Diamond lathe tool center height adjusting device and adjusting method

Abstract

The invention relates to the technical field of ultra-precision machining, in particular to a device and method for adjusting the center height of a diamond lathe tool, and the device is characterized in that a pneumatic conversion clamp is installed on a stand column of an ultra-precision machine tool; the image acquisition module is arranged on the pneumatic conversion clamp; the piezoelectric ceramic lifting platform is installed on the ultra-precision machine tool, and the ultra-precision machine tool controls the piezoelectric ceramic lifting platform to move in the X direction and the Z direction. The diamond cutter is mounted on the piezoelectric ceramic lifting platform; the piezoelectric controller controls the piezoelectric ceramic lifting platform to move and step length in the Y direction; and the upper computer is respectively connected with the image acquisition module and the piezoelectric controller. The center height of the diamond cutter is fed back through image definition, and on-machine automatic adjustment is achieved. According to the method, image feedback and cutter motion control are combined, rough and fine cutter image definition climbing method adjustment is adopted, full-automatic sequential center height automatic adjustment of multiple cutters is achieved, the detection process is executed in a non-contact mode, and good measurement consistency and stability are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-precision machining, and in particular relates to a device and method for adjusting the center height of a diamond lathe tool. Background Art

[0002] Diamond ultra-precision turning machines, as a key component of ultra-precision machining, are widely used in the ultra-high-precision manufacturing of optical components, semiconductor components, and small aerospace parts. Diamond cutting tools, as key machine tool components, achieve extremely high surface profile accuracy and quality during ultra-precision machining due to their extremely high hardness, excellent mechanical properties, and chemical stability.

[0003] During ultra-precision machining, the process requires multiple diamond tools to be exchanged for machining. Before machining, the tip height of the diamond turning tool must be verified to facilitate process programming. Currently, the center height of diamond lathe tools is adjusted manually by adjusting the differential thread in the tool holder. Feedback is provided by a contact-type capacitive sensor to determine whether the diamond tool tip of the diamond lathe is flush. This method has low adjustment efficiency, and the adjustment accuracy depends on the accuracy of the capacitive sensor. The adjustment device is expensive, and the tool tip status cannot be directly observed.

[0004] The Chinese invention patent publication number is CN202011269485.6, and the publication date is February 2, 2021. The patent name is a macro-micro composite diamond turning tool height adjustment tool holder based on piezoelectric ceramics. The macro-micro motion of piezoelectric ceramics replaces the traditional manual adjustment method of the differential thread in the tool holder. However, it is still necessary to determine the center height of the diamond lathe tool through trial cutting iteration, and the tool tip state cannot be directly observed. The center height adjustment of multiple diamond tools still has the problems of high cost and low adjustment efficiency. Therefore, the proposal of a non-contact rapid adjustment device and method for the center height of diamond lathe tools has important engineering significance and practical value. Summary of the Invention

[0005] In view of this, the present invention aims to provide a diamond lathe tool center height adjustment device and adjustment method to solve the problems of low adjustment efficiency and precision and high cost of the adjustment device in the prior art.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: A diamond lathe tool center height adjustment device, comprising: a pneumatic conversion fixture, an image acquisition module, a piezoelectric ceramic lifting platform, a piezoelectric controller, a diamond tool and a host computer; The pneumatic conversion fixture is installed on the column of the ultra-precision machine tool; the image acquisition module is arranged on the pneumatic conversion fixture; the piezoelectric ceramic lifting platform is installed on the ultra-precision machine tool, and the ultra-precision machine tool controls the piezoelectric ceramic lifting platform to move along the X direction and the Z direction; the diamond tool is installed on the piezoelectric ceramic lifting platform; the piezoelectric controller controls the movement and step length of the piezoelectric ceramic lifting platform along the Y direction; the host computer is connected to the image acquisition module and the piezoelectric controller respectively.

[0007] Furthermore, it also includes an adapter plate; the image acquisition module is arranged on the pneumatic conversion fixture through the adapter plate.

[0008] Furthermore, the image acquisition module includes: a camera, a coaxial microscope tube, an imaging objective lens and a coaxial light source; the coaxial microscope tube is fixed on the adapter plate, the camera is arranged at one end of the coaxial microscope tube, the imaging objective lens is arranged at the other end of the coaxial microscope tube, and the coaxial light source is installed on the coaxial microscope tube.

[0009] Furthermore, it also includes a lens barrel clamp; the coaxial microscope barrel is fixed on the adapter plate through the lens barrel clamp.

[0010] Furthermore, it also includes a light source controller; the light source controller controls the brightness and wavelength of the coaxial light source.

[0011] Furthermore, it also includes a tool fixture; the diamond tool is installed on the piezoelectric ceramic lifting platform through the tool fixture.

[0012] A method for adjusting a tool center height adjustment device of a diamond lathe, the method comprising the following steps: The ultra-precision machine tool controls the piezoelectric ceramic lifting platform to move along the X direction and the Z direction so that the diamond tool is imaged at the mirror point of the imaging object; The host computer controls the camera to turn on, and controls the light source controller to adjust the brightness of the coaxial light source; Setting the coarse adjustment movement step length, coarse adjustment speed, fine adjustment movement step length and fine adjustment speed of the piezoelectric ceramic lifting platform; The host computer controls the piezoelectric controller to move the piezoelectric ceramic lifting platform along the Y direction according to the coarse adjustment movement step and coarse adjustment speed; at the same time, each movement step of the piezoelectric ceramic lifting platform triggers the host computer to capture the image of the diamond tool through the camera; The host computer calculates the clarity of the diamond tool image and controls the piezoelectric ceramic lifting platform to move repeatedly until the maximum value of the clarity of the diamond tool image is obtained; Stopping the movement of the piezoelectric ceramic lifting platform and extracting the edge of the diamond tool image; Performing primitive segmentation on the edge of the diamond tool image to obtain the primary and secondary cutting edge edges and the tool tip arc edge of the diamond tool respectively; Performing linear fitting on the primary and secondary cutting edges to obtain an intersection position, and setting the intersection position as a tool tip position; Performing circle fitting on the arc edge of the tool tip, obtaining a circumscribed rectangle of the fitted circle, and setting it as a diamond tool ROI image; The host computer controls the piezoelectric controller to move the piezoelectric ceramic lifting platform along the Z direction according to the fine adjustment movement step and fine adjustment speed; at the same time, each movement step of the piezoelectric ceramic lifting platform triggers the host computer to capture the diamond tool ROI image through the camera; The host computer calculates the clarity of the diamond tool ROI image and controls the piezoelectric ceramic lifting platform to move repeatedly until the maximum value of the diamond tool ROI image clarity is obtained, thereby realizing a method for adjusting the center height of a diamond lathe tool.

[0013] Compared with the prior art, the present invention can achieve the following beneficial effects: A device and method for adjusting the center height of diamond lathe tools utilizes image clarity feedback to achieve on-machine automatic adjustment. Combining image feedback with Y-direction tool motion control, this method utilizes a hill-climbing method for tool image clarity during roughing and fine adjustments to achieve fully automatic, sequential center height adjustment of multiple tools. The non-contact detection process offers superior measurement consistency and stability compared to traditional capacitive contact detection or manual trial cutting adjustments. Diamond tool center height adjustment can be achieved entirely through image clarity detection feedback, providing technical support for ensuring ultra-precision turning accuracy with diamond tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 This is a functional block diagram of a diamond lathe tool center height adjustment device according to an embodiment of the present invention; Figure 2 This is a flow chart of a method for adjusting the center height of a diamond lathe tool according to an embodiment of the present invention; Figure 3 This is a clarity calculation diagram of a diamond lathe tool center height adjustment method described in an embodiment of the present invention.

[0015] Explanation of the accompanying symbols: 1. Pneumatic conversion fixture, 2. Adapter plate, 3. Camera, 4. Coaxial microscope tube, 5. Imaging objective lens, 6. Coaxial light source, 7. Tube fixture, 8. Piezoelectric ceramic lifting platform, 9. Piezoelectric controller, 10. Light source controller, 11. Diamond tool, 12. Tool fixture, 13. Host computer. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar elements in different embodiments use associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present invention are not shown or described in the specification. This is to avoid the core part of the present invention being overwhelmed by too much description. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0017] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various orders in the description and the drawings are only for the purpose of clearly describing a certain embodiment and are not intended to be a required order, unless otherwise specified that a certain order must be followed.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0019] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0020] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0021] like Figure 1 As shown, a diamond lathe tool center height adjustment device includes: a pneumatic conversion fixture 1, an adapter plate 2, a camera 3, a coaxial microscope tube 4, an imaging objective lens 5, a coaxial light source 6, a tube fixture 7, a piezoelectric ceramic lifting platform 8, a piezoelectric controller 9, a light source controller 10, a diamond tool 11, a tool fixture 12 and a host computer 13.

[0022] The pneumatic conversion fixture 1 is mounted on the column of the ultra-precision machine tool. In this embodiment, the pneumatic conversion fixture 1 adopts a pneumatic clamping method with a repeatability of 1 μm and a payload of 10 kg. The adapter plate 2 is set on the pneumatic conversion fixture 1.

[0023] The coaxial microscope tube 4 is fixed to the adapter plate 2 via a tube fixture 7. The camera 3 is disposed at one end of the coaxial microscope tube 4, the imaging objective lens 5 is disposed at the other end of the coaxial microscope tube 4, and the coaxial light source 6 is coaxially mounted on the coaxial microscope tube 4. The light source controller 10 controls the brightness and wavelength of the coaxial light source 6.

[0024] In this embodiment, camera 3 is a black-and-white area array CMOS sensor with an imaging resolution of 2448×2048 and a pixel size of 3.45 μm. It connects to host computer 13 via a network interface. The coaxial microscope tube 4 utilizes an infinite conjugate optical path, and the imaging objective lens 5 has an M26 interface. The imaging objective lens 5 is an infinite long working distance plan achromatic objective lens with a magnification of 20x, a depth of field of 1.6 μm, a working distance of 20 mm, and an imaging field of view of 1.2 mm. The coaxial light source 6 is a high-brightness white LED light source with a power of 10 W.

[0025] A piezoelectric ceramic lift platform 8 is mounted on an ultra-precision machine tool, which controls its movement in the X and Z directions. In this embodiment, the piezoelectric lift platform 8 is piezoelectrically driven, with a minimum displacement of 0.01 μm. A piezoelectric controller 9 controls the activation and step size of the piezoelectric lift platform 8. A diamond tool 11 is mounted on the piezoelectric ceramic lift platform 8 via a tool holder 12 and moves in the Y direction. In this embodiment, the diamond tool 11 is a single-point diamond arc-edge turning tool with a tip radius of 0.2 mm. A host computer 13 is connected to the camera 3, the light source controller 10, and the piezoelectric controller 9.

[0026] like Figure 2 As shown, a method for adjusting the center height of a diamond lathe tool comprises the following steps: The ultra-precision machine tool controls the piezoelectric ceramic lifting platform to move along the X direction and the Z direction, so that the diamond tool 11 is imaged at the image point of the imaging objective lens 5.

[0027] The host computer 13 controls the camera 3 to turn on, and controls the light source controller 10 to adjust the brightness of the coaxial light source 6 so that the image of the diamond tool 11 is properly exposed.

[0028] Set the coarse adjustment step, coarse adjustment speed, fine adjustment step and fine adjustment speed of the piezoelectric ceramic lifting platform 8; in this embodiment, the coarse adjustment step is 10μm, the coarse adjustment speed is 100μm / s, the fine adjustment step is 0.01μm, and the fine adjustment speed is 1μm / s.

[0029] The coarse adjustment process is as follows: the host computer 13 controls the piezoelectric controller 9 to move the piezoelectric ceramic lifting platform 8 along the Y direction according to the coarse adjustment movement step and coarse adjustment speed; at the same time, each movement step of the piezoelectric ceramic lifting platform 8 triggers the host computer 13 to collect the image of the diamond tool 11 through the camera 3; the image width and height N×M size is 2448×2048.

[0030] The host computer 13 uses the image clarity evaluation method of the normalized image gradient sum to calculate the clarity of the diamond tool 11 image, controls the piezoelectric ceramic lifting platform 8 to move repeatedly through the piezoelectric controller 9, and uses the hill climbing optimization algorithm to obtain the maximum value of the diamond tool 11 image clarity; Figure 3As shown in the horizontal and vertical coordinates, the clarity s of the collected image at each step is calculated as follows:

[0031] in M and N Respectively represent the width and height of the diamond tool 11 image, G i and G j The Sobel horizontal gradient value and vertical gradient value of the image collected by the diamond tool 11 are respectively.

[0032] The movement of the piezoelectric ceramic lifting platform 8 is stopped, and the clearest image edge of the diamond tool 11 is extracted through image binarization and Sobel edge operator.

[0033] The fine-tuning process is as follows: a polygonal approximation algorithm is used to perform primitive segmentation of the edge image of the diamond tool 11 , and the primary and secondary cutting edge edges and the tool tip arc edge of the diamond tool 11 are obtained respectively.

[0034] The intersection position is obtained by linear fitting of the main and secondary cutting edges, and the intersection position is set as the tool tip position.

[0035] Perform least squares circle fitting on the edge of the tool tip arc, obtain the radius of the fitted circle, take the tool tip position as the center, and the radius of the fitted circle as the radius to establish the tool tip position circumscribed rectangle. Automatically set the tool tip circumscribed rectangle to the ROI image of the diamond tool 11, and the image width and height are M roi ×N roi .

[0036] The host computer 13 controls the piezoelectric controller 9 to move the piezoelectric ceramic lifting platform 8 along the Y direction according to the fine adjustment movement step and fine adjustment speed; at the same time, each movement step of the piezoelectric ceramic lifting platform 8 triggers the host computer 13 to collect the ROI image of the diamond tool 11 through the camera 3.

[0037] The ROI image is subjected to Sobel gradient processing and gradient sorting. The upper computer 13 uses the sum of the first K gradients after sorting to calculate the clarity of the ROI image of the diamond tool 11, controls the piezoelectric ceramic lifting platform 8 to move repeatedly, and uses the hill climbing optimization algorithm to obtain the maximum value of the ROI image clarity of the diamond tool 11, thereby realizing a method for adjusting the center height of the diamond lathe tool.

[0038] The clarity of the sum of the first K gradients is calculated as follows:

[0039] in G a and G bThe first K The Sobel horizontal and vertical gradient values ​​of the pixel location, K is generally set to 10.

[0040] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0041] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A diamond lathe tool center height adjustment device, characterized by: The device includes: a pneumatic conversion fixture, an image acquisition module, a piezoelectric ceramic lifting platform, a piezoelectric controller, a diamond tool and a host computer; The pneumatic conversion fixture is installed on the column of the ultra-precision machine tool; the image acquisition module is arranged on the pneumatic conversion fixture; the piezoelectric ceramic lifting platform is installed on the ultra-precision machine tool, and the ultra-precision machine tool controls the piezoelectric ceramic lifting platform to move along the X direction and the Z direction; the diamond tool is installed on the piezoelectric ceramic lifting platform; the piezoelectric controller controls the movement and step length of the piezoelectric ceramic lifting platform along the Y direction; the host computer is connected to the image acquisition module and the piezoelectric controller respectively.

2. The diamond lathe tool center height adjustment device according to claim 1, characterized in that: It also includes an adapter plate; the image acquisition module is arranged on the pneumatic conversion fixture through the adapter plate.

3. The diamond lathe tool center height adjustment device according to claim 2, characterized in that: The image acquisition module includes: a camera, a coaxial microscope tube, an imaging objective lens and a coaxial light source; the coaxial microscope tube is fixed to the adapter plate, the camera is arranged at one end of the coaxial microscope tube, the imaging objective lens is arranged at the other end of the coaxial microscope tube, and the coaxial light source is installed on the coaxial microscope tube.

4. The diamond lathe tool center height adjustment device according to claim 1, characterized in that: It also includes a lens barrel clamp; the coaxial microscope barrel is fixed on the adapter plate through the lens barrel clamp.

5. The diamond lathe tool center height adjustment device according to claim 1, characterized in that: It also includes a light source controller; the light source controller controls the light brightness and light wavelength of the coaxial light source.

6. The diamond lathe tool center height adjustment device according to claim 1, characterized in that: It also includes a tool holder; the diamond tool is installed on the piezoelectric ceramic lifting platform through the tool holder.

7. A method for adjusting the center height adjustment device of a diamond lathe tool according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: The ultra-precision machine tool controls the piezoelectric ceramic lifting platform to move along the X direction and the Z direction so that the diamond tool is imaged at the mirror point of the imaging object; The host computer controls the camera to turn on, and controls the light source controller to adjust the brightness of the coaxial light source; Setting the coarse adjustment movement step length, coarse adjustment speed, fine adjustment movement step length and fine adjustment speed of the piezoelectric ceramic lifting platform; The host computer controls the piezoelectric controller to move the piezoelectric ceramic lifting platform along the Y direction according to the coarse adjustment movement step and coarse adjustment speed; at the same time, each movement step of the piezoelectric ceramic lifting platform triggers the host computer to capture the image of the diamond tool through the camera; The host computer calculates the clarity of the diamond tool image and controls the piezoelectric ceramic lifting platform to move repeatedly until the maximum value of the clarity of the diamond tool image is obtained; Stopping the movement of the piezoelectric ceramic lifting platform and extracting the edge of the diamond tool image; Performing primitive segmentation on the edge of the diamond tool image to obtain the primary and secondary cutting edge edges and the tool tip arc edge of the diamond tool respectively; Performing linear fitting on the primary and secondary cutting edges to obtain an intersection position, and setting the intersection position as a tool tip position; Performing circle fitting on the arc edge of the tool tip, obtaining a circumscribed rectangle of the fitted circle, and setting it as a diamond tool ROI image; The host computer controls the piezoelectric controller to move the piezoelectric ceramic lifting platform along the Z direction according to the fine adjustment movement step and fine adjustment speed; at the same time, each movement step of the piezoelectric ceramic lifting platform triggers the host computer to capture the diamond tool ROI image through the camera; The host computer calculates the clarity of the diamond tool ROI image and controls the piezoelectric ceramic lifting platform to move repeatedly until the maximum value of the diamond tool ROI image clarity is obtained, thereby realizing a method for adjusting the center height of a diamond lathe tool.

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