WO2019237910A1

WO2019237910A1 - Rough-and-fine integrated progressive grinding method for non-slewing optical array

Info

Publication number: WO2019237910A1
Application number: PCT/CN2019/088551
Authority: WO
Inventors: 姚鹏; 张振中; 黄传真; 朱家豪; 王军; 朱洪涛; 刘含莲; 邹斌
Original assignee: 山东大学
Priority date: 2018-06-12
Filing date: 2019-05-27
Publication date: 2019-12-19
Also published as: CN108747603A; CN108747603B

Abstract

A rough-and-fine integrated progressive grinding method for a non-slewing optical array, comprising step 1: respectively designing and manufacturing structural outlines of a precisely structured rough grinding diamond grinding wheel (2-1) and a precisely structured ultrafine diamond grinding wheel (2-2) and a structure of a partition plate (10); step 2: sequentially mounting the precisely structured rough grinding diamond grinding wheel (2-1), the partition plate (10) and the precisely structured ultrafine diamond grinding wheel (2-2) in step 1 on a machine tool spindle; fixing a machining workpiece (11) on a machine tool table; step 3: dressing the grinding wheels in place; step 4: performing rough copying grinding: using a copying grinding method to perform rough grinding by means of the precisely structured rough grinding diamond grinding wheel (2-1); and step 5: performing progressive fine grinding on the basis of a tangent trajectory: along the progressive grinding trajectory, using the precisely structured ultrafine diamond grinding wheel (2-2) to perform progressive grinding on the workpiece surface, and through a grinding cycle, efficiently completing semi-fine machining and fine machining on the surface outline of the entire microstructure array.

Description

Coarse-fine integrated progressive grinding method for non-rotating optical array

Technical field

The invention relates to a grinding method of a non-rotating optical array, and in particular relates to a coarse and fine integrated progressive grinding method of a non-rotating optical array.

Background technique

Non-rotating optical arrays are a type of microstructured surface. Compared with other microstructures, they have a more complex surface structure. They are often used as key components in modern optics and communications. Non-rotating optical array optical elements can greatly simplify the system. The processing accuracy of non-rotating optical arrays is often high. The cell spacing of the array structure is generally at the millimeter or micron level. The surface accuracy and surface roughness requirements are at the sub-micron level and the nano-level, respectively. Compared with traditional rotary optics, The accuracy of array and non-rotating optical array parts is more difficult to guarantee. However, since ultra-precision grinding is currently the most effective method for precision machining of non-rotating optical array surfaces, its main implementation form is ultra-precision grinding using micro-abrasive tools on ultra-precision machine tools. However, the main problem is that the diamond grinding wheel and the workpiece are in single point contact. When the feed step is as low as a few micrometers, the machining efficiency is very low; the tip of the fine grinding wheel wears quickly, and the grinding wheel needs to be inserted multiple times to meet the shape accuracy requirements. Cycle, greatly reducing processing efficiency.

Summary of the Invention

The purpose of the present invention is to solve the problems of low single-point contact grinding efficiency and fast contour tip wear of traditional single-piece grinding wheels, and to propose a coarse and fine integrated progressive grinding method for non-rotating optical arrays. The present invention integrates semi-finishing and finishing, and can process non-rotating optical arrays with high shape accuracy on the surface of the workpiece. Non-rotating optical arrays can be represented as V-groove arrays, micro-circular groove arrays, micro-pyramid arrays, etc. , Can be used for ceramics, glass, hard alloy and other hard and brittle materials.

In order to achieve the above object, the present invention adopts the following technical solutions:

A coarse and fine integrated progressive grinding method for a non-rotating optical array includes the following steps:

Step 1 Coarse and fine integrated grinding wheel design and dressing: design and repair the structure outline of precision structured rough grinding diamond grinding wheel, precision structured ultra-fine diamond grinding wheel and the structure of partition plate respectively:

Step 2 Fixing and installation of the grinding wheel and the workpiece: Install the precision structured rough-ground diamond grinding wheel, the partition plate, and the precision structured ultra-fine diamond grinding wheel in step 1 on the machine tool's spindle in turn; fix the machining workpiece on the machine tool table ;

Step 3 Grinding wheel in-situ dressing: The contact or non-contact dressing method is used to precisely dress the contours of the structure arrays of the two types of grinding wheels to ensure the fixed position relationship between the rough and fine grinding wheels and the fine structure on the surface;

Step 4 Copy rough grinding: Use copy grinding method, rough grinding with precision structured rough grinding diamond grinding wheel, remove most of the volume of the workpiece, and reduce the grinding allowance of precision structured fine-grained or ultra-fine-grained diamond grinding wheel. , To reduce the wear of the grinding wheel, so as to ensure the final precision grinding accuracy.

Step 5 Progressive precision of tangent trajectory: follow the progressive grinding trajectory, that is, the trajectory of trajectory that is maintained tangent to the final contour of the workpiece according to the last microstructure unit of the grinding wheel, using a precision structured fine-grained or ultra-fine-grained diamond wheel The workpiece surface is progressively ground, and the semi-finishing and finishing of the entire microstructure array surface profile are efficiently completed through a grinding cycle.

Further, the contours of each structural unit of the precision structured coarse-grained diamond grinding wheel for contour rough grinding designed in step 1 are consistent, and the contour of the microstructure unit of the grinding wheel is designed according to the selected precision grinding allowance; precision grinding of tangent trajectory Fine-grained or ultra-fine-grained microstructure diamond grinding wheels need to design multiple highly graduated grinding wheel microstructure unit contours according to the precision grinding allowance and precision cutting depth; the thickness of the partition plate should be greater than that of the microstructure array workpiece. The width of the grinding wheel in the axial direction.

Further, the dressing device for the precision structured rough-ground diamond grinding wheel and the precision structured ultra-fine diamond grinding wheel described in step 1 includes a bracket, a Z-axis feeding mechanism, a nozzle, a friction wheel, and a control system; wherein, the The bracket is mounted on the grinding wheel cover, the Z-axis feeding mechanism is mounted on the bracket, and the nozzle is driven by the Z-axis feeding mechanism; the friction wheel is mounted on the lower side of the grinding wheel and the stepping motor drives the friction wheel to rotate; The control system is connected to a Z-axis feed mechanism and a stepping motor.

Further, the Z-axis feeding mechanism includes a linear motor for feeding a water jet nozzle along a surface of a grinding wheel.

Further, the processing method of the precision structured rough-ground diamond grinding wheel and the precision structured ultra-fine diamond grinding wheel described in step 1, adjusting the abrasive water jet nozzle so that the jet beam is radially perpendicular to the working surface of the diamond wheel, and by controlling the dressing device, The relative movement between the jet beam and the grinding wheel is realized, and the contour of the grinding wheel microstructure unit is processed on the surface of the grinding wheel.

Further, the grinding wheel is a two-size grinding wheel designed for semi-finishing and finishing.

Further, the contour of the grinding wheel array unit and the contour of the workpiece contour have no overcuts.

Further, the outline of the workpiece array is V-shaped, curved or other shapes.

The beneficial technical effects of the present invention are as follows:

(1) The microstructure processing of the grinding wheel surface by the abrasive water jet solves the problem that the dressing tools of the mechanical dressing method are easy to wear, and the laser and the micro-EDM dressing method cause thermal damage to the surface of the grinding wheel. The height of the abrasive particles on the surface of the grinding wheel is large, and there is no wear on the dressing tool.

(2) By actively controlling the relative movement of the nozzle and the surface of the grinding wheel, it is possible to achieve the creation of a variety of microstructures on the surface of the grinding wheel, improve the grinding performance of the grinding wheel, improve the quality of the surface and subsurface of the workpiece, and improve the grinding accuracy.

(3) The grinding wheel rotates at a constant speed and the dwell time of the nozzle movement can be precisely controlled. The precise cross-section profile shape of the fine structure array on the surface of the grinding wheel can be actively controlled. This type of precision grinding wheel array structure can be used to realize precision parts with periodic array structure (such as gears and High-precision contour grinding of the surface of an optical part with an array structure).

(4) The in-situ grinding wheel dressing method adopted in the present invention can avoid customizing super-hard abrasive grinding wheels with complex shapes, greatly reducing the cost of processing tools; can quickly respond to the processing requirements of various complex curved surface arrays, and greatly shorten the development cycle of new products.

(5) The present invention breaks through the traditional non-rotating optical array processing steps, uses two integrated grinding wheels with different particle sizes as processing tools, and uses hard, brittle and difficult-to-machine materials as processing objects. This grinding method reduces the wear of the precision structured ultra-fine diamond grinding wheel of the grinding wheel and improves the machining accuracy. The integrated grinding wheel and the coarse and fine integrated grinding method are used to double the number of grinding processing cycles required for array processing. It avoids the tool changing time and re-setting operation required to replace the coarse and fine-grained grinding wheels in different procedures, reduces the number of grinding wheel dressings, and can greatly improve the processing efficiency. It can be used for ceramics, glass, hard alloy and other hard and brittle materials. The invention solves to a certain extent a series of problems such as low efficiency of non-rotating optical array grinding, frequent replacement of grinding wheels, etc., and realizes efficient and high-quality grinding processing of non-rotating optical array based on precision structured grinding wheels.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings that form a part of the present application are used to provide further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

FIG. 1 is a schematic diagram of an abrasive water jet dressing device with a profile of a grinding wheel array;

Figure 2 is a schematic diagram of the abrasive water jet dressing principle of the profile of the grinding wheel array;

Figure 3 is a diagram of various fine structures on the surface of the grinding wheel and the mutual movement relationship between the corresponding grinding wheel and the workpiece;

FIG. 4 is an outline profile of the grinding wheel array after the abrasive water jet is trimmed in a specific embodiment; FIG.

5 and 6 are schematic diagrams of rough grinding stages of a non-rotating optical array according to the present invention;

Figure 7 is a partial enlarged view A of the precision structured ultra-fine diamond grinding wheel of Figure 6;

FIG. 8 is a partial enlarged view B of the precision structured rough-ground diamond grinding wheel of FIG. 6.

FIG. 9 is a schematic diagram of a refining stage of a non-rotating optical array according to the present invention.

In the picture: 1 grinding wheel cover; 2 grinding wheels; 3 bracket; 4 nozzles; 5 Z-axis feed mechanism; 6 linear motors; 7 stepping motors; 8 rubber friction wheels; 9 jet beams; 2-1 precision structured rough-ground diamond Grinding wheels; 2-2 precision structured ultra-fine diamond grinding wheels; 10 partition plates; 11 workpieces; 12 lateral grinding trajectories; A partial enlarged view of A precision structured ultra-fine diamond grinding wheels; B partial enlarged view of precision structured rough-ground diamond grinding wheels .

detailed description

It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used herein is only for describing specific embodiments and is not intended to limit the exemplary embodiments according to the present application. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should also be understood that when the terms "including" and / or "including" are used in this specification, they indicate The presence of features, steps, operations, devices, components and / or combinations thereof;

For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, it only means that it is consistent with the up, down, left, and right directions of the drawing itself, and does not limit the structure. It is for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

Term explanation: The terms "installation", "connection", "connection", and "fixation" in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or a whole; It is a mechanical connection, it can be an electrical connection, it can be a direct connection, or it can be indirectly connected through an intermediate medium. It can be an internal connection of two elements, or an interaction relationship between two elements. For those of ordinary skill in the art, The specific meanings of the above terms in the present invention can be understood according to specific situations.

As described in the background technology, in the prior art, ultra-precision grinding is currently the most effective method for precision machining of the surface of non-rotating optical arrays, and its main implementation form is the use of micro-grinding tools for ultra-precision grinding on ultra-precision machine tools. Cutting. However, the main problem is that the diamond grinding wheel and the workpiece are in single point contact. When the feed step is as low as a few micrometers, the machining efficiency is very low; the tip of the fine grinding wheel wears quickly, and the grinding wheel needs to be inserted multiple times to meet the shape accuracy requirements. Cycle, which greatly reduces the processing efficiency. In order to solve the above technical problems, this application proposes a coarse and fine integrated progressive grinding method for a non-rotating optical array. The specific method is as follows:

Step 1 Design and repair the microstructure contour of the grinding wheel: the contour of each structural unit of the precision structured coarse-grained diamond grinding wheel used for contour rough grinding is consistent, and the contour of the microstructure unit of the grinding wheel is designed according to the selected precision grinding allowance; The fine-grained or ultra-fine-grained microstructure diamond grinding wheels for grinding need to design multiple highly graduated grinding wheel microstructure unit contours according to the precision grinding allowance and precision grinding cutting depth. The thickness of the partition plate 10 should be greater than the width of the microstructure array workpiece in the axial direction of the grinding wheel.

At present, the surface structuring methods of the grinding wheel mainly include two categories: the orderly arrangement of millimeter or micron-scale abrasive particles on the surface of the grinding wheel by CVD, electroplating or brazing; and the use of mechanical, laser, and micro-EDM grinding wheel dressing methods. A micro or macro groove array structure is machined on the surface of the grinding wheel. The latter can obtain the grinding wheel surface structure with higher accuracy. However, the common disadvantages of grinding wheel dressing methods such as machinery, lasers, and micro-EDM are that the dressing device is complex, the dressing tools wear quickly, the dressing efficiency is low, and the dressing costs are high. For example, the turning method uses diamond pens as a dressing tool for dressing super-hard abrasive wheels. This method is only suitable for dressing super-abrasive wheels of ceramic binders, and the dressing tools wear quickly and the dressing efficiency is low; laser and micro-EDM dressing methods The dressing accuracy is high, but the abrasive grains on the surface are carbonized due to high temperature, and the surface abrasive grains will wear quickly; the fine structure of the metal bonded diamond grinding wheel lacks an efficient and precise dressing method; the precision structured rough grinding diamond grinding wheel of the present invention 2- 1 and precision structured ultra-fine diamond grinding wheel 2-2 The array profile adopts the abrasive water jet dressing method, using the abrasive water jet dressing device of the grinding wheel array profile as shown in Figures 1 and 2, which includes the grinding wheel cover 1, the grinding wheel 2. Bracket 3 mounted on the wheel cover, abrasive water jet nozzle 4, Z-axis feed mechanism 5, linear motor 6, stepper motor 7; rubber friction wheel 8;

Among them, the Z-axis feed mechanism includes a linear motor 6, a bracket 3; the Z-axis feed mechanism is installed on the right side of the grinding wheel cover 1, and the nozzle 4 is installed on the lower side of the Z-axis feed mechanism. The control system and the Z-axis feed mechanism connection.

The bracket 3 is fixed on the grinding wheel cover by screws to complete the positioning, and the Z-axis feeding mechanism can complete the Z-axis feeding movement to complete the control of the relative movement between the nozzle and the surface of the grinding wheel.

Under the control of the rubber friction wheel 8, the grinding wheel 2 rotates at a constant speed or intermittently at a certain time interval. The nozzle 4 is continuously or intermittently reciprocated in the Z-axis direction under the control of the stepper motor 7 to obtain the relative movement of the nozzle and the surface of the grinding wheel. Abrasive water jet processing is used to achieve precise processing of various fine structures on the surface of the grinding wheel to improve the grinding performance and improve the grinding quality.

The grinding wheel rotates at a constant speed and the dwell time of the nozzle movement can be precisely controlled. The precise cross-section profile shape of the fine structure array on the surface of the grinding wheel can be actively controlled. This type of precision grinding wheel array structure can be used to implement precision parts with periodic array structure (such as gears and array structures). High-precision contour grinding of the surface of optical parts.

The manufacturing method of the specific grinding wheel array contour is realized by the following steps:

As shown in Figures 3 and 4, the abrasive water jet nozzle 4 is adjusted so that the jet beam 9 is perpendicular to the working surface of the diamond wheel. By controlling the uniform rotation of the wheel and precisely controlling the residence time of the nozzle movement, the fine structure cross-section profile of the wheel surface can be achieved. Active precision control for efficient and precise machining of precise microstructure arrays;

Step 2. As shown in Fig. 5 and Fig. 6, fix the processing workpiece 11 on the machine tool table, the highly structured precision structured rough-ground diamond grinding wheel 2-1, and the highly graduated microstructure designed according to the grinding allowance. The fine diamond grinding wheel 2-2 is installed on the machine tool spindle; in order to prevent the precision structured ultra-fine diamond grinding wheel from colliding with the workpiece 11 during the grinding of the precision structured rough grinding diamond grinding wheel, a partition plate 10 is used to separate the two grinding wheels. open.

Step 3. In the rough grinding stage, the precision structured grinding wheel uses a metal bonding diamond grinding wheel, and the precision structured rough grinding diamond grinding wheel 2-1 has a particle size of # 60 ～ # 600; the grinding wheel is mounted on the spindle, and the spindle rotates at a high speed, and the workpiece follows the grinding machine. The workbench reciprocates, the spindle of the grinding wheel descends and gradually cuts into the workpiece. The cut-in grinding path 12 is used, and the finely structured rough-grinding diamond grinding wheel 2-1 is used to profile the surface of the workpiece 11. The 5 main grooves of the grinding wheel are retracted when the designed finishing allowance is reached. The diamond grinding wheel feeds at a depth of 5-50 μm each time, and the cumulative feed depth is 100-1000 μm.

Step 4. In the fine grinding stage, the granularity of the precision structured ultrafine diamond grinding wheel 2-2 is # 1500 ～ # 5000; the surface of the workpiece 4 is ground by using the precision structured ultrafine diamond grinding wheel 2. In the fine grinding stage Ⅰ, the fine structural unit at the front end of the precision structured ultra-fine diamond grinding wheel 2-2 is gradually cut into the workpiece 11, and along the movement tangent to the contour of the workpiece, it is removed layer by layer based on the grooves that are profiled and ground. Reserved grinding allowance; fine grinding stage Ⅱ, the final fine structural unit of the precision structured ultra-fine diamond grinding wheel 2-2 cuts the final grinding allowance along the tangent trajectory to complete a contour cycle of the non-rotating optical array ; Fine grinding stage III, precision structured ultra-fine diamond grinding wheel 2-2 is cut out from the workpiece 11, the contour of each microstructure unit of the workpiece is consistent. Through a grinding cycle, semi-finishing and finishing of the entire microstructure array surface profile are efficiently completed.

The parameters of the metal-bonded diamond grinding wheel are: a diameter of 200mm, a width of 1-16mm, and a concentration of 70 to 200%.

The rotation speed of the grinding wheel: the linear speed of the outer circle when the grinding wheel rotates, is 5m / s to 30m / s; the feeding speed of the table: 100mm / min to 20000mm / min; the number of polishing times: 3 to 4 times.

The contour of the grinding wheel array unit and the bottom of the workpiece contour are not overcut.

The surface shape accuracy and surface roughness of the surface of the non-rotating optical array can reach sub-micron level and nano-level, respectively.

Although the specific embodiments of the present invention are described above with reference to the accompanying drawings, the scope of protection of the invention is not limited. Those skilled in the art should understand that based on the technical solution of the present invention, those skilled in the art do not need to innovate. Various modifications or deformations that can be made through labor are still within the protection scope of the present invention.

Claims

A coarse and fine integrated progressive grinding method for a non-rotating optical array is characterized in that it includes the following steps:

Step 1 Design and trim the structure outline of the precision structured rough-ground diamond grinding wheel, the precision structured ultra-fine diamond grinding wheel, and the structure of the partition plate, respectively:

Step 2 sequentially install the precision structured rough-ground diamond grinding wheel, the partition plate and the precision structured ultra-fine diamond grinding wheel in step 1 on the machine tool spindle; fix the processing workpiece on the machine tool workbench;

Step 3 Grinding wheel in-situ dressing: The contact or non-contact dressing method is used to precisely dress the contours of the structure arrays of the two types of grinding wheels to ensure the fixed position relationship between the rough and fine grinding wheels and the fine structure on the surface;

Step 4 Copy rough grinding: Use copy grinding, rough grinding with a precision structured rough grinding diamond wheel, to remove most of the volume of the workpiece;

Step 5 Progressive precision of tangent trajectory: follow the progressive grinding trajectory, that is, the trajectory of trajectory that is maintained tangent to the final contour of the workpiece according to the last microstructure unit of the grinding wheel, using a precision structured fine-grained or ultra-fine-grained diamond wheel The workpiece surface is progressively ground, and the semi-finishing and finishing of the entire microstructure array surface profile are efficiently completed through a grinding cycle.
The coarse and fine integrated progressive grinding method for a non-rotating optical array according to claim 1, characterized in that the contours of each structural unit of the precision structured coarse-grained diamond grinding wheel for contour rough grinding designed in step 1 are consistent According to the selected precision grinding allowance, design the contour of the grinding wheel microstructure unit; the fine-grained or ultra-fine-grained fine-structure diamond grinding wheel for tangential trajectory precision grinding needs to design multiple according to the precision grinding allowance and the precision grinding cutting depth Highly graded grinding wheel microstructure element outline; the thickness of the partition plate should be greater than the width of the microstructure array workpiece in the axial direction of the grinding wheel.
The coarse and fine integrated progressive grinding method for a non-rotating optical array according to claim 1, characterized in that, the dressing device of the precision structured rough grinding diamond grinding wheel and the precision structured ultra-fine diamond grinding wheel described in step 1: It includes a bracket, a Z-axis feeding mechanism, a nozzle, a friction wheel, and a control system; wherein the bracket is mounted on a grinding wheel cover, the Z-axis feeding mechanism is mounted on a bracket, and the nozzle is controlled by a Z-axis feeding mechanism Driven; the friction wheel is mounted on the lower side of the grinding wheel, and the friction wheel is driven by a stepping motor to rotate; the control system is connected to a Z-axis feed mechanism and a stepping motor.
The method of claim 3, wherein the Z-axis feed mechanism comprises a linear motor for feeding a water jet nozzle along a surface of a grinding wheel.
The coarse and fine integrated progressive grinding method for a non-rotating optical array according to claim 3, characterized in that, the processing method of the precision structured rough grinding diamond grinding wheel and the precision structured ultra-fine diamond grinding wheel described in step 1, The abrasive water jet nozzle is adjusted so that the jet beam is radially perpendicular to the working surface of the diamond wheel. By controlling the dressing device, the relative movement of the jet beam and the wheel is realized, and the contour of the microstructure unit of the wheel is processed on the surface of the wheel.
The coarse and fine integrated progressive grinding method for a non-rotating optical array according to claim 1, wherein the contour of the grinding wheel microstructure unit and the bottom of the workpiece contour are free from overcutting.
The method of claim 1, wherein the outline of the workpiece array is V-shaped, curved or other shapes.