U.S. patent application number 15/200087 was filed with the patent office on 2017-01-12 for machining apparatus and machining method.
This patent application is currently assigned to FUJI JUKOGYO KABUSHIKI KAISHA. The applicant listed for this patent is FUJI JUKOGYO KABUSHIKI KAISHA, FUYO JITSUGYO CO. LTD.. Invention is credited to Yuichi ISHIKAWA, Yasushi MIYASHITA, Atsushi RIHEI, Saichiro YAMASHITA.
Application Number | 20170008102 15/200087 |
Document ID | / |
Family ID | 57730434 |
Filed Date | 2017-01-12 |
United States Patent
Application |
20170008102 |
Kind Code |
A1 |
ISHIKAWA; Yuichi ; et
al. |
January 12, 2017 |
MACHINING APPARATUS AND MACHINING METHOD
Abstract
According to one implementation, a machining apparatus includes
an electromotive saw and an attaching structure. The electromotive
saw cuts off a workpiece to be machined. The attaching structure
attaches the saw to an arm of a robot. Further, according to one
implementation, a machining method is provided. In the machining
method, a machined product is manufactured by processing a
composite material or a honeycomb structure with a cutting tool
attached to an arm of a robot. Further, according to one
implementation, a machining method is provided. In the machining
method, a machined product is manufactured by processing a
workpiece to be machined with a cutting tool attached to an arm of
a robot. The workpiece is processed along a shape of a jig for
setting the workpiece. The workpiece is processed with contacting a
guide with the jig. The guide is attached to the arm.
Inventors: |
ISHIKAWA; Yuichi; (Tokyo,
JP) ; RIHEI; Atsushi; (Tokyo, JP) ; YAMASHITA;
Saichiro; (Yamanashi, JP) ; MIYASHITA; Yasushi;
(Yamanashi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJI JUKOGYO KABUSHIKI KAISHA
FUYO JITSUGYO CO. LTD. |
Tokyo
Yamanashi |
|
JP
JP |
|
|
Assignee: |
FUJI JUKOGYO KABUSHIKI
KAISHA
Tokyo
JP
FUYO JITSUGYO CO. LTD.
Yamanashi
JP
|
Family ID: |
57730434 |
Appl. No.: |
15/200087 |
Filed: |
July 1, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23D 57/0053 20130101;
G05B 2219/50167 20130101; B64F 5/10 20170101; G05B 2219/45044
20130101; B25J 11/0055 20130101; B23D 53/00 20130101; Y10S 901/09
20130101; G05B 2219/49195 20130101; B25J 9/1694 20130101; B23D
55/06 20130101; B25J 13/085 20130101; G05B 2219/50125 20130101;
B23D 57/02 20130101 |
International
Class: |
B23D 55/06 20060101
B23D055/06; B23D 57/00 20060101 B23D057/00; B23D 57/02 20060101
B23D057/02; B64F 5/00 20060101 B64F005/00; B23Q 17/09 20060101
B23Q017/09; B25J 11/00 20060101 B25J011/00; B25J 13/08 20060101
B25J013/08; B25J 9/16 20060101 B25J009/16; B23D 53/00 20060101
B23D053/00; B23Q 9/00 20060101 B23Q009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2015 |
JP |
2015-138137 |
Claims
1. A machining apparatus comprising: an electromotive saw that cuts
off a workpiece to be machined; and an attaching structure that
attaches the saw to an arm of a robot.
2. The machining apparatus according to claim 1, further
comprising: a guide for copying processing along a shape of a jig
for setting the workpiece to be machined, the copying processing
being performed by contacting the guide with the jig.
3. The machining apparatus according to claim 1, further comprising
the robot.
4. The machining apparatus according to claim 2, further comprising
the robot.
5. The machining apparatus according to claim 2, further
comprising: the robot; a sensor that measures a force applied on
the guide from the jig; and a control circuit that performs a
feedback control of the robot, based on a measurement result by the
sensor, to make the force applied on the guide from the jig be
constant.
6. A machining method, wherein a machined product is manufactured
by processing a composite material or a honeycomb structure with a
cutting tool attached to an arm of a robot.
7. A machining method, wherein a machined product is manufactured
by processing a workpiece to be machined with a cutting tool
attached to an arm of a robot, the workpiece being processed along
a shape of a jig for setting the workpiece, the workpiece being
processed with contacting a guide with the jig, the guide being
attached to the arm.
8. A machining method according to claim 6, wherein the machined
product is manufactured by processing a workpiece to be machined
with the cutting tool along a shape of a jig for setting the
workpiece, the workpiece being processed with contacting a guide
with the jig, the guide being attached to the arm, the workpiece
being made of the composite material or the honeycomb
structure.
9. A machining method according to claim 7, wherein a force applied
on the guide from the jig is measured by a sensor, and feedback
control of the robot is performed to make the force applied on the
guide from the jig be constant.
10. A machining method according to claim 8, wherein a force
applied on the guide from the jig is measured by a sensor, and
feedback control of the robot is performed to make the force
applied on the guide from the jig be constant.
11. A machining method according to claim 6, wherein a tolerance of
the machined product is from .+-.0.1 mm to .+-.1.0 mm.
12. A machining method according to claim 7, wherein a tolerance of
the machined product is from .+-.0.1 mm to .+-.1.0 mm.
13. A machining method according to claim 8, wherein a tolerance of
the machined product is from .+-.0.1 mm to .+-.1.0 mm.
14. A machining method according to claim 6, wherein the processing
is machining processing, including cutting of the composite
material or the honeycomb structure with an electromotive band saw,
wire saw, jigsaw or chain saw.
15. A machining method according to claim 7, wherein the processing
is machining processing, including cutting of the composite
material or the honeycomb structure with an electromotive band saw,
wire saw, jigsaw or chain saw.
16. A machining method according to claim 8, wherein the processing
is machining processing, including cutting of the composite
material or the honeycomb structure with an electromotive band saw,
wire saw, jigsaw or chain saw.
17. A machining method according to claim 14, wherein the composite
material or the honeycomb structure is cut off with inclining the
band saw, the wire saw, the jigsaw or the chain saw by 1 degree to
30 degrees in a direction of a forward movement.
18. A machining method according to claim 15, wherein the composite
material or the honeycomb structure is cut off with inclining the
band saw, the wire saw, the jigsaw or the chain saw by 1 degree to
30 degrees in a direction of a forward movement.
19. A machining method according to claim 6, wherein a position of
the arm is controlled based on a reference position detected by a
visible sensor.
20. A machining method according to claim 7, wherein a position of
the arm is controlled based on a reference position detected by a
visible sensor.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2015-138137, filed on
Jul. 9, 2015; the entire contents of which are incorporated herein
by reference.
FIELD
[0002] Implementations described herein relate generally to a
machining apparatus and a machining method.
BACKGROUND
[0003] As a material for a part, such as an aircraft part, which
requires high strength and weight saving, a composite material or a
honeycomb structural body is conventionally used. As a method for
manufacturing a part, having a predetermined shape, from a material
consisting of a composite material or a honeycomb structural body,
a machining process using a cutting tool, such as an end mill, is
mentioned.
[0004] For example, when an aircraft part, such as a panel, made by
a composite material, is manufactured, an end mill is attached to a
column type machine tool, such as a milling machine or a machining
center, and machining process, such as outline machining, is
performed (for example, refer to Japanese Patent Application
Publication JP2013-244556A). On the other hand, when an aircraft
part made by a honeycomb structural object is manufactured, a
honeycomb core material having a predetermined size is cut out by a
saw, such as a commercially available bandsaw or metal slitting saw
beforehand, and finishing processing of an outline, a surface and
the like is performed by manual work using hand tools or by
machining process using a column type machine tool (for example,
refer to Japanese Patent Application Publication
JP2002-18629A).
[0005] An object of the present invention is to enable it to
machine a part, such as composite material or a honeycomb
structure, at lower cost.
SUMMARY OF THE INVENTION
[0006] In general, according to one implementation, a machining
apparatus includes an electromotive saw and an attaching structure.
The electromotive saw cuts off a workpiece to be machined. The
attaching structure attaches the saw to an arm of a robot.
[0007] Further, according to one implementation, a machining method
is provided. In the machining method, a machined product is
manufactured by processing a composite material or a honeycomb
structure with a cutting tool attached to an arm of a robot.
[0008] Further, according to one implementation, a machining method
is provided. In the machining method, a machined product is
manufactured by processing a workpiece to be machined with a
cutting tool attached to an arm of a robot. The workpiece is
processed along a shape of a jig for setting the workpiece. The
workpiece is processed with contacting a guide with the jig. The
guide is attached to the arm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the accompanying drawings:
[0010] FIG. 1 is a perspective view showing a structure of a
machining apparatus according to an implementation of the present
invention;
[0011] FIG. 2 is a perspective view of an end part of a robot arm,
an attaching mechanism and an electromotive saw, shown in FIG. 1,
as viewed from another direction;
[0012] FIG. 3 is a front view of a band saw shown in FIG. 1;
[0013] FIG. 4 is a view for explaining an example case of
chamfering a honeycomb core by cutting processing with the saw
2;
[0014] FIG. 5 is a view showing an example of guide for securing
processing accuracy of the machining apparatus;
[0015] FIG. 6 is a bottom view showing the first modification of
shapes of the block of the jig and the projection in the band saw
side shown in FIG. 5;
[0016] FIG. 7 is a bottom view showing the second modification of
shapes of the block of the jig and the projection in the band saw
side shown in FIG. 5;
[0017] FIG. 8 is a top view showing an example of composite
material panel to be machined by the machining apparatus shown in
FIG. 1; and
[0018] FIG. 9 is a side view of the composite material panel shown
in FIG. 8.
DETAILED DESCRIPTION
[0019] A machining apparatus and a machining method according to
implementations of the present invention will be described with
reference to the accompanying drawings.
(Structure and Function)
[0020] FIG. 1 is a perspective view showing a structure of a
machining apparatus according to an implementation of the present
invention. FIG. 2 is a perspective view of an end part of a robot
arm, an attaching mechanism and an electromotive saw, shown in FIG.
1, as viewed from another direction. FIG. 3 is a front view of a
band saw shown in FIG. 1.
[0021] A machining apparatus 1 includes an electromotive saw 2, for
cutting a workpiece W to be machined, which is attached to a robot
4 by an attaching mechanism 3. In the illustrated example, a band
saw 5 is used as the electromotive saw 2. As a matter of course,
another electromotive saw 2, such as a wire saw, a jigsaw, or a
chain saw may be used.
[0022] The electromotive band saw 5 is a power tool which is driven
by rotating a belt-shaped and ringed blade 5A, having an edge, with
pulling the ringed blade 5A from an inner side with not less than
two pulleys 5B. Accordingly, a motor 5C is prepared in the band saw
5 as a power source for rotating the pulleys 5B. In the illustrated
example, the two pulleys 5B have been placed in a casing 5D of the
band saw 5, and the band saw 5 has been configured so that a part
of the blade 5A may pass through the outside of the casing 5D while
the blade 5A rotates. Therefore, a workpiece W to be machined is to
be cut by a linear part of the blade 5A passing through the outside
of the casing 5D.
[0023] An electromotive wire saw is a power tool which is driven by
rotating a ringed cutting wire, to which diamond particles or the
like have adhered, with pulling the ringed cutting wire from an
inner side with not less than two pulleys. A wire saw has an
advantage that the cutting direction can be changed easily because
of freeness from the cutting direction. A jigsaw is a power tool
which cuts a workpiece W to be machined by reciprocating a blade
having an edge. A chain saw is a power tool which cuts a workpiece
W to be machined by rotating a chain, having many blades, along the
outer periphery of a plate with power.
[0024] The robot 4 is a driving mechanism, such as a jointed-arm
robot, which has an arm 7 which drives by a power source 6, such as
a motor. In the illustrated example, a jointed-arm robot in which
many joints can be rotated with a link mechanism has been used. As
a matter of course, a simple robot which has a single drive axis
may be used, and alternatively a robot which has plural drive axes
may be used.
[0025] For example, a commercially available jointed-arm robot
disclosed on Japanese Patent Application Publication JP2011-41992
or the like may be used as the robot 4 of the machining apparatus
1. Note that, a general-purpose machining apparatus 1 may be
composed of the electromotive saw 2 and the attaching mechanism 3
so that the electromotive saw 2 can be attached to various robots
to be used, instead of installing the robot 4 itself as a
component. In that case, the machining apparatus 1 is a power tool
which can be attached with a desired robot by the attaching
mechanism 3.
[0026] The robot 4 is controlled by a control circuit 8. The
control circuit 8 can be configured by processing circuitry, such
as a processor, which executes control program of the robot 4.
Moreover, an input circuit 8A and a display 8B are connected to the
control circuit 8, as needed.
[0027] The attaching mechanism 3 is an attachment for attaching the
saw 2 with the arm 7 of the robot 4. Thereby, it becomes possible
to cut a workpiece W to be machined with attaching the saw 2 with a
multijoint robot or the like. In the example shown in the figures,
the attaching mechanism 3 having structure in which attaching
implements 3C to be attached to the arm 7 are disposed on a rod 3B
and attaching implements 3A for attaching the saw 2 are disposed at
the both ends of the rod 3B has been used as an attachment.
[0028] Note that, machining of a workpiece W to be machined may
include cutting other than scission. For that reason, the attaching
mechanism 3 can have structure which can be attached to and
detached from the arm 7 of the robot 4. Thereby, it becomes
possible to perform a variety of machining process by attaching
different kinds of electric power tools to the arm 7 of the robot
4.
[0029] As a practical example, when an attaching mechanism for
attaching a tool, such as an end mill or a drill, which performs
cutting processing with rotating the tool around a tool axis, to
the arm 7 of the robot 4 is prepared, it becomes possible to
perform outline finish processing and/or surface finish processing
with end mills after cutting a workpiece W to be machined off with
the saw 2, or conversely, cut a workpiece W to be machined off with
the saw 2 after performing milling with end mills. That is, a
removable jig for attaching the saw 2 to the arm 7 of the robot 4
and a removable jig for attaching another tool, such as an end
mill, to the arm 7 of the robot 4 can be prepared so that they can
be exchanged.
[0030] When at least the saw 2 is attached to the arm 7 of the
robot 4, not only machining of a metal plate material and a metal
block material, but also machining of a composite material, such as
GFRP (glass fiber reinforced plastics) or CFRP (carbon fiber
reinforced plastics), and machining of a honeycomb structure made
of a composite material or a metal can be performed at low cost by
the machining apparatus 1.
[0031] For example, when machining process is performed using a
column type machine tool having a large scale, extensive work for
installation of the machine tool and construction of a building
which has a width for placing the machine tool are necessary. By
contrast, when the machining apparatus 1 to which an electric power
tool, such as the saw 2, has been attached to the arm 7 of the
robot 4 is used, it is possible to considerably reduce the scale,
cost, and occupied area of the machining apparatus 1, compared to
the case where a machine tool is installed.
[0032] In addition, when a cut margin removed by machining process
is large and a surface after the machining is a flat or a two
dimensional curved surface, a processing time can be shortened by
cutoff processing using the saw 2 instead of milling using end
mills. As a specific example, in the case of chamfer processing for
forming a C chamfer or outline processing, a surface after the
processing becomes a flat or a two dimensional curved surface.
Therefore, when a cut margin is large, severing processing by the
saw 2 can increase efficiency of machining process.
[0033] FIG. 4 is a view for explaining an example case of
chamfering a honeycomb core by cutting processing with the saw
2.
[0034] As shown in FIG. 4, in the case of forming a chamfer on a
honeycomb core W1, moving the blade 5A of the band saw 5 in
parallel according to an angle of the chamfer requires the least
amount of processing for forming the chamfer on the honeycomb core
W 1. Specifically, it becomes possible to dramatically reduce the
amount of cutting, compared to the case of cutting the honeycomb
core W1 using an end mill. As a result, a processing time required
for chamfer processing can be shortened. As a matter of course, not
only limited to chamfer processing of the honeycomb core W1 but the
similar applies to the case of chamfer processing of a block
material or a plate material consisting of a composite material or
a metal.
[0035] When the arm 7 of the robot 4 has necessary drive axes, an
angle of the blade 5A can also be changed during cutting.
Furthermore, when a wire saw is used as the saw 2, a cutting
direction can be changed during cutting. Thus, when the machining
apparatus 1 is used, not only flat surface processing but also
curved surface processing can be performed. As a practical example,
outline processing of a panel made of a metal, a composite
material, or a honeycomb core can be performed.
[0036] Note that, positioning accuracy of an arm of a multijoint
robot is extremely low compared to positioning accuracy of the main
spindle of a machine tool since the arm of the multijoint robot has
a cantilever structure. For example, in the case of a machine tool,
a tool can be positioned with a pitch from 0.01 mm to 0.001 mm. By
contrast, positioning accuracy similar to that of a machine tool
cannot be easily obtained for a multijoint robot because of
dispersion in the positioning accuracy of the multijoint robot.
[0037] In general, a tolerance corresponding to an accuracy
required for an aircraft part, such as a spar, a rib, a panel, and
a stringer, is from .+-.0.1 mm to .+-.1.0 mm. Therefore, when
machining process is performed by automatic control of a multijoint
robot, a required tolerance may not be satisfied due to dispersion
in processing accuracy. That is, when machining process is
performed merely by automatic control of a multijoint robot, it is
difficult to satisfy design requirements of an aircraft part
stably. This is the reason a machine tool has been conventionally
used for machining process of a part, such as an aircraft part,
which requires the accuracy.
[0038] Actually, in the case of performing outline processing of a
composite material, outline processing of a honeycomb structure,
chamfer processing of a composite material, chamfer processing of a
honeycomb structure or the like in the condition that a machine
tool could not be used, a worker conventionally performed crude
processing with a hand tool, such as a band saw or a metal saw, and
subsequently, it was necessary to manually perform finish
processing.
[0039] For that reason, the machining apparatus 1 can have a guide
for securing processing accuracy.
[0040] FIG. 5 is a view showing an example of guide for securing
processing accuracy of the machining apparatus 1.
[0041] A workpiece W to be machined is often set on a jig J as
exemplified in FIG. 5. Thus, a guide 9 for performing copying
processing along the shape of the jig J for setting the workpiece W
to be machined by making the guide 9 contact with the jig J can be
attached directly or indirectly to the arm 7 of the robot 4. For
example, the guide 9 can be formed to the saw 2 or the attaching
mechanism 3 which moves by a drive of the arm 7. In this case, the
shape and structure of the jig J are also to be designed according
to the shape and structure of the guide 9 so that copying
processing of the workpiece W to be machined can be performed by
making the guide 9 contact with the jig J.
[0042] In the example shown in FIG. 5, a honeycomb core W1 has been
set, as the workpiece W to be machined, on the jig J for chamfer
processing. On the other hand, a projection 9A is formed, as the
guide 9, to a portion of the casing 5D of the band saw 5 which
comes close to the jig J as the blade 5A of the band saw 5 has been
inclined according to an angle of a chamfer. The jig J also has a
bar shaped block J1, whose cross section is rectangular, as a guide
for making the jig J contact with the projection 9A in the band saw
5 side. Therefore, when the arm 7 is moved with making the
projection 9A in the band saw 5 side contact with the block J1 of
the jig J, the blade 5A of the band saw 5 can be moved according to
the shape of the chamfer with sufficient positioning accuracy.
[0043] That is, the jig J has the block J1 as a rail which guides
the projection 9A in the band saw 5 side. Thereby, the band saw 5
can be moved along the block J1 which functions as a rail. Note
that, similar copying processing is possible when a groove into
which the projection 9A in the band saw 5 side fits is formed in
the jig J.
[0044] An inclined angle of a chamfer of the honeycomb core W1 may
not be constant. In such a case, changing also a direction of the
band saw 5 according to the inclined angle of the chamfer of the
honeycomb core W1 leads to efficient cutting processing. For that
reason, when an inclined angle of a chamfer of the honeycomb core
W1 is not constant, the shape of the block J1 can be determined so
that a direction of the band saw 5 changes according to the
inclined angle of the chamfer of the honeycomb core W 1. That is,
copying processing with changing the inclined angle of the band saw
5 can be performed by appropriately designing the shape of the
projection 9A in the band saw 5 side and the shape of the block J1
of the jig J.
[0045] FIG. 6 is a bottom view showing the first modification of
shapes of the block J1 of the jig J and the projection 9A in the
band saw 5 side shown in FIG. 5.
[0046] For example, the shape of the block J1 of the jig J can
include a projection whose end part is circular as viewed from the
lower surface side, as shown in FIG. 6. Meanwhile, according to the
shape of the block J1, the projection 9A in the band saw 5 side can
have a concave whose curvature is similar to that of the circular
projection of the block J1. Then, it becomes possible to move the
projection 9A in the band saw 5 side in a curved line by rotating
the projection 9A along the circular projection of the block J1.
Thereby, copying processing along the block J1 of the jig J can be
performed with a change of an inclined angle of the band saw 5.
[0047] FIG. 7 is a bottom view showing the second modification of
shapes of the block J1 of the jig J and the projection 9A in the
band saw 5 side shown in FIG. 5.
[0048] For example, the shape of the block J1 of the jig J can
include a projection whose end part has a circular concave, as
shown in FIG. 7. Meanwhile, according to the shape of the block J1,
the projection 9A in the band saw 5 side can have a circular end
part whose curvature is similar to that of the circular concave of
the block J1. Then, it becomes possible to rotationally move the
projection 9A in the band saw 5 side along the circular concave of
the block J1. Thereby, copying processing along the block J1 of the
jig J can be performed with a change of an inclined angle of the
band saw 5.
[0049] As a matter of course, the shape of the block J1 of the jig
J and the shape of the projection 9A in the band saw 5 side can be
designed not only in the shapes exemplified in FIG. 6 and FIG. 7
but also in various shapes so as to maintain a relationship between
a rail and a guide.
[0050] In addition, not only the processing example of the
honeycomb core W1 shown in FIG. 5 but also in the case of outline
processing of a panel or the like, copying processing of an outline
can be performed by producing the jig J according to the outline of
the panel. Furthermore, copying processing using the jig J and the
guide 9 can be similarly performed also when a cutting tool, such
as an end mill, other than the saw 2 has been attached to the arm 7
of the robot 4.
[0051] That is, a workpiece W to be machined made of a metal, a
composite material, a honeycomb structure or the like can be
processed along a shape of the jig J for setting the workpiece W,
by a cutting tool attached to the arm 7 of the robot 4, with making
the guide 9 directly or indirectly attached to the arm 7 contact
with the jig J.
[0052] By such copying processing using the jig J and the guide 9,
even a machined product whose tolerance is from .+-.0.1 mm to
.+-.1.0 mm can be manufactured in accuracy satisfying the
tolerance. Thereby, the machining apparatus 1 can automatically
perform not only crude processing of a workpiece W to be machined
but also finish processing of that.
[0053] In the case of performing copying processing using the jig J
and the guide 9, it is effective to equip a pressure sensor 10 with
the robot 4. The pressure sensor 10 measures force applied on the
arm 7 of the robot 4. Therefore, the pressure sensor 10 can be
attached with the arm 7. When the arm 7 has plural drive axes, it
is practical to compose the pressure sensor 10 by combining plural
sensors with each other so that respective pressures in plural
directions can be measured individually.
[0054] When the pressure sensor 10 is equipped with the robot 4,
force applied on the guide 9 from the jig J can be indirectly
measured as force applied on the arm 7. Therefore, while force
applied on the guide 9 from the jig J can be measured by the
pressure sensor 10, feedback control of the robot 4 can be
performed so that the force applied on the guide 9 from the jig J
becomes constant.
[0055] That is, the control circuit 8 can have a function to
perform feedback control of the robot 4 based on a measurement
result by the pressure sensor 10 so that the force applied on the
guide 9 from the jig J becomes constant. The control circuit 8
usually has a function to control the arm 7 by control program
which instructs a moving amount from a certain position of the arm
7 to the next position of the arm 7, as an increment value
relatively. Therefore, for example, the control circuit 8 can have
a function to correct a control position of the arm 7, determined
by the control program, based on a measured value of pressure by
the pressure sensor 10 so that a load applied on the arm 7 becomes
constant. In this case, an actual movement path of the electric
power tool, such as the arm 7 and the saw 2, lies on positions
derived by correcting control positions determined by the control
program, by the feedback control.
[0056] As described above, copying processing, such as outline
processing, can be performed with pressing the blade 5A of the band
saw 5 or a tool, such as an end mill, against the jig J which has a
shape according to a processing shape of a workpiece W to be
machined, with constant force using the pressure sensor 10, instead
of automatic control based on data representing a geometric shape
of the workpiece W to be machined. Thereby, copying processing
using the jig J and the guide 9 can be performed stably.
[0057] A commercially available multijoint robot often has a
pressure sensor for recognizing whether an object has been gripped
by a hand, as a standard specification, in the case of attaching a
hand for gripping an object with the arm. A pressure sensor for
sensing gripping force by a hand attached with an arm is usually
disposed at the first joint of the arm, and is configured to be
able to sense pressures in three axis directions. In such a case,
force applied toward the guide 9 from the jig J can be measured as
a vector using a pressure sensor in three axis directions, which is
included in a multijoint robot as a standard specification.
[0058] A control value of force applied toward the guide 9 from the
jig J can be determined as an appropriate value for every workpiece
W to be machined, empirically or theoretically by processing tests
or computer simulations. A pressure at the time of making the guide
9 contact with the jig J was actually measured by the pressure
sensor 10, and copying processing of the jig J was performed with
feedback control so that about 5 kg of load was applied in the arm
7 side. As a result, it has been confirmed that a workpiece W to be
machined can be processed in sufficient accuracy.
[0059] When pressures in two axis directions or three axis
directions can be sensed by the pressure sensor 10, not only the
pressure applied on the guide 9 from the jig J but also cutting
resistance can be measured as a pressure in a direction of a
forward movement of a cutting tool, such as the saw 2. Cutting
resistance tends to increase with wear of a cutting tool.
Accordingly, a degree in wear and replacement time of a cutting
tool can be perceived by measurement of cutting resistance.
[0060] In that case, the control circuit 8 can have a function to
obtain and display an index expressing a degree of wear of a
cutting tool or a function to notify a replacement time of the
cutting tool, based on a measured value of a pressure in a
traveling direction of the cutting tool, obtained from the pressure
sensor 10. For example, a measured value itself of a pressure in a
traveling direction of a cutting tool can be displayed on the
display 8B as an index expressing a degree of wear of the cutting
tool. Alternatively, a threshold may be set to a measured value of
a pressure in a traveling direction of a cutting tool, and when a
measured value of the pressure in the traveling direction of the
cutting tool has become not less than the threshold or has exceeded
the threshold, it can be determined that a replacement time of the
cutting tool has come and coming of the replacement time can be
output to the display 8B.
[0061] Some methods for improving positioning accuracy using the
jig J, the guide 9, and the pressure sensor 10 have been described
thus far. Alternatively, positioning accuracy may be improved by
another method. As a specific example, there is a method of
controlling a position of the arm 7 based on a reference position
detected by at least one visible sensor 11 disposed on the
machining apparatus 1.
[0062] The visible sensor 11 is an image sensor, such as an optical
camera or an infrared camera. The visible sensor 11 can be disposed
on a desired position. As a specific example, the first visible
sensor 11A can be disposed on the arm 7 of the robot 4 while the
second visible sensor 11B can be disposed on a position at which a
relative positional relationship of a workpiece W to be machined,
the saw 2, and the arm 7 can be sensed. Then, the first visible
sensor 11A can sense the saw 2, which has been attached to the arm
7, and the workpiece W to be machined while the second visible
sensor 11B can sense a relative positional relationship of the
workpiece W to be machined, the saw 2, and the arm 7.
[0063] It is practical to control the arm 7 using the first visible
sensor 11A attached to the arm 7, i.e., the first visible sensor
11A which moves with a tool, such as the saw 2, from a viewpoint of
controlling a position of the arm 7 more accurately. For that
reason, the arm 7 can be positioned using the first visible sensor
11A attached to the arm 7.
[0064] FIG. 8 is a top view showing an example of composite
material panel to be machined by the machining apparatus 1 shown in
FIG. 1, and FIG. 9 is a side view of the composite material panel
shown in FIG. 8.
[0065] As shown in FIG. 8 and FIG. 9, when a curved platy composite
material panel W2 is a workpiece W to be machined, the composite
material panel W2 can be fixed with the jig J with a clamp or a
vacuum chuck. Furthermore, one hole or a plurality of holes can be
formed as a reference position or reference positions in at least
one of the jig J and an excess thickness of the composite material
panel W2.
[0066] Then, each hole formed in at least one of the jig J and the
excess thickness of the composite material panel W2 can be detected
using the first visible sensor 11 A attached to the arm 7. In
addition, an outline of at least one of the jig J and the composite
material panel W2 can also be detected using the first visible
sensor 11A.
[0067] Thus, a position of the composite material panel W2 before
processing can be specified on the basis of at least one of a
position of each hole and the outline detected using the first
visible sensor 11A. Thereby, a position of the arm 7 can be
corrected based on the position of the composite material panel W2
before processing.
[0068] Note that, instead of a hole, a point or a mark which serves
as a land mark may be engraved on at least one of the jig J and the
excess thickness of the composite material panel W2, or a point or
a mark which serves as a land mark may be displayed on at least one
of the jig J and the excess thickness of the composite material
panel W2.
[0069] In the example shown in the figures, the composite material
panel W2 before processing has two tabs W3, and each of the two
tabs W3 has a hole. Therefore, the holes of the tabs W3 and the
outline of the composite material panel W2 before processing can be
used as references. For example, the hole of one tab W3 can be
detected by the first visible sensor 11A, and copying processing
can be performed along the outline of the composite material panel
W2 from a position where the arm 7 has been moved by a certain
amount of offset from the hole of the tab W3. Alternatively, the
positions of the two holes can be previously detected before
processing by the first visible sensor 11A, and a moving path of
the arm 7 can also be geometrically determined based on design
information of the composite material panel W2 and the positions of
the two holes.
[0070] When a land mark, such as a hole, cannot be formed in either
a workpiece W to be machined or the jig J, a linear outline of the
workpiece W to be machined or the jig J can be used as a reference
for correcting a position of the arm 7. For example, a linear
outline of a workpiece W to be machined or the jig J can be
detected using the first visible sensor 11A, and a position of a
straight line having an offset from the detected linear outline can
be a control position of the arm 7. In this case, an amount of
offset can be geometrically determined based on design information
of the workpiece W to be machined. As another method, a position of
a workpiece W to be machined may be specified by detecting at least
two linear outlines of the workpiece W to be machined or the jig J.
In this case, a variety of processing, such as curve processing,
can be performed based on design information of the workpiece W to
be machined.
[0071] In the case of controlling the arm 7 using the first visible
sensor 11A, the control circuit 8 has a function to determine a
control position of the arm 7 based on image information acquired
by the first visible sensor 11A. As a specific example, the control
circuit 8 has a function to detect an outline and a position of a
marker of a workpiece W to be machined or the jig J by image
processing, such as outline extraction processing, threshold
processing, and/or image recognition processing, of image data
acquired by the first visible sensor 11A, and determine a moving
path of the arm 7 based on previously given design information of
the workpiece W to be machined. Furthermore, in the case of
performing copying processing along an outline of a workpiece W to
be machined or the jig J detected using the first visible sensor
11A, the control circuit 8 has a function to detect the outline of
the workpiece W to be machined or the jig J by image processing of
image data acquired by the first visible sensor 11A, and perform
feedback control of a position of the arm 7 along the detected
outline.
[0072] As described above, when the arm 7 is controlled based on
image data acquired by the first visible sensor 11A, positioning
accuracy of the arm 7 can be improved even when the jig J is not
used or it is difficult to make the guide 9 contact with the jig
J.
[0073] In particular, a commercially available multijoint robot
occasionally has a visible sensor in an arm, as a standard
specification, in addition to a pressure sensor. A visible sensor
is included in a commercial multijoint robot for recognizing an
object held by a hand when a hand has been attached with an arm. In
such a case, the visible sensor included in the multijoint robot
can be used for positioning in machining process.
[0074] At the time of cutting test before mass production
processing of a workpiece W to be machined, it is desired to enable
to check a situation where the workpiece W to be machined is being
processed safely. For that reason, a workpiece W to be machined, a
tool, such as the saw 2, and the arm 7 can be imaged by the second
visible sensor 11B of which imaging field of view covers the arm 7,
and can be displayed on the display 8B or another display. Thereby,
it becomes possible to process the workpiece W to be machined with
checking a relative positional relationship of the workpiece W to
be machined, a tool, such as the saw 2, and the arm 7 through an
image at the time of cutting test or the like
(Operation and Action)
[0075] Next, a machining method for manufacturing a machined
product using the machining apparatus 1 will be described.
[0076] Firstly, a desired cutting tool is attached to the arm 7 of
the robot 4. An example of case where the electromotive saw 2, such
as the band saw 5, a wire saw, or a chain saw, is attached to the
arm 7 of the robot 4 with the attaching mechanism 3 will be
described here. On the other hand, a workpiece W to be machined is
set at a predetermined position. The workpiece W to be machined may
be placed in a state where the workpiece W to be machined has been
set on the jig J as necessary.
[0077] Furthermore, control program of the arm 7 according to a
shape of the workpiece W to be machined is input into the control
circuit 8. Thereby, machining process of the workpiece W to be
machined can be started.
[0078] In the case of performing cutoff processing of the workpiece
W to be machined with the saw 2, such as the band saw 5, it is a
preferable processing condition to incline a blade, such as the
blade 5A, with a predetermined angle toward a cutting direction in
order to reduce cutting resistance. Nevertheless, when an inclined
angle of the blade of the saw 2 is too large, the length of the
blade which contacts the workpiece W to be machined becomes long.
For example, when an inclined angle of the blade of the saw 2 is 45
degrees, the length of the blade which contacts the workpiece W to
be machined increases to about 1.4 times as long as that in the
case where the inclined angle of the blade of the saw 2 is zero
degree. As a result, it is necessary to use a blade with high
rigidity, of which upper limit of cutting length is longer.
[0079] Therefore, it is important to keep the length of an area of
the blade, which touches a workpiece W to be machined, from
becoming excessive, with suppressing cutting resistance. For that
reason, it is desirable to incline the blade of the saw 2 with an
appropriate angle determined in a range from 1 degree to 30 degrees
according to a thickness and a material of a workpiece W to be
machined, which is to be cut off.
[0080] A moving direction of a blade, such as the blade 5A, is
desirable to be downward from a viewpoint of stably fixing a
workpiece W to be machined. Specifically, when the blade of the saw
2 is moved downward, a workpiece W to be machined is pressed to the
jig J or a floor with the blade of the saw 2. Thereby, the
workpiece W to be machined can be stabilized.
[0081] In the case of inclining the blade of the saw 2, a control
position of the arm 7 is programmed so that the blade of the saw 2
contacts with a workpiece W to be machined at a predetermined
angle. Then, the control circuit 8 controls the arm 7 according to
the control program of the arm 7. Thereby, the saw 2 moves with the
arm 7. As a result, the blade of the saw 2 can cut off the
workpiece W to be machined. Specifically, the workpiece W to be
machined made of a metal, a composite material, or a honeycomb
structure can be cut off with inclining the saw 2, such as the
electromotive band saw 5, a wire saw, or a chain saw, by an angle
from 1 degree to 30 degrees in the traveling direction.
[0082] Note that, sufficient positioning accuracy may not be
acquired only by automatic control of the arm 7 by control program.
Thus, the workpiece W to be machined made of a metal, a composite
material, or a honeycomb structure can be processed along the shape
of the jig J for setting the workpiece W, by the saw 2 attached to
the arm 7 as a cutting tool, with making the guide 9 directly or
indirectly attached to the arm 7 of the robot 4 contact with the
jig J. In this case, force applied on the guide 9 from the jig J
can be measured by the pressure sensor 10 disposed in the first
joint or the like of the arm 7 of the robot 4. Then, feedback
control of the arm 7 of the robot 4 can be performed by the control
circuit 8 so that the force applied on the guide 9 from the jig J
becomes constant.
[0083] Alternatively, control to correct a position of the arm 7
can also be performed based on a reference position detected based
on an image acquired by the first visible sensor 11A attached to
the arm 7 of the robot 4.
[0084] By such technique for improving positioning accuracy, even a
machined product whose tolerance is from .+-.0.1 mm to .+-.1.0 mm
can be manufactured. Thus, even an aircraft part to which design
requirements are strict can be manufactured by machining process
using the machining apparatus 1.
[0085] When cutoff processing of the workpiece W to be machined
with the saw 2 is completed, machining process using another tool,
such as an end mill, a chamfering tool, and/or a burring tool, may
also be performed as necessary. As a matter of course, machining
process using other tools may also be performed before cutoff
processing of the workpiece W to be machined with the saw 2.
Furthermore, cutoff processing of the workpiece W to be machined
may also be performed with another saw 2 as another process.
[0086] When machining of the workpiece W to be machined is
performed using plural tools including the saw 2, the workpiece W
to be machined can be continuously processed by attaching the tools
to the arms 7 of the plural robots 4 or the plural arms 7 of the
single robot 4 respectively. Alternatively, the robot 4 may have an
ATC (automatic tool changer) so that a tool attached to the arm 7
can be automatically exchanged. Furthermore, in the case that an
exchange frequency of tool is low, attaching mechanisms for
attaching the tools to the arm 7 respectively may be prepared so
that a worker can manually exchange a tool attached to the arm 7 as
described above.
[0087] Thus, machining including cutoff of a metal, a composite
material, or a honeycomb structure can be performed using one tool
or a plurality of tools including the saw 2, such as the band saw
5, a wire saw, or a chain saw. Thereby, a desired machined product
can be manufactured.
[0088] Thus, the machining apparatus 1 as described above is
configured by attaching the electromotive saw 2, such as the band
saw 5, a wire saw, or a chain saw, to the arm 7 of the robot 4,
such as a multijoint robot, with the attaching mechanism 3.
Further, the machining method as described above is to manufacture
a machined product by processing a metal, a composite material, or
a honeycomb structure with a cutting tool attached to the arm 7 of
the robot 4, such as a multijoint robot.
(Effect)
[0089] Accordingly, the machining apparatus 1 and the machining
method allow machining of a workpiece W to be machined without
using a large scale and expensive column type machine tool. In
addition, outline trimming processing, chamfer processing, outline
finish processing and the like of a workpiece W to be machined,
which have been manually performed by a worker because of being
unable to use an expensive machine tool, can be automated. That is,
machining of a workpiece W to be machined can be automated without
using a large scale and expensive column type machine tool.
Thereby, manufacturing costs of a machined product can be
dramatically reduced.
[0090] Furthermore, high precision machining process which has
conventionally been considered to be difficult without a machine
tool can be performed using the robot 4, such as a multijoint
robot, by copying processing using the jig J or positional
correction of the arm 7 using the visible sensor 11. Thereby, it
becomes possible to process a large sized composite material panel
or a honeycomb core, typical as an aircraft part for which it is
desired to reduce manufacturing costs, at low cost with satisfying
design specification. For example, a machined product having a
tolerance from .+-.0.1 mm to .+-.1.0 mm can be manufactured by
copying processing with feedback control using the guide 9
contacting with the jig J and the pressure sensor 10.
[0091] While certain implementations have been described, these
implementations have been presented by way of example only, and are
not intended to limit the scope of the invention. Indeed, the novel
methods and systems described herein may be embodied in a variety
of other forms; furthermore, various omissions, substitutions and
changes in the form of the methods and systems described herein may
be made without departing from the spirit of the invention. The
accompanying claims and their equivalents are intended to cover
such forms or modifications as would fall within the scope and
spirit of the invention.
* * * * *