The present disclosure relates to an investment casting process and a system to control investment casting mold handlers throughout a molding process.
This section provides background information related to the present disclosure which is not necessarily prior art.
Investment casting mold systems commonly include a continuous conveyor system. At one point of the conveyor un-coated wax molds are initially attached and/or completed molds are removed. As the conveyor progresses each mold has multiple operations or steps performed thereto, commonly including rinsing, dipping, sanding, and drying steps. Due to the space envelope required for a conveyor system, an individual mold is not commonly accessible after leaving the entry point until it completes at least one circuit of the conveyor. Also, when different types of molds are on the conveyor at the same time, common systems do not provide for different drying rates, therefore a complex mold may have to be retained on the conveyor for multiple passes to provide suitable drying time. An additional issue with common conveyor systems is that multiple vertical and horizontal motions may by incorporated, and damage to mold features such as sprues can result. The inability to individually remove a damaged mold at any point in the conveyor path can lead to wasted material application and lost time.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
According to several embodiments, an investment casting system includes an investment casting system including a mold transfer device operating to move a mold between at least two system sections, including a material application section having at least a first coating material to coat the mold; and a storage section receiving the mold following any one of a plurality of material coating phases in the material application section. The mold is stored in any one of a plurality of storage positions in the storage station and is selectively retrievable therefrom. The mold is accessible for removal from the system at any time and during any phase of operation on the mold.
According to further embodiments, an investment casting system includes an investment casting system includes a computer controlled mold transfer device operating to move a mold. The mold transfer device is movable between at least three stations including: a mold receiving station; a mold transfer station having a mold suspended from a first horizontally extending arm of the mold transfer device engaging an intermediate transfer device to transfer the mold to the intermediate transfer device; and a storage station having a storage rack receiving the mold following a material coating phase. A robot is in communication with the intermediate transfer device. The robot is programmed to position the mold in any of multiple material coating stations during the material coating phase. A computer control system operates to automatically identify a location of the mold and to control movement of the mold transfer device. The mold is accessible for removal from the system at any time during creation of the mold by selective operation of the computer control system.
According to still further embodiments, an investment casting system for creating a plurality of investment casting molds includes a computer controlled mold transfer device including a first horizontally extending arm operating to releasably couple any one of the molds for transfer. An intermediate transfer device includes a second horizontally extending arm, the second horizontally extending arm operating to horizontally transfer any one of the molds to and from a material application section. A storage station has a plurality of space envelopes individually adapted to temporarily store at least one of the molds following any one of a plurality of material coating phases in the material application section. Any one of the molds temporarily stored in the storage station is selectively retrievable. A computer control system operates to automatically identify a location of any one of the molds in the system and to control movement of the mold transfer device and the intermediate transfer device. Any one of the molds is accessible for removal from the system at any stage of completion by direction of the computer control system.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore 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. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” 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 figures. Spatially relative terms may be 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, the example term “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 interpreted accordingly.
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Storage/drying section 14 includes an automated mold transfer device 28 which includes a horizontal transfer arm 30 having a suspension latch member 32 connected thereto. Automated mold transfer device 28 is movable by a set of wheels 34 in either a first transfer direction “A” or an opposite second transfer direction “B”. A position sensor 38 can be provided with automated mold transfer device 28 to provide position feedback to accurately control a travel position of automated mold transfer device 28. Automated mold transfer device 28 is positioned proximate to an interior structure 40 of a first storage/drying portion 41. An exterior structure 42 provides an outer boundary structure of first storage/drying portion 41. On an opposite side of automated mold transfer device 28 a second storage/drying portion 43 is provided having a second interior structure 44 and a second exterior structure 46. First and second storage/drying portions 41, 43 provide a plurality of mold storage sites 48 which can each receive either one of the wax molds 23 or a coated mold 49. Coated molds 49 are created when wax molds 23 are passed through material application section 18. Each of the wax molds 23 or coated molds 49 are supported in a suspended orientation in each of the mold storage sites 48.
An off-load transition station 50 is provided in either one of first or second storage/drying portions 41, 43 which is positioned proximate to material application section 18. In the exemplary embodiment of
Material application section 18 includes a robot 60 having a robot arm 62 radially extendable through an arc of rotation 64. Arc of rotation 64 permits the robot 60 to move either the wax mold 23 or the coated mold 49 between each of a pre-wetting tank 66, an etch tank 68, a rinse tank 70, and a ceramic slurry tank 72 where the suspended orientation of the molds permits them to be dipped downwardly into and vertically upwardly withdrawn from any of the tanks minimizing angular motion of the molds.
Material application section 18 further includes first and second grain size sand coating drums 74, 76. After the molds are dipped into any or all of the tanks 66, 68, 70, or 72, each mold can be inserted using robot 60 and robot arm 62 into one of the first or second grain size sand coating drums 74, 76 where a coating of sand is applied over the mold. Different grain size sands are provided for each of the first and second grain size coating drums 74, 76 for different types or sizes of the molds and different coating thicknesses.
A mold is initially introduced into material application section 18 by transfer from off-load transition station 50 to mold pick-up station 52 where robot arm 62 engages the mold and removes it from mold pick-up station 52. When a predefined sequence of operations are performed on the mold in material application section 18, the mold is returned to storage/drying section 14 by offloading the mold to the on-load transition station 56 where it is subsequently horizontally moved to the mold drop-off station 54. When the mold is received in mold drop-off station 54 it is accessible by automated mold transfer device 28 to be retrieved or deposited at one of the plurality of mold storage sites 48 or delivered to the discharge section 20 if mold formation is complete. Each mold as either the wax mold 23 or the coated mold 49 can be temporarily stored in one of the mold storage sites 48 for an indefinite period of time to allow for drying of the mold or for subsequent pick up by automated mold transfer device 28 for a first, second or later transfer to the material application section 18.
When an individual coated mold 49 is complete, it is transferred by automated mold transfer device 28 to a discharge receiving station 78. From discharge receiving station 78 the finished mold is manually translated to an off-load station 80 by an operator/programmer 82 for subsequent performance of a casting operation. A control unit or computer control system 84 is provided with mold handling system 10 allowing operator/programmer 82 to enter individual commands into computer control system 84 defining how each individual mold is handled by mold handling system 10. Multiple different molds having different mold geometries can therefore be accommodated by mold handling system 10 through the use of individual programs entered or stored in computer control system 84. It is also possible through the use of computer control system 84 for the operator/programmer 82 to direct automated mold transfer device 28 to remove any individual mold from mold handling system 10 at any time or at any point of operation for any reason, for example if it is discovered that the individual mold has been damaged, which can occur by disconnection of a mold sprue. Additional cycles through material application section 18 can also be added by operator/programmer 82 if warranted.
It is therefore possible for any individual mold in mold handing system 10 to be accessed at any operating stage or location of the system. Under normal operating conditions computer control system 84 will notify operator/programmer 82 when any individual one of the molds has completed its predetermined number of cycles through material application section 18 and storage/drying section 14. Under normal operating conditions of mold handling system 10 individual molds are completely autonomously handled by automated mold transfer device 28 via commands or one or more programs entered into computer control system 84 or modified by the operator/programmer.
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Transfer section 16 includes a first horizontal transfer device 108 operating to horizontally translate the wax mold 23 from entry station 24 to receiving station 26. A second horizontal transfer device 110 operates to horizontally translate wax mold 23′ from off-load transition station 50 to mold pick-up station 52.
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According to several embodiments, each of the mold storage sites 48 can be provided with a common storage level height “C”, however, individual mold storage sites such as a mold storage site 118 can have dimensionally different limitations compared to a mold storage site 120 at the discretion of the designer. This further provides for the storage of molds of different sizes or geometries in storage/drying section 14′. It is noted that each of the individual mold storage sites such as mold storage sites 118, 120 has a unique identifier 121 stored in computer control system 84 such that mold handling system 10 is able to individually recognize a location and the envelope size of each one of the storage sites.
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During drying in storage/drying section 14, coated molds 49 can be positioned in two or more sections of storage/drying section 14, shown for example as mold storage sites 48 and mold storage sites 154. Where drying air provided via first humidity controlled ventilation section 98 can be delivered to mold storage sites 48, a higher or lower volumetric flow rate of the humidity controlled air can be delivered to mold storage sites 154 via a volume delivery controlled portion 156 of first humidity controlled ventilation section 98. This permits drying rates to be further controlled by delivery of a higher or lower volume of drying air (for example at a higher or lower velocity of flow, or higher or lower total volumetric flow rate) to coated molds 49 which are temporarily stored in mold storage sites 154 compared to mold storage sites 48.
When the coated mold has received the predetermined number of layers of coating and has dried sufficiently to be off-loaded from mold handling system 10, automated mold transfer device 28 is commanded to retrieve the finished, coated mold (for example designated as mold 49a) from the appropriate mold storage site 48 or 154 for transfer to the discharge receiving station 78. The operator/programmer 82 at discharge receiving station 78 can manually transfer the coated mold 49 to off-load station 80 where the coated mold 49 can then be moved to either a temporary storage location or directly into a casting facility (not shown) where a casting material can be poured into the mold. The computer control system 84 as previously discussed controls each of the movement steps of the wax mold 23 or coated mold 49 throughout its flow path through mold handling system 10.
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Horizontal transfer device 166 can subsequently couple hanger plate 158 to a rack connector/hanger 170 provided in individual ones of the mold storage sites 48 of storage/drying section 14 to store the molds 49. It is therefore possible to temporarily store one or more than one mold 49 in each of the storage sites 48 when supported from hanger plate 158. Each of the molds 49 supported by hanger plate 158 fit within a space envelope 171 which is predetermined to fit within any of the storage sites 48. First and second structural plates 172, 174 slidably support compensator shaft 168.
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Several advantages of the use of mold handling system 10 are provided by the elimination of a standard conveyor system which precludes access to the mold at any particular step and requires the mold to be moved in a complete cycle about the conveyor before it is accessible again. The combination of the use of robot 60, transfer section 16, and storage/drying section 14 allows any one of the molds at any point in mold handling system 10 to be accessed for either removal or for further coating steps. In addition, storage/drying section 14 can be designed to provide different sections or areas where controlled humidity ventilation can be varied so that a mold positioned in different areas of the storage/drying section 14 can be provided by different humidified drying air to further control the rate of drying to either lengthen or reduce the drying period for the mold. This permits larger or smaller molds which have different drying times based on the surface area to be coated or the complexity of the surface area to be coated to be handled differently within mold handling system 10 without removal of the mold prematurely or requiring an excessive stay time within the system before it can be removed.
The storage/drying section 14 as noted herein can include at least first and second humidity controlled ventilation sections 98, 100. The mold 49 is positioned in one of the plurality of space envelopes 171 of one of the first or second humidity controlled ventilation sections 98, 100 each providing a selectively different drying rate for the mold. A total drying time of the mold 49 is predetermined and stored in the computer control system 84 and is continuously compared using the computer control system 84 to the accumulated drying time of the mold 49 at the drying rate provided in the individual first or second humidity controlled ventilation sections 98, 100.
Further, the capability to horizontally transfer and translate any of the molds for any of the operations related to the storage/drying section 14 and or transfer section 16 minimize the period when the mold may not be positioned in its vertical suspended state and therefore minimize the stresses seen by the mold as it moves from one station to another. This mitigates against the potential for angularly twisting the mold unnecessarily which can damage various components of the mold such as the sprue or sprues. The molds transferred by the mold handling system 10 are continuously vertically suspended at all steps of the operation with the acception of the mold movements within either of the first or second grain size sand coating drums 74, 76 or in one of the dryer units 152. Further, by manual entry of data into computer control system 84, an operator can direct access to any individual one of the molds at any stage in mold handling system 10 for example to remove a mold if the mold is damaged. The operator can also input commands to computer control system 84 that indicate the type of mold being entered into mold handling system 10 such that a preprogrammed set of operational steps which are predetermined to optimize the coating and minimize the stay time within mold handling system 10 based on the geometry and type of mold can be used.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.