阅读说明：本技术 一种基于在线检测的微波旋磁铁氧体制备方法 (Microwave gyromagnetic ferrite preparation method based on online detection ) 是由 张方远 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种基于在线检测的微波旋磁铁氧体制备方法,包括如下步骤：混合；一次球磨；预烧；二次球磨；制料粉造粒,并通过在线含水率检测装置检测料粉的含水率；压制成型；烧结；磨加工；对完成磨加工的工件通过表面检测系统进行表面检测；记录连续存在表面缺陷的工件数量为N；若N的数值大于表面检测系统内存储的预设值；则启动警报装置；在工件完成后端上增设表面检测系统进行表面检测；检测表面是否存在表面缺陷；并记录连续存在缺陷工件的数量,及时检测产线状态；且增加在线含水率检测装置检测料粉的含水率,使得影响产品质量参数可视化；随时监测各道工序参数且能更快的排查出问题点。(The invention discloses a microwave gyromagnetic ferrite preparation method based on online detection, which comprises the following steps: mixing; performing primary ball milling; pre-burning; performing secondary ball milling; granulating the material powder, and detecting the water content of the material powder by an online water content detection device; pressing and forming; sintering; grinding; carrying out surface detection on the workpiece subjected to grinding processing by a surface detection system; recording the number of workpieces with continuous surface defects as N; if the numerical value of N is larger than a preset value stored in the surface detection system; the alarm device is started; a surface detection system is additionally arranged at the rear end of the finished workpiece for surface detection; detecting whether the surface has surface defects; recording the number of workpieces with continuous defects, and detecting the state of a production line in time; the water content of the material powder detected by the online water content detection device is increased, so that the product quality parameters are influenced to be visualized; each process parameter is monitored at any time and the problem points can be detected more quickly.)

1. A microwave gyromagnetic ferrite preparation method based on online detection is characterized by comprising the following steps: the method comprises the following steps:

step 1: mixing; with NiO, CuO, ZnO and Fe₂O₃As raw material, according to the molecular formula Ni_0.2Cu_0.2Zn _0.6Fe₂ O₄The ratio of the medium metal elements is converted into NiO, CuO, ZnO and Fe₂O₃Weighing and mixing the materials according to the mass percentage;

step 2: performing primary ball milling; performing primary ball milling for 10 hours to fully mix the raw materials to obtain mixed powder after the primary ball milling;

and step 3: pre-burning; putting the mixed powder obtained in the step 2 after the primary ball milling in an oven, drying at the temperature of 120 ℃, then putting the dried mixed powder in a sintering furnace for primary presintering at the presintering temperature of 820 ℃ for 3 hours, and cooling to room temperature along with the furnace to obtain presintering powder after the primary presintering;

and 4, step 4: performing secondary ball milling; performing secondary ball milling on the pre-sintered powder obtained in the step 3 after the primary pre-sintering to obtain mixed powder after the secondary ball milling;

and 5: granulating the material powder, and detecting the water content of the material powder by an online water content detection device; adding 15 wt% of oxalic acid into the mixed powder obtained in the step 4 after the secondary ball milling to obtain powder, detecting the water content and then granulating;

and 5: pressing and forming; after granulation, pressing into a ring with the thickness of 2-6 mm;

step 6: sintering; putting the pressed and formed workpieces into a sintering furnace according to a certain placing sequence for sintering;

and 7: grinding;

and 8: carrying out surface detection on the workpiece subjected to grinding processing by a surface detection system; detecting whether the surface has surface defects including cracks and/or gaps; if the surface defects are detected, pushing the workpiece into a region to be recovered through a pushing device;

and step 9: recording the number of workpieces with continuous surface defects as N; if the numerical value of N is larger than a preset value stored in the surface detection system; the alarm device is started; the surface detection comprises the upper surface detection and the lower surface detection of the workpiece and the side surface detection of the workpiece;

step 10: and baking silver on the workpiece with qualified surface detection.

2. The method for preparing microwave gyromagnetic ferrite based on online detection according to claim 1, wherein the method comprises the following steps: the surface detection system comprises a workpiece top surface image acquisition device, a workpiece bottom surface image acquisition device and a workpiece side surface image acquisition device, wherein the workpiece top surface image acquisition device, the workpiece bottom surface image acquisition device and the workpiece side surface image acquisition device are connected with an image processing system, and whether cracks and/or gaps exist on the top surface, the bottom surface and the side surface of the workpiece is identified through the image processing system;

a method for an image processing system to identify the presence of cracks and/or chips on the top, bottom, and side surfaces of a workpiece, comprising the steps of:

s1: numbering the acquired top surface image, bottom surface image and side surface image of the workpiece to form a first image to be detected, a second image to be detected and a third image to be detected;

s2: extracting a first image to be detected, and preprocessing the image, including geometric correction, radiation correction and denoising;

s3: determining the boundary contour of a workpiece in the first image to be detected through Canny operator edge detection, and extracting an image in the boundary contour;

s4: converting the image acquired in step S3 into a first to-be-detected grayscale image;

s5: acquiring a central point pixel gray value of the first to-be-detected gray image in the step S4, and radiating outwards in a circumferential manner by taking the central point as a circle center; comparing the difference value between the gray value of the pixel of the adjacent point and the gray value of the central point to obtain a difference value T1; and recording the comparison quantity as S1; if T1 is less than or equal to 10; recording the gray value of the adjacent point; if T1 is more than 10, discarding the gray value of the adjacent point; and so on, when the value of S1 is greater than 50% of the image pixel points, the recorded gray values of all the adjacent points are averaged to obtain a standard gray value; forming a standard gray image, wherein the gray value of each pixel point of the standard gray image is a standard gray value, and the pixel of the standard gray image is the same as the first to-be-detected gray image;

s6: performing AND operation on the standard gray image and the first to-be-detected gray image to obtain pixel points which are different from the standard gray image in the first to-be-detected gray image;

s7: judging whether the distinguishing pixel points are cracks or gaps; if the distinguishing pixel points are in linear arrangement, judging the distinguishing pixel points to be cracks; if the distinguishing pixel points are arranged in a block shape, the distinguishing pixel points are judged to be gaps;

s8: extracting a second image to be detected, and judging whether the bottom surface of the workpiece has a crack or a notch according to the steps S1-S7;

s9: extracting a third image to be detected, and forming a second gray image to be detected according to the steps S1-S4;

s10: acquiring a central point pixel gray value of the second gray image to be detected in the step S9, and radiating outwards in a rectangular manner by taking the central point as a center; comparing the difference value between the gray value of the pixel of the adjacent point and the gray value of the central point to obtain a difference value T2; and recording the comparison quantity as S2; if T2 is less than or equal to 10; recording the gray value of the adjacent point; if T2 is more than 10, discarding the gray value of the adjacent point; and so on, when the value of S2 is greater than 50% of the image pixel points, the recorded gray values of all the adjacent points are averaged to obtain a standard gray value; forming a standard gray image, wherein the gray value of each pixel point of the standard gray image is a standard gray value, and the pixel of the standard gray image is the same as the second gray image to be detected;

s11: performing AND operation on the standard gray image and the second to-be-detected gray image to obtain pixel points which are different from the standard gray image in the second to-be-detected gray image;

s12: judging whether the distinguishing pixel points are cracks or gaps; if the distinguishing pixel points are in linear arrangement, judging the distinguishing pixel points to be cracks; if the distinguishing pixel points are arranged in block, the distinguishing pixel points are judged to be gaps.

3. The method for preparing microwave gyromagnetic ferrite based on online detection according to claim 1, wherein the method comprises the following steps: the online moisture content detection device comprises a first conveying rail; the side edge of the first conveying track is provided with an installation frame, a rotary testing machine head is connected to the installation frame, and a near-infrared moisture meter is arranged on the rotary testing machine head.

4. The method for preparing microwave gyromagnetic ferrite based on online detection according to claim 3, wherein the method comprises the following steps: the rotary testing machine head comprises a hollow shell, a rotating shaft is arranged at the bottom of the hollow shell and connected with the mounting frame through a bearing, and the tail end of the rotating shaft is connected with an output shaft of the first motor.

5. The method for preparing microwave gyromagnetic ferrite based on online detection according to claim 2, wherein the method comprises the following steps: the surface detection system comprises a vibration disc, a first lifting frame assembly is connected to the tail end of an output channel of the vibration disc, the first lifting frame assembly comprises a supporting plate, and the bottom of the supporting plate is connected with a piston rod of a first air cylinder; in an initial state, the supporting plate and the tail end of the output channel of the vibration disc are in the same plane and are connected with each other; the detection channel is perpendicular to the tail end of the output channel of the vibration disk and is positioned above the output channel of the vibration disk; a workpiece top surface side surface detection station and a workpiece bottom surface detection station are sequentially arranged along the detection channel; the workpiece top surface image acquisition device and the workpiece side surface image acquisition device are arranged on a workpiece top surface side surface detection station and comprise a first shooting chamber, the first shooting chamber is positioned above the detection channel, and a first camera device is arranged at the top of the first shooting chamber; the side part of the first shooting chamber is provided with scanning and shooting equipment and further comprises a workpiece fixing disc assembly, the workpiece fixing disc assembly comprises a first tray, the bottom of the first tray is connected with a second cylinder, and the bottom end of the second cylinder is connected with a first motor output shaft; the first tray is driven by a second cylinder to move up and down, and the initial state of the first tray and the detection channel are on the same plane and are connected with each other; the top surface of the first tray is provided with a plurality of air holes, the first tray is hollow, the bottom of the first tray is provided with an exhaust hole, and the exhaust hole is connected with a first micro air pump;

when the workpiece is conveyed to the first tray through the detection channel, the first micro air pump sucks air to suck the workpiece; the first tray rises into the first shooting chamber, and the first camera device shoots the top surface of the first tray; the first motor drives the first tray to rotate, and the scanning camera equipment scans to obtain a side image of the workpiece;

the workpiece bottom surface image acquisition device comprises a second shooting cavity arranged at the top of the detection channel, a third cylinder is arranged at the top of the second shooting cavity, the third cylinder is connected with a sucker assembly, the workpiece bottom surface image acquisition device further comprises a second camera, the second camera is arranged on the side wall of the second shooting cavity through a fourth cylinder, and during shooting, a second camera is positioned at the bottom of the workpiece.

6. The method for preparing microwave gyromagnetic ferrite based on online detection according to claim 5, wherein the method comprises the following steps: the sucking disc subassembly includes the second tray, be provided with a plurality of gas pockets on the bottom surface of second tray, inside cavity, the top is provided with the through-hole, is provided with the miniature air pump of second on the through-hole.

7. The method for preparing microwave gyromagnetic ferrite based on online detection according to claim 5, wherein the method comprises the following steps: the end part of the detection channel is provided with a first pushing device, the first pushing device comprises a first pushing plate, the first pushing plate is connected with a fifth cylinder, and the first pushing plate and the detection channel are on the same plane and used for pushing the workpiece on the supporting plate into the detection channel.

8. The method for preparing microwave gyromagnetic ferrite based on online detection according to claim 7, wherein the method comprises the following steps: a second material pushing device and a third material pushing device are arranged on the side part of the detection channel; the structures of the second material pushing device and the third material pushing device are consistent with those of the first material pushing device, the second material pushing device and the workpiece top side surface detection station are correspondingly provided with a first region to be recovered, which is used for pushing a workpiece with surface defects on the top surface or the side surface of the workpiece, into the opposite side, and the third material pushing device and the workpiece bottom surface station are correspondingly provided with a second region to be recovered, which is used for pushing the workpiece with surface defects on the bottom surface of the workpiece, into the opposite side, which is provided with a workpiece bottom surface detection station.

Technical Field

The invention relates to the technical field of manufacturing of gyromagnetic ferrite, in particular to a microwave gyromagnetic ferrite preparation method based on online detection.

Background

Microwave ferrite is also called gyromagnetic ferrite, and is a ferrite material, wherein under the action of a high-frequency magnetic field, when plane-polarized electromagnetic waves are transmitted in the ferrite according to a certain direction, a polarization plane can continuously rotate around the transmission direction. The ferromagnetic resonance magnetic material has the properties of small ferromagnetic resonance line width, large spin wave resonance line width, low saturation magnetization, small magnetocrystalline anisotropy constant, low dielectric loss, stability, high performance and the like in a low frequency band. The material is manufactured by adopting an electronic ceramic process and hot-pressing sintering or sintering in an oxygen atmosphere, and is mainly used for manufacturing millimeter-wave ferrite devices.

The ferrite is prepared by powder mixing, die casting, sintering, machining and silver coating at present; however, in the production and polishing processes of ferrite magnetic sheets obtained in industrial production, the defect problems of fracture marks, gaps and the like of partial magnetic sheets cannot be avoided, and in the existing assembly line production process, due to the characteristic of unobvious defects, accurate distinguishing and identification are difficult to be carried out in a mechanical mode, so that a method of manual visual identification is mostly adopted, a large amount of manual assistance for distinguishing is required in the defective product distinguishing production process, the production efficiency is low, and the rapid and high-quality production cannot be met;

and when a defective sample is found, the parameters of each process need to be checked, and the existing influence parameters comprise raw material formula content, ferrite granulation powder water content, pressing pressure, sintering temperature, grinding force and the like, wherein except for weighing a small amount of sample for the ferrite granulation powder water content, drying, re-weighing and calculating the water content, other main parameters can be controlled and monitored on line, so that if the ferrite granulation powder water content is detected on line continuously, whether the parameters of each process are proper or not can be checked more quickly.

Disclosure of Invention

The invention aims to provide a microwave gyromagnetic ferrite preparation method based on online detection, which is used for solving the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a microwave gyromagnetic ferrite preparation method based on online detection comprises the following steps:

step 1: mixing; with NiO, CuO, ZnO and Fe₂O₃As raw material, according to the molecular formula Ni_0.2Cu_0.2Zn_0.6Fe₂O₄The ratio of the medium metal elements is converted into NiO, CuO, ZnO and Fe₂O₃Weighing and mixing the materials according to the mass percentage;

step 2: performing primary ball milling; performing primary ball milling for 10 hours to fully mix the raw materials to obtain mixed powder after the primary ball milling;

and step 3: pre-burning; putting the mixed powder obtained in the step 2 after the primary ball milling in an oven, drying at the temperature of 120 ℃, then putting the dried mixed powder in a sintering furnace for primary presintering at the presintering temperature of 820 ℃ for 3 hours, and cooling to room temperature along with the furnace to obtain presintering powder after the primary presintering;

and 4, step 4: performing secondary ball milling; performing secondary ball milling on the pre-sintered powder obtained in the step 3 after the primary pre-sintering to obtain mixed powder after the secondary ball milling;

and 5: granulating the material powder, and detecting the water content of the material powder by an online water content detection device; adding 15 wt% of oxalic acid into the mixed powder obtained in the step 4 after the secondary ball milling to obtain powder, detecting the water content and then granulating;

and 5: pressing and forming; after granulation, pressing into a ring with the thickness of 2-6 mm;

step 6: sintering; putting the pressed and formed workpieces into a sintering furnace according to a certain placing sequence for sintering;

and 7: grinding;

and 8: carrying out surface detection on the workpiece subjected to grinding processing by a surface detection system; detecting whether the surface has surface defects including cracks and/or gaps; if the surface defects are detected, pushing the workpiece into a region to be recovered through a pushing device;

and step 9: recording the number of workpieces with continuous surface defects as N; if the numerical value of N is larger than a preset value stored in the surface detection system; the alarm device is started; the surface detection comprises the upper surface detection and the lower surface detection of the workpiece and the side surface detection of the workpiece;

step 10: and baking silver on the workpiece with qualified surface detection.

Preferably, the surface detection system comprises a workpiece top surface image acquisition device, a workpiece bottom surface image acquisition device and a workpiece side surface image acquisition device, wherein the workpiece top surface image acquisition device, the workpiece bottom surface image acquisition device and the workpiece side surface image acquisition device are connected with the image processing system, and whether cracks and/or gaps exist on the top surface, the bottom surface and the side surface of the workpiece is identified through the image processing system;

a method for an image processing system to identify the presence of cracks and/or chips on the top, bottom, and side surfaces of a workpiece, comprising the steps of:

s1: numbering the acquired top surface image, bottom surface image and side surface image of the workpiece to form a first image to be detected, a second image to be detected and a third image to be detected;

s2: extracting a first image to be detected, and preprocessing the image, including geometric correction, radiation correction and denoising;

s3: determining the boundary contour of a workpiece in the first image to be detected through Canny operator edge detection, and extracting an image in the boundary contour;

s4: converting the image acquired in step S3 into a first to-be-detected grayscale image;

s5: acquiring a central point pixel gray value of the first to-be-detected gray image in the step S4, and radiating outwards in a circumferential manner by taking the central point as a circle center; comparing the difference value between the gray value of the pixel of the adjacent point and the gray value of the central point to obtain a difference value T1; and recording the comparison quantity as S1; if T1 is less than or equal to 10; recording the gray value of the adjacent point; if T1 is more than 10, discarding the gray value of the adjacent point; and so on, when the value of S1 is greater than 50% of the image pixel points, the recorded gray values of all the adjacent points are averaged to obtain a standard gray value; forming a standard gray image, wherein the gray value of each pixel point of the standard gray image is a standard gray value, and the pixel of the standard gray image is the same as the first to-be-detected gray image;

s6: performing AND operation on the standard gray image and the first to-be-detected gray image to obtain pixel points which are different from the standard gray image in the first to-be-detected gray image;

s7: judging whether the distinguishing pixel points are cracks or gaps; if the distinguishing pixel points are in linear arrangement, judging the distinguishing pixel points to be cracks; if the distinguishing pixel points are arranged in a block shape, the distinguishing pixel points are judged to be gaps;

s8: extracting a second image to be detected, and judging whether the bottom surface of the workpiece has a crack or a notch according to the steps S1-S7;

s9: extracting a third image to be detected, and forming a second gray image to be detected according to the steps S1-S4;

s10: acquiring a central point pixel gray value of the second gray image to be detected in the step S9, and radiating outwards in a rectangular manner by taking the central point as a center; comparing the difference value between the gray value of the pixel of the adjacent point and the gray value of the central point to obtain a difference value T2; and recording the comparison quantity as S2; if T2 is less than or equal to 10; recording the gray value of the adjacent point; if T2 is more than 10, discarding the gray value of the adjacent point; and so on, when the value of S2 is greater than 50% of the image pixel points, the recorded gray values of all the adjacent points are averaged to obtain a standard gray value; forming a standard gray image, wherein the gray value of each pixel point of the standard gray image is a standard gray value, and the pixel of the standard gray image is the same as the second gray image to be detected;

s11: performing AND operation on the standard gray image and the second to-be-detected gray image to obtain pixel points which are different from the standard gray image in the second to-be-detected gray image;

s12: judging whether the distinguishing pixel points are cracks or gaps; if the distinguishing pixel points are in linear arrangement, judging the distinguishing pixel points to be cracks; if the distinguishing pixel points are arranged in block, the distinguishing pixel points are judged to be gaps.

Preferably, the online moisture content detection device comprises a first conveying rail; the side edge of the first conveying track is provided with an installation frame, a rotary testing machine head is connected to the installation frame, and a near-infrared moisture meter is arranged on the rotary testing machine head.

Preferably, the rotary testing machine head comprises a hollow shell, a rotating shaft is arranged at the bottom of the hollow shell and connected with the mounting frame through a bearing, and the tail end of the rotating shaft is connected with an output shaft of the first motor.

Preferably, the surface detection system comprises a vibration disc, a first lifting frame assembly is connected to the tail end of an output channel of the vibration disc, the first lifting frame assembly comprises a supporting plate, and the bottom of the supporting plate is connected with a piston rod of a first air cylinder; in an initial state, the supporting plate and the tail end of the output channel of the vibration disc are in the same plane and are connected with each other; the detection channel is perpendicular to the tail end of the output channel of the vibration disk and is positioned above the output channel of the vibration disk; a workpiece top surface side surface detection station and a workpiece bottom surface detection station are sequentially arranged along the detection channel; the workpiece top surface image acquisition device and the workpiece side surface image acquisition device are arranged on a workpiece top surface side surface detection station and comprise a first shooting chamber, the first shooting chamber is positioned above the detection channel, and a first camera device is arranged at the top of the first shooting chamber; the side part of the first shooting chamber is provided with scanning and shooting equipment and further comprises a workpiece fixing disc assembly, the workpiece fixing disc assembly comprises a first tray, the bottom of the first tray is connected with a second cylinder, and the bottom end of the second cylinder is connected with a first motor output shaft; the first tray is driven by a second cylinder to move up and down, and the initial state of the first tray and the detection channel are on the same plane and are connected with each other; the top surface of the first tray is provided with a plurality of air holes, the first tray is hollow, the bottom of the first tray is provided with an exhaust hole, and the exhaust hole is connected with a first micro air pump;

when the workpiece is conveyed to the first tray through the detection channel, the first micro air pump sucks air to suck the workpiece; the first tray rises into the first shooting chamber, and the first camera device shoots the top surface of the first tray; the first motor drives the first tray to rotate, and the scanning camera equipment scans to obtain a side image of the workpiece;

the workpiece bottom surface image acquisition device comprises a second shooting cavity arranged at the top of the detection channel, a third cylinder is arranged at the top of the second shooting cavity, the third cylinder is connected with a sucker assembly, the workpiece bottom surface image acquisition device further comprises a second camera, the second camera is arranged on the side wall of the second shooting cavity through a fourth cylinder, and during shooting, a second camera is positioned at the bottom of the workpiece.

Preferably, the sucker assembly comprises a second tray, a plurality of air holes are formed in the bottom surface of the second tray, the second tray is hollow, a through hole is formed in the top of the second tray, and a second miniature air pump is arranged on the through hole.

Preferably, a first pushing device is arranged at the end part of the detection channel and comprises a first pushing plate, the first pushing plate is connected with the fifth cylinder, and the first pushing plate and the detection channel are on the same plane and used for pushing the workpiece on the supporting plate into the detection channel.

Preferably, a second material pushing device and a third material pushing device are arranged on the side portion of the detection channel; the structures of the second material pushing device and the third material pushing device are consistent with those of the first material pushing device, the second material pushing device and the workpiece top side surface detection station are correspondingly provided with a first region to be recovered, which is used for pushing a workpiece with surface defects on the top surface or the side surface of the workpiece into the opposite side, and the third material pushing device and the workpiece bottom surface station are correspondingly provided with a second region to be recovered, which is used for pushing the workpiece with surface defects on the bottom surface of the workpiece into the opposite side.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a microwave gyromagnetic ferrite preparation method based on-line detection, wherein a surface detection system is additionally arranged at the rear end of a finished workpiece for surface detection; detecting whether the surface has surface defects; recording the number of workpieces with continuous defects, and detecting the state of a production line in time; the water content of the material powder detected by the online water content detection device is increased, so that the product quality parameters are influenced to be visualized; each process parameter is monitored at any time and the problem points can be detected more quickly.

Drawings

FIG. 1 is a schematic structural diagram of an on-line moisture content detection device according to the present invention;

FIG. 2 is a schematic view of the structure of FIG. 1 in another direction;

FIG. 3 is a schematic structural view of a first lift frame assembly of the present invention;

FIG. 4 is a schematic diagram of a surface inspection system according to the present invention;

FIG. 5 is a schematic structural diagram of a workpiece image capture device according to the present invention;

fig. 6 is a schematic view of a second image pickup apparatus mounting structure of fig. 5.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1-6, the present invention provides a technical solution:

a microwave gyromagnetic ferrite preparation method based on online detection comprises the following steps:

step 1: mixing; with NiO, CuO, ZnO and Fe₂O₃As raw material, according to the molecular formula Ni_0.2Cu_0.2Zn_0.6Fe₂O₄The ratio of the medium metal elements is converted into NiO, CuO, ZnO and Fe₂O₃Weighing and mixing the materials according to the mass percentage;

step 2: performing primary ball milling; performing primary ball milling for 10 hours to fully mix the raw materials to obtain mixed powder after the primary ball milling;

and step 3: pre-burning; putting the mixed powder obtained in the step 2 after the primary ball milling in an oven, drying at the temperature of 120 ℃, then putting the dried mixed powder in a sintering furnace for primary presintering at the presintering temperature of 820 ℃ for 3 hours, and cooling to room temperature along with the furnace to obtain presintering powder after the primary presintering;

and 4, step 4: performing secondary ball milling; performing secondary ball milling on the pre-sintered powder obtained in the step 3 after the primary pre-sintering to obtain mixed powder after the secondary ball milling;

and 5: granulating the material powder, and detecting the water content of the material powder by an online water content detection device; adding 15 wt% of oxalic acid into the mixed powder obtained in the step 4 after the secondary ball milling to obtain powder, detecting the water content and then granulating;

and 5: pressing and forming; after granulation, pressing into a ring with the thickness of 2-6 mm;

step 6: sintering; putting the pressed and formed workpieces into a sintering furnace according to a certain placing sequence for sintering;

and 7: grinding;

and 8: carrying out surface detection on the workpiece subjected to grinding processing by a surface detection system; detecting whether the surface has surface defects including cracks and/or gaps; if the surface defects are detected, pushing the workpiece into a region to be recovered through a pushing device;

and step 9: recording the number of workpieces with continuous surface defects as N; if the numerical value of N is larger than a preset value stored in the surface detection system; the alarm device is started; the surface detection comprises the upper surface detection and the lower surface detection of the workpiece and the side surface detection of the workpiece;

step 10: and baking silver on the workpiece with qualified surface detection.

The surface detection system comprises a workpiece top surface image acquisition device, a workpiece bottom surface image acquisition device and a workpiece side surface image acquisition device, wherein the workpiece top surface image acquisition device, the workpiece bottom surface image acquisition device and the workpiece side surface image acquisition device are connected with an image processing system, and whether cracks and/or gaps exist on the top surface, the bottom surface and the side surface of the workpiece is identified through the image processing system;

a method for an image processing system to identify the presence of cracks and/or chips on the top, bottom, and side surfaces of a workpiece, comprising the steps of:

s1: numbering the acquired top surface image, bottom surface image and side surface image of the workpiece to form a first image to be detected, a second image to be detected and a third image to be detected;

s2: extracting a first image to be detected, and preprocessing the image, including geometric correction, radiation correction and denoising;

s3: determining the boundary contour of a workpiece in the first image to be detected through Canny operator edge detection, and extracting an image in the boundary contour;

s4: converting the image acquired in step S3 into a first to-be-detected grayscale image;

s5: acquiring a central point pixel gray value of the first to-be-detected gray image in the step S4, and radiating outwards in a circumferential manner by taking the central point as a circle center; comparing the difference value between the gray value of the pixel of the adjacent point and the gray value of the central point to obtain a difference value T1; and recording the comparison quantity as S1; if T1 is less than or equal to 10; recording the gray value of the adjacent point; if T1 is more than 10, discarding the gray value of the adjacent point; and so on, when the value of S1 is greater than 50% of the image pixel points, the recorded gray values of all the adjacent points are averaged to obtain a standard gray value; forming a standard gray image, wherein the gray value of each pixel point of the standard gray image is a standard gray value, and the pixel of the standard gray image is the same as the first to-be-detected gray image;

s6: performing AND operation on the standard gray image and the first to-be-detected gray image to obtain pixel points which are different from the standard gray image in the first to-be-detected gray image;

s7: judging whether the distinguishing pixel points are cracks or gaps; if the distinguishing pixel points are in linear arrangement, judging the distinguishing pixel points to be cracks; if the distinguishing pixel points are arranged in a block shape, the distinguishing pixel points are judged to be gaps;

s8: extracting a second image to be detected, and judging whether the bottom surface of the workpiece has a crack or a notch according to the steps S1-S7;

s9: extracting a third image to be detected, and forming a second gray image to be detected according to the steps S1-S4;

s10: acquiring a central point pixel gray value of the second gray image to be detected in the step S9, and radiating outwards in a rectangular manner by taking the central point as a center; comparing the difference value between the gray value of the pixel of the adjacent point and the gray value of the central point to obtain a difference value T2; and recording the comparison quantity as S2; if T2 is less than or equal to 10; recording the gray value of the adjacent point; if T2 is more than 10, discarding the gray value of the adjacent point; and so on, when the value of S2 is greater than 50% of the image pixel points, the recorded gray values of all the adjacent points are averaged to obtain a standard gray value; forming a standard gray image, wherein the gray value of each pixel point of the standard gray image is a standard gray value, and the pixel of the standard gray image is the same as the second gray image to be detected;

s11: performing AND operation on the standard gray image and the second to-be-detected gray image to obtain pixel points which are different from the standard gray image in the second to-be-detected gray image;

s12: judging whether the distinguishing pixel points are cracks or gaps; if the distinguishing pixel points are in linear arrangement, judging the distinguishing pixel points to be cracks; if the distinguishing pixel points are arranged in block, the distinguishing pixel points are judged to be gaps.

The online moisture content detection device comprises a first conveying track 1; the side of the first conveying track is provided with a mounting frame 2, the mounting frame is connected with a rotary testing machine head 3, the rotary testing machine head is provided with a near infrared moisture meter 4, the rotary testing machine head comprises a hollow shell 5, the bottom of the hollow shell is provided with a rotating shaft 6, the rotating shaft is connected with the mounting frame through a bearing 7, and the tail end of the rotating shaft is connected with an output shaft of a first motor 8.

The surface detection system comprises a vibration disc 9, a first lifting frame assembly 11 is connected to the tail end of an output channel 10 of the vibration disc 9, the first lifting frame assembly comprises a supporting plate 12, and the bottom of the supporting plate is connected with a piston rod of a first air cylinder 13; in an initial state, the supporting plate and the tail end of the output channel of the vibration disc are in the same plane and are connected with each other; the vibration disc is characterized by further comprising a detection channel 14, wherein the detection channel is perpendicular to the tail end of the output channel of the vibration disc and is positioned above the output channel of the vibration disc; a workpiece top surface side surface detection station 15 and a workpiece bottom surface detection station 16 are sequentially arranged along the detection channel; the workpiece top surface image acquisition device and the workpiece side surface image acquisition device are arranged on a workpiece top surface side surface detection station and comprise a first shooting chamber 17, the first shooting chamber is positioned above the detection channel, and the top of the first shooting chamber is provided with a first camera 18; the side part of the first shooting chamber is provided with a scanning camera device 19 and further comprises a workpiece fixing disc assembly, the workpiece fixing disc assembly comprises a first tray 20, the bottom of the first tray is connected with a second air cylinder 21, and the bottom end of the second air cylinder is connected with a first motor output shaft 22; the first tray is driven by a second cylinder 21 to move up and down, and the initial state of the first tray and the detection channel are on the same plane and connected with each other; the top surface of the first tray is provided with a plurality of air holes, the first tray is hollow, the bottom of the first tray is provided with an air outlet hole, and the air outlet hole is connected with a first micro air pump 24;

when the workpiece is conveyed to the first tray through the detection channel, the first micro air pump sucks air to suck the workpiece; the first tray rises into the first shooting chamber, and the first camera device shoots the top surface of the first tray; the first motor drives the first tray to rotate, and the scanning camera equipment scans to obtain a side image of the workpiece;

work piece bottom surface image acquisition device shoots the cavity 25 including the second that sets up and detect the passageway top, the second shoots the cavity top and is provided with third cylinder 26, the third cylinder is connected with the sucking disc subassembly, still includes second camera equipment 27, second camera equipment passes through fourth cylinder 28 and sets up on the lateral wall of second shooting cavity, and during the shooting, second camera equipment camera is located the work piece bottom, the sucking disc subassembly includes second tray 29, be provided with a plurality of gas pockets on the bottom surface of second tray, inside cavity, the top is provided with the through-hole, is provided with the miniature air pump 30 of second on the through-hole.

A first pushing device 31 is arranged at the end part of the detection channel, the first pushing device comprises a first push plate, the first push plate is connected with a fifth cylinder 32, the first push plate and the detection channel are on the same plane and used for pushing the workpiece on the supporting plate into the detection channel, and a second pushing device 33 and a third pushing device 34 are arranged at the side part of the detection channel; the structures of the second material pushing device and the third material pushing device are consistent with those of the first material pushing device, the second material pushing device and the workpiece top side surface detection station are correspondingly provided with a first zone to be recovered 35 used for pushing a workpiece with surface defects on the top surface or the side surface of the workpiece into the opposite side, and the third material pushing device and the workpiece bottom surface station are correspondingly provided with a second zone to be recovered 36 used for pushing the workpiece with surface defects on the bottom surface of the workpiece into the opposite side.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.