Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
  • B24B49/003—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation involving acoustic means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
  • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
  • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
  • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
  • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
  • B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C3/00—Profiling tools for metal drawing; Combinations of dies and mandrels
  • B21C3/02—Dies; Selection of material therefor; Cleaning thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
  • B23Q17/09—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool
  • B23Q17/0904—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool before or after machining
  • B23Q17/0919—Arrangements for measuring or adjusting cutting-tool geometry in presetting devices
  • B23Q17/0928—Cutting angles of lathe tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
  • B23Q17/09—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool
  • B23Q17/0952—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool during machining
  • B23Q17/0957—Detection of tool breakage
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
  • B23Q17/09—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool
  • B23Q17/0952—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool during machining
  • B23Q17/098—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool during machining by measuring noise
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B41/00—Component parts such as frames, beds, carriages, headstocks
  • B24B41/007—Weight compensation; Temperature compensation; Vibration damping
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
  • F16C19/52—Bearings with rolling contact, for exclusively rotary movement with devices affected by abnormal or undesired conditions
  • F16C19/527—Bearings with rolling contact, for exclusively rotary movement with devices affected by abnormal or undesired conditions related to vibration and noise
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B19/00—Programme-control systems
  • G05B19/02—Programme-control systems electric
  • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
  • G05B19/406—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by monitoring or safety
  • G05B19/4065—Monitoring tool breakage, life or condition
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2322/00—Apparatus used in shaping articles
  • F16C2322/39—General build up of machine tools, e.g. spindles, slides, actuators
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/34—Director, elements to supervisory
  • G05B2219/34443—Sensors and actuator integrated into tool
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/37—Measurements
  • G05B2219/37027—Sensor integrated with tool or machine
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/37—Measurements
  • G05B2219/37434—Measuring vibration of machine or workpiece or tool

Definitions

• the present invention relates to manufacturing machine or tool elements and mechanical components that have an integrally mounted acoustic emissions sensor to produce a signal indicating operating conditions and parameters.
• Manufacture of articles for consumer and industrial use may employ metal removal operations (such as drilling, milling, turning, and grinding), metal forming and primary processes (sheet rolling, sheet forming, drawing, and ironing, in addition to forging and cold forming), as well as joining processes (such as welding).
• metal removal operations such as drilling, milling, turning, and grinding
• metal forming and primary processes sheet rolling, sheet forming, drawing, and ironing, in addition to forging and cold forming
• joining processes such as welding.
• plastic deformation is invariably involved. It occurs in welding due to solidification shrinkage (small strains).
• small strains In metal forming and other primary processes, larger shape changes occur which vary with the nature of the specific process (small, medium, and large strains).
• plastic strains imposed can be quite large. Grinding is an example.
• Plastic deformation in all crystalline materials involves defect processes traceable ultimately to the "line defects," i.e., crystal dislocations. Shape change or permanent strain is enforced by causing large scale dislocation activity, invo >llv ⁇ ing millions of dislocations per cm 3 or inch3" r
• Ceramic and ceramic-like materials (graphite in a lead pencil is an example) also produce substantial acoustic emission as a consequence of elastic energy release accompanying fracture. Large scale analog of this phenomenon are the seismic waves accompanying earthquakes. In this case, the displacements accompanying seismic wave propagation are large enough to be detected by even crude seismometers.
• Acoustic emission sensors have been advanced for mounting on machine tool and mechanical parts for sensing acoustic emissions. Conventionally, these sensors with inertial masses are mounted on a support for the tool or machine element being monitored. This results in mechanical filtering of acoustic emission signals between the mounting interfaces of the tool. Because the acoustic emission signals are relatively low level, and in a relatively high frequency range, the filtering results in the inability to accurately follow the pattern of acoustic emissions from a given tool or machine element.
• Commercially available sensors are coupled to the objects, generally by pressing the sensor against the surface of the object. Use of rubber bands is common, and sometimes adhesives are used to hold the sensor in place.
• any imperfection in the interface between the sensor and the object on which it is mounted also acts as a filter, and thus various coupling agents, such as liquids, are interposed between the sensor and the object.
• various coupling agents such as liquids
• transduction efficiency is low, and at the present time the manufacturers of existing acoustic emission detection systems recommend low noise, very high gain amplifier systems.
• the problems associated with the high gain amplifiers of course include any background noise, and rather complex circuitry for obtaining any type of a usable signal.
• piezoelectric material for sensing acoustic emissions is known, but these generally are mounted onto a sensor assembly having an inertial mass.
• the sensor assembly is mounted onto a support on the manufacturing tool or in the location where acoustic emission sensing is desired.
• a study of these types of devices is set forth in Ferro Electrics, 1981, Volume 32, page ' s 79-83, in the article entitled "Durable Lead Attachment Techniques for PVDF Polymer Transducers With Application to High Voltage Pulsed Ultrasonics,” by Scott et al.
• page 82 of the Scott article shows a response of two different types of sensors including a commercial broad band acoustic emission transducer, and the PVDF sensor under consideration.
• materials have atomic and intermolecular structures that are subject to shear, and void and discontinuity producing events. When such events occur, they release elastic strain energy in the form of stress waves. These waves propogate through the solid in the forms of acoustic waves, and velocity is determined by the structure and properties of the solid.
• the acoustic waves may possess frequencies up to several Mhz and are eventually dissipated by transmission reflection and refraction at the boundary surfaces of the solid and by irreversible processes within the solid, such as molecular shifts. Monitoring of these sound wave or acoustic wave changes also gives information about friction conditions between moving surfaces, and similar acoustic wave producing events.
• PVDF polyvinyldene flouride
• the present invention relates to an integrated acoustic emission sensor for real time monitoring of manufacturing processes, utilizing a piezoelectric material sensor coupled directly to the machining tooling element that is desired to be monitored.
• a piezoelectric material sensor coupled directly to the machining tooling element that is desired to be monitored.
• Use of an inertial mass, as in conventional bulky acoustic emission sensors, is completely dispensed with.
• the sensor is suitably connected to sensing circuitry for providing an output signal as a function of acoustic emissions in such tooling element.
• the sensor comprises a tool element having a piezoelectric material deposited thereon to form an integral sensor that will generate electrical signals in response to stress-wave imposed displacements in the part itself.
• Quartz, PZT and lithium compounds, as well as PVDF can be used for sensor elements.
• the present sensors do not suffer from the limitations of mechanical interface filtering, or from the need to have complex mounting techniques for the sensors themselves. Need for an additional inertial mass is also eliminated. By eliminating the inertial mass, the bulky conventional A.E. Transducer is replaced with a compact planar transducer, which is easily mounted integrally in tools and mechanical parts.
• the senor is preferrably deposited directly on the surface of the machine element, such as a disposable cutting tool insert, a tool die or punch, a drawing die, or similar tooling or machine elements.
• machine element includes any type of machine work element that is moved relative to a part being worked upon, which movement results in acoustic vibrations that can be sensed.
• the integral sensors are shown in the present specification, and of course any desired type of sensing circuitry can be utilized to provide the output signal that can be used for further processing, control, alarms, or the like.
• the acoustic sensors of the present invention can also be mounted onto thin metal substrates (without any significant mass) and lightly loaded against the tool as is shown in one form of the invention, to provide indications of actual fracture.
• Present acoustic ' emission sensors have significant mass which limits response.
• the mechanical filtering that occurs using a thin metal strip pressed against the tooling element is not a significant factor, primarily because the sensor is a very low mass system.
• very accurate acoustic emission sensors can be used in a wide variety of applications.
• Deposited piezoelectric sensors can be used for sensing the breakage of tools or inserts, the break or fracture of the work material being processed by the tool, as well as to detect metal-to-metal contact in a lubricated tool system, such as in a punch where the moving parts generate frictional forces as a function of lubrication.
• Sensors of this form constructed directly on mechanical components such as gears, cams, roller or ball bearings, etc., allow pitting, wear, micro- cracking and other deterioration processes to also be detected.
• the acoustic emission transducers can be used to sense fracture, cracking, micro-cracking, pitting and friction involved in a process or an operation, as much as changes in friction during processing or mechanical component use.
• the piezoelectric acoustic emission sensors are easily deposited in place in batch processes so costs are kept low.
• Figure 1 is a perspective view of a machine or cutting tool support having a disposable cutting insert with sensors made according to the present invention deposited thereon;
• Figure 2 is a perspective view of a typical cutting tool insert or cutting tool showing integral piezoelectric sensors made according the present invention mounted on the top and side surfaces thereof;
• Figure 3 is an enlarged sectional view of a tool insert as shown in Figure 2 showing in enlarged scale the construction of the deposited piezoelectric sensors formed thereon;
• Figure 4 is a typical block diagram for a circuit useful for analyzing outputs from sensors of the present invention
• Figure 5 is a graphical representation of a voltage signal that is delivered from a piezoelectric acoustic emission sensor made according to the present invention at time of a change in conditions at the cutting tool
• Figure 6 is a schematic representation of an unbonded, low mass, " acoustic emission sensor strip held in place on a cutting tool insert;
• Figure 7 is a sectional view of the sensor used in the device of Figure 6;
• Figure 8 is a cross-sectional representation of a wire drawing die with a acoustic emission sensor made according to the present invention deposited thereon;
• Figure 9 is a schematic cross-sectional view of a typical deep drawing punch and die set, with acoustic emission sensors made according to the present invention deposited on both the punch and the die for sensing conditions that occur during the deep draw forming operation;
• Figure 10 is a side view of a bearing having a piezoelectric acoustic emission sensor made according to the present invention deposited thereon;
• Figure 11 is a sectional view taken on line 11—11 in Figure 10; and Figure 12 is a side view of a typical gear component having an acoustic emission sensor made according to the present invention deposited therein.
• Figures 1-3 show a preferred embodiment of the present sensor on a cutting insert or cutting tool 20 that is made in a conventional manner, and generally rectilinear or circular disc in configuration.
• Such cutting inserts are made of a suitable carbide, ceramic, or high speed steel material.
• the cutting insert 20 is held in a tool holder 17 with a clamp finger 18, that is held in place with a screw 18A.
• the cutting insert 20 seats down onto a shoulder surface of the tool holder 17 and is clamped in place with the clamp 18.
• a corner 11 of the cutting insert 20 can be sharpened for cutting,
• the cutting edge of the insert 20 can be configured as desired.
• the tool holder 17 has a receptacle 12 for receiving and supporting a suitable integrated circuit chip 13 that can include signal conditioning and signal amplification instrumentation for the sensors on the tool insert 20.
• the cutting insert 20 is shown in more detail in Figures 2 and 3, and includes a first sensor portion 25 mounted on a surface 26 of the cutting insert 20, and in addition it has sensors 28 and 29 shown on the lateral sides thereof. These sensors can be on any desired surface of the cutting insert, and as shown in Figure 3 a sensor 30 is positioned on the side of the cutting insert opposite from the sensor 25. Each of the sensors 25, 28, 29 and 30 shown are configured in substantially the same manner. Each sensor includes a deposited layer of piezoelectric material that is the active element.
• the layer can be deposited by radio frequency sputtering, reactive sputtering or other physical vapor deposition techniques directly on the tool insert surfaces. Suitable masking of course will be provided.
• the piezoelectric layer can be covered with a deposited conductive layer, so that contacts for taking off signals can be easily connected.
• thick film (silk-screening) technology can be utilized for depositing the layer of piezoelectric material for the sensor. Also bonding piezoceramic transducer elements onto disposable cutting inserts can be achieved so long as the bond makes the sensor integral therewith.
• Each of the sensors is constructed substantially identically and includes a deposited layer of piezoelectric material indicated generally at 32, a conductive layer 33 that is deposited on top of the piezoelectric layer for providing electrical interface, and- an insulating protective layer 34 deposited over the conductive layer 33.
• the cutting insert 20 as shown when it is working and cutting material, will set up internal elastic wave emissions from a variety of dislocation interactions, and these elastic wave emissions are propagated as sound waves through the cutting insert to the exterior surfaces, where they affect the piezoelectric layer 32 of each of the sensors at the interface 35 of the piezoelectric layer and the cutting insert, the wave compresses the piezoelectric layer and that provides the piezoelectric voltage effect which causes a voltage differential with respect to the interface indicated at 36 between the conductive layer 33 and the piezoelectric layer 32.
• the piezoelectric layer can be any desired type of piezoelectric material, including various polymers or oxides. Additionally, the piezoelectric material in layer 32 can be deposited in an internal layer of the cutting tool insert if the cutting insert is constructed in layers. Zinc oxide is one example of a piezomaterial film suitable for constructing integral acoustic emission transducers of the present invention. Aluminum nitride, lithium niobate, PZT, or other desired materials also can be deposited or bonded to the cutting insert.
• the sensor layer thickness is substantially enlarged in Figure 3, and actually is a very thin film.
• the conductive layer 33 and the insulating layer 34 are also quite thin, so that the cutting tool insert is not substantially enlarged.
• a backing plate can be used on the underside of the cutting insert with an opening so that the sensor 30, for example, will fit n the opening and is not subjected to compressional forces when the cutting insert is clamped into place.
• the output from the piezoelectric sensor, for example, the sensor 25, is connected through a suitable lead 38 to sensing and processing circuitry.
• the circuitry can be that shown in the block diagram of Figure 4.
• the sensor is represented at 25, and the signal coming along the line 38 is amplified in the first stage amplifier 40, and is fed to a fast Fourier transform analyzer or other suitable analyzer circuitry indicated generally at 41.
• the output of the analyzer circuitry is provided to a controller 45 that can be used for monitoring a machine tool, for example, or controlling other processes as desired.
• the controller output along the line 45 can be fed to an actuator 46 or alarm, or a similar output module such as a recorder for recording the acoustic emissions that are sensed.
• This circuitry is conventional, and is shown by way of illustration only.
• Figure 5 is a graphical representation of a typical output from an acoustic emission sensor mode according to the present invention placed on a cutting tool insert such as that shown at 20, and using a deposited zinc oxide film.
• the plot of Figure 5 shows time versus output voltage
• the spike shown at 48 is a typical output that is sensed by the piezoelectric transducer during the fracture mode of the tool insert, because of acoustic emissions caused by such fracture.
• the time relationship of the major outputs are identical between commercial acoustic emission sensors and sensors of the present invention which indicates that the acoustic emissions are being sensed by the integral sensors disclosed herein.
• the present sensors provide a much greater output because of the lack of mechanical filtering due to interfaces and because the sensors are directly associated with the cutting insert or other tooling element that is being monitored.
• the present invention does not use an inertial mass. By dispensing with the mass, a sensitive transducer, compact in size and low in cost, can be constructed on any manufacturing tooling or mechanical component. Scope of AE monitoring for f ilure/fracture monitoring and detection is greatly expanded.
• FIG. 6 A modified form of the invention is shown in Figure 6, wherein a tool holder 50 has a standard cutting insert or cutting tool 51 mounted thereon. A clamp 52 is used for clamping the cutting tool 51 in place on its support surface. As shown a housing 53 is recessed into a provided receptacle below the support surface 54 of the tool holder, and an acoustic emission sensor assembly indicated generally at 55 is supported with respect to the housing under a biasing load from a light spring 56.
• the sensor 55 comprises a layer of piezoelectric material deposited onto a very thin metal base that is substantially assless, so that it does not respond to accelerations, but senses acoustic emission.
• the contact of the piezoelectric material between the surface of the cutting tool 51 and the surface of its mounting strip is such that the acoustic waves in the cutting insert cause a voltage to be generated in the sensor.
• the sensor is made the same as that shown in Figure 3 except the layer of piezoelectric material is deposited on a strip of metal instead of the cutting insert. The strip is biased against the insert 51.
• Figure 7 is a typical showing of the piezoelectric sensor 55, including a light metal plate 58 that is substantially massless, and a suitable piezoelectric layer 59 deposited thereon.
• a conductive layer 60 is applied as in Figure 3, and if desired, an insulative layer 61 may be deposited on the sensor in the same manner as in the first form of the invention.
• the light spring 56 is made so that is will contact the conducting layer through an opening in the insulative layer 60.
• An amplifier 63 can be mounted directly into a tool holder in a provided receptacle, and as shown a lead 64 coupled to spring 56 carries the signals generated by the acoustic emissions acting on piezoelectric layer 59.
• the signals at the amplifier input are ampli ied and provided on an amplifier output line 65 to suitable processing circuitry.
• This type of sensor 55 will work efficiently only with a low mass base or strip 58. Large mass sensors cause excessive filtering because of acceleration forces on the sensor.
• the low mass, deposited layer piezoelectric sensor will provide acoustic emission sensing directly from a cutting insert 51 or other machining element.
• a wire drawing die 68 is shown schematically, and is used for drawing a wire along a central axis indicated at 69.
• the die 68 has a die opening 70 for swaging the wire that is being drawn to the right size.
• the die 68 has an acoustic emission sensor indicated at 71 deposited directly on a surface 72 of the die adjacent to the die opening.
• the sensor 71 is constructed as shown in Figure 3, with a piezoelectric layer deposited directly on the die.
• FIG 9 a schematic showing of a sheet metal cup forming die 75 is shown.
• a punch 76 is used for drawing a blank as it is moved through the die.
• the die 75 has a die opening 78 through which the punch 76 will be pushed for forming a blank indicated generally at 80 into a deep drawn cup or the like.
• a suitable acoustic emission sensor 82 comprising a layer of piezoelectric material deposited directly on the die
• a second acoustic emission sensor 83 comprises a piezoelectric layer deposited directly on the punch
• the lubrication between the blank 80 and the surfaces of the die and punch can be determined by sensing the changes in acoustic emissions as the blank 80 is being formed.
• a hold down or pressure pad is shown schematically at 84 for restraining the outer edge portions of the blank to control the drawing operation. If the friction forces increase because of a lack of proper lubrication between the blank and the surfaces supporting the blank, the acoustic emissions also increase in intensity and in frequency. The acoustic emissions will be accurately sensed without mechanical filtering of the acoustic signals.
• Figures 10 and 11 are views of a mechanical component comprising a bearing 90 that can be either a ball or a roller bearing, with an integral acoustic emission transducer 91 placed thereon.
• the transducer 91 may be deposited on the peripheral surfaces (circumferential surface of the outer race, or the lateral surfaces of either the inner or outer race) of the mechanical component to monitor frictional conditions, lubrication, cracking and micro-cracking on the ball or roller path.
• the transducer also can detect pitting of the ball or roller path pitting during operation of this and similar mechanical elements.
• the acoustic emission sensor or transducer may be deposited on the peripheral surfaces (circumferential surface of the outer race, or the lateral surfaces of either the inner or outer race) of the mechanical component to monitor frictional conditions, lubrication, cracking and micro-cracking on the ball or roller path.
• the transducer also can detect pitting of the ball or roller path pitting during operation of this and similar mechanical elements.
• FIG. 91 can be constructed as described before, by directly depositing a layer of piezoelectric material in place and using a conductive film and insulative protective coating.
• Figure 12 is a schematic drawing of a gear component 93 with an integral acoustic emission transducer 94 positioned thereon. As in the case of bearings, acoustic emission transducers are directly deposited on an appropriate non-wearing surface of the gear component. Continuous monitoring enables identification of gear tooth wear, cracking, pitting, and other deleterious events which ultimately lead to component failure.
• the AE transducer can be applied to cams and other machine elements as well.
• the integral sensors can be mounted directly on tooling elements of various configurations, including the use with cutting inserts or cutting tools, punches, dies and the like.
• the integral acoustic emission sensors or transducers may be used to sense breakage of a tool, breakage or fracture of the work material being processed by a tool, as well as to detect conditions of metal-to-metal contact in lubricated tool systems and tool and work piece contact for cutting tool systems.
• the sensors shown in Figures 6 and 7, for example, having a separate base on which the piezoelectric layer is deposited, are primarily used for high output signals, such as occurs if a tool or metal part being worked would fracture.
• the acoustic emission signals obtained from the sensors disclosed herein provide direct information indicating conditions of a machine tooling element.
• the sensors made according to the present invention give very high response to various phenomena acting on tooling elements. There is no filtering by mechanical interfaces between the tooling elements and their mountings, and thus direct monitoring of conditions can be obtained.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Human Computer Interaction (AREA)
• Manufacturing & Machinery (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
• Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
• Force Measurement Appropriate To Specific Purposes (AREA)

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• 1988
  • 1988-06-17 EP EP88906437A patent/EP0419460A1/de not_active Withdrawn
  • 1988-06-17 WO PCT/US1988/002094 patent/WO1989012528A1/en not_active Application Discontinuation
  • 1988-07-06 CA CA000571289A patent/CA1322111C/en not_active Expired - Fee Related

Non-Patent Citations (1)

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