Manufacturing method and equipment

Abstract

A method for manufacturing an article is disclosed, the method comprising using a coordinate measuring machine to: obtain three-dimensional point coordinate measurements of a first part (70) of the article that is already in place, and, based on the measurements of the first part (70), position a second part (80) of the article in a predetermined spatial relationship relative to the first part (70). The predetermined spatial relationship is defined in more than three degrees of freedom. Positioning the second part (80) relative to the first part (70) includes controlling the machine to move the second part (80) relative to the first part (70) in more than three degrees of freedom. The machine is controlled to maintain the first and second parts (70, 80) in the predetermined spatial relationship while performing operations to fix the first and second parts in the predetermined spatial relationship. When the first and second parts (70, 80) are in the predetermined spatial relationship, the second part (80) does not directly contact any other part of the article, at least not in a manner that would interfere with or affect the predetermined spatial relationship.

Description

Technical Field

[0001] The present invention relates to a manufacturing method and a manufacturing device. Background Art

[0002] Equipment for automated assembly of components is known. For example, US 6266869 describes an apparatus and associated methods for assembling the various components of a computer hard disk drive. In particular, US 6266869 describes an assembly apparatus or robot comprising an arm that can move along three orthogonal axes (X, Y and Z). The movable arm carries a vacuum chuck for picking up components, an adhesive dispensing nozzle, and a UV light source for curing the deposited adhesive. A tray placed on a flat layer of the apparatus carries a plurality of components to be assembled. In use, adhesive is first dispensed onto a selected area of ​​a first component using a glue nozzle. A second component is then picked up by the vacuum chuck and placed on the first component. The components are imaged by a local imaging system to establish the positions of the components relative to each other. UV radiation from a UV light source is then used to cure the adhesive. In this way, the various subassemblies of a hard disk drive can be automatically assembled. Although automated assembly equipment of the type described in US 6266869 allows automated assembly of certain components, the ability of such equipment to assemble complex structures with high precision is limited.

[0003] It has also been proposed previously to use a Stewart platform or a hexapod machine to accomplish the placement of components. For example, DE10055185 describes a technique for placing components on a substrate mounted on a rotatable table using a hexapod machine. However, as with US 6266869, the ability to use such equipment for high-precision automated manufacturing of complex products is limited. Summary of the invention

[0004] According to a first aspect of the present invention, there is provided a method for manufacturing an article, the method comprising using a coordinate measuring machine to obtain (coordinate) measurement results of a first (already assembled) part of the article, and positioning a second part of the article relative to the first part in a predetermined spatial relationship based on the (coordinate) measurement results of the first part.

[0005] Coordinate measuring machines are particularly suitable for measuring point coordinates of objects and, unlike positioning machines, are provided for positioning components within the working volume of the machine (e.g. supported on a movable platform of the machine). Such positioning machines are particularly suitable for the task of positioning or placing objects, but are not particularly suitable for performing measurement functions, at least not for measuring point coordinates on the surface of objects. A common example of a positioning machine is a pick and place machine, such as used in the PCB manufacturing industry, which blindly picks parts from a tray and places these parts on a PCB substrate. Some kind of alignment process, such as using reference features or benchmarks, is required to ensure that the machine is picking from the correct position and that the PCB is where the machine expects it to be, but the pick and place machine does not perform any measurements on parts that are already on the PCB, and in particular does not rely on this measurement result when placing subsequent components.

[0006] Embodiments of the present invention may be considered as a metrology-assisted manufacturing method in which a coordinate measuring machine (or metrology machine) is used for the primary purpose of measuring a part with high accuracy, but is also given the additional functionality of placing or positioning other parts relative to the measured part based on the measurements taken. Using such a technique, the accuracy of the manufacturing method is limited only by the accuracy of the coordinate measuring machine itself, and does not rely on, for example, complex and / or expensive fixture systems. Furthermore, in preferred embodiments in which the part to be placed or assembled onto the article is held off the surface of the article and fixed in place (e.g., by applying a curable adhesive in a gap and allowing it to cure), the substrate on which the part is to be placed does not need to be particularly accurately formed or held, because the relative positioning of the part to be assembled onto the substrate is entirely determined by the metrological accuracy of the coordinate measuring machine and is completely independent of the substrate or fixture; the part effectively "floats" above the substrate in the correct relative position based on the accuracy of the coordinate measuring machine. This novel use of the coordinate measuring machine provides significant manufacturing advantages.

[0007] The first part of the article may be or may include a feature of the article (e.g., an integral feature) wherein the second part is positioned relative to the feature. In other words, the first part is not necessarily a part that is separable from the article (or has been previously assembled or placed on the article); instead, the first part may simply be an integral part of the article, such as a hole, recess, protrusion, or other such geometric shape or feature formed on or in the surface of the article.

[0008] The method may comprise obtaining (coordinate) measurements of the second part using the coordinate measuring machine, wherein the second part is positioned in the predetermined spatial relationship relative to the first part based on the (coordinate) measurements of the first part and the second part.

[0009] The measurement results of the first part can be used to establish a reference system for the first part; the measurement results of the second part can be used to establish a reference system for the second part; the relationship between the first reference system and the second reference system can be established; and the established relationship can be used to move the first part and the second part to a predetermined spatial relationship in the common reference system.

[0010] Establishing a relationship between the first reference system and the second reference system may include determining position information associated with at least one point or feature that is common or coincident in the two reference systems.

[0011] The common reference system may be the reference system of the first part.

[0012] The first reference system and the second reference system may be a first coordinate system and a second coordinate system, respectively. The established relationship may be a coordinate transformation between the first coordinate system and the second coordinate system.

[0013] The predetermined spatial relationship may be defined (or specified) in more than three degrees of freedom, and measurements (of the first part and / or the second part) may be obtained and may be of a type that enables this.

[0014] Positioning the second part relative to the first part may include causing (or controlling the machine to cause) the second part to move relative to the first part in more than three degrees of freedom, such as four degrees of freedom, five degrees of freedom or six degrees of freedom. Positioning the second part relative to the first part may include actuating axes of the machine corresponding in number to the degrees of freedom. For example, positioning the second part relative to the first part may include actuating four axes of the machine (to move the second part relative to the first part in four degrees of freedom), or actuating five axes of the machine (to move the second part relative to the first part in five degrees of freedom), or actuating six axes of the machine (to move the second part relative to the first part in six degrees of freedom). Accordingly, depending on the number of degrees of freedom involved, positioning the second part relative to the first part may be referred to as four-axis positioning, five-axis positioning or six-axis positioning. For example, by supporting one or both of the first part and the second part on a rotating table, or via an articulated joint (such as Renishaw) probe head), positioning can even be in more than six degrees of freedom.

[0015] The measurement results (of the first part and / or the second part) may be three-dimensional measurements, ie measurements in three dimensions.

[0016] The measurements (of the first part and / or the second part) may be in three or more degrees of freedom.

[0017] These measurements may be obtained by moving (or controlling the machine to cause movement) in three or more degrees of freedom, preferably in four degrees of freedom, more preferably in five degrees of freedom, and more preferably in six degrees of freedom.

[0018] These measurements can be obtained by moving (or controlling the machine to move) a measuring device in three or more degrees of freedom, preferably in four degrees of freedom, more preferably in five degrees of freedom, and more preferably in six degrees of freedom. The measuring device can be of the type listed below (e.g., a probe, a contact probe, a touch probe, a touch trigger probe, an analog probe, a scanning probe, or a camera-based measuring device).

[0019] Obtaining the measurements (of the first part and / or the second part) may comprise actuating three or more axes (or degrees of freedom) of the machine, such as four axes or five axes or six axes. For example, when the machine is a hexapod coordinate measuring machine comprising six extendable legs (corresponding to six axes), the measurements may be obtained by actuating all six extendable legs (all six axes).

[0020] The measurement results (of the first part and / or the second part) may be coordinate measurement results.

[0021] The measurement results (of the first part and / or the second part) may be point coordinate measurement results.

[0022] The measurement results (of the first part and / or the second part) may be (or may include) machine coordinates (or coordinates derived therefrom). The machine coordinates may be defined in a machine coordinate system (eg, relative to a part coordinate system or a global coordinate system).

[0023] Positioning the second part relative to the first part may include controlling the machine to adopt a series of different machine coordinates (within a machine coordinate system).

[0024] The measurement results (of the first part and / or the second part) and the positioning of the second part may be based on (or performed within) the same machine coordinate system.

[0025] The coordinate measuring machine may include multiple (or a group of) measuring transducers (e.g., linear and / or rotary encoders; or length measuring transducers and / or angle measuring transducers), wherein the same multiple (or group of) measuring transducers are used to obtain (or derive) measurement results (of the first part and / or the second part) and to position the second part based on these measurement results.

[0026] The measurements may be based on or derived from the entire metrology loop of the coordinate measuring machine. This is in contrast to systems that measure, for example, by means of a camera-based or laser-based vision system attached to an end effector of a positioning machine such as a robot, where the robot is used merely to place the vision system within range of a target and to direct the end effector (and any components held by the end effector) toward the target based on real-time feedback from the vision system, without regard to measurements from rotary encoders of the rotary joints that make up the articulated robot arm. According to embodiments of the present invention, it is possible to determine a complete set of machine coordinates that, when set by the machine, causes a second part to be placed in a predetermined spatial relationship relative to a first part.

[0027] Positioning the second part in a predetermined spatial relationship relative to the first part may comprise: calculating a set of machine coordinates based on the measurements (of the first part and / or the second part) that will position the first part and the second part in the predetermined spatial relationship; and controlling the machine to adopt the calculated machine coordinates. The machine may be controlled to adopt the calculated machine coordinates directly or substantially directly, i.e. substantially in a single movement. This is to be contrasted with a series of iterative or incrementally smaller movements that may be performed, for example, based on visual feedback from a separate camera or imaging system.

[0028] The method may include controlling the machine to maintain the first part and the second part in the predetermined spatial relationship while performing an operation to fix the first part and the second part in the predetermined spatial relationship. This may enable the second part to be released from the second platform while the first part and the second part are still in the predetermined spatial relationship without requiring support from the second platform.

[0029] Controlling the machine to hold the first part and the second part in the predetermined spatial relationship may include controlling the machine to maintain calculated machine coordinates.

[0030] The fixing operation may include applying a fixing medium that contacts the second part when the second part is in the predetermined spatial relationship with the first part; and activating the fixing medium to fix the first part and the second part in the predetermined spatial relationship.

[0031] The method may include applying the securing medium prior to moving the first part and the second part into the predetermined spatial relationship, and then activating the securing medium while the first part and the second part are in the predetermined spatial relationship.

[0032] The securing medium may be a curable adhesive, wherein activating the securing medium may include curing the adhesive.

[0033] The fixing operation may include a welding process, wherein the fixing medium and the activation of the fixing medium are the result of performing the welding process. For example, the fixing material may be a welding (e.g., molten) material produced by the welding process, wherein the activation of the fixing material is the hardening or cooling of the welding material.

[0034] The welding process may be a laser welding process, but may also be a bonding process, a friction welding process, an electron beam welding process, a hot air bonding process or an electrochemical process.

[0035] Advantageously, when the first part and the second part are in a predetermined spatial relationship, the second part does not directly contact (e.g., does not touch) any other part of the article, at least not in a manner that would hinder or interfere with or affect the predetermined spatial relationship.

[0036] The method may include leaving a gap between the second part and any other parts of the article when in the predetermined spatial relationship.

[0037] The gap can be at least partially bridged by a fixing medium applied during the fixing operation.

[0038] The gap is preferably at least 25 μm, more preferably at least 50 μm, more preferably at least 100 μm, for example determined as an average value of the overlapping area between the relevant parts.

[0039] The method may include using the established relationship to determine a location to apply the securing medium.

[0040] The machine may include a first platform and a second platform movable relative to each other, and the method may include supporting the first part on the second platform and supporting the second part on the first platform. Positioning the second part relative to the first part may include controlling the machine to move the first platform and the second platform relative to each other.

[0041] Supporting the second part on the first platform may include picking up the second part using a picking device supported on the first platform.

[0042] The picking device may include a gripper.

[0043] The second part may be kinematically (or at least pseudo-kinematically) coupled to the pickup device when supported by the first platform. The pickup device may be provided with a set of kinematic (or at least pseudo-kinematic) features that engage with the second part when the second part is supported by the first platform. The second part may be provided with a corresponding set of kinematic (or at least pseudo-kinematic) features that engage with the kinematic (or at least pseudo-kinematic) features of the pickup device. In the case where the relative constraint between the pickup device and the second part is required to be in less than six degrees of freedom, the surface of the second part that engages with the kinematic (or at least pseudo-kinematic) features of the pickup device may be designed accordingly to achieve the desired degree of constraint. For example, in the case where the second part is a ball, and the constraint relative to the pickup device only needs to be in three translational degrees of freedom (rotation in three degrees of freedom around the center of the ball is allowed), sufficient kinematic coupling is achieved by having kinematic features on the pickup device (e.g., three point contacts are arranged on the spherical surface corresponding to the ball).

[0044] The method may comprise obtaining measurements of the second part using a model of the second part and knowledge of the position of the second part relative to the first platform by means of a kinematic connection, rather than obtaining measurements of the second part using the coordinate measuring machine.

[0045] The first platform may be a movable platform and the second platform may be a fixed platform.

[0046] The method may include measuring the first part using a first probe supported on the first platform.

[0047] Measuring the first part using the first probe may include moving the first platform and the second platform relative to each other to place the first probe in sensing relationship with the first part.

[0048] The first probe may be a movable probe.

[0049] The first probe may be a contact probe. The first probe may be a touch probe. The first probe may be a touch trigger probe. The first probe may be an analog probe. The first probe may be a scan probe.

[0050] The method may include measuring the second part using a second probe supported on the second platform.

[0051] Measuring the second part with the second probe may include moving the first platform and the second platform relative to each other to place the second probe in sensing relationship with the second part.

[0052] The second probe may be an immobilized probe.

[0053] The second probe may be a contact probe. The second probe may be a touch probe. The second probe may be a touch trigger probe. The second probe may be an analog probe. The second probe may be a scan probe.

[0054] The method may include measuring the first probe using the second probe and / or vice versa to establish a relationship between the first reference system and the second reference system.

[0055] Measuring the first probe with the second probe and / or vice versa may include moving the first platform and the second platform relative to each other so that the first probe and the second probe are in sensing relationship with each other.

[0056] The first probe and the second probe may each include a stylus tip (a stylus having a stylus tip). The common or coincident point may be the center point of the stylus tips of the first probe and the second probe when the first platform and the second platform are in positions relative to each other that will cause (the respective centers of) the stylus tips of the first probe and the second probe to be located at the same position.

[0057] When one of the first probe and the second probe is a touch trigger probe and the other of the first probe and the second probe is a scanning probe or an analog probe, the method may include measuring or characterizing the surface of the stylus tip of the touch trigger probe using an extrapolation-to-zero technique and determining the center point of the stylus tip therefrom.

[0058] The second part may be supported on a rotatable table. The rotatable table may be supported on the first platform. Positioning the first part relative to the second part may include controlling the machine to rotate the rotatable table relative to the first platform.

[0059] The article (and the first part therewith) may be supported on a rotatable table. The rotatable table may be supported on a second platform. Positioning the first part relative to the second part includes controlling the machine to rotate the table relative to the second platform.

[0060] The first platform and the second platform are movable relative to each other in more than three degrees of freedom to position the second part relative to the first part.

[0061] The first part may be a support or substrate part of the article.

[0062] The first part and the second part may be operative parts of the article having a function in use of the article, rather than merely reference features, datums, etc. having a function only during manufacture of the article.

[0063] These parts may be functionally and / or mechanically and / or optically interconnected parts of the final article.

[0064] The second part may be supported on the first part in the resulting article. If several parts are supported in this manner, a stacked or tandem arrangement may result. The fixing medium used in the fixing operation may be disposed between the first part and the second part. The fixing medium used in the fixing operation may be disposed in contact with the first part and the second part.

[0065] In the resulting article, the first part and the second part may be supported on a base part of the article. It is possible that the first part and the second part are not supported directly on each other. If several parts are supported in this way, a side-by-side or parallel arrangement is produced. The fixing medium used in the fixing operation may be arranged between the second part and the base part. The fixing medium used in the fixing operation may be arranged in contact with the second part and the base part.

[0066] Combinations of parallel and series arrangements of components are also possible.

[0067] The first part may be or may include a base part or substrate of the article.

[0068] The method may include using a measuring device other than a probe to obtain the measurement results. A measuring device such as a camera may be used. Such a camera-based measuring device may include at least two, preferably three, imaging sensors arranged at different respective angles or orientations relative to the target (i.e., the part being measured). A non-contact measuring device may be used. An optical measuring device may be used.

[0069] Obtaining measurements of a part may include obtaining measurements of one or more features of the part.

[0070] Obtaining measurements of a part may include obtaining measurements of one or more discrete points on a surface of the part.

[0071] The coordinate measuring machine may be a machine adapted to measure the geometry or geometric features of a physical object in three dimensions by sensing discrete points on the surface of the object using a probe.

[0072] The coordinate measuring machine may be a machine having a coordinate measuring device, such as a probe, for measuring the coordinates of points on the surface of an object.

[0073] The coordinate measuring machine may be a non-Cartesian coordinate measuring machine.

[0074] The coordinate measuring machine may be a parallel kinematic coordinate measuring machine. Such a measuring machine may have a plurality of metrological axes and / or drive axes arranged in parallel rather than in series, so that positioning errors associated with the respective axes are not cumulative as they are in a serial kinematic coordinate measuring machine; this generally results in increased measurement accuracy and better metrological results.

[0075] The coordinate measuring machine may include a plurality of extendable legs.

[0076] The coordinate measuring machine may be a hexapod coordinate measuring machine comprising six extendable legs. Alternatively, the machine may be a pentapod machine comprising five extendable legs. Alternatively, the machine may be a quadruped machine comprising four extendable legs.

[0077] The coordinate measuring machine may be in the form of an articulated arm having a plurality of rotary joints arranged in series. This may be considered similar to what is commonly referred to as a robotic arm.

[0078] The measurement accuracy (or error) of the coordinate measuring machine may be less than 50 μm, more preferably less than 25 μm, more preferably less than 10 μm, more preferably less than 5 μm, and more preferably less than 1 μm.

[0079] The machine coordinates of the coordinate measuring machine may include values ​​respectively associated with and / or derived from the lengths of the plurality of extendable legs.

[0080] The plurality of measurement transducers may be respectively associated with the plurality of extendable legs.

[0081] The second part and the measuring device (eg, a probe) used to obtain measurements of the first part may be supported simultaneously on a common platform of the machine, the platform being moved when measuring the first part and when positioning the second part.

[0082] The method may include repeating the method for one or more additional second parts of the article. In each repeated execution of the method, the first part may be any one or more parts of the article produced by any previous execution of the method.

[0083] The first part in at least one iteration of the method may include at least one second part from any previous iteration of the method.

[0084] In a subsequent execution of the method, the second part from the previous execution of the method (now considered to be the first part because it has been placed on the article and the new second part is being placed) may be one of the parts measured by the coordinate measuring machine and used to locate the new second part. It is also possible that in a subsequent execution of the method the second part from the previous execution of the method (now the first part because it has been placed on the article) is not measured, but that (new or pre-existing) measurements of other parts of the article are relied upon in locating the new second part.

[0085] Using the machine to obtain measurements of the first part in at least one iteration of the method may be equivalent to using measurements of the first part obtained in a previous iteration of the method. In other words, if the first part has already been measured in a previous iteration of the method, it need not be measured again, only the measurements already obtained for the first part need be retrieved (using the coordinate measuring machine, e.g. its machine controller).

[0086] The or each second part may be or may form part of a bearing assembly for an extendable leg of a coordinate positioning machine, or may be a ball or tip of a stylus for a measurement probe. The first part may be or may form part of a readhead or readhead holder for an extendable leg of a coordinate positioning machine, or may be a stem of a stylus for a measurement probe.

[0087] Accordingly, the present invention is applicable to a method of manufacturing an extendable leg for a coordinate positioning machine and / or a stylus for a measuring probe.

[0088] According to a second aspect of the present invention, a method for manufacturing an article having a plurality of parts is provided, the method comprising: for a first selected part among the plurality of parts, at least performing a measuring step and a positioning step of the method according to the first aspect of the present invention to position the first selected part on the article; and for each subsequently selected part among the plurality of parts, at least performing the positioning step of the method according to the first aspect of the present invention, and optionally also performing a measuring step to position the subsequently selected part on the article, wherein the positioning step uses measurement results obtained when the method is performed on the currently selected part and / or any previously selected part.

[0089] At least one of the plurality of parts may be a module that is made from a plurality of other parts of the plurality of parts during the course of performing the method.

[0090] According to a third aspect of the present invention, there is provided a manufacturing system or apparatus, the manufacturing system or apparatus comprising a coordinate measuring machine, the coordinate measuring machine being configured to perform the method according to the first aspect or the second aspect of the present invention.

[0091] According to a fourth aspect of the present invention, there is provided a computer program which, when run by a controller for a coordinate measuring machine, causes the controller to operate the coordinate measuring machine to perform the method according to the first aspect or the second aspect of the present invention.

[0092] According to a fifth aspect of the present invention, there is provided a computer readable medium having computer program instructions stored therein, wherein the computer program instructions are used to control a coordinate measuring machine to execute the method according to the first aspect or the second aspect of the present invention.

[0093] The "position" of a part should be understood as the position and / or orientation of the part in an appropriate number of degrees of freedom. In particular, the terms "position" and "positioning" should not be understood as being limited to describing only translational movement (e.g., movement in the X-axis, Y-axis, Z-axis), but are intended to describe translational movement and rotational movement or a combination thereof in a relevant number of degrees of freedom. For example, where position is defined in six degrees of freedom, both position and orientation are related. However, if position is defined in only three degrees of freedom, this may or may not include orientation. The terms "position" and "positioning" used herein will be interpreted accordingly. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Reference will now be made, by way of example, to the accompanying drawings, in which:

[0095] Figure 1A is a schematic diagram of a hexapod coordinate measuring machine having six extendable legs;

[0096] Figure 1B It is a schematic diagram arranged from bottom to top, such as Figure 1A As shown;

[0097] Figure 1C It is a schematic diagram arranged from top to bottom. Figure 1B An alternative to bottom-up deployment;

[0098] Figures 2 to 12 is a schematic diagram showing various stages of a manufacturing method embodying the present invention;

[0099] Fig.13 is a schematic diagram showing a product obtained by the method;

[0100] Fig.14 is a flow chart outlining a manufacturing method according to an embodiment of the present invention;

[0101] Figures 15 to 22 is a schematic diagram showing the concept of a reference system in an embodiment of the present invention;

[0102] Fig.23shows a more realistic arrangement of the various parts of an article made by a method embodying the invention;

[0103] Fig.24 and Fig.25 Provides a more realistic and practical implementation of articles made by methods embodying the invention;

[0104] Fig.26 Determining the amount of deviation between the probe coincidence point and a specific point on a part of an article supported on a moving platform for use when changing the rotation center of the moving platform;

[0105] Fig. 27 It is shown that the manufacturing method has been repeated to place an additional second part of the article side by side on the base part;

[0106] Fig.28 Shown Fig. 27 An alternative in which the first part comprises only the basic parts of the previous embodiment;

[0107] Fig.29 and Fig.30 They were shown Fig. 27 and Fig.28 An alternative stacking arrangement to a side-by-side arrangement;

[0108] Fig.31 Demonstrates the use of the concept to assemble one or more modules, and then applies the same concept to assemble the one or more modules into a larger whole (or complex product);

[0109] Fig.32 The application of a method embodying the invention to the manufacture of a metrological stylus is demonstrated;

[0110] Fig.33 showing an alternative placement of a second part onto a base part, wherein at least one point of the second part touches the base part; and

[0111] Fig.34 Shown in greater detail is how the v-grooves of the bearing assembly kinematically engage with the balls of the holder. DETAILED DESCRIPTION

[0112] Figure 1A A non-Cartesian coordinate measuring machine 10 is schematically illustrated. The coordinate measuring machine 10 generally includes a movable platform 12 and a fixed platform 14 that are supported and move relative to each other by a plurality of telescopic or extendable legs 16 disposed therebetween. The movable platform 12 and the fixed platform 14 may also be referred to as tables (or structures or parts), and the extendable legs 16 may also be referred to as struts (or actuators). In the case where there are six such extendable legs 16 (e.g., Figure 1A ), which is often referred to as a hexapod.

[0113] The extendable legs 16 are typically mounted on the platforms 12, 14 via ball joints 18, wherein each leg 16 has a respective ball joint 18 at one or both ends thereof (e.g., Figure 1A 17 (shown), or sharing a ball joint 18 at one or both ends with an adjacent leg 16. Each extendable leg 16 is typically formed as a pair of tubes, wherein one tube is telescopically moved within the other tube by a drive mechanism (e.g., a linear motor) to provide extension and retraction of the extendable leg 16, as indicated by arrows within each extendable leg 16, and as described in more detail, for example, in WO 2017 / 174966. As described in WO 2007 / 144573, a degree of separation may also be provided between the drive and measurement parts of each support.

[0114] Different relative positions between the movable platform 12 and the fixed platform 14 can be achieved by extending the legs 16 by different amounts. The relative position at any time is monitored by a plurality of length measuring transducers 17, one for each extendable leg 16. Each length measuring transducer 17 may include an encoder scale paired with a readhead, wherein the encoder scale is suitably mounted on one of a pair of telescopic tubes and the readhead is suitably mounted on the other telescopic tube. Extension of the legs 16 thus causes the encoder scale to move past the readhead, thereby allowing the length of the extendable leg 16 to be measured. The computer controller 15 operates to set the length of each extendable leg 16 to provide the desired relative movement between the platforms 12, 14. By having six such length measuring transducers 17, relative position can be measured in six corresponding respective degrees of freedom (three translational degrees of freedom and three rotational degrees of freedom).

[0115] The workpiece 19 is mounted on the lower (fixed) platform 14, and the measuring probe 13 is mounted on the upper (movable) platform 12. A working volume (or operating volume) 11 is defined between the upper (movable) platform 12 and the lower (fixed) platform 14, wherein the measuring probe 13 is positioned (i.e. moved to a desired position) in the working volume 11 by operating the extendable legs 16. Figure 1A The arrangement can be referred to as a bottom-up arrangement because the extendable legs 16 extend upward from the fixed platform 14 to the movable platform 12. Figure 1B Alternatively, Figure 1CFor a top-down arrangement, as schematically shown in FIG, an extendable leg 16 extends downwardly from a fixed platform 14 to a movable platform 12, wherein a measurement probe 13 is mounted to a lower surface of the movable platform 12, and a workpiece is mounted to another portion of the fixed platform (or structure) 14 below the movable platform. These types of arrangements are discussed in more detail in WO 2019 / 073246, which also describes the use of a non-hexapod drive arrangement in combination with a hexapod metrology arrangement.

[0116] Now refer to Figures 2 to 12 The method can be described as a metrology-assisted manufacturing or assembly method, using reference Figure 1A A coordinate positioning machine 10 of the type described. Figures 2 to 12 The machine 10 is shown at different stages of the method, as will become clear below.

[0117] The machine 10 of the present embodiment includes a set of extendable legs 16, a first platform 12 and a second platform 14, wherein the first platform 12 is movable relative to the second platform 14 by operation of the extendable legs 16, as described above with reference to Figure 1A Accordingly, in this embodiment, the first platform 12 is a movable platform, and the second platform 14 is a fixed platform. The machine 10 of this embodiment is Figure 1A The machines shown differ primarily in what is attached to the movable platform 12 and what is placed on the fixed platform 14, and of course in how the machines operate.

[0118] The tool support 22 is attached to the first (movable) platform 12 via the sleeve 20, wherein the first (movable) measurement probe 30, the gripper 50 and the glue applicator 90 are attached to the tool support 22. On the second (fixed) platform 14, the second (fixed) measurement probe 40 is arranged, as well as the individual parts 60, 70 and 80 of the article manufactured (or assembled) in the method. Due to the limitation of schematically presenting the three-dimensional machine in only two dimensions, only Figure 8 (this is the stage at which the method is initially implemented) but all three tools 40, 50 and 90 are simultaneously supported on the tool support 22 (and therefore also on the movable platform 12 via the sleeve 20). The sleeve 20 has a suitable length to place the tool support 22 (and in particular the tools 40, 50 and 90) in a suitable position in the working volume 11 of the machine.

[0119] With the above arrangement, it can be seen in particular that there are two probes: a first (movable) probe 30 is arranged on the first (movable) platform 12, and a second (fixed) probe 40 is arranged on the second (fixed) platform 14. The reason for this arrangement will become clear below. The first probe 30 has a stylus tip (or probe tip) 32, and the second probe 40 has a stylus tip (or probe tip) 42.

[0120] Likewise Figure 2 As shown, the article being assembled has: a base part 60; a first part 70, which has been fixed to the base part 60; and a second part 80, which will be placed (as part of the method) on the base part 60 in a predetermined spatial relationship with the first part 70. The first part 70 has a representative feature 72, and the second part 80 has a representative feature 82, and it is particularly important that these representative features 72, 82 are accurately positioned relative to each other in the final article. The base part 60 (and the first part 70 together with it) is supported on the fixed platform 14 via a first support 21, and the second part 80 is supported on the fixed platform 14 via a second support 23; these fixed supports 21, 23 are used to raise the supported parts to a height that is more convenient for measurement and / or manipulation, but can also provide a clamping function to hold the supported parts in place.

[0121] Now briefly referring to other known manufacturing techniques, to put the embodiments of the present invention into context, when assembling components onto a printed circuit board, it is generally not critical to position the components on the circuit board absolutely or with respect to other components very precisely. Instead, a reasonable degree of manufacturing tolerance is allowed, since it is only necessary to position the contacts of the component over the correct corresponding pads on the circuit board so that the component will be in electrical contact with the pads via solder. In this regard, the manufacture of most printed circuit board assemblies (PCBAs) is carried out using surface mounting techniques including a reflow soldering stage. In this technique, the pads of the board are plated with solder paste before the components are placed. The components are then placed sequentially on the appropriate pads of the board using an automated "pick and place" machine, releasing each component so that it is only very loosely held by the uncured solder paste, i.e., the components are not fixed or firmly held in place before being released by the pick and place machine. The board is then placed into a reflow oven, which typically includes multiple stages for gradually heating (e.g., using heated gas or infrared radiation) the entire board until a temperature is reached at which the solder paste melts or reflows. The board is then slowly cooled, whereupon the molten solder solidifies and securely holds the component in place.

[0122] With the manufacture of PCBAs as described above, the placement of components on the circuit board does not need to be very precise due to the relatively large size of the pads. For the image-based system approach of US 6266869 (described further above), in which the components being assembled together are imaged by an imaging (e.g., video) system to establish their positions relative to each other, this approach is computationally intensive (and therefore relatively slow), and is relatively imprecise due to being an image-based approach. In addition, components may be slightly misaligned after being released from the machine and before being processed in the reflow soldering oven, but this is insignificant in the context of PCBA manufacture because precise spatial positioning is not required, only reliable electrical connections.

[0123] For embodiments of the present invention, it is assumed that a higher positional accuracy than is possible with these known methods is required and, in particular, that the first part 70 and the second part 80 must be precisely fixed in a predetermined spatial relationship relative to each other.

[0124] With this in mind, Figure 2 As can be seen in the figure, the first part 70 (particularly the representative feature 72) is at a slight angle relative to the base part 60 due to the small defect (e.g., a protrusion) 62 on the surface of the base part 60. It is important that the second part 80 (particularly the representative feature 82) is accurately aligned with the first part 70 (particularly the representative feature 72) regardless of any positional inaccuracies or defects associated with the already placed parts. For example, if a simple pick-and-place machine is used to place the second part 80 on the base part 60, such as the PCBA example mentioned above, the presence of the defect 62 on the base part 60 will not be taken into account, and thus the second part 80 (particularly the representative feature 82) will not end up accurately aligned with the first part 70 (particularly the representative feature 72). It is also possible that image-based methods cannot detect such small defects or misalignments and / or cannot detect them at a sufficiently high refresh rate. For PCBA manufacturing, it is sufficient to assume that the substrate is completely planar, but embodiments of the present invention are applicable to accurately positioning parts 70, 80 on defective and / or non-planar substrates or base parts 60.

[0125] Reference now Figure 3 , the first platform 12 and the second platform 14 are moved relative to each other so that the first probe 30 is in a sensing relationship with the first part 70. As described above, the relative movement of the first platform 12 and the second platform 14 is achieved by changing the length of the extendable leg 16 under the control of the controller 15 (see Figure 1A). This is equivalent to measuring the first part 70 at one or more points using the first probe 30 to provide a set of measurement results. For example, if it is known that the first part 70 is generally cubic, measurements can be made on each side of the first part 70 to establish the position of the side and how the plane of each side is oriented. If necessary, further measurements can be made (such as at one or more corners) to better characterize the first part 70, or fewer measurements can be made if only information about the plane of the top surface must be determined, for example. These measurements of the first part 70 are used to establish a reference system for the first part 70. These measurements of the first part 70 are three-dimensional point coordinate measurements. They can be collectively considered to be measurements in more than three degrees of freedom because they define both the position (three translational degrees of freedom) and orientation (at least one rotational degree of freedom, preferably three rotational degrees of freedom) of the first part 70.

[0126] like Figure 4 As shown, in this embodiment, the base part 60 is also measured using the first probe 30 in order to establish a reference frame for the base part 60. This may be necessary if one or more features on the base part 60 need to be located, which are used to determine the exact location where the second part 80 will be placed on the base part 60. For example, there may be one or more locating features (e.g., marks or recesses) on the base part 60, and the second part 80 will be placed over or in the locating features, so that the positioning of the second part 80 relative to the first part 70 is determined in part by the features on the first part 70 and in part by the features on the base part 60.

[0127] It is convenient to consider that the first part 70 includes the base part 60, so Figure 3 and Figure 4 A single step is shown of measuring the first part 70 (including the base part 60) using the first probe 30 to establish a reference frame for the first part 70 (including the base part 60). In other words, the first part 70 itself may have multiple parts, and any one or more of the multiple parts may be relevant to determining the reference frame for the first part and how the second part 80 is positioned relative to the first part 70.

[0128] In this embodiment, the first probe 30 (and the second probe 40) are contact or touch probes. Touch probes are well known. For example, to make a measurement using the first probe 30, the machine is controlled to bring the stylus tip 32 into contact with the object being measured. When a touch is sensed, the machine coordinates (e.g., the length of the extendable leg 16) are recorded, and from these machine coordinates the X, Y, Z coordinates of the touch point can be calculated. This assumes that the machine has been calibrated to provide the machine coordinates (e.g., Figure 1AThe common goal of machine calibration techniques is generally to specify a parametric model of the machine in question, in which a number of parameters are used to characterize the geometry of the machine. These parameters are initially assigned uncalibrated values ​​as a starting point for the machine geometry. During calibration, the machine is moved into a number of different postures (based on current estimates of the machine parameters). For each posture, the actual posture is measured using a calibrated measurement device, so that an indication of the error between the assumed machine posture and the actual machine posture can be determined. The task of calibrating the machine then amounts to determining a set of values ​​for the various machine parameters that minimize the error, using known numerical optimization or error minimization techniques (such as the Levenberg-Marquardt algorithm).

[0129] exist Figure 5 In the steps shown, the first probe 30 is then used to measure the second probe 40 (or vice versa), and these measurements are used to establish a relationship between the reference frame determined above for the first part 70 and the reference frame to be determined for the second part 80 (see below). This amounts to measuring the probe coincidence position, which is the machine position (i.e. the relative position of the first platform 12 and the second platform 14) that will place the stylus tip 32 of the first probe 30 in exactly the same position as the stylus tip 42 of the second probe 40. As this is not possible in practice, this is achieved by taking touch measurements around the second stylus tip 42 with the first stylus tip 32, and fitting a sphere to these measurements in order to determine where the coincidence point is (i.e. the position of the centre of the second stylus tip 42). The two probes 30, 40 may be arranged to have different stiffnesses to ensure that when the two stylus tips 32, 42 contact each other, the second probe 40 triggers in preference to the first probe 30, or vice versa.

[0130] As mentioned above, the coincidence probe calibration using two touch trigger probes may potentially be affected by the different stiffness of the probe rod and the kinematic spring in the X-axis and Y-axis directions relative to the Z-axis direction. In order to overcome this, it is also possible to use an analog or scanning probe instead of using two touch trigger probes to measure the touch trigger probe. The analog probe usually has a more uniform stiffness or response than the touch trigger probe on the X-axis, Y-axis and Z-axis. In addition, if the touch trigger probe is measured using an analog probe, the "extrapolation to zero" technique described in WO 2005 / 059471 or WO 2004 / 005849 can be used to provide a very accurate measurement result of the tip surface of another probe, and the probe coincidence position can be determined by performing spherical fitting as mentioned above from the tip surface. Before the touch trigger probe is out of position and triggered, extrapolation can be performed within the range of the deflection experienced by the analog probe. The analog probe can be moved relative to the touch trigger probe, or vice versa.

[0131] As described above, in this example, the first part 70 of the article has been set on the second (fixed) platform 14, while the second part 80 is still waiting to be used on the support 23. The next step is to support the second part 80 of the article on the first platform 12 so that it can be moved and placed in the appropriate position on the article. In this embodiment, this is achieved by picking up the second part 80 from the support 23 using the gripper 50 supported on the first platform 12 via the support 22, as shown in FIG. Figure 6 The machine is controlled (by appropriately varying the length of each extendable leg 16) to bring the gripper 50 into close proximity with the second part 80. The gripper 50 includes suction pads 52 which are activated when the gripper 50 is in close proximity with the second part 80 and which hold the second part 80 on the gripper 50 with sufficient force so that the second part can be lifted off the support 23 against the force of gravity.

[0132] On the surface of the gripper 50 facing the second part 80, the gripper 50 is provided with a set of three balls 54 which kinematically engage with a corresponding set of three v-grooves 84 on the surface of the second part 80 facing the gripper 50. This ensures a predictable and consistent position of the second part 80 relative to the gripper 50, which facilitates subsequent measurement steps. This also ensures that if the second part 80 slightly slides off the gripper 50, for example due to a slight loss of suction in the suction pad 52 or because the second part 80 is slightly knocked, the second part 80 will be re-attached in exactly the same relative position when properly attached again.

[0133] The conception of kinematic design includes using the least number of constraints to constrain the kinematic degrees of freedom of the body, and particularly includes avoiding overconstraint. This ensures that the body is highly repeatable relative to the holding device, and means that the body will sit on the holding device in a predictable, repeatable and known manner. This is described in "Mechanical Design of Laboratory Apparatus" (Chapman & Hall, London, 1960, 11-30 pages) by HJJ Braddick and "Exact Constraint: knowing how much is enough-and how much too much-is a key to successful design" (Mechanical Engineering, September 2009, 32-36 pages) by JG Skakoon. It should be understood that the kinematic connection in theory requires pure point contact, which is impossible in practice. On the contrary, in practice, contact will occur on a small area, which can be considered as beneficial because it disperses the load, so the term "kinematic connection" will be understood to cover pseudo-kinematic connection or quasi-kinematic connection, which has a small contact area rather than a point contact area. Even with a small contact area, the kinematic design requirements can still be considered to be met, wherein the actual contact area depends on the relevant application.

[0134] like Figure 7 As shown, after the second part 80 has been picked up to move with the first platform 12, the second part 80 is then measured using the second probe 40 to establish a reference frame for the second part 80. This is completely equivalent to the above reference Figure 3 The content described above, but this time, the measurements are related to the second part 80 and these measurements are provided by the triggering of the second probe 40, which is supported on the second (fixed) platform 14. The measurements of the second part 80 are three-dimensional point coordinate measurements. They can be collectively considered as measurements in more than three degrees of freedom, because they define both the position (three translational degrees of freedom) and the orientation (at least one rotational degree of freedom, preferably three rotational degrees of freedom) of the second part 80.

[0135] At present, the relationship between the first reference system (i.e., the reference system of the first part 70) and the second reference system (i.e., the reference system of the second part 80) has not been established, so the measurement of the first part 70 by the first probe 30 is essentially independent of the measurement of the second part 70 by the second probe 40. In other words, no relationship has been established between the corresponding measurements associated with the two different probes 30, 40. This is from Figure 5This is where the information obtained in the step shown comes into use, because the probe coincidence position determined in this step can be used to establish a connection or relationship between the first reference system and the second reference system, or to establish a common reference system. Figures 8 to 12 As shown, the relationship established between the two reference systems is used in subsequent steps to move the first part 70 and the second part 80 to a predetermined spatial relationship in the common reference system and to fix the first part 70 and the second part 80 in the predetermined spatial relationship relative to each other. This concept of establishing a relationship between the two reference systems will be described below with reference to Figures 15 to 22 Provide further explanation.

[0136] After establishing the relationship between the two reference frames, such as Figure 8 As shown, a quantity of curable adhesive 64 is applied by glue applicator 90 to the base part 60 where the second part 80 is to be placed. Fig. 9 As shown, the machine is controlled (by appropriately varying the length of each extendable leg 16) to rotate the first (movable) platform 12 relative to the second (fixed) platform 14 so that the second part 80 is properly aligned with the first part 70 in a common reference frame. Conveniently, the platforms 12, 14 are relatively rotated to provide a fixed point of rotation that coincides with, for example, a point 86 located at the bottom of the second part 80, but this is not essential.

[0137] Then, after the established relationship has been utilized to achieve the correct alignment (orientation) of the second part 80 relative to the first part 70 in the common reference frame, but not the correct position (eg, Fig.10 After that, the machine is controlled (by appropriately changing the length of each extendable leg 16) to move the first (movable) platform 12 relative to the second (fixed) platform 14 so as to position the second part 80 in the correct spatial relationship (in terms of both position and orientation) relative to the first part 70 within the common reference system, while intentionally leaving a gap between the first part 70 and the second part 80. With the uncured adhesive 64 having been applied in the correct position, the second part 80 is still held and supported by the machine relative to the first part 70, while the uncured adhesive 64 fills the gap between the first part and the second part. Fig.11 As shown, the UV source on the holder 50 applies UV rays 56 to the adhesive 64 to cure it. The second part 80 can be at least partially transparent to the UV rays (e.g., formed of a plastic material), or the UV rays can be applied around the second part 80; alternatively, a separate UV source can be provided on the support 22 or even elsewhere in the machine.

[0138] like Fig.12As shown, since the adhesive is now cured, the first platform 12 is moved away from the second platform 14, leaving the assembled product on the support 21, wherein the first part 70 and the second part 80 are now accurately fixed relative to each other on the base part 60. The final product 100 is Fig.13 , which is shown in close-up, illustrates how the described method can achieve a desired alignment between representative features 72 , 82 of the first part 70 and the second part 80 despite the presence of a defect 62 on the surface of the base part 60 .

[0139] exist Fig.14 The flowchart summarizes the above methods.

[0140] exist Figures 15 to 22 The idea of ​​using a fixed probe and a mobile probe, and establishing a relationship between two reference frames, which are measured by the two probes, is schematically summarized in . Figures 2 to 12 The representation used in Fig.15 A movable platform and a fixed platform are shown which are movable relative to each other. Both platforms are movable, of course, since it is the relative movement between the two platforms that is important, rather than the absolute positioning of one or the other; it is just that in practice it is convenient to fix one platform and move the other. The fixed platform supports or carries a probe and objects in a fixed relationship to each other in reference system A, while the movable platform supports or carries a probe and objects in a fixed relationship to each other in reference system B. It is not known at the outset how reference systems A and B relate to each other.

[0141] exist Fig.16 In the example above, the movable platform is moved so that the movable probe is in sensing relationship with a point (feature or corner) of one of the objects on the fixed platform. The coordinates of this point are recorded as a vector a1 These coordinates may be a set of machine coordinates defining the relative positions of the platforms in that particular pose (i.e., the pose that brings the movable probe tip into contact with that particular point on the object), such as the lengths of the respective extendable legs in a hexapod, or even raw readings from the transducers 17 used to derive those lengths. However, in this presentation, the coordinates are assumed to be a1 Recorded as Cartesian X, Y, Z coordinates, they are derived (transformed) from the machine coordinates based on the known geometry of the machine, so that normal vector operations are applicable.

[0142] Then, in Fig.17 In the process of sensing another point (feature or corner) of an object using a movable probe, the point coordinates are recorded as a vector a2 The movable probe is then used to sense a point (feature or surface) of another object on the fixed platform and the point is recorded as having point coordinatesa3 . Then, in Figures 19 to 21 In the process, the movable platform is moved so that the points or features of the movable objects are in a sensing relationship with the fixed probe, thereby obtaining the point coordinates respectively. b1 , b2 and b3 .

[0143] Although the coordinates of these points a1 to a3 and b1 to b3 are all measured in the same machine coordinate system (because the same set of extendable legs is controlled for all such measurements, and therefore each point coordinate is represented by a common set of machine coordinates (e.g., a set of leg lengths)), but it is still unknown how coordinates in one reference system A (or equivalent to coordinate system A) relate to coordinates in another reference system B (or equivalent to coordinate system B) in the global reference system (or coordinate system). For example, it is known how points in the same reference system are spatially related (e.g., a2 - a1 is the vector from point 1 to point 2 in reference frame A), but we do not know how points in different reference frames are related in space (e.g., b2 - a1 is not a valid consideration at this time). Fig. 22 The relationship between the reference frames is established in the steps shown.

[0144] Conceptually, the relationship is established by moving the platforms to bring the sensing points of the two probe tips (i.e., their respective centers) to the same point (i.e., the same position (coincidence) in the global coordinate space). When it is determined that this has occurred, a relationship has been established between the two reference frames A and B, allowing the various objects on the two platforms to be considered and related to each other within a common reference frame C (which can be a global reference frame or one of the two reference frames A and B).

[0145] When in Fig. 22 When the point is in the position shown, the point is recorded in reference system A as a4 , and recorded in reference frame B as b4 . But this can also be recorded in a common reference frame as a point c0 . coincidence point c0 This effectively links the two reference frames A and B together. Now, Fig. 20 The points measured in b2 It can be expressed in the common reference frame C as c0 +( b2 - b4 ),and Fig.17 The points measured in a2It can be expressed in the common reference frame C as c0 +( a2 - a4 ).

[0146] Now return again Figures 2 to 13 In these schematic diagrams, the first part 70 and the second part 80 are shown arranged side by side on the final product (see in particular Fig.13 ). The first part 70 is described as having a representative feature 72, and the second part 80 is described as having a representative feature 82, and it is described that it is important that these representative features 72, 82 are accurately positioned relative to each other in the final product. Reference will now be made to Figure 23 to Figure 25 To describe the practical application of this illustrative example.

[0147] Fig.23 A simple rearrangement of the parts 60, 70, 80 that make up the article 100 is shown. Fig.23 , the base part 60 is an elongated tube (in this example having a square cross-section) having a longitudinal axis 90, and the first part 70 and the second part 80 are arranged in a straight line along the longitudinal axis 90 of the base part (tube) 60. The first part 70 and the second part 80 are still shown schematically, but it is now apparent that the representative features 72, 82 are aligned in a direction transverse to the longitudinal axis 90. The base part (tube) 60 constitutes the first tube 60, and the article 100 also includes a second tube 66 (in this example also having a square cross-section) that slides telescopically inside the first tube 60. The first part 70 represents the above-mentioned Figure 1A A readhead of a measuring encoder of the type mentioned and a corresponding encoder scale 68 are provided on the second tube 66 .

[0148] Accordingly, the article 100 which has been manufactured by the method embodying the invention (as described above) corresponds to one of the extendable legs 16 described above, and the coordinate measuring machine 10 has been used to manufacture the extendable leg 16 for use in another such coordinate measuring machine. The second part 80 represents a bearing which allows the second tube 66 to slide within the first tube 60, wherein the representative feature 82 is the axis of the bearing. The representative feature 72 is the sensing portion of the readhead which in practice must be precisely aligned relative to the encoder scale 68 to obtain the most accurate metrological results, and the alignment of the second tube 66 within the first tube 60 is defined by the alignment of the second part (bearing) 80. Since the method has ensured that the second part (bearing) 80 is precisely aligned relative to the first part (readhead), the result is a precisely formed article (extendable leg) 100 in which the encoder scale 68 is precisely aligned with the readhead sensor 72.

[0149] Fig.24A more realistic representation of a bearing assembly 800 for use in such an article 100 is shown. The bearing assembly 800 corresponds to the second part 80. The bearing assembly 800 includes a wheel 860 supported on an axle 820, wherein the axle 820 corresponds to the representative feature 82 described above. A kinematic locating feature 840 corresponding to the v-groove 84 described above is provided on one side of the bearing assembly 800, wherein the wheel 860 protrudes most significantly from the other side of the bearing assembly 800. The kinematic locating feature 840 includes two sets of three v-grooves (i.e., six in total) to allow the bearing assembly 800 to be picked up by the gripper 50 (with three balls 54) in two different orientations (or in any one of six different orientations, since picking up in any one of three different orientations is already possible with only three rotationally symmetrical v-grooves). Fig.34 How the v-groove 840 of the bearing assembly 800 kinematically engages the ball 54 of the holder 50 is shown in greater detail.

[0150] Fig.25 It is shown how four such bearing assemblies 800 (corresponding to the four second parts 80) are assembled to the outer tube 600 (corresponding to the base part 60), these bearing assemblies being partially placed through a corresponding number of openings (or pockets) 610 formed in the outer tube 600. The flanges 830 of the bearing assemblies 800 are wider than the openings 610 and therefore cannot pass through the openings 610, but sit on and are supported by the outer tube 600 via the adhesive 64, which fills the gaps intentionally left between the bearing assemblies 800 and the outer tube 600 as described above. The wheels 860 protrude through the openings 610 when assembled, thereby being arranged along the inner tube 660 (corresponding to the base part 60). Fig.23 The inner tube 66) extends.

[0151] The inner tube 660 has a square cross-section, and there are two bearing assemblies 800 for each of two adjacent sides of the inner tube 660. The inner tube 660 is held in contact with the bearing assemblies 800 by magnetic means, wherein a magnet (not shown) is disposed in each bearing assembly 800, and the inner tube is at least partially formed of a magnetic material. Fig.25 An encoder scale 680 is disposed on the outer tube 600 (which is just blocked from view). A read head mounting block (or bracket) 700 is disposed within an opening 630 formed in the outer tube 600, and a read head 710 is mounted in the mounting block 700. The mounting block 700 corresponds to the first part 70 described above, and a sensor portion 720 of the read head corresponds to the representative feature 72. A power cable 730 provides power to the read head 710 and carries sensor signals from the read head 710.

[0152] We will now describe Fig.24 and Fig.25The method of manufacturing the specific embodiments and features shown. The method is generally similar to that described above with reference to, for example Figures 2 to 12 The description is consistent with, but with some additional features that are relevant to the specific context of the present embodiment; however, these additional features may also apply to the more general teachings above.

[0153] First, the "sleeve offset" is determined. This involves using the mobile probe 30 to measure the center of the fixed ball with the mobile platform 12 set to multiple orientations. The center of rotation of the mobile platform 12 is calculated using the ball center. The "sleeve offset" value in the controller 15 is adjusted so that when the mobile platform 12 is commanded to rotate, the center of rotation is about the mobile probe tip 32.

[0154] Next, the "probe coincidence position" is determined, which is the position of the mobile probe 30 calibrated relative to the fixed probe 40. The relationship between the mobile probe 30 and the fixed probe 40 is established by measuring one probe tip 32, 42 with the other probe tip 42, 32. This is done using touch and spherical fit to find the center point. The two probes 30, 40 are chosen to have different stiffnesses so that a known one of the two will trigger. The deflection of the stylus is assumed to be symmetric about the Z axis, so the XY position is well known; the Z axis position is less known (but well known).

[0155] The tube 600 is then measured using the mobile probe 30 to determine a coordinate system (or "Csys" for short) of the tube 600, which is denoted TubeCsys. The coordinate system TubeCsys is equivalent to the reference system of the first part as described above, and in this context, the first part comprises the tube 600 and the readhead support 700. The coordinate system TubeCsys is determined as follows:

[0156] (a) finding the axis of the cylinder of the tube 600 using touches made around the tube 600 using the mobile probe 30;

[0157] (b) determining the Z-axis position of the tube 600 using touches made with the mobile probe 30 at the front and rear of one or more recesses 610;

[0158] (c) using touches made with the moving probe 30 on the side of the readhead support 700 to fit a plane and the axis of the plane which is used to give the orientation of the tube 600; and

[0159] (d) Create a coordinate system TubeCsys for the tube 600 and readhead support 700 using the measurements from (a), (b) and (c).

[0160] Subsequently, the bearing assembly 800 is picked up. A kinematic pick-up feature consisting of three balls and a suction cup is used to pick up the bearing assembly 800 from the tray support 23. As described above, the bearing assembly 800 has six positions forming two sets of three v-shaped grooves.

[0161] The bearing assembly 800 is then measured using the fixed probe 40 to give a coordinate system of the bearing assembly 800, denoted as BearingCsys. The coordinate system BearingCsys is equivalent to the reference system of the second part as described above. The coordinate system BearingCsys is determined as follows:

[0162] (a) measuring the bearing axis 820 using touches made with a fixed probe 40 and a cylinder fitted to these measurements to determine the vector direction of the axis 820;

[0163] (b) measuring the end of shaft 820 using touches made with fixed probe 40 to find the Z center of shaft 820;

[0164] (c) measuring the plane using touches made with a fixed probe 30 to give the orientation of the bearing assembly 800; and

[0165] (d) Create a coordinate system BearingCsys for the bearing assembly 800 using the measurement results from (a), (b) and (c).

[0166] Thereafter, the center of rotation of the mobile platform 12 (from the mobile probe tip 32) is moved to the bottom of the bearing assembly 800. To accomplish this, the offset from the "coincidence probe position" to the origin of the BearingCsys is calculated, and then offset by a known distance (in this particular example, this is negative 5 mm in the Z direction) to reach the bottom of the bearing assembly 800 (i.e., at the bottom of the wheel 860); this is done in Fig.26 This offset is then added to the "sleeve offset" in the controller 15 to move the machine rotation point to the center of the bottom of the bearing assembly 800. The mobile platform 12 can now rotate on the A, B, or C axis (since the machine is non-Cartesian, the mobile platform 12 has A, B, C axes instead of X, Y, Z axes) and the center of the bottom of the bearing will remain in a fixed position.

[0167] A bead of UV adhesive is then applied in TubeCsys precisely around the associated recess 610 on the tube 600 .

[0168] A coordinate transformation is required to accurately move the bearing assembly 800 to the appropriate position (this is equivalent to the relationship between the first reference frame and the second reference frame as described above):

[0169] T=BearingCsys -1 ×TubeCsys

[0170] Where T is a 4 x 4 coordinate transformation matrix. The concept of coordinate systems and transformations between coordinate systems is well understood by those skilled in the art, but further explanation can also be found in the following literature: M. Orsag, C. Korpela, P. Oh, S. Bogdan, "Coordinate Systems and Transformations", "Aerial Manipulation" chapter (pp. 19-31), 2018, which is part of the "Advances in Industrial Control" series (print ISBN 978-3-319-61020-7; online ISBN 978-3-319-61022-1; downloaded from https: / / www.springer.com / cda / content / document / cda_downloaddocument / 9783319610207-c2.pdf). For example, some transformation matrices and operations are as follows:

[0171] 3D X-axis rotation:

[0172] 3D Z-axis rotation:

[0173] 3D Y-axis rotation:

[0174] 3D Ruler:

[0175] 3D translation: Matrix multiplication: Some pseudo code is provided below to illustrate some of the above steps that would occur in the controller 15.

[0176] Recall the probe coincidence position:

[0177] point ProbeOffset=(point)CommonData["ProbeCoincidentPosition"];

[0178] Recall the bearing assembly coordinate system:

[0179] CSYS BearingCsys=(CSYS)CommonData["FrontBearingCsys"];

[0180] Calculate the deviation between the center of the bearing point and the tip of the mobile platform probe, and translate to the bottom of the bearing: BearingPos = [BearingCsys.M.m30, BearingCsys.M.m31, BearingCsys.M.m32]; offset = ProbeOffset-BearingPos+[0,0,-5];

[0181] Among them, [0,0,-5] in the above statement is the deviation of minus 5mm on the Z axis (as mentioned above). Recall the tube coordinate system:

[0182] CSYS TubeCsys=(CSYS)CommonData["TubeCsys"];

[0183] Compute the transformation:

[0184] T=BearingCsys ^ -1*TubeCsys;

[0185] Calculate angle x, angle y, and angle z based on T.

[0186] Move the rotation point of mobile platform 12 to the "offset":

[0187] SetTipOffset(offset);

[0188] To rotate the mobile platform 12:

[0189] MoveToAngle(Angles.x, Angles.y, Angles.z, 100, 100);

[0190] Set the local coordinates to TubeCsys; this allows the machine to position in TubeCsys coordinates, and after the sleeve offset has been moved to the bottom of the bearing, the bottom of the bearing is now located:

[0191] mc.SetCsys(TubeCsys);

[0192] mc.UseLocalCsys();

[0193] The bearing assembly 800 can now be positioned relative to the tube coordinate system TubeCsys.The bearing assembly 800 is positioned so that there is a gap between the tube 600 and the bearing assembly; typically a gap of about 100 μm is suitable.

[0194] The bearing assembly 800 is then cured in place. A UV light source is mounted on the moving platform 12. The light source is used to cure the adhesive, thus freezing the bearing assembly 800 in place.

[0195] In the above-described embodiment, the second part 80 is measured using the second probe 40. In alternative embodiments, these measurements of the second part may instead be assumed or inferred from the known position and orientation of the second part relative to the first platform 12, with the aid of the repeatability and accuracy of the kinematic connection used to support the second part 80 on the first platform 12, and based on knowledge of the shape of the second part 80 (e.g., based on a CAD model of the second part 80). Accordingly, in another embodiment of the present invention, the second probe 40 is not required.

[0196] In an alternative embodiment, instead of using a fixed touch probe and a mobile touch probe, a fixed imaging camera and a mobile imaging camera may be used instead. In order to link the measurement results from one camera with the measurement results from another camera (equivalent to measuring coincidence points in the previous embodiment), key features on one camera (such as a sensor) can be imaged with another camera. In order to measure in three dimensions, the imaging camera can include three imaging sensors arranged at different corresponding angles or orientations relative to the target, or three separate imaging cameras can be used at different corresponding angles. Similarly, in another embodiment, an optical measurement device (such as a fringe-based system) can be used, in which fringes are projected onto the surface of an object or part, and in which these fringes are imaged and analyzed to obtain measurement results of the object or part.

[0197] As an extension of the above embodiment, the article 100 may be supported on a rotatable table, which is itself supported on the second platform 14. Positioning the first part 70 relative to the second part 80 may then include the step of controlling the machine to rotate the table relative to the second platform 14. This enables parts to be assembled to different sides or surfaces of the article 100 (which would otherwise be inaccessible) and effectively provides a system that has more than six axes (or degrees of freedom) to work with, i.e., the six axes (or degrees of freedom) from the coordinate measuring machine itself plus another axis of rotation provided by the rotary table. Or there may be six degrees of freedom overall, of which, for example, five are provided by the coordinate measuring machine and the sixth is provided by the rotary table. In practice, the respective parts may provide any suitable number and combination of axes. One or both of the article and the part being placed may also be connected via an articulated joint (such as a Renishaw probe head) to provide additional degrees of freedom (axis).

[0198] Similarly, the second part 80 itself may be supported on a rotatable table, wherein the rotatable table for the second part 80 is supported on the first platform 12, so that positioning the first part 70 relative to the second part 80 may then include the step of controlling the machine to rotate the rotatable table for the second part 80 relative to the first platform 12. This may be provided in addition to or in lieu of a rotatable table for the first part 70, and provides even greater manufacturing flexibility to the system.

[0199] The measurements of the first part 70 and the second part 80 are described above as measurements in more than three degrees of freedom because they define both the position (three translational degrees of freedom) and orientation (one, two or three rotational degrees of freedom) of the part (or at least its key features). Even though these measurements are in three degrees of freedom, thereby defining the position (three translational degrees of freedom) of the part but not the orientation (rotational degrees of freedom), advantages over known systems are provided. In a typical PCBA manufacturing system, the placement of components is controlled to an arbitrary degree of accuracy in only two degrees of freedom relative to the substrate (i.e., in the X-axis and Y-axis relative to the substrate) because the substrate is assumed to be planar and the absolute height of the components is not important due to the relatively large solder paste mass, which means that it is sufficient to ensure that the components are close enough to touch the solder paste.

[0200] Fig. 27 It is shown that the above process has been repeated for three second parts 80 - 1 , 80 - 2 and 80 - 3 placed on the base part 60 .

[0201] As mentioned above, the first part 70 can be conveniently considered to include the base part 60, so that Figure 3 and Figure 4 A single step of measuring a first part 70 (including a base part 60) using a first probe 30 is shown. Fig.28As shown, in an alternative arrangement, there is no "first part" per se, and there is only the base part 60, so the "first part" in this example is only the base part 60. The "first part of the article" may alternatively be referred to herein as the "existing or already assembled or already placed part of the article", and the "second part of the article" may alternatively be referred to herein as the "new or to be assembled or to be placed part of the article". Furthermore, once the second part 80-0 has been assembled onto the article 100 based on the measurement results of the base part 60, the resulting arrangement (i.e., the base part 60 and the second part 80-0) may then be considered the "first part" (or "already assembled part") for the subsequent step of adding another second part 80-1 based on the measurement results of the "first part" (i.e., the base part 60 and the second part 80-0). When placing the second part 80-1, the measurement results used may be only the measurement results of the base part 60 obtained previously, or new measurement results may be obtained for the second part 80-0 now placed, or a combination of these measurement results may be used. Similar considerations apply when placing the additional second parts 80 - 2 and 80 - 3 .

[0202] Therefore, in Fig.28 In the example shown, all parts 80-0 to 80-3 "float" above base part 60, allowing these parts 80-0 to 80-3 to be placed very accurately relative to each other (to the accuracy of a coordinate measuring machine) without being affected by any defects or irregularities in base part 60. Fig. 27 Unlike the illustrated embodiment, parts 80-0 to 80-3 are not aligned or placed relative to part 70 directly attached to base part 60, but rather all parts 80-0 to 80-3 are effectively placed in their desired relative orientations in a "free form" and are fixed / held in these relative orientations via base part 60 and fixing or support material 64 (e.g., curable adhesive or welding). This allows for a very precise and flexible manufacturing or assembly method.

[0203] Fig.29 and Fig.30 They are shown respectively Fig. 27 and Fig.28 A stacked alternative to a side-by-side arrangement, in which each new second part 80 is placed on top of the previous second part 80.

[0204] like Fig.31 As shown, as an extension of the above embodiment, the finished product can be considered as an independent module, such as Fig.31Module 100-2 is shown, which forms part of a larger whole (or complex product). Such a module 100-2 can be considered a "second part" which is itself picked up by a coordinate measuring machine and placed in a desired spatial relationship with a "first part" of an article (e.g., first part 70 and / or base part 60 and / or another such multi-part module 100-1 created in a previous series of steps) in a manner exactly similar to that described above. In this way, a more complex product 110 can be produced. Fig.31 Also shown are highly non-planar base parts 60, and complex arrangements of parts on the non-planar base parts 60, for which embodiments of the present invention are particularly well suited due to the inherent measurement accuracy of coordinate measuring machines and their ability to position parts relative to each other in more than three degrees of freedom (i.e., position and orientation).

[0205] The above embodiments use a curable adhesive as a fixing medium, but it should be noted that welding is also suitable as a fixing process. Welding is a process of joining materials by using high heat to melt the parts together (the molten material is the fixing medium) and allowing them to cool to cause fusion (the cooling process effectively activates the fixing medium). Welding is different from low-temperature joining techniques (such as brazing and soldering) that do not melt the base metal, but in embodiments of the present invention, these are also suitable techniques for the fixing process. In addition to melting the base material, filler material is usually added to the joint to form a pool of molten material (welding pool; or fixing medium), which cools to form a joint that may be stronger than the base material. Pressure can also be used in combination with heat or alone to produce welding. Many different energy sources can be used for welding, including gas flame (chemical), arc (electrical), laser, electron beam, friction and ultrasonic.

[0206] Reference has already been made to coordinate measuring machines having a plurality of length measuring (or distance measuring or displacement measuring) transducers, such as Figure 1ALength measuring transducer 17 is shown. Such length measuring transducers are used to measure relative motion in linear joints, thereby providing a measure of relative movement between two parts of the machine. The coordinate measuring machine may also include one or more rotary joints and therefore may also have one or more corresponding angle measuring transducers; for example, this is the case when the coordinate measuring machine is in the form of an articulated arm having multiple rotary joints arranged in series (similar to a machine commonly referred to as a robot arm). If such a serial kinematic coordinate measuring machine is adopted, it will be beneficial to adopt a machine architecture such as disclosed in UK patent application number 1918165.0 in order to avoid inaccuracies typically associated with the serial kinematic arrangement of axes. The various length measuring transducers and angle measuring transducers may be collectively referred to as measuring transducers. The output of these measuring transducers may be considered to be or may be used to derive machine coordinates for any particular configuration or posture of the machine (for example, Figure 1A The outputs of these measurement transducers are used in determining or reading the configuration (pose) of the machine (for measurement operations) and in setting or changing the configuration (pose) of the machine (for positioning operations).

[0207] An exemplary application of a manufacturing method embodying the present invention is described above, wherein a coordinate measuring machine is used to manufacture an extendable leg for use with another such coordinate measuring machine. Another exemplary application of a manufacturing method embodying the present invention is to manufacture a measuring probe (such as described above and as Figure 2 The probe 30 is shown with a stylus.

[0208] Such applications will refer to Fig.32 (It is similar to Fig.26 1 , but adapted for the manufacture of a stylus rather than an extendable leg. The stylus has a shaft 310 to which a stylus tip (or ball) 320 is attached; the diameter of the stylus ball 320 may be as small as 2 μm. It is desirable that the stylus tip 320 be positioned as accurately (and concentrically) as possible on the shaft 310.

[0209] The basic method is identical to that described above and therefore will not be described in detail here. Fig.32 and Fig.26 The difference is that it has a different type of gripper, which is Fig.32In the embodiment of the present invention, the suction tube 500 is in the form of an aspiration tube 500. The aspiration tube 500 has an internal passage 510 through which air can be drawn, thereby drawing the stylus tip 320 into and retaining it in a cup 520 on the end of the suction tube 500. The inner surface of the cup 520 can have kinematic features 530 to enable the ball 320 to sit in a predictable and repeatable position within the cup; for example, three protrusions (from the spherical surface of the concave part) would be suitable as kinematic features, such as Fig.32 520. This forms a tripod arrangement which is very stable and allows the ball 320 to sit predictably within the cup 520. The three point contacts create three constraints, no more and no less than what is required (thus satisfying kinematic design considerations by avoiding over-constraint). With three constraints, the ball 320 is thus constrained in three translational degrees of freedom, but is free to rotate about its center in three rotational degrees of freedom; this is not important because the ball 320 is spherically symmetric.

[0210] As in the previous embodiment, having measured the end of the rod 310 using the moving probe 30, a bead of curable adhesive (or solder paste) 640 is applied to the end of the rod 310, taking into account the measurements of the rod 310 obtained using the probe 30. The ball 320 is then precisely positioned relative to the rod 310 using the method previously described, again taking into account the measurements of the rod 310 obtained using the probe 30. Preferably, a gap is maintained between the ball 320 and the rod 310, with the machine still holding the parts relative to each other while the adhesive 640 is cured. This produces a Fig.32 The contact pin shown in the left illustration is contained within the dotted outline B.

[0211] It is also possible to partially (but not fully) cure the adhesive 640 while the relative position is maintained by the machine, for example by blowing warm air for a short time on the curable adhesive; followed by a full curing (sintering) operation, in which the machine has released the ball 320, and the partially cured adhesive 640 has sufficient strength or holding force to hold the ball 320 in a fixed position relative to the rod 310, while the part is transferred to the sintering station and sintered (fully cured). It is also possible that the adhesive 640 has sufficient holding force to hold the parts in a fixed relative position even if the adhesive is not partially cured first.

[0212] Because the orientation of the ball 320 on the rod 310 is not important in this example (since the ball is spherical), it is not necessary to leave a gap between the ball 320 and the rod 310; instead, the ball 320 can be positioned to touch the end of the rod 310, such as Fig.32As shown in the right figure contained within the dashed outline B of . What is most important in this exemplary application is that the ball 320 is positioned concentrically with the rod 310; in other words, the radial positioning of the ball 320 relative to the longitudinal axis of the rod 310 is more important than the positioning along the longitudinal axis of the rod 310.

[0213] As will be apparent from the above, it is not always necessary to leave a gap around a part being placed on an article, or even to leave no gap at all. For example, embodiments of the present application are also used to accurately assemble a part onto an article very accurately and with very close tolerances so that the part engages with a corresponding part or feature on the article without leaving any gap. For example, this may be the case where a part having a cylindrical protrusion is tightly positioned into or on an article having a cylindrical recess or hole, wherein the protrusion fits snugly and tightly within (and touches) the recess. The present invention provides a new approach to this assembly process, wherein a coordinate measuring machine is used to obtain three-dimensional measurements of features of an article (e.g., a cylindrical recess), and based on these measurements, multi-axis positioning (e.g., four-axis, five-axis, or six-axis positioning) is used to position the features of the part (e.g., a cylindrical protrusion) relative to the features of the article into a predetermined spatial relationship (in multiple degrees of freedom).

[0214] It will be appreciated that gaps may be left in some places around a placed part but not in others; for example, if the orientation of the part relative to the surface of the article, rather than the height above the surface of the article, is important, the part may be placed so as to touch the article at one (or more) points but still be held and secured in a desired orientation relative to the article. Fig.33 is shown in Fig.13 is only different in that the second part 80 is positioned to touch the base part 60 at the circled point, but remains above the base part 60 elsewhere; in other words, there is no gap around the second part 80. This means that the height of the second part 80 above the base part 60 will be affected by imperfections in the surface (such as the protrusion 62), but the orientation of the second part relative to the base part 60 (and other already placed parts, such as the first part 70) can still be controlled.

[0215] It will be appreciated that the operation of the coordinate measuring machine 10 may be controlled by a program running on the machine 10, and in particular by a program running on a coordinate measuring machine controller, such as a Figure 1A1. It will be appreciated that control of the extendable legs may be provided by a program operating on the controller 15. Such an operating program may be stored on a computer readable medium, or may be embodied in a signal such as a downloadable data signal provided from a website on the Internet, for example. The appended claims should be understood to cover the operating program itself, or as a record on a carrier, or as a signal, or in any other form.

Claims

1. A method of manufacturing an article comprising a first part already in position and a second part to be assembled to the article, the assembly of the second part to the article being part of the method, the method comprising using a coordinate measuring machine to obtain measurements of the first part and the second part, and positioning the second part in the assembled article in a predetermined spatial relationship relative to the first part based on the measurements of the first and second parts, in, The machine comprises a first platform and a second platform movable relative to each other, and the method comprises supporting the first part on the second platform and supporting the second part on the first platform, and wherein positioning the second part relative to the first part comprises controlling the machine to move the first platform and the second platform relative to each other; measuring the first part using a first probe supported on the first platform; measuring the second part using a second probe supported on the second platform; Wherein, measuring the second part using the second probe includes moving the first platform and the second platform relative to each other so that the second probe is in a sensing relationship with the second part.

2. The method of claim 1 , comprising using the measurement results of the first part to establish a first reference system for the first part; using the measurement results of the second part to establish a second reference system for the second part; establishing a relationship between the first reference system and the second reference system; and using the established relationship to move the first part and the second part to the predetermined spatial relationship in the common reference system.

3. The method of claim 2, wherein: Establishing the relationship between the first reference system and the second reference system includes determining position information associated with at least one point or feature common to both reference systems.

4. The method according to claim 2 or 3, wherein: The common reference system is the first reference system of the first part.

5. The method according to claim 2 or 3, wherein: The first reference system and the second reference system are respectively a first coordinate system and a second coordinate system, and wherein the established relationship is a coordinate transformation between the first coordinate system and the second coordinate system.

6. The method of claim 1, wherein: The predetermined spatial relationship is defined in more than three degrees of freedom.

7. The method of claim 1, wherein: Positioning the second part relative to the first part includes controlling the machine to move the second part relative to the first part in more than three degrees of freedom.

8. The method of claim 1, wherein: The measurement result is a three-dimensional measurement result.

9. The method of claim 1, wherein: The measurements are obtained by controlling the machine to move a measuring device in three or more degrees of freedom.

10. The method of claim 1, wherein: The measurement result is a coordinate measurement result.

11. The method of claim 1, wherein: The measurement result is a point coordinate measurement result.

12. The method of claim 1, wherein: The measurement results include machine coordinates or coordinates derived from machine coordinates.

13. The method of claim 1, wherein: Positioning the second part relative to the first part includes controlling the machine to adopt a series of different machine coordinates.

14. The method of claim 1, wherein: The measurements and the positioning of the second part are based on a same machine coordinate system.

15. The method of claim 1, wherein: The coordinate measuring machine comprises a plurality of measurement transducers, wherein the same plurality of measurement transducers are used for obtaining the measurements and for positioning the second part based on those measurements.

16. The method of claim 1, wherein: Positioning the second part in the predetermined spatial relationship relative to the first part includes: calculating a set of machine coordinates based on the measurement results that will position the first part and the second part in the predetermined spatial relationship; and controlling the machine to use the calculated machine coordinates.

17. The method of claim 1, comprising controlling the machine to hold the first part and the second part in the predetermined spatial relationship while performing operations to secure the first part and the second part in the predetermined spatial relationship.

18. The method of claim 17, wherein: Positioning the second part relative to the first part in the predetermined spatial relationship includes: calculating a set of machine coordinates based on the measurement results, which will position the first part and the second part in the predetermined spatial relationship; and controlling the machine to adopt the calculated machine coordinates, wherein controlling the machine to keep the first part and the second part in the predetermined spatial relationship includes controlling the machine to maintain the calculated machine coordinates.

19. The method of claim 17, wherein: The performing of the operation to fix the first part and the second part in the predetermined spatial relationship includes: applying a fixing medium, the fixing medium contacts the second part when the second part is in the predetermined spatial relationship with the first part; and activating the fixing medium to fix the first part and the second part in the predetermined spatial relationship.

20. The method of claim 19, comprising applying the securing medium prior to moving the first part and the second part into the predetermined spatial relationship, and then activating the securing medium while the first part and the second part are in the predetermined spatial relationship.

21. The method of claim 19, wherein: The securing medium is a curable adhesive, and wherein activating the securing medium includes curing the adhesive.

22. The method of claim 19, wherein: The fixing medium and the activation of the fixing medium are a result of performing a welding process.

23. The method of claim 22, wherein: The welding process is a laser welding process.

24. The method of any one of claims 19 to 23, comprising using the measurement results of the first part to establish a first reference system for the first part; using the measurement results of the second part to establish a second reference system for the second part; establishing a relationship between the first reference system and the second reference system; using the established relationship to move the first part and the second part to the predetermined spatial relationship in the common reference system; and using the established relationship to determine a location to apply the securing medium.

25. The method of claim 1, wherein: When the first part and the second part are in the predetermined spatial relationship, the second part is not in direct contact with any other part of the article.

26. The method of claim 1 including leaving a gap between the second part and any other part of the article when in the predetermined spatial relationship.

27. The method of claim 19, wherein: When the first part and the second part are in the predetermined spatial relationship, the second part is not in direct contact with any other part of the article, and the method includes leaving a gap between the second part and any other part of the article when in the predetermined spatial relationship, wherein the gap is at least partially bridged by the applied fixing medium.

28. The method of claim 1, wherein: Supporting the second part on the first platform includes picking up the second part using a picking device supported on the first platform.

29. The method of claim 28, wherein: The picking device includes a gripper.

30. The method of claim 28 or 29, wherein: When the second part is supported by the first platform, the second part is kinematically or pseudo-kinematically coupled to the pickup device via a set of kinematic or pseudo-kinematic features provided on the pickup device.

31. The method of claim 30, wherein: The kinematic or pseudo-kinematic features provided on the pickup device engage with a corresponding set of kinematic or pseudo-kinematic features provided on the second part.

32. The method of claim 31 , comprising obtaining the measurement results of the second part using a model of the second part and knowledge of the position of the second part relative to the first platform by means of a kinematic connection, rather than using the coordinate measuring machine to obtain the measurement results of the second part.

33. The method of claim 1, wherein: The first platform is a movable platform and the second platform is a fixed platform.

34. The method of claim 1, wherein: Measuring the first part using the first probe includes moving the first platform and the second platform relative to each other to place the first probe in a sensing relationship with the first part.

35. The method of claim 1, wherein: Measuring the first part with the first probe includes moving the first platform and the second platform relative to each other in more than three degrees of freedom.

36. The method of claim 35, wherein: The first probe is a movable probe.

37. The method of claim 1, wherein: The first probe is a contact probe.

38. The method of claim 37, wherein: The first probe is a touch trigger probe.

39. The method of claim 37, wherein: The first probe is an analog probe or a scanning probe, or a camera-based probe having at least one imaging sensor arranged in different respective orientations relative to each other.

40. The method of claim 1, wherein: Measuring the second part with the second probe includes moving the first platform and the second platform relative to each other in more than three degrees of freedom.

41. The method of claim 33, wherein: The second probe is an immobilized probe.

42. The method of claim 1, wherein: The second probe is a contact probe.

43. The method of claim 42, wherein: The second probe is a touch trigger probe.

44. The method of claim 42, wherein: The second probe is an analog probe or a scanning probe, or a camera-based probe having at least one imaging sensor arranged in different respective orientations relative to each other.

45. The method of claim 2, comprising using the second probe to measure the first probe and / or using the first probe to measure the second probe to establish a relationship between the first reference system and the second reference system.

46. ​​The method of claim 45, wherein: Measuring the first probe with the second probe and / or measuring the second probe with the first probe includes moving the first platform and the second platform relative to each other so that the first probe and the second probe are in sensing relationship with each other.

47. The method of claim 3, wherein: The first probe and the second probe each include a stylus tip, and wherein the common point is a center point of the stylus tips of the first probe and the second probe when the first platform and the second platform are in positions relative to each other that will cause the stylus tips of the first probe and the second probe to be in the same position.

48. The method of claim 47, comprising: When one of the first probe and the second probe is a touch trigger probe and the other of the first probe and the second probe is a scanning probe or an analog probe, an extrapolation-to-zero technique is used to measure or characterize the surface of the stylus tip of the touch trigger probe and determine the center point of the stylus tip therefrom.

49. The method of claim 1, comprising supporting the second part on a rotatable table, wherein: The rotatable table is supported on the first platform, and wherein positioning the first part relative to the second part includes controlling the machine to rotate the rotatable table relative to the first platform.

50. The method of claim 1, comprising supporting the article on a rotatable table, wherein: The rotatable table is supported on the second platform, and wherein positioning the first part relative to the second part includes controlling the machine to rotate the table relative to the second platform.

51. The method of claim 1, wherein: The first platform and the second platform are moved relative to each other in more than three degrees of freedom to position the second part relative to the first part.

52. The method of claim 1, wherein: The first part is a support or substrate part of the article.

53. The method of claim 1, wherein: The first part and the second part are operative parts of the article having a function in use of the article, rather than being mere reference features or datums having a function only during manufacture of the article.

54. The method of claim 1, wherein: These parts are parts of the final product that are functionally and / or mechanically and / or optically related to one another.

55. The method of claim 1, wherein: In the resulting article the second part is supported on the first part.

56. The method of claim 19, wherein: In the obtained product, the second part is supported on the first part, and the fixing medium is arranged between the first part and the second part.

57. The method of claim 1, wherein: In the resulting article the first part and the second part are supported on a base part of the article.

58. The method of claim 19, wherein: In the resulting article, the first part and the second part are supported on a base part of the article, wherein the fixing medium is arranged between the second part and the base part.

59. The method of claim 1, wherein: The first part comprises a base part or substrate of the article.

60. The method of claim 1, wherein: The first part includes a feature of the article.

61. The method of claim 1, comprising using a measurement device other than a probe to obtain the measurements.

62. The method of claim 1, wherein: Obtaining measurements of the part includes obtaining measurements of one or more features of the part.

63. The method of claim 1, wherein: Obtaining measurements of the part includes obtaining measurements of one or more discrete points on a surface of the part.

64. The method of claim 1, wherein: The coordinate measuring machine is a machine adapted to measure geometrical features of a physical object in three dimensions by sensing discrete points on the surface of the object using sensing means.

65. The method of claim 1, wherein: The coordinate measuring machine is a machine having a coordinate measuring device for measuring the coordinates of points on the surface of an object.

66. The method of claim 1, wherein: The coordinate measuring machine is a non-Cartesian coordinate measuring machine.

67. The method of claim 1, wherein: The coordinate measuring machine is a parallel-kinematic coordinate measuring machine.

68. The method of claim 1, wherein: The coordinate measuring machine includes a plurality of extendable legs.

69. The method of claim 1, wherein: The coordinate measuring machine is a hexapod coordinate measuring machine comprising six extendable legs.

70. The method of claim 68 or 69, wherein: The machine coordinates of the coordinate measuring machine include values ​​respectively associated with the lengths of the plurality of extendable legs.

71. The method of claim 68 or 69, wherein: The coordinate measuring machine comprises a plurality of measuring transducers, wherein the same plurality of measuring transducers are used for obtaining the measurements and for positioning the second part based on those measurements, wherein the plurality of measuring transducers are respectively associated with the plurality of extendable legs.

72. The method of claim 1, wherein: The second part and the measuring device for obtaining the measurement of the first part are simultaneously supported on a common platform of the machine, the platform being moved when measuring the first part and when positioning the second part.

73. The method of claim 1, comprising repeating the method for one or more additional second parts of the article, wherein: In each repeated execution of the method, the first part is any one or more parts of the article resulting from any previous execution of the method.

74. The method of claim 73, wherein: The first part in at least one of the iterations of the method includes at least one second part from any previous iteration of the method.

75. The method of claim 73 or 74, wherein: Using the machine to obtain measurements of the first part in at least one of the iterations of the method is equivalent to using measurements of that first part obtained in a previous iteration of the method.

76. The method of claim 1, wherein: The or each second part forms part of either: (a) a bearing assembly for an extendable leg of a coordinate positioning machine; or (b) a ball or tip of a stylus for a measurement probe.

77. The method of claim 1, wherein: The first part forms part of one of: (a) a readhead or readhead holder for an extendable leg of a coordinate positioning machine; or (b) a stem of a stylus for a measurement probe.

78. The method of claim 7, wherein: Positioning the second part relative to the first part comprises controlling the machine to move the second part relative to the first part in four degrees of freedom, or in five degrees of freedom, or in six degrees of freedom.

79. The method of claim 9, wherein: The measurements are obtained by controlling the machine to move the measuring device in four degrees of freedom, in five degrees of freedom, or in six degrees of freedom.

80. The method of claim 35, wherein: Measuring the first part using the first probe includes moving the first platform and the second platform relative to each other in four degrees of freedom, five degrees of freedom, or six degrees of freedom.

81. The method of claim 37, wherein: The first probe is a touch probe or a tactile probe.

82. The method of claim 39, wherein: The camera-based probe has two or three imaging sensors arranged in different respective orientations relative to each other.

83. The method of claim 40, wherein: Measuring the second part with the second probe includes moving the first platform and the second platform relative to each other in four degrees of freedom, five degrees of freedom, or six degrees of freedom.

84. The method of claim 42, wherein: The second probe is a tactile probe.

85. The method of claim 44, wherein: The camera-based probe has two or three imaging sensors arranged in different respective orientations relative to each other.

86. The method of claim 60, wherein: The features of the article are integral features of the article.

87. The method of claim 86, wherein: The integral feature is a geometric feature formed in the surface of the article.

88. The method of claim 64, wherein: The sensing device is a probe.

89. The method of claim 65, wherein: The coordinate measuring device is a probe.

90. The method of claim 72, wherein: The measuring device is a probe.

91. The method of claim 2, wherein: Establishing the relationship between the first reference system and the second reference system includes determining position information associated with at least one point or feature that coincides in the two reference systems.

92. The method of claim 91, wherein: The first probe and the second probe each include a stylus tip, and wherein the coincidence point is a center point of the stylus tips of the first probe and the second probe when the first platform and the second platform are in positions relative to each other that will cause the stylus tips of the first probe and the second probe to be in the same position.

93. A method of manufacturing an article having a plurality of parts, the method comprising: for a first selected part of the plurality of parts, performing at least the measuring step and the positioning step of the method of any one of claims 1 to 92 to position the first selected part on the article, and For each subsequently selected part of the plurality of parts, at least the positioning step of the method as described in any one of claims 1 to 92 is performed to position the subsequently selected part on the article, wherein the positioning step uses measurement results obtained when performing the method on the current and / or any previously selected part.

94. The method of claim 93, wherein: For each subsequently selected part of the plurality of parts, the measuring step further comprises performing the method of any one of claims 1 to 92.

95. The method of claim 93, wherein: At least one of the plurality of parts is a module made from a plurality of other parts of the plurality of parts during the course of performing the method.

96. A manufacturing system comprising a coordinate measuring machine configured to perform the method of any one of claims 1 to 95.

97. Manufacturing equipment comprising a coordinate measuring machine configured to perform the method of any one of claims 1 to 95.

98. A computer program product comprising a computer program which, when executed by a processor of a coordinate measuring machine, causes the coordinate measuring machine to perform the method of any one of claims 1 to 95.

99. A computer readable medium having stored therein computer program instructions which, when executed by a processor, control a coordinate measuring machine to perform the method of any one of claims 1 to 95.

Images