ORDERLY-MICRO-GROOVED PCD GRINDING WHEEL FOR POSITIVE RAKE ANGLE PROCESSING AND METHOD FOR MAKING SAME

Abstract

Disclosed are an orderly-micro-grooved PCD grinding wheel for positive rake angle processing and a preparation method thereof. A PCD film is deposited on the outer circumferential surface of a wheel hub, and a plurality of microgrooves with high depth-width ratio and micro-grinding units with positive rake angles are orderly provided on the outer circumferential surface of the entire PCD film. The method includes: depositing the PCD film on the outer circumferential surface of the wheel hub by a HFCVD technique; and manufacturing a plurality of microgrooves with a high depth-width ratio (circumferential width: dozens of micrometers; depth: hundreds of micrometers) and an axial length that is equal to the thickness of the grinding wheel and a plurality of micro-grinding units with positive rake angles on the outer circumferential surface of the entire PCD film by water-jet guided laser technique, where the micro-grinding units and the microgrooves are orderly arranged.

Claims

1. An orderly-micro-grooved PCD grinding wheel for positive rake angle processing, comprising: a wheel hub; a PCD film; a plurality of micro-grinding units with a positive rake angle; and a plurality of microgrooves; wherein the PCD film with a thickness of 1-2 mm is deposited on an outer circumferential surface of the wheel hub; the microgrooves are provided on an outer circumferential surface of the PCD film, wherein each of the microgrooves has an axial length that is equal to a thickness of the grinding wheel, a circumferential width of 20-50 m, a depth of 500-800 m and a depth-width ratio of 10-40:1; respective micro-grinding units with the positive rake angle are provided between two adjacent microgrooves, and the microgrooves and the micro-grinding units are respectively arranged in an ordered manner; when the grinding wheel is configured to grind a workpiece, respective micro-grinding units are in contact with the workpiece in the positive rake angle to achieve positive rake angle processing; and the microgrooves are mainly configured to hold chips and store a liquid.

2. The PCD grinding wheel of claim 1, wherein the wheel hub is made of titanium alloy, and has a diameter of 100-200 mm and a thickness of 6-20 mm.

3. The PCD grinding wheel of claim 1, wherein respective micro-grinding units have an axial length that is equal to the thickness of the grinding wheel, a circumferential width of 80-150 m, a radial height of 500-800 m and a circumferential spacing of 100-200 m.

4. A method of manufacturing the PCD grinding wheel of claim 1, comprising: 1) depositing the PCD film with a thickness of 1-2 mm on the outer circumferential surface of the wheel hub by a HFCVD technique; 2) polishing the outer circumferential surface of the PCD film by ion beam polishing to obtain a surface roughness of the PCD film of 0.15-0.2 m; 3) processing the outer circumferential surface of the PCD film by water-jet guided laser preparation technology: and focusing a laser beam emitted by a laser head in a nozzle through a glass window on a water chamber; pressurizing the water chamber to allow a water jet to be ejected from the nozzle and to guide the transmission of the laser beam to the outer circumferential surface of the PCD film; offsetting the grinding wheel by a certain angle, and producing one microgroove with an axial length that is equal to the thickness of the grinding wheel, a circumferential width of 20-50 m, a depth of 500-800 m and a depth-width ratio of 10-40:1 according to a relative movement orbit of the water jet and the wheel hub; indexing the grinding wheel, and rotating an outer circumference of the PCD film through a circumferential width of one micro-grinding unit to carry out the processing of the next microgroove, wherein the micro-grinding unit with a positive rake angle is formed between the two microgrooves; and processing the micro-grinding unit to form a clearance angle; 4) repeating step (3) to form a plurality of microgrooves with high depth-width ratio and a plurality of ordered micro-grinding units with the positive rake angle at the entire circumference of the PCD film; wherein respective micro-grinding units are the same in size; and 5) subjecting the product prepared in step (4) to pickling and then ultrasonic cleaning in deionized water to produce the orderly-micro-grooved PCD grinding wheel for positive rake angle processing.

5. The method of claim 4, wherein the wheel hub is made of titanium alloy, and has a diameter of 100-200 mm and a thickness of 6-20 mm.

6. The method of claim 4, wherein respective micro-grinding units have an axial length that is equal to the thickness of the grinding wheel, a circumferential width of 80-150 m, a radial height of 500-800 m and a circumferential spacing of 100-200 m.

7. The method of claim 4, wherein in step (3), the micro-grinding units formed by processing the PCD film with the laser beam have the positive rake angle of 10-40 and the clearance angle of 20-50.

8. The method of claim 4, wherein in step (3), a laser device used in the water-jet guided laser technique is an Nd:YAG pulse laser, and the Nd:YAG pulse laser has a wavelength of 532 nm and a focused spot diameter of 30-100 m.

9. The method of claim 4, wherein in step (3), a pressure of the water chamber used in the water-jet guided laser technique is 2-4 MPa, and a diameter of the water jet is 20-50 m.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a three-dimensional view showing a grinding wheel hub after deposited with a polycrystalline diamond film on the outer circumferential surface.

[0035] FIG. 2 schematically shows the processing of a microgroove by water-jet guided laser technique.

[0036] FIG. 3 is a schematic diagram showing the grinding wheel provided with microgrooves on the outer circumference and a partially enlarged view thereof.

[0037] FIG. 4 is a schematic diagram showing the processing of a workpiece with a grinding wheel and a partially enlarged view showing a contact zone between the grinding wheel and the workpiece.

[0038] In the drawings:

[0039] 1wheel hub; 2PCD film; 3laser head; 4glass window; 5water chamber; 6nozzle; 7laser beam; 8water jet; 9micro-grinding unit; 10microgroove; 11positive rake angle; 12workpiece; and 13clearance angle.

DETAILED DESCRIPTION OF EMBODIMENTS

[0040] This application will be further illustrated with reference to the embodiments and drawings.

[0041] Referring to FIGS. 1-4, an orderly-micro-grooved PCD grinding wheel for positive rake angle processing includes a wheel hub 1, a PCD film 2, a plurality of micro-grinding units 9 with a positive rake angle 11 and a plurality of microgrooves 10 with a high depth-width ratio. The PCD film 2 with a thickness of 1-2 mm is deposited on an outer circumferential surface of the wheel hub 1. The microgrooves 10 which have an axial length that is equal to a thickness of the grinding wheel, a circumferential width of 20-50 m, a depth of 500-800 m and a depth-width ratio of 10-40:1 are provided on the outer circumferential surface of the PCD film 2. The micro-grinding unit 9 with the positive rake angle 11 is provided between two adjacent microgrooves 10, and the microgrooves 10 and the micro-grinding units 9 are both orderly arranged. When the grinding wheel is configured to grind a workpiece 12, the micro-grinding unit 9 is in contact with the workpiece 12 in the positive rake angle 11, which ensures that the micro-grinding unit 9 can be used to process the workpiece in a positive rake angle 11. The microgrooves 10 are mainly configured to hold chip and store grinding liquid. The micro-grinding units 9 with a positive rake angle 11 can process the workpiece in a positive rake angle, which reduces the grinding force ratio and the grinding temperature, effectively reducing the surface damage and greatly improving the grinding performance and efficiency.

[0042] The orderly-micro-grooved PCD grinding wheel for positive rake angle processing is manufactured as follows.

[0043] Step (1)

[0044] A wheel hub 1 was mechanically prepared from titanium alloy, and had a diameter of 100 mm and a thickness of 12 mm. A PCD film 2 with a thickness of 2 mm was deposited on an outer circumferential surface of the wheel hub 1 made of titanium alloy by a HFCVD technique, then the outer circumferential surface of the PCD film 2 was polished by ion beam polishing to obtain a surface roughness of the PCD film of 0.2 m. The prepared PCD film 2 was used as a whole, which facilitated the combination with the wheel hub 1, so that the prepared PCD film 2 can bear greater grinding force, and was less prone to falling off, improving the service life of the grinding wheel.

[0045] Step (2)

[0046] The outer circumferential surface of the PCD film 2 was processed by water-jet guided laser technique, where a laser beam 7 emitted by a laser head 3 was focused in a nozzle 6 through a glass window 4 on a water chamber 5. The water chamber 5 was pressurized to allow a water jet 8 to be ejected from the nozzle 6 and to guide the transmission of the laser beam 7 to the outer circumferential surface of the PCD film 2. The grinding wheel was offset by a certain angle, and a single microgroove 10 with an axial length (12 mm) that is equal to the thickness of the grinding wheel, a circumferential width of 20 m, a depth of 500 m and a depth-width ratio of 25 was manufactured by changing the relative movement orbit of the water jet 8 and the wheel hub 1. Then the grinding wheel was indexed, and the outer circumference of the PCD film 2 was rotated over 100 m, i.e., the circumferential width of a micro-grinding unit 9, to carry out the processing for the next microgroove 10. The micro-grinding unit 9 with a positive rake angle of 30 was formed between the two microgrooves 10. Then the micro-grinding unit 9 was processed to form a clearance angle 13 of 40. The micro-grinding unit 9 was configured to cut a workpiece in a positive rake angle during the grinding process, which reduced the grinding force ratio and the grinding temperature, effectively reducing the occurrence of surface micro-crack and greatly improving the grinding performance and efficiency. Meanwhile, the water-jet guided laser technique can effectively prevent the micro-grinding unit 9 from being graphitized, so that the micro-grinding unit 9 can provide better surface-cutting effect, greatly extending the service life of the grinding wheel and improving the surface quality.

[0047] Step (3)

[0048] Step (2) was repeated to form a plurality of microgrooves 10 with high depth-width ratio and a plurality of ordered micro-grinding units 9 with a positive rake angle 11 at the entire circumference of the PCD film 2, and respective micro-grinding units 9 were the same in size. The ordered arrangement of the microgrooves 10 and the micro-grinding units 9 greatly improved the chip-holding space and facilitated the formation of ordered chip-removing channels during the grinding process, so that the chip-removing capacity was improved, which made the grinding wheel less prone to blockage. Moreover, the grinding fluid was promoted to enter into the grinding zone to provide an improved cooling effect, reducing surface thermal damage and effectively improving the grinding quality and surface-processing precision. Meanwhile, respective micro-grinding units were identical in geometry and size, so that the number of micro-grinding units involved in grinding per unit area was significantly increased during the grinding process, and the cutting edge of each micro-grinding unit can participate in the grinding, which greatly increased the effective number of cutting edges and reduced the cutting depth of the single cutting edge, effectively improving the grinding precision and efficiency.

[0049] Step (4)

[0050] The prepared grinding wheel was subjected to pickling and then ultrasonic cleaning in deionized water for 15 min to form the orderly-micro-grooved PCD grinding wheel for positive rake angle processing.

[0051] It should be understood that the above embodiments are only illustrative of the invention and are not intended to limit the invention. In addition, various equivalent modifications and changes made by those skilled in the art without departing from the spirit of the invention fall within the scope of the invention defined by the appended claims.