CN108177030A - A kind of mirror grinding method of brait grinding wheel - Google Patents

Abstract

The invention discloses a method for mirror surface grinding of a rough diamond grinding wheel, which comprises the following steps: step 1: using an electrode dresser to discharge and trim the rough diamond grinding wheel; step 2: using the trimmed rough diamond grinding wheel The material surface adopts axial, small depth of cut and slow feed method for dry grinding; the feed depth is 1-20 microns, the diamond wheel speed is 1000-6000 rpm, and the feed speed is 5-200 mm/min ; Step three: Repeat step two until the mirror grinding effect is achieved. The invention can obtain a higher and more uniform grinding edge height, generate a larger chip space, facilitate the discharge of grinding heat, and improve the quality of the grinding surface; it has good wear resistance and effectively improves the grinding efficiency; Sharpening and dressing efficiency: adopt axial, small depth of cut and slow feed for dry grinding processing, cooperate with coarse diamond grinding wheel and electric discharge sharpening, the processing effect is good, and a good mirror grinding effect can be obtained.

Description

A kind of mirror surface grinding method of coarse diamond grinding wheel

technical field

The invention relates to the technical field of fine and precise manufacturing of superhard tools, in particular to a high-quality grinding process for hard and brittle materials, in particular to a mirror grinding method for rough diamond grinding wheels.

Background technique

Hard and brittle materials have high hardness, high melting point and high brittleness, and their physical and mechanical properties (especially toughness and strength) are very different from those of metal materials. In order to obtain high-quality hard and brittle material products, many industrially developed countries are currently devoting themselves to the processing research of hard and brittle materials.

High-performance hard and brittle materials such as optical devices, glass, and engineering ceramics are widely used. They have high hardness and low fracture toughness, which are difficult to process and difficult to obtain high-quality surfaces. Traditional dressing methods such as abrasive grinding method, diamond pen dressing method and grinding mild steel method not only have low dressing efficiency, but also have problems such as difficult control of shaping accuracy and complicated operation. In recent years, many new trimming technologies have emerged, such as laser trimming, electrochemical corrosion trimming, and online electrolytic trimming. Although the trimming accuracy has been improved, these processing methods have low efficiency, high production costs, and require difficult-to-handle corrosion solutions.

For hard and brittle materials, ultra-precision grinding wheel grinding technology is the most practical and effective processing method, which can obtain high processing accuracy and efficiency. However, the faster wear of finer-grain diamond grinding wheels and frequent sharpening and reconditioning have always been the technical bottleneck of industrialization. The problem to be solved urgently is how to delay the wear of ultra-precision grinding tools. The metal-based diamond grinding wheel tool can be used for mechanical forming processing of hard and brittle materials, with high processing efficiency and low cost. However, a diamond grinding wheel with coarser grains cannot obtain a high-quality machined surface, and the surface roughness of the machined workpiece is high.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a mirror grinding method for rough diamond grinding wheels processed by electric spark discharge sharpening, axial, small depth of cut and slow feed mode grinding, and to obtain mirror grinding effect .

The purpose of the present invention is achieved by the following technical solutions:

A kind of specular grinding method of rough diamond emery wheel, it comprises the steps:

Step 1: Discharge and sharpen the rough diamond grinding wheel with a hybrid electrode dresser, so that the surface of the rough diamond grinding wheel is sharpened and trimmed;

Step 2: Use the trimmed rough diamond grinding wheel to perform dry grinding on the surface of hard and brittle materials in an axial, small depth of cut and slow feed mode; the feed depth is 1-20 microns, and the diamond grinding wheel speed is 1000- 6000 rpm, feed speed is 5-200 mm/min;

Step 3: Repeat step 2 until the mirror grinding effect is achieved.

As a preferred manner, the diamond grinding wheel is a metal-based rough diamond grinding wheel.

As a preferred manner, the metal-based rough diamond grinding wheel is mainly composed of bronze bond and diamond abrasive, and the diamond abrasive has a particle size of 20-120 mesh.

As a preferred manner, the electrode of the hybrid electrode dresser adopts a planar electrode or a cap-shaped electrode, and the electrode material is a mixed electrode of cast iron and copper powder, and the mass percentage of cast iron and copper powder is 1:9~9:1.

As a preferred mode, the slow-feed mode of the small depth of cut is: the feed depth is 1-10 microns, the rotational speed of the diamond grinding wheel is 2000-5000 rpm, and the feed speed is 10-100 mm/min.

As a preferred manner, the step of carrying out discharge sharpening and trimming of the rough diamond grinding wheel is specifically to use electric spark discharge for sharpening and trimming, and use pulse electric spark discharge to remove the metal bond on the surface of the diamond grinding wheel, and at the same time use the mixed electrode The cast iron removes the top of the diamond abrasive grains, so that the surface of the grinding wheel is sharpened and trimmed by the abrasive grains.

As a preferred manner, the open circuit voltage of the pulse electric spark discharge is 10-200 volts, the current is 1-10 amperes, the pulse width is 1-200 microseconds, and the pulse interval is 1-200 microseconds.

Compared with prior art, the beneficial effect of the present invention is:

(1) Compared with the finer-grained diamond grinding wheel, the coarser-grained diamond grinding wheel can obtain a higher height of the abrasive grains, produce a larger chip space, and have a more consistent height of the abrasive grains, which is conducive to timely discharge of grinding Heat, improve the quality of the grinding surface, to achieve a mirror effect;

(2) Compared with the traditional fine-grain grinding wheel, the wear of the coarse-grain grinding wheel is slower, the grinding surface of the grinding wheel has better holding force and good wear resistance, which can effectively improve the grinding efficiency;

(3) Compared with the traditional mechanical sharpening, electric discharge sharpening can greatly improve the sharpening and dressing efficiency of coarse-grained grinding wheels, and at the same time, it can obtain larger and more uniform grinding edge heights, and less damage and damage to the grinding surface. crack;

(4) Adopt axial, small depth of cut and slow feed method for dry grinding, cooperate with coarse diamond grinding wheel and electric discharge sharpening, the processing effect is good, and a good mirror grinding effect can be obtained.

Description of drawings

Fig. 1 is a partially enlarged schematic diagram of the abrasive grains on the surface of the rough diamond grinding wheel after the conventional electric discharge sharpening.

Fig. 2 is a partially enlarged schematic diagram of abrasive grains emerging from the surface of a rough diamond grinding wheel after electric discharge sharpening and trimming according to an embodiment of the present invention.

Detailed ways

The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

A method for mirror surface grinding of a rough diamond emery wheel, comprising the steps of:

Step 1: The diamond grinding wheel is sharpened and trimmed by a hybrid electrode dresser, so that the surface of the rough diamond grinding wheel is sharpened and trimmed. The electrode of the electrode dresser adopts a flat electrode or a cap-shaped electrode;

Step 2: Use the sharpened diamond grinding wheel to perform dry grinding on the surface of hard and brittle materials in an axial, small depth-of-cut and slow-feed mode; the feed depth is 1-20 microns, and the diamond grinding wheel speed is 1000-6000 rev/min, the feed speed is 5-200 mm/min;

Step 3: Repeat step 2 until the mirror grinding effect is achieved.

In a preferred embodiment, the diamond grinding wheel is a metal-based rough diamond grinding wheel.

In a preferred embodiment, the metal-based rough diamond grinding wheel is composed of bronze bond and diamond abrasive, and the diamond abrasive has a particle size of 20-120 mesh.

In a preferred embodiment, the electrode of the hybrid electrode dresser adopts a planar electrode or a cap-shaped electrode, and the electrode material is a mixed electrode of cast iron and copper powder, and the mass percentage of cast iron and copper powder is 1:9~9: 1.

In a preferred embodiment, the small depth of cut and slow feeding method is as follows: the feeding depth is 1-10 microns, the rotational speed of the diamond grinding wheel is 2000-5000 rpm, and the feeding speed is 10-100 mm/min.

In a preferred embodiment, the step of performing electric discharge sharpening and dressing on the rough diamond grinding wheel is specifically to use electric spark discharge for sharpening and dressing, using pulse electric spark discharge to remove the metal bond on the surface of the diamond grinding wheel, and using a mixed electrode The cast iron removes the top of the diamond grit, so that the surface of the grinding wheel is sharpened and trimmed by the grit. Wherein, the open circuit voltage of the pulse electric spark discharge is 10-200 volts, the current is 1-10 amps, the pulse width is 1-200 microseconds, and the pulse interval is 1-200 microseconds. Fig. 1 is a partial enlarged schematic diagram of the abrasive grains on the surface of the rough diamond grinding wheel before discharge sharpening, and Fig. 2 is a partially enlarged schematic diagram of the abrasive grains on the surface of the rough diamond grinding wheel after electric discharge sharpening. Combining Fig. 1 and Fig. 2, it can be seen that, Compared with the existing electric discharge sharpening and dressing method, the coarser-grained diamond grinding wheel of this embodiment can obtain a higher abrasive particle edge height after electric discharge sharpening and trimming, produce a larger chip space, and the abrasive particle edge height It is more consistent and conducive to the timely discharge of grinding heat, thereby improving the quality of the grinding surface and achieving a mirror effect.

In a preferred embodiment, #46 bronze bond diamond grinding wheel is used, and the rough diamond grinding wheel is sharpened by contact discharge sharpening method, and the diamond grinding wheel after sharpening is used for axial dry grinding of cemented carbide (YG8) Processing test, the surface roughness Ra of the obtained cemented carbide can reach 73nm ~ 89nm.

Compared with traditional mechanical sharpening, electric discharge sharpening can obtain the largest and neatest abrasive grain exit height (see Figure 2), resulting in less grinding heat and surface roughness. The coarse diamond grinding wheel has a large abrasive grain edge height and rigidity, so it can obtain a smooth macroscopic grinding surface, and can realize precise mirror dry grinding of cemented carbide.

In a preferred embodiment, the experiment adopts 46# bronze bond diamond grinding wheel, adopts the above-mentioned contact discharge sharpening method to sharpen the rough diamond grinding wheel, and the diamond grinding wheel after sharpening is to three kinds of mold steels (8418, NAK80 and S136H) Conduct axial dry grinding test. Compared with mechanical sharpening, the diamond grinding wheel after electric discharge sharpening can obtain better surface quality. After grinding, the surface roughness Ra of the three mold steels reaches 0.022µm, 0.030µm and 0.027µm respectively. The surface can achieve a mirror effect. This is because after electric discharge sharpening, the coarse-grained diamond abrasive grains can reach a higher edge height of the abrasive grains, resulting in a larger chip space, which is also conducive to timely discharge of grinding heat. Therefore, the 46# coarse diamond grinding wheel with electric discharge repairing can realize the mirror dry grinding of mold steel, and its surface roughness Ra can reach as low as 0.022 μm.

In the above embodiments, the EDM sharpening method can be used for efficient and precise sharpening and dressing of coarse-grained metal-based diamond grinding wheels. Compared with traditional mechanical sharpening, it can greatly improve the grinding wheel sharpening efficiency and effectively increase the surface area of the grinding wheel. The edge height of the fine abrasive grains increases the number of effective abrasive grains, increases the chip space in the abrasive grain cutting area, reduces the accumulation of debris when the abrasive grains of the grinding wheel are removed from the workpiece, and obtains a mirror grinding effect.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. a method for mirror grinding of rough diamond emery wheel, is characterized in that, it comprises the steps: Step 1: Discharge and sharpen the rough diamond grinding wheel with a hybrid electrode dresser, so that the surface of the rough diamond grinding wheel is sharpened and trimmed; Step 2: Use the trimmed rough diamond grinding wheel to perform dry grinding on the surface of hard and brittle materials in an axial, small depth of cut and slow feed mode; the feed depth is 1-20 microns, and the diamond grinding wheel speed is 1000- 6000 rpm, feed speed is 5-200 mm/min; Step 3: Repeat step 2 until the mirror grinding effect is achieved. 2. The mirror surface grinding method of a rough diamond grinding wheel according to claim 1, characterized in that: said diamond grinding wheel is a metal base rough diamond grinding wheel. 3. the mirror surface grinding method of a kind of rough diamond grinding wheel according to claim 2, is characterized in that: described metal base rough diamond grinding wheel is mainly made up of bronze bond and diamond abrasive, and described diamond abrasive particle size is 20～ 120 mesh. 4. the mirror grinding method of a kind of rough diamond grinding wheel according to claim 1, is characterized in that: the electrode of described hybrid electrode dresser adopts planar electrode or cap electrode, and described electrode material is the mixture of cast iron and copper powder. For mixed electrodes, the mass percentage of cast iron and copper powder is 1:9~9:1. 5. The mirror surface grinding method of a kind of coarse diamond grinding wheel according to claim 1, characterized in that: the slow-feeding mode of the small depth of cut is: the feed depth is 1 to 10 microns, and the speed of the diamond grinding wheel The speed is 2000-5000 rpm, and the feed speed is 10-100 mm/min. 6. The mirror grinding method of a rough diamond grinding wheel according to any one of claims 1 to 3, characterized in that: the step of carrying out discharge sharpening and trimming of the rough diamond grinding wheel is specifically the use of electric spark discharge repairing Sharp trimming, using pulse electric spark discharge to remove the metal bond on the surface of the diamond grinding wheel, and at the same time using the cast iron with mixed electrodes to remove the top of the diamond abrasive grains, so that the grinding wheel surface is sharpened and trimmed. 7. The mirror surface grinding method of a rough diamond grinding wheel according to claim 6, characterized in that: the open circuit voltage of the pulse electric spark discharge is 10-200 volts, the current is 1-10 amps, and the pulse width is 1 ~ 200 microseconds, the pulse interval is 1 ~ 200 microseconds.