Not Applicable.
Not Applicable.
Not Applicable.
The present invention relates to machining, and more particularly to machining mill plates.
It is well known to use machine tools to cut pieces of various required shapes from larger base or stock materials.
In some cases, the pieces are cut from large (e.g., twenty feet long or longer), flat materials, such as mill plates, made of thick and heavy metal. That size makes such plates difficult to handle, and further can require a large footprint for the machine tool in a facility to provide the space needed for handling. Still further, given the complexity and size of the machine tools required to cut such materials, machine tools which have often heretofore been used in such applications provide a tool which will move in one axis of the plane of the plate (the Y-axis), in which case the mill plate itself is moved in a perpendicular axis (the X-axis).
Mill plates such as mentioned above have generally rectangular shapes with generally flat sides or edges. However, the generally flat edges are typically formed with tolerances which can result in some curvature to the “flat” edges.
Machining of such mill plates typically has been accomplished by moving the mill plate while it is being machined moved with one of its “flat” edges oriented in the one (X-axis) direction and maintained in that orientation by pressing the plate edge against one or more guides oriented in the direction of plate movement (the X-axis). However, particularly where high precision is required for the cut piece, mill plate tolerances resulting in some curvature in the edge of the large mill plate can result in undesirable curvature also in the cut piece, as illustrated in
In the prior art method illustrated in
A suitable cutting tool 30 is supported by a machine tool (not shown in
Adjacent the area of the cutting tool 30 are a plurality of vertical datum rollers 34 (pivotable about vertical axes) arranged in a vertical plane substantially perpendicular to the horizontal plane/axes of the entry conveyor rollers 28. The vertical datum rollers 34 define a base position for the side of the mill plate 20 in the area of the cutting tool 30.
On the conveyor side opposite the vertical datum rollers 34 is a pusher 40 having a roller 44 (rotatable about a vertical axis) which is biased (e.g., by a piston 46) to engaging the other side or edge 48 of the mill plate 20. The pusher 40 pushes the mill plate 20 into engagement with the vertical datum rollers 34 on the opposite side of the conveyor 24. The mill plate 20 is thus essentially oriented so that the longitudinal direction of the mill plate 20 is considered to be the direction of the edge 50 of the mill plate 20 located at the vertical datum rollers 34.
Cutting of a rectangular cut piece 60 (see
When the next corner of the piece 60 is reached, the conveyor 24 stops and holds the mill plate 20 in position while the cutting tool 30 is moved laterally across the mill plate 20 (in the direction of arrow 64,
The conveyor 24 then moves the mill plate 20 horizontally in a reverse direction (arrow 66,
Finally, when the fourth corner of the rectangular piece 60 is reached, the conveyor 24 again stops and holds the mill plate 20 in position while the cutting tool 30 is moved laterally across the mill plate 20 (in the direction of arrow 68,
It should be appreciated that two of the sides 60a and 60c will be essentially of the same orientation/shape as the longitudinally aligned edge 50 of the mill plate 20. Thus, if the edge 50 is not precisely linear (e.g., due to tolerances or damage), then the sides 60a and 60c will be similarly and undesirably cut in a non-linear fashion.
a-2e illustrate a second prior art method of cutting large mill plates 20, wherein elements identical to those illustrated in
With this second prior art method, the mill plate 20 is oriented during movement by having edge 50 pressed toward vertical datum rollers 34′ which are positioned over a longer distance (e.g., along the entire length of the conveyor 20′) than described above in connection with
It should be appreciated that if the edge 50 is not precisely linear (e.g., due to tolerances or damage), two of the sides 60a′ and 60c′ of the cut piece 60′ (which in the example is intended to be rectangular) will be not be linear due to the twisting of the mill plate 20 during cutting of those sides with the second prior art method as well.
The present invention is intended to overcome one or more of these problems.
The present invention relates to a cutting tool and method whereby a mill plate can be precisely cut notwithstanding imperfections in the sides or edges of the mill plate.
In one aspect of the present invention, a cutting device for a mill plate is provided, including a cutting tool supported for movement in a Y-direction of an X-Y-Z orthogonal coordinate system, and a conveyor adapted to convey a supported mill plate in the X-direction. The cutting tool cuts in the Z-direction through a mill plate lying generally in an X-Y plane with a thickness in the Z-direction. A measuring device at a first portion of the conveyor is movable in the X-direction along one side of a supported mill plate to map the X-axis and Y-axis positions of the supported mill plate one side. A plurality of fixed guide rollers are along the one side of a second portion of the conveyor adjacent the cutting tool, with the rollers rotatable about axes oriented in the Z-direction wherein the axes lie in an X-Z plane. At least two positioning guides are adjacent the conveyor one side on opposite sides of the cutting tool in the X-direction, where the positioning guides adjust the rollers in the Y-direction to follow the mapped Y-axis position of the mill plate one side at the X-axis position of the mill plate one side aligned with the positioning guide as the mill plate is conveyed in the X-direction. At least two clamps on the side opposite the mill plate one side are adapted to push the mill plate opposite side in the Y-direction to maintain the mill plate one side in engagement with the positioning rollers.
In one form of this aspect of the present invention, the positioning guide rollers are rotatable about axes oriented in the Z-direction, and the positioning guide roller axes are selectively movable in the Y-direction.
In another form of this aspect of the present invention, the conveyor is adapted to control the position of the mill plate in the X-direction, and each positioning guide is selectively adjustable to position its roller in the mapped Y-axis position corresponding to the X-axis position of the mill plate one side engaging the positioning guide.
In another aspect of the present invention, a cutting device for a mill plate is provided including a cutting tool supported for movement in a Y-direction of an X-Y-Z orthogonal coordinate system, and a conveyor adapted to convey a supported mill plate in the X-direction. The cutting tool cuts in the Z-direction through a mill plate lying generally in an X-Y plane with a thickness in the Z-direction. A measuring device at a first portion of the conveyor is movable in the X-direction along one side of a supported mill plate to map the X-axis and Y-axis positions of the supported mill plate one side. At least two positioning guides are adjacent the conveyor one side on opposite sides of the cutting tool in the X-direction, where the positioning guides are adjusted in the Y-direction to follow the mapped Y-axis position of the mill plate one side at the X-axis position of the mill plate one side aligned with the positioning guide as the mill plate is conveyed in the X-direction. A clamp on the side opposite the mill plate one side is adapted to push the mill plate opposite side in the Y-direction to maintain the mill plate one side in engagement with the positioning guides.
In one form of this aspect of the present invention, the positioning guides include rollers rotatable about axes oriented in the Z-direction, and the positioning guide roller axes are selectively movable in the Y-direction.
In another form of this aspect of the present invention, a plurality of fixed guide rollers is adjacent the one side of the mill plate on the conveyor, with the plurality of fixed guide rollers being rotatable about axes oriented in the Z-direction wherein the axes lie in a X-Z plane.
In still another form of this aspect of the present invention, the conveyor is adapted to control the position of the mill plate in the X-direction, and each positioning guide is selectively adjustable to position its roller in the mapped Y-axis position corresponding to the X-axis position of the mill plate one side engaging the positioning guide.
In still another aspect of the invention, a method of cutting a mill plate is provided, including the steps of (a) locating a mill plate on a conveyor with the mill plate substantially lying in an X-Y plane with a thickness in the Z-direction of an X-Y-Z orthogonal coordinate system, (b) mapping the X-axis and Y-axis positions of one side of a mill plate extending in generally the X-direction, (c) conveying the mill plate in the X-direction to a cutting tool supported for movement in the Y-direction and generally cutting in the Z-direction, (d) moving the mill plate in the X-direction and the cutting tool in the Y-direction and Z-direction while selectively cutting the mill plate, and (e) during the moving step, biasing the mill plate one side in the Y-direction against positioning guides spaced generally in the X-direction along the mill plate one side, wherein the positioning guides are adjusted in the Y-direction in accordance with mapped variations in the Y-axis positions at the X-axis positions of the mill plate one side aligned with the positioning guides to prevent twisting of the mill plate during moving of the mill plate in the X-direction.
In one form of this aspect of the invention, the mapped X-axis and Y-axis positions of the mill plate one side are stored, and each positioning guide is adjusted to match the Y-axis positions of the mill plate one side with the associated X-axis positions of the mill plate aligned in the X-direction with the aligned positioning guide.
In still another form of this aspect of the invention, the positioning guides are positioned on opposite sides in the X-direction of the cutting tool, and the biasing is accomplished by pushing the mill plate side opposite the one mill plate side toward the positioning guides.
Other objects, features, and advantages of the invention will become apparent from a review of the entire specification, including the appended claims and drawings.
a-1e illustrate the steps of a first Prior Art method used to cut a rectangular piece from a mill plate, where:
a shows the mill plate to be cut with a tool at the initial cutting position,
b shows the mill plate as moved to cut a first side of the rectangular piece,
c shows the mill plate as the tool is moved to cut a second side of the rectangular piece,
d shows the mill plate as moved to cut a third side of the rectangular piece, and
e shows the mill plate as the tool is moved to cut the fourth, final side of the rectangular piece;
a-2e illustrate the steps of a second Prior Art method used to cut a rectangular piece from a mill plate, where:
a shows the mill plate to be cut with a tool at the initial cutting position,
b shows the mill plate as moved to cut a first side of the rectangular piece,
c shows the mill plate as the tool is moved to cut a second side of the rectangular piece,
d shows the mill plate as moved to cut a third side of the rectangular piece; and
e shows the mill plate as the tool is moved to cut the fourth, final side of the rectangular piece;
a-3j illustrate the steps used to cut a rectangular piece from a mill plate according to the present invention, where:
a shows the mill plate prior to being loaded onto an entry conveyor,
b shows the mill plate as moved onto the entry conveyor,
c shows the mill plate as it has one side mapped,
d shows the mill plate as it is moved to a cutting tool for cutting a piece from the plate,
e shows the mill plate positioned relative to a cutting tool for initiation of cutting,
f shows positioning guides being engaged with the mapped side of the mill plate to initial cutting,
g shows the mill plate as moved to cut a first side of the rectangular piece with the positioning guides adjusted to follow the mapped side of the mill plate as it moves past the guides,
h shows the mill plate as the tool is moved to cut a second side of the rectangular piece,
i shows the mill plate as moved to cut a third side of the rectangular piece with the positioning guides adjusted to follow the mapped side of the mill plate as it moves past the guides, and
j shows the mill plate as the tool is moved to cut the fourth, final side of the rectangular piece;
The present invention is illustrated in
Referring first to the inventive method,
With this novel method, the mill plate 20 is first located on the entry conveyor 24″ with at least two locations (e.g., corners at opposite ends) along the longitudinal edge 50 at known, base locations. For example, base plates 70 may be located at opposite ends of the entry conveyor 24″, with the two plates 70 aligned in the X-direction (i.e., along a horizontal line which is perpendicular to the axes of the fixed datum rollers 28). The base plates 70 may also be datum rollers. The mill plate 20 may be loaded onto the entry conveyor 24″ and then pushed horizontally in the Y-direction (i.e., the direction of the datum roller axes as illustrated by the arrow 72 in
With the mill plate 20 in this known position (see
The mill plate 20 is then moved in the X-direction (see arrow 86 in
The rollers 92 are selectively moved in the Y-direction during operation. Specifically, as the mill plate 20 is moved over the entry conveyor 24″ in the X-direction, the mapped plate edge 50 also moves past the positioning guides 90. Using the stored map of the edge 50 in the X-Y plane, each of the guides 90 are controlled so that their rollers 92 are extended out to the mapped Y-position of the plate edge 50 associated with the X-position of the plate edge 50 aligned with the guide 90.
On the opposite side 48 of the plate 20, biasing clamps or pushers 94 are provided which push against that mill plate side 48 in the Y-direction toward the positioning guides 90. These clamps 94 may advantageously include rollers 96 rotatable about vertical (Z) axes to allow the mill plate 20 to move past them in the X-direction without binding, and are suitably biased with a sufficient force (e.g., by a hydraulic piston configuration) to ensure that the mapped edge 50 of the plate 20 will be kept in contact with the positioning guide rollers 92 on the side opposite the biasing clamps 94.
It should thus be appreciated that, as shown in
Cutting of a rectangular cut piece 60″ (see
The mill plate 20 is first positioned so that the cutting tool 30 is positioned over one corner of the piece to be cut (
When the next corner of the piece 60″ is reached, the conveyor 24 stops and holds the mill plate 20 in position while the cutting tool 30 is moved laterally across the mill plate 20 (in the direction of arrow 64″,
The conveyor 24 then moves the mill plate 20 horizontally in a reverse X-direction (arrow 66″,
Finally, after the fourth corner is reached at the end of the step illustrated in
It should be appreciated that whereas two of the sides 60a, 60a′ and 60c, 60c′ could be neither precisely linear nor at right angles to sides 60b, 60b; and 60d, 60d′ (e.g., if tolerances or damage result in the plate side 50 not being linear) when the piece 60, 60′ is cut according to one of the described prior art procedures, the sides 60a″-60d″ of a rectangular piece 60″ cut according to the present invention would all be straight and at right angles to each other.
Of course, it should be appreciated that while the above described example of cutting a rectangular piece has been used for illustrative purposes, the present invention can be used to ensure that pieces are precisely cut to different desired shapes as well.
Specifically, the machine tool 100 of
On the exit side of the machine tool 100, a dump table 130 is provided to facilitate handling of scrap and cut pieces after cutting. As is known, the dump table 130 may be moved up and down and tilted to facilitate dumping of scrap into a scrap hopper 134 disposed beneath the dump table 130. The scrap hopper 134 may be rolled from beneath the dump table 130 to allow it to be emptied. An exit conveyor 140 with suitable rollers 142 (not shown in
Wheels or rollers 150 (see
It should be appreciated that machine tools of a variety of designs, and having a variety of features, can be used with the present invention including, for example, High Speed Plate Systems (e.g., the High Speed FDB-2500) available from Peddinghaus Corporation (300 North Washington Avenue, Bradley, Ill. 60915) and its related companies.
Operation of a machine tool 100 such as described above with the present invention is illustrated in
As illustrated in
While held in that position, the mill plate longitudinal edge 50 is mapped by movement of the mapping device 80 which moves along the length of the side (arrow 80) and follows and measures the Y-direction position of the side 50 at selected intervals (e.g., each inch). The mapped positions of the longitudinal side 50 are stored in the control 156.
While mapping of the mill plate longitudinal edge 50 is being done, the machine tool 100 may also be prepared for the desired cutting of the mill plate 20. For example, the rotary tool changer 116 may be moved (see arrow 160 in
The mill plate 20 is then advanced into the machine tool 100 along the entry conveyor 24 (see arrow 86 in
At that point, operation continues as generally described herein in connection with
That is, the rollers 92 of the positioning guides 90 are selectively moved in the Y-direction as the mill plate 20 is moved over the entry conveyor 24″ in the X-direction. Using the stored map of the edge 50 in the X-Y plane, each of the guides 90 are controlled so that their rollers 92 are extended out to the mapped Y-position of the plate edge 50 associated with the X-position of the plate edge 50 aligned with the guide 90.
On the opposite side 48 of the plate 20, biasing clamps 94 push against that mill plate side 48 in the Y-direction toward the positioning guides 90 to ensure that the mapped edge 50 of the plate 20 will be kept in contact with the positioning guide rollers 92 on the side opposite the biasing clamps 94. Therefore, during cutting of the mill plate 20 by the tool 30 in the tool spindle 108, the plate 20 will be moved only in the X-direction, without any twisting occurring around the Z-axis.
To cut a rectangular cut piece 60″ (see
When the next corner of the piece 60″ is reached, the mill plate 20 is held in a fixed position while the tool spindle 108 and tool 30 is moved laterally across the mill plate 20 (in the direction of arrow 64″,
The conveyor 24 then moves the mill plate 20 horizontally in a reverse X-direction (arrow 66″,
After the fourth corner is reached at the end of the step illustrated in
After the piece 60″ is fully cut, the mill plate 20 may be suitably advanced (in the direction of arrow 176,
It should be appreciated that the present invention will allow precise cutting of a piece from a mill plate, even where the mill plate has an irregular side. This will enable cut pieces to meet the smallest of tolerances despite such plate irregularities.