A heterogeneous diamond grinding wheel and a method for manufacturing the same

Abstract

This invention discloses a heterogeneous diamond grinding wheel with an irregular interface structure and its preparation method. The working layer of the diamond grinding wheel is a metal-based diamond composite material, and the matrix is ​​steel. The preparation method involves designing heterogeneous models such as square waves, sawtooth, wave patterns, and layered structures; using a multi-material additive manufacturing technology based on laser powder bed melting with simultaneous powder spreading and absorption, a stainless steel grinding wheel matrix and a diamond composite grinding wheel working layer are formed on the same plane, achieving 3D printing of the heterogeneous diamond grinding wheel. The heterogeneous diamond grinding wheel prepared by this invention not only achieves simultaneous forming of heterogeneous materials, but also exhibits a high-strength metallurgical bond between the diamond composite working layer and the steel matrix. Furthermore, the irregular interface structure alleviates residual stress at the grinding wheel interface, improving upon the drawback of low bonding strength caused by high residual stress at the interface of heterogeneous diamond grinding wheels.

Description

Technical Field

[0001] This invention belongs to the field of superhard materials technology. Specifically, it uses multi-material additive manufacturing technology to prepare a heterogeneous diamond grinding wheel with significantly reduced thermal residual stress and significantly enhanced structural stability by introducing a heterogeneous interface structure. Background Technology

[0002] Grinding is a primary method for precision / ultra-precision machining, enabling parts to achieve higher accuracy, surface integrity, and stringent manufacturing consistency. For example, difficult-to-machine materials such as ceramics and microcrystalline glass currently rely solely on grinding in industry. In recent years, with the application of superhard materials such as diamond and cBN, grinding and abrasive machining have become increasingly important in the field of mechanical manufacturing. Grinding wheels are the most important type of grinding tool in grinding. Superhard grinding wheels have a two-part structure: an outer abrasive ring, typically composed of superhard abrasive grains such as diamond or cBN bonded together with an adhesive, effectively cutting and reducing the workpiece during grinding; and an inner core, typically made of carbon steel, which connects the abrasive ring to the machine tool spindle and transmits torque to the grinding wheel's working area.

[0003] Because the abrasive ring working layer and the steel core matrix involve two different material systems, traditional manufacturing methods are generally step-by-step, with two common methods. The first method involves preparing the steel core matrix through forging or casting, then forming the abrasive ring through hot pressing and sintering, and finally bonding the abrasive ring to the matrix using adhesives. The second method involves first preparing the abrasive wheel matrix, and then directly sintering the abrasive ring onto the steel core matrix. Multi-material laser selective melting (SLM) additive manufacturing technology can distribute different materials to functionally distinct areas within a component, enabling assembly-free 3D printing and significantly simplifying production steps. However, the unique rapid melting process of SLM makes it easy for residual stress to accumulate inside the formed part, and the mismatch in thermophysical parameters between dissimilar materials further exacerbates interfacial residual stress. High interfacial residual stress can compromise the structural stability of the diamond grinding wheel. For example, the research results of the research group in the early stage, patents 2022109879254 and 2022114349224 involve one-piece molding, but in the early stage, no consideration was given to how to reduce the stress in the one-piece molded product. Summary of the Invention

[0004] Based on previous research, this invention is the first to attempt to release residual stress in heterogeneous grinding wheels through interface structure design.

[0005] The present invention provides a heterogeneous diamond grinding wheel, the structure of which is one of Scheme 1 or Scheme 2, wherein Scheme 1 is selected from one of the following sub-schemes;

[0006] Option 1-1

[0007] The heterogeneous diamond grinding wheel consists of a steel core matrix and a diamond composite working layer. The steel core matrix and the diamond composite working layer are formed using a 3D printing process. After forming, the diameter of the diamond grinding wheel is projected perpendicular to the diameter of the grinding wheel.

[0008] The interface between the steel core matrix and the diamond composite working layer has a square waveform.

[0009] Option 1-2

[0010] The heterogeneous diamond grinding wheel consists of a steel core matrix and a diamond composite working layer. The steel core matrix and the diamond composite working layer are formed using a 3D printing process. After forming, the diameter of the diamond grinding wheel is projected perpendicular to the diameter of the grinding wheel.

[0011] The interface between the steel core matrix and the diamond composite working layer is wavy.

[0012] Option 1-3

[0013] The heterogeneous diamond grinding wheel consists of a steel core matrix and a diamond composite working layer. The steel core matrix and the diamond composite working layer are formed using a 3D printing process. After forming, the diameter of the diamond grinding wheel is projected perpendicular to the diameter of the grinding wheel.

[0014] The interface between the steel core matrix and the diamond composite working layer is serrated.

[0015] Option 2

[0016] The heterogeneous diamond grinding wheel comprises a steel core matrix, a transition layer, and a diamond composite working layer. The steel core matrix, transition layer, and diamond composite working layer are formed using a 3D printing process. In the radial direction, the transition layer covers the steel core matrix, and the diamond composite working layer covers the transition layer. In the radial direction, the transition layer consists of alternating rings of material A and material B, and the transition layer, the steel core matrix, and the diamond composite working layer are concentric circles. The rings of material A and material B are also concentric circles. The material of material A is the same as that of the steel core matrix, and the material of material B is the same as that of the diamond composite working layer. The matrix is ​​in contact with the ring of material B, and the outermost ring of material A is in contact with the diamond composite working layer. Between the matrix and the diamond composite working layer, material B and material A layers are alternately arranged in a ring of material B / ring of material A.

[0017] As a preferred embodiment, the present invention provides a heterogeneous diamond grinding wheel, wherein the diamond composite working layer is composed of a binder and diamond micro powder, wherein the binder comprises the following components by mass percentage: Cu: 89-91 wt.%, Sn: 9-11 wt.%; and the diamond added in the diamond composite working layer is 12.5%-25% by volume.

[0018] As a preferred embodiment, the present invention provides a heterogeneous diamond grinding wheel with diamond microparticles having an average particle size of 40μm-90μm.

[0019] As a preferred embodiment, the present invention provides a heterogeneous diamond grinding wheel in which the steel core matrix is ​​made of one of the laser-formable tough structural steels such as 316L stainless steel, 304 stainless steel, and 17-4PH stainless steel.

[0020] As a preferred embodiment, this invention provides a heterogeneous diamond grinding wheel. In embodiment 1, the projection perpendicular to the diameter of the diamond grinding wheel is shown. The projection of the steel core substrate consists of a circular ring and a raised portion on the outer side of the ring. The raised portion has a square wave shape. The radius r of the circular ring is 15-25 mm, preferably 18-22 mm. The projection of the diamond grinding wheel is a circular ring with a radius R, where R is 60-100 mm, preferably 78-82 mm. Of course, the size of the grinding wheel can be freely adjusted according to the actual situation, depending on the size of the SLM substrate.

[0021] Preferably, this invention provides a heterogeneous diamond grinding wheel. When projected perpendicular to the diameter of the diamond grinding wheel, the interface between the steel core matrix and the diamond composite working layer exhibits a square wave pattern. The amplitude of the square wave is 5mm-20mm, and the trough of the square wave plus half the amplitude lies on a circle C. The radius of circle C, R' = r + D, is in mm, where D ranges from 2.5 to 10mm. The average peak width of the square wave is 0.3 to 0.6 times the amplitude of the square wave.

[0022] Preferably, in this invention, a heterogeneous diamond grinding wheel, when projected perpendicular to the diameter of the diamond grinding wheel, has a square-wave-shaped interface between the steel core matrix and the diamond composite working layer, the circumferential proportion of this interface in the square-wave structure region is... The range is 25% to 75%; where R' is the radius of circle C, l is the distance between two adjacent square waves on circle C, and ∑l is the sum of the distances between adjacent square waves on circle C.

[0023] As a preferred embodiment, this invention provides a heterogeneous diamond grinding wheel. In embodiment 1, the projection perpendicular to the diameter of the diamond grinding wheel consists of a circular ring and a raised portion on the outer side of the ring. The raised portion is wavy (i.e., the contact interface between the substrate and the working layer is a continuous tangent semicircle in opposite directions). The radius r of the circular ring is 15-25 mm, preferably 18-22 mm. The projection of the diamond grinding wheel is a circular ring with a radius R, where R is 60-100 mm, preferably 78-82 mm. Of course, the size of the grinding wheel can be freely adjusted according to the actual situation, depending on the size of the SLM substrate.

[0024] As a further preferred embodiment, the present invention provides a heterogeneous diamond grinding wheel in which, when projected perpendicular to the diameter of the diamond grinding wheel, the interface between the steel core matrix and the working layer of the diamond composite material is wavy. The interface shape between the matrix and the working layer is a continuous series of tangent semicircles in opposite directions, with each circle having the same radius r', and r' ranging from 2.5mm to 5mm. The trough of the semicircle with an amplitude of +1 / 2 is located on circle C, and the radius of circle C, R', is r + D in mm, where D ranges from 2.5mm to 5mm.

[0025] Preferably, in this invention, a heterogeneous diamond grinding wheel, when projected perpendicular to the diameter of the diamond grinding wheel, shows a wavy interface between the steel core matrix and the diamond composite working layer, the circumferential proportion of this interface within the wavy structure region is... The range is 25% to 75%; where R' is the radius of circle C, l is the distance between two adjacent semicircular waves on circle C, and ∑l is the sum of the distances between adjacent semicircular waves on circle C.

[0026] As a preferred embodiment, this invention provides a heterogeneous diamond grinding wheel. In embodiment 1, the projection perpendicular to the diameter of the diamond grinding wheel consists of a circular ring and a raised portion on the outer side of the ring. The raised portion is serrated (i.e., the contact interface between the substrate and the working layer is triangular). The radius r of the circular ring is 15-25 mm, preferably 18-22 mm. The projection of the diamond grinding wheel is a circular ring with a radius R, where R is 60-100 mm, preferably 78-82 mm. Of course, the size of the grinding wheel can be freely adjusted according to the actual situation, depending on the size of the SLM substrate.

[0027] As a further preferred embodiment, this invention provides a heterogeneous diamond grinding wheel. When projected perpendicular to the diameter of the diamond grinding wheel, the interface between the steel core matrix and the diamond composite working layer is serrated. The interface shape between the matrix and the working layer is a triangular wave with a apex angle of 5.625°-11.25° and an amplitude of 5-20 mm (i.e., the shortest distance from the apex of the triangular wave to the projected annulus of the steel core matrix is ​​5-20 mm). The trough of the triangular wave with an amplitude of +1 / 2 lies on circle C, where the radius of circle C is R' = r + D in mm, and D ranges from 2.5 to 10 mm. The circumferential proportion of the interface between the steel core matrix and the diamond composite working layer in the serrated structure region is... The range is 25% to 75%; where l is the distance between two adjacent triangles on circle C, and ∑l is the sum of the distances between adjacent triangles on circle C.

[0028] The square wave, wave, and sawtooth structures in Scheme 1 all increase the maximum interfacial contact area between heterogeneous materials, and the protruding structure of the working layer extending into the matrix weakens the transmission of stress to the weak areas of the matrix, thus achieving reasonable stress distribution and uniform interfacial stress.

[0029] As a preferred embodiment, in Scheme 2 of the present invention, a heterogeneous diamond grinding wheel is projected perpendicular to the diameter of the diamond grinding wheel. The projection of the diamond grinding wheel is a ring with a radius of R, where R is 60-100 mm, preferably 78-82 mm. The projection of the steel core matrix is ​​a ring with a radius of r, where r is 15-25 mm, preferably 18-22 mm. The projection of one layer of material B is a ring with a ring width of 1-8 mm. The projection of one layer of material A is a ring with a ring width of 1-5 mm. In this invention, the ring width refers to the difference between the outer diameter and the inner diameter of the ring.

[0030] As a preferred embodiment, in the heterogeneous diamond grinding wheel of the present invention, in Scheme 2, the contact interface between the matrix and the working layer consists of concentric annular bands of two materials alternatingly distributed, with each annular band having a width of 1-2 mm. The number of alternating concentric annular bands is 2N, where N is any integer between 1 and 20, preferably between 2 and 5.

[0031] In this invention, circle C and the grinding wheel base are concentric circles.

[0032] In Scheme 2, the stacked transition structure contains multiple alternating matrix layers and working layers. Each matrix layer is subjected to stress transmission from the working layers on both sides. When the ring width is small, the stresses of the working layers on both sides cancel each other out in the matrix layer. When the ring width is large, the stresses cancel each other out in the working layer. This structure with heterogeneous materials arranged in equal proportions can be equivalent to a buffer layer with stress release and strain coordination functions.

[0033] This invention discloses a method for preparing heterogeneous diamond grinding wheels, comprising the following steps:

[0034] Step 1:

[0035] The steel material powder for the matrix is ​​placed into the powder feeding cylinder in the forming cavity, and the diamond composite material powder is placed into the powder feeder in the forming cavity. The forming cavity is evacuated to an oxygen content of less than 0.1% and then flowing argon gas is introduced.

[0036] Step Two:

[0037] Create the matrix model and working layer model of the heterogeneous diamond grinding wheel, and import the matrix model and working layer model files into the SLM device respectively; or

[0038] Draw the matrix model, working layer model, and transition layer model of the heterogeneous diamond grinding wheel, and import the matrix model file, working layer model file, and transition layer model file into the SLM device respectively;

[0039] Step 3:

[0040] Laser scanning is performed using the base model file and working layer model file imported into the SLM device to form a heterogeneous diamond grinding wheel; or

[0041] Laser scanning is performed on the imported matrix model file, working layer model file, and transition layer model file from the SLM device to form a heterogeneous diamond grinding wheel.

[0042] In actual operation, steel powder is spread on the substrate through a powder spreading roller, the matrix model is extracted, and a single-layer matrix is ​​formed by laser scanning. Then, the excess steel powder on the substrate is removed by the built-in micro powder suction device. Next, the diamond composite powder is sent to the working layer model by the powder feeder. After the mixed powder is spread evenly by the powder spreading roller, the working layer model is extracted and a single-layer working layer is formed by laser scanning.

[0043] Through the above process, a single layer of heterogeneous materials within the same layer is formed. This process is repeated to complete the stacking of multiple layers and the formation of a diamond grinding wheel.

[0044] In this invention, binder powder and a certain volume percentage of diamond are mixed in a three-dimensional slow mixer for 3-6 hours. The diamond abrasive particles can be surface-metallized modified diamond powder.

[0045] This invention discloses a method for preparing heterogeneous diamond grinding wheels; during the forming of the steel core matrix, the laser power is controlled at 200-400W and the scanning speed is 600-1200mm / s.

[0046] This invention discloses a method for preparing heterogeneous diamond grinding wheels; during the forming of the working layer of diamond composite material, the laser power is controlled to be 120-180W, the scanning speed is 700-1100mm / s, and the layer thickness is 0.05mm-0.09mm.

[0047] This invention discloses a method for preparing heterogeneous diamond grinding wheels. When printing the transition layer designed in scheme 2, the laser power is controlled at 200-400W and the scanning speed at 600-1200mm / s when printing material layer A. When printing material layer B, the laser power is controlled at 120-180W, the scanning speed at 700-1100mm / s, and the layer thickness at 0.05mm-0.09mm.

[0048] This invention discloses a method for preparing a heterogeneous diamond grinding wheel; the average radial stress of the heterogeneous diamond grinding wheel is 25.4 MPa to 43.6 MPa.

[0049] Compared with the prior art, the significant advantages of this invention are:

[0050] (1) The heterogeneous diamond grinding wheel based on multi-material additive manufacturing proposed in this invention can achieve near-net-shape forming of steel core matrix and diamond composite working layer in one step compared with existing grinding wheel production methods, simplifying the manufacturing process.

[0051] (2) When the thermophysical properties of the matrix and abrasive ring materials of a conventional grinding wheel do not match, large residual thermal stress will be formed at the interface, causing a decrease in the strength of the grinding wheel structure. The present invention adopts an irregular interface structure, which can alleviate the residual stress at the interface, reduce the residual stress level in the structure, and improve the stability of the grinding wheel structure. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the heterogeneous diamond grinding wheel designed in Scheme 1-1 of the present invention;

[0053] Figure 2 This is a schematic diagram of the heterogeneous diamond grinding wheel designed in Scheme 1-2 of the present invention;

[0054] Figure 3 This is a schematic diagram of the heterogeneous diamond grinding wheel designed in schemes 1-3 of the present invention;

[0055] Figure 4 This is a schematic diagram of the heterogeneous diamond grinding wheel designed in Scheme 2 of the present invention;

[0056] from Figure 1 It can be seen that the grinding wheel is circular, and the steel core matrix is ​​composed of a circular ring and a raised part on the outside of the circular ring. The raised part has a square wave shape.

[0057] from Figure 2 It can be seen that the grinding wheel is circular, and the steel core matrix consists of a ring and a raised part on the outside of the ring. The raised part is wavy, and the contact interface between the matrix and the working layer is a continuous tangent semicircle in opposite directions.

[0058] from Figure 3 It can be seen that the grinding wheel is circular, and the steel core matrix consists of a ring and a raised part on the outside of the ring. The raised part is serrated. The interface between the steel core matrix and the diamond composite working layer is serrated. The interface between the matrix and the working layer is triangular wave-shaped.

[0059] from Figure 3As can be seen, the grinding wheel is circular. The designed heterogeneous diamond grinding wheel consists of a steel core matrix, a transition layer, and a diamond composite working layer. In the radial direction, the transition layer covers the steel core matrix, and the diamond composite working layer covers the transition layer. In the radial direction, the transition layer is composed of alternating rings of material A (the same material as the matrix) and material B (the same material as the working layer), and the transition layer, the steel core matrix, and the diamond composite working layer are concentric circles. The rings of material A and material B are also concentric circles. The matrix is ​​in contact with the ring of material B, and the outermost ring of material A is in contact with the diamond composite working layer. Between the matrix and the diamond composite working layer, material B and material A layers are alternately arranged in a ring of material B / ring of material A. Detailed Implementation

[0060] This invention relates to a heterogeneous diamond grinding wheel and its preparation method. The technical solution of this invention will be further introduced and explained below with reference to specific embodiments.

[0061] The raw materials involved in this invention are all commercially available powders. The CuSn10 alloy powder has a particle size range of 15–53 μm and good sphericity. The diamond abrasive is 270 / 325 mesh Ti-Cu coated diamond, with a Ti coating thickness of approximately 1–2 μm and a Cu coating thickness of 3–4 μm. The average particle size of the diamond abrasive is 40 μm.

[0062] CuSn10 alloy powder comprises the following components by weight percentage: Cu: 89–91 wt.%, Sn: 9–11 wt.%; Example 1

[0063] Prepare CuSn10 pre-alloyed powder, diamond abrasive, 316L stainless steel matrix powder, and diamond abrasive; mix CuSn10 binder powder with 12.5% ​​diamond abrasive by volume in a three-dimensional slow mixer for 4 hours to obtain diamond composite powder.

[0064] The method for preparing a diamond grinding wheel includes the following steps:

[0065] Step 1:

[0066] The matrix steel material powder (316L stainless steel matrix powder) is placed into the powder feeding cylinder in the forming cavity, and the diamond composite material powder is placed into the powder feeder in the forming cavity. The forming cavity is evacuated to an oxygen content of less than 0.1% and then flowing argon gas is introduced.

[0067] Step Two:

[0068] Import the base model and working layer model files into the SLM device respectively. The inner diameter of the grinding wheel base is 12mm, i.e. Figure 1In this context, r is 12mm, and the outer diameter of the working layer is 80mm, meaning R is 80mm. The interface structure is a square waveform structure (see...). Figure 1 Its square wave amplitude is 5mm.

[0069] Projecting perpendicular to the diameter of the diamond grinding wheel, when the interface between the steel core matrix and the diamond composite working layer has a square waveform, the circumferential proportion of the interface between the steel core matrix and the diamond composite working layer in the square waveform structure region is... It is 50%; where R' is the radius of circle C, l is the distance between two adjacent square waves on circle C, and ∑l is the sum of the distances between adjacent square waves on circle C. Circle C and the grinding wheel base are concentric circles.

[0070] Step 3:

[0071] (1) Spread 316L stainless steel powder on the substrate through a powder spreading roller, extract the substrate model, and laser scan to form a single-layer substrate. The process parameters are laser power 200W and scanning speed 600mm / s.

[0072] (2) Use the built-in micro powder absorber to remove excess steel powder from the substrate;

[0073] (3) The diamond composite material powder is fed to the working layer model by a powder feeder. The mixed powder is spread out by a powder spreading roller and the working layer model is extracted. The single working layer is formed by laser scanning. The process parameters are laser power 120W, scanning speed 700mm / s, and layer thickness 0.05mm.

[0074] (4) Through the above process, the single-layer forming of heterogeneous materials in the same layer is completed. Repeat the above process to complete the multi-layer stacking and forming of a diamond grinding wheel with a thickness of 10mm.

[0075] The average radial stress of the prepared diamond grinding wheel was 25.4 MPa.

[0076] Example 2

[0077] Prepare CuSn10 pre-alloyed powder, diamond abrasive, 316L stainless steel matrix powder, and diamond abrasive; mix CuSn10 binder powder with 12.5% ​​diamond abrasive by volume in a three-dimensional slow mixer for 4 hours to obtain diamond composite powder.

[0078] The method for preparing a diamond grinding wheel includes the following steps:

[0079] Step 1:

[0080] The matrix steel material powder (316L stainless steel matrix powder) is placed into the powder feeding cylinder in the forming cavity, and the diamond composite material powder is placed into the powder feeder in the forming cavity. The forming cavity is evacuated to an oxygen content of less than 0.1% and then flowing argon gas is introduced.

[0081] Step Two:

[0082] Import the base model and working layer model files into the SLM device respectively. The inner diameter of the grinding wheel base is 12mm, i.e. Figure 2 In this context, r is 12mm, and the outer diameter of the working layer is 80mm, meaning R is 80mm. The interface structure is a wavy structure (see...). Figure 2 The interface between the substrate and the working layer is a continuous, tangent, opposite-direction semicircle with an amplitude of 5 mm (r' is 5 mm). The trough of the semicircle, plus half the amplitude, lies on circle C, where the radius of circle C is R' = r + D in mm, where D is 5 mm and r = 12 mm. Projecting perpendicularly to the diameter of the diamond grinding wheel, when the interface between the steel core substrate and the diamond composite working layer is wavy, the circumferential proportion of the interface between the steel core substrate and the diamond composite working layer in the wavy structure area is... It is 50%; where R' is the radius of circle C, l is the distance between two adjacent semicircular waves on circle C, and ∑l is the sum of the distances between adjacent semicircular waves on circle C. Circle C and the grinding wheel base are concentric circles.

[0083] Step 3:

[0084] (1) Spread 316L stainless steel powder on the substrate through a powder spreading roller, extract the substrate model, and laser scan to form a single-layer substrate. The process parameters are laser power 200W and scanning speed 600mm / s.

[0085] (2) Use the built-in micro powder absorber to remove excess steel powder from the substrate;

[0086] (3) The diamond composite material powder is fed to the working layer model by a powder feeder. The mixed powder is spread out by a powder spreading roller and the working layer model is extracted. The single working layer is formed by laser scanning. The process parameters are laser power 120W, scanning speed 700mm / s, and layer thickness 0.05mm.

[0087] (4) Through the above process, the single-layer forming of heterogeneous materials in the same layer is completed. Repeat the above process to complete the multi-layer stacking and forming of a diamond grinding wheel with a thickness of 10mm.

[0088] The average radial stress of the prepared diamond grinding wheel was 31.2 MPa.

[0089] Example 3

[0090] Prepare CuSn10 pre-alloyed powder, diamond abrasive, 316L stainless steel matrix powder, and diamond abrasive; mix CuSn10 binder powder with 12.5% ​​diamond abrasive by volume in a three-dimensional slow mixer for 4 hours to obtain diamond composite powder.

[0091] The method for preparing a diamond grinding wheel includes the following steps:

[0092] Step 1:

[0093] The matrix steel material powder (316L stainless steel matrix powder) is placed into the powder feeding cylinder in the forming cavity, and the diamond composite material powder is placed into the powder feeder in the forming cavity. The forming cavity is evacuated to an oxygen content of less than 0.1% and then flowing argon gas is introduced.

[0094] Step Two:

[0095] Import the base model and working layer model files into the SLM device respectively. The inner diameter of the grinding wheel base is 12mm, i.e. Figure 3 In this context, r is 12mm, and the outer diameter of the working layer is 80mm, meaning R is 80mm. The interface structure is a sawtooth structure (see...). Figure 3 The interface between the substrate and the working layer is a triangular wave (with a apex angle of 7.5°). The amplitude of the triangular wave is 5 mm (i.e., the shortest distance from the apex of the triangular wave to the projection of the circular ring onto the steel core substrate is 5 mm). The trough of the triangular wave with an amplitude of +1 / 2 lies on circle C. The radius of circle C is R' = r + D (in mm), where D is 8 mm and r is 12 mm. Circle C and the grinding wheel substrate are concentric circles. The circumferential proportion of the interface between the steel core substrate and the diamond composite working layer in the serrated structure region is... It is 50%; where l is the distance between two adjacent triangles on circle C, and ∑l is the sum of the distances between adjacent triangles on circle C.

[0096] Step 3:

[0097] (1) Spread 316L stainless steel powder on the substrate through a powder spreading roller, extract the substrate model, and laser scan to form a single-layer substrate. The process parameters are laser power 200W and scanning speed 600mm / s.

[0098] (2) Use the built-in micro powder absorber to remove excess steel powder from the substrate;

[0099] (3) The diamond composite material powder is fed to the working layer model by a powder feeder. The mixed powder is spread out by a powder spreading roller and the working layer model is extracted. The single working layer is formed by laser scanning. The process parameters are laser power 120W, scanning speed 700mm / s, and layer thickness 0.05mm.

[0100] (4) Through the above process, the single-layer forming of heterogeneous materials in the same layer is completed. Repeat the above process to complete the multi-layer stacking and forming of a diamond grinding wheel with a thickness of 10mm.

[0101] The average radial stress of the prepared diamond grinding wheel was 33.4 MPa.

[0102] Example 4

[0103] Prepare CuSn10 pre-alloyed powder, diamond abrasive, 316L stainless steel matrix powder, and diamond abrasive; mix CuSn10 binder powder with 12.5% ​​diamond abrasive by volume in a three-dimensional slow mixer for 4 hours to obtain diamond composite powder.

[0104] The method for preparing a diamond grinding wheel includes the following steps:

[0105] Step 1:

[0106] The matrix steel material powder (316L stainless steel matrix powder) is placed into the powder feeding cylinder in the forming cavity, and the diamond composite material powder is placed into the powder feeder in the forming cavity. The forming cavity is evacuated to an oxygen content of less than 0.1% and then flowing argon gas is introduced.

[0107] Step Two:

[0108] Import the base model and working layer model files into the SLM device respectively. The inner diameter of the grinding wheel base is 12mm, i.e. Figure 4 In this design, r is 12mm, and the outer diameter of the working layer is 80mm, i.e., R is 80mm. The interface structure is a layered structure, wherein the width of a single ring is 1mm, and the number of rings is 4; the 4 rings constitute a transition layer; the first ring, which is in contact with the grinding wheel matrix, is prepared using diamond composite powder as raw material; the second ring, which is in contact with the first and third rings, is prepared using 316L stainless steel matrix powder as raw material; the third ring, which is in contact with the second and fourth rings, is prepared using diamond composite powder as raw material; the fourth ring, which is prepared using 316L stainless steel matrix powder as raw material; and the fourth ring, which is in contact with the outermost diamond composite working layer.

[0109] Step 3:

[0110] (1) Spread 316L stainless steel powder on the substrate through a powder spreading roller, extract the substrate model, and laser scan to form a single-layer substrate. The process parameters are laser power 200W and scanning speed 600mm / s.

[0111] (2) Use the built-in micro powder absorber to remove excess steel powder from the substrate;

[0112] (3) The diamond composite material powder is fed to the working layer model by a powder feeder. The mixed powder is spread out by a powder spreading roller and the working layer model is extracted. The single working layer is formed by laser scanning. The process parameters are laser power 120W, scanning speed 700mm / s, and layer thickness 0.05mm.

[0113] (4) Through the above process, the single-layer forming of heterogeneous materials in the same layer is completed. Repeat the above process to complete the multi-layer stacking and forming of a diamond grinding wheel with a thickness of 10mm.

[0114] 3. The average radial stress of the prepared diamond grinding wheel is 43.6 MPa.

[0115] Comparative Example 1

[0116] The raw materials are exactly the same as those in Examples 1-4; the difference is:

[0117] The method for preparing a diamond grinding wheel includes the following steps:

[0118] Step 1:

[0119] The matrix steel material powder (316L stainless steel matrix powder) is placed into the powder feeding cylinder in the forming cavity, and the diamond composite material powder is placed into the powder feeder in the forming cavity. The forming cavity is evacuated to an oxygen content of less than 0.1% and then flowing argon gas is introduced.

[0120] Step Two:

[0121] (2) Import the base model and working layer model files into the SLM device respectively. The inner diameter of the grinding wheel base is 12mm, and the outer diameter of the working layer is 80mm. The interface structure is a conventional structure, that is, the base and the working layer are concentric circles, that is, there is no transition layer in the radial direction, the grinding wheel base directly contacts the working layer in a circular shape, and the shape formed by the contact interface between the base and the working layer is circular.

[0122] Step 3:

[0123] (1) Spread 316L stainless steel powder on the substrate through a powder spreading roller, extract the substrate model, and laser scan to form a single-layer substrate. The process parameters are laser power 200W and scanning speed 600mm / s.

[0124] (2) Use the built-in micro powder absorber to remove excess steel powder from the substrate;

[0125] (3) The CuSn10-diamond mixed powder is fed to the working layer model by a powder feeder. The mixed powder is spread out by a powder spreading roller and then the working layer model is extracted. The single working layer is formed by laser scanning. The process parameters are laser power 120W, scanning speed 700mm / s, and layer thickness 0.05mm.

[0126] (4) Through the above process, the single-layer forming of heterogeneous materials in the same layer is completed. Repeat the above process to complete the multi-layer stacking and forming of a diamond grinding wheel with a thickness of 10mm.

[0127] The average radial stress of the prepared diamond grinding wheel was 97.2 MPa.

Claims

1. A heterogeneous diamond grinding wheel, characterized in that: The heterogeneous diamond grinding wheel comprises a steel core matrix, a transition layer, and a diamond composite working layer. The steel core matrix, transition layer, and diamond composite working layer are formed using a 3D printing process. In the radial direction, the transition layer covers the steel core matrix, and the diamond composite working layer covers the transition layer. In the radial direction, the transition layer consists of alternating rings of material A and material B, and the transition layer, the steel core matrix, and the diamond composite working layer are concentric circles. The rings of material A and material B are also concentric circles. The material of material A is the same as that of the steel core matrix, and the material of material B is the same as that of the diamond composite working layer. The matrix is ​​in contact with the ring of material B, and the outermost ring of material A is in contact with the diamond composite working layer. Between the matrix and the diamond composite working layer, material B and material A layers are alternately arranged in a ring of material B / ring of material A. Projecting perpendicular to the diameter of the diamond grinding wheel, the projection of the diamond grinding wheel is a ring with radius R, where R is 60-100mm; the projection of the steel core matrix is ​​a ring with radius r, where r is 15-25mm; the projection of a ring of material B is a ring with a ring width of 1-8mm; the projection of a ring of material A is a ring with a ring width of 1-5mm.

2. The heterogeneous diamond grinding wheel of claim 1, wherein: The diamond composite working layer is composed of a binder and diamond micro powder. The binder includes the following components by mass percentage: Cu: 89~91wt.%, Sn: 9~11wt.%; the volume percentage of diamond added in the diamond composite working layer is 12.5%-25%.

3. The heterogeneous diamond grinding wheel of claim 1, wherein: The average particle size of diamond micron powder is 40μm-90μm; The steel core matrix is ​​made of one of the tough structural steels that can be laser-formed, such as 316L stainless steel, 304 stainless steel, and 17-4 PH stainless steel.

4. The heterogeneous diamond grinding wheel according to claim 1, characterized in that: Projecting perpendicular to the diameter of the diamond grinding wheel, the projection of the diamond grinding wheel is a circular ring with a radius of R, where R is 78-82 mm; the projection of the steel core matrix is ​​a circular ring with a radius of r, where r is 18-22 mm.

5. A heterogeneous diamond grinding wheel according to claim 1, characterized in that: The interface between the substrate and the working layer consists of concentric rings of two materials, each ring being 1-2 mm wide. There are 2N concentric rings, where N is any integer between 1 and 20.

6. A heterogeneous diamond grinding wheel according to claim 5, characterized in that: The value of N is any integer between 2 and 5.

7. A method for preparing a heterogeneous diamond grinding wheel as described in any one of claims 1-5; comprising the following steps: Step 1: The steel material powder for the matrix is ​​placed into the powder feeding cylinder in the forming cavity, and the diamond composite material powder is placed into the powder feeder in the forming cavity. The forming cavity is evacuated until the oxygen content is less than 0.1%, and then flowing argon gas is introduced. Step Two: Draw the matrix model, working layer model, and transition layer model of the heterogeneous diamond grinding wheel, and import the matrix model file, working layer model file, and transition layer model file into the SLM device respectively; Step 3: Laser scanning is performed on the imported matrix model file, working layer model file, and transition layer model file from the SLM device to form a heterogeneous diamond grinding wheel.

8. The method for preparing a heterogeneous diamond grinding wheel according to claim 7, characterized in that: When forming the steel core substrate, the laser power is controlled at 200-400W and the scanning speed is 600-1200mm / s; When forming the working layer of diamond composite material, the laser power is controlled at 120-180W, the scanning speed is 700-1100mm / s, and the layer thickness is 0.05mm-0.09mm.

9. The method for preparing a heterogeneous diamond grinding wheel according to claim 7, characterized in that: When printing the transition layer designed in Scheme 2, when printing material layer A, the laser power is controlled at 200-400W and the scanning speed is 600-1200mm / s; when printing material layer B, the laser power is controlled at 120-180W, the scanning speed is 700-1100mm / s, and the layer thickness is 0.05mm-0.09mm. The average radial stress of the obtained heterogeneous diamond grinding wheels ranged from 25.4 MPa to 43.6 MPa.

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