An inspection apparatus for a rotary machine

Abstract

Disclosed is an inspection apparatus 200 for a rotary machine having a rotary assembly, wherein the inspection apparatus comprises: a sensor 202 coupled to a rotatory assembly and configured to monito

Description

The present disclosure relates to an inspection apparatus and method for a rotary machine; in particular, an inspection apparatus and method for identifying and predicting wear and damage developed on the bearings of the rotary machine. BACKGROUND Rotary machines are used in a wide range of applications, from the production of simple cylindrical parts to the creation of complex geometrical shapes, making them indispensable in many industries. For example, rotary machines may comprise mill machines, mill-turn machines, drill machines, grinding machines, and lathes. The maintenance and inspection of rotary machines are critical for ensuring operational efficiency, product quality, and safety in manufacturing environments. Regular inspection checks on these machines help identify wear and tear, mechanical issues, or misalignments before they lead to significant downtime, costly repairs, or compromised product quality. The regular inspection check may involve checking the spindle alignment to ensure that it is true to the rotary machine’s rotating axis. This might include run-out tests, which measure the variation of the spindle's rotational accuracy, and checks for bearing wear or noise, which can indicate a need for maintenance or replacement. It would be advantageous to improve one, or all, of these features. SUMMARY In one embodiment of the present invention, there is provided an inspection apparatus for a rotary machine having a rotary assembly, wherein the inspection apparatus comprises: a sensor coupled to a rotatory assembly and configured to monitor a property of the rotary machine in response to an excitation of the rotary assembly from an impact strike test; and wherein the inspection apparatus is configured to enable repeatable and consistent implementation of the impact strike test to derive a frequency response function of the rotary assembly from the property. Optionally, the sensor comprises: an accelerometer; and / or a displacement transducer; and / or a laser vibrometer. Optionally, wherein the rotary machine comprises: a lathe; and / or a drill; and / or a mill; and / or a mill-turn machine; and / or a grinder. Optionally, wherein the rotary assembly comprises: a spindle configured to rotate; and a rotary holder coupled to the spindle; a drawbar arrangement that connects the spindle with rotary holder; and configured to secure a cutting tool and / or a work piece. Optionally, wherein the sensor comprises: a securing mechanism configured to provide a releasable coupling of the sensor to the rotary holder. Optionally wherein the property comprises a signal data property comprising; a force value; and / or an acceleration value; and / or a displacement value; and / or a velocity value. Optionally, wherein impact strike test is configured to be performed by a strike impact hammer. Optionally, wherein the impact strike test comprises: a first set of impact strike tests comprising a test sequence having the steps: one or more first strike test on the rotary holder in a first direction; and one or more second strike tests on the rotary holder in a second direction. Optionally, wherein the sensor is configured to transmit an inspection signal to a data processor carrying information of the property; wherein the data processor is configured to receive the inspection signal and determine the rotary assembly compliance to an inspection criterion. Optionally, wherein the transmission of the inspection signal is performed by a wireless connection to a remote server remote computing hardware and / or wired connection to a computing hardware; and wherein the data processor may be housed within the sensor or may be a standalone hardware. Optionally, wherein the data processor within the computing hardware is configured to process the inspection signal thereby determining a first test frequency response function to the first set of impact strike tests. Optionally, wherein the data processor accesses a memory storage configured to log the first test frequency response function. Optionally wherein the impact strike comprises: a second impact strike test comprising: repeating the test sequence steps. Optionally, wherein the data processor is configured to process the inspection signal thereby determining a second test frequency response function to the second impact strike test. Optionally, wherein the memory storage is configured to log the second test frequency response. Optionally, wherein the data processor is configured to provide comparative analysis of the difference between the first test frequency response function and the second test frequency response function thereby generating a variation value compared to their corresponding historic values. Optionally, wherein the data processor is configured to implement a machine learning algorithm where the algorithm identifies the extent of variations within the frequency response function based on the comparative analysis in order to generate and assess against pass tolerance value. Optionally, wherein the machine learning algorithm is configured to perform regression analysis. Optionally, wherein the data processor further comprises a memory storage and is configured to store a pass tolerance value. Optionally, wherein the inspection criteria is passed if the variation value is less than or equal to the pass tolerance value otherwise the inspection criteria is failed Optionally further comprising: an outer profile configured to provide an outer radial perimeter; and an internal profile configured to provide an internal radial perimeter; and a strike surface arranged on the outer radial perimeter configured to receive the strike impact test. Optionally the rotary holder further comprising: a threaded box connection arranged on the outer radial perimeter and configured to receive the sensor of claims 1 to 23, and wherein the rotary holder of claim 23 arranged such that the threaded box connection is positioned 180 degrees from the opposing strike surface. In one embodiment of the present invention, there is provided a method of inspecting a rotary assembly having a spindle and / or a rotary holder comprising the steps of: coupling a sensor to the rotary holder; and performing a first set of strike impact tests on the rotary assembly and generating a first frequency response function results; performing a second set of strike impact tests on the rotary assembly and generating a second frequency response function results; performing comparative analysis on the first frequency response function and the second frequency response function thereby determining compliance to an inspection criterion. Optionally wherein the method further comprises transmitting an inspection signal to computer hardware, the computer hardware comprising a data processor, wherein the is configured to process the inspection signal thereby determining a first test frequency response function to the first set of impact strike tests and second frequency response function to the second set of impact strike tests and performing comparative analysis on the first frequency response function and the second frequency response function thereby determining compliance to an inspection criterion. Optionally the method further comprising the step of analysing the variations within the frequency response function based on its historic values and determining the current health status of the rotary assembly by applying machine learning algorithms and predicting future health and its remaining life. BRIEF DESCRIPTION OF THE DRAWINGS The disclosure is described in further detail below by way of example and with reference to the accompanying drawings, in which: figure la is a schematic of a known rotary machine configured as a lathe; figure lb is a schematic of a known rotary machine configured as a milling machine, figure 2a is a diagram showing an inspection apparatus for a rotary machine comprising a rotary assembly in accordance with a first embodiment of the present disclosure; figure 2b is a diagram showing how an inspection apparatus is connected to a rotary machine wherein the inspection apparatus comprises a securing mechanism, in accordance with a second embodiment of the present disclosure; figure 3a is a diagram showing an inspection apparatus for a rotary machine wherein the inspection apparatus comprises computer hardware according to a third embodiment of the present disclosure; figure 3b is a diagram showing an inspection apparatus for a rotary machine, wherein the inspection apparatus comprises computer hardware with a memory storage according to a fourth embodiment of the present disclosure; figure 4 is a flow chart of the inspection process using the inspection apparatus according to a fifth embodiment of the present disclosure; figure 5a is a cross-section side view schematic of a rotary holder releasably coupled to the sensor according to a sixth embodiment of the present disclosure; figure 5b is an expanded side view schematic of the rotaiy holder releasably coupled to the sensor according to the sixth embodiment of the present disclosure; figure 5c is a top view schematic of the rotary holder releasable coupled to the sensor according to the sixth embodiment of the present disclosure; figure 5d is cross section side view schematic of the rotary holder decoupled from the sensor according to the sixth embodiment of the present disclosure; figure 5e is an expanded side view schematic of the rotary holder decoupled from the sensor according to the present embodiment of the present disclosure; and figure 5f is a top view schematic of the rotary holder decoupled from the sensor according to the sixth embodiment of the present disclosure. DETAILED DESCRIPTION The following text will refer to rotaiy machines and inspection; therefore, a general definition is now provided for rotaiy machines. Rotary machines may comprise milling, mill-turn, grinding machines, drill machines or lathe machines arranged to perform various machining operations using one or more machine tools arranged for cutting, grinding, drilling, and / or milling for example. Figure la is a schematic of a known rotaiy machine 100 configured as a lathe. In this example, the known rotary machine 100 configured as the lathe, is a type of machine tool that rotates a workpiece (not shown] about an axial axis of rotation 116 (Z axis) to create a finished object with symmetry about the axial axis of rotation 116. The primary function of the rotary machine 100 is to remove material from a rotating workpiece, which allows it to achieve the desired shape and dimensions. The rotary machine 100 may have a drive housing 102 which is a stationary part of the rotary machine 100 and houses an internal driving mechanism that provides a torque. The rotary machine 100 may have a rotary component 104 that rotates about the axial of rotation of 116. The rotary component 104 coupled to the driving mechanism and receiving the torque. The rotary component 104 may have a spindle 106 located within drive housing 102. The spindle 106 may house one or more spindle bearings to assist with stable rotation. The rotary assembly 104 may have a rotary holder 108 (in the case of a lathe known as a chuck) which may be coupled to the spindle 106 and in the present example of the lathe, holds the workpiece in place while rotating during machining operations. For milling, the rotary holder 108 may hold a cutting tool as described in Figure lb. The rotary assembly 104 may have a drawbar arrangement 118 contained within the spindle 106. The drawbar arrangement 118 may have a drawbar and one or more internal drawbar bearings (not shown). The drawbar arrangement 118 is configured to hold the rotary holder 108 securely to the spindle 106 during rotation. The rotary machine 100 may have a primary holder 110 which may in the present example hold a cutting tool for turning machine operations such as radial work on the workpiece in rotation, such as cutting or grinding an outer diameter of the workpiece, for milling, the secondary holder (tailstock) 112 may hold the workpiece. The rotary machine 100 may have an adjustable stock 111 (in the case of a lathe known as a carriage), coupled to the primary holder 110 and configured to reposition the primary holder 110 to perform machining operations. The rotary machine 100 may have a tailstock 112, which can be used to hold the workpiece and mount a secondary holder for a cutting tool to perform axial work on the workpiece, such as drilling or milling. The rotary machine 100 may have a base 114, which provides support and foundation for the rotary machine 100. In this example of the rotary machine 100 configured as a lathe, the rotary component 104 rotates the rotary holder 108 thereby rotating the workpiece secured to the rotary holder 108. Machining work is then performed on the workpiece by the primary and secondary holder 110 and / or tailstock 112 with the mounted cutting tool. The rotary machine 100, 100' can vary significantly in size and complexity, from simple manual lathes as illustrated in Figure la, to the mill illustrated in Figure lb (discussed later), to sophisticated computer numerical control (CNC) machines operating on a plurality of axis of rotation. Manual lathes require the operator to manually control the cutting tools, feeds, and speeds. In contrast, CNC lathes automate these processes using pre-programmed machine control sequences, enhancing precision, repeatability, and efficiency in manufacturing. In other examples, this may be dedicated drills, mills and grinders. Figure lb is a schematic of a known rotary machine 100’ configured as a milling machine. The rotary machine 100' arranged as a milling machine may comprise some of the components listed from the rotary machine 100 described previously, therefore the same reference numerals have been used. Specifically, the rotary machine 100’ may have the drive housing 102, the rotary assembly 104, the rotary holder 110 (tool holder), the work piece holder 108 (machining bed), the adjustable stock 111 and the base 114. In the present example, figure lb illustrates the rotary machine 100’ having the rotary holder 108 holding the cutting tool 120. For example, the rotary machine 100’ arranged as the mill, the rotary component 104 rotates the rotary holder 108 with the mounted cutting tool 120. The workpiece is non-rotating when secured to the work piece holder (machining bed) 110. Machining work is then performed on the workpiece by the rotating cutting tool 120. An example is now provided of a current practice of monitoring the rotary assembly 104 health requires periodic checks, such as a drawbar force measurement check or a spindle run-out check. The drawbar force measurement refers to the process of evaluating a clamping force exerted by the drawbar arrangement 118 on the rotary assembly 104. The clamping force of the drawbar arrangement 118 is crucial for maintaining the positional accuracy and stability of the tool during machining operations, directly impacting the quality of the machined parts and the overall performance of the rotary machine 100. Over time, the drawbar arrangement 118 can experience wear or mechanical fatigue to the drawbar and / or bearings leading to a decrease in the clamping force and the reduction can result in tool slippage or vibration, adversely affecting machining accuracy, surface finish, and potentially causing tool breakage. Therefore, regular drawbar force measurements are performed to ensure that the drawbar arrangement 118 maintains adequate clamping force to hold the tool securely under operational loads. The draw bar measurement is typically performed using a drawbar force gauge and a tester, where the tester is inserted into the spindle 106 where it simulates the rotary holder 108. When activated, the machine's drawbar arrangement 118 clamps onto the gauge, and the gauge measures the force applied by the drawbar arrangement 118. The results are then compared against the rotary machine 100, 100’ manufacturer's pre-set specifications for the required clamping force. If the measured force is below the recommended level, maintenance or adjustment may be required to restore the drawbar arrangement's (118) performance. Another method of measuring the health of the rotary components 104 is a spindle run out test. For example, during spindle run out test, a precise deflection measuring instrument, such as a dial indicator or an electronic probe, is placed in contact with the spindle 106 and / or work piece holder 110 and / or rotary holder 108. During the spindle run out test, the rotary machine 100, 100’ is rotated, and the measurement tool records the amount of run-out, a deviation measurement indicating how much the spindle 106 and / or rotary holder 108 deviates from a perfect rotation. Measurements are typically taken at multiple points along the spindle 106 and / or rotary holder 108 to ensure comprehensive assessment. The results of the spindle run-out test are compared against the spindle 100, 100’ manufacturer's pre-set specifications for allowable run-out, which vary depending on the machine's intended use and precision level. If the run-out exceeds these specifications, corrective actions may include spindle repair, realignment, bearing replacement, or other maintenance procedures to restore the spindle 106 to its proper operational condition. Due to the nature of these specific tests, drawbar force and spindle run-out, the dynamic characteristics such as natural frequency, stiffness and damping properties of the rotary machines 100,100’ under test are not measured. If there are variations in these characteristics, the rotary machine 100,100’ will not be able to perform the operations with the historical quality and productivity levels, therefore there is no solution that can inform operators and manufacturers before wear to the bearings impacts on the performance of spindle 106 of the machine. The rotary machine 100,100’ may have a predetermined reference frame for an X reference plane and a Y reference plane. For example, the rotary assembly 1104 may be rotatably aligned to a first position such that a planar surface of the rotary holder 108 may be oriented to be parallel with the X reference, then the rotary assembly 104 may be rotatably aligned to a second position such that a planar surface of the rotary holder 108 may be oriented to be parallel with the Y reference plane. The methodology in which the dynamic characteristics of a rotary assembly 104 is determined involves an impact strike test performed along the X and Y coordinate frames which are orthogonal to the Z axis 116. Figure 2a is a diagram of an inspection apparatus 200 for the rotary machine 100, 100' comprising a rotary assembly 104 in accordance with a first embodiment of the present disclosure. The rotary machine 100, 100’ may have rotatory assembly 104 comprising the spindle 106 and drawbar arrangement 118 as previously described. The inspection apparatus 200 comprises a rotary holder 500 and a sensor 202 which may be coupled to the drawbar arrangement 118. The sensor 202 is configured to monitor a property of the rotary holder 500 in response to an impact strike test. The property may be a velocity and / or an acceleration value and / or a displacement value. The sensor 202 functionality may be provided by an accelerometer, a laser vibrometer or a displacement transducer. Wherein an accelerometer is a device designed to measure acceleration, as known in the art. A displacement transducer is a device that measures a positional displacement value of the rotary machine 100, 100’ relative to any frame of reference. A laser vibrometer utilises the principles of laser interferometry and beam forming well known to those in art to achieve precise and accurate deflection measurements. The inspection apparatus 200 may be used to facilitate a repeatable implementation of impact strike testing by providing an embedded sensor 202 and a flat surface with strike position indicator on its opposite side for impact hammer strike. During an impact strike test, an impact force is applied to the rotary holder 500 which is done using a specialised instrument such as an impact hammer. This impact causes the system to vibrate at many frequencies including its natural frequencies. The sensor 202 is used to measure the rotary machine's 100, 100' response to the impact strike at the location where the sensor 202 is attached. The data collected from the sensor 202 may be analysed to identify a frequency response function (FRF), which graphically represents the rotary machines 100, 100’ response across a range of frequencies. In other words, frequency response function refers to the characteristic vibration or oscillation that a material or mechanical system exhibits when subject to an impact, such as from a strike impact hammer (not shown). This response is specific to a rotary machine 100, rotary assembly 104 and rotary holder 500. The frequency response function is identified by comparing responses measured from sensor 202 and from the strike impact hammer (not shown) in the frequency spectrum within data processor 302. The frequency response function reveals information about the rotary machine 100,100’ dynamic properties, including: i) resonant frequencies; frequencies at which the rotary machine 100,100’ naturally prefers to oscillate. At these frequencies, even small forces can produce relatively larger vibration amplitudes due to resonance. ii) damping characteristics, the ability of rotary machines to dissipate energy, affecting how quickly the vibrations diminish after the initial impact. Figure 2b is a diagram of an inspection apparatus 200 for a rotary machine 100,100’, wherein the inspection apparatus 200 comprises a securing mechanism 204, according to a second embodiment of the present disclosure. The inspection apparatus 200 is the same as the inspection apparatus 200 of Figure 2a with the addition of the feature of the securing mechanism 204 that provides selective coupling to the rotary assembly 104. Hence, the same labelling has been kept and the components are taken to have the same functionality and meaning as for the inspection apparatus 200 of Figure 2a. The sensor 202 may comprise the securing mechanism 204 that is configured to provide a releasable coupling to the rotary assembly 104, which may be coupled directly to the rotary holder 500. The securing mechanism 204 may be provided by any selectively releasable fastening device, such as a threaded connection, a quick connect and release compression fitting or a clamping mechanism. The rotary holder 500 may be coupled to the rotary assembly 104 during an inspection impact strike test that elicits a frequency response. After the test is performed the rotary holder 500 may be decoupled from the rotary assembly 104 for regular machine operations. Figure 3a is a diagram of an inspection apparatus 200 comprising computer hardware 306 for a rotary machine 100, 100’ according to a third embodiment of the present disclosure. The inspection apparatus 200 is the same as the inspection apparatus 200 of Figure 2b with the addition of the feature of the computer hardware 306. Hence, the same labelling has been kept and the components are taken to have the same functionality and meaning as for the inspection apparatus of Figure 2b. The computer hardware 306, further comprises an Analogue to Digital converter (ADC) - not shown, as well as a data processor 302. The computer hardware 306 may be embedded within the inspection apparatus 200 or may be coupled wired and / or wirelessly, such that it is configured as a remote cloud-based server connected wirelessly to the inspection apparatus 200. For example, the wireless coupling may be a blue-tooth, wireless fidelity (WI-FI), loRaWAN, radio or cellular connection. The computer hardware 306 has functionality may be provided by a microprocessor (not shown). The computer hardware 306 may receive an inspection signal from the strike impact hammer (not shown) as well as the sensor 202 carrying information of the property of the rotary machine 100, 100’. The inspection signal from the strike impact hammer (not shown) may comprise of force value whereas the inspection signal from the sensor 202 may comprise information of the velocity and / or an acceleration value and / or a displacement value. The computer hardware 306 may be configured to receive both inspection signals and determine the rotary machine’s (100) compliance to a predetermined inspection criterion. The computer hardware 306, using the ADC (not shown) may derive a frequency response from inspection signals, such as a force impact and / or a vibration response. For one example the computer hardware 306 may provide any of the following functionality: 1. Data Collection The ADC (not shown) of the computer hardware 306 may receive information from the sensor 202 that measures the voltage representation of properties such as acceleration, velocity or displacement previously described, over time, of the rotary machine 100, 100’ being analysed. This time-domain data captures how the property varies, reflecting information about the rotary machine 100,100’ and / or the strike impact hammer dynamic behaviour in response to the strike impact test using a strike impact hammer. Wherein the Digital Converter (ADC) converts the analogue sensor signal into a digital form for processing by the data processor 302 within the computer hardware 306. The data processor 302 may be within the sensor 202 (not shown) working wirelessly or maybe within a standalone hardware such as computing hardware 306 that needs a wired connection to the sensor 202. 2. Signal Conditioning Before analysis, the inspection signal may require conditioning to improve its quality and relevance, which may be performed using the ADC (not shown) and / or data processor 302: i) Filtering may remove noise and irrelevant frequencies from the signal, isolating the meaningful data. ii) Amplification may adjust the signal level to a suitable range for processing and convert the signal level to an acceleration, velocity or displacement property. Wherein the data processor 302 of the computer hardware 306 performs the following steps: 3. Fast Fourier Transform (FFT) Fast Fourier Transform (FFT) is an algorithm that transforms the time-domain signal into the frequency domain: The FFT is a mathematical transformation that decomposes the time-domain of the property data into its constituent frequencies, providing a spectrum that shows the amplitude of vibrations at different frequencies. The FFT of the vibration response and the impact signals are analysed to understand their dynamic vibration behaviour over a frequency spectrum. 4. Frequency Response Function (FRF) Analysis: A Frequency Response Function (FRF) is the relationship between the excitation and the vibration response of a structure in a frequency domain. The FRF can be derived by dividing the FFT of the acceleration and / or velocity and / or displacement signals by the FFT of the impact force. In particular, receptance FRF is of interest for this present disclosure which is obtained by dividing acceleration, velocity and or displacement response by force impact response in the frequency domain. The data processor 302 of the computer hardware 306 identifies the FRFs and hence frequencies at which the rotary machine 100, 100' exhibits significant responses, such as peaks in the spectrum, which represent natural resonant frequencies or modes of vibration. For each frequency, the data processor 302 may calculate the FRF which constitutes the magnitude (the strength or amplitude of the response) and the phase shift (the difference in phase between the input excitation and the rotary machine 100,100’ response). 5. Interpretation and Application The calculated FRF provides insights into the dynamic properties of the rotary machine 100,100' under test, such as stiffness, mass and damping. The FRF can be used to assess the health of the rotary assembly 104 (specifically spindle 106 and the bearings holding the drawbar 118) and its compliance with a predetermined inspection criterion. The inspection process is explained in further detail below with reference to Figure 4. 6. Output and Reporting The computer hardware 306 containing data processor 302 outputs the calculated frequency response function (FRF) in a form suitable for further analysis, monitoring, or decision-making, such as graphs or numerical reports. The data processor 302 may output a notification of a need for a physical check to review the health of rotary assembly 104 based on the analysis. For example, the result of the physical check may be to carry out maintenance and / or replace the spindle 106 and / or any internal component such as the spindle bearings after a defined number of operational cycles. For example, the notification may indicate a current health status of the spindle bearings and predicate an approximate life time remaining for the spindle bearings and alerting that spindle bearings have reach a critical condition threshold wherein the critical condition threshold is indicative that the spindle bearings may deteriorate rapidly. Figure 3b is a diagram of an inspection apparatus 200 connected to computer hardware 306 with memory storage 304 and a data processor 302 according to a fourth embodiment of the present disclosure. The inspection apparatus 200 is the same as the inspection apparatus 200 of Figure 3a with the addition of the computer hardware 306 comprising a data processor 302 and memory storage 304. Hence, the same labelling has been kept and the components are taken to have the same functionality and meaning as for the inspection apparatus of Figure 3a. The data processor 302 and the memory storage 304 are configured to log the frequency response function determined by the data processor 302. The data processor 302 and the memory storage 304 may perform the handling of the logging, retrieval, and manipulation of data by memory resources, such as RAM (Random Access Memory], cache, or other types of volatile or non-volatile memory. Figure 4 is a flow diagram of the inspection process 400 using the inspection apparatus 200 according to a fifth embodiment of the present disclosure. The inspection process 400 may comprise any of the following steps: Step 1.1 [Sia] 402 Coupling the inspection apparatus 200 with the rotary assembly 104. For example, this may be performed by clamping the inspection apparatus 200 with the drawbar arrangement 118 to ensure a rigid and stable connection. Connecting the sensor 202 to the data processor 302 of the computing hardware 306. . For example, the connection between the data processor 302 and the computing hardware 306 may be performed by a communication cable, such as a universal serial bus, or the connection is made wirelessly, or on-chip. Step 2 (S2) 404 Exciting the inspection apparatus 200 with a strike impact hammer in a X direction. The X direction is a strike vector of the strike impact hammer along the X reference frame of the rotary machine 100,100'. The inspection apparatus 200 should be rotated such that the planar surface for an impact strike test performed by strike impact hammer is orthogonal to the X direction so that the strike impact test and exerted force is aligned with the X reference frame of the rotary machine 100,100’. Step 3 (S3) 406 The sensor 202 records the property values, thereby enabling calculation of the FRF in the X direction based on excitation generated from a suitable number of consistent impact strikes in X direction. Step 4 (S4) 408 Step 2 and step 3 are repeated, with an exception that is now performed in a Y direction. The Y direction is the strike vector of the strike impact hammer along the Y reference frame of the rotary machine 100,100’. Step 5 (S5) 410 Transmission of the inspection signals of the property recorded by the sensor 202 plus that of the strike impact hammer to the data processor 302. Logging the test FRF within the memory storage 304 of the data processor 302 in response to identification of the test FRF. The data processor 302 may identify anomalies in the FRF that are logged at this time. An anomaly may be: i) an unexpected peak or dip, such as sudden peaks or dips in the frequency response function (FRF) that do not align with the previously measured profiles of the rotary machine 100,100’; ii) a shift in a resonant frequencies or response curves such as changes in the frequencies or response curve at which the rotary machine 100,100’ exhibits resonant behaviour, compared to what is expected based on the rotary machines 100, 100’ physical characteristics, historical FRF responses or design specifications; iii) a phase shift such as unanticipated shifts in the phase response of the rotary machine 100,100' at an anomalous frequency range. iv) a damping ratio shift such as the shape of the peaks of the frequency response, such as the peaks pointiness at the natural frequency of the rotary machine 100, 100’. Step 7 (S7) 414 Perform comparative analysis of the under test FRF against historical FRF measurements logged on the data processor 302 with a memory storage 304. The data processor 302 may compare the test FRF or anomalies previously described in the test FRF, against a historical FRF. The historical FRF is not limited to a singular value but may be a dataset comprising a plurality of values. The comparative analysis of the difference between each test FRF and the relevant historical FRF may be used to generate a variation value. Step 8 (S8) 416 Predict the health status of the rotary assembly 104. This may be performed by comparing the variation value with a pass tolerance value. The pass value may be a range, where if the variation value falls within the range of the pass tolerance value the inspection criteria is passed, and if the variation value falls without the range of the pass tolerance value, then the inspection criteria is failed. S8 416 may utilise a machine learning algorithm implemented on the data processor 302 which makes predictions as to the future characteristics of the rotary machine 100, 100’. For example, the machine learning algorithm may perform regression analysis on the FRF logged on the data processor 302, thereby predicting the life expectancy of the rotary component, thereby predicting the future health of rotary assembly 104. Figure 5a is a cross-section side view schematic of the inspection apparatus 200 which is a rotary holder 500 releasable coupled to the sensor 202 according to a sixth embodiment of the present disclosure. The rotary holder 500 may share any characteristics of the rotary holder 108 previously discussed when adapted for a mill. The rotary holder 500 may share any characteristics of the rotary holder 108 previously discussed when adapted for a lathe. The rotary holder 500 comprises an outer profile 502 and an internal profile 504. For example, the outer profile 502 may conform to a cylindrical outer radial perimeter and internal profile 504 may conform to an internal radial perimeter. The rotary holder 500 may have a mating connection 506 that mates with the securing mechanism 204 of the sensor 202. For example, the mating connection 506 may be a box thread connection that mates with a pin thread connection of the securing mechanism 204. The rotary holder 500 may comprise a strike surface 508. The strike surface 508 may be the planar surface described previously, which is suitable for an impact strike test from a strike impact hammer. In one example, the strike surface 508 may be the machined planar surface of the rotary holder 500 comprising steel. The steel may not be required to be hardened as the force of impact of the hammer strike impact is typically 300N or less. A secondary planar surface 510 which is parallel to the strike surface 508, may be arranged such that it is orthogonal to the thread box connection 506. Figure 5b is an expanded side view schematic of the inspection apparatus 200 comprises the rotary holder 500 releasably coupled to the sensor 202 according to the sixth embodiment of the present disclosure. In this example the sensor 202 comprises a body portion having a dimension A 522 which is a radial diameter of 6.1mm. The securing mechanism 204 comprises a dimension B 520 with an outer diameter of 14mm. Figure 5c is a top view schematic of the inspection apparatus 200 comprises the rotary holder 500 releasably coupled to the sensor 202 according to the sixth embodiment of the present disclosure. Figure 5d is a cross-section side view schematic of the rotary holder 500 which is the inspection apparatus 200 decoupled from the sensor 202 according to the sixth embodiment of the present disclosure. In this example, the rotary holder 500 may comprise a dimension C and a dimension D. The dimension C 540 is an outer radial perimeter of 20mm. The dimension D is a tolerance range of + / - 0.01mm for the depth of the strike surface 508. Figure 5e is an expanded side view schematic of the rotary holder 500 which is the inspection apparatus 200 decoupled from the sensor 202 according to the sixth embodiment of the present disclosure. The rotary holder 500 may comprise a dimension E, a dimension F, a dimension G and a thread specification H. In this example, the dimension E 544 is a box depth of 8.5mm. The dimension F 546 is a thread depth of 8mm. The dimension G 548 is a bore depth of 10.01mm. The thread specification H is M6xl.00 to a thread depth of 8mm. Figure 5f is a top view schematic of the rotary holder 500 which is the inspection apparatus 200 decoupled from the sensor 202 according to the sixth embodiment of the present disclosure. The rotary holder 500 may comprise a dimension I, a dimension J, a dimension K, a dimension L. In this example, the dimension I 552 is a first length of 33.25mm. The dimension J 554 is the second length of 63.50mm. The dimension K 556 is the receiving insert length of 14.00mm for the securing mechanism 204. The dimension L 544 is the receiving insert radius width of 7.00mm for the securing mechanism 204. The present disclosure advantageously provides the current health status and predicate an approximate life time remaining for the spindle bearings contained in the rotary assembly 104 of rotary machines 100,100’ without the need for physical disassembly and / or inspection, hence saving time and resources. The aim of the disclosure is to deliver an inspection apparatus 200 for monitoring the health of rotary assembly 104 and help manufacturers identify problems with rotary assembly 104 before they start causing problems in production. The inspection apparatus 200 is connected to computing hardware 306 comprising a data processor 302 and memory storage 304. Using hardware and software, operators of the rotary machine 100,100' collect data from the inspection apparatus 200 at regular intervals, such biweekly or monthly, and measurement data may be gathered in a data processor 302 with a memory storage 304 housed within the computer hardware 306. In addition, operators register anomalies observed on the rotary machines 100, 100' during production such as spindle crashes, bearing problems or clamping problems between the rotary holder 108 and the spindle 106. The anomalies are also logged in the memory storage 304 of computing hardware 306. The data processor 302 may contain a machine learning algorithm that correlates measurements variations and event logs during an initial data collection period. In response to the collection of the FRF, the machine learning algorithm may start making predictions about the health of the rotary assembly 104 and categorise the rotary assembly 104 as "Healthy", "Requires attention soon” and "Requires attention now". Periodical maintenance checks are time consuming processes. People that do such measurements in factories are generally busy and they want any measurement to be completed as quickly as possible. Having an embedded sensor 202 on the rotary holder 108 makes the users jobs quite easy and quick. The inspection apparatus 200 maximises the chance of repeatable and consistent data acquisition by ensuring that the sensor is positioned in the same location on the inspection apparatus 200 rotary machine 100,100’ and that the impact zone is simple to identify, and physically easy to strike repeatedly in the same place, beneficially providing consistent data acquisition environment, in which the impact force applied to the rotary machine 100,100’ is consistently uniform. This has been able to demonstrate inspecting approximately 10 machine tools in less than half an hour.

Claims

1. An inspection apparatus for a rotary machine having a rotary assembly, wherein the inspection apparatus comprises:a sensor, the sensor coupled to the rotary assembly wherein the sensor is configured to monitor a property of the rotary machine in response to an excitation of the rotary assembly from an impact strike test; and wherein the inspection apparatus is configured to enable repeatable and consistent implementation of the impact strike test to derive a frequency response function of the rotary assembly from the property.

2. The inspection apparatus of claim 1 where the sensor comprises:an accelerometer; and / ora displacement transducer; and / ora laser vibrometer.

3. The inspection apparatus of claim 2 wherein the rotary machine comprises:a lathe; and / ora drill; and / ora mill; and / ora mill-turn machine; and / ora grinder.

4. The inspection apparatus of any preceding claim, wherein the rotary assembly comprises:a spindle configured to rotate; anda drawbar arrangement that connects the spindle with rotary holder; anda rotary holder coupled to the spindle and configured to secure a cutting tool and / or a work piece.

5. The inspection apparatus of claim 4, wherein the sensor comprises:a securing mechanism configured to provide a releasable coupling of the sensor to the rotary holder.

6. The inspection apparatus of claims 4 to 5 wherein the property comprises a signal data property comprising;a force value; and / oran acceleration value; and / ora displacement value; and / or a velocity value.

7. The inspection apparatus of claims 4 to 6, wherein impact strike test is configured to be performed by a strike impact hammer.

8. The inspection apparatus of claim 7, wherein the impact strike test comprises:a first set of impact strike tests comprising a test sequence having the steps: one or more first strike test on the rotary holder in a first direction;andone or more second strike tests on the rotary holder in a second direction.

9. The inspection apparatus of claim 8, wherein the sensor is configured to transmit an inspection signal carrying information of the property to a data processor, wherein the data processor is configured to receive the inspection signal and determine the rotary assembly compliance to an inspection criterion.

10. The inspection apparatus of claim 9, wherein the data processor within the computing hardware is configured to process the inspection signal thereby determining a first test frequency response function to the first set of impact striketests.

11. The inspection apparatus of claim 10, wherein the data processor accesses a memory storage configured to log the first test frequency response function.

12. The inspection apparatus of claim 11 wherein the impact strike comprises:a second impact strike test comprising: repeating the test sequence steps.

13. The inspection apparatus of claim 12, wherein the data processor is configured to process the inspection signal from the data processor thereby determining a second test frequency response function to the second impact strike test.

14. The inspection apparatus of claim 13, wherein the memory storage is configured to log the second test frequency response.

15. The inspection apparatus of claim 14, wherein the data processor is configured to provide comparative analysis of the difference between the first test frequency response function and the second test frequency response function thereby generating a variation value compared to their corresponding historic values.

16. The inspection apparatus of claim 15, wherein the data processor is configured to implement a machine learning algorithm where the algorithm identifies the extent of variations within the frequency response function based on the comparative analysis in order to generate and assess against pass tolerance value.

17. The inspection apparatus of claim 16, wherein the machine learning algorithm is configured to perform regression analysis.

18. The inspection apparatus of claim 17, wherein the data processor with a memory storage is configured to store a pass tolerance value.

19. The inspection apparatus of claim 18, wherein the inspection criterion is passed if the variation value is less than or equal to the pass tolerance value otherwise the inspection criteria is failed.

20. The inspection apparatus of any of claims 9 to 19 wherein the transmission of the inspection signal is performed by a wireless connection to a remote server remote computing hardware) and / or wired connection to a computing hardware; and wherein the data processor may be housed within the sensor or may be within a standalone hardware.

21. The rotary holder of claim 20 further comprising:an outer profile configured to provide an outer radial perimeter; andan internal profile configured to provide an internal radial perimeter; and a strike surface arranged on the outer radial perimeter configured to receive the strike impact test.

22. The rotary holder of claim 21 further comprising:a threaded box connection arranged on the outer radial perimeter and configured to receive the sensor of claims 1 to 21, and whereinthe rotary holder of claim 21 arranged such that the threaded box connection is positioned 180 degrees from the opposing strike surface.

23. A method of inspecting a rotary assembly having a spindle and / or a rotary holder comprising the steps of:coupling a sensor to the rotary holder; andperforming a first set of strike impact tests on the rotary assembly and generating a first frequency response function results;performing a second set of strike impact tests on the rotary assembly and generating a second frequency response function results;performing comparative analysis on the first frequency response function and the second frequency response function thereby determining compliance to an inspection criterion.

24. The method of claim 23 further comprising transmitting an inspection signal to computer hardware, the computer hardware comprising a data processor, wherein the is configured to process the inspection signal thereby determining a first test 5 frequency response function to the first set of impact strike tests and second frequency response function to the second set of impact strike tests and performing comparative analysis on the first frequency response function and the second frequency response function thereby determining compliance to an inspection criterion.1025. The method of claim 23 or claim 24 further comprising analysing the variations within the frequency response function based on its historic values and determining the current health status of the rotary assembly by applying machine learning algorithms and predicting future health and its remaining life.15

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