Preparation method of complex special-shaped head-replaceable milling cutter

Abstract

The invention relates to the technical field of intelligent manufacturing equipment industry, and discloses a preparation method of a complex special-shaped head-replaceable milling cutter, which comprises the following steps: step 1, preparing binder phase powder: adopting Co, Ni and Fe elements, adding Al powder or Ti powder or Cr powder, and mixing; step 2, mixing the binding phase powder with a hard alloy to prepare hard alloy composite powder, and mixing the hard alloy composite powder with an organic polymer material to prepare a hard alloy feed; 3, establishing a milling cutter three-dimensional model, and converting the milling cutter three-dimensional model into a multi-layer two-dimensional structure diagram; 4, the hard alloy feed is put into a stock bin of extrusion type preparation equipment, layer-by-layer preparation forming is carried out according to preparation parameters, and a green body is obtained; 5, the green body is subjected to degreasing treatment, and a milling cutter sample is prepared; and step 6, performing thermal degreasing on the milling cutter sample, performing vacuum sintering, and performing furnace cooling to obtain the head-replaceable milling cutter. The service performance of the milling cutter is effectively improved, the production steps of the milling cutter are simplified, and personalized production of the milling cutter is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing equipment manufacturing, and in particular to a method for preparing a complex special-shaped replaceable head milling cutter. Background Art

[0002] Interchangeable head milling cutters are a typical type of complex-configuration cemented carbide cutting tools. Compared with traditional solid carbide slot milling cutters, interchangeable head milling cutters have the advantages of flexible operation and long service life due to their modular design. At the same time, with the rapid development of the current manufacturing industry and the increasing demand for difficult-to-cut materials such as nickel-based and titanium-based alloys, complex-configuration cemented carbide cutting tools with high cutting force and excellent chip removal capabilities have received increasing attention. However, the current preparation methods of interchangeable head milling cutters are mainly die-forming and sintering densification, but due to mold limitations, it is often impossible to directly form complex-configuration interchangeable head milling cutter products, and a large amount of post-processing processing is required, resulting in low material utilization during the preparation of the interchangeable head milling cutter, and a large amount of processing may cause microcracks inside the milling cutter, affecting its service performance.

[0003] In recent years, the development of integrated forming of additive manufacturing technology has provided a new way for the customized preparation of complex configuration products. Additive manufacturing is an advanced digital manufacturing technology that uses computer control to stack materials layer by layer from bottom to top to obtain the final product. Since the external shape and internal component distribution of the product are not restricted by the mold, it has significant advantages in the preparation of cemented carbide parts with complex geometric configurations that are difficult or impossible to prepare by compression molding.

[0004] However, although additive manufacturing technology has solved the problem of being unable to produce parts with complex configurations due to mold limitations, and the parts produced by it can also meet general production needs, it is currently difficult to meet similar requirements for high cutting force and excellent cutting removal capabilities, resulting in the difficulty in improving the performance of existing exchangeable head milling cutters, resulting in poor service performance and affecting production efficiency. Summary of the invention

[0005] The present invention aims to provide a method for preparing a complex and special-shaped replaceable head milling cutter, so as to solve the problem that the replaceable head milling cutters produced in the prior art are difficult to meet high performance requirements, which affects the service performance of the replaceable head milling cutters.

[0006] To achieve the above purpose, the present invention adopts the following technical scheme, a method for preparing a complex and special-shaped replaceable head milling cutter. This scheme prepares a medium / high entropy alloy bonding phase with a small number of principal elements to obtain a cemented carbide feed with a unique organizational structure and excellent mechanical properties, and prepares it layer by layer through extrusion additive manufacturing, overcoming the problem that the traditional molding method is difficult to prepare a milling cutter with a complex configuration, and relatively simply realizes the preparation of a high-performance replaceable head milling cutter, improves the service performance of the replaceable head milling cutter, and realizes the personalized production of the replaceable head milling cutter. The preparation method of the replaceable head milling cutter includes the following steps:

[0007] Step 1, preparing a bonding phase powder: using Co, Ni, Fe elements, and adding Al powder or Ti powder or Cr powder, and mixing them, wherein the mass ratio of the Co, Ni, and Fe elements is Co: Ni: Fe = 3-6: 2-4: 1-5, and the particle size range of the Al powder or Ti powder or Cr powder is 1-4 μm;

[0008] Step 2, preparing cemented carbide feed: mixing the binder phase powder prepared in step 1 with cemented carbide to prepare cemented carbide composite powder, and mixing the cemented carbide composite powder with an organic polymer material to prepare cemented carbide feed;

[0009] Step 3, establishing a three-dimensional model of the milling cutter according to the structure of the replaceable head milling cutter, and converting the three-dimensional model into a multi-layer two-dimensional structure diagram;

[0010] Step 4, putting the cemented carbide feed into the silo of the extrusion preparation equipment, setting the preparation parameters according to the structural requirements, and preparing and molding layer by layer according to the multi-layer two-dimensional structure diagram to obtain a green body;

[0011] Step 5, degreasing the obtained green body to obtain a milling cutter sample;

[0012] Step 6, subjecting the degreased milling cutter sample to thermal degreasing treatment and vacuum sintering, and obtaining a replaceable head milling cutter after cooling in the furnace.

[0013] Furthermore, the cemented carbide is a medium / high entropy alloy bonding phase cemented carbide; wherein the mass fraction of the bonding phase powder in the cemented carbide composite powder is 6-10%, and the mass fraction of the cemented carbide is 90-94%.

[0014] Furthermore, the organic polymer material includes filler, skeleton, plasticizer and surfactant, and the corresponding mass ratios are 50-75:15-35:3-7:1-6. The surfactant ensures good wettability of the feed and the composite powder, the plasticizer and filler ensure stable flow during extrusion, and a small amount of skeleton material ensures that the green body still has good strength after degreasing to maintain the three-dimensional shape. The skeleton material will be removed in the sintering temperature rising process through thermal degreasing.

[0015] Furthermore, the filler includes at least one of solid paraffin, liquid paraffin, and microcrystalline wax; the skeleton includes at least one of vegetable oil, high-density polyethylene, low-density polyethylene, polypropylene, and ethylene-vinyl acetate copolymer; the plasticizer includes at least one of dioctyl phthalate, dibutyl phthalate, tricresyl phosphate, and tributyl citrate; and the surfactant includes at least one of stearic acid and oleic acid.

[0016] Furthermore, in step 5, n-heptane is used as a degreasing solvent, and degreasing is performed at 50-70°C for 20-30 hours to obtain a degreasing replaceable head milling cutter sample. Among them, too low a degreasing temperature and too short a degreasing time will lead to incomplete degreasing; an increase in the degreasing temperature will accelerate the degreasing rate, and too high a temperature will easily cause bubbling and cracking of the green body; and too long a degreasing time will affect the degreasing efficiency.

[0017] Furthermore, in step 6, the degreased milling cutter sample is placed in a vacuum furnace, and the temperature is slowly raised to 550°C using a H2 atmosphere furnace with a flow rate of 50L / min, and kept warm for 1 hour for thermal degreasing; then, the temperature is continuously raised to 1400-1500°C in a vacuum state, and 3-6 bar high-pressure argon gas is introduced and kept warm for 20-50 minutes for vacuum sintering.

[0018] Furthermore, the preparation parameters include nozzle size, preparation layer thickness, extrusion temperature, preparation platform temperature and filling flow rate.

[0019] Furthermore, the nozzle size is 0.1-0.8 mm; the preparation layer thickness is 0.1-0.2 mm; the extrusion temperature is 120-140° C.; the preparation platform temperature is 70-100° C.; and the filling flow rate is 50-100%.

[0020] Furthermore, it also includes filling speed, routing width, upper and lower layer routing direction, and single-layer routing method.

[0021] Furthermore, the molar percentage of each element in the bonding phase powder is 5% to 35%, so that the alloy has significant lattice distortion and solid solution strengthening characteristics, as well as excellent high temperature mechanical properties.

[0022] The principles and advantages of this solution are:

[0023] The current preparation methods of replaceable head milling cutters are mainly compression molding and sintering densification. However, due to mold limitations, it is often impossible to directly form replaceable head milling cutter products with complex structures. It is necessary to rely on a large amount of post-processing, resulting in low material utilization in the milling cutter preparation process. In addition, a large amount of processing may cause micro cracks inside the milling cutter, affecting its service performance.

[0024] In order to overcome the above problems, a new additive manufacturing technology is proposed. The traditional cemented carbide tool matrix mainly uses Co as the bonding phase and WC as the hard phase. Due to the characteristics of metal Co's easy softening at high temperature and poor oxidation resistance, the corrosion resistance and high temperature performance of WC-Co cemented carbide are limited, and it is difficult to adapt to harsh environments such as strong acid, strong alkali, and high temperature. Faced with the rapid development of modern industry, the requirements for cemented carbide tools are increasing. At the same time, considering the shortage of some metal resources and related environmental health issues, even if additive manufacturing technology is used for production, the traditional cemented carbide tool matrix material can only meet the general tool performance requirements, and it is difficult to improve the comprehensive performance of the replaceable head milling cutter, and it is impossible to achieve higher service performance and meet higher market demands.

[0025] At present, medium / high entropy alloys are used as cemented carbide binders, which show better hardness, fracture toughness, corrosion resistance and high-temperature oxidation resistance than Co binder cemented carbide. Medium / high entropy alloys are a type of multi-principal alloys, composed of five or more elements in almost equal percentages. These alloy structures usually have obvious lattice distortion and solid solution strengthening characteristics, so they have unique structures and excellent high-temperature mechanical properties. In order to further improve the performance of medium / high entropy alloys, the existing technology often adopts the method of adding elements with corresponding properties and adjusting the corresponding element ratio to achieve this. However, if the number of principal elements is too large, it will lead to more serious lattice distortion and element supersaturation segregation of medium / high entropy alloys, making their toughness lower and difficult to meet the strength and toughness requirements required for high-temperature cutting. However, if the number of principal elements is too small, the diffusion hysteresis effect of medium / high entropy alloys will be weakened, and the abnormal growth of WC grains will increase, resulting in a decrease in the hardness and high-temperature strength of the cemented carbide, and it will be difficult to meet the performance requirements. Therefore, in the preparation of cemented carbide, at least four or more elements will be used to ensure the performance requirements. For example, the patent with publication number CN104372230A discloses a solution containing at least five elements such as Ni, Fe, Co, Cr, and Al to improve the performance of cemented carbide.

[0026] In the prior art, in order to improve the comprehensive ability of cemented carbide, the general method is to further add elements with corresponding excellent performance, without considering the reverse reduction of synthetic elements. However, this scheme breaks away from the inherent thinking of the conventional preparation method of increasing the number of principal element alloys, but adopts the method of reducing the number of principal elements, and uses 3 to 4 kinds of critical point minor principal elements as constituent elements to prepare the cemented carbide matrix. The reason is that we found that after adding too many principal elements, it will cause serious lattice distortion and element supersaturation segregation of medium / high entropy alloys, making their toughness lower and difficult to meet the strength and toughness requirements required for high-temperature cutting. Therefore, 5 or more elements are often selected. The reason why this scheme can achieve 3 to 4 minor principal elements is that this scheme is configured in combination with reasonable component mass ratio parameters to prepare bonding phase powder with better mechanical properties and improve the service performance of the milling cutter. In addition, through the layer-by-layer manufacturing method of extrusion additive manufacturing and the characteristics of dual nozzles, the production process of complex configuration milling cutters is simplified, and the preparation of high-performance exchangeable head milling cutters can be realized relatively simply. The internal and external structures that are difficult to prepare by traditional molding methods can be flexibly constructed. In the actual production process, the local material composition and density distribution can be flexibly adjusted according to actual conditions, thereby realizing the personalized production of medium / high entropy alloy bonding phase exchangeable head milling cutters and improving overall production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a schematic flow chart of a method for preparing a complex special-shaped replaceable head milling cutter.

[0028] Figure 2 The invention discloses a metallographic structure at a low magnification of the edge portion of an exchangeable head milling cutter produced by a method for preparing a complex special-shaped exchangeable head milling cutter.

[0029] Figure 3 The present invention discloses a method for preparing a complex and special-shaped replaceable head milling cutter and a microstructure of the replaceable head milling cutter under high magnification. DETAILED DESCRIPTION

[0030] The following is further described in detail through specific implementation methods:

[0031] Example 1

[0032] As attached Figure 1 As shown, this scheme aims to address the limited flexibility and large machining allowance of traditional molded structures, as well as the difficulty of metal bonding phase cemented carbide to meet the use requirements of cemented carbide tools in complex service environments. Medium / high entropy alloys are used as cemented carbide bonding phases, and extrusion additive manufacturing is combined to prepare new complex and special-shaped exchangeable head milling cutters, thereby improving the overall service performance of the exchangeable head milling cutters.

[0033] In this embodiment, additive manufacturing (3D printing) technology is an advanced digital manufacturing technology. Materials are stacked layer by layer from bottom to top under computer control to obtain the final product. The external shape and internal component distribution of the product are not restricted by the mold, so that cemented carbide parts with complex geometric configurations that are difficult or impossible to prepare by compression molding can be prepared.

[0034] Powder extrusion 3D printing (PEP) is an additive manufacturing technology based on the traditional powder metallurgy forming-degreasing-sintering process. It heats the mixed metal powder and polymer binder into a molten fluid slurry, selectively extrude it through a nozzle to form a complex structure green body, and then obtains a sintered dense body through a post-processing process that is highly compatible with the traditional one. It is suitable for high-density additive manufacturing of high-melting point materials such as cemented carbide. At the same time, PEP also has the characteristics of multiple extrusion heads, which can easily realize the selective distribution of material components and density, and then multiple control of sintering shrinkage, which is more conducive to the additive manufacturing of highly complex structure cemented carbide products. In this embodiment, the preparation method is based on extrusion additive manufacturing and includes the following steps:

[0035] S1, preparation of bonding phase powder:

[0036] The bonding phase is composed of 3 to 4 elements, among which the main elements are Co powder, Ni powder and Fe powder, and the mass ratio of the components is Co:Ni:Fe=3 to 6:2 to 4:1 to 5. Co powder, Ni powder and Fe powder are mixed. At the same time, one of Al powder, Ti powder or Cr powder is added. The particle size range of the three powders is 1 to 4 μm, accounting for 2 to 13 wt.%. The molar ratio of the four element powders is 5% to 35%. The selected element powders are evenly mixed using a three-dimensional mixer to obtain bonding phase powder.

[0037] That is, the elemental composition of the obtained bonding phase powder is divided into three cases: (1) Co powder, Ni powder, Fe powder and Al powder; (2) Co powder, Ni powder, Fe powder and Ti powder; (3) Co powder, Ni powder, Fe powder and Cr powder. The multi-principal element design makes this type of alloy have significant lattice distortion and solid solution strengthening characteristics, as well as excellent high-temperature mechanical properties, thereby ensuring that the performance requirements are met, and avoiding the weakening of the diffusion hysteresis effect of medium / high entropy alloys and the increase of abnormal growth of WC grains, ensuring the hardness and high-temperature strength of cemented carbide. In addition, the use of medium / high entropy alloys instead of Co as the bonding phase of cemented carbide shows better hardness, fracture toughness, corrosion resistance and high-temperature oxidation resistance than Co bonding phase cemented carbide.

[0038] Of course, in another embodiment, the bonding phase powder can be prepared by mixing the three main elements Co powder, Ni powder and Fe powder, that is, the elemental composition of the bonding phase powder only includes Co powder, Ni powder and Fe powder. After experimental comparison, its hardness is better than that of the quaternary component, but the toughness is slightly reduced. According to the performance requirements of different milling cutters, a better bonding phase powder preparation method can be relatively selected to meet different processing requirements.

[0039] S2, preparing cemented carbide feed, comprises the following sub-steps:

[0040] S2.1, prepare cemented carbide composite powder: In this embodiment, the cemented carbide is a medium / high entropy alloy bonding phase cemented carbide powder, and the medium / high entropy alloy bonding phase cemented carbide powder is mixed with the bonding phase powder prepared in S1, wherein the mass fraction of the bonding phase powder is 6-10%, and the mass fraction of the medium / high entropy alloy bonding phase cemented carbide powder is 90-94%. A cemented carbide composite powder is obtained. In this embodiment, a cemented carbide powder with a particle size of 0.8-1.2 μm is selected.

[0041] S2.2, preparing cemented carbide feedstock: after mixing cemented carbide composite powder with organic polymer material, cemented carbide feedstock is obtained by mixing, kneading and granulating.

[0042] In this embodiment, the organic polymer material includes a filler, a skeleton, a plasticizer and a surfactant, and the corresponding mass ratios are filler: skeleton: plasticizer: surfactant = 50-75: 15-35: 3-7: 1-6.

[0043] The filler includes at least one of solid paraffin (PW), liquid paraffin (LPW), and microcrystalline wax (MW); in this embodiment, preferably, solid paraffin (PW) and microcrystalline wax (MW) are mixed.

[0044] The skeleton includes at least one of vegetable oil (EO), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), and ethylene-vinyl acetate copolymer (EVA); in this embodiment, it is preferably a mixture of high-density polyethylene (HDPE) and ethylene-vinyl acetate copolymer (EVA). The skeleton material can ensure that the green body still has better strength after degreasing to maintain a three-dimensional shape, so that it can withstand the stress of subsequent processing and treatment, and help maintain the desired shape and size. At the same time, the skeleton material will be removed during the thermal degreasing process of the sintering temperature rise, ensuring that the final performance of the milling cutter will not be affected by the residue of the skeleton material.

[0045] The plasticizer includes at least one of dioctyl phthalate (DOP), dibutyl phthalate (DBP), tricresyl phosphate (TCP), and tributyl citrate (TBC); in this embodiment, dioctyl phthalate (DOP) is preferred. The plasticizer and filler can ensure the flow stability and uniformity during the extrusion process, reduce the extrusion pressure, improve the extrusion efficiency, and ensure the consistency and quality of the milling cutter structure.

[0046] The surfactant includes at least one of stearic acid (SA) and oleic acid. In this embodiment, stearic acid (SA) is preferred. The surfactant is used to ensure good wettability of the feed and the composite powder, thereby improving mixing efficiency and uniformity.

[0047] S3, two-dimensional structure diagram construction:

[0048] A three-dimensional model of the milling cutter is established according to the structure of the exchangeable head milling cutter, and the three-dimensional model is converted into a multi-layer two-dimensional structural diagram.

[0049] In this embodiment, according to the target three-dimensional structure of the prepared milling cutter, the three-dimensional structure is modeled and converted into a multi-layer two-dimensional structure diagram recognizable by the extrusion preparation equipment through slicing software. In this embodiment, the extrusion preparation equipment can use a three-dimensional printing device.

[0050] S4, green preparation:

[0051] The hard alloy feed prepared in S2 is placed in the silo of the extrusion preparation equipment. The preparation parameters are set according to the structural requirements, and the green body is prepared layer by layer according to the multi-layer two-dimensional structure diagram.

[0052] The preparation parameters include nozzle size, preparation layer thickness, extrusion temperature, preparation platform temperature and filling flow rate. The nozzle size and preparation layer thickness are selected according to the target structure accuracy, and the preparation parameters such as extrusion temperature, preparation platform temperature and filling flow rate are set. The modeling slice file is imported to prepare for layer-by-layer preparation and printing.

[0053] In this embodiment, when extrusion preparation printing is performed, a nozzle size of 0.1 to 0.8 mm is generally selected; when preparing printing, the thickness of a single layer is 0.1 to 0.2 mm, the extrusion temperature is set to 120 to 140°C, the preparation platform temperature is set to 70 to 100°C, and the filling flow rate is set to 50 to 100%. Other conditional parameters include: filling speed 10 to 40 mm / s, the routing width is consistent with the nozzle size, the routing direction of the upper and lower layers is [0, 90°], and the single-layer routing method is one of straight line, sawtooth, and concentric circle.

[0054] S5, degreasing treatment:

[0055] The obtained green body is degreased to obtain a milling cutter sample. In this embodiment, the complex and special-shaped exchangeable head milling cutter green body is degreased, and n-heptane is used as the degreasing solvent. The green body is degreased at 50-70°C for 20-30 hours to remove PW, MW, and SA to obtain a degreased exchangeable head milling cutter sample. In this embodiment, degreasing at 50°C for 24 hours can be used to ensure the degreasing effect. Among them, if the degreasing temperature is too low and the degreasing time is too short, incomplete degreasing will result; and an increase in the degreasing temperature will accelerate the degreasing efficiency. Too high a temperature will easily cause bubbling and cracking of the green body; too long a degreasing time will affect the degreasing efficiency.

[0056] S6, thermal debinding and sintering treatment, includes the following sub-steps:

[0057] S6.1, thermal degreasing treatment: thermal degreasing treatment is performed on the degreased milling cutter sample. In this embodiment, the milling cutter sample degreased in S5 is placed in a vacuum furnace, and a H2 atmosphere furnace with a flow rate of 50L / min is used to slowly increase the temperature to 550°C and keep the temperature for 1 hour for thermal degreasing to completely remove the polymer binder.

[0058] S6.2, sintering treatment: After thermal debinding, the temperature is continuously raised to 1400-1500°C in a vacuum state, and 3-6 bar high-pressure argon is introduced to keep the temperature for 20-50 minutes for vacuum sintering. Then the milling cutter sample is cooled in the furnace to obtain a complex special-shaped replaceable head milling cutter with a medium / high entropy alloy bonding phase in additive manufacturing. Figure 2 , Attachment Figure 3 The following are the low-magnification and high-magnification metallographic structure diagrams of the complex special-shaped replaceable head milling cutter. It can be seen from the figure that the milling cutter prepared by this method has a uniform distribution of WC hard phase, no abnormal growth and dense structure. According to the mechanical properties test, the hardness of the milling cutter prepared by this scheme is 92.4HRA and the fracture toughness is 16.8MPa·m 1 / 2 The physical and mechanical performance technical indicators of the two phases are better than those of the existing technical products. It should be noted that due to the shape and size limitations, the bending strength test was not performed in this embodiment. The milling cutter prepared by the present invention is used for 201 stainless steel rough milling plane cutting, and its life is increased by more than 1.2 times compared with the existing YG10 benchmark product.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that in S4, the preparation parameters are set as follows: nozzle size is 0.4 mm, layer thickness is 0.15 mm, extrusion temperature is 160° C. (i.e., exceeding the setting range), filling flow is 90%, and printing platform temperature is 80° C. Then, the cemented carbide feed is placed in the silo of the extrusion preparation equipment, and printing is performed according to the preset parameters.

[0061] The printing progressed well in the early stage. As the number of printing layers increased, a lot of feed remained at the end of the nozzle printing path of each layer. By the middle of sample preparation, the residue gathered into small balls and collapsed due to the back and forth squeezing of the nozzle, resulting in the scrapping of the sample.

[0062] It can be concluded that the preparation parameters set in this scheme are suitable for the stable preparation of the milling cutter with excellent high-temperature mechanical properties in this embodiment, which effectively improves the service performance of the milling cutter while ensuring production stability, quality and efficiency.

[0063] The current preparation methods of replaceable head milling cutters are mainly die-pressing and sintering densification. However, due to mold limitations, it is often impossible to directly form replaceable head milling cutter products with complex configurations. A large amount of post-processing is required, resulting in low material utilization during the preparation of the milling cutter, and a large amount of processing may cause micro cracks inside the milling cutter, affecting its service performance. Existing materials suitable for additive manufacturing, such as WC-Co cemented carbide, are limited in corrosion resistance and high temperature performance due to the characteristics of metal Co being easy to soften at high temperatures and having poor oxidation resistance. It is difficult to adapt to harsh environments such as strong acids, strong alkalis, and high temperatures, resulting in the performance of replaceable head milling cutters being difficult to meet the growing market demand.

[0064] In this embodiment, the method of reducing the number of principal elements is adopted, and 3 to 4 kinds of minor principal elements are used as constituent elements to prepare the bonding phase, breaking away from the inherent method of preparing the principal element alloy by the number of principal elements. At the same time, combined with the configured component mass ratio parameters, the problem of excessive number of principal elements in medium / high entropy alloys, resulting in serious lattice distortion and element supersaturation segregation, and causing lower toughness, is avoided; at the same time, the problem of a small number of principal elements, weakened diffusion hysteresis effect of medium / high entropy alloys, increased abnormal growth of WC grains, and reduced hardness and high-temperature strength of cemented carbide is overcome, thereby effectively improving the comprehensive performance of cemented carbide materials used for milling cutter preparation.

[0065] This scheme utilizes the unique organization and excellent mechanical properties of medium / high entropy alloys, as well as the layer-by-layer manufacturing and dual-nozzle characteristics of extrusion additive manufacturing, to relatively simply realize the preparation of high-performance medium / high entropy alloy binder phase exchangeable head milling cutters, and can flexibly construct internal and external structures that are difficult to prepare by traditional molding methods, as well as adjust the local material composition and density distribution of the milling cutter according to actual production, thereby realizing the personalized production of medium / high entropy alloy binder phase exchangeable head milling cutters.

[0066] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a complex special-shaped replaceable head milling cutter, characterized in that: The following steps are involved: Step 1, preparing a bonding phase powder: using Co, Ni, Fe elements, and adding Al powder or Ti powder or Cr powder, and mixing them, wherein the mass ratio of the Co, Ni, and Fe elements is Co: Ni: Fe = 3-6: 2-4: 1-5, and the particle size range of the Al powder or Ti powder or Cr powder is 1-4 μm; Step 2, preparing cemented carbide feed: mixing the binder phase powder prepared in step 1 with cemented carbide to prepare cemented carbide composite powder, and mixing the cemented carbide composite powder with an organic polymer material to prepare cemented carbide feed; Step 3, establishing a three-dimensional model of the milling cutter according to the structure of the replaceable head milling cutter, and converting the three-dimensional model into a multi-layer two-dimensional structure diagram; Step 4, putting the cemented carbide feed into the silo of the extrusion preparation equipment, setting the preparation parameters according to the structural requirements, and preparing and molding layer by layer according to the multi-layer two-dimensional structure diagram to obtain a green body; Step 5, degreasing the obtained green body to obtain a milling cutter sample; Step 6, subjecting the degreased milling cutter sample to thermal degreasing treatment and vacuum sintering, and obtaining a replaceable head milling cutter after cooling in the furnace.

2. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 1, characterized in that: The cemented carbide is a medium / high entropy alloy bonding phase cemented carbide; wherein the mass fraction of bonding phase powder in the cemented carbide composite powder is 6-10%, and the mass fraction of cemented carbide is 90-94%.

3. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 1, characterized in that: The organic polymer material comprises a filler, a skeleton, a plasticizer and a surfactant, and the corresponding mass ratios are 50-75:15-35:3-7:1-6 respectively.

4. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 3, characterized in that: The filler includes at least one of solid paraffin, liquid paraffin, and microcrystalline wax; the skeleton includes at least one of vegetable oil, high-density polyethylene, low-density polyethylene, polypropylene, and ethylene-vinyl acetate copolymer; the plasticizer includes at least one of dioctyl phthalate, dibutyl phthalate, tricresyl phosphate, and tributyl citrate; the surfactant includes at least one of stearic acid and oleic acid.

5. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 1, characterized in that: In step 5, n-heptane is used as a degreasing solvent, and degreasing is performed at 50 to 70° C. for 20 to 30 hours to obtain a degreased exchangeable head milling cutter sample.

6. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 1, characterized in that: In step 6, the degreased milling cutter sample is placed in a vacuum furnace, and the temperature is slowly raised to 550°C using a H2 atmosphere furnace with a flow rate of 50L / min, and kept warm for 1 hour for thermal degreasing; then, the temperature is continuously raised to 1400-1500°C in a vacuum state, and 3-6 bar high-pressure argon gas is introduced and kept warm for 20-50 minutes for vacuum sintering.

7. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 1, characterized in that: The preparation parameters include nozzle size, preparation layer thickness, extrusion temperature, preparation platform temperature and filling flow rate.

8. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 7, characterized in that: The nozzle size is 0.1-0.8 mm; the preparation layer thickness is 0.1-0.2 mm; the extrusion temperature is 120-140° C.; the preparation platform temperature is 70-100° C.; and the filling flow rate is 50-100%.

9. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 7, characterized in that: It also includes filling speed, routing width, routing direction of upper and lower layers, and single-layer routing method.

10. The method for preparing a complex and special-shaped replaceable head milling cutter according to claim 1, characterized in that: The molar percentage of each element in the bonding phase powder is 5% to 35%.

Images