The invention relates to the field of tooling and systems for metalworking operations.
The development of metalworking machines was one of the key factors in the Industrial Revolution that began around the turn of the nineteenth century. This was a class of machine that could make almost anything, including reproducing itself. Researchers in manufacturing processes soon realized that more efficient metalworking machines would reduce the manufacturing cost of whatever products were being made. Thus, great effort was devoted toward understand the various metalworking processes, to increase metal cutting rates, and the like. Better cutting tools were developed. More powerful metalworking machines were developed. Manufacturing engineers came to realize that the most efficient metal cutting operations were those in which the cutting tools were worn out in a surprisingly short time; cutting tools became expendable items in the costs of a manufacturing operation.
As a result of the considerable research devoted to metal cutting operations, the time required for such operations was steadily reduced. While further efforts in this direction will undoubtedly reduce manufacturing time, one can ponder whether the point of diminishing returns has been reached. Researchers in manufacturing engineering began to address this matter many years ago. One researcher found that metal cutting accounted for less than 20% of the time that a part spent in a manufacturing plant. Most of the remaining time was spent awaiting the next manufacturing operation. This realization led to development of dedicated tooling that would be used for the manufacture of just one type of part, but with a reduced time for changing workpieces. It also led to more sophisticated plant layouts, so that the parts flowed through a factory in a logical fashion. Cellular manufacturing was developed. Under this concept, several different manufacturing machines, together with necessary accessory equipment, were clustered in one area of a factory. Thus, a batch of parts could go from incoming raw material to virtually complete parts with few, if any, excursions to other locations where manufacturing operations were performed. Time required for shipping a batch of parts around the plant was significantly reduced. Time spent trying to find parts that had been lost during intra-factory shipment was also reduced.
Managers of manufacturing enterprises began to keep track of work in progress, and to recognize the substantial investment that work in progress represents. Such efforts led to decreasing the number of components kept in inventory for subsequent manufacturing or assembly operations, and to decreasing the inventories of finished products awaiting shipment. The favored size for batches of parts became smaller. While such trends represent reduction in overall costs of manufacturing, such trends also placed pressure on manufacturing operations to change tooling between different manufacturing processes more quickly. The combination of smaller batch size and more widespread use of manufacturing cells has accentuated the need for reducing the time required for changeover of tooling.
Metalworking frequently involves precision machining of workpieces, often within tolerances of a few mils. (One mil is 0.001 inch, or 25 micrometers.) One of the essential prerequisites of precision machining is rigid support of the workpiece. In conventional metalworking practice, dedicated tooling to hold a particular workpiece for the metalworking operation is provided. Such dedicated tooling must provide rigid support for the workpiece.
A metalworking operation can involve the machining of families of workpieces of the same general, proportional shape, but different in size and dimensions. Typically, a family of dedicated holding devices is required for a family of workpiece members. While some parts in a workpiece family can be very small, and the associated dedicated tooling can be manipulated and carried by hand, other workpieces and their dedicated tooling can be much larger, requiring mechanical assistance (e.g., a crane) to lift, carry and position the dedicated tooling devices.
Dedicated tooling is designed to hold one workpiece family member in a precise location and position for the metalworking operation. The alignment of the dedicated tooling and the workpiece it holds to the metalworking machine must be exact, and often requires significant setup time to ensure proper alignment with the metalworking machine. Achieving such alignment is a trial-and-error process, generally requiring repeated steps of tapping the tooling to move it a small distance, tightening the bolts used to secure it in place, and then checking the alignment using dial indicators or the like. The critical nature of this process typically requires attention by the most highly skilled workers in the manufacturing facility. Often, trial parts of the workpiece must be test worked, with minute adjustments of the dedicated tooling to the worktable, to ensure the metalworking operation machines the workpiece properly.
When a metalworking facility needs to machine a variety of members of a workpiece family, there can be significant amounts of production time lost in tooling changeover, in disassembling tooling used on the first workpiece, retrieving the dedicated tooling for the next workpiece, and then installing and aligning the retrieved dedicated tooling, etc. Changing the tooling from that required for one workpiece to that required for another similar workpiece is frequently a major factor in the cost for operating a metalworking facility, particularly when business conditions in the industry can necessitate small production lot sizes.
In addition, to machine a family of workpieces that are similar in size but different in detail, equivalent families of dedicated tooling must be manufactured. Because each set of dedicated tooling must accept and secure the workpiece in generally two or more places for proper positioning and alignment, these dedicated tools can be complex and expensive.
Considerable savings in manufacturing costs can be achieved by simplifying the tooling changeover process.
The issues discussed hereinabove are well known to those skilled in the metalworking arts and in manufacturing engineering, and are described in Manufacturing Engineering and Technology (Fourth Edition), by Serope Kalpakjian and Steven R. Schmid.
An embodiment of the invention provides a modular tooling apparatus for performing a metalworking operation on a workpiece, comprising: a base comprising an attachment surface, the attachment surface comprising a locating feature; and an insert associated with the attachment surface, the insert comprising a locating feature, and a workpiece support feature on a surface thereof; wherein the locating feature on the insert is configured to associate with the locating feature of the attachment surface to define a location of the workpiece support feature relative to the base.
Another embodiment of the invention provides a modular tooling apparatus for performing a metalworking operation on a workpiece, comprising: a base comprising at least a first attachment surface and a second attachment surface, each attachment surface comprising a locating feature; and at least a first set of inserts comprising at least first and second inserts, corresponding to and associating with the first and second attachment surfaces, respectively, each of the inserts comprising a locating feature and a workpiece support feature on a surface thereof; wherein each insert locating feature is configured to associate with the corresponding locating feature of the attachment surface to define a location of each workpiece support feature relative to the base.
Another embodiment of the invention provides a method for performing a metalworking operation on a workpiece using a modular tooling apparatus, comprising the steps of: a) providing a modular tooling apparatus comprising a common base, the common base comprising at least one attachment surface comprising a locating feature, and a first insert comprising a locating feature, and a workpiece support feature on a surface thereof, b) positioning the common base to a table of a metalworking machine; c) associating and securing the first insert to the attachment surface, wherein the locating feature on the first insert is configured to associate with the locating feature of the attachment surface to define a location of the workpiece support feature of the first insert relative to the common base; d) aligning the common base with the metalworking machine; e) securing semi-permanently the aligned common base to the table; f) providing a first workpiece; g) positioning and securing the first workpiece onto the workpiece support feature of the first insert, wherein the first workpiece assumes a characteristic position and orientation relative to the metalworking machine for machining of the workpiece; h) machining the first workpiece; and i) removing the machined first workpiece from the first insert.
A further embodiment of the invention provides a method for performing a metalworking operation on a family of workpieces using a modular tooling apparatus, comprising the steps of: a) providing a modular tooling apparatus comprising a common base, the common base comprising at least one attachment surface comprising a locating feature, and a first insert comprising a first member of a first family of insert members that are related but different in detail, the first insert comprising a locating feature and a workpiece support feature on a surface thereof; b) positioning the common base to a table of a metalworking machine; c) associating and securing the first insert to the attachment surface, wherein the locating feature on the first insert is configured to associate with the locating feature of the attachment surface to define a location of the workpiece support feature of the first insert relative to the common base; d) aligning the common base with the metalworking machine; e) securing semi-permanently the aligned common base to the table; f) providing a first workpiece selected from a family of workpiece members that are related but different in detail; g) positioning and securing the first workpiece onto the workpiece support feature of the first insert, wherein the first workpiece assumes a characteristic position and orientation relative to the metalworking machine for machining of the workpiece; h) machining the first workpiece; i) removing the machined first workpiece from the first insert; j) removing the first insert from the attachment surface of the common base; k) providing a second insert comprising a second member of the first family of insert members, the second insert comprising a locating feature and a workpiece support feature on a surface thereof, and providing a second workpiece selected from the family of workpiece members; l) associating and securing the second insert to the attachment surface, wherein the locating feature on the second insert is configured to associate with the locating feature of the attachment surface to define a location of the workpiece support feature of the second insert relative to the common base; m) positioning and securing the second workpiece onto the workpiece support feature of the second insert, wherein the second workpiece assumes a characteristic position and orientation relative to the metalworking machinel for machining of the second workpiece; n) machining the second workpiece with the metalworking machine; and o) removing the machined second workpiece from the second insert.
Definitions:
As used herein, the phrase “metalworking machine” refers to any machine for the cutting, forming, joining or otherwise processing of a metallic workpiece. The term can include, but is not limited to, a milling machine, a planer, a shaper, a drill press, a vertical turret lathe, a grinder, EDM and ECM machines, a broaching machine, a bending brake, a stamping press, and a welding apparatus. In a broad context, the term can also include such diverse forms of equipment as a lathe or a die casting machine.
As used herein, the term “tooling” refers to an apparatus for holding and supporting a workpiece while it is being cut, formed, joined or otherwise processed by a metalworking machine.
As used herein, the term “tool” refers to an apparatus used by a metalworking machine to cut, form, join or otherwise process a workpiece.
As used herein, a “set” of inserts is a plurality of inserts configured to cooperatively support a single workpiece in a modular tooling apparatus. Generally, there is a set of pockets on a base that corresponds with the set of inserts.
As used herein, a “family” is a plurality of related members. A “family” of workpieces is a plurality of workpieces that has substantially the same shape and features, though the workpieces are different in size or proportion, and are thus related but different in detail. A “family” of inserts is a plurality of inserts, or of sets of inserts, configured to hold or support members of a corresponding family of workpieces at the same position on the workpiece, and are thus related but different in detail.
As used herein, “corresponding” or similar word form refers to insert A associating with and fitting into pocket A, insert B into pocket B, etc. The term can also refer to insert A associating and supporting workpiece A, insert B associating and supporting workpiece B, etc.
As used herein, a “locating feature” is a surface or a combination of surfaces on an element configured to ensure positive positioning and/or orientation at a location with respect to the base, and with respect to the metalworking operation, with a high degree of accuracy and repeatability.
As used herein, a “location” of a workpiece support feature is a precise position (in x, y and z space) and orientation (relative to x, y, and z axes) relative to the base. A “location” of a workpiece that is being held in position by one or more workpiece support features is its corresponding precise position (in x, y and z space) and orientation (relative to x, y, and z axes) relative to the metalworking operation.
As used herein, the term “chips” includes all forms of debris generated in a metalworking operation, including, but not limited to, chips, grinding swarf, metal particles formed in EDM, ECM and laser cutting operations, weld spatter and flux particles, and the like.
The present invention provides an improvement in metalworking tooling used to support metal workpieces in a metalworking operation. The improved metalworking tooling comprises a modular tooling apparatus for performing a metalworking operation on a workpiece or a family of workpieces. The modular tooling apparatus consists of a base having one or more attachment surfaces, and one or more inserts that can be attached semi-permanently to the attachment surface. The attachment surface is typically a pocket in the surface of the base. The insert has a workpiece support feature that can support or secure the workpiece into the proper position and orientation for machining. The base, pockets and inserts are configured to provide a characteristic location and orientation for the workpiece relative to the base, and to the metalworking machine. The modular tooling apparatus permits machining a family of workpiece members that are related in shape but different in detail, by inserting an insert member from the family of inserts to properly position and orient the corresponding workpiece member, without needing to change, disconnect, or move the base tooling.
The base of the invention comprises an attachment surface to which an insert can associate. Typically, the insert associates with the attachment surface by a mechanical engagement that at least partially and temporarily secures the insert to the base.
An embodiment of the invention is shown in
The base 20 can be constructed to comprise a plurality of members that are joined together semi-permanently. The members are typically comprised of non-movable members and moveable members. Non-movable members can comprise a series of distinct laminar plates, aligned and fastened together, as by bolting. The moveable member can comprise one or more of a variety of plates, hardware and devices that assist in the loading and support of the workpiece, and the discharging of the machined workpiece from the modular tooling apparatus. An example of a moveable member includes, but is not limited to, a force means such as a hydraulic or pneumatic clamp, a manual toggle clamps, a fixed workpiece support member, and a pneumatic or hydraulic ejector. A pocket located on the base can be associated with a movable member or plate of the base, or with a non-moveable member of the base, as herein after described.
The attachment surface of the base typically comprises a pocket. A pocket can be a depression in the surface of the base that is configured to receive an associating element of an insert. The pocket 30 shown in
The pocket 30 has a locating feature that comprises a plurality of locating members defined by the floor 33, the sidewall 34, and the backwall 35. These three planar locating features cooperate to identify a characteristic locating point 31.
The insert 50 has an upper portion and a lower portion 56. The lower portion 56 of the insert has a front wall 57, a backwall 55, a rear toe 59 having rear sidewall 54, a front toe 58 having a front sidewall, and a bottom 53. These features are particularly configured and oriented to associate with corresponding features of the pocket 30.
Insert 50 associates with the pocket 30 by sliding lower portion 56 through the opening 36 of pocket 30. The insert is configured to be separated from the pocket by hand, without the use of a mechanic's tool, such as a wrench or screwdriver. The insert 50 has a locating feature which comprises a plurality of locating members defined by the bottom 53, sidewall 54, and backwall 55 of the lower portion 56. Theses three planar locating features cooperate to identify a characteristic insert locating point 51. The insert can have a plurality of locating points, defined by the cooperation of one or more locating features, which can include surfaces, edges and points on the surface of the insert.
The upper portion of insert 50 has a workpiece support feature upon a surface thereof. The workpiece support feature comprises a plurality of workpiece support members defined by the confronting inclined planes 71 and 72, and the ball joint restraints 73 shown in
The extent to which the insert 50 is restrained against movement relative to the base 20 is limited by three factors: (1) the precision employed in manufacturing the associated parts, (2) the ability to place the insert in and remove it from the pocket, and (3) the ability to restrain the insert against movement in the +x direction.
The lower portion 56 is configured to fit precisely into pocket 30 whereby the locating feature of the insert and the corresponding locating feature of the pocket cooperate to define a location of the workpiece support feature relative to the base 20. The functionality of the insert and pocket arrangement is that the insert slides into the pocket to establish a precise spatial relationship therewith. Thus, the relationship between corresponding features when the insert is seated in the pocket is confronting. However, during removal and insertion of the insert relative to the pocket, the relationship between corresponding features is sliding. The sliding relationship is particularly apparent with respect to the pocket sidewalls and toe sidewall of the insert, to the clearance recess below the ledges of the pocket and the toes of the insert, and to the floor of the pocket and the bottom of the insert. The lower portion 56 of the insert 50 must be carefully constructed such that the dimensions thereof allow for a sliding relationship with the pocket 30, but with minimum movement of the insert within the pocket. For inserts having characteristic dimensions on the order of a few inches (several centimeters), the space between corresponding features is typically about one mil (one mil equals 0.001 inch, or 25 microns). The clearance between corresponding vertical surfaces is typically less than about 0.001 inch per side, per inch (1 micron per side, per millimeter) of linear dimension of that surface. In the design and construction of the insert and pocket, one can compromise between free movement and rigid positioning of the insert, thereby reasonably meeting both requirements. Dimensional tolerances appropriate to such clearances can be achieved by various grinding operations, or by reaming a hole, or by cutting a contoured surface by electrical discharge machining (EDM), using a moving wire as the cutting electrode (wire EDM).
Dimensional tolerances of the pocket 30 can be more difficult to achieve than the dimensional tolerances of the inserts. Further, accurately machining the interior corners between the front or back surfaces and adjacent side surfaces is particularly difficult. A typical solution involves the use of ground plates for the side surfaces of the pocket, and of one or more ground spacer blocks for the front, back and bottom surfaces of the pocket. In a simple form, the base is assembled from three plates that are pinned and bolted together, and separated only for maintenance of the modular tooling apparatus. A typical material for both the base and an insert is hardened tool steel, which resists many assembly methods, especially welding. The insert is then ground to fit the pocket, allowing for the clearance dimensions set forth hereinabove.
The locating planes 33, 34, and 35 of the pocket 30 are in confronting contact with the corresponding locating planes 53, 54, and 55 of the inserted lower portion 56. Provided that these features are designed and machined precisely, the locating points 31 of the pocket and 51 of the insert become substantially co-located. Co-locating the locating points thereby defines the characteristic location of the workpiece support feature relative to the reference point of the base 20.
In the embodiment of the invention shown in
The insert 50 also comprises a pocket orientation feature so that the insert 50 can be associated with pocket 30 in only one orientation. The pocket orientation feature comprises rear toe 59 having a height higher than that of front toe 58. As shown in
The insert 50 also comprises a workpiece orientation feature so that a workpiece 98 can have only one orientation when associated with the workpiece support feature of the properly-inserted insert 50. In
The location of the cooperating workpiece support feature of insert 50 (workpiece support members 71, 72, and 73) defines a location of the workpiece 98 in reference to the base 20. The location of the workpiece provides a characteristic position of a reference point of the workpiece in x, y and z space, and a characteristic orientation of the workpiece (its pitch, roll, and yaw) about its x, y and z axes.
Under the forces applied by milling machines of a metalworking operation, the workpiece is prone to movement, shifting and vibration. To prevent movement of the workpiece during the metalworking operation, the workpiece is typically secured to avoid movement and/or vibration during machining. Typically, an insert is secured in a pocket whereby only one direction is unsecured by the pocket itself (that is, the position by which the insert was inserted into the pocket). Pocket and insert configurations are selected to avoid the action of forces from the metalworking operation upon the insert in that one direction. Typically, an insert and pocket will not be configured whereby the force from the metalworking operation applies a force upon the insert in the direction of the insert's insertion or removal. An insert is more typically configured whereby, when a metalworking operation exerts force upon the workpiece 98, the workpiece will exert a resulting force upon the insert that contributes to securing the insert into the pocket. That is, the force of the metalworking operation on the workpiece assists in securing the insert to the base. A secondary consideration in designing the modular tooling apparatus is minimizing the extent of forces related to clamping a workpiece that act in the one direction associated with placing the insert in its corresponding pocket.
The forces exerted upon a workpiece by a metalworking machine can require one or more force means to secure the workpiece. Any shifting, moving, flexing, or vibration of the workpiece during a metalworking operation can result in improper machining of the workpiece. An insert of the present invention can be used to position the workpiece in the proper position for the metalworking operation, and can also be used to secure the workpiece by resisting movement by virtue of its rigid attachment to the base and table, or by exerting a force upon the workpiece. The modular tooling apparatus of the invention can employ one or more means of exerting a restraining force upon the workpiece. The restraining force means is particularly important when the workpiece is flexible or bendable. Typically, the restraining force is exerted on the workpiece as close to the path of the metalworking machine as is practical, to maintain the rigidity of the workpiece during the metalworking operation.
Typically the securing force that is applied to the workpiece exerts, through the workpiece, a force upon an insert that is securing or supporting the workpiece. A securing force is typically configured whereby the force upon the insert is in a direction that contributes to securing the insert into the pocket.
A first force means can be configured to apply a force upon the head 603 of the workpiece 98 to secure the workpiece against the ball joint restraints 73. The direction of force of the first force means is shown in
A second force means can be configured to apply a force upon the upper surface of the body 601 along edge 613 to secure the workpiece against the workpiece support members 71 and 72. The direction of the second force means is shown in
Typically, the clamp 710 can comprise another insert 650, shown in
Insert 650 associates with the pocket 630 by sliding pin 656 through the opening 636 of pocket 630. The pin 656 comprises an elongated shaft having a shape configured to associate with the sidewalls of the pocket 630, to provide slidable confronting contact between the pin and the shaft having the precise spatial relationships described for the embodiment of the pocket 30 and insert 50 herein above. The insert 650 has a locating feature that comprises a plurality of locating members defined by the sides 653 and 654 of the pin 656, and by the engaging surface 655 of the hook 658. These three locating features cooperate to identify a characteristic locating point 651 of the insert 650. As with insert 50, the moveable insert 650 can have a plurality of locating points 651, defined by the cooperation of one or more locating features, which can include surfaces, edges and points on the surface of the insert.
The insert 650 has a securement comprising rocker 659 having hook 658 which aligns with and engages catch 637 of the pocket when the pin 656 is fully inserted into the passage of the pocket 630. The rocker has a biasing means, such as a spring (not shown) to bias the hook end in the secured position with the catch 637. The insert 650 can be disengaged and removed from the pocket by depressing trigger 690 of the rocker 659, which pulls away and disengages the hook 658 from the catch 637. The insert is configured to be separated from the pocket by hand without the use of a mechanic's tool.
The inset 650 has a workpiece support feature upon a surface thereof. The workpiece support feature comprises a plurality of workpiece support members defined by the planar surface 671 and 672. These support surfaces support corresponding surfaces on the workpiece 98 as shown in
With the pin 656 inserted into the pocket 630, as shown in
The insert 650 can optionally have a pocket orientation feature. A pocket orientation feature shown in
The installed and secured workpiece is ready for machining. The workpiece support feature of insert 50 positions the workpiece 98 into the proper location and orientation for the metalworking operation (the bore cutting and milling). The workpiece is secured into the proper location and orientation with securing force A and securing force B.
After machining the workpiece 98, the machined piece is released from the inserts and supports (such as any force means related to force A and B, including any moveable inserts), and removed from the apparatus. The machined workpiece can be removed by hand, but is typically removed by an automated means known in the art, such as a pneumatic ejector. For automated ejection of the workpiece, it is typical to configure the insert and workpiece support features for loading of the workpiece from a side of the apparatus, so that the machine workpiece can be ejected out and away from the apparatus. After ejection of a machined workpiece, a successive identical workpiece 98 can be loaded into the device and secured for machining, whereby the workpiece support feature of the fixed insert remains semi-permanently fixed in position in between the metalworking operations upon the successive workpieces 98. The successive workpiece 98 is in the proper position and orientation for machining of the bore 605 and flat surface 607.
An embodiment of the invention can also provide a base having a fixed workpiece support member affixed permanently to the base. A workpiece can require support both from the insert, and at another surface. A fixed workpiece support member can be configured to cooperate with the workpiece support feature of the insert 50 to position and orientate such workpiece. The fixed workpiece support member would not be removable.
In a typical method of performing a metalworking operation on a workpiece, a common base is provided and positioned onto the table. The base has at least one attachment surface that is typical configured as a pocket as described herein above. A first insert is associated and secured to the attachment surface. The insert is typically configured to associate with the attachment surface as described herein above to define a location of its workpiece support feature relative to the common base. After aligning the common base with the metalworking machine, the common base is secured to the table by a semi-permanent securement that allows the base to be unsecured, re-aligned, re-secured, and removed from the table. A provided first workpiece is positioned and secured onto the workpiece support feature of the insert, as described herein above, wherein the workpiece assumes a characteristic position and orientation relative to the metalworking machine. The characteristic position of the workpiece is such that the machining of the workpiece is completed acceptably. The machining of the workpiece removes or modifies the material of the workpiece so that the machined workpiece has the properties and configuration intended from the metalworking operation. After machining of the workpiece any restraining forces or securements are removed, to release the workpiece for removal from the workpiece support feature of the first insert.
A metalworking operation using a modular tooling apparatus that has a single insert can be performed on a successive workpiece member of a family of workpieces that are related in configuration but different in detail. A family of inserts can be configured whereby each insert member is configured to associate semi-permanently with a common attachment surface (here, a pocket). The successive members of the family of inserts have workpiece support features that are configured to position and orient their respective workpiece members in a location and orientation that permits machining of the workpiece without changing the tooling base, or making any adjustment in the position or orientation of the base 20 upon the metalworking machine. An entire family of workpieces can be machined on a modular tooling apparatus using a common base and a corresponding family of inserts.
After the last of machined first workpieces has been removed from the workpiece support feature, the first insert is removed from the base. A provided second insert, comprising a second member of the family of inserts, is associated and secured to the attachment surface of the base, wherein its locating feature is configured to associate with the locating feature of the attachment surface to define a location of the workpiece support feature of the second insert relative to the base. A second member of the family of workpieces is then positioned onto and secured to the workpiece support feature of the second insert. The second workpiece assumes a characteristic position and orientation relative to the metalworking machine for machining of the workpiece. After machining the second workpiece, the machined workpiece is removed from the workpiece support feature of the second insert.
The replacement of the first insert with the second inserts enables machining a second workpiece after the machining of a first workpiece without requiring a intermediate step of aligning the common base with the metalworking machine.
Another embodiment of the invention is shown in
Pocket 30 and insert 50 are as described hereinabove.
The pocket 40 is defined by front wall 47, back wall 45, sidewalls 44, and floor 43. The sidewalls 44 are typically parallel to each other, as are the front wall 47 and the back wall 45. Each of these walls is typically perpendicular to the floor 43. The back wall 45 is provided with an overhanging lip 46, with a clearance recess 48 there below.
The insert 60 is provided with features that correspond to the features of the pocket 40. The lower portion 66 of the insert 60 is defined by a front surface 67, a back surface 65, side surfaces 64, and a bottom surface 63. These features are particularly configured and oriented to associate with corresponding features of the pocket 40. Correspondence between features of the pocket 40 and insert 60 is indicated by a common third digit of the respective identification numbers; for example, the back wall 45 of the pocket corresponds to the back surface 65 of the insert. In addition, the lower portion is provided with a top surface 62, a toe 68 having an upper restraining surface 66 thereon, and relief curvatures 69.
The functionality of the insert and pocket arrangement is that the insert slide into the pocket and establish a precise spatial relationship therewith. Thus, the relationship between corresponding features when the insert is seated in the pocket is confronting. However, during removal/insertion of the insert relative to the pocket, the relationship between corresponding features is sliding. The sliding relationship is particularly apparent with respect to front wall 47 and front surface 67, to sidewalls 44 and side surfaces 64, and to underside of overhanging lip 46 and the upper restraining surface 66. There is some sliding between the floor 43 and the bottom surface 63 as the toe 68 is engaged with the clearance recess 48.
Some means of restraining the insert against movement in the +z direction (upward) is deemed appropriate, particularly at the front side of the insert. To accomplish this restraining action, an extraction/locking device 370 is provided. The extraction/locking device 370 is pivotably disposed in a slot 328 in the base 20. The width of the slot is exaggerated in
A detent means, to retain the extraction/locking device in its first position, is provided. In a typical embodiment of the detent means, a retaining pin 375 is slidably disposed in a hole through a front aspect of the base 20, and biased against the extraction/locking device, such that it snaps into a locating hole 376 in the extraction/locking device when the extraction/locking device is moved to its first position. The detent means urges the extraction/locking device to remain in its first position. A knob or knurled surface on the exposed end of the retaining pin facilitates convenient disengagement thereof from the hole in the extraction/locking device.
The extraction/locking device provides an additional function, namely, to facilitate extraction of the insert 60 from the pocket 40. Typically, an extraction/locking device can be used when an insert 60 does not have a convenient handle for a technician to grasp to extract the insert from its pocket. The extraction/locking device typically comprises an extraction feature that is configured to press against a surface of the lower portion 66 of the insert 60, as the extraction/locking device is pivoted to its second position. As the extraction/locking device 370 is rotated toward its second, or extraction, position, a toe 374 exerts an upward force on the bottom 63 of the insert 60, thereby exposing the front and back surfaces of the insert sufficiently for a technician to grab the insert. The second position of the extraction/locking device is shown in
Pocket 40 has a corresponding locating feature that comprises a plurality of locating members defined by the floor 43, the rear sidewall 44, and the backwall 45. These three planar locating features cooperate to identify a characteristic locating point 41 of the pocket 40.
The corresponding insert 60 has a locating feature, which comprises a plurality of locating members defined by the bottom 63, rear sidewall 64, and backwall 65. Theses three planar locating features cooperate to identify a characteristic locating point 61 of the insert 60.
The insert 60 has a workpiece support feature upon a surface thereof. When insert 60 is inserted into pocket 40, the locating points 41 of the pocket and 61 of the insert become co-located. Co-locating the locating points thereby defines the characteristic location of the workpiece support feature of the insert relative to the reference point of the base 20. The workpiece support feature comprises a plurality of workpiece support members defined by the confronting inclined planes 76 and 77. These support surfaces support corresponding surfaces on the workpiece as shown in
The insert 60 also comprises a pocket orientation feature, to associate the insert with the pocket 40 in only one orientation. The pocket orientation feature comprises toe 68 of the insert and its association with clearance recess 48 of the pocket. If the insert is turned 180° about its z axis (not shown), it can not be inserted into the pocket. This feature prevents a user of the apparatus from inserting the insert 60 improperly.
The insert 60 also comprises a workpiece orientation feature so that a workpiece 198 can have only one orientation when associated with the workpiece support feature of the properly-inserted insert 60. The workpiece orientation feature comprises a shoulder 106 that extends upwardly from the support surface comprising workpiece support member 77. The shoulder 106 is configured to register with the flat 811 of the workpiece 198 (shown in
Workpiece 198 (prior to metalworking) has several features identical configuration and dimensions to the workpiece 98 of
In another typical method of performing a metalworking operation on a workpiece, the base uses at least two inserts associated with corresponding first and second attachment surfaces. The first insert is a first member of a first family of inserts, and associates with the first attachment surface. The second insert is a first member of a second family of inserts, and associates with the second attachment surface. A provided first workpiece is positioned and secured onto the workpiece support features of the two inserts, as described herein above, wherein the workpiece assumes a characteristic position and orientation relative to the metalworking machine. The characteristic position of the workpiece is such that the machining of the workpiece is completed acceptably. The machining of the workpiece removes or modifies the material of the workpiece so that the machined workpiece has the properties and configuration intended from the metalworking operation. After machining of the workpiece, any restraining forces are removed to release the workpiece for removal from the workpiece support features of the first and second inserts.
The metalworking operation also optionally includes a step of evaluating the machined workpiece, to ensure the machining operation has been performed acceptably. An evaluation can be by a visual or mechanical inspection, by means well known in the art. If a machined workpiece has been acceptably machined, then the modular tooling apparatus is properly aligned with the metalworking machine for performing metalworking operations on subsequent workpieces. If the machined workpiece has not been acceptably machined, then the base of the modular tooling apparatus can be re-aligned with the metalworking machine before machining a subsequent workpiece.
Another embodiment of the invention is shown in
After the last of machined first workpieces has been removed from the workpiece support feature, the first insert and second insert are removed from the base. A provided third insert, comprising a second member of the first family of inserts, is associated and secured to the first attachment surface of the base, wherein its locating feature is configured to associate with the locating feature of the first attachment surface to define a location of the workpiece support feature of the third insert relative to the base. A provided fourth insert, comprising a second member of the second family of inserts, is associated and secured to the second attachment surface of the base, wherein its locating feature is configured to associate with the locating feature of the second attachment surface to define a location of the workpiece support feature of the fourth insert relative to the base. A second member of the family of workpieces is then positioned onto and secured to the workpiece support features of the third and fourth inserts. The second workpiece assumes a characteristic position and orientation relative to the metalworking machine for machining of the workpiece. After machining the second workpiece, the machined workpiece is removed from the workpiece support features of the third and fourth inserts.
The replacement of the first set of inserts (the first members of the first and second families of inserts) with the second set of inserts (the second members of the first and second families of inserts) enables machining a second workpiece after the machining of a first workpiece without requiring a intermediate step of aligning the common base with the metalworking machine. Each member of the second set of inserts is configured, relative to corresponding member of the first set of inserts, to adjust for dimensional differences between the corresponding first and second workpiece members. The configuration differences between the corresponding inserts of the first and second sets enable the modular tooling apparatus to position the respective workpiece in the proper location and orientation for machining by the metalworking machine.
In a metalworking operation, when the production requires a change from machining workpiece 198 to workpiece 298, the technician removes inserts 50 and 60 shown in
The similarity in configuration of the workpiece support features of second insert set 150 and 160 with those of first insert set 50 and 60 enable a rapid change from a first workpiece 198 to a second workpiece 298, which is related in configuration but correspondingly different in detail. The successive metalworking operations on the first workpiece 198 and second workpiece 298 do not require re-alignment of the base 20. The use of the modular tooling apparatus of the invention with a family of insert sets inserts 50 and 60, 150 and 160, provides for machining of a family of workpieces 198, 298 without changing the base tooling, thereby avoiding steps normally required to exchange base tooling, including alignment of the base with the metalworking machine. When identical metalworking operations are required on both workpiece 198 and 298, the configuration of workpiece support features of the second set of inserts 150, 160 can be configured to position the workpiece 298 into a position for metalworking that does not require any changing in positioning of both the base and the metalworking machine. As shown in
In yet another embodiment of the invention, a modular tooling apparatus 10 has a base and inserts 250 and 260 shown in
In yet another embodiment of the invention, a workpiece 398 shown in
Insert 350 has a lower portion having a configuration similar to insert 60 shown on the right side of
Pocket 330 is configured to associate with and secure insert 350 to the base. Pocket 330 is positioned on base surface 339 of the base, and is oriented at an angle of about 45° from the base. The insert 350 is inserted into the pocket and secured therein with an extraction/locking device 370, shown in
Insertion of the workpiece onto the apparatus is typically by hand. The workpiece after machining is typically removed by an automatic ejection means known in the art. Base surface 339 can be configured with a passage 347 through which a pneumatically-actuated ejecting pin (not shown) can be thrust from within the base. After machining the workpiece, the ejecting pin is actuated to pass through an aperture 367 in the surface 377 of the insert 350. The ejecting pin contacts the blade base 396, and ejects the workpiece from the assembly.
Insert 360 has a lower portion configured similar to insert 50 shown in
The dovetail 303 of the workpiece is first positioned into insert 350, and with its airfoil supported by insert 360. Moveable insert 750 is positioned to register with the upper surface of the airfoil. Once all inserts are positioned and securing forces A and B are applied (to the dovetail and to the movable insert 750, respectively), the workpiece is secured and ready for machining.
The present invention is useful as a method for performing a metalworking operation on a family of compressor blades for a gas turbine engine When production requires a change from machining a blade 398 to a next-sized compressor blade member of the same family, the technician removes the set of inserts 350, 360 and 750 shown in
As indicated above, the base of the present invention can be made from a series of distinct laminar plates, aligned and fastened together. Such laminar plates can be aligned by drilling and reaming mating holes through two or more such plates, and then pressing dowel pins through the mating holes. Alternatively, keyways can be cut into abutting surfaces of adjacent plates, and rectangular keys inserted therein. Any other means for precisely aligning one plate with respect to an adjacent plate could be employed. The laminar plates can be conveniently fastened to each other by bolting. Bolting offers the advantage that the assembled base can be disassembled to repair or replace any of the laminar plates that had been worn or damaged in service. Other means of fastening the plates together, such as by surrounding the plates by a frame, and inserting a pair of wedges between the plates and the frame would suffice.
In the context of the present invention, a laminar base offers a convenient means for constructing a pocket having precise dimensions and accurately parallel sides therein. The portion of the base 20, shown in
An insert can also be fabricated from a series of distinct laminar plates. For example, insert 350, shown in
The invention has been described and illustrated in terms of a base having a pocket, into which an insert having a cooperating lower portion is inserted. However, is contemplated in the present invention to associate the insert with the base by others means. In other embodiments of the invention, the attachment surface can comprise a raised surface on the base which can resemble the lower portion of an insert, such as lower portion 56 of insert 50 as described for and shown in
While specific embodiments of the apparatus and method of the present invention have been described, it will be apparent to those skilled in the metalworking arts that various modifications thereto can be made without departing from the spirit and scope of the present invention as defined in the appended claims.
Number | Date | Country | |
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60437497 | Dec 2002 | US | |
60437238 | Dec 2002 | US | |
60437236 | Dec 2002 | US |
Number | Date | Country | |
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Parent | 10370869 | Feb 2003 | US |
Child | 11073506 | Mar 2005 | US |