WO2020232791A1

WO2020232791A1 - Combined electric spark grinding machining tool, tool manufacturing method and machining method

Info

Publication number: WO2020232791A1
Application number: PCT/CN2019/092567
Authority: WO
Inventors: 伍晓宇; 雷建国; 鲁艳军; 徐斌; 翁昌兴; 谢晋; 汤勇
Original assignee: 深圳大学
Priority date: 2019-05-21
Filing date: 2019-06-24
Publication date: 2020-11-26
Also published as: CN112351862B; CN112351862A; CN211331681U

Abstract

Provided is a combined electric spark grinding machining tool, comprising a grinding wheel matrix (1), grinding sections (5), and electrode sections (2). The grinding wheel matrix (1) is of a disc shape, the grinding sections (5) and the electrode sections (2) are alternately arranged on an end face of an outer edge of the grinding wheel matrix (1), and by arranging a grinding wheel tool with the electrode sections (2) and the grinding sections (5) alternately arranged, rough machining and finishing machining of super-hard and difficult-to-grind materials can be completed within a one-time clamping range. Further provided are a manufacturing method for the combined electric spark grinding machining tool and a combined electric spark grinding machining method.

Description

Electric spark grinding composite processing tool, tool preparation method and processing method

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on May 21, 2019, with application number 2019207527108, and the title of the invention "a kind of electric spark grinding composite machining tool", the entire content of which is incorporated herein by reference Applying.

Technical field

This application relates to the technical field of grinding processing tools, and in particular to an electric spark grinding composite processing tool, a tool preparation method and a processing method.

Background technique

The processing technology of superhard and hard-to-grind materials is an important field in advanced materials and advanced manufacturing technology. It is widely used in many industrial sectors of the aerospace industry, mold industry, automobile manufacturing and various special-purpose products. The processing of difficult-to-grind materials, low processing efficiency and high tool wear are traditional problems, which often require multiple rough/finish machining and multiple clamping and positioning, the process is cumbersome, and the machining error is difficult to control.

EDM composite machining technology is an effective means to improve the processing efficiency of superhard and difficult-to-grind materials with electrical conductivity, and through the effective combination of EDM and abrasive cutting, high-quality machined surfaces can be obtained . However, most metal-based adhesives are not ideal tool electrode materials. In the rough machining stage, it is difficult to achieve high-energy EDM removal for large-depth machining, the abrasive particles fall off quickly, and the grinding wheel wears quickly.

technical problem

The main purpose of this application is to provide an EDM grinding composite machining tool, its preparation and its machining method, aiming to set up a grinding wheel tool with a high-performance electrode segment and a grinding segment alternately distributed within one clamping range Technical problems of high-efficiency rough machining and high-quality finishing of super-hard and difficult-to-grind materials.

Technical solutions

In order to achieve the purpose of the above application, this application proposes an EDM grinding composite machining tool, which includes a grinding wheel base, a grinding section and an electrode section. The grinding wheel base is in the shape of a disc, and the grinding section and the electrode section alternate It is arranged on the outer edge end surface of the grinding wheel base body.

The grinding section is formed by uniformly mixing abrasive grains and a metal-based adhesive and then sintering, and the EDM loss rate of the electrode section is less than the EDM loss rate of the metal-based EDM of the grinding section.

The metal-based adhesive is made of copper, tin mixed powder and or copper-tin alloy powder.

A preparation method of electric spark grinding composite machining tool includes the steps:

The grinding wheel base is processed on the base material of preset thickness;

Putting the grinding wheel base into a first mold and filling it with a first preset material for sintering, to obtain a grinding wheel base containing electrode segments;

The grinding wheel base body containing the electrode segments is put into a second mold and filled with a second preset material for sintering to obtain a first grinding wheel.

The step of processing a grinding wheel matrix on a substrate with a predetermined thickness includes:

The grinding wheel base is machined on stainless steel, brass or easy-turning iron with a thickness of 0.5mm-20mm.

The step of putting the grinding wheel matrix into a first mold and filling the first preset material for sintering to obtain a grinding wheel matrix containing electrode segments includes:

The grinding wheel matrix is put into a first mold and filled with pure copper powder, pure tungsten powder, brass powder or cupronickel powder for sintering to obtain a grinding wheel matrix containing electrode segments.

The step of putting the grinding wheel base body containing the electrode segments into a second mold and filling with a second preset material for sintering to obtain the first grinding wheel includes:

The grinding wheel matrix containing the electrode segments is put into a second mold and filled with a mixture of a metal-based binder and an abrasive for sintering to obtain a first grinding wheel.

An electric spark grinding composite machining method proposed in this application includes the steps:

Install the first grinding wheel and the workpiece on the grinding machine respectively, the first grinding wheel is connected to the negative pole of the pulse power supply, and the workpiece is connected to the positive pole of the pulse power supply;

Adjust the first grinding wheel to a first height; use high-energy discharge process parameters to rough machine the workpiece;

Adjust the first grinding wheel to a second height; use low-energy discharge process parameters to finish machining the workpiece to obtain a workpiece with a high-quality machining surface.

The process parameters of the high-energy discharge refer to a processing voltage of 90-120V and a pulse width of 10-50 μs.

The process parameters of the low-energy discharge refer to a processing voltage of 30-50V and a pulse width of 1-10μs.

Beneficial effect

An EDM grinding composite machining tool, preparation and machining method provided in this application, by arranging a grinding wheel tool with a high-performance electrode segment and a grinding segment distributed alternately, the super hard and difficult can be completed within a single clamping range High efficiency rough machining and high quality finishing of grinding materials.

Description of the drawings

FIG. 1 is a schematic diagram of the structure of an electric spark grinding composite machining tool according to an embodiment of the present application;

Figure 2 is a schematic diagram of EDM composite rough machining in another embodiment of the present application;

Fig. 3 is a schematic diagram of EDM composite finishing in another embodiment of the present application.

The best mode of the invention

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of this application are only used to explain the difference between components in a specific posture (as shown in the accompanying drawings). If the relative positional relationship, movement situation, etc. change, the directional indication changes accordingly. The connection may be a direct connection or an indirect connection.

In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on what can be achieved by a person of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist. , Not within the scope of protection required by this application.

As shown in Figures 1-3, a preferred embodiment of the present application is proposed as an EDM composite machining tool, which includes a grinding wheel base 1, a grinding section 5 and an electrode section 2. The grinding wheel base 1 is disc-shaped and is ground The segments 5 and the electrode segments 2 are alternately arranged on the outer edge end surface of the grinding wheel base 1. In this embodiment, the EDM loss rate of electrode section 2 is less than the metal-based EDM loss rate of grinding section 5, which can prevent abrasive particles 3 from falling off quickly during the composite rough machining stage of EDM grinding, and improve the super hard and hard-to-wear The efficiency of rough machining of cutting materials. In the finishing process, the low-energy electric spark discharge gap δ2 is smaller than the height of the abrasive particles 3, which can improve the surface quality of the finishing workpiece 6 made of super-hard and difficult-to-grind materials.

In this embodiment, the arc lengths of the grinding section 5 and the electrode section 2 are equal, and the grinding section 5 is formed by mixing and sintering abrasive particles 3 and a metal-based adhesive. The electrode section 2 is sintered from electrode material powder, and the EDM loss rate of the electrode material should be less than the EDM loss rate of the metal base 4. The workpiece 6 is rough-machined using the process parameters that form the high-energy discharge, so that the high-energy EDM discharge gap δ1 is greater than or equal to the height h of the abrasive grains. The EDM loss rate of electrode section 2 is slightly lower than that of grinding section 5 metal base 4 EDM, so the diameter of electrode section 2 is slightly larger than the diameter of the metal base 4 of grinding section 5, reaching electrode section 2 to grinding section 5 The protective effect prevents the abrasive particles 3 from falling off quickly. In other embodiments, the arc length of the grinding section and the electrode section can be adjusted.

The grinding wheel base body 1 is made of stainless steel, brass or easy-turning iron. In this embodiment, the material of the grinding wheel substrate 1 includes stainless steel, brass, and free-turning iron. The free-turning iron is free-cutting steel. The metal machinability is enhanced by adding elements such as sulfur or lead, and the machine tool cutting performance is good. The outer diameter of the grinding wheel base 1 ranges from 40 mm to 200 mm, the inner diameter of the grinding wheel base 1 ranges from 12 mm to 35 mm, and the thickness of the grinding wheel base 1 ranges from 0.5 mm to 20 mm.

The electrode section 2 is made of pure copper powder, pure tungsten powder, brass powder or cupronickel powder. Copper has high electrical conductivity, thermal conductivity, abrasion resistance and excellent process performance, with a particle size range of 1μm~20μm.

The abrasive particles 3 are made of diamond particles, boron carbide particles or silicon carbide abrasive materials. Diamond, boron carbide and silicon carbide have the characteristics of low density, high strength, high temperature stability and good chemical stability, and the particle size ranges from 0.1μm to 10μm.

The metal binder is made of copper, tin mixed powder and or copper-tin alloy powder. The particle size range of copper and tin mixed powder is 1μm-20μm, and the particle size range of copper-tin alloy powder is 25μm-50μm.

In this embodiment, the grinding section 5 and the electrode section 2 need to be respectively sintered to the circumference of the grinding wheel base 1 and alternately connected to form a grinding wheel tool. The arc length of the grinding section 5 and the electrode section 2 can be adjusted. The grinding section 5 is made by uniformly mixing the metal-based adhesive and abrasive particles and then sintered; the electrode section 2 is made by sintering the electrode material powder, and the EDM loss rate of the electrode material should be less than that of the metal-based adhesive. Processing loss rate.

Specific embodiment 1:

In this specific embodiment, an EDM grinding composite machining tool, the EDM grinding composite machining tool has an annular array form, and the grinding wheel tool is composed of an electrode section 2 and a grinding section 5 composed of high-performance electrode materials. Distribution composition. The grinding wheel base 1 in this embodiment is disc-shaped, and the grinding section 5 and the electrode section 2 are alternately arranged on the outer edge end surface of the grinding wheel base 1. The grinding section 5 is formed by mixing and sintering abrasive particles 3 and a metal-based binder , The EDM loss rate of the electrode section 2 is less than that of the metal base 4. Put the grinding wheel base 1 into the first mold and fill the blank of the outer circle with copper powder for sintering to obtain a ring-shaped array electrode section 2 Grinding wheel base body; then put the grinding wheel base body containing the annular array electrode segment 2 into the second mold, fill the mixed powder of copper powder, tin powder and diamond abrasive in the blank of the outer circle, and perform sintering again to obtain the electrode segment 2 and the grinding wheel. The cutting segments 5 are alternately connected to form a complete grinding wheel of the outer circle of the grinding wheel tool. With this special grinding wheel tool, high-efficiency rough machining and high-quality finishing of super-hard and difficult-to-grind materials can be completed within a clamping range. During rough machining, use process parameters that can form high-energy discharge, so that the high-energy EDM discharge gap δ1 is greater than the height h of the abrasive grain, to achieve high-efficiency and high-energy EDM rotary machining, and the grinding wheel grinding section 5 completes the edge; When using process parameters that can form a low-energy discharge, the low-energy EDM discharge gap δ2 is less than or equal to the height of the abrasive grain h, and high-precision EDM rotary machining is realized.

Specific embodiment 2:

In this specific embodiment, an EDM grinding composite machining tool, the EDM grinding composite machining tool has an annular array form, and the grinding wheel tool is composed of an electrode section 2 and a grinding section 5 composed of high-performance electrode materials. Distribution composition. The grinding wheel base 1 in this embodiment is disc-shaped. The grinding section 5 and the electrode section 2 are alternately arranged on the outer edge end surface of the grinding wheel base 1. The grinding section 5 is made by mixing abrasive particles 3 and a metal-based binder. The EDM loss rate of the electrode section 2 is less than the loss rate of the metal base 4 of the grinding section 5. The electrode section in this embodiment is mixed and sintered with copper, tin mixed powder and copper-tin alloy powder, and then contains the ring array electrode The grinding wheel matrix of section 2 is placed in the second mold, and the mixed powder of boron carbide granules and copper-tin alloy powder is filled in the outer circle. In this embodiment, the grinding wheel matrix 1 is processed on a 20mm thick free-wheeling iron. The special grinding wheel tool can complete the high-efficiency rough machining and high-quality finishing of super-hard and difficult-to-grind materials within a single clamping range. During rough machining, use process parameters that can form high-energy discharge, so that the high-energy EDM discharge gap δ1 is greater than the height h of the abrasive grain, to achieve high-efficiency and high-energy EDM rotary machining, and the grinding wheel grinding section 5 completes the edge; When using process parameters that can form a low-energy discharge, the low-energy EDM discharge gap δ2 is less than or equal to the height of the abrasive grain h, and high-precision EDM rotary machining is realized.

Specific embodiment 3:

This embodiment proposes a method for preparing an EDM grinding composite machining tool based on the above specific embodiment 1, including the steps:

The grinding wheel base 1 is processed on a stainless steel plate with a thickness of 15mm by using the wire EDM process; stainless steel has strong wear resistance.

Put the grinding wheel base 1 into the first mold and fill with copper powder for sintering to obtain the grinding wheel base 1 containing the electrode segment 2;

Put the grinding wheel base 1 containing the electrode segment 2 into the second mold and fill it with copper, tin mixed powder and diamond abrasive grains, and then sinter it to obtain the complete outer circle of the grinding wheel tool containing electrode segments 2 and grinding segments 5 alternately connected Grinding wheel.

Specific embodiment 4:

This embodiment is based on the method for preparing an EDM grinding composite machining tool proposed in the foregoing specific embodiment 2, and includes the steps:

The grinding wheel base 1 is machined on the easy-turning iron with a thickness of 10mm by using the electric discharge wire cutting process; the easy-turning iron has strong wear resistance.

The grinding wheel base 1 is put into the first mold and filled with pure tungsten powder for sintering to obtain the grinding wheel base 1 containing the electrode segment 2.

Put the grinding wheel base body 1 containing the electrode segment 2 into the second mold and fill it with boron carbide granules and copper-tin alloy powder, and then sinter it to obtain the second electrode segment 2 and the grinding segment 5 alternately connected to form the outer circle of the grinding wheel tool One grinding wheel.

As shown in Figures 3-5, a preferred embodiment of the present application is proposed as an EDM composite machining method, including the steps:

Install the first grinding wheel and the workpiece 6 on the grinding machine respectively, the first grinding wheel is connected to the negative pole of the pulse power supply, and the workpiece 6 is connected to the positive pole of the pulse power supply;

In this embodiment, the material of the workpiece 6 is titanium alloy, hard alloy, silicon carbide or conductive ceramic.

Adjust the first grinding wheel to the first height. The first height in this embodiment refers to setting the high-energy electric spark discharge gap to δ1; using the high-energy discharge process parameters to perform rough machining on the workpiece 6; making the electrode segment 2 discharge The gap δ1 is greater than or equal to the height h of the abrasive grain exiting edge, which realizes high-efficiency and high-energy EDM rotary machining, and the grinding wheel grinding section 5 completes the edge extraction. The EDM loss rate of electrode section 2 is less than the metal base EDM loss rate of grinding section 5, so that the diameter of electrode section 2 is greater than the metal base diameter of grinding section 5. After that, electrode section 2 protects the grinding section 5 and prevents The abrasive particles 3 fall off quickly.

Adjust the first grinding wheel to the second height. The second height in this embodiment refers to setting the low-energy electric spark discharge gap to δ2; use the low-energy discharge process parameters to finish machining the workpiece 6 so that the electrode segment 2 discharges The gap is less than or equal to the height h of the abrasive grain exiting edge, which realizes high-precision electric discharge grinding and rotation processing, and obtains a workpiece 6 with a high-quality processing surface.

In this embodiment, the process parameters of high-energy discharge refer to a processing voltage of 90-120V and a pulse width of 10-50 μs; the process parameters of low-energy discharge refer to a processing voltage of 30-50 V and a pulse width of 1-10 μs.

Using this special grinding wheel tool, high-efficiency roughing and high-quality finishing of super-hard and difficult-to-grind materials can be completed within a single clamping range. During rough machining, use process parameters that can form high-energy discharge, so that the high-energy EDM discharge gap δ1 is greater than the height h of the abrasive grain, to achieve high-efficiency and high-energy EDM rotary machining, and the grinding wheel grinding section 5 completes the edge; When using process parameters that can form a low-energy discharge, the low-energy EDM discharge gap δ2 is less than or equal to the height of the abrasive grain h, and high-precision EDM rotary machining is realized.

Specific embodiment 5:

This embodiment is based on the electric spark grinding composite machining method proposed in the above specific embodiment 1, and includes the steps:

The first grinding wheel and the workpiece 6 are respectively installed on the grinder, the first grinding wheel is connected to the negative electrode of the pulse power supply, and the workpiece 6 is connected to the positive electrode of the pulse power supply; the material of the workpiece 6 in this embodiment is conductive ceramic.

Adjust the first grinding wheel to the first height required for the rough machining depth; use high-energy discharge process parameters to rough-machine the workpiece 6; make the high-energy EDM discharge gap δ1 greater than or equal to the height of the abrasive grain h, achieving high efficiency and high energy At the same time, the grinding wheel grinding section 5 completes the cutting edge. The EDM loss rate of electrode section 2 is less than the metal base EDM loss rate of grinding section 5, so that the diameter of electrode section 2 is greater than the metal base diameter of grinding section 5. After that, electrode section 2 protects the grinding section 5 and prevents The abrasive particles 3 fall off quickly.

Adjust the first grinding wheel to the second height required for the finishing depth; use the low-energy discharge process parameters to finish the workpiece 6 so that the low-energy electric spark discharge gap δ2 is less than or equal to the height of the abrasive grain h, achieving high precision Electric spark grinding and rotating processing, to obtain high-quality work piece 6.

In this embodiment, the process parameters of high-energy discharge refer to a processing voltage of 120V and a pulse width of 50 μs; the process parameters of low-energy discharge refer to a processing voltage of 50 V and a pulse width of 10 μs.

Specific embodiment 6:

This embodiment is based on the above-mentioned specific embodiment 2 and proposed an electric spark grinding composite machining method, including the steps:

The first grinding wheel and the workpiece 6 are respectively installed on the grinding machine, the first grinding wheel is connected to the negative electrode of the pulse power supply, and the workpiece 6 is connected to the positive electrode of the pulse power supply; the material of the workpiece 6 in this embodiment is silicon carbide. Silicon carbide, also known as emery, is made by smelting raw materials such as quartz sand, petroleum coke (or coal coke), wood chips (salt is needed to produce green silicon carbide) through a high temperature resistance furnace. Silicon carbide is also a rare mineral in nature. Silicon carbide is also called moissanite. Among the non-oxide high-tech refractory raw materials such as C, N, and B, silicon carbide is the most widely used and most economical one, and it can be called gold steel grit or refractory grit. Silicon carbide has stable chemical properties, high thermal conductivity, low thermal expansion coefficient and good wear resistance.

In this embodiment, the process parameters of high energy discharge refer to a processing voltage of 100V and a pulse width of 40 μs; the process parameters of low energy discharge refer to a processing voltage of 40 V and a pulse width of 5 μs.

The electric spark grinding composite machining tool of the present application can complete high-efficiency rough machining and high-quality finishing of super-hard and difficult-to-grind materials within a clamping range. During rough machining, use process parameters that can form high-energy discharge, so that the high-energy EDM discharge gap δ1 is greater than the height h of the abrasive grain, to achieve high-efficiency and high-energy EDM rotary machining, and the grinding section of the grinding wheel completes the edge; , Using process parameters that can form low-energy discharge, make the low-energy EDM discharge gap δ2 less than or equal to the height of the abrasive grains, h, and realize high-precision EDM rotary machining. In this embodiment, an electric spark grinding composite machining tool, preparation and machining method thereof, by setting a high-performance electrode segment and a grinding wheel tool distributed alternately with the grinding segment, can complete the super-hard and difficult High efficiency rough machining and high quality finishing of grinding materials.

Claims

An electric spark grinding composite machining tool, which is characterized by comprising a grinding wheel base, a grinding section and an electrode section, the grinding wheel base is in the shape of a disc, and the grinding section and the electrode section are alternately arranged on the grinding wheel The outer edge of the base.
The EDM composite machining tool according to claim 1, wherein the grinding section is formed by uniformly mixing abrasive particles and a metal-based adhesive and then sintered, and the EDM loss rate of the electrode section is less than The EDM loss rate of the metal base of the grinding section.
The electric spark grinding composite machining tool according to claim 2, wherein the metal-based adhesive is made of copper, tin mixed powder, or copper-tin alloy powder.
A preparation method of an electric spark grinding composite machining tool is characterized in that it comprises the following steps:

The grinding wheel base is processed on the base material of preset thickness;

Putting the grinding wheel base into a first mold and filling it with a first preset material for sintering, to obtain a grinding wheel base containing electrode segments;

The grinding wheel base body containing the electrode segments is put into a second mold and filled with a second preset material for sintering to obtain a first grinding wheel.
The method for preparing an EDM grinding composite machining tool according to claim 4, wherein the step of processing a grinding wheel matrix on a substrate with a predetermined thickness comprises:

The grinding wheel matrix is processed on stainless steel, brass or easy-turning iron with a thickness of 0.5mm-20mm.
The method for preparing an EDM composite machining tool according to claim 4, wherein the grinding wheel matrix is put into a first mold and filled with a first preset material for sintering to obtain a grinding wheel containing electrode segments The steps of the matrix include:

The grinding wheel matrix is put into a first mold and filled with pure copper powder, pure tungsten powder, brass powder or cupronickel powder for sintering to obtain a grinding wheel matrix containing electrode segments.
The method for preparing an EDM composite machining tool according to claim 4, wherein the grinding wheel matrix containing the electrode segments is placed in a second mold and filled with a second preset material for sintering to obtain the first The steps of a grinding wheel include:

The grinding wheel base body containing the electrode segments is put into a second mold and filled with a mixture of a metal-based binder and an abrasive for sintering to obtain a first grinding wheel.
An electric spark grinding compound machining method, which is characterized in that it comprises:

Install the first grinding wheel and the workpiece on the grinding machine respectively, the first grinding wheel is connected to the negative pole of the pulse power supply, and the workpiece is connected to the positive pole of the pulse power supply;

Adjust the first grinding wheel to a first height; use high-energy discharge process parameters to rough machine the workpiece;

Adjust the first grinding wheel to a second height; use low-energy discharge process parameters to finish machining the workpiece to obtain a workpiece with a high-quality machining surface.
The EDM composite machining method according to claim 8, wherein the process parameters of the high-energy discharge are a machining voltage of 90-120V and a pulse width of 10-50μs.
The EDM composite machining method according to claim 8, wherein the process parameters of the low-energy discharge are a machining voltage of 30-50V and a pulse width of 1-10μs.