Ultrasonic assisted processing device and drilling method for ceramic drilling

Abstract

The present invention discloses an ultrasonic assisted processing device and a drilling method for ceramic drilling, wherein the ultrasonic assisted processing device for ceramic drilling comprises a machine tool body, an ultrasonic generator, an ultrasonic shank and a grinding wheel; the machine tool body is connected to the ultrasonic shank through a machine tool spindle, and the ultrasonic shank also receives an electrical signal emitted by the ultrasonic generator; the grinding wheel comprises a connecting portion, a cylindrical portion and a gradient portion, the connecting portion is connected to the ultrasonic shank, one end of the cylindrical portion is connected to the connecting portion, and the other end is connected to the first end of the gradient portion; the cross-sectional diameter of the gradient portion decreases from the first end to the second end, and the centers of the first end and the second end of the gradient portion are located on the axis of the grinding wheel. The ultrasonic assisted processing device and the drilling method for ceramic drilling of the present invention have small wear on the grinding wheel, long service life of the grinding wheel, high working efficiency, good hole quality, high yield rate of workpieces, and can drill high hardness workpieces.

Description

Technical Field

[0001] The invention belongs to the field of ceramic processing, and in particular relates to an ultrasonic auxiliary processing device for ceramic drilling and a drilling method. Background Art

[0002] Ceramic materials have excellent properties of high temperature resistance, corrosion resistance and high strength, and are widely used in mechanical parts in the fields of electronic information, aerospace, chemical energy, etc. Holes are a common processing technology for ceramic materials, which mainly play the role of connection, positioning, and weight reduction.

[0003] The grinding wheels used in the existing ceramic drilling process are mostly standard parts in the shape of hollow drills. For example, a grinding wheel with a size of φ10mm can be used to process a 10mm hole. However, this type of grinding wheel has the following problems, which restricts the use and promotion of ceramic materials:

[0004] On the one hand, when drilling ceramic workpieces, there are many burrs, serious edge collapse, poor hole wall morphology and other problems, resulting in a low yield of ceramic workpieces;

[0005] On the other hand, it is necessary to select process parameters such as low speed, high feed and large cutting depth during processing, otherwise the grinding wheel will wear too much, seriously affecting the processing efficiency.

[0006] In addition, existing grinding wheels can only drill holes in ceramics with lower hardness, such as quartz ceramics. When drilling holes in ceramics with higher hardness, such as silicon nitride ceramics, the grinding wheels are easily deformed and need to be replaced frequently, which seriously affects the processing accuracy and efficiency of the holes. Summary of the invention

[0007] In view of the above problems, the present invention provides an ultrasonic assisted processing device and a drilling method for ceramic drilling. The ultrasonic assisted processing device and the drilling method for ceramic drilling have a long service life of the grinding wheel, can reduce the frequency of tool change, have a fast drilling rate, and have high work efficiency; can reduce the edge collapse problem of the exit and entrance of the hole on the workpiece, improve the hole morphology quality and yield rate of the ceramic workpiece; and can be used to drill high-hardness workpieces such as silicon nitride ceramic workpieces.

[0008] The ultrasonic assisted processing device for ceramic drilling provided by the present invention comprises a machine tool body, an ultrasonic generator, an ultrasonic tool handle and a grinding wheel; the machine tool body is connected to the ultrasonic tool handle through a machine tool spindle, and the ultrasonic tool handle also receives an electrical signal emitted by the ultrasonic generator; the grinding wheel comprises a connecting portion, a cylindrical portion and a gradient portion, the connecting portion is connected to the ultrasonic tool handle, one end of the cylindrical portion is connected to the connecting portion, and the other end is connected to the first end of the gradient portion; the cross-sectional diameter of the gradient portion decreases from the first end to the second end, and the centers of the first end and the second end of the gradient portion are located on the axis of the grinding wheel.

[0009] Preferably, the end face diameter of the first end of the gradient portion is equal to the cross-sectional diameter of the cylindrical portion; the end face diameter of the second end of the gradient portion is 1-2 mm, preferably, the end face diameter of the second end of the gradient portion is 1 mm.

[0010] Preferably, the ratio of the length of the gradient portion to the length of the cylindrical portion is (1:2)-(2:1); the cross-sectional diameter of the gradient portion decreases uniformly from the first end to the second end so that the gradient line is a straight line, or the cross-sectional diameter of the gradient portion decreases rapidly from the first end to the second end so that the curvature radius of the gradient line is 22-100 mm, wherein the gradient line refers to the outer contour line connecting the first end and the second end on the axial section of the gradient portion.

[0011] Preferably, the length of the gradient portion is 10-20 mm; the diameter of the end surface of the first end of the gradient portion is 6-10 mm; and the total length of the grinding wheel is not greater than 100 mm.

[0012] Preferably, the abrasive grains of the grinding wheel are diamond abrasive grains. Preferably, the grinding wheel comprises a grinding wheel base and electroplated diamond grains covering the surface of the grinding wheel base.

[0013] Preferably, the grinding wheel base is made of cast iron; and / or the outer surface of the grinding wheel base of the gradient portion and the cylindrical portion is covered with electroplated diamond particles.

[0014] Preferably, the ultrasonic vibration frequency of the ultrasonic generator is 14KHz-40KHz, the power is 10% to 100%, and the amplitude is 1.5 to 7μm; the ultrasonic tool handle includes a wireless transmission device, a transducer, and a horn; the wireless transmission device includes a transmitting ring and a receiving ring, the transmitting ring is used to receive the electrical signal emitted by the ultrasonic generator and transmit it to the receiving ring, and the receiving ring is connected to the transducer; the transducer converts electrical energy into mechanical energy to generate axial vibration, and the output end of the transducer is connected to the horn; the horn is connected to the grinding wheel.

[0015] Preferably, the machine tool body further includes a workbench for clamping workpieces, and the workbench is movable; the machine tool body further includes a cooling device for cooling.

[0016] The present invention also provides a drilling method using the ultrasonic assisted processing device for ceramic drilling, comprising the following steps: clamping the workpiece to a preset position, starting the machine tool body and the ultrasonic generator, driving the ultrasonic tool holder to work, and driving the grinding wheel to drill the workpiece.

[0017] Preferably, when drilling a silicon nitride ceramic workpiece: the drilling method is direct drilling, the cutting depth is 0.005-0.01 mm, the feed speed is not greater than 100 mm / min, and the machine tool spindle speed is not less than 20000 r / min.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The processing device of the present invention is used for ultrasonic assisted drilling. The grinding wheel includes a gradient portion. When in use, the end face of the grinding wheel forms a wedge-shaped contact structure with the workpiece, which has a strong sense of forward force, fast chip removal and heat dissipation, can reduce grinding wheel wear, and can reduce the occurrence of workpiece edge collapse.

[0020] (2) Using the ultrasonic assisted processing device for ceramic drilling of the present invention, in combination with direct drilling and drilling methods with small feed, small cutting depth and high rotation speed, it is possible to avoid edge collapse at the outlet caused by uneven force, improve the hole morphology quality of the workpiece, improve the workpiece yield, reduce grinding wheel wear, increase grinding wheel service life, and speed up drilling efficiency.

[0021] (3) The processing device and drilling method of the present invention can be used not only for hole processing of quartz ceramic workpieces, but also for hole processing of high-hardness ceramics such as silicon nitride ceramic workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an ultrasonic-assisted processing device for ceramic drilling in the present invention;

[0023] Figure 2 It is a schematic structural diagram of an ultrasonic knife handle in the present invention;

[0024] Figure 3 It is a structural schematic diagram of a grinding wheel in the present invention;

[0025] Figure 4 It is a structural schematic diagram of another grinding wheel in the present invention;

[0026] Figure 5 The silicon nitride ceramic workpiece is obtained after drilling using the device and method of Example 1 of the present invention.

[0027] Among them, 1-machine tool body, 11-machine tool column, 12-machine tool horizontal column, 13-machine tool spindle, 2-ultrasonic tool handle, 20-mounting ring, 211-transmitting ring, 212-receiving ring, 22-transducer, 23-amplifier, 3-grinding wheel, 31-cylindrical part, 32-gradient part, 320-gradient line, 33-connecting part, 4-ultrasonic generator, 5-cooling device, 6-workbench, 7-workpiece. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The present invention provides an ultrasonic auxiliary processing device for ceramic drilling, comprising a machine tool body 1, an ultrasonic generator 4, an ultrasonic tool holder 2 and a grinding wheel 3.

[0030] The machine tool body 1 is a CNC machine tool, preferably a five-axis linkage machine tool. Specifically, the machine tool body 1 includes a machine tool column 11, a machine tool column 12, and a machine tool spindle 13. The machine tool column 11 is vertically arranged, the machine tool column 12 is horizontally arranged and connected to the machine tool column 11, and the machine tool spindle 13 is vertically arranged on the machine tool column 12.

[0031] The machine tool body 1 further includes a workbench 6 for clamping a workpiece 7 . The workbench 6 is disposed below the machine tool spindle 13 , and the workbench 6 can move horizontally.

[0032] The machine tool body 1 is connected to the ultrasonic tool handle 2 through the machine tool spindle 13 . Specifically, the ultrasonic tool handle 2 is arranged below the machine tool spindle 13 and is connected to the machine tool spindle 13 through a mounting ring 20 . The ultrasonic tool handle 2 also receives the electrical signal emitted by the ultrasonic generator 4 .

[0033] The ultrasonic generator 4 has an ultrasonic vibration frequency of 14KHz-40KHz, a power of 10%-100%, and an amplitude of 1.5-7μm.

[0034] The ultrasonic knife handle 2 includes a wireless transmission device, a transducer 22, and a horn 23. The wireless transmission device includes a transmitting ring 211 and a receiving ring 212, wherein the transmitting ring 211 is used to receive the electrical signal emitted by the ultrasonic generator 4 and transmit it to the receiving ring 212, and the receiving ring 212 is connected to the transducer 22.

[0035] The transducer 22 is a reverse piezoelectric effect transducer 22 containing piezoelectric ceramics, which can convert electrical energy into mechanical energy and generate mechanical vibration in the axial direction. The output end of the transducer 22 is connected to the horn 23, and the horn 23 amplifies the vibration after receiving it.

[0036] The horn 23 is connected to the grinding wheel 3 to drive the grinding wheel 3 to vibrate axially. Specifically, the lower end of the horn 23 is fixed to the upper end of the grinding wheel 3 through a connecting plate (not shown in the figure) and a locking nut (not shown in the figure).

[0037] The grinding wheel 3 includes a connecting portion 33, a cylindrical portion 31 and a gradient portion 32. The connecting portion 33 is connected to the ultrasonic knife handle 2, one end of the cylindrical portion 31 is connected to the connecting portion 33, and the other end is connected to the first end of the gradient portion 32. The end surface diameter of the first end of the gradient portion 32 is equal to the cross-sectional diameter of the cylindrical portion 31. The length ratio of the gradient portion 32 to the length of the cylindrical portion 31 is (1:2)-(2:1).

[0038] It is worth noting that the end face and cross section mentioned in the present invention refer to the surface perpendicular to the axial direction, and the length refers to the length along the axial direction. Here, the division of the connecting portion 33, the cylindrical portion 31 and the gradient portion 32 of the grinding wheel 3 is a division made along the axial direction of the grinding wheel 3. Preferably, the cylindrical portion 31 and the gradient portion 32 of the grinding wheel 3 are integrally arranged, and further preferably, the connecting portion 33, the cylindrical portion 31 and the gradient portion 32 of the grinding wheel 3 are integrally arranged. In addition, the end face of the gradient portion described in the present invention can be regarded as a cross section of the gradient portion at a special position (the first end and the second end of the gradient portion). It is called an end face for the convenience of describing the radial dimensions of the first end and the second end of the gradient portion. The end face is not necessarily exposed to the outside and can be seen. For example, the cylindrical portion 31 of the present invention is integrally arranged with the gradient portion 32, then the first end face of the gradient portion 32 is invisible, and the second end of the gradient portion 32 can be seen. When in use, the second end of the gradient portion 32 faces the workpiece.

[0039] The cross-sectional diameter of the gradient portion 32 decreases from the first end to the second end, and the centers of the first end and the second end of the gradient portion 32 are located on the axis of the grinding wheel 3. Specifically, the cross-sectional diameter of the gradient portion 32 decreases uniformly from the first end to the second end so that the gradient line 320 is a straight line, or the cross-sectional diameter of the gradient portion 32 decreases rapidly from the first end to the second end so that the curvature radius of the gradient line 320 is 22-100 mm, wherein the gradient line 320 refers to the outer contour line connecting the first end and the second end on the axial cross section of the gradient portion 32.

[0040] The diameter of the end surface of the second end of the gradient portion 32 is 1-2 mm, preferably, the diameter of the end surface of the second end of the gradient portion 32 is 1 mm. The length of the gradient portion 32 is 10-20 mm; the diameter of the end surface of the first end of the gradient portion 32 is 6-10 mm. The total length of the grinding wheel is not greater than 100 mm, preferably 50 mm, 60 mm or 70 mm. Preferably, the length of the connecting portion 33 is not less than the sum of the lengths of the gradient portion 32 and the cylindrical portion 31.

[0041] The abrasive grains of the grinding wheel 3 are diamond abrasive grains. The gradient portion 32 and the cylindrical portion 31 of the grinding wheel 3 of the present invention are solid structures. Further, the entire grinding wheel is a solid structure. Specifically, the grinding wheel 3 can be made entirely of diamond abrasive grains from the inside to the outside, or diamond grains can be electroplated outside the grinding wheel base. Preferably, the grinding wheel 3 includes a grinding wheel base and electroplated diamond grains covering the surface of the grinding wheel base, and the material of the grinding wheel base is cast iron. Further preferably, the outer surface of the grinding wheel base of the gradient portion 32 and the cylindrical portion 31 is covered with electroplated diamond grains, and the outer surface of the grinding wheel base of the connecting portion 33 is not covered with electroplated diamond grains.

[0042] It is worth noting that the description here about "the grinding wheel 3 includes a grinding wheel base and electroplated diamond particles covering the surface of the grinding wheel base" is a division made along the radial direction of the grinding wheel 3, and the division here is mainly for the convenience of describing the material of the grinding wheel 3. The above description about "the grinding wheel 3 includes a connecting portion 33, a cylindrical portion 31 and a gradient portion 32" is a division made along the axial direction of the grinding wheel, mainly for the convenience of describing the dimensions of each part in the axial direction of the grinding wheel 3. Preferably, the grinding wheel base of the connecting portion 33, the cylindrical portion 31 and the gradient portion 32 of the grinding wheel 3 are arranged as one piece; further preferably, the cross-section of the grinding wheel base of the connecting portion 33 is the same as the cross-section of the grinding wheel base of the cylindrical portion 31, that is, both are circular and have the same radius. The electroplated diamond particles covering the outer surface of the grinding wheel base of the cylindrical portion 31 and the gradient portion 32 are also integrally arranged (the electroplated diamond particles mentioned here as integrally arranged do not mean that the same particles cover the grinding wheel base of the cylindrical portion and the gradient portion, but mean that the overall surface layer formed by the electroplated diamond particles covering the outer surface of the grinding wheel base of the cylindrical portion 31 and the gradient portion 32 is continuous). Considering cost issues, the outer surface of the grinding wheel base of the connecting portion 33 is no longer covered with electroplated diamond particles.

[0043] The machine tool body 1 further comprises a cooling device 5 for cooling, and the cooling device 5 can cool down the high temperature caused by the drilling work by means of a coolant.

[0044] The present invention also provides a drilling method using the ultrasonic assisted processing device for ceramic drilling, comprising the following steps: clamping the workpiece 7 to a preset position so that the grinding wheel 3 can drill holes at the positions on the workpiece 7 where holes need to be drilled, and after the clamping is completed, the workpiece 7 shakes ≤0.02mm, and the grinding wheel 3 jumps ≤0.02mm; starting the machine tool body 1 and the ultrasonic generator 4, driving the ultrasonic tool handle 2 to work, and driving the grinding wheel 3 to drill the workpiece 7. When the grinding wheel 3 drills the workpiece 7: the drilling method is direct drilling, the cutting depth is 0.005-0.05mm, the feed speed is not more than 300mm / min, and the rotation speed of the machine tool spindle 13 is not less than 20000r / min.

[0045] The ultrasonic assisted ceramic drilling device of the present invention can be used for drilling quartz ceramic workpieces and silicon nitride ceramic workpieces. After the ceramic workpiece 7 is drilled using the ultrasonic assisted ceramic drilling device and the drilling method of the present invention, the yield of the ceramic workpiece 7 is ≥95%, and the total area of ​​the edge collapse of the hole is ≤0.8mm.

[0046] Example 1

[0047] This embodiment provides an ultrasonic-assisted machining device for ceramic drilling, comprising a machine tool body 1 , an ultrasonic generator 4 , an ultrasonic tool holder 2 and a grinding wheel 3 .

[0048] The machine tool body 1 is a CNC machine tool, preferably a five-axis linkage machine tool. Specifically, the machine tool body 1 includes a machine tool column 11, a machine tool column 12, and a machine tool spindle 13. The machine tool column 11 is vertically arranged, the machine tool column 12 is horizontally arranged and connected to the machine tool column 11, and the machine tool spindle 13 is vertically arranged on the machine tool column 12.

[0049] The machine tool body 1 further includes a workbench 6 for clamping a workpiece 7 . The workbench 6 is disposed below the machine tool spindle 13 , and the workbench 6 can move horizontally.

[0050] The machine tool body 1 is connected to the ultrasonic tool handle 2 through the machine tool spindle 13 . Specifically, the ultrasonic tool handle 2 is arranged below the machine tool spindle 13 and is connected to the machine tool spindle 13 through a mounting ring 20 . The ultrasonic tool handle 2 also receives the electrical signal emitted by the ultrasonic generator 4 .

[0051] The ultrasonic vibration frequency of the ultrasonic generator 4 is adjustable within the range of 14KHz-40KHz, preferably 25080HZ; the power is adjustable within the range of 10%-100%, preferably 80%; and the amplitude is adjustable within the range of 1.5-7μm.

[0052] The ultrasonic knife handle 2 includes a wireless transmission device, a transducer 22, and a horn 23. The wireless transmission device includes a transmitting ring 211 and a receiving ring 212, wherein the transmitting ring 211 is used to receive the electrical signal emitted by the ultrasonic generator 4 and transmit it to the receiving ring 212, and the receiving ring 212 is connected to the transducer 22.

[0053] The transducer 22 is a reverse piezoelectric effect transducer 22 containing piezoelectric ceramics, which can convert electrical energy into mechanical energy and generate mechanical vibration in the axial direction. The output end of the transducer 22 is connected to the horn 23, and the horn 23 amplifies the vibration after receiving it.

[0054] The horn 23 is connected to the grinding wheel 3 to drive the grinding wheel 3 to vibrate axially. Specifically, the lower end of the horn 23 is fixed to the upper end of the grinding wheel 3 through a connecting plate (not shown in the figure) and a locking nut (not shown in the figure).

[0055] The grinding wheel 3 includes a connecting portion 33, a cylindrical portion 31 and a gradient portion 32. The connecting portion 33 is connected to the ultrasonic knife handle 2, one end of the cylindrical portion 31 is connected to the connecting portion 33, and the other end is connected to the first end of the gradient portion 32. The end surface diameter of the first end of the gradient portion 32 is equal to the cross-sectional diameter of the cylindrical portion 31. The length ratio of the gradient portion 32 to the length of the cylindrical portion 31 is (1:2)-(2:1), preferably 1:2, 1:1.6 or 2:1.

[0056] The cross-sectional diameter of the gradient portion 32 decreases from the first end to the second end, and the centers of the first end and the second end of the gradient portion 32 are located on the axis of the grinding wheel 3. Specifically, the cross-sectional diameter of the gradient portion 32 decreases rapidly from the first end to the second end so that the curvature radius of the gradient line 320 is 22-100 mm, wherein the gradient line 320 refers to the outer contour line connecting the first end and the second end on the axial section of the gradient portion 32. The grinding wheel of this embodiment can obtain the required abrasive grain speed and achieve high-quality drilling for high-hardness workpieces.

[0057] The end face diameter of the second end of the gradient portion 32 is 1-2mm, preferably 1mm. The length of the gradient portion 32 is 10-20mm; the diameter of the first end of the gradient portion 32 is 6-10mm. As a preferred embodiment, when the length of the gradient portion 32 is 10mm, the diameter of the first end is 6mm, the radius of curvature of the gradient line is 22.37mm, and the length of the cylindrical portion is 16mm-20mm. As another preferred embodiment, when the length of the gradient portion is 20mm, the diameter of the first end is 10mm, the radius of curvature of the gradient line is 100mm, and the length of the cylindrical portion is 10mm. Preferably, for processing stability, the total length of the grinding wheel is not more than 100mm, preferably 50mm, 60mm or 70mm. Preferably, the length of the connecting portion 33 is not less than the sum of the lengths of the gradient portion 32 and the cylindrical portion 31.

[0058] Figure 3-4 They are two types of grinding wheel structures in this embodiment, and the units of the dimensions marked in the figures are mm.

[0059] The abrasive grains of the grinding wheel 3 are diamond abrasive grains. The gradient portion 32 and the cylindrical portion 31 of the grinding wheel 3 are solid structures. Further, the entire grinding wheel is a solid structure. Specifically, the grinding wheel 3 can be made entirely of diamond abrasive grains from the inside to the outside, or diamond grains can be electroplated outside the grinding wheel base. Preferably, the grinding wheel 3 includes a grinding wheel base and electroplated diamond grains covering the surface of the grinding wheel base, and the material of the grinding wheel base is cast iron. Further preferably, the outer surfaces of the grinding wheel base of the gradient portion 32 and the cylindrical portion 31 are all covered with electroplated diamond grains, and the outer surface of the grinding wheel base of the connecting portion 33 is not covered with electroplated diamond grains.

[0060] The machine tool body 1 further comprises a cooling device 5 for cooling, and the cooling device 5 can cool down the high temperature caused by the drilling work by means of a coolant.

[0061] The present invention also provides a drilling method using the ultrasonic assisted processing device for ceramic drilling to drill a silicon nitride ceramic workpiece 7, wherein the density of the silicon nitride ceramic workpiece is 3.1 to 3.3 g / cm 3 , elastic modulus is 266GPa, and flexural strength at room temperature is 750~760MPa.

[0062] Specifically, the following steps are included: clamping the workpiece 7 to a preset position, such as Figure 1 As shown, the workpiece 7 is clamped on the workbench 6, and the upper end surface of the workpiece 7 forms a reference line with the lower end surface of the grinding wheel 3. After the clamping is completed, the shaking of the workpiece 7 is ≤0.02mm, and the jumping of the grinding wheel 3 is ≤0.02mm; the machine tool body 1 and the ultrasonic generator 4 are started, the ultrasonic tool holder 2 is driven to work, and the grinding wheel 3 is driven to drill the workpiece 7. When the grinding wheel 3 drills the workpiece 7: the drilling method is direct drilling, the cutting amount is 0.005-0.01mm, the feed speed is not more than 100mm / min, and the speed of the machine tool spindle 13 is not less than 20000r / min, preferably 20000r / min-25000r / min.

[0063] Example 2

[0064] This embodiment provides an ultrasonic-assisted machining device for ceramic drilling, comprising a machine tool body 1 , an ultrasonic generator 4 , an ultrasonic tool holder 2 and a grinding wheel 3 .

[0065] The machine tool body 1 is a CNC machine tool, preferably a five-axis linkage machine tool. Specifically, the machine tool body 1 includes a machine tool column 11, a machine tool column 12, and a machine tool spindle 13. The machine tool column 11 is vertically arranged, the machine tool column 12 is horizontally arranged and connected to the machine tool column 11, and the machine tool spindle 13 is vertically arranged on the machine tool column 12.

[0066] The machine tool body 1 further includes a workbench 6 for clamping a workpiece 7 . The workbench 6 is disposed below the machine tool spindle 13 , and the workbench 6 can move horizontally.

[0067] The machine tool body 1 is connected to the ultrasonic tool handle 2 through the machine tool spindle 13 . Specifically, the ultrasonic tool handle 2 is arranged below the machine tool spindle 13 and is connected to the machine tool spindle 13 through a mounting ring 20 . The ultrasonic tool handle 2 also receives the electrical signal emitted by the ultrasonic generator 4 .

[0068] The ultrasonic generator 4 has an ultrasonic vibration frequency of 25080 Hz, a power of 80%, and an amplitude of 0.5-7 μm.

[0069] The ultrasonic knife handle 2 includes a wireless transmission device, a transducer 22, and a horn 23. The wireless transmission device includes a transmitting ring 211 and a receiving ring 212, wherein the transmitting ring 211 is used to receive the electrical signal emitted by the ultrasonic generator 4 and transmit it to the receiving ring 212, and the receiving ring 212 is connected to the transducer 22.

[0070] The transducer 22 is a reverse piezoelectric effect transducer 22 with piezoelectric ceramics, which can convert electrical energy into mechanical energy and generate mechanical vibration in the axial direction. The output end of the transducer 22 is connected to the horn 23, which amplifies the vibration after receiving it.

[0071] The horn 23 is connected to the grinding wheel 3 to drive the grinding wheel 3 to vibrate axially. Specifically, the lower end of the horn 23 is fixed to the upper end of the grinding wheel 3 through a connecting plate (not shown in the figure) and a locking nut (not shown in the figure).

[0072] The grinding wheel 3 includes a connecting portion 33, a cylindrical portion 31 and a gradient portion 32. The connecting portion 33 is connected to the ultrasonic knife handle 2, one end of the cylindrical portion 31 is connected to the connecting portion 33, and the other end is connected to the first end of the gradient portion 32. The end surface diameter of the first end of the gradient portion 32 is equal to the cross-sectional diameter of the cylindrical portion 31. The length ratio of the gradient portion 32 to the length of the cylindrical portion 31 is (1:2)-(2:1).

[0073] The cross-sectional diameter of the gradient portion 32 decreases from the first end to the second end, and the centers of the first end and the second end of the gradient portion 32 are located on the axis of the grinding wheel. Specifically, the cross-sectional diameter of the gradient portion 32 decreases uniformly from the first end to the second end so that the gradient line 320 is a straight line, or the cross-sectional diameter of the gradient portion 32 decreases rapidly from the first end to the second end so that the curvature radius of the gradient line 320 is 22-100 mm, wherein the gradient line 320 refers to the outer contour line connecting the first end and the second end on the axial cross section of the gradient portion 32.

[0074] The diameter of the second end of the gradient portion 32 is 1-2 mm. The length from the first end to the second end of the gradient portion 32 is 10-20 mm; the diameter of the first end of the gradient portion 32 is 6-10 mm. Preferably, for processing stability, the total length of the grinding wheel is not greater than 100 mm, preferably 50 mm, 60 mm or 70 mm. Preferably, the length of the connecting portion 33 is not less than the sum of the lengths of the gradient portion 32 and the cylindrical portion 31.

[0075] The abrasive grains of the grinding wheel 3 are diamond abrasive grains. The gradient portion 32 and the cylindrical portion 31 of the grinding wheel 3 are solid structures. Further, the entire grinding wheel is a solid structure. Specifically, the grinding wheel 3 can be made entirely of diamond abrasive grains from the inside to the outside, or diamond grains can be electroplated outside the grinding wheel base. Preferably, the grinding wheel 3 includes a grinding wheel base and electroplated diamond grains covering the surface of the grinding wheel base, and the material of the grinding wheel base is cast iron. Further preferably, the outer surfaces of the grinding wheel base of the gradient portion 32 and the cylindrical portion 31 are all covered with electroplated diamond grains, and the outer surface of the grinding wheel base of the connecting portion 33 is not covered with electroplated diamond grains.

[0076] The machine tool body 1 further comprises a cooling device 5 for cooling, and the cooling device 5 can cool down the high temperature caused by the drilling work by means of a coolant.

[0077] The present invention also provides a drilling method using the ultrasonic assisted processing device for ceramic drilling, and drilling a quartz ceramic workpiece 7, comprising the following steps: clamping the workpiece 7 to a preset position, clamping the workpiece 7 to a workbench 6, and the upper end surface of the workpiece 7 and the lower end surface of the grinding wheel 3 form a reference line, the workpiece 7 shakes ≤0.02mm, and the grinding wheel 3 jumps ≤0.02mm; starting the machine tool body 1 and the ultrasonic generator 4, driving the ultrasonic tool handle 2 to work, and driving the grinding wheel 3 to drill the workpiece 7. When the grinding wheel 3 drills the workpiece 7: the drilling method is direct drilling, the cutting depth is 0.03-0.05mm, the feed speed is not more than 300mm / min, and the speed of the machine tool spindle 13 is 25000r / min.

[0078] Comparative Example 1

[0079] The grinding wheel of this comparative example adopts a φ14mm diamond hollow drill, a spindle speed of 4000r / min, a feed speed of 120mm / min, a feed amount of 0.05mm, an ultrasonic vibration frequency of 28580HZ, and a power of 80%, to directly drill a silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as Example 1.

[0080] After testing, it was found that when the comparative example was processed to 0.5 mm, the hollow diamond grinding wheel was de-sanded and the grinding wheel was severely worn, and the silicon nitride ceramic workpiece could not be processed further.

[0081] Comparative Example 2

[0082] The grinding wheel of this comparative example uses a φ4.5mm diamond hollow drill, a spindle speed of 4000r / min, a feed speed of 300mm / min, a feed amount of 0.05mm, an ultrasonic vibration frequency of 26550HZ, and a power of 80% to perform circular drilling on the silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as Example 1.

[0083] After testing, it was found that when the comparative example was processed to 1 mm, the hollow diamond grinding wheel was de-sanded and the grinding wheel was severely worn, and the silicon nitride ceramic workpiece could not be processed further.

[0084] Comparative Example 3

[0085] The grinding wheel of this comparative example adopts a φ8mm diamond cylindrical grinding wheel, a spindle speed of 4000r / min, a feed speed of 300mm / min, a feed amount of 0.05mm, an ultrasonic vibration frequency of 26400HZ, and a power of 80%, and performs circular drilling on the silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as those in Example 1.

[0086] After testing, it was found that when the comparative example was processed to 0.2 mm, the diamond cylindrical grinding wheel was de-sanded, severely worn, and bounced up, making it impossible to continue processing the silicon nitride ceramic workpiece.

[0087] Comparative Example 4

[0088] The grinding wheel of this comparative example adopts a φ6mm PDC cylindrical grinding wheel, a spindle speed of 4000r / min, a feed speed of 90mm / min, a feed amount of 0.05mm, an ultrasonic vibration frequency of 27115HZ, and a power of 80%, and performs circumferential drilling on a silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as those in Example 1.

[0089] After testing, it was found that when the PCD cylindrical grinding wheel of this comparative example was processed to 2 mm, it was broken and severely damaged, and it was impossible to continue processing the silicon nitride ceramic workpiece.

[0090] Comparative Example 5

[0091] The grinding wheel of this comparative example adopts a φ9.5mm diamond columnar grinding wheel, a spindle speed of 4000r / min, a feed speed of 60mm / min, a feed amount of 0.05mm, an ultrasonic vibration frequency of 24145HZ, and a power of 80%, and performs circular drilling on the silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as those in Example 1.

[0092] After testing, it was found that when the diamond columnar grinding wheel in this comparative example was processed to 0.3 mm, it was severely worn and could not continue to process the silicon nitride ceramic workpiece.

[0093] Comparative Example 6

[0094] The grinding wheel of this comparative example adopts a φ8mm diamond hollow drill, a spindle speed of 25000r / min, a feed speed of 50mm / min, a feed amount of 0.05mm, an ultrasonic vibration frequency of 20kHz, and a power of 80%, to directly drill a silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as those in Example 1.

[0095] After testing, it was found that when drilling a silicon nitride ceramic workpiece in this comparative example, the grinding wheel was severely worn and could not process a through hole.

[0096] Comparative Example 7

[0097] The grinding wheel of this comparative example adopts a diamond grinding wheel with a large end of φ6mm and a tip of φ3mm, a spindle speed of 20000r / min, a feed speed of 100mm / min, a feed amount of 0.01mm, an ultrasonic vibration frequency of 20kHz, and a power of 80%, to directly drill a silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as those in Example 1.

[0098] According to the test, when the diamond grinding wheel of this comparative example is used to drill a silicon nitride ceramic workpiece, the grinding wheel is severely worn and cannot process a through hole.

[0099] Comparative Example 8

[0100] The grinding wheel of this comparative example adopts a diamond grinding wheel with a large end of φ6mm and a tip of φ2mm, a spindle speed of 20000r / min, a feed speed of 1000mm / min, a feed amount of 0.01mm, an ultrasonic vibration frequency of 20kHz, and a power of 80%, to directly drill a silicon nitride ceramic workpiece. Among them, the silicon nitride ceramic workpiece processed in this comparative example is the same as the silicon nitride ceramic workpiece in Example 1. Other devices and processes are the same as those in Example 1.

[0101] According to the test, when the diamond grinding wheel of this comparative example is used to drill a silicon nitride ceramic workpiece, the grinding wheel is severely worn and cannot process a through hole.

[0102] In summary, it can be seen that only by adopting the processing device and drilling method of the present invention can hole processing of high hardness workpieces such as silicon nitride ceramic workpieces be achieved, and high-quality, high-precision through holes can be obtained. The grinding wheel wear is light, and there is no need to frequently replace the grinding wheel. The processing efficiency is high and the yield rate is high.

[0103] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still modify the technical solutions recorded in the above embodiments, or replace part or all of the technical features therein with equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. An ultrasonic assisted processing device for ceramic drilling, characterized in that: It includes a machine tool body, an ultrasonic generator, an ultrasonic tool holder and a grinding wheel; The machine tool body is connected to the ultrasonic tool handle through the machine tool spindle, and the ultrasonic tool handle also receives the electrical signal emitted by the ultrasonic generator; The grinding wheel comprises a connecting portion, a cylindrical portion and a gradient portion, wherein the connecting portion is connected to the ultrasonic tool handle, one end of the cylindrical portion is connected to the connecting portion, and the other end is connected to the first end of the gradient portion; The cross-sectional diameter of the gradual portion decreases from the first end to the second end, and the centers of the first end and the second end of the gradual portion are located on the axis of the grinding wheel; The ratio of the length of the gradient portion to the length of the cylindrical portion is (1:2)-(2:1); The cross-sectional diameter of the gradient portion decreases rapidly from the first end to the second end so that the curvature radius of the gradient line is 22-100 mm, wherein the gradient line refers to the outer contour line connecting the first end and the second end on the axial cross section of the gradient portion; The length of the gradient portion is 10-20 mm; The end surface diameter of the first end of the gradient portion is 6-10 mm; The total length of the grinding wheel is not more than 100 mm; The ultrasonic generator has an ultrasonic vibration frequency of 14KHz-40KHz, a power of 10%-100%, and an amplitude of 1.5-7μm.

2. The ultrasonic assisted machining device for ceramic drilling according to claim 1, characterized in that: The end surface diameter of the first end of the gradient portion is equal to the cross-sectional diameter of the cylindrical portion; The diameter of the end surface of the second end of the gradient portion is 1-2 mm.

3. The ultrasonic assisted machining device for ceramic drilling according to claim 1, characterized in that: The abrasive grains of the grinding wheel are diamond abrasive grains.

4. The ultrasonic assisted machining device for ceramic drilling according to claim 3, characterized in that: The material of the grinding wheel base is cast iron; And / or, the outer surface of the grinding wheel base of the gradient portion and the cylindrical portion is covered with electroplated diamond particles.

5. The ultrasonic assisted machining device for ceramic drilling according to claim 1, characterized in that: The ultrasonic knife handle includes a wireless transmission device, a transducer, and a horn; The wireless transmission device comprises a transmitting ring and a receiving ring, wherein the transmitting ring is used to receive the electrical signal transmitted by the ultrasonic generator and transmit it to the receiving ring, and the receiving ring is connected to the transducer; The transducer converts electrical energy into mechanical energy and performs axial vibration, and the output end of the transducer is connected to the horn; The amplitude changing rod is connected with the grinding wheel.

6. The ultrasonic assisted machining device for ceramic drilling according to claim 1, characterized in that: The machine tool body also includes a workbench for clamping workpieces, and the workbench is movable; The machine tool body also includes a cooling device for cooling.

7. A drilling method using the ultrasonic assisted machining device for ceramic drilling according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: clamping the workpiece to a preset position, starting the machine tool body and the ultrasonic generator, driving the ultrasonic tool holder to work, and driving the grinding wheel to drill the workpiece.

8. The drilling method according to claim 7, characterized in that: When drilling silicon nitride ceramic workpieces: The drilling method is direct drilling. The cutting depth is 0.005~0.01mm. Feed speed is not more than 100mm / min, The machine tool spindle speed shall not be less than 20000r / min.

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