GB2623752A - A metrology and inspection system - Google Patents

Abstract

An automated and intelligent Metrology and Inspection system 1 comprising a rigid base platform 2, at least one detachably mounted multi-axis object clamping unit 4, at least one detachably mounted multi-axis arm positioning unit comprising a measurement and inspection subsystem 5 and a system controller. In addition, a method of measuring and inspecting an object comprising clamping the object to be measured, positioning the object to present a region of interest to a plurality of sensors, positioning at least one of the sensors to measure an attribute in a region of interest, positioning another sensor to measure an attribute in a region of interest, gathering and collating the measurement data from the sensors and communicating the data to a system controller. The system may comprise an in-built verification module for self-calibrating the system using traceable artifacts.

Description

"A Metrology and Inspection System"

Introduction

The invention relates to an automated and intelligent Metrology and Inspection (M&I) system. The M&I system integrates heterogeneous metrology techniques such as contact and non-contact measurement subsystems, uses multiple M&I types, and deploys algorithms to select the appropriate M&I type to measure and inspect the object under test (OUT).

Manufacturing systems used in highly regulated environments such as those used in, for example, the food and drinks industry, pharmaceutical, medical devices, fast moving consumer goods (FMCG), and transport industries, require extremely high precision and high quality M&I systems. M&I systems are typically used to carry out product verification and validation, in-process control, and batch release to provide quality assurance and/or continuous quality control.

Companies operating in highly regulated environments adhere to quality systems which require M&I systems to be capable of producing repeatable and reproducible measurements to identify product defects and out of tolerance features to ensure the product shipped to the customer meets the product quality standards and to avoid the shipping of defective product.

There is a real need in the metrology industry for an improved M&I system which can easily combine different M8EI systems deploying different M&I technologies in a single 25 system.

Statements of Invention

According to the invention there is provided an automated and intelligent Metrology and Inspection system comprising; a rigid base platform; at least one detachably mounted multi-axis object clamping unit; at least one detachably mounted multi-axis arm positioning unit comprising a measurement and inspection subsystem; and a system controller.

In one embodiment of the invention the system comprises an in-built verification module for self-calibrating the metrology system using traceable artefacts.

In one embodiment of the invention the system controller automatically selects a measurement and inspection subsystem to optimise the Metrology and Inspection of an object.

In another embodiment of the system controller provides system learning and adjustment to optimise and automatically tune the measurement process for the object being measured.

In one embodiment of the invention the system controller coordinates the movement and positioning of the object to be measured and inspected using the multi-axis object clamping unit with the measurement and inspection subsystem.

In another embodiment of the invention the clamping system comprises fixtures to clamp the object in its natural state. Preferably the clamping unit fixtures are manufactured from a polymer material.

In one embodiment of the invention the measurement and inspection subsystem comprises surface based and/or sub-surface measurement and inspection sensors. Preferably the sensors are selected from any one or more of a touch probe, image sensor, ultrasound sensor, hybrid probe or computerised tomography module.

In one embodiment of the invention the rigid base platform is a high density rigid anti-vibration material.

In one embodiment of the invention the system is detachably mounted to a conveyance system.

In one embodiment of the invention the automated Metrology and Inspection system comprises a single platform Metrology and Inspection system.

According to the invention there is also provided a method of carrying out non-destructive measurement and inspection of an object comprising a Metrology and Inspection system.

According to the invention there is also provided a method of measuring and inspecting an object comprising the steps; clamping the object to be measured and inspected; positioning the object to present a region of interest to a plurality of measurement and inspection sensors; positioning at least one of the measurement and inspection sensors to measure and inspect an attribute in a region of interest of the object; positioning another measurement sensor to measure and inspect an attribute in a region of interest of the object; gathering and collating the measurement data from the sensors; and communicating the data to a system controller.

In one embodiment of the invention measurement and inspection sensors are selected from any one or more of a touch probe, hybrid probe, image sensor, ultrasound sensor and or computerised tomography module.

In one embodiment of the invention the system controller enables system learning and adjustment to optimise and automatically tune the measurement process for the object being measured. Preferably the system controller comprises an in-built verification module for self-calibrating the metrology system using traceable artefacts. Most preferably the system controller generates a database of product measurement configurations to generate an optimised measurement program for the object to be measured.

In one embodiment of the invention the generated database allows the system to identify and predict time dependent quality attributes of the object at discrete time points throughout the process and according to end use parameters of the object.

In one embodiment of the invention the system automatically adjusts the measurement process in response to any deviation in the required time dependent quality attributes of the object.

In another embodiment of the invention the generated database allows the Metrology and Inspection system to identify and order the quality attributes of an object according to the end use parameters of the object.

In one embodiment of the invention the gathering and collating of the measurement data allows the system to capture-in-line critical quality defects. Preferably the gathering and collating of the measurement data allows the system to monitor and control process drift and provide feedback to manufacturing systems in-line to make the required adjustments to control any deviation in process drift. Most preferably the gathering and collating of the measurement data allows the system to predict process failure and pre-empt maintenance issues.

In one embodiment of the invention the system controller reduces overall production cycle time through multiple and parallel measurements and inspections on different features of the object.

Brief Description of the Invention

The invention will be more clearly understood from the following description thereof with reference to the accompanying drawings in which: -Fig. 1 is a schematic of the M&I system of the invention as a standalone system for sampled measurements; Fig. 2 is a schematic view of the M&I system of Fig. 1 mounted on a conveyance transfer system and deploying multiple contact measurement subsystems.

Fig. 3 is a further schematic of the M&I system of Fig. 1 mounted on a conveyance transfer system showing different M&I technologies and deploying both contact and non-contact M&I technologies; Fig. 4 is a schematic of the M&I system of Fig. 3 and its connection to a system controller comprising a computerised system and a data storage device; Fig. 5 is a schematic plan view of the Mail device of the invention integrated with a conveyance transfer system; Fig. 6 is a schematic of a sample medical syringe which can be inspected using the M&I system of the invention; Fig. 7 is a schematic of an inhaler device (a) being inspected using the M&I device of the invention integrated with a conveyance transfer system (b); Fig. 8 is a schematic of an Internal component of an auto injector device (a) being inspected using the M&I device of the invention integrated with a conveyance transfer system (b); Fig. 9A is a graph showing output of a single sensor of the M&I system with the output producing an indeterminate acceptance threshold between a rejectable artefact and an acceptable artefact; Fig. 9B is a schematic showing a combination of multiple sensor outputs with and without sensor setting adjustments to produce higher resolution M&I output; Fig. 9C is a graph showing the self-tuning of the M&I system to provide higher resolution M&I output enabling the setting of acceptance thresholds to deterministically distinguish between rejectable artefacts and acceptable artefacts; Fig. 10A is a graph showing total serialised M&I cycle time for a total quantity of "L" features with the M&I self-tuned procedure implementing a total quantity "N" sensors; Fig. 10B is a graph showing an optimised M&I sequence reconfigured for the serialised sequence of Fig. 10A such that the sensors S2 and SN are deployed to carry out M&I on other features in parallel to reduce the overall cycle time; Fig. 11A is a graph showing a quality parameter for an OUT measured with the M&I system of the present invention immediately post production, at time periods one hour, two hours and three hours post production, and at the end of a stability period where further changes in quality parameters are negligible; Fig. 11B is a graph showing the effects of process drift on a quality parameter whereby the quality parameter remains within specification (within the USL and LSL) immediately post production and for several hours after production, before the quality parameter goes out of specification resulting in a defective component after the OUT has fully stabilised; Fig. 11C is a graph showing time dependent control limits calculated by the M&I system to enable the M&I system to correct process drift using M&I of the OUT at any time post production; and Fig. 12 is a flow chart showing the M&I steps taken using the M&I system of the invention.

Detailed description

Product quality can depend on a variety of different product parameters and different product parameters are better suited to certain metrology techniques more so than others. For example, certain dimensional measurements may be suited to contact measurements using a coordinate measurement machine (CMM) touch probe whereas other dimensional measurements may be better suited to optical measurements.

As a further example, sub surface defects such as sub surface cracking, voids, and porosity cannot be detected using surface based contact or conventional optical non-contact inspection techniques and require non-destructive inspection using within domain inspection techniques. Methods suitable for carrying out such non-destructive within domain inspection include X-ray, computerised tomography, and/or ultrasound.

The selection of an M&I system for product M&I is typically based on the experience and "rule of thumb" of the product and M&I system designers. The optimum selection of an Mg.1 system will depend on the metrology and inspection technology best suited to optimising multiple factors such as measurement precision and accuracy for the parameters under test, cycle time of the M&I system and criticality of the parameter under test. For example, if the parameter directly relates to the critical life-saving functionality of a medical device, e.g. balloon wall thickness in a balloon catheter for treating vascular disease, touch probe technology may be superior to optical inspection methods.

Typically, M&1 systems deploy a single M8.1.1 technology, such as contact probe measurement in a CMM, image sensors in an optical measurement system, X-Ray modules in a computerised tomography (CT) scanner. However, product quality assurance and quality control require the M&I of multiple component attributes, which in turn require multiple M&I technologies. Therefore, manufacturers are required to deploy multiple independent M&I systems to carry out product quality assurance and quality control resulting in inefficiencies due to the large footprint of multiple M&I systems and increased cycle times due to handling and transfer of the Object under Test (OUT) between the multiple M&I systems.

The M&I system of the present invention integrates multiple M&1 technologies into a single platform and provides an M&I system controller to automatically select a combination of M&Itechnologies to carry out optimised M&Iaccording to the type of product and test conditions. Having a single platform with multiple M&1 technology capabilities enables a reduction in the footprint for M&I compared to a test system arrangement combining multiple individuals M&I systems each of which is dedicated to a single M&I technology. Furthermore, a single platform with multiple M&1 technology capabilities reduces the part handling and part transfer steps when compared with that for the combination of multiple single standalone M8Eltechnology systems.

Figs. 1 to 5 illustrate various embodiments of the automated and intelligent M&I system of the present invention with a syringe 10 shown as a non-limiting embodiment of the OUT. In Fig. 2, the M&1 system comprises an object clamping subsystem 4 with fixtures 7 to clamp the OUT. The object clamping subsystem 4 presents regions of interest on or in the OUT to a plurality of M&I subsystems 5.

The object clamping subsystem 4 and the plurality of the M&I subsystems 5 are mounted on solid rigid base 2, which isolates the object clamping subsystem 4 and the plurality of the M&I subsystems 5 from environmental vibrations to enhance the overall accuracy and precision of the M&I system. The solid rigid base 2 may be manufactured from a high density rigid material such as granite, steel or the like, which eliminate the transmission of vibrations to the M&I subsystems and the OUT. In addition, the solid rigid base 2 provides an anti-vibration platform for mounting a conveyance transfer system 3 as shown in Fig. 2.

The object clamping unit 4 and the plurality of M&I subsystems 5 can implement a variety of positioning technologies depending on the quantity and complexity of the features for M&I. To illustrate by means of some examples, if the OUT requires M&I for a small number of external features, single axis linear or rotary positioning systems provide sufficient capability for positioning the object clamping subsystem 4 and the plurality of M&I subsystems 5. However, if the OUT requires M&I for a larger number of internal and external features, then a multi-axis robotic positioning system is required to provide sufficient capability for positioning the object clamping subsystem 4 and the plurality of M&I subsystems 5.

Each M&I subsystem 5 supports at least one sensor 16. The sensor 16 may comprise sensors such as CMM touch probes, optical sensors, X-ray devices, CT devices, ultrasound scanners or the like. Fig. 2 shows two M&I subsystems 5 each of which supports a touch probe 16. This multiple M&I subsystem arrangement advantageously enables parallel Mad for different features of the OUT, thereby reducing the overall cycle time of the M&I procedure for the OUT. Furthermore, additional M&I subsystems can be implemented to increase the level of parallel M&I for further cycle time reduction.

Fig. 3 shows an alternative embodiment of the M&I system comprising two M&I subsystems 5, one of which supports a touch probe 16 and the other supporting an optical system comprising an image sensor 17 with a lens and optical sensor enabling optical inspection of the OUT 10. With this arrangement, the M&I system provides enhanced precision for the M&I procedure with the provision of heterogeneous methods to increase the certainty of the quality assessments for the features subjected to M&I. This embodiment can also provide cycle time reduction through parallel M&I for different features of the OUT.

The M&I subsystems are modular and detachable to enable the M&I system to be set up with different sensor configurations according to the requirements of the quality assessment and the properties of the OUT. As an example, the M&I system configured with multiple optical sensors to carry out high speed quality assessments for high volume low cost components can be reconfigured to carry out high precision M&I for safety critical components by replacing the optical sensors with alternate sensors capable of higher precision M&I.

Figs. 2 to 5 illustrate the M&I system mounted on a conveyance transfer system, which is selected from any of the well-known technologies in the field of manufacturing such as belt and pulley arrangements, rotary carousel systems, shuttle systems, pallet systems, robotic transfer systems, and the like. The conveyance transfer system 3 transports the OUT 10 over the solid rigid base 2 to the object clamping unit 4, which picks the OUT 10 from the conveyance transfer system 3 and presents the OUT to the M&I subsystems 5.

In an alternative embodiment, the M&I subsystems 5, carry out the M&I procedure with the OUT 10 remaining in-situ in the conveyance transfer system. This arrangement is particularly suitable when all the features requiring M&I are accessible to the M&I subsystems 5 without requiring the repositioning of the OUT 10.

Any other suitable means may be used to transport the OUT 10 to the M&I system 1. For example, instead of a conveyance transfer system, a pick and place robot may be used to present the OUT 10 to the M&I system 1. Alternatively, the OUT 10 may be transported manually to the M&I system 1.

The selection of the object clamping unit 4 will depend on the materials and geometries of the OUT 10. One important aspect of the object clamping unit 4 is that it does not alter the dimensions or the geometry of the OUT 10. For the M&I system 1, the object clamping unit 4 presents the OUT in its natural state. This is achieved by selecting an appropriate material for the clamping fixtures 7, especially at the object clamping contact points.

The clamping fixtures 7 may be manufactured from any suitable polymer or non-polymer materials. The clamping fixture material is selected based on the elastic properties, rigidity and ability to return to position after flexing of the OUT. Optimal selection of the clamping fixture material ensures the consistent clamping of the OUT for M&I and eliminates the need for over clamping, which can alter the OUT geometry and introduce inaccuracies in the M&I results.

Clamping at optimal positions on the OUT 10 is another critical consideration for maintaining the natural state of the OUT 10. For example, clamping on thicker sections of the OUT with an optimal contact pressure at the clamping contact points is preferable to clamping at thinner sections. Unlike thinner sections, clamping contact pressure can be more readily optimised for thicker sections to ensure the OUT is clamped sufficiently to avoid vibrations or slippage of the OUT while also reducing or eliminating deformation of the OUT due to the clamping contact pressure. However, the clamping position on the OUT 10 must also be optimised to avoid preventing M&I for a feature which becomes occluded due to the clamping by the object clamping unit 4 itself.

As the object clamping unit 4 is a modular subsystem, the M&I system 1 can select and attach different clamping technologies onto the object clamping unit 4 optimised for clamping the particular OUT undergoing the M&I procedure.

A further critical aspect of the OUT clamping unit 4 is the capability to position and orient the OUT to present specific features for M&I to the M&I subsystems 5. Such features are those which are occluded when the OUT 10 is transported to the M&I system or any features which are inaccessible to the M&I subsystems 5. The capability of the OUT clamping subsystem to position and orient the OUT 10 is achieved using technologies ranging from relatively simple linear or rotary motor systems to more complex multi-axis robotic systems.

The M&I system of the present invention integrates multiple metrology and inspection technologies into a single platform providing an ideal means to accurately and efficiently measure and inspect a large variety of products.

Figs 6 to 8 illustrate some typical components requiring high quality M&I. Fig. 6 illustrates a syringe 10 comprising a barrel section 11, a gripping flange 12, a nozzle section 13 with threads 14 positioned on the outer surface of the nozzle section 13 for needle attachment. The nozzle section 13 will typically conform to the Luer taper requirements specified in ISO 80369-7 or the like.

Edge surfaces on the syringe such as the end of the nozzle 13 and the outer edges of the gripping flange 12 are well suited for identification by the optical sensors with appropriate lighting arrangements, hence calculation of quality parameters such as the length of the syringe are ideally suited for an optical M&I system. Other features such as nozzle thread height and inner diameter of the syringe may not be well suited for an optical M&I system if the edges of the features are less apparent as in the case of nozzle thread height and/or if the feature itself is obscured as in the case of the inner diameter. Hence, in order to establish that the syringe meets the required quality criteria thresholds product testing must implement multiple M&I technologies.

Fig. 7 illustrates an inhaler device which benefits from the M&I system comprising multiple M&I technologies. Both the internal and external features of the device can be subjected to multiple M&I technologies using the system of the present invention.

Fig. 8 illustrates an internal component of an autoinjector device, another example of a component which benefits from the M&I system comprising multiple M&I technologies of the present invention. Dimensions such as overall height and overall thickness relating to reference points on the external surfaces of the autoinjector component can be determined by optical M&I techniques. In contrast, dimensions relating to reference points on the internal surfaces, which are obscured from external viewpoints are better suited to contact M&I techniques provided there are pathways from the exterior of the component that enable the contact measurement probes access to the interior surfaces of the component. In situations where access to the interior surfaces is not possible, the M&I system selects a through thickness M&I technology such as ultrasonic or CT scanning to carry out M&I for internal features.

In addition, for a component such as in an a utoinjector device, which must withstand high stresses throughout its in-use lifetime, determination of further quality parameters relating to the component's structural integrity is required to fully complete the quality assessment of the component. In this case, the M&I system of the invention selects the ultrasonic and/or CT scanner M&I subsystem to carry out an assessment of the structural integrity of the component by determining the presence or absence of sub-surface defects such as porosity, voids, sub-surface cracking and similar material defects. Hence, the M&I system provides domain level quality attributes in addition to the surface level quality attributes completing a comprehensive quality assessment of the component.

Fig. 4 illustrates the embodiment of the M&I system 1 shown in Figs. 1 to 3 in which the M&I system 1 is communicatively coupled to a system controller 20, comprising a computer 22 with data processing capability and a display, and/or a data storage device 24 for storage of M&I setup data, programs and results. The communicative coupling may be implemented through a wired physical connection 26, for example, twisted pair, coaxial cable, fibre optic, or through a wireless connection deployed by means of short range or long range wireless technologies. For the purposes of data transfer, standard communication protocols such as physical Ethernet or USB in the case of a wired connection or, 802.11 WiFi or Bluetooth in the case of wired connection is implemented. Fig. 4 illustrates an individual direct data connection for each of the M&I subsystems 5 connecting directly to the computer 22. In an alternative embodiment, the individual M&I subsystems 5 connect to the computer 13' via a communication hub such as a switch or modem which transfers the data inputs and outputs to and from the individual M&I subsystems through a serial link connecting the communication hub to the computer 22.

The computer 22 for the M&I controller may be implemented using an off the shelf general purpose computer with standard data processing capabilities for the M&I of relatively simple components using a limited number of M&I subsystems 5 with simple low resolution sensors involving low data rates. For more complex components requiring multiple M&I subsystems with higher resolution sensors involving higher data rates, the computer 22 requires higher data processing capabilities implemented through more powerful single processor or multi-processor computing systems.

The data storage device 24 storing M&I setup data, programs and results may be implemented using standard data storage technologies such as non-volatile SSD hard drives integrated into the computer 22 or using a separate specific high volume data storage systems such as on-premises factory enterprise systems or cloud server systems. Dynamic real time M&I data such as the position and orientation control instructions for the object clamping unit 4 and M&I subsystem, 5, M&I event triggers such as M&I data acquisition events and the M&I data acquisition itself requires the use of the high speed volatile or non-volatile memory in the computer 22. The M&I controller 20 transfers M&I data from the high speed volatile or non-volatile memory of the computer 22 to the data storage device 24 using event driven triggers generated by the M&I system 1, for example, event triggers to signal the completion of the M&I procedure.

The M&I system controller 20 use set up and calibration data to configure and control the various M&I system modules. For example, position and orientation control of the object clamping units 4 and the M&I subsystems 5 is implemented through the use of static reference points such as static home positions and/or object recognition to identify spatially distributed fiducials or the like in order to register the individual coordinate frameworks for the various system modules and enable precision relative movement and control between the various system modules. As a further example of the use of set up and calibration data, the M&I system loads light intensity and sensor integration time settings to the optical system 17 to ensure optimum optical image acquisition.

The M&I system controller 20 generates M&I programs according to the features and quality requirements of the OUT by analysing the corresponding product data resources made available in the product design databases such as design input requirements files, CAD drawings, risk management files, manufacturing execution systems (MES) and the like. The product data resources may be stored local to the M84.1 system controller 20 in the data storage device 24 or in high volume data storage systems such as on premises factory enterprise systems or cloud server systems or through a combination of both local and remote data storage systems. In order to connect to the remote data storage systems, the M&I system controller 20 accesses the factory network using a wired connection such as physical Ethernet or using a wireless connection such as 802.11 WiFi or Bluetooth or a combination of both wired and wireless connections.

The M&I system controller 20 identifies, catalogues and sorts the product features according to each feature's criticality to quality in accordance with the information contained in the product design databases. Examples of critical to quality features include product features identified in design input requirements files as having a safety impact, thin or complex geometrical features in CAD drawings, high severity and/or high risk features in risk management files, high cost features according to the MES, and the like. The M&I system prioritises these critical to quality features for higher precision M&I.

The M&I system controller 20 selects the most suitable M&I sensor type for the critical to quality features according to a feature classifier which stores feature classifications matched to an optimal M&I type in storage formats such as flat files, look up tables, databases, combinations thereof, or the like. The feature classifier may be stored local to the M&I system controller 20 in the data storage device 24 or in high volume data storage systems such as on-premises factory enterprise systems or cloud server systems or through a combination of both local and remote data storage systems. The feature classifier includes descriptor tags such as external surface, internal surface, in domain geometry, thin section, thick section, safety critical, high cost and the like, and multiple feature classifications can be tagged to any particular feature. The M&I system controller 20 matches the optimal M&I sensor type to the feature classifications through the identification and recognition of patterns in M&I sensor type selection for specific product features in previously generated M&I programs.

An example of a feature classification with matched sensor type includes a medical implant with descriptor tags comprising "external surface", "surface roughness" and "safety critical" which is matched to a touch probe sensor type based on previously generated M&I programs. A further example could include an injection moulded polycarbonate component with descriptor tags comprising "in domain" and "high severity" which is matched to an ultrasonic sensor type based on previously generated M&I programs.

The M&I system controller 20 generates an M&I inspection path to position and orientate the OUT in order to present the product features for M&I to the M&I subsystems 5 according to the feature classifier. Efficient positioning and orientation of the OUT is calculated using motion planning techniques based on the geometry of the OUT defined in the CAD files combined with the registered individual coordinate frameworks of the object clamping unit 4 and the M&I subsystems 5. The M&I system controller 20 combines the relative movements of the object clamping unit 4 and the Mail subsystems 5 using tool path optimisation techniques based on well-known algorithms such as the Traveling Salesperson Problem (TSP) to optimise the positioning and orientation of OUT and the M&I subsystems 5 for efficient M&I.

The M&I system controller 20 tunes Mad algorithms for each feature of interest by calculating acceptance criteria thresholds using the output of M&I sensors for traceable artefacts which are selected as known to meet the acceptance criteria and known to be rejectable. The M&I systems tunes the setup parameters of the individual M&I sensors to provide a distinction in sensor output after M&I between known acceptable and known rejectable features of the traceable artefacts, thereby setting up an accept reject classifier. The M&I can increase the resolution of the accept reject classifier by several means including but not limited to the combination of repeat measurements with the same sensor, repeat measurements with the same sensor with sensor setting adjustments (e.g. integration time for an optical sensor), repeat measurements with the same sensor from adjusted positions, and/or repeat measurements using an alternative type of sensor.

Fig. 9A illustrates, as an example, the output of a single M&I sensor which cannot repeatedly distinguish between an acceptable and rejectable feature. The M&I system controller 20 cannot calculate a distinct acceptance threshold as some repeat outputs for the rejectable feature overlap with some of the repeat outputs for the acceptable feature. Upon identification of the lack of a distinct acceptance threshold, the M&I system tunes the M&I algorithm by taking repeat measures with and/or without sensor setting adjustments and recalculates the acceptance threshold. Taking an optical sensor as an example, the M&I system repeats the image acquisition without setting adjustments and/or with setting adjustments such as integration times, alternate sensor positions and the like. The sensor outputs are combined using simple arithmetic operations (e.g. addition, subtraction, multiplication, division and combinations thereof) or more complex but well-known machine learning algorithms such as artificial neural networks and the like, to determine if a distinct acceptance threshold for the feature can be established. When the M&I system controller establishes a distinct acceptance threshold for the feature, the M&I system controller stores the M&I algorithm comprising the sensor settings and the acceptance threshold for this feature, and the M&I system controller 20 repeats the self-tuning procedure to develop the M&I algorithm for the next feature.

In cases where a distinct acceptance threshold for a feature cannot be established with a single M&I sensor, the M&I system controller 20 increases the resolution by repeating the single sensor self-tuning procedure using additional sensors and combines the multiple outputs from multiple sensors until a distinct acceptance threshold is established. Figure 9B shows the combination of multiple sensor outputs with and without sensor setting adjustments for multiple sensors using simple arithmetic operations (e.g. addition, subtraction, multiplication, division and combinations thereof) or more complex but well known machine learning algorithms such as artificial neural networks and the like, to produce higher resolution M&I output. The increased resolution reduces output variation and provides for greater discrimination capability of the M&I system between acceptable artefacts and rejectable artefacts as illustrated in Fig. 9C.

The final stage in generating the M&I program optimises the M&I cycle time. Having established the self-tuned tuned M84.1 algorithms for each of the features with higher resolution M&I output if required, the M&I system controller 20 stores a serialised sequence of M&I procedures for each sensor for each feature. Fig. 10A illustrates the total serialised M&I cycle time for a total quantity of "L" features with the M&I self-tuned procedure implementing a total quantity "N" sensors. The M&I system controller 20 matches sensors which are not deployed for M&I with features which are not undergoing M&I. Fig. 10B illustrates an optimised M&I sequence which has reconfigured the serialised sequence such that the sensors S2 and SN which follow Si to carry out M&I for Feature 1 in the serialised sequence (Fig. 10A) are deployed to carry out M&I on other features in parallel with the M&I of Feature 1 by sensor Si. In Fig. 10B, sensor S2 carries out M&I for Feature 2 and sensor SN carries out M&I for Feature [while sensor Si carries out M&I for Feature 1. In reducing and/or eliminating sensor waiting times, the M&I system controller 20 reduces the overall cycle time as shown in Figure 10B. In addition, the M&I system controller 20 uses tool path optimisation techniques based on well-known algorithms such as the Traveling Salesperson Problem (TSP) to reduce the time required for each sensor to move from one feature to the next feature which includes logic to avoid collisions between the OUT 10, the multi-axis clamping unit 4 and the M&I subsystems 5 and disturbance of sensors in an active M&I procedure due to system movements.

The M&I system of the present invention enables manufacturers to monitor process drift and adjust process parameters using predictive manufacturing models established by the manufacturer through process studies such as designed experiments, equipment verification and validation, and process validation, where the effects of process input variation on process output variation has been qualitatively and quantitatively established and is fully understood.

Process drift occurs over time and can be monitored and controlled to ensure the drift stays within production parameters. Process drift directly effects the OUT critical dimensions and quality parameters, and therefore process drift is directly linked to component tolerance control. The M&I system makes process adjustments through closed loop feedback upon detection of drift which eliminates drift and ensures the quality parameters for the final produced components are centred within the control limits for each of the quality parameters. Correction of process drift is particularly complex when quality parameters for the OUT vary post production and require time to stabilise after the OUT has been produced. This complexity is particularly relevant in processes involving materials undergoing a state change (e.g. solidification, crystallization), viscoelastic deformation, thermomechanical deformation and the like.

Examples of such processes include but are not limited to injection moulding, polymer extrusion, pressure die casting, and the like.

Fig. 11A shows a quality parameter for an OUT measured with the M&I system of the present invention immediately post production, at time periods such as one hour, two hours and three hours post production, and also at the end of a stability period where further changes in quality parameters are negligible. Fig. 11A illustrates the quality parameter remains within the upper specification limit (USL) and the lower specification limit (LSL) post production and throughout the stability period. In the case of Fig. 11A, the quality parameter depicted is L representing the Length of an OUT feature which reduces due to post production shrinkage. Immediately after production the OUT feature length is L+60, while one hour, two hours, three hours after production the length is L+61, [+62, L+63 respectively, and after the stability period, the length stabilises to L, where L+80 > L+81 > L+82 > L+83 > L. It should be noted that post production transient quality parameters are not limited to dimensions and can include parameters such colour, finish (texture), defect count, density, porosity and the like.

The M&I system characterises changes in quality parameters over the stability time period ranging from immediately post production to the end of the stability period and this enables the M&I system to develop a precise model for the post production transient characteristics of the quality parameter. The M&I system models the transient characteristics of the quality parameter using well known modelling techniques such as but not limited to linear regression, non-linear regression, curve fitting and/or the like Fig. 11B shows the effects of process drift on the quality parameter whereby the quality parameter remains with specification (within the USL and LSL) immediately post production and for several hours after production. However, before the end of the stability period the quality parameter goes out of specification resulting in a defective component after the OUT has fully stabilised.

Having established a model for the post production transient characteristics of the quality parameter, the M&I system calculates a time dependent upper control limit (UCL) and a time dependent lower control limit (LCL) based on transient characteristics of the quality parameter, as shown in Fig. 11C. The M&I system communicates with the production equipment to determine the time elapsed since the production of the component undergoing the M&I procedure. Using the production elapsed time to calculate the time dependent UCL and La, the M&I system detects process drift by determining if the quality parameter is outside the time dependent UCL and LCL. In such cases, the M&I system adjusts the process parameters using the predictive manufacturing models established by the manufacturer to correct any detected process drift. The M&I system determines whether the quality parameters for components produced after the process parameter adjustments are better centred within the time dependent UCL and LCL and makes further process parameter adjustments should further centring be required, hence the process drift is corrected by means of a closed loop feedback system ensuring the process produces high quality components.

The M&I system controller maintains the history of process parameter adjustments by storing the process parameter adjustments to the data storage device 24. The M&I system controller monitors the frequency of process parameters adjustments and creates an alert if the frequency of process parameter adjustment are higher than a process parameter adjustment frequency threshold thereby enabling the manufacturer to review production equipment in advance of a process failure and/or trigger preventative maintenance procedures.

Fig. 12 is a flow chart illustrating the M&I steps taken using the M&I system of the invention. The fixtures 7 on the multi-axis clamping unit 4 grip the OUT without deforming or damaging the OUT by accommodating the tolerance band variation and distributing the grip contact area to minimise local stresses, thereby presenting the OUT in its natural state. The multi-axis clamping unit 4 is configured to position and orient the OUT to present the region of interest of the OUT for M&I of a quality attribute associated with the region of interest.

If required and in parallel to the multi-axis clamping unit 4 positioning and orientation, the M&I subsystem 5 optimally selected from the M&I program generation process is also positioned to carry out the M&I for the quality attribute associated with the region of interest. If the quality attribute requires high precision M&I, the M&I system carries out a further M&I with or without an adjustment to the sensor settings (e.g. sensor positioning, sensor exposure time, etc.) and/or M&I with an alternative sensor for a combination of multi sensor outputs in accordance with the multiple sensor tuning procedure determined as part of the Mad program generation.

Positioning and orientation of the OUT by the multi-axis clamping unit 4 along with the positioning of the M&I subsystem 5 is repeated to carry out M&I for the other quality attributes on other regions of interest until M&I is completed for the entire OUT according to the M&I program.

The Metrology and Inspection system of the present invention provides a heterogeneous metrology system which automatically measures and identifies issues such as quality defects, moulding defects sink, warp, discolouration, etc. The M&I system of the present invention adjusts the manufacturing process by signalling a required process change after evaluation of quality, for example after identifying defects or detecting a shift in quality parameter to outside an established control limit.

The system of the present invention provides a much improved automated and intelligent Metrology and Inspection system employing a multiple of M&I types. Deploying algorithms the system is able to select the appropriate Metrology and Inspection types to measure and inspect an object to be tested in a fast and efficient manner and communicate and/or adjust for any corrections required in the production procedure.

Throughout the specification the term object under test (OUT) is taken to comprise any object or component part thereof.

The invention is not limited to the embodiments hereinbefore described, with reference to the accompanying drawings, which may be varied in construction and detail.

Claims (25)

1. Claims 1. An automated and intelligent Metrology and Inspection system comprising; a rigid base platform; at least one detachably mounted multi-axis object clamping unit; at least one detachably mounted multi-axis arm positioning unit comprising a measurement and inspection subsystem; and a system controller.
2. 2. An automated Metrology and Inspection system as claimed in claim 1 comprising an in-built verification module for self-calibrating the metrology system using traceable artefacts.
3. 3. An automated Metrology and Inspection system as claimed in claim 1 or 2 wherein the system controller automatically selects a measurement and inspection subsystem to optimise the Metrology and Inspection of an object.
4. 4. An automated Metrology and Inspection system as claimed in any of claims 1 to 3 wherein the system controller provides system learning and adjustment to optimise and automatically tune the measurement process for the object being measured.
5. 5. An automated Metrology and Inspection system as claimed in any preceding claim wherein the system controller coordinates the movement and positioning of the object to be measured and inspected using the multi-axis object clamping unit with the measurement and inspection subsystem.
6. 6. An automated Metrology and Inspection system as claimed in any preceding claim wherein the clamping unit comprises fixtures to clamp the object in its natural state.
7. 7. An automated Metrology and Inspection system as claimed in claim 6 wherein the clamping system fixtures are manufactured from a polymer material.
8. 8. An automated Metrology and Inspection system as claimed in any preceding claim wherein the measurement and inspection subsystem comprises surface based and/or sub-surface measurement and inspection sensors.
9. 9. An automated Metrology and Inspection system as claimed in claim 8 wherein the sensors are selected from any one or more of a touch probe, image sensor, ultrasound sensor, hybrid probe or computerised tomography module.
10. 10. An automated Metrology and Inspection system as claimed in any preceding claim wherein the rigid base platform is manufactured from a high density rigid anti-vibration material.
11. 11. An automated Metrology and Inspection system as claimed in any preceding claim wherein the device is detachably mounted to a conveyance system.
12. 12. An automated Metrology and Inspection system as claimed in any preceding claim comprising a single platform Metrology and Inspection system.
13. 13. A method of carrying out non-destructive measurement and inspection of an object comprising a Metrology and Inspection system as claimed in any preceding claim.
14. 14. A method of measuring and inspecting an object comprising the steps; clamping the object to be measured and inspected; positioning the object to present a region of interest to a plurality of measurement and inspection sensors; positioning at least one of the measurement and inspection sensors to measure and inspect an attribute in a region of interest of the object; positioning another measurement sensor to measure and inspect an attribute in a region of interest of the object; gathering and collating the measurement data from the sensors; and communicating the data to a system controller. 15. 16. 17. 18.
15. The method as claimed in claim 14 wherein the measurement and inspection sensors are selected from any one or more of a touch probe, hybrid probe, image sensor, ultrasound sensor and or computerised tomography module.
16. The method as claimed in claim 14 or 15 wherein the system controller enables system learning and adjustment to optimise and automatically tune the measurement process for the object being measured.
17. The method as claimed in any of claims 14 to 16 wherein the system controller comprises an in-built verification module for self-calibrating the metrology system using traceable artefacts.
18. The method as claimed in any of claims 14 to 17 wherein the system controller generates a database of product measurement configurations to generate an optimised measurement program for the object to be measured.
19. 19. The method as claimed in claim 18 wherein the generated database allows the system to identify and predict time dependent quality attributes of the object at discrete time points throughout the process and according to end use parameters of the object.
20. 20. The method as claimed in any of claims 14 to 19 wherein the system automatically adjusts the measurement process in response to any deviation in the required time dependent quality attributes of the object.
21. 21. The method as claimed in any of claims 18 to 20 wherein the generated database allows the Metrology and Inspection system to identify and order the quality attributes of an object according to the end use parameters of the object.
22. 22. The method as claimed in any of claims 14 to 21 wherein the gathering and collating of the measurement data allows the system to capture-in-line critical quality defects.
23. 23. The method as claimed in any of claims 14 to 22 wherein the gathering and collating of the measurement data allows the system to monitor and control process drift and provide feedback to manufacturing systems in-line to make the required adjustments to control any deviation in process drift.
24. 24. The method as claimed in any of claims 14 to 23 wherein the gathering and collating of the measurement data allows the system to predict process failure and pre-empt maintenance issues.
25. 25. The method as claimed in any of claims 14 to 24 wherein the system controller reduces overall production cycle time through multiple and parallel measurements and inspections on different features of the object.