CN113561074B - Preparation method and device of diamond grinding head and base material thereof - Google Patents
Preparation method and device of diamond grinding head and base material thereof Download PDFInfo
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- CN113561074B CN113561074B CN202110865645.1A CN202110865645A CN113561074B CN 113561074 B CN113561074 B CN 113561074B CN 202110865645 A CN202110865645 A CN 202110865645A CN 113561074 B CN113561074 B CN 113561074B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
- B24D3/06—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements
- B24D3/10—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements for porous or cellular structure, e.g. for use with diamonds as abrasives
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
- B24D18/0009—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for using moulds or presses
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
- B24D18/0054—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for by impressing abrasive powder in a matrix
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
- B24D7/02—Wheels in one piece
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
- B24D7/16—Bushings; Mountings
Abstract
The invention particularly relates to a preparation method and a device of a diamond grinding head and a base material thereof, belonging to the technical field of preparation of diamond grinding tools, wherein the method comprises the following steps: mixing the metal bonding agent and the diamond abrasive particles to obtain a mixture; cold press molding the mixture to obtain a blank; obtaining a base material, wherein the base material comprises a blade part, and the blade part comprises a casting head end and a casting tail end; placing the blank at the head end of the casting of the base material, and then heating the blank to make the molten blank cast towards the tail end of the casting along the head end of the casting so as to obtain the base material covered with the molten layer; sintering the base material covered with the melting layer to obtain a primary product; shaping and edging the primary product to obtain a diamond grinding head; after the blank is heated and melted, certain flow is generated to cover and wrap the base material to form an abrasive grain layer with a required shape; solves the problems of complex forming process and sintering cracking after forming when manufacturing the grinding head with a more complex shape and a larger length-diameter ratio.
Description
Technical Field
The invention belongs to the technical field of preparation of diamond grinding tools, and particularly relates to a preparation method and a preparation device of a diamond grinding head and a base material of the diamond grinding head.
Background
The metal bond sintering grinding head is widely applied to processing of brittle and hard materials such as ceramics, sapphires, glass and the like due to the excellent service life of the metal bond sintering grinding head. The manufacturing process generally comprises molding, sintering and modifying. The molding and sintering process is the most important step in the manufacturing process of the sintering grinding head. The shape and size of the grinding head determine whether the molding process is complex or not, and the sintering process determines the performance of the grinding head.
The prior grinding head is prepared by molding a grinding head blank through cold pressing, and the shape of the blank determines the design of a molding process. And placing the mixture into a die, and then performing unidirectional or bidirectional jacking by using a stamping die. The mixture is prepared into a state suitable for pressure forming in advance, and a forming blank with certain strength is formed after jacking. After the molding is finished, the blank and the base material should keep good contact, and then the blank is sent into a vacuum sintering furnace for pressureless sintering.
However, for some molded blanks with complicated shapes or larger long diameters, the molding process has certain limitations. The complicated shape is difficult to be formed, or only a large blank with a large trimming allowance can be formed, which causes the consumption of the subsequent process and the increase of the cost. For the shape with larger length-diameter ratio, the cold press molding is difficult to ensure the uniformity of the internal pressure distribution of the blank, and the blank is easy to crack in the sintering process to cause waste products.
Disclosure of Invention
The application aims to provide a preparation method and a device of a diamond grinding head and a base material thereof, so as to solve the problems that the existing complex shape is difficult to form and the sintering cracking of the shape with larger length-diameter ratio is difficult to realize.
The embodiment of the invention provides a preparation method of a diamond grinding head, which comprises the following steps:
mixing the metal bonding agent and the diamond abrasive particles to obtain a mixture;
cold press molding the mixture to obtain a blank;
obtaining a base material, wherein the base material comprises a blade part, and the blade part comprises a casting head end and a casting tail end;
placing the blank at the head end of the casting of the base material, and then heating the blank to make the molten blank cast towards the tail end of the casting along the head end of the casting so as to obtain the base material covered with the molten layer; the heating temperature T1 and the preform melting point temperature T2 satisfy the following relationship: t1 is more than or equal to T2+50 ℃;
sintering the base material covered with the melting layer to obtain a primary product;
and (4) shaping and edging the primary product to obtain the diamond grinding head.
Optionally, the green body is placed at the head end of the base material for casting, and then heated, so that the molten green body is cast from the head end to the tail end of the base material for casting to obtain the base material covered with the molten layer,
the casting head temperature T3 and the green melt temperature T2 satisfy the following relationship: t2+50 ℃ and T3 ≤
T2+100℃；
The casting end temperature T4 and the green body melting point temperature T2 satisfy the following relationship: t2+100 ℃ and T4 ≤
T2+150℃；
The casting end temperature T4 is higher than the casting head temperature T3.
Optionally, the temperature T4 of the casting end and the temperature T3 of the casting head end satisfy the following relationship: T4-T3 < 50 ℃.
Optionally, the particle size of the metal bond is not greater than 300 meshes, the particle size of the diamond abrasive particles is 150 meshes to 600 meshes, and the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 4-10.
Optionally, when the granularity of the diamond abrasive particles is larger than or equal to 150 meshes and smaller than 250 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 4-6;
when the granularity of the diamond abrasive particles is larger than or equal to 250 meshes and smaller than 400 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 6-8;
when the granularity of the diamond abrasive particles with the granularity of 400 meshes or less is less than 600 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 8-10.
Optionally, the blank further comprises superfine micro powder for adjusting the fluidity of the metal binder, the granularity of the superfine micro powder is not less than 1000 meshes, the superfine micro powder comprises at least one of ceramic balls, silicon carbide, titanium carbide, tungsten powder and iron powder, and the weight of the superfine micro powder is not more than 5% of that of the mixture.
Optionally, the preform has a columnar structure, a central axis of the preform coincides with a central axis of the base material, and an aspect ratio of the preform is 1: 1-2: 1.
optionally, the blank is provided with a positioning groove for positioning and butting the blank and the base material.
Based on the same inventive concept, the embodiment of the invention also provides a preparation device of the diamond grinding head, which comprises:
the shell is internally provided with a cavity;
the partition plate is arranged in the shell and used for dividing the cavity into a low-temperature area and a high-temperature area, the low-temperature area is used for heating the blank and the casting head end of the base material, and the high-temperature area is used for heating the casting tail end of the base material;
and the heating unit is arranged in the cavity and used for adjusting the temperature of the high-temperature area and the low-temperature area.
Based on the same inventive concept, the embodiment of the invention also provides a base material of the diamond grinding head, the base material comprises a handle part and a blade part which are connected with each other, the blade part comprises a casting head end and a casting tail end, and the casting tail end is provided with a flow stopping area for limiting the flow of the stock melt.
Optionally, the blade part is provided with a flow groove along the direction of the stock melt.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
the preparation method of the diamond grinding head provided by the embodiment of the invention comprises the following steps: mixing the metal bonding agent and the diamond abrasive particles to obtain a mixture; cold press molding the mixture to obtain a blank; obtaining a base material, wherein the base material comprises a blade part, and the blade part comprises a casting head end and a casting tail end; placing the blank at the head end of the casting of the base material, and then heating the blank to make the molten blank cast towards the tail end of the casting along the head end of the casting so as to obtain the base material covered with the molten layer; the heating temperature T1 and the preform melting point temperature T2 satisfy the following relationship: t1 is more than or equal to T2+50 ℃; sintering the base material covered with the melting layer to obtain a primary product; shaping and edging the primary product to obtain a diamond grinding head; after the blank is heated and melted, certain flow is generated to cover and wrap the base material to form an abrasive grain layer with a required shape; solves the problems of complex forming process and sintering cracking after forming when manufacturing the grinding head with a more complex shape and a larger length-diameter ratio.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a flow chart of a method provided by an embodiment of the present invention;
FIG. 2 is a schematic diagram of a preparation process provided in example 1 of the present invention;
FIG. 3 is a schematic diagram of a preparation process provided in example 2 of the present invention;
FIG. 4 is a schematic diagram of the preparation process provided in comparative example 2 of the present invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
the applicant finds in the course of the invention that: the mixture of the metal bonding agent and the diamond abrasive particles has certain fluidity on a liquid phase line, so that the molding blank is placed at a high position of the base material, and the blade part of the base material is uncovered by the blank; on the base material of the blade part, the temperature difference is constructed, the temperature of the place where the blank is placed is lower, the temperature of the tail end of the base material blade part is higher, the temperature of the two places are both higher than the liquidus line of the metal binding agent, and the temperature difference is not more than 50 degrees. The molding material blank is heated and melted, the temperature of the position where the molding material blank is located is relatively low, the molding material blank can flow towards the position with higher temperature (the tail end of the base material of the blade part) after being melted, and the wrapping and covering of the base material of the blade part are completed in the flow casting process. And after the sintering is finished and the temperature is reduced, the blank is changed into a solid phase again to form a complete sintered blank of the grinding working layer.
According to an exemplary embodiment of the present invention, there is provided a method of manufacturing a diamond grinding head, the method including:
s1, mixing a metal bonding agent and diamond abrasive particles to obtain a mixture;
as an alternative embodiment, the particle size of the metal bond is not larger than 300 meshes, the particle size of the diamond abrasive particles is 150 to 600 meshes, and the mixing mass ratio of the diamond abrasive particles and the metal bond is 1: 4-10.
Specifically, the metal binder may be selected from common metal binders such as copper-based, silver-copper-based, and copper-tin-based, and the shape of the metal binder is spherical.
More optimally, in order to ensure that the mixture has good fluidity above the liquidus line of the metal bond, the applicant finds that the proportion of the diamond abrasive particles and the metal bond can be adjusted according to the granularity of the diamond abrasive particles, so as to further realize the control of the fluidity, and the method specifically comprises the following steps:
when the granularity of the diamond abrasive particles is larger than or equal to 150 meshes and smaller than 250 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 4-6;
when the granularity of the diamond abrasive particles is larger than or equal to 250 meshes and smaller than 400 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 6-8;
when the granularity of the diamond abrasive particles with the granularity of 400 meshes or less is less than 600 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 8-10.
As an optional implementation mode, the fluidity of the metal bonding agent can be further adjusted by adding ultrafine powder with the particle size of more than 1000 meshes, and the ultrafine powder can be selected from ceramic balls, silicon carbide, titanium carbide, tungsten powder, iron powder and the like; the addition of the superfine powder is generally not more than 5 percent of the weight of the existing mixture.
S2, carrying out cold press molding on the mixture to obtain a blank;
the mass of the blank can be obtained by calculation, specifically, the material layer volume required by the finished product is calculated according to the finished product size design of the grinding head, the material layer mass of the finished product can be obtained by multiplying the material layer volume by the density, about 30 percent of material layers are removed by considering the discharge modification after sintering, the normal loss of the tape casting sintering is considered, the mass of the blank is designed to be 150 percent of the material layer mass of the finished product, and in sum, the aim of covering all blade parts of the base material according to the designed thickness is achieved.
The cold press molding adopts a common cold press molding process, and specifically comprises the following steps: the prealloying powder, diamond abrasive particles and other additive components are wetted and scattered by alcohol, and stirred in a stirrer for 4 hours; mixing uniformly, processing, applying pressure by a press machine by using a corresponding die and a punch, and cold-pressing and molding into a blank with certain strength.
As an alternative embodiment, the preform has a columnar structure, the central axis of the preform and the central axis of the base material coincide, and the preform has an aspect ratio of 1: 1-2: 1.
the length-diameter ratio is not more than 2:1, and the existing cold press molding mostly adopts the value, so the value is very friendly and convenient to the molding process, and the shape is more easy to melt and flow when the subsequent sintering and melting are delayed.
In order to facilitate accurate butt joint of the blanks and the base materials, the blanks are provided with positioning grooves which are used for realizing the positioning butt joint of the blanks and the base materials. Specifically, the shape of the positioning groove of the preform changes according to the shape of the base material, for example, when the base material is cylindrical, the positioning groove of the preform is a circular blind hole, and when the base material is umbrella-shaped, the positioning groove of the preform is a corresponding spherical groove.
S3, obtaining a base material, wherein the base material comprises a blade part, and the blade part comprises a casting head end and a casting tail end;
s4, placing the blank at the head end of the casting of the base material, and then heating the blank to make the molten blank cast towards the tail end of the casting along the head end of the casting so as to obtain the base material covered with the molten layer; the heating temperature T1 and the preform melting point temperature T2 satisfy the following relationship: t1 is more than or equal to T2+50 ℃;
the applicant finds in the course of the invention that: if the heating temperature T1 is not higher than T1 and more than T2+50 ℃, the melting degree of the sintered body is reduced, the tape casting is difficult to occur, the energy supply for the chemical bonding reaction between the diamond and the metal bonding agent is insufficient under the condition of low temperature, the reaction is insufficient, the performance of the finished product is poor, and the heating temperature T1 cannot be too high, generally, T1 is less than T2+100 ℃.
In an alternative embodiment, the green body is placed at the casting head end of the base material and then heated so that the molten green body is cast from the casting head end to the casting end to obtain a base material covered with a molten layer,
the casting head temperature T3 and the green melt temperature T2 satisfy the following relationship: t3 is more than or equal to T3578 and more than or equal to T2 and 100 ℃ at the temperature of T2 and 50 ℃;
the casting end temperature T4 and the green body melting point temperature T2 satisfy the following relationship: t4 is more than or equal to T3578 and more than or equal to T2 and 150 ℃ at the temperature of T2 and 100 ℃;
the casting end temperature T4 and the casting head temperature T3 satisfy the following relationship: T4-T3 is more than 0 ℃ and less than 50 ℃.
The temperature of the casting tail end is controlled to be 100-150 ℃ higher than the liquid phase point of the used metal bonding agent, the temperature value is too high, the casting is violent, the control is not easy, products are easy to scrap, and the diamond is easy to carbonize at the too high temperature, so that the too high temperature is avoided as far as possible; if the temperature value is too low, the temperature difference between the sintered body and a low-temperature area cannot be opened, the temperature difference is small, and the casting driving force of the sintered body is not strong.
The temperature of the head end of the casting is controlled to be 50-100 ℃ higher than the liquid phase point of the used metal binding agent, if the temperature value is too high, the temperature difference with a high-temperature area cannot be opened, the temperature difference is small, and the casting driving type of a sintered body is not strong; the temperature value is too low, the melting degree of the sintered body is reduced, the tape casting is difficult to occur, and under the condition of low temperature, the energy supply for the chemical bonding reaction of the diamond and the metal bonding agent is insufficient, the reaction is insufficient, and the performance of the finished product is poor.
The temperature T4 at the end of the casting was higher than the temperature T3 at the head end of the casting.
The applicant finds that the blank is melted and cast by gravity alone, but the melting effect is limited, the blank can be self-balanced only along a very short casting distance of the base material and is not cast any more, and the casting direction is random and uncontrollable, so that the defective rate is high; and the temperature T4 that adopts the curtain coating end is higher than the temperature T3 of curtain coating head end, under the environment of artificial creation difference in temperature, the stock will produce very strong curtain coating trend along the difference in temperature direction, can realize better, controllable curtain coating, accomplish the cladding of whole blade, more optimized, the temperature difference of the temperature T4 of curtain coating end and the temperature T3 of curtain coating head end does not generally exceed 50 ℃, exceeds 50 ℃ and can cause the curtain coating state too violent, difficult control, the yield is low.
S5, sintering the base material covered with the melting layer to obtain an initial product;
the sintering can adopt a common sintering process, for example, vacuumizing to a corresponding vacuum value, starting heating, generally heating to about 600 ℃, entering heat preservation time, beginning to decompose and volatilize impurities due to the excessive solvent in the blank at the moment, preserving heat for about 1 hour, then heating to the maximum specified temperature, preserving heat for about 1 hour, then closing the heating, naturally cooling, and finishing sintering.
In the sintering process, a solid phase of a blank positioned at the top end of the base material is converted into a liquid phase along with the temperature rise, the blank flows along the base material at the blade part, and the liquid blank has very strong driving force to flow towards a high-temperature area of the base material due to the temperature difference; and after sintering, cooling, solidifying the liquid blank, and finishing covering and wrapping the blade part of the base material.
And S6, shaping and edging the primary product, and processing the grinding head blank to a finished product size to obtain the diamond grinding head.
According to another exemplary embodiment of the present invention, there is also provided a diamond grinding head manufacturing apparatus, including:
the shell is internally provided with a cavity;
the partition plate is arranged in the shell and used for dividing the cavity into a low-temperature area and a high-temperature area, the low-temperature area is used for heating the blank and the casting head end of the base material, and the high-temperature area is used for heating the casting tail end of the base material;
and the heating unit is arranged in the cavity and used for adjusting the temperature of the high-temperature area and the low-temperature area.
According to the heating principle of difference, through infrared ray light screen or thermal-insulated tile, can build the difference in temperature, place the high temperature region in with the substrate stalk portion, place the low temperature region in with the substrate blade portion, design abrasive particle layer cover substrate regional end (be the curtain coating end), locate the boundary position in high temperature and low temperature region.
According to another exemplary embodiment of the invention, a base material of a diamond grinding head is further provided, the base material comprises a handle part and a blade part which are connected with each other, the blade part comprises a casting head end and a casting tail end, and the casting tail end is provided with a flow stopping area for limiting the flow of stock melt; specifically, when the base material is cylindrical, a flow stopping groove can be arranged at the tail end of the casting to realize the flow stopping of the stock melt; when the base material structure is umbrella-shaped, the blade part and the handle part have abrupt change parts and naturally have a flow stopping area, so that the structure is similar to the structure, and the flow stopping area does not need to be added manually.
As an alternative embodiment, the substrate may be designed with structures that enhance the cast wetting, such as cones, frustums, etc., and runner channel designs may be added as necessary.
The method and apparatus for manufacturing the diamond wheel head of the present application and the substrate thereof will be described in detail with reference to examples, comparative examples and experimental data.
Example 1
A method for preparing a diamond grinding head comprises the following steps:
bronze-based binders, copper 70%, silver 20%, tin 8%, others 2% were used. The liquidus is 870 ℃;
the diamond is MBD10 type 400 mesh diamond; the mass ratio of the diamond to the bonding agent is 1: 7.5;
the base material structure comprises a handle part and a blade part, as shown in figure 2, the diameter of the handle part is 6mm, the diameter of the blade part is 5mm, the length of the blade part is 30mm, and the length of the handle part is 60 mm;
the blank is formed by one-way cold pressing, the diameter of the blank is 10mm, the height of the blank is 8mm, a matching hole is arranged at the bottom of the blank and can be matched with the top end of the blade part of the base material, the depth of the matching hole is 1mm, and the matching gap is 0.05-0.1 mm;
the sintering adopts infrared heating and vacuum pumping to 10-3Pa, and is equipped with the light screen to insulate against heat, the substrate stalk is located the light screen inboard, receives the radiation heat transfer of the infrared lamp, the substrate blade is located the light screen outside, has isolated the radiation of the infrared lamp of lower part, can only accept the radiation heating of the infrared lamp of outside. The number and power of the infrared lamp tubes on the inner side and the outer side of the shading plate are different, the heating effect is detected by thermocouples distributed in the heating area, and the heating is controlled by a computer. The inside temperature is set at 1100 deg.C and the outside temperature at 1000 deg.C, and the temperature difference between the base material and the preform itself is actually less than 100 deg.C because of the heat conduction between the base material and the preform itself.
When the sintering reaches the highest temperature and the temperature is kept, the sintering blank (blank) begins to slowly melt and gradually collapses and moves downwards to wrap the end part of the base material, and the heat conduction temperature of the base material is higher and higher along with the gradual liquefaction and the downward movement of the sintering blank, so that the phenomenon of accelerated downward movement is generated. After the high temperature heat preservation for 25min, the liquid sintering blank covers the complete blade part base material and sinks into the flow stopping groove at the tail end of the blade part. And adjusting the power of the infrared lamp tube in the high-temperature region to be consistent with that in the low-temperature region, starting cooling the high-temperature region, and continuing to preserve heat after the temperature in the low-temperature region is reached. At this time, the sintering process enters a common copper-based and bronze-based high-temperature heat-preservation sintering stage, and the process is not repeated. And after sintering is completely finished, closing heating and filling argon to rapidly cool, and ensuring that the cooling rate in a temperature range above the solidus of the sintered blank is controlled to be above 50 ℃/min so as to prevent the sintered blank from further liquefying and flowing.
After sintering, the diameter of the blade part is irregular, the diameter of the minimum part is 7.4mm, and the allowance of 0.4mm is provided according to the requirement of the diameter of 7mm of the finished product; and (4) trimming the size of the grinding head in place through electric spark trimming.
Example 2
A method for preparing a diamond grinding head comprises the following steps:
bronze-based binders, 60% copper, 25% silver, 13% tin, and 2% others were used. Liquidus of 840 °; the diamond is MBD10 type 180 mesh diamond; the mass ratio of the diamond to the bonding agent is 1: 6;
the base material structure comprises a handle part and a blade part, and as shown in figure 3, the diameter of the umbrella-shaped blade part of the base material is 30 mm;
the sintering adopts infrared heating and vacuum pumping to 10-3Pa, and a shading plate is arranged for heat insulation, the position of the material blank is separated from the outer edge of the base material blade part, the position of the material blank is heated by fewer infrared lamp tubes, and the outer edge area of the base material blade part is heated by more infrared lamp tubes. The infrared lamp tubes on the two sides of the shading plate have different numbers and powers, the heating effect is detected by thermocouples distributed in the heating area, and the heating is controlled by a computer. The temperature in the low temperature region is set to 1000 ℃ and the temperature in the high temperature region is set to 900 ℃, and the temperature difference between the base material and the preform is actually less than 100 ℃ because the base material and the preform can conduct heat.
When the sintering reaches the highest temperature and is kept warm, the sintering blank (blank) starts to melt slowly and gradually melts and flows, the curved surface of the edge part of the base material is covered and wrapped, the sintering blank is gradually liquefied and flows, the heat conduction temperature of the base material is higher and higher, and the phenomenon of accelerated flow occurs. After the high temperature heat preservation for 20min, the liquid state sintering blank covers the complete blade part base material. And adjusting the power of the infrared lamp tube in the high-temperature region to be consistent with that in the low-temperature region, starting cooling the high-temperature region, and continuing to preserve heat after the temperature in the low-temperature region is reached. At this time, the sintering process enters a common copper-based and bronze-based high-temperature heat-preservation sintering stage, and the process is not repeated. And after sintering is completely finished, closing heating and filling argon to rapidly cool, and ensuring that the cooling rate in a temperature range above the solidus of the sintered blank is controlled to be above 50 ℃/min so as to prevent the sintered blank from further liquefying and flowing.
After sintering, the diameter of the blade part is irregular by measurement, the thinnest part of the circular arc surface of the blade part of the base material covered with the sand layer reaches 1.8mm and exceeds 1.5mm of the designed thickness, and the sand layer at the blade part is trimmed into a smooth arc surface by electric spark trimming, so that a finished product is obtained.
Comparative example 1
The process of this comparative example is the same as that used in example 1, except that:
the mass ratio of diamond and the bonding agent is 1:10, the inner side temperature of the shading plate is 1150 ℃, the outer side temperature is 950 ℃, and the temperature difference between the base material and the blank is actually less than 200 ℃ but more than 100 ℃ because the base material and the blank can conduct heat.
The blank flows violently due to the change of the proportion and the temperature difference, and after cooling and solidification, the shape and the size cannot be ensured, thereby causing waste products.
Comparative example 2
The same grinding head as in example 2 was prepared for this comparative example, and the process was as follows:
it is first necessary to form a larger preform with the base material by cold pressing, as shown in fig. 4, and then sinter the preform.
Because the diameter of the blank is large, cracking easily occurs in the forming process, the density is uneven, and the forming difficulty is large.
In the sintering process, because of uneven density of the blanks, the transformation and shrinkage ratios of sintering solid-liquid phases are different, cracks can be generated, in addition, bulges and air holes are generated when some components with low melting points in the blanks are liquefied under high temperature, and the blanks can only be discharged from the outer surface of the blanks due to the large attaching area of the blanks and the base materials, so that the holes and the bulges are generated, and the products are scrapped.
20 random tests were carried out on the products obtained in examples 1-2 and comparative examples 1-2, and the results are shown in the following table.
From the above table, the grinding head prepared by the same method of the embodiment of the invention has less defects and high yield, and solves the problems of complex forming process and sintering cracking after forming when manufacturing the grinding head with a complicated shape and a larger length-diameter ratio.
One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:
(1) the method provided by the embodiment of the invention utilizes the fact that the mixture of the metal bond and the diamond abrasive particles has certain fluidity on a liquid phase line; placing the molding blank at a high position of the base material, wherein the blade part of the base material is uncovered by the blank and exposed; on the base material of the blade part, the temperature difference is constructed, the temperature of the place where the blank is placed is lower, the temperature of the tail end of the base material blade part is higher, the temperature of the two places are both higher than the liquidus line of the metal binding agent, and the temperature difference is not more than 50 degrees. The molding material blank is heated and melted, the temperature of the position where the molding material blank is located is relatively low, the molding material blank can flow towards the position with higher temperature (the tail end of the base material of the blade part) after being melted, and the wrapping and covering of the base material of the blade part are completed in the flow casting process. And after the sintering is finished and the temperature is reduced, the blank is changed into a solid phase again to form a complete sintered blank of the grinding working layer.
(2) The method provided by the embodiment of the invention adopts a temperature difference forming sintering process, combines the forming and sintering processes into a procedure by utilizing the characteristic that the metal bonding agent can flow towards a higher-temperature area when being converted into a liquid phase, and ensures that a blank generates certain flow after being heated and melted by controlling the temperature difference to cover and wrap a base material to form an abrasive grain layer with a required shape.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method for preparing a diamond grinding head is characterized by comprising the following steps:
mixing the metal bonding agent and the diamond abrasive particles to obtain a mixture;
cold press molding the mixture to obtain a blank;
obtaining a base material, wherein the base material comprises a blade part, and the blade part comprises a casting head end and a casting tail end;
placing the blank at the head end of the casting of the base material, and then heating the blank to make the molten blank cast towards the tail end of the casting along the head end of the casting so as to obtain the base material covered with the molten layer; the heating temperature T1 and the preform melting point temperature T2 satisfy the following relationship: t1 is more than or equal to T2+50 ℃;
sintering the base material covered with the melting layer to obtain a primary product;
and (4) shaping and edging the primary product to obtain the diamond grinding head.
2. The method for manufacturing a diamond wheel head according to claim 1, wherein the green compact is placed at a casting head end of the base material and then heated so that the molten green compact is cast from the casting head end to the casting end to obtain a molten layer-covered base material,
the casting head temperature T3 and the green melt temperature T2 satisfy the following relationship: t3 is more than or equal to T3578 and more than or equal to T2 and 100 ℃ at the temperature of T2 and 50 ℃;
the casting end temperature T4 and the green body melting point temperature T2 satisfy the following relationship: t4 is more than or equal to T3578 and more than or equal to T2 and 150 ℃ at the temperature of T2 and 100 ℃;
the casting end temperature T4 is higher than the casting head temperature T3.
3. The method of making a diamond grinding head according to claim 2, wherein the temperature T4 of the casting tip and the temperature T3 of the casting head satisfy the following relationship: T4-T3 < 50 ℃.
4. The method for manufacturing a diamond grinding head according to claim 1, wherein the grain size of the metal bond is not larger than 300 mesh, the grain size of the diamond abrasive grains is 150 mesh to 600 mesh, and the mixing mass ratio of the diamond abrasive grains to the metal bond is 1: 4-10.
5. The method for manufacturing a diamond grinding head according to claim 4, wherein when the grain size of the diamond abrasive grains is 150 mesh or less and is less than 250 mesh, the mixing mass ratio of the diamond abrasive grains and the metal bond is 1: 4-6;
when the granularity of the diamond abrasive particles is larger than or equal to 250 meshes and smaller than 400 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 6-8;
when the granularity of the diamond abrasive particles with the granularity of 400 meshes or less is less than 600 meshes, the mixing mass ratio of the diamond abrasive particles to the metal bond is 1: 8-10.
6. The method for manufacturing a diamond grinding head according to claim 1, wherein the material blank further comprises ultra-fine powder for adjusting the fluidity of the metal bond, the particle size of the ultra-fine powder is not less than 1000 meshes, the ultra-fine powder comprises at least one of ceramic balls, silicon carbide, titanium carbide, tungsten powder and iron powder, and the weight of the ultra-fine powder is not more than 5% of the weight of the mixture.
7. The method for manufacturing a diamond grinding head according to claim 1, wherein the green compact has a columnar structure, the central axis of the green compact coincides with the central axis of the base material, and the aspect ratio of the green compact is 1: 1-2: 1; the material blank is provided with a positioning groove, and the positioning groove is used for realizing the positioning butt joint of the material blank and the base material.
8. A diamond grinding head manufacturing device is characterized by comprising:
the shell is internally provided with a cavity;
the partition plate is arranged in the shell and used for dividing the cavity into a low-temperature area and a high-temperature area, the low-temperature area is used for heating the preform and the head end of the preform melt flow casting of the base material, and the high-temperature area is used for heating the tail end of the preform melt flow casting of the base material;
and the heating unit is arranged in the cavity and used for adjusting the temperature of the high-temperature area and the low-temperature area.
9. The base material of the diamond grinding head is characterized by comprising a handle part and a blade part which are connected with each other, wherein the blade part comprises a head end of stock melt flow casting and a tail end of the stock melt flow casting, and the tail end of the stock melt flow casting is provided with a flow stopping area for limiting the flow of the stock melt.
10. The base material for a diamond grinding head according to claim 9, wherein the blade portion is provided with a flow groove along a casting direction of the stock melt.
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| JPS63200968A (en) * | 1987-02-12 | 1988-08-19 | Sintokogio Ltd | Manufacture for super-abrasive grain grindstone |
| CN101934501B (en) * | 2010-08-26 | 2012-07-25 | 郑州磨料磨具磨削研究所 | Self-propagating sintering metal-bonded diamond grinding wheel and preparation method thereof |
| CN104842286A (en) * | 2015-05-20 | 2015-08-19 | 广东工业大学 | Superhard grinding tool and manufacturing method thereof |
| CN106378715B (en) * | 2016-10-10 | 2019-10-29 | 江苏韦尔博新材料科技有限公司 | A kind of manufacturing method of self- propagating diamond Engraving grinding head |
| CN107520766B (en) * | 2017-09-28 | 2019-04-30 | 东北大学 | A kind of method of laser melting and coating process production metallic bond super hard abrasive structuring arrangement cross grinding grinding wheel |
| CN109227412B (en) * | 2018-09-07 | 2020-08-07 | 杨凌美畅新材料股份有限公司 | Preparation method of fan-shaped diamond tool bit |
| CN109352540A (en) * | 2018-12-13 | 2019-02-19 | 东北大学 | A kind of macro-structured peripheral grinding grinding wheel of coaxial powder-feeding laser melting coating metallic bond super-hard abrasive and preparation method thereof |
| CN110078511B (en) * | 2019-03-11 | 2021-10-12 | 昆明理工大学 | Ti3AlC2Method for preparing diamond drilling tool bit based on ceramic bond |
| CN111993297B (en) * | 2020-08-13 | 2022-02-01 | 武汉理工大学 | Preparation method of ceramic-metal composite diamond dresser |
| CN112008619B (en) * | 2020-09-03 | 2021-07-27 | 湖南科技大学 | Preparation method of ordered diamond brazing grinding wheel with porous structure |
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