Ultrathin superhard composite material and processing method thereof

Abstract

The application provides a kind of ultra-thin superhard composite material and its processing method, using PCD / PCBN layer and hard alloy layer alternately multiple times processing, or simultaneous processing method, production and manufacture a kind of ultra-thin polycrystalline diamond / polycrystalline cubic boron nitride composite material.The interface of conventional ultra-thin polycrystalline diamond / polycrystalline cubic boron nitride composite material is combined with plane structure, polycrystalline diamond / polycrystalline cubic boron nitride layer is first processed to the required size, then hard alloy is processed to the required size.The ultra-thin PDC / PCBN composite material provided by the application has high processing precision, small internal stress and high yield.In particular, by alternately processing and grinding the upper and lower PCD / PCBN layer and hard alloy layer, the stress is always controlled at a small level to avoid the problem of fragmentation caused by high stress, and finally the ultra-thin superhard composite material with the required size thickness is realized.

Description

An ultrathin, ultrahard composite material and its processing method Technical Field

[0001] This invention relates to the field of superhard materials technology, specifically to a method for processing superhard composite materials, and more specifically to a method for processing ultrathin polycrystalline diamond / polycrystalline cubic boron nitride composite materials. Background Technology

[0002] Polycrystalline diamond composite (PDC) combines the hardness and wear resistance of diamond with the strength, impact toughness, and good weldability of cemented carbide, making it widely used in many machining fields. Polycrystalline cubic boron nitride (PCBN) composites, second only to polycrystalline diamond (PCD) in hardness and wear resistance, possess excellent chemical inertness, high thermal stability and high-temperature red hardness, high thermal conductivity, and a low coefficient of friction; they can be used for hard-cutting to achieve the final shaping of hardened parts. Tools made from PDC and PCBN have become the preferred choice for high-speed, high-efficiency, and precision machining.

[0003] Currently, the total thickness of commonly used PDC / PCBN composite materials ranges from 1.0-50mm, with a common thickness of 2.0-30mm. The total thickness of the PCD / PCBN layer is 0.5-4.0mm, with a common thickness of 0.5-3.0mm. In ultra-precision machining applications, such as the 3C industry (3D glass, ceramic and metal casings and frames), heat sinks, optical devices, and semiconductor devices, high precision is required for tool material processing. Thicker PDCs present machining difficulties, necessitating ultra-thin PDC / PCBN composite materials with a total thickness below 1.0mm and a PCD / PCBN layer thickness below 0.5mm. Simultaneously, the total thickness tolerance must be within ±0.05mm, the PCD / PCBN layer thickness within ±0.1mm, and the overall height difference <0.2mm. This is due to the difficulty in machining ultra-hard materials and the internal stress caused by the significant material property differences between the PCD / PCBN and the cemented carbide substrate. The difficulty in manufacturing ultrathin polycrystalline diamond / polycrystalline cubic boron nitride (PCD / PCBN) composite materials limits their large-scale application in ultra-precision machining. Therefore, there is an urgent need to develop a new PCD / PCBN processing method. Summary of the Invention

[0004] To address the problems existing in the aforementioned technologies, this invention provides a redesigned interface bonding shape between the PCD / PCBN layer and the cemented carbide layer in a PCD / PCBN composite material. This involves alternating or simultaneous processing of the PCD / PCBN layer and the cemented carbide layer to manufacture an ultrathin polycrystalline diamond / polycrystalline cubic boron nitride composite material. Conventional ultrathin polycrystalline diamond / polycrystalline cubic boron nitride composite materials have a planar interface bonding shape, requiring the polycrystalline diamond / polycrystalline cubic boron nitride layer to be processed to the required dimensions first, followed by the cemented carbide layer. However, due to the difficulty in processing ultrahard materials and the internal stress caused by the significant material property differences between the PCD / PCBN and the cemented carbide substrate, the arching increases as the total thickness decreases, reaching an arching greater than 0.3 mm, and even leading to overall fragmentation. The design of this invention overcomes this technical problem.

[0005] This invention provides a method for processing ultrathin and ultrahard composite materials, which includes the following steps:

[0006] Step 1: Obtain an ultrathin and ultrahard composite material. The ultrathin and ultrahard composite material has a PCD / PCBN layer and a cemented carbide layer. The interface of the cemented carbide layer is concave.

[0007] Step 2: Machining the carbide layer to a depth of C1. At this point, due to the release of internal stress, the upper surface of the PCD / PCBN layer will arch up to a height of P1.

[0008] Step 3: Machin the upper surface of the PCD / PCBN layer, with a grinding depth of P1, and re-machine the upper surface of the PCD / PCBN layer into a planar shape;

[0009] Step 4: Machining the carbide layer to a depth of C2. At this point, due to the release of internal stress, the upper surface of the PCD / PCBN layer will arch up to a height of P2.

[0010] Repeat steps 3 and 4 until step n-1, the PPCD / PCBN layer thickness is adjusted to the required thickness, and the interface between the PCD / PCBN layer and the cemented carbide layer is parallel.

[0011] Step n: Finally, the carbide layer is machined and ground to the required total thickness, completing the machining process.

[0012] Preferably, in step 1, the PCD / PCBN composite superhard material layer is bonded to the cemented carbide layer by a high temperature and high pressure method;

[0013] The recess depth of the cemented carbide layer is P0; the center of the PCD / PCBN layer is P0 thicker than the edge.

[0014] Preferably, the cemented carbide layer and the PCD / PCBN layer are processed by machining, electrical discharge machining, or laser processing.

[0015] Preferably, the cemented carbide layer and the PCD / PCBN layer are machined simultaneously on both sides.

[0016] The ultrathin and ultrahard composite material prepared by this invention has a total thickness of h = 0.3 mm, with an error within h ± 0.1 mm; and a total thickness of H = 0.8 mm, with an error of H ± 0.05 mm.

[0017] The ultra-thin PDC / PCBN composite material provided by this invention has high processing precision, low internal stress, and high yield.

[0018] Specifically, this invention achieves ultra-thin and ultra-hard composite materials with the required thickness by alternating grinding of the upper and lower PCD / PCBN layers and cemented carbide layers, thereby keeping the stress at a low level and avoiding breakage caused by high stress. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the ultrathin PCD / PCBN composite material of the present invention;

[0020] Figure 2. Schematic diagram of ultrathin PCD / PCBN composite material processed by conventional processing methods;

[0021] Figure 3 shows the process diagram of the ultrathin PCD / PCBN composite material processing method of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to Figures 1-3. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0023] Figure 1 is a schematic diagram of the ultrathin PCD / PCBN composite material of the present invention. 101 is the PCD / PCBN (polycrystalline diamond / polycrystalline cubic boron nitride) layer, and 102 is the cemented carbide matrix. 101 and 102 are bonded together by high temperature and high pressure. Its dimensions are: total thickness H < 1.0 mm, H ± 0.05 mm; total thickness h of the PCD / PCBN layer < 0.5 mm, h ± 0.1 mm; and overall arching (the difference between the high and low points on the upper surface of the PCD / PCBN layer) < 0.2 mm.

[0024] Figure 2 is a schematic diagram of an ultrathin PCD / PCBN composite material processed using conventional methods. 201 represents the arched structure formed when a conventional ultrathin PCD / PCBN layer is bonded to the cemented carbide layer (202). Due to the difficulty in processing ultrahard materials and the internal stress caused by the significant difference in material properties between the PCD / PCBN and the cemented carbide substrate, the arching degree increases as the total thickness decreases, eventually exceeding 0.3 mm, and even leading to overall fragmentation.

[0025] Figure 3 is a process diagram of the ultrathin PCD / PCBN composite material processing method of the present invention. Step 1: The PCD / PCBN composite superhard material is prepared using existing equipment and high-pressure chambers commonly used for synthesizing PCD / PCBN composite superhard materials. The material has a PCD / PCBN layer and a cemented carbide layer. For example, the high-temperature and high-pressure process used has a pressure of 5-15 GPa and a temperature of 1200-2500℃.

[0026] As shown in the figure of step 1, the blank (ultra-thin PCD / PCBN composite material) has a concave shape at the cemented carbide interface with a depth of P0; the center of the PCD / PCBN layer is thicker than the edge by P0, so the upper surface of the PCD / PCBN layer is a planar structure and the lower surface of the PCD / PCBN layer is embedded in the concave shape of the cemented carbide interface.

[0027] Step 2: Machining the carbide layer using methods such as mechanical processing, electrical discharge machining, or laser processing, with a grinding depth of C1. At this point, due to the release of internal stress, the upper surface of the PCD / PCBN layer will arch up to a height of P1.

[0028] Step 3: The upper surface of the PCD / PCBN layer is processed by mechanical processing, electrical discharge machining, laser processing, etc., with a grinding depth of P1. The upper surface of the PCD / PCBN layer is reprocessed into a planar shape.

[0029] Step 4: Machining the carbide layer using methods such as machining, electrical discharge machining, and laser processing, with a grinding depth of C2. At this point, due to the release of internal stress, the upper surface of the PCD / PCBN layer will arch up to a height of P2.

[0030] Repeat steps three and four;

[0031] Until the (n-1)th step, the PCD / PCBN layer thickness reaches the required thickness, and the PCD / PCBN layer is parallel to the cemented carbide interface;

[0032] Step n: Finally, the carbide layer is processed by machining, electrical discharge machining, laser machining, etc., and ground to the required total thickness, thus completing the processing.

[0033] Example 1

[0034] Step 1: Prepare PCD / PCBN composite superhard materials using existing equipment and high-pressure chambers commonly used for synthesizing PCD / PCBN composite superhard materials. The materials have a PCD / PCBN layer and a cemented carbide layer. Preferably, the pressure in the high-temperature and high-pressure process is 5-15 GPa and the temperature is 1200-2500℃.

[0035] Prepare a blank (PCD / PCBN composite superhard material) as shown in Figure 1. The cemented carbide interface is concave, with a depth of P0; the PCD / PCBN layer is also thicker at the center than at the edge, with a thickness of P0 = 0.3 mm, and the edge thickness is 0.3 mm. The total thickness is H = 6.0 mm, and the final dimensions require a total thickness of H = 0.8 mm, H ± 0.05 mm; the total thickness of the PCD / PCBN layer is h = 0.3 mm, h ± 0.1 mm or less, and the overall arch (difference between the high and low points on the upper surface of the PCD / PCBN layer) is < 0.2 mm.

[0036] Step 2: Use a diamond wheel surface grinder to process the carbide layer. The grinding depth is C1 = 2mm. At this time, due to the release of internal stress, the arch height of the upper surface of the PCD / PCBN layer is P1 = 0.15mm.

[0037] Step 3: The upper surface of the PCD / PCBN layer is processed by mechanical processing, electrical discharge machining, laser processing, etc. The grinding depth is P1 = 0.1mm, and the upper surface of the PCD / PCBN layer is reprocessed into a planar shape.

[0038] Step 4: Use a diamond wheel surface grinder to process the carbide layer to a depth of C2 = 3mm. At this time, due to the release of internal stress, the arch height of the upper surface of the PCD / PCBN layer is P2 = 0.1mm.

[0039] Step 5: Machining the upper surface of the PCD / PCBN layer using methods such as machining, electrical discharge machining, and laser processing, with a grinding depth of P1 = 0.1 mm, and remachining the upper surface of the PCD / PCBN layer into a planar shape;

[0040] Step 6: Use a diamond wheel surface grinder to process the carbide layer to a depth of C2 = 2.2 mm. At this point, due to the release of internal stress, the arch height P2 of the upper surface of the PCD / PCBN layer is 0.1 mm.

[0041] Step 7: The upper surface of the PCD / PCBN layer is processed to a thickness of 0.3mm using machining, electrical discharge machining, laser processing, etc. The PCD / PCBN layer is parallel to the cemented carbide interface.

[0042] Step 8: Finally, use a diamond wheel surface grinder to process the carbide layer to the required total thickness of 0.8mm, and the processing is complete.

[0043] The ultra-thin PDC / PCBN composite material provided by this invention has high processing precision, low internal stress, and high yield.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A method for processing ultrathin, ultrahard composite materials, characterized in that, The process includes the following steps: Step 1: Obtain an ultrathin, ultrahard composite material. This material has a PCD / PCBN layer and a cemented carbide layer, with the interface of the cemented carbide layer being concave. Step 2: Machining the cemented carbide layer to a depth of C1. Due to the release of internal stress, the upper surface of the PCD / PCBN layer arches up to a height P1. Step 3: Machining the upper surface of the PCD / PCBN layer to a depth of P1, remachining the upper surface of the PCD / PCBN layer into a planar shape. Step 4: Machining the cemented carbide layer to a depth of C2. Due to the release of internal stress... Place the PCD / PCBN layer, raising the upper surface of the PCD / PCBN layer to a height P2; repeat steps 3 and 4; until step n-1, the PCD / PCBN layer thickness reaches the required thickness, and the interface between the PCD / PCBN layer and the cemented carbide layer is parallel; in step n, finally process the cemented carbide layer, grinding it to the required total thickness, and the processing is completed; by alternately processing and grinding the upper and lower PCD / PCBN layers and the cemented carbide layer, the stress is always controlled at a small level to avoid the problem of breakage caused by high stress, and finally the ultra-thin and ultra-hard composite material with the required thickness is realized.

2. The processing method of the ultrathin and ultrahard composite material according to claim 1, characterized in that, In step 1, the PCD / PCBN composite superhard material layer is bonded to the cemented carbide layer by high temperature and high pressure; the recess depth of the cemented carbide layer is P0; the center of the PCD / PCBN layer is P0 thicker than the edge.

3. The processing method of the ultrathin and ultrahard composite material according to claim 1, characterized in that, The cemented carbide layer and PCD / PCBN layer are processed by machining, electrical discharge machining, or laser.

4. The processing method of the ultrathin and ultrahard composite material according to claim 1, characterized in that, The cemented carbide layer and the PCD / PCBN layer are machined using a double-sided simultaneous machining method.

5. The ultrathin and ultrahard composite material prepared by the processing method of any one of claims 1-4, wherein the total thickness of the PCD / PCBN layer in the ultrathin and ultrahard composite material is h = 0.3 mm, with an error within h ± 0.1 mm; and the total thickness of the ultrathin and ultrahard composite material is H = 0.8 mm, with an error of H ± 0.05 mm.

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