CN109551383B - Combination electroplating CBN grinding wheel for camshaft grinding and manufacturing method thereof - Google Patents

Abstract

A combined electroplating CBN grinding wheel for camshaft grinding and a manufacturing method thereof belong to the technical field of design and manufacture of abrasives. Combination electroplating CBN grinding wheel for grinding different parts, the side of the camshaft away from the combined electroplating CBN grinding wheel is topped with a guide wheel. Grinding wheel and a number of grinding wheels for grinding external cylindrical journals, wherein the grinding wheel for grinding the external circle and end face of the large head end is matched with the grinding wheel for grinding the external cylindrical journal of the large head end. The application field of the invention is single grinding of multiple outer journals of camshafts, which can process multiple journals and big ends of camshafts at one time, improve processing efficiency, and ensure that the surface roughness of the processed workpiece is less than Rz 10.

Description

Combination electroplating CBN grinding wheel for camshaft grinding and manufacturing method thereof

technical field

The invention belongs to the field of abrasive abrasive tool design and manufacture, and relates to a combined electroplating CBN grinding wheel for camshaft grinding and a manufacturing method thereof.

Background technique

With the rapid development of my country's automobile industry, the demand for engine camshafts has also increased substantially, and the requirements for processing quality and efficiency of camshafts are getting higher and higher. In the current camshaft manufacturing process, some automobile manufacturers need to use a grinding wheel to grind multiple external journals of their camshafts in a single pass. At present, the process of grinding the outer journal of the camshaft on the market is the process of first turning or milling and then grinding the shaft diameter. Generally, there are 6-20 parts that need to be ground on the outer circle of the camshaft. lower. Moreover, the grinding wheel has shortcomings in the aspects of grinding linear speed, feed rate, difficult to control the size of each journal after grinding, and high surface roughness.

CBN grinding wheels for camshaft journal grinding can be divided into ceramic bond CBN grinding wheels and electroplated metal bond CBN grinding wheels according to the type of bond. Compared with the CBN grinding wheel with vitrified bond, the electroplating CBN grinding wheel has obvious advantages in the grinding of large allowance removal. This advantage is mainly reflected in the following aspects: the geometric accuracy of the profile surface can be guaranteed without dressing the grinding wheel during its service life, and the dressing cycle of the grinding wheel can be omitted; the abrasive maintains a certain height of the edge and directly contacts the workpiece, thereby Increase grinding efficiency; use electroplating bond to easily manufacture grinding wheels with complex surfaces such as curved surfaces and special shapes, without increasing too much manufacturing cost; multiple grinding wheels can be produced separately according to the requirements of grinding objects and finally assembled into special Single-shot grinding on the grinder to increase efficiency. Therefore, electroplated CBN grinding wheels are particularly suitable for high-efficiency, precise, and large-scale removal grinding of camshafts. Among them, the structural design of the grinding wheel base, the machining accuracy, the control of the thickness of the coating, the precise dressing after plating, and the dimensional consistency detection of the grinding wheel base and after plating are important factors in the manufacture of electroplated CBN grinding wheels for precision forming and grinding.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a combined electroplating CBN grinding wheel for camshaft grinding and a manufacturing method thereof. The invention manufactures the corresponding electroplating CBN grinding wheel by designing the base body shape of the grinding wheel, combining the abrasive selection process, the coating layer control process, the dimensional consistency detection technology of the coating base body and the finished product after plating, and the post-plating dressing technology of the grinding wheel. The application field of the invention is the single grinding of multiple external journals of the camshaft, which can process multiple journals and the big end of the camshaft at one time, improve the processing efficiency, and ensure that the surface roughness of the processed workpiece is less than Rz 10.

Based on the above object, the present invention adopts the following technical solutions:

A combined electroplating CBN grinding wheel for camshaft grinding, comprising a camshaft, a combined electroplating CBN grinding wheel sleeved on a main shaft for grinding different parts of the camshaft, and a guide wheel on the side of the camshaft away from the combined electroplating CBN grinding wheel For top connection, the combined electroplating CBN grinding wheel includes grinding wheel for grinding the outer circle and end face of the big head, grinding wheel for grinding the outer circle of the big head and several grinding wheels for grinding the outer cylindrical journal, among which the grinding wheel for grinding the outer circle and the end face of the big head and the grinding wheel for grinding the outer circle of the big head The profile of the round journal grinding wheel is suitable.

Further, there are four grinding wheels for grinding the outer cylindrical journal, the outer diameter is 550-630mm, and the inner hole diameter is 300-400mm.

Further, the outer circle of the grinding head end and the end face grinding wheel are one, and the outer diameter of the grinding wheel is 2.5-5mm smaller than that of the grinding wheel of the outer cylindrical journal, the diameter of the inner hole is 300-400mm, and the outer edge of one end face of the grinding wheel is provided with grooves in the circumferential direction. , the groove is a right-angled trapezoid, the height of the trapezoid is 3mm, the upper base is 4mm, and the lower base is 11mm.

Further, there is one grinding wheel for grinding the outer cylindrical journal of the large head end, and the outer diameter of the grinding wheel is 8-12 mm smaller than that of the grinding wheel for grinding the external cylindrical journal of the large head end. It is suitable for the grooves of the grinding wheel on the outer circle of the large head end and the end face grinding wheel.

A manufacturing method of combined electroplating CBN grinding wheel for camshaft grinding, comprising the following steps:

(1) According to the design of the camshaft, the grinding wheel for grinding the outer circle and end face of the large head end, the grinding wheel for grinding the external cylindrical journal and the grinding wheel for grinding the external cylindrical journal of the large head end, the grinding wheel for grinding the external circle and the end face of the large head end, and the grinding wheel for grinding the external cylindrical journal of the large head end The shape and surface are matched, and the corresponding physical object is processed according to the corresponding drawing;

(2) Machining the grinding wheel base in step (1), the outer diameter deviation of the real grinding wheel base is within 0.015mm, and the shape and position tolerance is within 0.002mm;

(3) Abrasive selection: use the upper screen and the lower screen to superimpose the double screen for particle size screening, so that the maximum deviation of the abrasive particle size is 0.02mm;

(4) Precision electroplating: electroplating the grinding wheel substrate in the order of electrochemical degreasing, pre-plating and sanding to obtain the grinding wheel. During electrochemical degreasing, the current is adjusted according to the electrolytic current density of 10-20A/dm ² , and an increase of 30s can be used. Remove the substrate by 0.005-0.01mm; during pre-plating, adjust the current according to the current density of 1-2A/dm ² , and increase it by 10min, the bottom layer can be increased by 0.003-0.006mm; sand is applied by burying sand method;

(5) Thickening: The grinding wheel after sanding is electroplated under the current density of 0.25-0.3 A/dm ² for 20-25 hours, the duty ratio is 70-80%, and the ratio of positive and negative pulse time is 4-6. The height deviation of the edge on both ends and the outer circular plane measured by the coke method is not more than 20μm, and the buried rate of the coating is 30-55%;

(6) Size trimming after plating: Use white corundum grinding wheel to trim the substrate after plating, and the size deviation of the profile should be less than 0.01mm;

(7) Abrasive layer detection: The three-coordinate detection method is adopted, and the ruby probe is selected as the detection probe to take points uniformly in the direction of the outer circle of the grinding wheel. According to the thickness direction of the grinding wheel, the data of two to four circles are taken, and the data points on each circle are used to simulate After the circle is synthesized, the value of its outer diameter is the required value; when the relative deviation of the outer diameter is greater than 0.015mm, the grinding wheel is reworked and trimmed; the relative deviation of the outer diameter is less than 0.015mm to meet the processing requirements.

Further, the pre-plating, sanding and thickening processes are all performed in a nickel-cobalt alloy plating solution, and the nickel-cobalt alloy plating solution has the following components: nickel sulfate: 230-320g/L, nickel chloride: 30-50g/L, boric acid : 30-55g/L, cobalt sulfate: 10-30g/L, brightener: 0.5-1.2g/L, wetting agent: 0.1-0.5g/L, solvent is water. The weight of abrasive used in the sanding process is 10000-25000cts, and the abrasive that is not attached after sanding can be recycled.

Further, the wetting agent is a kind of sodium lauryl sulfate or sodium ethylhexyl sulfate, and the brightener is made by mixing component A and component B, wherein component A is butynediol, Any of coumarin and propargyl alcohol, and component B is any one of saccharin, sodium benzene sulfinate, and sodium benzene sulfonate; the proportion of component A and component B is (0.3-0.6): 1 , preferably (2-3):5, the specific ratio can be 2:5 or 3:5;

Further, in the step (3), the mesh number of the upper screen is equal to the maximum value of the abrasive particle size, and the mesh number of the lower screen is equal to the minimum value of the abrasive particle size. The abrasive is used as the abrasive for the electroplated grinding wheel base.

5mm，每圈数据均匀取36个点。Further, the diameter of the ruby probe described in the step (7) is

5mm, 36 points are taken evenly for each circle.

Further, the base material of the grinding wheel is 45 steel or 40Cr steel.

Further, the abrasive is CBN, and the particle size is 60-100 mesh.

The combined electroplating CBN grinding wheel for camshaft grinding obtained by the above-mentioned manufacturing method has a shape and model number of 3LL1M.

In the above-mentioned grinding method of combined electroplating CBN grinding wheel for camshaft grinding, the linear speed of the combined electroplating CBN grinding wheel is 90-150m/s, and the feed rate is 4-8m/min.

The combined electroplating CBN grinding wheel obtained by the invention can satisfy the use of a linear speed of 150 m/s and a grinding feed rate of 4-10 m/min. There are no burns and cracks on the surface of the ground camshaft, the size, roundness and other indicators are within the tolerance range, and the roughness Rz can reach below 10μm, which can meet the surface quality requirements of the workpiece. The previous single grinding process for each shaft diameter was optimized, and the time required for grinding a single camshaft was reduced to less than 45 seconds, which was only 1/10 of the previous process time, and the multi-shaft diameter single grinding was successfully achieved. Efficient grinding.

The invention proposes a dimension control and detection technology during the machining of a group electroplated grinding wheel base body, which realizes the outer diameter detection of the group grinding wheel on the same machine tool and reduces rework operations.

Description of drawings

Fig. 1 is the structural representation of the present invention for grinding an external cylindrical journal grinding wheel, grinding a large head end external circle and an end face grinding wheel, and grinding a large head external cylindrical journal grinding wheel;

Fig. 2 is the profile view of grinding wheel of the present invention;

Figure 3 is a schematic diagram of the combination of grinding the outer circle of the large head end and the end face grinding wheel, and the grinding wheel of the outer cylindrical journal of the large head end;

Figure 4 is a schematic diagram of the detection position of the abrasive layer of the grinding wheel of the outer cylindrical journal;

Figure 5 is a schematic diagram of grinding after the camshaft electroplating CBN grinding wheel is assembled. In the figure, 1. Grinding the outer circle journal grinding wheel, 2. Grinding the outer circle of the big end and the end face grinding wheel, 21. Groove, 3. Grinding the outer circle of the big head Journal grinding wheel, 31. Protrusion, 4. Abrasive layer, 5. Ruby probe, 6. Guide wheel, 7. Camshaft, 8. Spindle.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings, but the protection scope of the present invention is not limited thereto.

Example 1

A combined electroplating CBN grinding wheel for camshaft grinding, comprising a camshaft 7, a combined electroplating CBN grinding wheel sleeved on the main shaft 8 for grinding different parts of the camshaft 7, and the camshaft 7 is away from a part of the combined electroplating CBN grinding wheel. The side guide wheel 6 is top-connected, and the combined electroplating CBN grinding wheel includes grinding the outer circle of the big head end and the end face grinding wheel 2, grinding the outer circle journal grinding wheel of the large head end 3 and a number of grinding outer circle journal grinding wheels 1, wherein the outer circle of the large head end is ground. And the profile of the end face grinding wheel 2 and the grinding wheel 3 of the outer cylindrical journal of the large head end are matched. In this embodiment, there are four grinding wheels 1 for grinding the outer cylindrical journal, the outer diameter is 590mm, the inner hole diameter is 370mm, and the thickness is 30-40mm;

The outer circle of the grinding head end and the end face grinding wheel 2 are one, the outer diameter of the grinding wheel is 586.57mm, the diameter of the inner hole is 370mm, and the thickness is 45-55mm. The outer edge is 3mm (the side of the grinding wheel and the end surface of the outer edge of the groove 21 are covered with the abrasive layer 4), the groove 21 is a right-angled trapezoid, the height of the trapezoid is 3mm, the upper base is 4mm, and the lower base is 11mm;

There is one grinding wheel 3 for grinding the outer cylindrical journal of the large end. The outer diameter of the grinding wheel is 580mm, the diameter of the inner hole is 370 mm, and the thickness is 13-20 mm. The outer edge of the grinding wheel 3 is provided with a protrusion 31 in the circumferential direction. The protrusion 31 is matched with the groove 21 of the grinding wheel 2 on the outer circle of the large head end and the end face grinding wheel 2;

Grinding the grooves 21 of the outer circle of the large head end and the end face grinding wheel 2, and the protrusions 31 of the grinding wheel 3 of the outer cylindrical journal of the large head end, this structure can effectively release the stress, reduce the weight of the grinding wheel, and optimize the mass distribution of the grinding wheel. The load of the abrasive layer 4 is reduced in the process of grinding the workpiece, which helps to increase the limit speed of the grinding wheel; in order to speed up the large-end grinding chips, the discharge of heat and the penetration of the coolant, and to maximize the use of the abrasive in the middle area of the grinding wheel for grinding , a groove 21 is machined at the junction of the combination of the two grinding wheels for processing the outer circle and the end face of the big end. The cross-sectional shape of the abrasive layer 4 of the grinding wheel can not only prevent the combined use, but also increase heat dissipation and cooling.

A manufacturing method of combined electroplating CBN grinding wheel for camshaft grinding, comprising the following steps:

(1) As shown in Figure 1, according to the diameter and relative position of the intake camshaft of the automobile engine, design the grinding wheel 2 for grinding the outer circle of the large head end and the end face, grinding wheel 1 for grinding the outer cylindrical journal and grinding wheel 3 for grinding the outer circular journal of the large head end , and process the corresponding substrate according to the corresponding drawings, the shape code of the grinding wheel substrate is 3LL1M;

(2) Machining the base of the grinding wheel in step (1) by rough turning - drilling - rough grinding plane inner hole - car surface - fine grinding inner hole, outer circle and end face. The key step of this process is to control the special grinding machine. Set up a fixed watch frame on the machine tool, put the watch head in the same position, point the pointer of the watch to a position every time you measure, observe the number in the X direction on the grinder to measure the distance between each grinding wheel The outer diameter deviation of the grinding wheel base is within 0.015mm, and the shape and position tolerance is within 0.002mm;

(3) Abrasive selection: Because the combined grinding wheel has strict requirements on the dimensional deviation between each grinding wheel, it is necessary to strictly control the abrasive particle size range on the basis of the control of the matrix, and the upper screen and the lower screen are used to superimpose. The particle size is sieved with double screens, so that the maximum deviation of the abrasive particle size is 0.02mm; taking the commonly used CBN60/70 mesh abrasive as an example, according to the national standard, the basic particle size deviation is between 212-250μm, and the upper limit screen size is 322μm, the lower limit screen size is 213μm, the difference between the largest and the smallest particles is basically 100μm, which is 0.1mm, this deviation cannot meet the requirement of the size deviation of ±0.01mm. Therefore, this application adopts the method of narrowing the particle size range of the abrasive used and sieving it multiple times. The 255 μm inspection sieve used for detecting the 50/60 mesh superhard abrasive in the national standard is used as the upper screen, and the 60/70 mesh superhard abrasive is detected. The 213μm inspection sieve is the lower screen, and the two inspection screens are placed on top of each other. The CBN60/70 mesh abrasive is placed on the upper inspection screen to start screening. Finally, the abrasive under the upper inspection screen and above the lower inspection screen is taken as the product. The basic particle size of the abrasive used is controlled at 213-255 μm, that is, the maximum deviation of the abrasive particle size is 0.02 mm. Abrasives of other particle sizes can be sieved in a similar manner. The grinding wheel substrate is subjected to electrochemical degreasing, fixture assembly, electrolytic activation, pre-plating, sanding, and thickening in sequence to manufacture an electroplated CBN grinding wheel.

(4) Precision electroplating: follow the order of fixture assembly, electrochemical degreasing, pre-plating, and sanding. After the electrochemical degreasing is completed, the non-plated part of the grinding wheel base is protected by a combination of self-adhesive paper and a special fixture, and the wire is connected to the non-reference surface, because the outer diameter of the grinding wheel base cannot be completely controlled in the same tolerance zone. , each grinding wheel will have a certain deviation relative to the required size difference, and the deviation is basically 0.015mm. Therefore, the partial compensation of the deviation needs to be realized through the electroplating process, which is mainly controlled by controlling the pretreatment time and the preplating time. According to the outer diameter data measured by the substrate, the one with the lower deviation of the size deviation is selected as the benchmark. During the pretreatment process, the excess substrate is electrolyzed by means of electrochemical degreasing of the substrate. time proportional. In addition, the grinding wheel with a small base can increase the thickness of the bottom layer by prolonging the pre-plating time. Among them, according to the electrolysis current density 10-20A/dm ² to adjust the current, increase 30s, can remove the matrix 0.005-0.01mm. During pre-plating, adjust the current according to the current density of 1-2A/dm ² , and increase the bottom layer by 0.003-0.006mm after adding 10min. When sanding, use the burying method to apply the sand, and cooperate with the sand cover to carry out the sand burying process. It is mainly to ensure that the outer circle is sanded once to ensure that the abrasive is arranged along the single layer of the matrix. The abrasive used in this grinding wheel is CBN, the particle size is 60/70 mesh, and the coating burial rate is set to 30-55%.

(5) Thickening: In order to keep the same height of the abrasive in each area as much as possible, the thickening process of the grinding wheel needs to use a bidirectional pulse power supply. The anode electrolyzes the parts with obvious tip effects such as arc protrusions, so as to achieve the purpose of uniform deposition thickness of the overall coating. The pulse power supply adjustment parameters are current density 0.25～0.3 A/dm ² , time 20～25h, duty ratio 70～80%, positive and negative pulse time ratio 4～6, take out after thickening. After the thickening is completed, the clamp and sticker are disassembled and placed in an oven, and the oven temperature is kept at 80° C. for 2 hours, that is, an abrasive layer 4 is formed on the grinding wheel base. The height deviation of the edge on the two end faces and the outer circular plane measured by the microscope focal method does not exceed 20μm. The grinding wheel profile after thickening treatment is shown in Figure 2 and Figure 3.

The pre-plating, sanding and thickening are all carried out in the nickel-cobalt alloy plating solution. The weight of the abrasive used in the sanding process is 10000-25000cts. After the electroplating, the unattached abrasive can be recycled and reused. The composition of the nickel-cobalt alloy plating solution is: Nickel sulfate: 230-320g/L, nickel chloride: 30-50g/L, boric acid: 30-55g/L, cobalt sulfate: 10-30g/L, brightener: 0.5-1.2g/L, wetting agent: 0.1 -0.5g/L, the solvent is water. The wetting agent is sodium lauryl sulfate, and the brightening agent is prepared by mixing component A and component B, wherein component A is butynediol, and component B is sodium benzene sulfinate; component A and component The mass of B is 3:5.

(6) Size dressing after plating: place the grinding wheel on a special machine tool, then find the 4 high points of the cylindrical abrasive layer, and use the installed white corundum grinding wheel to remove the high points of the knife, and the profile size deviation should be less than 0.01mm;

55mm的红宝石测头5，可有效减小磨损，且不会嵌入到磨料之间的空隙。在砂轮外圆方向上均匀取点，取点36个（见图4），按照砂轮厚度方向，取三圈数据，采用各自的36个数据点拟合成圆后，其外径数值便是要求的数值。当外径尺寸相对偏差大于0.015mm时，砂轮加工出的工件就会容易出现不均匀磨损，就需要进行返工修整。将型面外径尺寸相对偏差小于0.015mm，满足加工要求。(7) Abrasive layer detection: The abrasive particles of the abrasive layer of the electroplated grinding wheel are directly exposed to the outside, which increases the difficulty of detecting the outer diameter. Using the three-coordinate detection method, the detection probe is selected

The 55mm ruby probe 5 can effectively reduce wear and will not be embedded in the gap between the abrasives. Take the points evenly in the direction of the outer circle of the grinding wheel, and take 36 points (see Figure 4). According to the thickness direction of the grinding wheel, take the data of three circles. After fitting the 36 data points to form a circle, the value of the outer diameter is the required value. value of . When the relative deviation of the outer diameter is greater than 0.015mm, the workpiece processed by the grinding wheel will be prone to uneven wear, and it needs to be reworked. The relative deviation of the outer diameter of the profile is less than 0.015mm to meet the processing requirements.

(8) Dynamically balance the G1 grade of each grinding wheel. As shown in FIG. 5 , after the treatment, each grinding wheel is assembled and mounted on one main shaft 8 , the camshaft 7 is ground, and the other side of the camshaft 7 is abutted with the guide wheel 6 .

The camshaft 7 made of chilled cast iron is held up by a pallet, the rear side is fixed with a guide wheel 6, and the group of grinding wheels are clamped on the grinding wheel frame of the CNC grinding machine. According to the program prepared by the machine tool, the linear speed of the grinding wheel is kept at 90-150m/s, the feed speed is kept at 4-8m/min, and the coolant system is adjusted. The machine tool is started, and the camshaft 7 is subjected to high-efficiency removal and grinding of the camshaft.

Using multiple grinding wheels to grind the camshaft can achieve the goal of grinding six stations in a single pass. The single removal allowance can reach 2-4mm, the roughness is less than Rz10, and the single-piece processing time is only 40-45s. Under the processing conditions of ensuring the same removal amount, the single-piece grinding wheel can only grind a single station at a time. The processing time of the method is about 300s, and the processing time of the combined grinding wheel using other bonding agent types is 140-160s. The invention significantly reduces the grinding time of the camshaft. After processing 10-15 pieces, it is necessary to trim and sharpen the abrasive layer of the grinding wheel. The electroplated grinding wheel has the advantages of no trimming and high sharpness, which can effectively improve the production efficiency.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (7)

1. A combined electroplated CBN grinding wheel for grinding a camshaft is characterized by comprising the camshaft and a combined electroplated CBN grinding wheel sleeved on a main shaft and used for grinding different parts of the camshaft, wherein one side of the camshaft, which is far away from the combined electroplated CBN grinding wheel, is butted with a guide wheel; the number of the grinding wheels for grinding the outer circle shaft neck is four, the outer diameter is 550-630mm, and the inner hole diameter is 300-400 mm; the grinding wheel for grinding the excircle and the end face of the big head end is one, the grinding wheel is 2.5-5mm smaller than the outer diameter of the grinding wheel for grinding the excircle journal, the diameter of an inner hole is 300-400mm, grooves are circumferentially arranged at the outer edge of the excircle and the end face of the grinding wheel for grinding the excircle and the end face of the big head end, the grooves are in a right trapezoid shape, the grinding wheel for grinding the excircle journal of the big head end is one, the grinding wheel is 8-12mm smaller than the outer diameter of the grinding wheel for grinding the excircle journal, protrusions are circumferentially arranged at the outer edge of the end face of the grinding wheel for grinding the excircle and the end face of the big head end.

2. The method for manufacturing a composite electroplated CBN grinding wheel for grinding a camshaft as claimed in claim 1, characterized by comprising the steps of:

(1) grinding the excircle and end face of the big head end, grinding the excircle journal and grinding the excircle journal of the big head end according to the design of the camshaft, and processing a corresponding grinding wheel matrix according to a corresponding drawing;

(2) machining the grinding wheel matrix in the step (1) to enable the outer diameter deviation of the grinding wheel matrix to be within 0.015mm and form and position tolerance to be within 0.002 mm;

(3) abrasive material fine selection: the double screens which are overlapped by the upper screen and the lower screen are adopted for screening the grain diameter, so that the maximum deviation of the grain diameter of the grinding material is 0.02 mm;

(4) precision electroplating: electroplating the grinding wheel matrix according to the sequence of electrochemical oil removal, preplating and sanding to obtain the grinding wheel, wherein the electrolytic current density is 10-20A/dm during electrochemical oil removal²The current is adjusted, the current is increased by 30s, and the matrix can be removed by 0.005-0.01 mm; in preplating, the current density is 1-2A/dm²Regulating current, increasing for 10min, and increasing the bottom layer by 0.003-0.006 mm; when sanding, sanding by adopting a sand burying method;

(5) thickening: the current density of the sand-coated grinding wheel is 0.25-0.3A/dm²Electroplating for 20-25 h, wherein the duty ratio is 70-80%, the time ratio of positive pulse to negative pulse is 4-6, the deviation of the height of the edge on the two end surfaces and the excircle plane is not more than 20 mu m measured by a microscope quasi-focusing method, and the embedding rate of the coating is 30-55%;

(6) and (3) size trimming after plating: trimming the plated matrix by using a white corundum grinding wheel, wherein the size deviation of the molded surface is required to be less than 0.01 mm;

(7) and (3) detecting an abrasive layer: selecting a ruby measuring head as a detection probe to uniformly pick points in the excircle direction of the grinding wheel by adopting a three-coordinate detection method, taking two to four circles of data according to the thickness direction of the grinding wheel, and fitting the data points of each circle into a circle, wherein the outer diameter value of the circle is the required value; when the relative deviation of the outer diameter size is larger than 0.015mm, reworking and finishing the grinding wheel; when the relative deviation of the outer diameter size is less than 0.015mm, the processing requirement is met.

3. The manufacturing method of the combined electroplated CBN grinding wheel for grinding of the camshaft as claimed in claim 2, wherein the pre-plating, sanding and thickening are all performed in a nickel-cobalt alloy plating solution, the nickel-cobalt alloy plating solution comprises the following components: nickel sulfate: 230-320g/L, nickel chloride: 30-50g/L, boric acid: 30-55g/L, cobalt sulfate: 10-30g/L, brightener: 0.5-1.2g/L, wetting agent: 0.1-0.5g/L, and the solvent is water; the weight of the abrasive used in the sanding process is 10000-25000 cts; the wetting agent is one of sodium dodecyl sulfate or sodium ethylhexyl sulfate, and the brightening agent is prepared by mixing a component A and a component B, wherein the component A is any one of butynediol, coumarin and propiolic alcohol, and the component B is any one of saccharin, sodium benzene sulfinate and sodium benzene sulfonate; the mass ratio of component A and component B is (0.3-0.6): 1.

4. The method for manufacturing a combined electroplated CBN grinding wheel for grinding a camshaft as claimed in claim 2, wherein the mesh number of the upper screen is equal to the maximum value of the grain size of the abrasives, the mesh number of the lower screen is equal to the minimum value of the grain size of the abrasives, and the abrasives below the upper screen and above the lower screen are taken as the abrasives of the electroplated grinding wheel base body in the step (3).

5. The method for manufacturing the combined electroplated CBN grinding wheel for grinding the camshaft as claimed in claim 2, wherein the diameter of the ruby measuring head in the step (7) is 5mm, and 36 points are uniformly taken from each circle.

6. The method for manufacturing a combined electroplated CBN grinding wheel for grinding of camshafts as claimed in claim 2, wherein the material of the grinding wheel base is 45 steel or 40Cr steel.

7. The method for manufacturing a combined electroplated CBN grinding wheel for grinding a camshaft as claimed in claim 2, wherein the abrasive is CBN and has a particle size of 60 to 100 mesh.

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