knife blank, moisture and chemical substances are prevented from penetrating, metal oxidation or corrosion is avoided, and meanwhile, the sealing layer can cover sharp edges, and the risk of accidental cutting injury is reduced.

S5, placing the movable cutter blade blank 1 in a ceramic plate, then integrally placing the ceramic plate in a degreasing furnace for degreasing, wherein in the degreasing process, the ceramic plate (such as alumina and silicon carbide) can resist the high-temperature environment (usually 200-600 ℃) required by degreasing, deformation or release of harmful gas of a supporting plate is avoided, the ceramic plate has extremely small dimensional change at high temperature, the flat ceramic plate surface enables a workpiece to be heated uniformly, cracking or warping caused by thermal stress is reduced, stable product placement in the degreasing process is ensured, workpiece displacement or deformation caused by deformation of a support is reduced, on the other hand, ceramics do not react with degreasing solvents (such as water-based, solvent-based or catalytic degreasing agents) or decomposition products (such as acid and hydrocarbon) to avoid polluting the workpiece, and meanwhile, the thermal conductivity of the ceramics is between metal and refractory bricks, so that uneven degreasing caused by local overheating can be avoided, heat can be prevented from being rapidly dissipated, and the degreasing efficiency is improved.

S6, placing the degreased movable cutter blade blank 1 into a sintering furnace for high-temperature sintering, wherein the shrinkage rate during sintering is 16.5+/-0.5%, and the strict limit on the shrinkage rate during sintering is used for ensuring the expected dimensional accuracy of a product in the high-temperature densification process, optimizing the material performance and structural uniformity, improving the process stability and yield, supporting complex structural design and adapting to special-shaped parts. The width dimension of the movable blade blank 1 before high temperature sintering is 11.65mm, and the width dimension of the movable blade blank 1 after high temperature sintering in step S6 is 10mm, for example.

S7, placing the sintered moving blade blank 1 into a heat treatment furnace for heat treatment hardening, so that the microstructure and phase composition of the material are regulated and controlled through heat treatment, and the mechanical property, the dimensional stability and the service life of the material are further improved.

S8, forming a sliding movable cutter cutting edge on the tooth-shaped part 13 through a grinding and grinding process to obtain a finished product of the movable cutter blade blank 1, wherein the good movable cutter cutting edge can cut off hair rapidly with minimum resistance, reduce the pull feeling and avoid pain and skin irritation.

In the step S2, the composite raw material is a combination of metal powder and an adhesive, and the weight ratio of the metal fusion powder to the adhesive is 10.6:1; the composite raw materials in the proportion have the advantages that firstly, the green strength and the structural stability are optimized, 8.6% of the binder is enough to form physical bridging among powder particles, the basic mechanical strength of the green body (before sintering) is endowed, the collapse of complex structures (such as thin walls and fine features) in the process of carrying or degreasing is prevented, meanwhile, excessive softening is avoided, namely, compared with the proportion of the binder which is higher than 30%, the deformation risk of the green body caused by the softening of the binder can be reduced by the binder with low content of the binder; the method has the advantages of reducing degreasing difficulty and residue risks, shortening degreasing time (such as thermal degreasing or solvent degreasing) due to low binder content, reducing energy consumption, reducing air holes or crack risks caused by binder residues, reducing pollutants generated after low-proportion binder decomposition, meeting environmental protection requirements, improving sintering efficiency and material compactness, reducing porosity, ensuring that pores left after binder burning are smaller and uniformly distributed, enabling metal powder to fill the pores through solid-phase or liquid-phase sintering during sintering, improving material compactness, inhibiting grain coarsening, namely inhibiting overgrowth of metal grains by a small amount of binder decomposition products, refining microstructures, enhancing material strength, balancing cost and performance, reducing binder consumption, directly reducing raw material cost, shortening degreasing and sintering time, improving production efficiency, and ensuring that low binder residues have small influence on electric conductivity, thermal conductivity or corrosion resistance of metal materials.

The metal fusion powder comprises, by weight, 85% -95% of 440-C stainless steel or M2 steel metal powder (with a powder grade D50 of 8-10 mu M), 15% -5% of aluminum oxide powder or zirconium oxide powder, a product processed by the metal fusion powder with the proportion has a ceramic strengthening effect, namely, the addition of 15% -5% of aluminum oxide powder or zirconium oxide powder can remarkably improve the surface hardness of a composite material, reduce the abrasion rate, and enable the chemical properties of aluminum oxide/zirconium oxide to be stable, a compact barrier can be formed on the metal surface, oxidation or chemical corrosion can be delayed, a metal matrix provides toughness, ceramic particles are embedded into the metal matrix as a hard phase to form a metal-ceramic composite structure, the metal fusion powder is suitable for a high-speed friction or strong abrasion scene, the stainless steel is a stainless steel substrate, 440C stainless steel contains 16% -18% of chromium and has good corrosion resistance, the M2 steel is slightly weak in corrosion resistance, corrosive media can be isolated through a ceramic coating, the complementation of metal and ceramic is achieved, the 440C stainless steel has a heat-resistant temperature of about 800 ℃, and the aluminum oxide/zirconium oxide temperature can reach 600 ℃ and the temperature of 205 ℃ respectively. The composite material can bear higher temperature (such as more than 1000 ℃) and is suitable for wear-resistant parts in high-temperature environments, light weight is realized, namely, the densities of aluminum oxide (3.9 g/cm ³) and zirconium oxide (6.0 g/cm ³) are lower than those of steel (7.8 g/cm ³), the density of the whole material can be reduced after the composite material is added, the sintering process is facilitated, and ceramic particles can inhibit overgrowth of metal grains, refine microstructures and improve the strength of the material.

Wherein the binder comprises, by weight, 81.2% + -1% of polyoxymethylene, 7.1% + -1% of high-density polyethylene, 4.6% + -1% of styrene-acrylonitrile copolymer and 7.1% + -1% of antioxidant 1010. The adhesive with the proportion realizes optimization among strength, toughness, processability and degreasing compatibility through the synergistic modification of POM and HDPE/SAN, and is particularly suitable for the field of metal powder molding with high requirements on comprehensive performance.

Optionally, in step S3, the thickness dimension of the obtained moving blade blank 1 is 3mm±1%o or less. The thickness dimension of the movable cutter blade blank 1 at this stage is slightly larger than the actual dimension, so that the proper dimension is provided for the finish machining of the subsequent step.

Optionally, in step S4, the thickness T of the sealing glue on the lower sliding section 12 of the movable blade blank 1 is more than 0.25mm, on the other hand, the depth H of the interdental groove 132 after sealing glue is more than or equal to 0.15mm. The thickness of the sealing adhesive layer 14 is enough to play a plurality of roles, such as oxidation prevention and corrosion prevention, the sealing adhesive layer 14 can isolate air, moisture or corrosive media, the surface of a cutter blank (such as a metal cutting edge) is protected from oxidation or chemical erosion, the service life of a cutter is prolonged, the thicker sealing adhesive layer 14 can absorb slight impact or vibration, the edge of the cutter blank is reduced from tipping or abrasion caused by external force, the deformation resistance is improved, the sealing adhesive layer 14 can provide additional support for ultrathin or easily deformed cutter blanks (such as ceramic blades) to prevent bending deformation caused by thermal expansion and contraction or external force, the uniform stress distribution is realized, the sealing adhesive layer 14 can relieve the residual stress in the cutter blanks after sintering or heat treatment, the cracking risk is reduced, and the sealing adhesive on the outermost layer can serve as a sacrificial layer in the subsequent grinding or polishing process, so that the non-working area of the cutter blank is prevented from being damaged in the processing process.

Optionally, in step S5, degreasing medium oxalic acid is taken as an acidic degreasing agent, the oxalic acid can be subjected to saponification or hydrolysis reaction with an organic binder on the surface of the tool blank to destroy the structure of the organic matters so as to be dissolved or dispersed in the solution, and the oxalic acid slightly etches the surface of the metal or ceramic to remove an oxide layer or pollutants so as to provide a clean interface for subsequent sintering. Degreasing temperature is 90-120 ℃, oxalic acid decomposition temperature is about 150 ℃, but the degreasing agent can play a role stably at 90-120 ℃, so that molecular kinetic energy is improved, and organic matter decomposition time is shortened. The degreasing time is 6-10 h, so that the requirement of full degreasing is met, the thick cutter blank or the complex structure needs enough time to allow oxalic acid to permeate and dissolve deep organic matters, the efficiency and the cost are balanced, the degreasing is incomplete due to too short time to influence the subsequent sintering (such as gas holes caused by residual carbide), the energy consumption and the equipment occupation are increased due to too long time, the stability of materials is met, and the surface of the cutter blank is possibly excessively rough or the crystal phase is possibly changed due to the long-time action of oxalic acid.

As one of the core process points of the present invention, the temperature and time control of the sintering process in step S6 is specifically as follows:

The first stage sintering temperature is increased to 600 ℃ from room temperature, the first stage sintering time lasts for 5-6 h, and the first stage has the main effects that residual organic matters are decomposed, a small amount of binder decomposition products (CO ₂、H₂ O and the like) remained after the degreasing process are further removed, and pores or cracks caused by gas expansion during high-temperature sintering are avoided. And secondly, evaporating water, removing the water adsorbed by the cutter blank, and preventing the blank structure from being damaged by vapor pressure at high temperature. Thirdly, the temperature of the low temperature section of slow stress release is slowly increased (about 100-120 ℃ per hour), so that the internal stress caused by uneven thermal expansion can be reduced, and the cracking of a blank body is avoided.

The sintering temperature of the second stage is increased from 600 ℃ to 1050 ℃ and the sintering time of the second stage lasts for 6-8 hours, and the main effect of the second stage is that firstly, preliminary sintering is carried out, neck connection is formed among particles through diffusion, the density is gradually increased (about 50% -70% of theoretical density), and a blank body starts to have mechanical strength. And secondly, the gas removal is enhanced, the discharge of residual gases (such as CO and NH ₃) is accelerated at a higher temperature, and meanwhile, the decomposition of the metal complex remained after the degreasing of oxalic acid is promoted. And thirdly, activating grain boundary to provide an active interface for subsequent high-temperature sintering, such as starting rearrangement of crystal grains or softening of glass phase in the ceramic material.

The sintering temperature in the third stage is increased from 1050 ℃ to 1300 ℃ and the sintering time in the third stage lasts for 8-10 h, and the main effect of the third stage is that the temperature is close to the melting point of the material (such as steel-based material about 1400 ℃ and ceramic about 1600 ℃) in the first stage, and the high density (> 95% of theoretical density) is realized through a particle rearrangement and dissolution-precipitation mechanism. And secondly, the pores are closed, the pores are filled with liquid phase or eliminated by diffusion at high temperature, a compact structure is formed, and the hardness and the wear resistance of the cutter are improved. Thirdly, microstructure optimization, controlling grain size (e.g., fine grain strengthening), for example, by adding inhibitors (e.g., carbide particles) to inhibit overgrowth of grains.

The sintering temperature in the fourth stage is reduced from 1300 ℃ to 1100 ℃ and the sintering time in the fourth stage lasts for 5-6 h, and the main effect of the fourth stage is that firstly, phase transformation regulation and control are carried out, certain materials (such as tool steel) are subjected to austenite decomposition near 1100 ℃, the martensite transformation rate is controlled through heat preservation, and the quenching stress is reduced. And secondly, the residual stress is released, the temperature is slowly reduced to be below the phase transition point, and microcracks generated due to heat shrinkage difference are avoided. And thirdly, pre-cooling protection is adopted, the requirement on the subsequent cooling rate is reduced, and the surface cracking caused by direct rapid cooling is prevented.

The sintering temperature in the fifth stage is reduced from 1100 ℃ to room temperature, and the sintering time in the fifth stage lasts for 3-5 h. The fifth stage has the main effects of slow cooling, controlled cooling rate (about 200-300 ℃ per hour), reduced thermal stress concentration, and is especially suitable for ceramic or composite material cutters. Secondly, the final structure is stabilized, so that the metal material is ensured to complete solid phase transformation (such as pearlite formation) or the glass phase of the ceramic material is fully solidified. And thirdly, maintaining the dimensional precision, avoiding the buckling deformation caused by rapid cooling, and meeting the precision requirement of +/-1%o of the thickness of the cutter blank in the step three.

The key logic in the sintering process is that 1, the temperature is controlled in stages, namely the densification and the structural stability are considered in the rising-protecting-falling rhythm, and the coarsening of grains or the accumulation of stress caused by a single high-temperature section is avoided. 2. Time matching, namely the longest time of the high temperature section (the third stage) and ensuring full diffusion, and the heavy safety transition of the low temperature section (the first stage, the fourth stage and the fifth stage). 3. The material is adapted to the fact that the cutter blank contains ceramics, the grain boundary oxidation is avoided near 1300 ℃, and meanwhile, the cutter blank also belongs to a stainless steel metal base, and carbide distribution and hardness are balanced.

In the actual operation process, the abnormal condition needs to be prejudged, and 2 points are mainly needed, firstly, the stage time is insufficient, namely, the first stage is too short, the porosity after sintering is high due to residual gas, and the third stage is too short, the density is insufficient, and the cutter is easy to collapse. And secondly, the cooling rate is too high, namely quenching is carried out in the fifth stage, through cracks appear on the ceramic cutter, and a quenched martensite brittle layer is generated on the metal cutter.

Optionally, in step S7, the heat treatment temperature is set at 1045-1055 ℃, the hardness of the moving blade blank 1 obtained after the heat treatment is HRC 61-65, and then the moving blade blank 1 is tempered to achieve the purposes of stress release, toughness improvement and dimensional stabilization improvement. The hardness of the cutter blank 1 of the movable cutter blade obtained after tempering treatment is HRC 57-60, and the tempering temperature is set to be 200-300 ℃ according to requirements. The hardness after treatment is kept at HRC 57-60, so that the brittleness risk brought by the hardness above HRC60 is avoided while the sharpness of the cutting edge is ensured. In sum, through the quenching-tempering process, the knife blank 1 of the movable knife blade can realize the mechanical properties of hard but not brittle, tough but not soft, and meet the comprehensive requirements of the cutting tool on strength, wear resistance and impact resistance

Optionally, in step S8, the angle of the cutting edge of the movable blade formed by the grinding and polishing process is 45 ° to 55 °. The angle of the cutting edge of a conventional cutting tool (such as a turning tool) is 20-30 degrees, 45-55 degrees belong to a large-angle design, the cutting tool is suitable for the processing requirement of ceramic-stainless steel composite materials, if the angle is less than 45 degrees, the cutting edge is too thin and easy to crack under impact load, and if the angle is more than 55 degrees, the cutting resistance is obviously increased, and the sharpness of the cutting edge is reduced. Therefore, the cutting force can be dispersed at a large angle by increasing the strength of the cutting edge to resist the tipping, so that the plastic deformation of the cutting edge is avoided.

On the other hand, sharp edges (R <0.05 mm) are prone to stress concentration during cutting (local stress can be 3 times the tensile strength of the material), leading to microcrack initiation. Therefore, the movable blade edge opening is provided with the circular arc chamfer RR, and the radius of the circular arc chamfer RR is 0.10-0.20mm. From the test data, the cutting edge of r=0.15 mm is 40% improved over the fatigue life of r=0.05 mm. The cutting performance after machining is more optimized, the arc chamfer R can promote chip curling and reduce chip accumulation and formation, meanwhile, the surface quality is improved, the R value of 0.10-0.20mm can avoid the plow cutting action of the cutting edge on the surface of a workpiece, and the machined surface roughness Ra is reduced by 0.5-1.0 mu m. From the standpoint of process feasibility, if R <0.10mm, a grinding wheel with a grain size > #2000 needs to be used and the feed speed is reduced (< 0.01 mm/R), resulting in a 50% decrease in processing efficiency, and if R >0.20mm, the effective thickness of the cutting edge increases, weakening sharpness (e.g., cutting force increases by 15% when r=0.3 mm).

In the practical case 1, when the cutting edge matching R=0.15 mm, the comprehensive performance is optimal (the strength is improved by 20 percent, and the cutting force is increased by 8 percent);

practical case 2:55 DEG edge if R >0.20mm, the cutting resistance exceeds the material yield strength, resulting in an increased work hardening.

Practical case 3 if R <0.10mm and angle <45 °, the test edge chipping risk index exceeds the critical value of 1.5.

Practical case 4 if R >0.20mm and angle >55 deg., the tool wear mechanism is changed from abrasive wear to adhesive wear, the life is shortened by 60%.

In summary, in step S8, the structure of "gradual change of edge angle+gradual change of R value" (e.g. transition from 45 ° to 55 °, and transition of R from 0.10mm to 0.20 mm) is adopted, so that the fatigue resistance can be further improved. Meanwhile, if PVD coating (such as TiAlN) is carried out on the cutting edge, R=0.15 mm can improve the adhesive force of the coating by 30%, and peeling failure is effectively restrained.

Example two

Referring to fig. 2 to 5, another important aspect of the present invention is that an electric clipper movable blade blank 1 is produced by the production process of the first embodiment, the movable blade blank 1 has the upper fixing section 11 and the lower sliding section 12, the upper fixing section 11 further has a positioning slot 111 and an assembly hole 112, the upper end surface of the lower sliding section 12 is formed with the unit tooth 131, and the lower end surface of the lower sliding section 12 has an acute angle slot 133 adapted to the unit tooth 131.

Example III

Referring to fig. 6-10, an injection molding mold is used for molding a moving blade blank 1 and meets the requirement in step S1 in the first embodiment, the injection molding mold comprises a male mold 2 and a female mold 3, the male mold 2 is provided with a parting core 21 and a main glue inlet groove 22, the female mold 3 is provided with a cavity 31 matched with the parting core 21, the male mold 2 is provided with a first protrusion 23, a square column insert 24 for molding a positioning groove 111 and a cylindrical insert 25 for molding an assembly hole 112, and the female mold 3 is provided with a second protrusion 32. The first protrusion 23 and the second protrusion 32 are matched with each other to form the unit teeth 131, the inter-tooth grooves 132, and the acute angle grooves 133, so that the injection molding die can directly mold the moving blade blank of the original form.

It is particularly emphasized that the injection molding die also has a molding runner 4, the molding runner 4 being physically spaced from the main molding slot 22 for molding material (optionally engineering plastic, TPE). The sealing runner 4 comprises a glue inlet section 41, a detour section 42, a glue outlet trunk section 43 and a plurality of glue outlet branch sections 44 which are sequentially communicated from front to back, wherein the glue inlet section 41 is positioned in the middle of the lower side area of the male die 2, the glue inlet section 41 is provided with a secondary glue inlet slot 411, the detour section 42 is positioned on the female die 3, the detour section 42 is provided with 2 sections and symmetrically distributed on two sides of the cavity 31 so as to detour the cavity 31 of a product, the glue outlet trunk section 43 is positioned in the upper side area of the male die 2, the glue outlet branch sections 44 are positioned on the male die 2, and the glue outlet branch sections 44 are in one-to-one correspondence with the unit teeth 131 of the movable cutter blade blank 1.

The sealing flow channel 4 is designed to realize high-precision sealing of the unit teeth 131 of the knife blank 1 of the moving knife blade by combining temperature control, exhaust optimization and die movement cooperation through a four-section structure of single-point glue feeding, symmetrical detouring, secondary diversion and precise filling.

The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any simple modification, variation and equivalent structural changes of the above embodiment according to the technical matter of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. The production process of the movable blade blank is characterized by comprising:

S1. Make a set of injection molding molds;

S2, preparing the composite raw material, mixing and kneading at 170±5°C and pelletizing and drying to obtain 5±2mm composite raw material particles;

S3, placing the injection molding mold into a precision injection molding machine, then adding the particles of the composite raw material into the precision injection molding machine to manufacture a movable blade blank (1) through an injection molding process, wherein the movable blade blank (1) comprises an upper fixed section (11) and a lower sliding section (12), and the lower sliding section (12) has a tooth-shaped portion (13), the tooth-shaped portion (13) comprises a plurality of unit teeth (131), and inter-tooth grooves (132) are formed between adjacent unit teeth (131);

S4, performing an in-mold sealing treatment on the lower sliding section (12) of the movable blade blank (1) to form a sealing layer (14);

S5, placing the movable blade blank (1) on a ceramic plate, and then placing the entire blade blank into a degreasing furnace for degreasing;

S6. The degreased movable blade blank (1) is placed in a sintering furnace for high-temperature sintering, and the shrinkage rate during sintering is 16.5±0.5%;

S7, placing the sintered movable blade blank (1) into a heat treatment furnace for heat treatment and hardening;

S8, forming a sliding movable blade edge by grinding the toothed portion (13) to obtain a finished movable blade blank (1);

In step S2, the composite raw material is a combination of metal powder and a binder, and the weight ratio of the metal fusion powder to the binder is 10.6:1;

The metal fusion powder comprises the following components by weight percentage: 85% to 95% of 440C stainless steel or M2 steel metal powder, and 15% to 5% of aluminum oxide powder or zirconium oxide powder;

The binder comprises the following components by weight percentage: polyoxymethylene accounts for 81.2%±1%; high-density polyethylene accounts for 7.1%±1%; styrene-acrylonitrile copolymer accounts for 4.6%±1%; and antioxidant 1010 accounts for 7.1%±1%.

2. The production process of the movable blade blank (1) according to claim 1 is characterized in that: in step S3, the thickness of the movable blade blank (1) obtained is less than or equal to 3 mm ± 1‰.

3. The production process of the movable blade blank (1) according to claim 1 is characterized in that: in step S4, the thickness T of the sealant on the lower sliding section (12) of the movable blade blank (1) is greater than 0.25 mm, and the depth H of the inter-tooth groove (132) after the sealant is greater than or equal to 0.15 mm.

4. The production process of the movable blade blank (1) according to claim 1 is characterized in that: in step S5, the degreasing temperature is 90-120°C, the degreasing medium is oxalic acid, and the degreasing time is 6-10 hours.

5. The production process of the movable blade blank (1) according to claim 1, characterized in that: in step S6, the first stage sintering temperature is increased from room temperature to 600°C, and the first stage sintering time lasts for 5 to 6 hours;

The second stage sintering temperature rises from 600°C to 1050°C, and the second stage sintering time lasts for 6 to 8 hours;

The sintering temperature in the third stage increases from 1050°C to 1300°C, and the sintering time in the third stage lasts for 8 to 10 hours;

The sintering temperature in the fourth stage drops from 1300°C to 1100°C, and the sintering time in the fourth stage lasts for 5 to 6 hours;

The sintering temperature in the fifth stage drops from 1100° C. to room temperature, and the sintering time in the fifth stage lasts for 3 to 5 hours.

6. The production process of the movable blade blank (1) according to claim 1 is characterized in that: in step S7, the heat treatment temperature is set at 1045-1055°C, and the hardness of the movable blade blank (1) obtained after the heat treatment is HRC61-65; then the movable blade blank (1) is tempered, and the hardness of the movable blade blank (1) obtained after the tempering treatment is HRC57-60.

7. The production process of the movable blade blank (1) according to claim 1 is characterized in that: in step S8, the angle of the movable blade edge formed by the grinding process is 45°~55°, and the movable blade edge has a circular chamfer (R)R, and the radius of the circular chamfer (R)R is 0.10-0.20mm.

8. A movable blade blank (1) for an electric hair clipper, characterized in that: it is made using the production process of the movable blade blank (1) as described in any one of claims 1 to 6, the movable blade blank (1) has an upper fixed section (11) and a lower sliding section (12), the upper fixed section (11) also has a positioning groove (111) and an assembly hole (112), the upper end surface of the lower sliding section (12) is formed with the unit teeth (131), and the lower end surface of the lower sliding section (12) has an acute-angle groove (133) adapted to the unit teeth (131).

9. An injection molding mold, used for molding the movable blade blank (1) as claimed in claim 8, characterized in that it comprises a male mold (2) and a female mold (3), the male mold (2) having a parting core (21) and a main glue feeding groove (22), and the female mold (3) having a cavity (31) adapted to the parting core (21);

The male mold (2) has a first protrusion (23), a square column insert (24) for forming a positioning groove (111), and a cylindrical insert (25) for forming an assembly hole (112);

The female mold (3) has a second protrusion (32).

10. The injection molding die according to claim 9, characterized in that: the injection molding die further comprises a sealing glue flow channel (4), the sealing glue flow channel (4) comprising a glue inlet section (41), a bypass section (42), a glue outlet main section (43) and a plurality of glue outlet branch sections (44) which are sequentially connected from front to back;

The glue feeding section (41) is located in the middle of the lower area of the male mold (2), and the glue feeding section (41) has a secondary glue feeding groove (411);

The detour section (42) is located on the female mold (3), and the detour section (42) has two sections and is symmetrically distributed on both sides of the cavity (31);

The glue outlet trunk section (43) is located in the upper area of the male mold (2);

The glue outlet diverging section (44) is located on the male mold (2), and the glue outlet diverging section (44) corresponds one to one with the unit teeth (131) of the movable blade blank (1).