CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/264,453, filed December 8, 2015, which is incorporated by reference in its entirety.

BACKGROUND

L Technical Field

Embodiments discussed herein relate generally to machine vision inspection systems for simultaneous measurement and/or inspection of multiple sides of a part along multiple axes. More specifically, embodiments discussed herein allow for the rapid inspection of multiple sides of a part, and allow that part to be placed on a stationary fixture while sensors mounted on a movable bridge or gantry are moved in relation to the part, removing the need to apply pressure to the part itself to hold it stationary while it is inspected.

II. Discussion of the Related Art

In order to visually inspect parts that are larger than the field of view of a camera, or in order to inspect parts using a laser, contact probe or other sensor, it is customary to fixedly secure the part (e.g., using a clamp, vice, etc.) in a rigid nest or fixture on a stage of a coordinate measurement machine and then move the stage with respect to the sensor (e.g., the camera, contact probe, laser, etc.) on one to five axes of motion. Encoders coupled to the stage provide information describing the position of the stage - and, thus, the part - relative to the sensor. After a reading is made with the part at one position (e.g., by contacting the part with a contact probe, by capturing imagery of the part within the field of view of a camera, etc.), the part is moved to a new position and a new reading is made. The process of making readings and moving the part (i.e., the inspection process) is repeated until the overall size of the part can be determined.

Coordinate measurement machines often utilize a bridge (also known as a "gantry") design for the purpose of mounting one or more sensors. In order to increase the rigidity of the bridge and ensure that the sensor and the part remain stable in relation to each other,

conventional bridge designs fully or partially wraps around the stage that holds the part, in a so- called "ring-bridge" design. With such a design, the bridge is ordinarily fixed, with the stage moving in relation to the sensors mounted on the ring-style bridge. Sometimes, a sensor mounted on the gantry or bridge is capable of limited motion along one axis, but the primary means of moving the part is accomplished by moving the stage with the part to be measured being fixed to it. For example, a conventional ring bridge design consists of a ring bridge with a single touch, camera, or laser sensor mounted on a Z axis motion axis that, in turn, is mounted on the bridge.

A related design intended for the mounting of maskless exposure systems for printed circuit board applications utilizes an upper bridge to mount one sensor or exposure system above a part, and then places a lower bridge underneath the part, which has an additional sensor or exposure system mounted to it. In this design, the upper bridge and the lower bridge are mechanically independent of one another, and an auto-calibration process must be performed to align the sensors mounted on these bridges before moving a sensor mounted on one stage relative a sensor mounted on another stage.

Generally, however, a problem exists in that the parts to be inspected can be very thin and flexible, and securing such parts within a rigid nest or fixture can mechanically deform the parts. For example, if one desires to measure the flatness of a thin, flat object, then one must put some pressure on it to sufficiently secure it within a nest or fixture on a stage to prevent the part from shifting as the stage is moved during the inspection process. However, the pressure ultimately exerted on the part to secure it within the nest or fixture typically results in mechanical deformation of the part.

SUMMARY

An embodiment of the present invention can be broadly characterized as a manufacturing system for performing an operation on a workpiece, wherein the system includes: a stationary workpiece support configured to support a workpiece; a rigid mechanical inspection element support partially encircling the workpiece support with a first inspection element for performing an operation from a first side of the workpiece and a second inspection element for performing an operation from a second side of the workpiece; and a motion system coupled to the inspection element support, wherein the motion system is configured to move said inspection element support in at least one axis relative to the workpiece support.

Another embodiment of the present invention can be more narrowly characterized as including a C-shaped bridge or gantry with sensors mounted on the upper and lower arms, and a fixed shelf, which does not move while the workpiece is on it during the inspection process, although it may move to load and unload the workpiece. Once the inspection process begins, the part remains still and then the sensors from above, below or both, are moved about the workpiece. They can be moved along the x, y, and z axes. The sensors themselves can be rotated on their own axis of motion as well. The encoders can read, much like the prior art, where the sensors and encoder positions are compared and an overall measurement is made. The rigid structure that holds the sensors is in the form of a partial ring bridge, or "C" shaped bridge so that it can go above and below the fixed shelf, leaving access for humans to load and unload that shelf, for that shelf to move out of the way and come back in as parts can be changed or for a robotic pick and place or other automation component to load and unload that shelf as it sits there. Embodiments described herein provide these advantages because the shelf on which the workpiece is placed remains stationary during inspection, there is no need to place pressure on the workpiece to hold it stationary. This allows the inspection and measurement of a variety of workpiece that may be too thin, too fragile or otherwise subject to distortion to allow the effective use of other coordinate measuring machines.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages will become more readily understood and appreciated through reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 illustrates a side plan view of an inspection machine according to one embodiment of the present invention.

FIG. 2 illustrates a front plan view of the inspection machine shown in FIG. 1.

DETAILED DESCRIPTION

Example embodiments are described herein with reference to the accompanying drawings. Unless otherwise expressly stated, in the drawings the sizes, positions, etc., of components, features, elements, etc., as well as any distances therebetween, are not necessarily to scale, but are exaggerated for clarity. In the drawings, like numbers refer to like elements throughout. Thus, the same or similar numbers may be described with reference to other drawings even if they are neither mentioned nor described in the corresponding drawing. Also, even elements that are not denoted by reference numbers may be described with reference to other drawings.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be recognized that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Unless otherwise specified, a range of values, when recited, includes both the upper and lower limits of the range, as well as any sub-ranges therebetween. Unless indicated otherwise, terms such as "first," "second," etc., are only used to distinguish one element from another. For example, one node could be termed a "first node" and similarly, another node could be termed a "second node", or vice versa.

Unless indicated otherwise, the term "about," "thereabout," etc., means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. Spatially relative terms, such as "below," "beneath," "lower," "above," and "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature, as illustrated in the FIGS. It should be recognized that the spatially relative terms are intended to encompass different orientations in addition to the orientation depicted in the FIGS. For example, if an object in the FIGS, is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. An object may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may be interpreted accordingly. Referring to FIGS. l and 2, an inspection system, such as inspection system 100, is mounted on a base 102 and includes a workpiece support 104, a riser 106, a motion system 108, a inspection element support 110, a first inspection element 112, a second inspection element 114 and a system support 116. The base 102 may be provided as a suitably massive and rigid structure (e.g., granite block, etc.) for vibrationally isolating the components of the inspection system 100 from the external environment. Although FIGS. 1 and 2 illustrate an embodiment in which the inspection system 100 includes two risers 106, it will be appreciated that one riser 106 may be omitted, or that the inspection system 100 can include more than two risers 106.

The workpiece support 104 is coupled to the risers 106 which, in turn, are arranged on the system support 116. The workpiece support 104 may be provided as a shelf, chuck, plate, etc., configured to support one or more workpieces. An exemplarily workpiece is shown at 101. In one embodiment, the workpiece support 104 is configured to support a workpiece 101 such that the workpiece 101 can be inspected from above the workpiece support 104 (e.g., by the first inspection element 112) and from below the workpiece support 104 (e.g., by the second inspection element 114). Accordingly, at least a portion of the workpiece support 104 supporting the workpiece 101 can be formed of a material that is transparent to a wavelength of light to which the second inspection element 114 is sensitive (i.e., if the second inspection element 114 is includes an optical sensor such as a line scan camera, a matrix array camera, etc.). Additionally, or alternatively, the workpiece support 104 may include one or more openings exposing the workpiece 101 for inspection by the second inspection element 114.

Optionally, one or more fixture nests (each also referred to herein as a "fixture") may be integrally formed with the workpiece support 104, or may be detachably coupled to the workpiece support 104. Each fixture nest may be configured to hold, retain or otherwise maintain a workpiece 101 in a predetermined spatial orientation and/or location within the inspection system 100. The workpiece support 104 may be configured to accommodate a variety of fixture nests having different configurations (e.g., to hold workpieces having different physical configurations, made of different materials, or the like or any combination thereof). Thus, when detachably coupled to the workpiece support 104, different fixture nests may be interchanged into the inspection system 100, enhancing the utility of the inspection system 100. To the extent that a fixture nest is either integrally formed with the workpiece support 104 or is temporarily coupled to the workpiece support 104, the fixture nest may be considered a part of the workpiece support 104. In one embodiment, a fixture nest may be formed of a material that is transparent to a wavelength of light to which the second inspection element 114 is sensitive (e.g., as discussed above). In another embodiment, fixture nest may include one or more openings exposing the workpiece 101 for inspection by the second inspection element 114.

Coupled to the risers 106, the workpiece support 104 is stationary (or at least

substantially stationary) within the inspection system 100 (e.g., with respect to the inspection element support 110. Since the workpiece support 104 is stationary, any workpiece supported by the workpiece support 104 or a fixture nest does not move (or does not move in a significant manner) during an inspection process carried out using the inspection system. Accordingly, a workpiece 101 can remain suitably stationary during the inspection process if the workpiece 101 is simply resting on the workpiece support 104 (or on or within a fixture nest), or if the workpiece 101 is held by the workpiece support 104 (or a fixture nest) at relatively few places on the workpiece 101, at a relatively small area on the workpiece 101, with a relatively light force, or the like or any combination thereof.

The motion system 108 may include a first motion stage 108a and a second motion stage 108b and be arranged on the system support 116, below the workpiece support 104. The second motion stage 108b is arranged on the system support 116 and may be provided as a Y-axis stage (e.g., capable of imparting movement along a Y-axis). The first motion system 108a is carried by the second motion system 108b and may be provided as an X-axis stage (e.g., capable of imparting movement along an X-axis, which is orthogonal to the Y-axis). Although FIGS. 1 and 2 illustrate an embodiment in which the motion system 108 includes two motion stages, it will be appreciated that the motion system 108 may include only a single motion stage (e.g., the first motion stage 108a, the second motion stage 108b, or a different stage altogether), or more than two motion stages. Although FIGS. 1 and 2 illustrate an embodiment in which the motion system 108 includes motion stages configured to impart movement along two orthogonal axes, it will be appreciated that the motion system 108 may include motion stages configured to impart movement along a common axis. Further, although the motion system 108 has been described as including only linear motion stages, it will be appreciated that the motion system 108 may, additionally or alternatively, include one or more rotary stages (e.g., configured to impart movement about an axis parallel to the X-axis, the Y-axis, a Z-axis orthogonal to the X- and Y- axes, or the like or any combination thereof). The inspection element support 110 is coupled to the motion system 108 and is moveable relative to the workpiece support 104. For example, in the illustrated embodiment, the inspection element support 110 is coupled to the first motion stage 108a and, so, is moveable along the X- and Y-axes relative to the workpiece support 104. In one embodiment, the inspection element support 110 is provided as a partial ring-type bridge or a "C-bridge" that extends from the motion system 108 (e.g., at a location below the workpiece support 104) and terminates at an end located above the workpiece support 104. As exemplarily illustrated, the inspection element support 110 extends partially around the workpiece support 104, thus allowing access to the workpiece support 104, fixture nest, etc., facilitating access for either a human operator or a robot (e.g., a pick-and-place machine) to load and unload workpieces to be inspected using the inspection system 100. Although the illustrated embodiment shows the inspection element support 110 provided as a single, unitary structure having a fixed shape, it will be appreciated that the inspection element support 110 may be provided as a articulated (e.g., jointed) structure having segments (e.g., joined together in series) that may be selectively oriented relative to one another and subsequently locked in place (e.g., at joints thereof) in any suitable or desired manner.

The first inspection element 112 may be coupled to the terminal end of the inspection element support 110, above the workpiece support 104. Generally, the inspection element support 110 is configured to suspend the first inspection element 112 a sufficient distance above the workpiece support 104 such that, when a workpiece 101 is supported by the workpiece support 104, the first inspection element 112 can move relative to the workpiece 101 without undesirably damaging or moving the workpiece 101. The inspection element support 110 is provided as a suitably rigid structure such that, if the inspection element support 110 is moved relative to the workpiece support 104, the first inspection element 112 will remain at least stationary (or at least substantially stationary) relative to the inspection element support 110, the first motion stage 108a, the second inspection element 114, or the like or any combination thereof. Although FIGS. 1 and 2 illustrate wherein only one sensor (i.e., the first inspection element 112) is coupled to the terminal end of the inspection element support 110, it will be appreciated that multiple sensors may be coupled to the terminal end of the inspection element support 110. In the illustrated embodiment, the second inspection element 114 is coupled to the motion system 108 (e.g., at the first motion stage 108a), and is aligned with the first inspection element 112 (e.g., along the Z-axis). In another embodiment, however, the second inspection element 114 is offset from the first inspection element 112 along the Z-axis. In yet another embodiment, the second inspection element 114 is coupled to the inspection element support 110. In the event that the second inspection element 114 is coupled to the inspection element support 112, the inspection element support 110 may, optionally, extend further below the workpiece support 104 such that the second inspection element 114 can be aligned with the first inspection element 112 (e.g., along the Z-axis). Although FIGS. 1 and 2 illustrate wherein only one sensor (i.e., the second inspection element 112) is coupled to the motion system 108, it will be appreciated that multiple sensors may be coupled to the motion system 108 (e.g., at the first motion stage 108a), to the inspection element support 110, or the like or any combination thereof.

In one embodiment, inspection elements such as the first inspection element 112 and the second inspection element 114 are immovable (or at least substantially immovable) relative to the structure(s) to which they are coupled. For example, the first inspection element 112 is at least substantially immovable relative to the inspection element support 110. Likewise, the second inspection element 114 may be at least substantially immovable relative to the first motion stage 108a. In another embodiment, however, an inspection element may be moveably coupled to the inspection element support 110 or to the first motion stage 108a. For example, the inspection system 100 may include a motion stage (e.g., a Z-axis stage, configured to impart movement along the Z-axis) coupled between the inspection element support 110 and the first inspection element 112. In another example, the inspection system 100 may include a motion stage (e.g., a Z-axis stage) coupled between the first motion stage 108a and the second inspection element 114. Inclusion of one or more Z-axis stages as discussed above may facilitate fine- tuning of the inspection system 100 to inspect the workpiece 101, facilitate optimal placement of inspection elements relative to the workpiece 101, facilitate focusing of an inspection element such as a camera, or the like or any combination thereof.

Any of the inspection elements mentioned herein (e.g., including the first inspection element 112 and the second inspection element 114) may be provided as a camera, an illumination light source, a proximity sensor, a distance sensor, a confocal microscope, or the like or any combination thereof. Examples of cameras includes digital cameras having an image sensor array formed of a matrix-array of pixel sensors, having an image sensor array formed of a line-array of pixel sensors, infrared cameras, hyperspectral cameras, plenoptic cameras, or the like or any combination thereof. Examples of illumination light sources include infrared light sources, visible-light light sources, light emitting diodes (LEDs), structured light sources, or the like or any combination thereof. Examples of proximity sensors or distance sensors include infrared proximity sensors, ultrasonic or proximity or distance sensors, laser rangefinders, triangulation lasers, touch probes, or the like or any combination thereof. In one embodiment, inspection elements arranged above and below the workpiece support 104 are the same. In another embodiment, at least one inspection element arranged above the workpiece support 104 is different from at least one inspection element arranged below the workpiece support 104. If the first inspection element 112 and the second inspection element 114 are provided as a distance sensor such as a triangulation laser, and if the first inspection element 112 and the second inspection element 114 are aligned relative to one another in the Z-axis, the thickness of the workpiece 101 (i.e., as measured along the Z-axis) can be measured. In one embodiment, one of the first inspection element 112 or the second inspection element 114 is provided is provided as a camera, and the other of the second inspection element 114 or the first inspection element 112 is provided as an illumination light source.

Although not shown, the inspection system 100 may include a controller

communicatively coupled (e.g., over one or more wired or wireless communications links to one or more of the motion system 108, the first inspection element 112 and the second inspection system 114. Generally, the controller includes one or more processors configured to generate the aforementioned control signals upon executing instructions. A processor can be provided as a programmable processor (e.g., including one or more general purpose computer processors, microprocessors, digital signal processors, or the like or any combination thereof) configured to execute the instructions. Instructions executable by the processor(s) may be implemented software, firmware, etc., or in any suitable form of circuitry including programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), field-programmable object arrays (FPOAs), application- specific integrated circuits (ASICs) - including digital, analog and mixed analog/digital circuitry - or the like, or any combination thereof. Execution of instructions can be performed on one processor, distributed among processors, made parallel across processors within a device or across a network of devices, or the like or any combination thereof. In one embodiment, the controller includes tangible media such as computer memory, which is accessible (e.g., via one or more wired or wireless communications links) by the processor. As used herein, "computer memory" includes magnetic media (e.g., magnetic tape, hard disk drive, etc.), optical discs, volatile or non-volatile semiconductor memory (e.g., RAM, ROM, NAND- type flash memory, NOR-type flash memory, SONOS memory, etc.), etc., and may be accessed locally, remotely (e.g., across a network), or a combination thereof. Generally, the instructions may be stored as computer software (e.g., executable code, files, instructions, etc., library files, etc.), which can be readily authored by artisans, from the descriptions provided herein, e.g., written in C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, etc. Computer software is commonly stored in one or more data structures conveyed by computer memory.

Although not shown, one or more drivers (e.g., RF drivers, servo drivers, line drivers, power sources, etc.) can be communicatively coupled to an input of one or more components such as the first motion stage 108a and the second motion stage 108b. In one embodiment, each driver typically includes an input to which the controller is communicatively coupled and the controller is thus operative to generate one or more control signals which can be transmitted to the input(s) of one or more drivers associated with the first motion stage 108a and the second motion stage 108b.

In one embodiment, inspection recipes (e.g., instructions describing movement to be imparted by one or more motion stages of the motion system 108, operations to be performed by one or more of the inspection elements, or the like or any combination thereof) may be stored at the controller (e.g., within the computer memory, etc.). In one embodiment, the inspection system can be operated to collect feature positions or defect locations on the workpiece 101, and then provide a report on the quality of the workpiece 101, and an instruction recipe can include logical operations such that certain operations (e.g., motion, inspection, etc.) are performed based on the results of a previously-performed operation, based on the results of collected feature positions, based on the results of collected defect locations, or the like or any combination thereof. For example, if a camera (e.g., provided as an inspection element coupled to the terminal end of the inspection element support 110) optically detects a possible defect, a logical branch of the inspection recipe might instruct the inspection system 100 to cause a triangulation laser (e.g., also provided as an additional inspection element coupled to the terminal end of the inspection element support 110) and the possible defect to be moved relative to one another (e.g., by driving one or more of the first motion stage 108a and the second motion stage 108b to determine the height of the possible defect. Pass/fail criteria might be based on a laser measurement, but all areas of the possible defect might be identified using the camera. It's possible that the results of an operation on one side of the workpiece 101 can call for an operation on the other side of the workpiece 101 (e.g., to drive the motion system 108 to move an inspection element to a suspect location relative to the workpiece 101, etc.).

In one embodiment, one or more calibration artifacts can be placed in or on either the workpiece support or the fixture nest. One or more calibration artifacts such as a thickness standard, a reticle to a test pattern, a step gauge, a gauge block, a length bar, ball plate, hole plate, test piece, or the like or any combination thereof, can be used to calibrate the first inspection element 112, the second inspection element 114, or any combination thereof. If a calibration artifact such as a test pattern is clear and relatively thin, cameras from both above and below the shelf can use the same artifact to obtain concentric alignment between the two cameras. An advantage of having the artifacts always available to re-calibrate the sensors is that if the system is used in an area where temperature variations might otherwise perturb the measurements the system can take frequent "self-check" calibrations as part of the inspection recipe.

For workpieces 101 that require inspection along their edges (e.g., a printed circuit board with an edge facing connector, etc.), a 45-degree mirror mounted on the fixture nest or on the shelf can be used to allow an inspection element to inspect the edges of the workpiece 101. Both a laser beam and the optical path of a lens can be turned ninety degrees this way. For features that need inspection, which are not facing either directly up or directly out from the workpiece 101, the one or more of the inspection elements can be mounted on a rotating axis (e.g., to adjust the angle of attack of the inspection element to accommodate the workpiece feature).

In one embodiment, one or more manufacturing devices may be coupled to the inspection element support 110, to the motion system 108, etc., (e.g., in the manner that the aforementioned inspection elements are coupled to the inspection element support 110, to the motion system 108, etc.). Examples of manufacturing devices that may be used include a laser system (e.g., to mark, drill, cut, weld or otherwise machine the workpiece 101), a mechanical machining system (e.g., a mechanical drill, router, etc.), a dispensing system, or the like or any combination thereof. The foregoing is illustrative of embodiments and examples of the invention, and is not to be construed as limiting thereof. Although a few specific embodiments and examples have been described with reference to the drawings, those skilled in the art will readily appreciate that many modifications to the disclosed embodiments and examples, as well as other embodiments, are possible without materially departing from the novel teachings and advantages of the invention. Accordingly, all such modifications are intended to be included within the scope of the invention as defined in the claims. For example, skilled persons will appreciate that the subject matter of any sentence, paragraph, example or embodiment can be combined with subject matter of some or all of the other sentences, paragraphs, examples or embodiments, except where such combinations are mutually exclusive. The scope of the present invention should, therefore, be determined by the following claims, with equivalents of the claims to be included therein.