阅读说明：本技术 一种基于薄膜应变计的铣削力测量仪 (Milling force measuring instrument based on film strain gauge ) 是由 丁杰雄 胡翀 赖俊杰 吴宇舟 段莹瑞 王伟 王林江 林震 王啸东 于 2021-10-18 设计创作，主要内容包括：本发明公开了一种基于薄膜应变计的铣削力测量仪,包括刀柄,刀柄上固定有机电装置,机电装置包括电池,薄膜应变计,信号处理电路和信号发射装置,电池分别与薄膜应变计,信号处理电路和信号发射装置电连接。电池负责供应能源,薄膜应变计负责感知因切削力而产生的刀柄表面应变信号,信号处理电路对薄膜应变计测量的信号进行采集、放大处理,信号发射装置将信号处理电路处理的信息传输到信号接收装置,并上传至上位机进行数据分析。(The invention discloses a milling force measuring instrument based on a film strain gauge, which comprises a tool handle, wherein an electromechanical device is fixed on the tool handle, the electromechanical device comprises a battery, the film strain gauge, a signal processing circuit and a signal emitting device, and the battery is respectively and electrically connected with the film strain gauge, the signal processing circuit and the signal emitting device. The battery is responsible for supplying the energy, and the film strain gauge is responsible for the perception handle of a knife surface strain signal that produces because of the cutting force, and signal processing circuit gathers, the amplification processing to the signal that the film strain gauge measured, and signal emission device transmits the information that signal processing circuit handled to signal receiving arrangement to upload to the host computer and carry out data analysis.)

1. The utility model provides a mill power measuring apparatu based on film strainometer which characterized in that: the electromechanical device comprises a battery, a film strain gauge, a signal processing circuit and a signal emitting device, wherein the battery is electrically connected with the film strain gauge, the signal processing circuit and the signal emitting device respectively; the battery is responsible for supplying the energy, and the film strain gauge is responsible for the perception handle of a knife surface strain signal that produces because of the cutting force, and signal processing circuit gathers, the amplification processing to the signal that the film strain gauge measured, and signal emission device transmits the information that signal processing circuit handled to signal receiving arrangement to upload to the host computer and carry out data analysis.

2. The thin film strain gauge-based milling force measuring instrument according to claim 1, wherein: the mounting method of the film strain gauge comprises the following steps:

s1, thinning the cutter handle;

s2, processing a film strain gauge placing area on the cylindrical surface of the cutter handle;

s3, performing plane cutting and polishing treatment in the region obtained in the step S2;

s4, mounting a film strain gauge on the placement area subjected to the cutting processing in the step S3;

and S5, the film strain gauge arranged in the step S4 decomposes a cutting force signal borne by the cutter handle and uploads the signal to an upper computer for data analysis.

3. The thin film strain gauge-based milling force measuring instrument according to claim 2, wherein: in the step S2, the number of the thin film strain gauge placing areas is four and the thin film strain gauge placing areas are distributed on the outer surface of the tool shank at intervals of 90 °.

4. The thin film strain gauge-based milling force measuring instrument according to claim 1, wherein: in the step S5, the cutting force can be decomposed into a force F in the axial direction_zForce F directed towards the center of the tool_xAnd a force F tangential to the tool_yWith the center point of the tool as the object of force analysis, F_z、F_xAnd F_yCan be decomposed into axial force F on the tool shank_zBending moment M_x、M_yThe surface of the tool shank generates tensile and compressive strain effects by the aid of the independent axial force, and main strains on the circumferential direction of the surface of the tool shank are consistent in size along the axial direction at the same axial height of the tool shank; the independent bending moment enables the surface of the tool shank to generate tensile and compressive strain effects, on the same height of the tool shank in the axial direction, main strain on the circumferential direction of the surface of the tool shank changes along the axial direction in a sine mode, two strains at 180-degree intervals are equal in magnitude and opposite in direction; the independent torque makes the surface of the tool shank generate a twisting effect, and the main strain on the circumferential direction of the surface of the tool shank is in a direction of 45 degrees with the axial direction at the same height of the tool shank in the axial direction, and the magnitude of the main strain is kept consistent.

5. The thin film strain gauge-based milling force measuring instrument according to claim 2, wherein: four thin film strain gauges in the thin film strain gauges form a thin film strain gauge group, the four thin film strain gauges are named as A1, A2, B1 and B2 respectively, the A1 and the A2 are used for sensing strain caused by torque T, and the B1 and the B2 are used for sensing strain caused by bending moment M and axial force F.

6. The thin film strain gauge-based milling force measuring instrument according to claim 5, wherein: the number of the film strain gauge groups is four, the film strain gauge groups are arranged at intervals of 90 degrees, the film strain gauge groups are respectively arranged into a first group of film strain gauges, a second group of film strain gauges, a third group of film strain gauges and a fourth group of film strain gauges, and the first group of film strain gauges, the second group of film strain gauges, the third group of film strain gauges and the fourth group of film strain gauges obtain axial force through superposition of signalsF_zThe induced strain signal is subtracted to obtain the bending moment M_xAnd M_yThe resulting strain signal.

7. The thin film strain gauge-based milling force measuring instrument according to claim 2, wherein: the film strain gauge is characterized in that the tool handle is of a revolving body structure, a tool handle groove is formed in the middle of the tool handle, and the film strain gauge placing area is located in the tool handle groove.

8. The thin film strain gauge-based milling force measuring instrument according to claim 2, wherein: the film strain gauge comprises an insulating layer (2), a strain layer (3) and a protective layer (4) which are arranged from bottom to top, wherein the insulating layer (2) is prepared on the surface of the knife handle through a magnetron sputtering technology and used for ensuring the electrical insulation between the strain layer (3) and the knife handle, the strain layer (3) comprises a strain grid set (5) and an electrode (6), the strain layer (3) adopts a photoetching and masking technology, the strain grid set (5) and the electrode (6) are prepared on the surface of the insulating layer through the magnetron sputtering technology and used for sensing a strain signal of the knife handle, and meanwhile, the strain layer is provided with an electrode connecting wire to be connected with an external circuit for processing the signal; the protective layer (4) is prepared on the strain layer (3) by adopting a magnetron sputtering technology and is used for preventing the interference of the external environment.

9. The thin film strain gauge-based milling force measuring instrument according to claim 8, wherein: the strain grid group is composed of a plurality of strain grids with different arrangement directions so as to sense strain caused by cutting forces in different directions, the strain grids are connected with electrodes, and the electrodes are electrically connected with a signal processing circuit through wires.

Technical Field

The invention belongs to the technical field of cutting force measuring devices, and particularly relates to a milling force measuring instrument based on a film strain gauge.

Background

In the mechanical cutting process, the cutting force is an important parameter, and the method can be used for predicting and evaluating the abrasion of a cutter and the quality of a machined part by monitoring the size and the direction of the cutting force, can also guide the adjustment of the machining parameter, and has great significance for realizing intelligent production and manufacturing.

The cutting force is generated at the point of cutting engagement of the tool with the workpiece, and can be measured at the workpiece end or the tool end according to newton's third law. For milling, a worktable type dynamometer can be used for measuring the cutting force of a workpiece end, but the worktable type dynamometer cannot be widely applied to production and machining due to the defects of complex clamping, limited size of a machined workpiece and the like; conversely, the above problems are well solved by measuring the cutting force of the tool tip.

The cutting force is measured by the tool end, and the commonly used method is to indirectly measure the cutting force by sensing the mechanical deformation of the tool end. For example, in milling operations, the cutting force may be measured by sensing the mechanical deformation of the tool shank; the sensing element commonly used therein is mainly a resistance type strain sensor, also called a resistance strain gauge, and the working principle thereof is as follows: when the external force/moment causes the mechanical deformation of the measured piece, the geometric shape of the sensitive material in the sensor is correspondingly changed to a certain extent, so that the resistance of the sensitive material is changed, the strain change of the measured piece can be measured by processing the electric signal caused by the resistance change, such as acquisition, amplification and the like, and the stress of the measured piece is indirectly measured.

The common resistance type strain sensor in the market is mainly of a sticking type resistance strain, and needs to be tightly attached to the surface of a measured object by using an adhesive for measurement, but the mode of combining the adhesive and the measured object brings certain problems of hysteresis and creep. If a stick-on strain gauge is used to measure the tool shank surface strain to measure the cutting force, the actual machining characteristics are accompanied: (1) the cutter rotates at high speed in the machining process and is accompanied by high-frequency vibration; (2) the temperature is higher; (3) the surface strain signal of the tool shank is weak due to the high rigidity of the tool shank; the defects of the sticking type strain gauge are more obvious, and weak strain signals on the surface of the knife handle are difficult to measure.

Disclosure of Invention

The invention aims to solve the problems and provides an integrated tool holder type cutting force measuring device, wherein a strain signal acquired based on a resistance type film strain gauge and a layout and design method thereof are adopted in the device, and an electromechanical device is fastened around a tool holder; the milling force measuring instrument is internally provided with a signal processing circuit and a signal transmitting device, signal data are transmitted to an upper computer to solve the cutting force, and the real-time wireless monitoring of the cutting force in the machining process is realized.

In order to solve the technical problems, the technical scheme of the invention is as follows: a milling force measuring instrument based on a thin film strain gauge comprises a cutter handle, wherein an electromechanical device is fixed on the cutter handle, the electromechanical device comprises a battery, the thin film strain gauge, a signal processing circuit and a signal transmitting device, and the battery is electrically connected with the thin film strain gauge, the signal processing circuit and the signal transmitting device respectively; the battery is responsible for supplying the energy, and the film strain gauge is responsible for the perception handle of a knife surface strain signal that produces because of the cutting force, and signal processing circuit gathers, the amplification processing to the signal that the film strain gauge measured, and signal emission device transmits the information that signal processing circuit handled to signal receiving arrangement to upload to the host computer and carry out data analysis.

Further, the installation method of the film strain gauge comprises the following steps:

s1, thinning the cutter handle;

s2, processing a film strain gauge placing area on the cylindrical surface of the cutter handle;

s3, performing plane cutting and polishing treatment in the region obtained in the step S2;

s4, mounting a film strain gauge on the placement area subjected to the cutting processing in the step S3;

and S5, the film strain gauge arranged in the step S4 decomposes a cutting force signal borne by the cutter handle and uploads the signal to an upper computer for data analysis.

Further, in the step S2, the number of the thin film strain gauge placing areas is four and the thin film strain gauge placing areas are distributed on the outer surface of the tool shank at intervals of 90 °.

Further, in the step S5, the cutting force can be decomposed into a force F along the axial direction_zForce F directed towards the center of the tool_xAnd a force F tangential to the tool_yWith the center point of the tool as the object of force analysis, F_z、F_xAnd F_yCan be decomposed into axial force F on the tool shank_zBending moment M_x、M_yThe surface of the tool shank generates tensile and compressive strain effects by the aid of the independent axial force, and main strains on the circumferential direction of the surface of the tool shank are consistent in size along the axial direction at the same axial height of the tool shank; the independent bending moment enables the surface of the tool shank to generate tensile and compressive strain effects, on the same height of the tool shank in the axial direction, main strain on the circumferential direction of the surface of the tool shank changes along the axial direction in a sine mode, two strains at 180-degree intervals are equal in magnitude and opposite in direction; the surface of the tool shank generates a twisting effect by the independent torque, and the main strain on the circumferential direction of the surface of the tool shank is in the direction of 45 degrees with the axial direction at the same height of the tool shank in the axial direction, and the magnitude of the main strain is kept consistent

Further, every four of the thin film strain gauges form a thin film strain gauge group, the four thin film strain gauges are respectively named as a1, a2, B1 and B2, the a1 and a2 are used for sensing the strain caused by the torque T, and the B1 and B2 are used for sensing the strain caused by the bending moment M and the axial force F.

Furthermore, the number of the thin film strain gauge groups is four, the thin film strain gauge groups are arranged at intervals of 90 degrees, the thin film strain gauge groups are respectively arranged into a first group of thin film strain gauges, a second group of thin film strain gauges, a third group of thin film strain gauges and a fourth group of thin film strain gauges, and the first group of thin film strain gauges, the second group of thin film strain gauges, the third group of thin film strain gauges and the fourth group of thin film strain gauges obtain axial force F through superposition of signals_zThe induced strain signal is subtracted to obtain the bending moment M_xAnd M_yThe resulting strain signal.

Further, the cutter handle is of a revolving body structure, a cutter handle groove is formed in the middle of the cutter handle, and the film strain gauge placing area is located in the cutter handle groove.

Furthermore, the thin film strain gauge comprises an insulating layer, a strain layer and a protective layer which are arranged from bottom to top, the insulating layer is prepared on the surface of the knife handle through a magnetron sputtering technology and used for ensuring the electrical insulation between the strain layer and the knife handle, the strain layer comprises a strain grid group and an electrode, the strain layer adopts a photoetching and masking technology, the strain grid group and the electrode are prepared on the surface of the insulating layer through the magnetron sputtering technology and used for sensing a strain signal of a tested piece, and meanwhile, the thin film strain gauge is provided with an electrode connecting lead which is connected with an external circuit to process the signal; the protective layer is prepared on the strain layer by adopting a magnetron sputtering technology and is used for preventing the interference of the external environment.

Furthermore, the strain grating group is composed of a plurality of strain gratings with different arrangement directions so as to sense the strain caused by the cutting force in different directions, the strain gratings are connected with electrodes, and the electrodes are electrically connected with the signal processing circuit through leads.

The invention has the beneficial effects that: according to the milling force measuring instrument based on the film strain gauge, strain signals acquired based on the resistance type film strain gauge and a layout and design method of the strain signals are adopted inside the instrument, an electromechanical device is fastened around a cutter handle, a signal processing circuit and a signal transmitting device are arranged inside the instrument, signal data are transmitted to an upper computer to solve cutting force, and real-time wireless monitoring of the cutting force in the machining process is achieved. The invention has simple structure, convenient manufacture, wide practical range and accurate measurement data.

Drawings

FIG. 1 is a schematic diagram of a thin film strain gauge based milling force measuring instrument according to the present invention;

FIG. 2 is a diagram illustrating the steps of mounting a thin film strain gauge according to the present invention;

FIG. 3 is a schematic view of the distribution of the thin film strain gauges on the tool shank of the present invention;

FIG. 4 is a cross-sectional schematic view of FIG. 3 of the present invention;

FIG. 5 is a schematic view of the construction of the inventive tool shank;

FIG. 6 is a schematic diagram of a thin film strain gauge of the present invention;

FIG. 7 is a schematic view of the structure of a strained layer of the present invention.

Description of reference numerals: 2. an insulating layer; 3. a strained layer; 4. a protective layer; 5. a strain gate group; 6. and an electrode.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments:

as shown in fig. 1 to 7, the milling force measuring instrument based on the thin film strain gauge provided by the invention comprises a tool handle, wherein an electromechanical device is fixed on the tool handle, the electromechanical device comprises a battery, the thin film strain gauge, a signal processing circuit and a signal emitting device, and the battery is electrically connected with the thin film strain gauge, the signal processing circuit and the signal emitting device respectively. The battery is responsible for supplying the energy, and the film strain gauge is responsible for the perception handle of a knife surface strain signal that produces because of the cutting force, and signal processing circuit gathers, the amplification processing to the signal that the film strain gauge measured, and signal emission device transmits the information that signal processing circuit handled to signal receiving arrangement to upload to the host computer and carry out data analysis.

In this embodiment, the thin film strain gauge is only one example of the present invention, and different thin film strain sensors can be replaced according to different use requirements during the actual use process, so as to increase the practicability of the present invention.

As shown in fig. 2, the method for mounting the thin film strain gauge includes the following steps:

and S1, thinning the cutter handle.

And S2, processing a film strain gauge placing area on the cylindrical surface of the cutter handle.

In step S2, the thin film strain gauge placement regions are four in number and distributed on the outer surface of the tool shank at 90 ° intervals.

S3, performing the plane cutting and polishing process in the region obtained in the step S2.

S4, the film strain gauge is attached to the placement area after the dicing process in step S3.

And S5, the film strain gauge arranged in the step S4 decomposes a cutting force signal borne by the cutter handle and uploads the signal to an upper computer for data analysis.

In step S5, the cutting force is decomposed into force F in the axial direction_zForce F directed towards the center of the tool_xAnd a force F tangential to the tool_yWith the center point of the tool as the object of force analysis, F_z、F_xAnd F_yCan be decomposed into axial force F on the tool shank_zBending moment M_x、M_yThe surface of the tool shank generates tensile and compressive strain effects by the aid of the independent axial force, and main strains on the circumferential direction of the surface of the tool shank are consistent in size along the axial direction at the same axial height of the tool shank; the independent bending moment enables the surface of the tool shank to generate tensile and compressive strain effects, on the same height of the tool shank in the axial direction, main strain on the circumferential direction of the surface of the tool shank changes along the axial direction in a sine mode, two strains at 180-degree intervals are equal in magnitude and opposite in direction; the independent torque makes the surface of the tool shank generate a twisting effect, and the main strain on the circumferential direction of the surface of the tool shank is in a direction of 45 degrees with the axial direction at the same height of the tool shank in the axial direction, and the magnitude of the main strain is kept consistent.

In this embodiment, the size of the film strain gauge is in the micro-nano level, the film strain sensor is prepared at the appropriate position on the cylindrical surface of the knife handle, and the micro-nano processing technology belongs to the micro-nano processing technology category. On the basis, proper plane cutting processing is carried out at the set position, and four parts of micro plane areas are obtained for preparing the thin film strain gauge.

Meanwhile, in order to improve the surface strain sensitivity of the tool shank and improve the measurement effect of the strain gauge, the tool shank is subjected to appropriate thinning treatment.

As shown in fig. 3, four of the thin film strain gauges constitute a thin film strain gauge group, and the four thin film strain gauges are respectively named as a1, a2, B1 and B2, a1 and a2 sense strain caused by torque T, and B1 and B2 sense strain caused by bending moment M and axial force F.

As shown in FIG. 4, the number of thin film strain gauge groups is four and spaced apart by 90 °, and the thin film strain gauge groups are each separately disposedThe first group of film strain gauges, the second group of film strain gauges, the third group of film strain gauges and the fourth group of film strain gauges are arranged, and the axial force F is obtained by superposition of signals of the first group of film strain gauges, the second group of film strain gauges, the third group of film strain gauges and the fourth group of film strain gauges_zThe induced strain signal is subtracted to obtain the bending moment M_xAnd M_yThe resulting strain signal.

In fig. 4, reference numerals "1, 2, 3, and 4" correspond to the first group of thin film strain gauges, the second group of thin film strain gauges, the third group of thin film strain gauges, and the fourth group of thin film strain gauges, respectively.

As shown in FIG. 5, the cutter handle is of a revolving body structure, a cutter handle groove is formed in the middle of the cutter handle, and the thin film strain gauge placing area is located in the cutter handle groove.

Through the structural improvement of the tool holder, the sensitivity of strain generated by the stress on the surface of the tool holder can be improved, and meanwhile, the processing precision can be influenced by controlling the degree of thinning well without influencing the structural characteristics of the tool holder too much.

As shown in fig. 6 and 7, the film strain gauge comprises an insulating layer 2, a strain layer 3 and a protective layer 4, wherein the insulating layer 2 is arranged from bottom to top, the insulating layer 2 is prepared on the surface of the knife handle through a magnetron sputtering technology and used for ensuring the electrical insulation between the strain layer 3 and the knife handle, the strain layer 3 comprises a strain grid group 5 and an electrode 6, the strain layer 3 adopts photoetching and masking technologies, the strain grid group 5 and the electrode 6 are prepared on the surface of the insulating layer through the magnetron sputtering technology and used for sensing a strain signal of the knife handle, and meanwhile, the film strain gauge is provided with an electrode connecting wire which is connected with an external circuit to process the signal. The protective layer 4 is prepared on the strain layer 3 by adopting a magnetron sputtering technology and is used for preventing the interference of the external environment.

The strain grid group 5 is composed of a plurality of strain grids with different arrangement directions so as to sense strain caused by cutting forces in different directions, the strain grids are connected with electrodes, and the electrodes are electrically connected with a signal processing circuit through leads.

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.