Title: Manufacturing cell using tooling apparatus
Abstract: A manufacturing cell having a plurality of work stations, where at least one of the work station comprises a metalworking machine, and where at least one metalworking machine is provided with a modular tooling apparatus. The modular tooling apparatus consists of a base having one or more attachment surfaces, and one or more inserts that can be inserted semi-permanently to the attachment surfaces. The attachment surface is typically a pocket in the surface of the base. The insert has a workpiece support feature that can support and/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 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 invention also provides a process for performing a plurality of metalworking operations on workpieces, employing the manufacturing cell described hereinabove.
Patent Number: 6,993,821 Issued on 02/07/2006 to Ahti, et al.
| Inventors:
|
Ahti; Robert Allan (Hillsborough, NH);
Dupuis; Christian (Cincinnati, OH);
Elman; Larisa Alexandra (Swampscott, MA)
|
| Assignee:
|
General Electric Company (Schenectady, NY)
|
| Appl. No.:
|
370960 |
| Filed:
|
February 20, 2003 |
| Current U.S. Class: |
29/563; 409/225; 269/88; 269/902; 269/297; 269/309; 269/316; 269/319; 269/900; 33/573; 279/152 |
| Current Intern'l Class: |
B23P 23/00 (20060101); B23Q 3/06 (20060101) |
| Field of Search: |
29/563
409/219,225,903
269/88,900,309,329,872,902,268,99,93-94,303-306,315-319,297-301,291
33/568,573
279/152-154
408/103
|
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| |
Other References
U.S. Appl. No. 10/370,869, filed Feb. 20, 2003, Elman et al.
U.S. Appl. No. 10/370,868, filed Feb. 20, 2003, Dupuis et al.
U.S. Appl. No. 10/370,960, filed Feb. 20, 2003, Ahti et al.
|
Primary Examiner: Cadugan; Erica
Attorney, Agent or Firm: Nesbitt; Daniel F., Hasse & Nesbitt LLC
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/437,236,
filed Dec. 30, 2002; U.S. Provisional Application No. 60/437,238, filed Dec. 30,
2002; and U.S. Provisional Application No. 60/437,497, filed Dec. 30, 2002.
Claims
We claim:
1. A manufacturing cell for performing a plurality of metalworking operations
on a workpiece, wherein the manufacturing cell comprises a plurality of work stations,
and wherein at least one work station comprises:
(a) a metalworking machine; and
(b) modular tooling apparatus secured to a table of the metalworking machine,
the modular tooling apparatus comprising:
(i) a base comprising:
a means for securing the base to the table of the metalworking machine; and
an attachment surface comprising a pocket having a locating feature; and
(ii) at least one insert associated with the attachment surface by sliding into
an opening of the pocket, the at least one insert comprising a locating feature
and pocket orientation feature whereby the at least one insert can associate with
the pocket in only one orientation, and a workpiece support feature on a surface thereof;
wherein the locating feature on the at least one insert is configured to associate
with the locating feature of the attachment surface, thereby defining a location
of the workpiece support feature relative to the base.
2. The manufacturing cell according to claim 1, wherein the pocket and the at
least one insert are configured whereby the pocket restrains the movement of the
at least one insert in a plurality of directions.
3. The manufacturing cell according to claim 2, wherein the pocket is configured
to restrain the at least one insert within the pocket in all directions except
one remaining direction.
4. The manufacturing cell according to claim 3, further comprising an insert
securement for separably securing the at least one insert in the pocket.
5. The manufacturing cell according to claim 4, wherein the insert securement
is configured to move between a first position at which the at least one insert
is not secured and a second position at which the at least one insert is secured,
without use of a mechanic's tool.
6. The manufacturing cell according to claim 2, wherein the pocket and the at
least one insert are configured whereby one of the plurality of metalworking operations
exerts a force upon the at least one insert in at least one of the plurality of
restrained directions.
7. The manufacturing cell according to claim 1, wherein the attachment surface
and an associated insert are moveable relative to the base.
8. The manufacturing cell according to claim 7, further comprising a first force
means configured to apply a force upon a workpiece disposed upon the workpiece
support feature, to secure the workpiece against the workpiece support feature.
9. The manufacturing cell according to claim 8, further comprising a second force
means configured to apply upon the moveable insert a force to secure the workpiece
support feature of the moveable insert against the workpiece.
10. The manufacturing cell according to claim 1, wherein the location of the
workpiece support feature is semi-permanently fixed between successive metalworking
operations upon successive workpieces.
11. The manufacturing cell according to claim 1, wherein the at least one insert
comprises a workpiece orientation feature, whereby the workpiece can be associated
with the workpiece support feature of the at least one insert in only one orientation.
12. The manufacturing cell according to claim 1, wherein the at least one insert
comprises a first insert and a second insert, wherein the second insert is related
in general configuration, but different in detail from the first insert, the detail
being selected from size and proportion, and wherein the first and second inserts
associate alternately with the same pocket.
13. The manufacturing cell according to claim 12, wherein the respective workpiece
support features of the first and second inserts are configured to support first
and second workpieces, respectively, wherein the workpieces are related in general
configuration, but different in detail, the detail being selected from size and proportion.
14. The manufacturing cell according to claim 12, wherein the respective support
features of the first and second inserts are configured to support the same workpiece
in different positions during sequential first and second metalworking operations, respectively.
Description
FIELD OF THE INVENTION
The invention relates to the field of tooling for metalworking operations and
tooling systems for metalworking operations, and in particular, to manufacturing
cells comprising a plurality of metalworking operations clustered together in adjacent
locations on a factory floor.
BACKGROUND OF THE INVENTION
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. Where a plurality of metalworking machines is used
in a manufacturing cell, the need to simplify the tooling changeover process is
even greater. During a tooling changeover, it is necessary to change the tooling
for each metalworking machine, but in addition, all other machines in the cell
are typically idle while the tooling on any one machine is being changed.
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.
A conventional manufacturing cell 1 is shown in its general configuration
in FIG. 1. The manufacturing cell has two numerically controlled machining centers,
shown at 2 and 3, inspection equipment, shown at 4, a robot
for manipulating workpieces, shown at 5 and a control system, shown at 6.
Metalworking machines identified as machining centers typically possess the functional
attributes of a milling machine, in that a workpiece is moved past a rotating cutting
tool, and additionally possess attributes particularly suited to automation, such
as numerical control (N/C), a plurality of cutting tools housed in a magazine,
and N/C means for changing cutting tools. A manufacturing cell can contain many
different types of metalworking machines, and that there is no theoretical limit
to the number of metalworking machines and accessories that can be included in
a manufacturing cell.
A conventional milling machine 2 is illustrated in FIG. 2. The typical components
of the milling machine are: base 11, column 12, head 13, knee
14, saddle 15, table 8, spindle 16 and cutting tool
17. The customary reference axes that define directions of movement and/or
measurement are also shown in FIG. 2. Both the manufacturing cell shown in FIG.
1 and the milling machine shown in FIG. 2 are known to persons skilled in the art.
The selection of milling operations for the manufacturing cell shown in FIG. 1
and the metalworking machine shown in FIG. 2 was made solely for illustrating the
present invention, and the selection should not be regarded as a limitation on
the scope of the present invention.
Milling machines typically have a tooling means for securing the workpiece
to the table (not shown in FIG. 2). The various types of conventional tooling for
securing the workpiece to the table typically do not provide rapid changeover from
one workpiece to the next. Conventional tooling can require substantial disassembly
of the tooling to make such a changeover, and substantial time to change the tooling
from that used with one member of a family of workpieces to that used with another
family member. Each of these factors typically leads to extensive commitment of
time by highly skilled technicians to secure the next workpiece, or the next set
of tooling, to the table. Whenever a metalworking machine is idled to change either
a workpiece or tooling, it cannot perform its intended metalworking function. In
the context of a manufacturing cell, where idling any one metalworking machine
in the cell can idle other such machines in the cell, these deficiencies are particularly
important. The present invention addresses these deficiencies, particularly with
respect to manufacturing cells.
BRIEF DESCRIPTION OF THE INVENTION
The present invention provides a manufacturing cell for performing a plurality
of metalworking operations on a workpiece, wherein the manufacturing cell comprises
a plurality of work stations, and wherein at least one work station comprises a
metalworking machine and a modular tooling apparatus secured to a table of the
metalworking machine. The modular tooling apparatus comprises a base comprising
a means for securing the base to the metalworking machine and an 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. The locating feature on the insert is configured to associate
with the locating feature of the pocket, thereby defining a location of the workpiece
support feature relative to the base.
The present invention also provides a manufacturing cell for performing a plurality
of metalworking operations on a workpiece, wherein the manufacturing cell comprises
a plurality of work stations, and wherein at least one work station comprises a
metalworking machine comprising a table, and a modular tooling apparatus secured
to the table of the metalworking machine. The modular tooling apparatus comprises
a base comprising: a securement for securing the base to a table of the metalworking
machine and at least first and second pockets therein, each of the pockets having
a locating feature on a surface thereof, and at least a first set of inserts comprising
at least first and second inserts, corresponding to the first and second pockets,
respectively, each of the inserts having a locating feature and a workpiece support
feature on a surface thereof. The base also comprises an insert securement means
for separably securing each insert in its corresponding pocket. Each insert locating
feature is configured to associate with the corresponding pocket locating feature,
thereby defining a location of each workpiece support feature relative to the base.
The present invention further provides a process for performing, in a manufacturing
cell, a plurality of metalworking operations on a workpiece, the process comprising
the steps of: providing a workpiece; providing a manufacturing cell comprising
a plurality of work stations, at least one work station comprising a metalworking
machine comprising a table; providing, for at least one metalworking machine, modular
tooling apparatus for securing the workpiece in the metalworking machine; securing
the modular tooling apparatus semi-permanently to the table of the metalworking
machine; securing the workpiece in the first metalworking machine; performing a
first metalworking operation on the workpiece; removing the workpiece from the
first metalworking machine; securing the workpiece in the second metalworking machine;
performing a second metalworking operation on the workpiece; and removing the workpiece
from the second metalworking machine. The modular tooling apparatus of the process
comprises: a base comprising at least first and second pockets therein, each of
the pockets having a locating feature on a surface thereof; a set of inserts comprising
at least first and second inserts, corresponding to the first and second pockets,
respectively, each of the inserts having a locating feature and a workpiece support
feature on a surface thereof; a securement for separably securing each insert in
its corresponding pocket; and a means for separably securing the workpiece to the
modular tooling apparatus. The locating feature on each insert is configured to
associate with the locating feature in the corresponding pocket. The workpiece
support features of the inserts collectively and cooperatively support the workpiece
and define a location thereof relative to the modular tooling apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic representation of a tooling insert and a base employed therewith.
FIG. 2 shows a schematic representation of the modular tooling apparatus consisting
of the insert shown in FIG. 1 installed in the base, which is also shown in FIG.
1. A securement is shown in the foreground of the Figure. A workpiece is shown
in the upper right portion of the Figure.
FIG. 3 shows a schematic representation of a workpiece in the modular tooling
apparatus, illustrating how the workpiece can be secured in the apparatus.
FIG. 4 shows a plan view of the securement shown in FIG. 3.
FIG. 5 shows a partial schematic view of the insert shown in FIG. 1, illustrating
how the workpiece can be secured with the insert.
FIG. 6 shows a schematic representation of a workpiece in the modular tooling
apparatus after completion of the metalworking operation, and illustrating how
the workpiece can be secured in the apparatus with a movable insert of the invention.
FIG. 7 shows a schematic representation of a movable tooling insert and its
associated pocket on a movable member of the base.
FIG. 8 shows a schematic representation of the movable tooling insert of FIG.
7 inserted into the associated pocket of the movable member, also shown in FIG. 7.
FIG. 9 shows a schematic representation of another modular tooling apparatus
for machining a first workpiece, illustrating a first tooling insert associated
with its pocket, and a second tooling insert for associating with a second pocket,
and an extraction/locking device incorporated with the second pocket.
FIG. 10 shows a schematic representation of the modular tooling apparatus in
FIG. 9, with the second tooling insert installed in the base. In this Figure, the
extraction/locking device is shown in its locking position.
FIG. 11 shows a cross sectional view through the modular tooling apparatus shown
in FIG. 10. In this Figure, the second insert is shown in dashed lines.
FIG. 12 shows a schematic representation of the first workpiece in the modular
tooling apparatus of FIG. 10, illustrating how the first workpiece can be secured
in the apparatus.
FIG. 13 shows a schematic representation of the first workpiece in the modular
tooling apparatus of FIG. 12, after completion of the metalworking operation.
FIG. 14 shows a schematic representation yet another modular tooling apparatus
for machining a second workpiece, having a second set of first and second inserts
installed in the base.
FIG. 15 shows a schematic representation of the second workpiece in the modular
tooling apparatus of FIG. 14, illustrating how the second workpiece can be secured
in the apparatus.
FIG. 16 shows a schematic representation of the second workpiece in the modular
tooling apparatus of FIG. 14, after completion of the metalworking operation.
FIG. 17 shows a schematic representation of another modular tooling apparatus,
having a different combination of inserts and securements.
FIG. 18 shows a schematic representation of a workpiece that can be machined
on a modular tooling apparatus of the invention.
FIG. 19 shows a schematic representation of a modular tooling apparatus having
a plurality of inserts that associate with corresponding pockets in the base, to
support the workpiece shown in FIG. 18.
FIG. 20 shows a schematic representation of the workpiece of FIG. 18 positioned
on the modular tooling apparatus shown in FIG. 19, having inserts configured to
support the characteristic features of the workpiece.
FIG. 21 shows a schematic representation of a manufacturing cell (prior art)
showing two metalworking machines, an inspection station, a robot for manipulating
workpieces, and a control system.
FIG. 22 shows a schematic representation of a milling machine (prior art), illustrating
the customary definition of x-, y- and z-direction movement.
DETAILED DESCRIPTION OF THE INVENTION
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, the phrase "manufacturing cell" refers to a plurality of metalworking
machines, clustered together in close proximity on a factory floor. The phrase
generally comprehends accessory equipment, including but not limited to inspection
equipment, materiel handling equipment, heat treatment equipment, cleaning equipment
and the like, that can be employed in conjunction with the metalworking machines.
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 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 operations used
to manufacture metal workpieces. The improved metalworking tooling operation employs
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 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 a modular tooling apparatus of the invention is shown in FIGS.
1 and 2. FIG. 1 shows a modular tooling apparatus
10 comprising a base
20
having an attachment surface, shown as a pocket
30, and an insert
50
separated from the base
20. The base
20 is configured to be attached
semi-permanently to a metalworking machine (not shown). The head of T-bolt
23
is secured in a T-slot in a table
8 of the metalworking machine. The shank
of the T-bolt passes through a slot
24 in the base, and the T-bolt is capped
with a hexagonal nut
25 that, when turned, presses downward upon the top
surface of the base
20 to secure the base to the table
8. Several
T-bolts are commonly employed, as is common practice in the metalworking arts.
The base can be secured to the table by means well known in the art. In addition
to T-bolts mentioned above, the base can be secured to the table with: standard
threaded bolt downward through a slot in the base, engaging a T-nut in a slot in
the table, a threaded rod with a T-nut at the bottom and a standard hexagonal nut
at the top; and a C-clamp, clamping a top surface of the base with the bottom of
the table; a threaded bolt engaging a tapped hole in the table; a custom-machined
table into which the base slidably secures; and a cam-action clamp having a T-head
rod in the T-slot of the table, whereby actuating the cam causes downward pressure
against the tooling base by pulling upward against the T-head rod. Those having
ordinary skill in the metalworking arts will recognize these and alternative means
for attaching the base
20 the metalworking machine. The attachment of the
base to the table includes the step of orienting and positioning the base whereby
a reference point on the base cooperates with a reference point on the metalworking
machine to define a position of the base relative to the metalworking machine.
The fixed reference point can include one or more points on the base. The fixed
references typically include a spherical device attached to the base
20
and a removable electronic indicating system temporarily attached to the spindle
of the metalworking machine (not shown). Alternatively, a manual method of orienting
and positioning the base can be employed. The manual method, well known in the
machining arts, relies upon a dial indicator temporarily secured to a fixed feature
of the metalworking machine while the indicator arm rests upon an appropriate linear
or planar feature of the base. The table is then moved so that multiple readings
are obtained from various locations of the linear or planar feature relative to
the fixed feature. Those having ordinary skill in the metalworking arts will recognize
these and alternative means for providing an indication of the location thereof
to a control system that can be employed in operating the machine.
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 FIG. 1 has a backwall
35,
a rear sidewall
34, an opposed front sidewall, and a floor
33. The
sidewalls are typically parallel to each other, and perpendicular to the backwall.
Each wall is typically perpendicular to the floor
33. The front and rear
sidewalls have overhanging ledges
37 and
38, respectively, with a
clearance recess there below.
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 FIG. 5. These support surfaces
support corresponding surfaces on the workpiece
98 as shown in FIG. 4. Insert
50 is configured to define a location of the workpiece support feature relative
to the insert locating point
51. The workpiece support members
71,
72, and
73 are precisely machined to provide characteristic positioning
(in the x, y and z coordinate space) of the workpiece support feature relative
to the insert locating point
51.
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.
FIG. 2 shows the modular tooling apparatus
1 with the insert
50
inserted into and associated with the pocket
30. The insert
50 is
restrained from movement within the pocket
30 in a plurality of directions,
namely in the both z directions, both y directions, and in the -x direction. Thus,
the insert is unrestrained by the pocket in the all directions except the one remaining
direction, the +x direction, from which the insert
50 has been inserted.
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 a modular tooling apparatus used in the present invention
shown in FIG. 2, a securement
90 is associated with the modular tooling
apparatus to separably secure the insert in the pocket. The securement
90
comprises a pivot
91 and a body
92 that can move pivotally from a
first position where the insert can be inserted and removed from the pocket, and
a second position where the securement restrains the insert from movement within
the pocket in the +x direction, shown in FIG. 3. FIGS. 3 and 4 show the securement
body
92 can comprise a biasing member comprising an elongated biasing member
93 that extends away from and along the wall of the body
92 confronting
the insert. In the first (unsecured) position, the biasing member
93 projects
into the plane of the front wall
57 of the insert. When the securement is
in the second position, the biasing member
93 is forced to bend inward toward
the securement body
92. Due to the resilience to bending of its material
(typically a tool steel), the biasing member
93 exerts a biasing force against
the front wall
57 to secure the insert in position. The securement is provided
with a handle
94 to assist moving the body between positions. Typically
the securement
90 is configured to be manipulated between its first and
second positions without the use of a mechanic's tool.
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 FIG. 2, the rear toe
59 of
lower portion
56 can enter the pocket within the corresponding clearance
of the opening
36 under rear ledge
38. If the insert is turned 180°,
the height of the same rear toe
59 prevents insertion within the shorter
clearance of the opening under front ledge
37. This feature prevents a user
of the apparatus from inserting the insert
50 improperly into pocket
30.
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 FIG. 2, the workpiece
orientation feature comprises shoulder
106 that extends upwardly from the
support surface comprising workpiece support member
72. The shoulder
106
is configured to register with a flat
611 of a workpiece
98 that
has been machined along edge
615 only of the workpiece body. The shoulder
106 is also configured to prevent placement of the workpiece upon the support
members
71 and
72 if the workpiece is placed into the apparatus in
any of the other three orientations where body edges
613,
614 or
616 confront the shoulder
106.
FIG. 2 shows a workpiece
98 separated from the insert
50. The
workpiece
98 comprises a rectilinear body
601 having a square cross
section, and a ball joint
602 affixed to a first end of the body. The ball
joint
602 comprises a spherical head
603 adjoined to the body
601
by a cylindrical neck
604. The head
603 and neck
604 are aligned
with the centerline
610 of the workpiece. The workpiece has flat
611
having a face
612 that has been machined in a prior metalworking operation
along a portion of edge
615 of the body
601. The face
612
is a planar surface that lies parallel to a plane passing through workpiece edges
613 and
614. Such a workpiece can be conveni
