A smart cutting tool with embedded temperature sensor and a method of manufacturing the same

Abstract

This invention relates to an intelligent cutting tool with an embedded temperature sensor and its manufacturing method, belonging to the fields of cutting processing and advanced manufacturing technology. The invention provides an intelligent cutting tool with an embedded temperature sensor, comprising a shank and a cutting section. The cutting section has at least one mounting position at its tip. An intelligent insert is detachably mounted at the mounting position, and the intelligent insert has at least one temperature sensing circuit including a temperature sensor built-in. This invention places the temperature sensing circuit inside the insert and positions the junction at the tip and cutting edge, ensuring accurate temperature measurement of the cutting area. Furthermore, based on the principle of additive manufacturing, the insert is manufactured in an integrated, layered manner, minimizing the impact on the tool's performance and lifespan.

Description

Technical Field

[0001] This invention relates to an intelligent cutting tool with an embedded temperature sensor and its manufacturing method, belonging to the fields of cutting processing and advanced manufacturing technology. Background Technology

[0002] The acquisition and application of manufacturing process status data through sensors is fundamental to the realization of intelligent manufacturing equipment. The state of the cutting area during machining directly affects and reflects the quality of the part. Therefore, in the context of intelligent manufacturing, the location of sensors in machine tools is increasingly closer to the cutting area to obtain more direct and accurate status data. Since the material on the workpiece surface to be machined will be removed during machining, and mounting and unmounting sensors on the workpiece would affect production efficiency, mounting sensors on the cutting tool is a more feasible option.

[0003] Generally, cutting temperature, cutting force, cutting vibration, and other state parameters can reflect the state of the cutting process. Among these, measuring cutting temperature is simpler and more economical, and is widely used in engineering. However, due to interference from chips, cutting fluid, and other substances during the cutting process, direct measurement of the cutting temperature in the cutting zone is quite difficult. To more effectively, reliably, and conveniently measure the cutting temperature in the cutting zone using sensors, embedding the temperature sensor inside the tool and placing it as close to the cutting zone as possible is a reasonable choice.

[0004] Researchers have proposed several design schemes and implementation methods to address this issue. However, these schemes have not been able to embed the temperature sensor into the cutting tool without altering its cutting performance and lifespan. Furthermore, the tools remain inconvenient to use, and significant problems persist in engineering applications. A detailed analysis follows:

[0005] Patent CN102601399A proposes a smart cutting tool comprising a tool substrate and a functional coating. The functional coating includes a cutting coating on the tool substrate, a sensor sensing coating, and an outermost protective coating. The cutting coating is applied to the tool substrate, and the protective coating is applied to the surface of the sensor sensing coating. The sensor sensing coating consists of a piezoelectric thin film layer, an interdigital transducer array integrated therein, and a connected radio frequency antenna. In this solution, the functional coating of the cutting tool is achieved through a coating process, which is complex and economical. Furthermore, the bonding force between the substrate and the functional coating is limited, and the coating thickness is also limited. During cutting, the functional coating is easily damaged and loses its effectiveness under the action of cutting forces or after tool wear. In addition, temperature measurement by the interdigital transducer array has high requirements for acquisition, processing, and analysis, resulting in a complex system with low reliability and poor economy.

[0006] Patent CN103111642A proposes a smart cutting tool based on a surface acoustic wave (SAW) sensing system. A diamond cutting head is fixed to the front end of the cutting tool, and the cutting tool signal sensing area is located on the cutting tool behind the diamond cutting head. The SAW sensing system is fixed within this signal sensing area on the cutting tool. This solution, based on the principle of SAW sensing, has high requirements for signal acquisition, processing, and analysis. The system is complex, has low reliability, poor economic efficiency, and poor temperature sensing capability in the cutting area of ​​the diamond cutting head.

[0007] Patent CN104942318A discloses an intelligent transient cutting temperature-measuring tool, its manufacturing method, and a temperature measurement method. The tool includes a tool body, a thin-film thermocouple deposited on the tool body, electrodes, circuitry, and a temperature acquisition terminal. The thin-film thermocouple includes an insulating film deposited on the tool body, thermoelectrode one, thermoelectrode two, a Si3N4 protective film deposited on the insulating film, and lead-out circuitry. This solution measures temperature based on the thermocouple principle, and is simple and convenient. However, by depositing the thin-film thermocouple and Si3N4 protective film onto the substrate, the functional coating is easily damaged and loses its effectiveness under cutting forces or after tool wear.

[0008] Patent CN113732332A proposes a temperature-sensing cutting tool, consisting of a tool body made of structural material and a temperature sensing module made of thermistor ceramic. The tool body and the thermistor ceramic temperature sensing module are sintered together, and then the thermistor ceramic temperature sensing module is embedded into the tool body to obtain an intelligent cutting tool with temperature sensing function. In this design, the tool body and the thermistor ceramic temperature sensing module are manufactured separately, which compromises the integrity of the tool, alters the cutting surface, and affects the tool's cutting performance and service life. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides an intelligent cutting tool with an embedded temperature sensor, comprising a shank and a cutting section. The cutting section has a rake face, a primary flank face, and a secondary flank face, and the intersection of the rake face, the primary flank face, and the secondary flank face forms a cutting tip. The cutting tip of the cutting section has at least one mounting position. The rake face includes a pressure block, one end of which is fixed to the rake face, and the other end of which is located above the mounting position.

[0010] The intelligent cutting tool is provided with a first lead wire and a second lead wire connecting the tool holder and the cutting part;

[0011] The mounting position is detachably mounted with a smart blade, which has at least one cutting edge and at least one cutting tip. The pressure block presses against the smart blade at least partially. The smart blade has at least one temperature sensing circuit with a temperature sensor built in, which is connected to the first lead and the second lead.

[0012] In this invention, "above" refers to the direction in which each component faces away from the ground, and "below" refers to the direction in which each component faces towards the ground; the terms "first" and "second" are only used to distinguish similar components with different positions or characteristics, and have no other limiting meaning.

[0013] It should be understood that the shank and cutting part of the intelligent cutting tool of the present invention can be similar in shape to those of a conventional turning tool. Therefore, the positions of the rake face, main flank face, and secondary flank face can refer to the structure of a conventional turning tool. The mounting position can be a notch on the tool tip or a structure that can replace the tool tip. After the intelligent insert is installed in the mounting position, it can be fixed by a clamping block, and the intelligent insert can be removed from the mounting position by lifting the clamping block. The temperature sensing circuit includes a temperature sensor that can measure the temperature of the cutting area. The first lead and the second lead are connected to an external measuring circuit and are insulated from the shank.

[0014] Furthermore, the mounting position is a notch of the blade tip and has a first mounting surface, a second mounting surface, and a third mounting surface that are not parallel to each other. The first mounting surface is provided with a first lead electrode connected to the first lead wire, and the second mounting surface is provided with a second lead electrode connected to the second lead wire. Preferably, both the first lead electrode and the second lead electrode are flexible electrodes that can deform under pressure, thereby reducing the gap between the lead electrode and other electrodes.

[0015] In one embodiment of the present invention, the smart blade includes four temperature sensing circuits with identical structures. Each temperature sensing circuit includes a first thermoelectric electrode and a second thermoelectric electrode connected by a node. The first thermoelectric electrode and the second thermoelectric electrode are respectively provided with a first connection portion connected to the first lead electrode and a second connection portion connected to the second lead electrode.

[0016] It should be understood that two thermoelectrodes can form a thermocouple, which is a commonly used type of temperature sensor.

[0017] In one embodiment of the present invention, the node is disposed inside the cutting edge or inside the tip of the blade. This arrangement allows the node to be located closer to the cutting part, making the temperature of the cutting area measured by the temperature sensing circuit more accurate. The first connecting part and the second connecting part are respectively exposed on the surface of the smart blade in different directions.

[0018] The present invention also provides a method for preparing the intelligent insert of the intelligent cutting tool according to claim 1, characterized by comprising the following steps:

[0019] Step 1: Prepare ceramic slurry, wherein the ceramic slurry includes alumina ceramic slurry and at least one ceramic slurry containing a curing agent;

[0020] Step 2: Prepare the metal paste: The metal paste includes tungsten rhenium 5, tungsten rhenium 20, and copper paste;

[0021] Step 3: Based on the principle of additive manufacturing, the smart blade is manufactured in two layers from the outside to the inside. The outer layer material and the inner layer material of the smart blade are respectively selected as photocurable alumina ceramic slurry and alumina ceramic slurry; the first thermoelectric electrode is selected as tungsten rhenium 5 slurry, the second thermoelectric electrode is selected as tungsten rhenium 20 slurry, and the first connecting part and the second connecting part are both made of copper slurry.

[0022] Step 4: Based on the blade layering in Step 3 and the materials selected for the smart blade, the first thermal electrode, the second thermal electrode, the first connecting part, and the second connecting part, and based on the material extrusion process and additive manufacturing principle, further obtain the extrusion paths of different slurries (which can be calculated using slicing software).

[0023] Step 5: Blade Forming: According to the extrusion path of different slurries, various slurries are extruded in sequence to form intelligent blades; the extrusion order can be from the outside to the inside: first, the outer layer material is extruded, which is a light-cured alumina ceramic slurry, and it is cured at the same time as extrusion; then the inner layer material is extruded; in this way, the outer layer material is cured and then the inner layer is filled, which can keep the shape of the blade unchanged during the extrusion process.

[0024] Step 6: Pretreatment of the blade blank: Further photocuring the formed smart blade and heating it to 600-800℃ under vacuum conditions for 3-5 hours;

[0025] Step 7: Blade calcination: Continue heating to 1600-1800℃ and maintain for 2-5 hours, then allow to cool naturally to room temperature;

[0026] Step 8: Blade post-treatment: Remove impurities and foreign objects from the surface of the calcined smart blade, grind the blade surface to make it flat and smooth, and expose the first connecting part and the second connecting part on the surface;

[0027] Step 9: Quality Inspection: Install the smart blade into the mounting position, measure the continuity and resistance, and determine the effectiveness of the thermocouple circuit.

[0028] In one embodiment of the present invention, in step 1, the ceramic slurry includes an alumina ceramic slurry and a photocurable alumina ceramic slurry containing a photocuring agent; further, in step 5, when extruding the photocurable alumina ceramic slurry, the extruded slurry is irradiated with curing light corresponding to the photocuring wavelength, thereby curing it.

[0029] The beneficial effects of this invention are:

[0030] I. This invention places the temperature sensing circuit inside the cutting tool and positions the junction at the tip and edge of the tool, thus accurately measuring the temperature in the cutting area. Furthermore, since the cutting temperature distribution during the cutting process has a large gradient, the cutting temperature is high in the cutting area and the temperature on the tool away from the cutting area drops rapidly. Moreover, the temperature and its changes in the cutting area can better reflect the cutting state. Therefore, placing the temperature sensor close to the tip of the tool can more effectively determine the cutting state.

[0031] Second, this invention uses additive manufacturing principles to integrate and layer the cutting tool, which has little impact on the tool's performance and lifespan. Unlike processes that attach sensors to the cutting tool surface through coating or plating, or embed sensors in separately manufactured tool bodies, this invention includes a temperature sensing circuit with a temperature sensor hidden inside the intelligent cutting tool and is manufactured as a whole with the tool body, which has little impact on the tool's performance and lifespan, while also improving manufacturing efficiency.

[0032] Third, the temperature sensing circuit of this invention is built into the intelligent cutting tool and only the connection part of the electrode is exposed on the surface, which makes the temperature sensor, leads, electrodes and other components of the temperature sensing circuit have a longer service life, higher reliability, and better convenience and economy; at the same time, the structure of the temperature sensing circuit and temperature sensor manufactured as a whole is not easily damaged.

[0033] Fourth, it facilitates the assessment of wear and lifespan of intelligent cutting tools. During the cutting process, as tool wear increases, the temperature sensor gets closer to the cutting area, and the cutting temperature changes accordingly. Therefore, the wear of the cutting tool can be assessed through algorithms. In addition, when tool wear reaches a certain level or when tool chipping occurs, the embedded temperature sensor is damaged, and the characteristics of the measurement circuit also change, thus allowing the assessment of tool lifespan. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure in one embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the overall structure after disassembling the blade and the pressure block in one embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the mounting position portion in one embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure of the smart blade in one embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram of the temperature sensing circuit in one embodiment of the present invention;

[0039] In the figure, 1: handle, 2: smart blade, 3: clamping block, 4: fastener, 10: handle body, 11: first lead wire, 12: second lead wire, 13: fastener hole, 14: mounting position, 14A: first mounting surface, 14B: second mounting surface, 14C: third mounting surface, 15: first lead wire electrode, 16: second lead wire electrode, 20: smart blade body, 21: first temperature sensing circuit, 22: second temperature sensing circuit, 23: third temperature sensing circuit, 24: fourth temperature sensing circuit, 21A: first connecting part, 21B: second connecting part, 211: first thermoelectric electrode, 212: second thermoelectric electrode, 21N: junction, 21T: blade tip. Detailed Implementation

[0040] Example

[0041] like Figure 1 As shown, the present invention provides an intelligent cutting tool with an embedded temperature sensor, including a tool holder 1 and a cutting part. The cutting part has a rake face, a main flank face, and a secondary flank face, and the intersection of the rake face, the main flank face, and the secondary flank face forms a cutting tip. The cutting tip of the cutting part has at least one mounting position. The rake face includes a pressure block 3. One end of the pressure block 3 is fixed to the rake face by a fastener 4, and at least a portion of the other end of the pressure block 3 presses against the intelligent cutting tool 2.

[0042] like Figure 2 As shown, the intelligent cutting tool has a first lead 11 and a second lead 12 connecting the tool holder 1 and the cutting part; the mounting position 14 is detachably equipped with an intelligent blade 2, which has four cutting edges and four corresponding cutting tips. The intelligent blade 2 has four independent temperature sensing circuits, each including a temperature sensor, which are a first temperature sensing circuit 21, a second temperature sensing circuit 22, a third temperature sensing circuit 23, and a fourth temperature sensing circuit 24 with identical structures. The temperature sensing circuits are connected to the first lead 11 and the second lead 12.

[0043] Each of the temperature sensing circuits includes a first thermoelectric electrode 211 and a second thermoelectric electrode 212 connected by a node 21N. The first thermoelectric electrode 211 and the second thermoelectric electrode 212 are respectively provided with a first connection portion 21A connected to the first lead electrode 15 and a second connection portion 21B connected to the second lead electrode 16. The first and second connection portions of each temperature sensing circuit are exposed on different surfaces of the smart blade 2. For example, the first connection portion 21A and the second connection portion 21B of the first temperature sensing circuit 21 are exposed on surfaces S1 and S2 of the smart blade 2, respectively. The node 21N is located inside the cutting edge or inside the tip 21T. This arrangement allows the node 21N to be located closer to the cutting part, making the temperature of the cutting area measured by the temperature sensing circuit more accurate.

[0044] Furthermore, the mounting position 14 is a notch of the blade tip 21T and has a first mounting surface 14A, a second mounting surface 14B, and a third mounting surface 14C that are not parallel to each other. The first mounting surface 14A is provided with a first lead electrode 15 connected to the first lead wire 11, and the second mounting surface 14B is provided with a second lead electrode 16 connected to the second lead wire 12. The first lead electrode 15 and the second lead electrode 16 are both flexible electrodes, and the first lead electrode 15, the second lead electrode 16, the first lead wire 11, and the second lead wire 12 are all insulated from the handle portion 1.

[0045] When the smart blade 2 is installed in the mounting position 14, the surface of the smart blade 2 is in contact with the first mounting surface 14A, the second mounting surface 14B, and the third mounting surface 14C. Furthermore, the first connection part and the second connection part of any temperature sensing circuit can be connected to the first lead electrode 15 and the second lead electrode 16, respectively. Thus, the first lead 11, the first lead electrode 15, the first connection part, the first thermoelectric electrode 211, the junction 21N, the second thermoelectric electrode 212, the second connection part, the second lead electrode 16, and the second lead 12 form a circuit path.

[0046] The temperature sensing principle of this embodiment is as follows:

[0047] When a certain tip of the intelligent blade 2 is cutting, the first thermoelectric electrode 211 and the second thermoelectric electrode 212 form a thermocouple. The junction 21N near the tip 21T is the hot end of the thermocouple. A thermoelectric potential can be generated at the output end (i.e. the end of the first lead 11 and the second lead 12) of the circuit path formed by the first lead 11, the first lead electrode 15, the first connecting part, the first thermoelectric electrode 211, the junction 21N, the second thermoelectric electrode 212, the second connecting part, the second lead electrode 16, and the second lead 12. After measurement, the cutting temperature near the tip can be obtained.

[0048] The principle behind the wear and lifespan determination of the intelligent blade in this embodiment is as follows:

[0049] When a certain cutting tip 21T of the intelligent blade 2 performs cutting, the first thermoelectric electrode 211 and the second thermoelectric electrode 212 form a thermocouple. The junction 21N near the cutting tip is the hot end of the thermocouple, which can generate a thermoelectric potential at the output end (i.e., the end of the first lead 11 and the second lead 12) of the circuit path formed by the first lead 11, the first lead electrode 15, the first connecting part, the first thermoelectric electrode 211, the junction 21N, the second thermoelectric electrode 212, the second connecting part, the second lead electrode 16, and the second lead 12. When the wear of blade 2 reaches a certain threshold, the blade tip is damaged, the first thermoelectric electrode 211 and the second thermoelectric electrode 212 of the sensing circuit 21 are disconnected, the thermocouple is destroyed, and the above-mentioned circuit path is destroyed. The potential of the output end of the circuit path (i.e. the end of the first lead 11 and the second lead 12) changes. Based on this, it can be determined whether the wear of the smart blade 2 has reached the threshold. The size of the threshold can be set by the position of the node 21N of the first thermoelectric electrode 211 and the second thermoelectric electrode 212 of the sensing circuit 21 relative to the blade tip 21T.

[0050] The handle 1 is made of cemented carbide, the smart blade 2 is made of alumina ceramic, the first thermoelectric electrode 211 is made of tungsten-rhenium 5 (i.e., 95% tungsten and 5% rhenium), the second thermoelectric electrode 212 is made of tungsten-rhenium 20 (i.e., 80% tungsten and 20% rhenium), and the first connecting part 21A and the second connecting part 21B are made of copper.

[0051] Example 2

[0052] The present invention also provides a method for preparing the intelligent insert of the intelligent cutting tool according to claim 1, characterized by comprising the following steps:

[0053] Step 1: Prepare ceramic slurry, which includes alumina ceramic slurry and photocurable alumina ceramic slurry containing a photocuring agent;

[0054] Step 2: Prepare the metal paste: The metal paste includes tungsten rhenium 5, tungsten rhenium 20, and copper paste;

[0055] Step 3: Based on the principle of additive manufacturing, the smart blade is manufactured in two layers from the outside to the inside. The outer layer material and the inner layer material of the smart blade are respectively selected as photocurable alumina ceramic slurry and alumina ceramic slurry; the first thermoelectric electrode is selected as tungsten rhenium 5 slurry, the second thermoelectric electrode is selected as tungsten rhenium 20 slurry, and the first connecting part and the second connecting part are both made of copper slurry.

[0056] Step 4: Based on the blade layering in Step 3 and the materials selected for the smart blade, the first thermal electrode, the second thermal electrode, the first connecting part, and the second connecting part, and based on the material extrusion process and additive manufacturing principle, further obtain the extrusion paths of different slurries (which can be calculated using slicing software).

[0057] Step 5: Blade Forming: According to the extrusion path of different slurries, various slurries are extruded in sequence to form the intelligent blade; the extrusion order is from the outside to the inside: first, the outer layer material is extruded, which is a photocurable alumina ceramic slurry, and it is cured at the same time as extrusion; then the inner layer material is extruded; in this way, the outer layer material is cured and then the inner layer is filled, which can keep the shape of the blade unchanged during the extrusion process; when extruding the photocurable alumina ceramic slurry, curing light corresponding to the photocuring wavelength is used to irradiate the extruded slurry to cure it;

[0058] Step 6: Pretreatment of the blade blank: Further photocuring the formed smart blade and heating it to 600-800℃ under vacuum conditions for 3-5 hours;

[0059] Step 7: Blade calcination: Continue heating to 1600-1800℃ and maintain for 2-5 hours, then allow to cool naturally to room temperature;

[0060] Step 8: Blade post-treatment: Remove impurities and foreign objects from the surface of the calcined smart blade, grind the surface to make it flat and smooth, and expose the first connecting part and the second connecting part on the surface;

[0061] Step 9: Quality Inspection: Install the smart blade into the mounting position, measure the continuity and resistance, and determine the effectiveness of the thermocouple circuit.

[0062] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing intelligent cutting tool inserts, characterized in that, The intelligent cutting tool includes a shank portion and a cutting portion. The cutting portion has a rake face, a primary flank face, and a secondary flank face, and the intersection of the rake face, the primary flank face, and the secondary flank face forms a cutting tip. The cutting tip of the cutting portion has at least one mounting position. The rake face includes a pressure block, one end of which is fixed to the rake face, and the other end of which is located above the mounting position. The intelligent cutting tool is provided with a first lead wire and a second lead wire connecting the tool holder and the cutting part; The mounting position is detachably mounted with a smart blade, the smart blade having at least one cutting edge capable of cutting, the pressure block pressing against the smart blade at least partially, and the smart blade having at least one built-in temperature sensing circuit including a temperature sensor connected to the first lead and the second lead; The mounting position is the notch of the blade tip and has a first mounting surface, a second mounting surface and a third mounting surface that are not parallel to each other. The first mounting surface is provided with a first lead electrode connected to the first lead wire, and the second mounting surface is provided with a second lead electrode connected to the second lead wire. Each of the temperature sensing circuits includes a first thermoelectric electrode and a second thermoelectric electrode connected by a node. The first thermoelectric electrode and the second thermoelectric electrode are respectively provided with a first connection portion connected to the first lead electrode and a second connection portion connected to the second lead electrode. The method includes the following steps: Step 1: Prepare ceramic slurry, which includes alumina ceramic slurry and photocurable alumina ceramic slurry containing a photocuring agent; Step 2: Prepare the metal paste: The metal paste includes tungsten rhenium 5, tungsten rhenium 20, and copper paste; Step 3: Based on the principle of additive manufacturing, the smart blade is manufactured in two layers from the outside to the inside. The outer layer material and the inner layer material of the smart blade are respectively selected as photocurable alumina ceramic slurry and alumina ceramic slurry containing photocuring agent; the first hot electrode is selected as tungsten rhenium 5 slurry, the second hot electrode is selected as tungsten rhenium 20 slurry, and the first connecting part and the second connecting part are both made of copper slurry. Step 4: Based on the blade layering in Step 3 and the materials selected for the smart blade, the first thermal electrode, the second thermal electrode, the first connecting part, and the second connecting part, and based on the material extrusion process and additive manufacturing principle, further obtain the extrusion paths for different slurries; Step 5: Blade Forming: According to the extrusion path of different slurries, various slurries are extruded in sequence to form intelligent blades; Step 6: Pretreatment of the blade blank: Further photocuring the formed smart blade and heating it to 600-800℃ under vacuum conditions for 3-5 hours; Step 7: Blade calcination: Continue heating to 1600-1800℃ and maintain for 2-5 hours, then allow to cool naturally to room temperature; Step 8: Blade post-treatment: Remove impurities and foreign objects from the surface of the calcined smart blade, grind the surface to make it flat and smooth, and expose the first connecting part and the second connecting part on the surface; Step 9: Quality Inspection: Install the smart blade into the mounting position, measure the continuity and resistance, and determine the effectiveness of the thermocouple circuit.

2. The method according to claim 1, characterized in that, In step 5, when extruding the photocurable alumina ceramic slurry, the extruded slurry is irradiated with curing light corresponding to the photocuring wavelength to cure it.

3. The method according to claim 1, characterized in that, Both the first lead electrode and the second lead electrode are flexible electrodes.

4. The method according to claim 1, characterized in that, The smart blade contains four identical temperature sensing circuits.

5. The method according to claim 4, characterized in that, The node is located on the inner side of the blade.

6. The method according to claim 4, characterized in that, The first connecting portion and the second connecting portion are exposed on the surfaces of the smart blade in different directions.

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