The present disclosure relates to methods and devices for use in the automated assembly and/or preparation of wax molds usable in lost wax casting.
The casting of metal objects using a lost wax process is an ancient and well-known process that is still widely used in areas including the manufacture of jewelry, dentistry, the arts, and industry. When used for industry, lost wax casting may also be referred to as investment casting, and is commonly used in engineering and manufacturing applications to create precision metal parts.
Traditionally, lost wax casting is a manual process; the wax molds are assembled by hand, which is a labor-intensive, time-consuming operation and allows for a high degree of variation in part placement. An operator would gather all of the necessary parts and then start the assembly process. Using templates, hot irons, melted wax and other methods they would assemble the molds’ multiple parts following the work standards for the specific wax mold. During the assembly process, an operator would have to place each part in its specific location, customizing multiple parts to fit by trimming and melting to size, then placing them in the desired location.
To verify that each part on the wax mold meets the finished product’s quality requirement the wax mold is then transferred to an inspection station. At the inspection station, the operator manually verifies each part and its supporting structures position by sliding a template over each part/structure one at a time, rotating the wax mold’s assembly to verify each location.
The steps in lost wax casting include those found in
The shell is then heated and wax is removed (de-waxing). The next step in the process is normally metal pouring, but it sometimes is necessary to perform additional preparation of the shell prior to metal pouring (shell prep), which can include the intentional fracturing and removal of portions of the ceramic shell.
Attempts to automate this process requires precise accuracy of its component parts and each step of the process, including placement and welding of the mold parts, as well as measurements and inspection of the mold.
The process of manually assembling a completed wax mold, one part at a time, using hand tools to melt and assemble wax parts allows for a high degree of variation in the parts location. Manual assembly leads to increased rework on the final product due to it not passing the quality inspection requirements. Variations in operator methods, assembly times, temperatures, parts, etc. can all influence the quality and reliability of the finished assembled mold.
Manually measuring these parts defeats the purpose of saving labor by automation. Some parts are very difficult to precisely measure sufficiently to allow automated assembly. For translucent wax and plastic materials, identification of the exact edge has been difficult for most light and laser based measurement devices. Using a visible spectrum laser proved capable to provide the data in a digital format to allow automated assembly, processing and inspection of the materials.
Automation can include the use of robot applications. A robotic application requires pre-programed destination positions or teach points that are stored in the robot controller and the robot moves to them in a user defined sequence. These sequences can be used to create any number of process in which a robot manipulates a work piece, for instance, a wax mold. When manipulating work pieces that have inconsistent geometry a difference can occur in the pre-programed position and the actual part position.
When the difference in the pre-programed position and the actual part position occurs the programmer must re-program the teach point so that it matches the new part position. This can occur multiple times throughout a run creating significant down time and potential for a robot crash or mispick.
According to aspects of the present disclosure, there is provided in a first aspect a method and system for automating the assembly method for building a wax mold. The automation uses multiple inverted 6-axis robots to pick parts from their defined location(s). The automated assembly cell uses a laser displacement system to measure the main sub-assemblies location and adjusts its position by use of custom software.
According to aspects of the present disclosure, there is provided a method and system for using a visible spectrum laser to accurately measure translucent wax and plastic parts for orientation, processing, assembly and inspection of assembled products. In another aspect it converts the actual measurement data to code. An algorithm compares the actual dimensions to the original model and identifies the differences from the nominal model. This data is fed back to the processor of the automated assembly cell.
According to aspects of the present disclosure, there is also provided a force/torque sensor attached to a robotic arm that provides feedback to a robot controller. After the robot achieves its final pre-programed position, the controller calls the “Seek Force” algorithm, which allows the robot to continue motion in a user defined vector. While moving in said vector the robot controller monitors the force/torque sensor and will continue motion until force or torque is achieved in a user defined axis and magnitude.
In a further aspect of the disclosure, the automated assembly cell adjusts the processing parameters of the component parts in order to prepare for adjustment to the actual component operations for the purpose of creating an ideal final product assembly. The process parameters for these may include cutting component parts to the proper size and angle, dip coating or spray coating parts to exact tolerances, gluing, melting or otherwise attaching two or more parts together or gluing, melting or otherwise attaching parts to fixtures, jigs, plates or holders. An additional aspect of the disclosure is automatically orienting the component parts or subassemblies to the final product assembly; using the inspection data above, the automated assembly cell can ideally locate the component parts and subassemblies in a way that will match the desired model as closely as possible.
Another aspect of the disclosure is to use a visible spectrum laser to measure the final assembly dimensions, and or interim dimensions and identify orientation or location. The automated assembly cell moves the product and/or laser to measure the dimensions, orientations and final characteristics of the final product. The digital output of the laser for dimensions can be saved electronically and combined with serialization to keep a complete digital history of the product from the component parts to the assembly as well as other downstream processes as required by several regulated industries. Another aspect can be to compare the final digital dimensions to the master model to overlay differences between the two for evaluation.
These and other embodiments, objects, features, and advantages of the present disclosure will become apparent upon reading the following detailed description of exemplary embodiments of the present disclosure, when taken in conjunction with the appended drawings, and provided claims.
The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments, objects, features, and advantages of the present disclosure.
Throughout the figures, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components or portions of the illustrated embodiments. Moreover, while the subject disclosure will now be described in detail with reference to the figures, it is done so in connection with the illustrative exemplary embodiments. It is intended that changes and modifications can be made to the described exemplary embodiments without departing from the true scope and spirit of the subject disclosure as defined by the appended claims.
Exemplary embodiment(s) of the present disclosure will be described in detail below with reference to the accompanying drawings. It is to be noted that the following exemplary embodiment(s) are merely examples for implementing the present disclosure and can be appropriately modified or changed depending on individual constructions and various conditions of apparatuses to which the present disclosure is applied. Thus, the present disclosure is in no way limited to the following exemplary embodiment(s).
The present disclosure has several embodiments and relies on patents, patent applications and other references for details known to those of the art. Therefore, when a patent, patent application, or other reference is cited or repeated herein, it should be understood that it is incorporated by reference in its entirety for all purposes as well as for the proposition that is recited.
Therefore, in one embodiment there is provided a system for automated wax mold assembly comprising an assembly cell frame; a base plate; one or more robots moveable with respect to the assembly cell frame, wherein the one or more robots comprise a robotic arm; wherein the one or more robots are in communication with a robot controller; a laser measurement and/or displacement system, end of arm tooling means for movement of mold pieces; end of arm tooling means for cutting and/or welding mold pieces; and an automation system configured to direct the placement, fitting, cutting, and/or welding of mold pieces into a completed mold.
In certain embodiments, the robots are inverted 6-axis robots. A force/torque sensor can provided on one or more of the robots, wherein the force-torque sensor is configured to detect a force or torque applied to a distal (tooling) end of the robotic arm. In certain configurations, the force-torque sensor can be in communication with a robot controller, which in turn can be in communication with a programmable logic controller (PLC).
In other embodiments, there is also provided a method for automated wax mold assembly comprising providing an assembly frame having one or more robots moveable with respect to the assembly frame, a base plate and a laser displacement system; configuring the one or more robots to select one or more mold parts from defined locations; assembling the one or more mold parts on the base plate; wherein assembling comprises one or more of placing, fitting, cutting, and/or welding of the one or more mold pieces; measuring the finished mold with the laser system; and, determining whether the finished mold meets predefined criteria. In certain embodiments, the method can also comprises measuring and/or determining the location of the one or more mold parts with the laser system. In some embodiments, the one or more robots comprise end of arm tooling means for movement of mold pieces and/or end of arm tooling means for cutting and/or welding or attaching mold pieces.
In further embodiments, wherein the method additionally comprises providing a force/torque sensor attached to at least one of the one ore more robots; configuring a robotic controller to cause the robot to perform a pre-set series of movements; wherein, when the robot reaches a pre-determined final position, causing the robotic controller to read force/torque data from the sensor, and causing the robot to continue motion toward a user provided vector if force/torque data does not meet pre-determined conditions.
Another exemplary embodiment provides a method of controlling movement of a robot, comprising providing a robot having a force/torque sensor attached thereto; configuring a robotic controller to cause the robot to perform a pre-set series of movements; wherein, when the robot reaches a pre-determined final position, causing the robotic controller to read force/torque data from the sensor, and causing the robot to continue motion toward a user provided vector if force/torque data does not meet pre-determined conditions.
Further provided is a system for controlled movement of a robot, comprising: a robot; a force/torque sensor; a robotic controller; and a programmable logic controller (PLC), wherein the force/torque sensor is attached to the robot, and sensor communicates force/torque data to the robotic controller and/or the PLC.
In other embodiments, there is provided a process for determining the accuracy of translucent wax or plastic materials, comprising using a visible spectrum length laser to measure component parts made from translucent wax or plastic materials; and comparing the measurements to a desired model of the component parts to determine any variances from the model. The visible spectrum length laser can have a wavelength of from about 400 to 700 nm. In certain embodiments, the visible spectrum length laser can obtain measurements and/or position information using any of the available techniques, including but not limited to triangulation, time of flight measurements, phase shift method, frequency modulation methods and interferometers.
In some embodiments, following the measurement of the component parts, the parts are automatically cut to size, shape and angle. In certain embodiments, the component parts are automatically machined to size, shape, angle or surface finish. In further embodiments, the component parts are automatically assembled to 2 or more other component parts to make a subassembly. The component parts, subassembly and/or completed mold (product) can be automatically precision coated with dip or spray processes. In other embodiments, the component parts and/or subassemblies are automatically glued, melted or otherwise adhered to a fixture, jig, plate or holder.
In further embodiments, there is provided an additional process step of determining the position of the component parts, comparing the detected orientation to a pre-determined desired orientation, and automatically re-orientating the component parts for alignment to attach to the final product assembly. Such processes can be performed using automated equipment, for example, an automated assembly cell according to the present disclosure.
It is also an embodiment of the present disclosure that to facilitate measurement and/or location determination of the components or products, that either the laser or product positions are automatically moved for inspection purposes. Such data provided by the laser measurement/displacement system related to the final product dimensions and orientations can be compared to the master model. In further embodiments, the data of the final product dimensions and orientations are stored digitally allowing for serialization of the final product(s).
Other embodiments provide a system comprising a visible spectrum length laser to measure component parts made from translucent wax or plastic materials to compare to a desired model for processing as described herein, wherein the system comprises automated equipment such as an automated assembly cell according to the present disclosure.
Such embodiments will now be further described with reference to the figures.
The present disclosure relates to a method and system for automating the assembly method for building a wax mold. In one exemplary embodiment, the system includes an automated assembly cell 25, wherein the automation uses multiple inverted 6-axis robots 12 to pick parts from their defined location(s) in or around an automated assembly cell 25 as shown in
After the mold assembly is complete, the laser measurement system 16 again measures the main sub-assembly, verifies the part location, and identifies the mold as being completed and conforming to the desired specifications.
By automating the wax mold assembly process, the finished product can be placed in a designated location and the process is then repeatable. Through the automation, each part on each mold is capable of achieving a more repeatable position and form, increasing the quality of the finished product. The use of the automated system additionally provides for completing the assembly of a mold faster than when the mold is prepared via a manual process.
Certain non-limiting features of the present disclosure therefore include the automated assembly of a wax mold using an assembly cell as provided in the present disclosure. Such assembly cell can include the use of inverted 6-axis robots 12 and custom software to direct the motion of the robots 12. The system and method of assembly additionally include part manipulation as a result of laser measurements to ensure fit, reduced cycle time by improved efficiency of assembly, and improved quality by reduced variation in the assembly method.
In one embodiment of the present disclosure, a force/torque sensor can be attached to one or more robotic arms within the assembly cell to provide feedback to a robot controller. After the robot achieves its final pre-programed position, the controller calls the “Seek Force” algorithm, which allows the robot to continue motion in a user defined vector. While moving in said vector the robot controller monitors the force/torque sensor and will continue motion until force or torque is achieved in a user defined axis and magnitude.
As shown in
In one exemplary embodiment, the flow chart of
Thus, according to exemplary embodiment, advantages of the present disclosure include a more robust system for handling inconsistent part geometries or final pre-programed positions for the robots 12. The present disclosure can also make teaching these positions easier in applications where the robot EOAT must come in contact or “touch” an inconsistent part, including through AI, neural nets, machine learning and the like. The user can simply teach the system the position near the object that the robot 12 must “touch” and input the vector and desired force/torque magnitude to the “Seek Force” algorithm. In this manner, the force/torque sensor 19 mounted to a robot flange 20 is able to manipulate a pre-programed robot position using feedback from said sensor 19.
According to other exemplary embodiments, the automated assembly cell 25 can utilize a visible laser system to measure and obtain position information for various components used in the molding process. Component part 1 in
In a further embodiment,
Embodiment(s) of the present disclosure, including but not limited to, programming of the desired robot movements, changing of EOAT, assembly methods, desired final product configurations, the “Seek Force” algorithm, and laser measurement and positioning determination, can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. An I/O interface can be used to provide communication interfaces to input and output devices, which may include a keyboard, a display, a mouse, a touch screen, touchless interface (e.g., a gesture recognition device) a printing device, a light pen, an optical storage device, a scanner, a microphone, a camera, a drive, communication cable and a network (either wired or wireless).
The detector interface also provides communication interfaces to input and output devices. The detector may include, for example a photomultiplier tube (PMT), a photodiode, an avalanche photodiode detector (APD), a charge-coupled device (CCD), multipixel photon counters (MPPC), or other. Also, the function of detector may be realized by computer executable instructions (e.g., one or more programs) recorded on a Storage/RAM.
In referring to the description, specific details are set forth in order to provide a thorough understanding of the examples disclosed. In other instances, well-known methods, procedures, components and circuits have not been described in detail as not to unnecessarily lengthen the present disclosure.
It should be understood that if an element or part is referred herein as being “on”, “against”, “connected to”, or “coupled to” another element or part, then it can be directly on, against, connected or coupled to the other element or part, or intervening elements or parts may be present. In contrast, if an element is referred to as being “directly on”, “directly connected to”, or “directly coupled to” another element or part, then there are no intervening elements or parts present. When used, term “and/or”, includes any and all combinations of one or more of the associated listed items, if so provided.
Spatially relative terms, such as “under” “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the various figures. It should be understood, however, that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, a relative spatial term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are to be interpreted accordingly. Similarly, the relative spatial terms “proximal” and “distal” may also be interchangeable, where applicable.
The term “about,” as used herein means, for example, within 10%, within 5%, or less. In some embodiments, the term “about” may mean within measurement error.
The terms first, second, third, etc. may be used herein to describe various elements, components, regions, parts and/or sections. It should be understood that these elements, components, regions, parts and/or sections should not be limited by these terms. These terms have been used only to distinguish one element, component, region, part, or section from another region, part, or section. Thus, a first element, component, region, part, or section discussed below could be termed a second element, component, region, part, or section without departing from the teachings herein.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “includes”, “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Specifically, these terms, when used in the present 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 not explicitly stated. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if the range 10-15 is disclosed, then 11, 12, 13, and 14 are also disclosed. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.
It will be appreciated that the methods and compositions of the instant disclosure can be incorporated in the form of a variety of embodiments, only a few of which are disclosed herein. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the disclosure to be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
The present application claims priority to U.S. Provisional Pat. Application Serial Nos. 63/046,423, 63/046,534 and 63/046,486, each of which was filed Jun. 30, 2020, and the disclosure of each of which is incorporated herein by reference in their entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/039933 | 6/30/2021 | WO |
Number | Date | Country | |
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63046423 | Jun 2020 | US | |
63046534 | Jun 2020 | US | |
63046486 | Jun 2020 | US |