CN101468471B - Cutting machine and sheet feeding cutting method - Google Patents

Abstract

When cutting a sheet with a cutting machine that can perform sheet feed cutting, even when cutting long parts, the waiting time of cutting units such as cutting blades can be shortened as much as possible to improve cutting efficiency. After the previous part is cut by sheet feeding and cutting, when the sheet feeding and cutting of the next part is performed subsequently, the judging unit judges the cutting line to be cut by the cutter according to the cutting data and before cutting the next part. Whether the object part enters the cutting area, when the judging result of the judging unit is that the object part on the cutting line to be cut by the cutting knife has entered the cutting area during cutting, the sheet material is carried out next to the previous part. For cutting, when it is judged that the target part on the cutting line to be cut by the cutting knife is a part that does not enter the cutting area during cutting, the calculation unit calculates the cutting waiting time for carrying in the sheet without cutting, and the cutting time. The cutting waiting position of the head, so that during the sheet feeding and cutting, the target part on the cutting line to be cut by the cutting knife enters the cutting area, and the cutting waiting position obtained by the arithmetic unit is determined by the cutting waiting position during the cutting waiting period. The control unit carries in the sheet without cutting it.

Description

Cutter and Sheet Feed Cutting Method

technical field

The present invention relates to a cutting machine for cutting sheets of cloth, leather, etc. A cutting machine for cutting, and a sheet-feed cutting method.

Background technique

As a sheet cutting method of an existing cutting machine that cuts a sheet while moving on a cutting table, for example, Patent Document 1 discloses a sheet feeding and cutting method, which is a method for cutting a sheet along a predetermined The method of cutting along the path constitutes a processing window with a preset length equal to or less than the length of the processing area in the advancing direction of the sheet, and by moving the processing window while the sheet is advancing, the cutting knife, etc. are processed. The tool moves in two directions (X-axis direction·Y-axis direction) within the determined processing window, and cuts the sheet while moving through each path within the processing window.

In the sheet feeding and cutting method as described above, since the sheet is advanced while the processing window is also moved, the sheet is cut by a processing tool such as a cutting knife along the path in the processing window. The cutting processing range is limited to the range of a narrow processing window in the sheet feeding direction (X-axis direction).

Therefore, if the cutting member in the processing area is so long in the sheet feeding direction (X-axis direction) that it overflows the processing window, it must enter the processing window multiple times for cutting.

Cutting a single part intermittently in such a narrow space is not only time-consuming and labor-intensive, but it is also difficult to realize the connection points neatly, and cutting residues are likely to be generated, which may cause problems in product value.

Patent Document 1 Japanese PCT Publication No. 8-511480

Contents of the invention

The present invention has been proposed in view of the above-mentioned problems, and its object is to shorten the processing tools such as cutters ( Cutting unit) waiting time, improve cutting efficiency, prevent cutting residues at the same time, can improve commodity value.

In order to achieve the above object, the cutting machine of the present invention is a cutting machine capable of feeding and cutting sheets. The conveying unit on the cutting table moves the cutting head along the cutting line while the conveying unit carries the sheet in, and cuts the parts from the sheet. After the previous part is cut, when the next part is fed and cut, before the next part is cut, it is judged according to the cutting data whether the object part on the cutting line to be cut by the cutting knife enters the cutting area; the computing unit , when the judging unit judges that the target part on the cutting line to be cut by the cutting knife has entered the cutting area during cutting, the sheet feeding and cutting is performed next to the previous part, and when it is judged that the cutting knife needs to When the target part on the cutting line for cutting is a part that does not enter the cutting area during cutting, the calculation unit calculates the cutting waiting time for carrying in the sheet without cutting and the cutting waiting position of the cutting head so that In sheet feed cutting, the target portion on the cutting line to be cut by the cutter enters the cutting area; the cutting control unit, at the waiting position for cutting obtained by the calculation unit, performs cutting without cutting during the waiting period. Loading of sheets.

In the cutting machine of the present invention, it is characterized in that: during the waiting time for cutting, the above-mentioned cutting control unit increases the speed at which the sheet is carried in by the conveying unit, and at the same time, the calculating unit recalculates the waiting time for cutting when the speed at which the sheet is carried in increases, or , the cutting waiting position calculated by the computing unit is any position between the cutting end position of the previous part and the cutting start point of the next part, or after the cutting of the next part starts, in the part cutting in the cutting area, use The trimming knife is raised into position on the sheet.

Furthermore, the cutting machine of the present invention is characterized in that the judging unit searches for the cutting direction from the sheet carrying in direction on the side closer to the sheet carrying in than the cutting starting point in the direction of cutting on the cutting line from the cutting start point of the part. When one or more turning points are found, calculate the time T1 required for cutting from the cutting start point to the turning point and the time required before the turning point enters the cutting area based on the cutting data. T2, for all the searched return points, when the time T1 required for cutting from the cutting start point to the return point is longer than the time T2 required before the return point enters the clipping area, follow the previous part and proceed to the next part When it is judged that there is a turning point for which the time T1 required for cutting from the cutting start point to the turning point is not longer than the time T2 required until the turning point enters the cutting area, the above-mentioned calculation unit performs the target turning point , the calculation makes the cutting waiting time longer than the time T2 required before the turning point enters the cutting area from the cutting start point to the turning point required time T1, and at the same time, the cutting waiting position of the cutting head is obtained.

The sheet feeding and cutting method of the present invention is a cutting method performed by a cutting machine capable of sheet feeding and cutting. The sheet is carried into the conveying unit on the cutting table, while the conveying unit is carrying the sheet in, the cutting head is moved along the cutting line, and the parts are cut from the sheet. After cutting the previous part, when the next part is fed and cut, before the next part is cut, it is judged according to the cutting data whether the object part on the cutting line to be cut by the cutter enters the cutting area. The result of the judgment is that when it is judged that the object part on the cutting line to be cut by the cutter has entered the cutting area during cutting, the sheet is fed and cut next to the previous part, and when the cutting line to be cut by the cutter is judged When the target part above is a part that does not enter the cutting area during cutting, calculate the cutting waiting time for carrying in the sheet without cutting, and determine the cutting waiting position of the cutting head so that when the sheet is fed and cut, The target portion on the cutting line to be cut by the cutter enters the cutting area, and at the obtained cutting waiting position, the sheet is carried in without cutting during the cutting waiting period.

Furthermore, the sheet feeding and cutting method according to the present invention is characterized in that during the cutting waiting time, the feeding speed of the sheet by the transport unit is increased, and the cutting waiting time when the sheet feeding speed is increased is recalculated.

Because the cutting machine of the present invention is structured to have: the judging unit, after the previous part is cut by the sheet feeding and cutting, when the sheet feeding and cutting of the next part is carried out subsequently, the judging unit is based on the cutting data before cutting the next part. Judging whether the object position on the cutting line to be cut by the cutter has entered the cutting area; the calculation unit, when the judgment result of the judging unit judges that the object position on the cutting line to be cut by the cutting knife has entered in the cutting area when cutting , the sheet is fed and cut next to the previous part, and when it is judged that the target part on the cutting line to be cut by the cutting knife is a part that does not enter the cutting area during cutting, the calculation unit does not perform cutting Carry out the cutting waiting time for the sheet to be carried in accurately, and determine the cutting waiting position of the cutting head, so that in the sheet feeding and cutting, the object part on the cutting line to be cut by the cutting knife enters the cutting area; the cutting control unit, in The cutting waiting position calculated by the calculation unit can be used to carry in the sheet without cutting by the cutting control unit during the waiting period for cutting. Therefore, it is possible to provide a cutting machine that shortens the length of the sheet as much as possible even when cutting long parts. The waiting time of processing tools (cutting unit) such as cutting knives improves cutting efficiency, and at the same time prevents cutting residues, enabling cutting with high commodity value.

Moreover, during the waiting time for cutting, the cutting control unit increases the feeding speed of the sheet by the conveying unit, and the calculation unit recalculates the waiting time for cutting when the feeding speed of the sheet increases, so that the waiting time can be shortened and the cutting efficiency can be further improved. .

The clipping waiting position calculated by the arithmetic unit is any position between the clipping end position of the previous part and the clipping start point of the next part, or after the clipping of the next part starts, in the part clipping in the clipping area, make the clipping The scissors are raised to the position on the sheet, so there is an advantage that the cutting waiting time can be effectively utilized, and the cutting efficiency can be further improved.

And, in the direction of cutting on the cutting line from the cutting start point of the part, the judgment unit searches for a turning point in the cutting direction from the sheet carrying-in side to the sheet-carrying-out side on the side closer to the sheet carrying-in side than the cutting starting point, When one or more turning points are found, according to the cutting data, calculate the time T1 required for cutting from the starting point of the cutting to the turning point, and the time T2 required before the turning point enters the cropping area, for all the turned backs that are searched point, when the time T1 required for cutting from the cutting start point to the turning point is longer than the time T2 required before the turning point enters the cutting area, the sheet feeding and cutting of the next part is carried out immediately after the previous part, when judging When there is a turning point for which the time T1 required for cutting from the cutting start point to the turning point is not longer than the time T2 required until the turning point enters the trimming area, the calculation unit calculates, for the turning point that is the object, the time T1 for cutting from the cutting start point. The time T1 required to reach the turning point becomes the cutting waiting time longer than the time T2 required before the turning point enters the cutting area, and the cutting waiting position of the cutting head is obtained at the same time, so it is possible to use processing tools such as cutting knives (cutting unit) The advantage of eliminating invalid waiting time and improving cutting efficiency.

According to the sheet feeding and cutting method of the present invention, since the previous part is cut by the sheet feeding and cutting, when the next part is subsequently cut by the sheet feeding and cutting, the judging unit determines the next part according to the cutting data. Before cutting, judge whether the object part on the cutting line to be cut by the cutting knife has entered the cutting area, when the judgment result of the judging unit is to judge that the object part on the cutting line to be cut by the cutting knife has entered the cutting area when cutting , the sheet is fed and cut next to the previous part, and when the judging result of the judging unit is that the target part on the cutting line to be cut by the judging knife is a part that does not enter the cutting area during cutting, the The calculation unit calculates the cutting waiting time for carrying in the sheet without cutting and the cutting waiting position of the cutting head so that the target part on the cutting line to be cut by the cutting knife enters the cutting area during the sheet feeding and cutting, At the obtained cutting waiting position, the cutting control unit carries in the sheet without cutting during the cutting waiting period. Therefore, by using this cutting method to novelly replace the existing cutting method, it goes without saying that even in When cutting the above-mentioned long parts, it also has the advantage of shortening the waiting time of processing tools (cutting units) such as cutting knives as much as possible, improving cutting efficiency, preventing cutting residues from being produced, and improving the commodity value of the parts after cutting.

Description of drawings

Fig. 1 is a perspective view showing the appearance of the cutting machine of the present invention.

Fig. 2 is a block diagram showing a schematic electrical structure of an embodiment of the present invention.

Fig. 3 is a flow chart of the cutting operation performed by the cutting machine shown in Fig. 1 .

Fig. 4 is an explanatory view of the cutting operation performed by the cutting machine shown in Fig. 1 .

Explanation of reference signs

1. Cutting machine 2. Cutting table 4. Sheet 5. Cutting knife 9. Cutting unit 18. Cutting control unit 17. Calculation unit 20. Judgment unit C. Cutting area

Detailed ways

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a perspective view showing the appearance of a cutting machine 1, and reference numeral 1 in the drawing generally denotes the cutting machine. The cutting carriage 3 is arranged on the cutting table 2 of the cutting machine 1 .

The cutting carriage 3 can move along its length direction on the cutting table 2, that is, the conveying direction (X-axis direction) of the sheet 4, and the cutting head 6 with the cutting knife 5 moves along the width direction of the sheet 4 on the cutting carriage 3. That is, the cutting carriage 3 is movably provided in the Y-axis direction perpendicular to the conveying direction, and the cutting blade 5 constitutes a cutting unit 9 for cutting the sheet 4 .

Furthermore, the cutting blade 5 can be raised and lowered in the Z-axis direction via a lifting unit (not shown) assembled on the cutting carriage 3 .

The cutting table 2 is driven by a conveyor belt with a plurality of bristle brushes 7 on the surface, and the sheet 4 is cut by the cutting blade 5 of the cutting unit 9 sliding up and down at high speed according to the cutting data 8 shown in FIG. 3 .

An air-impermeable cover sheet 11 of polyethylene or the like drawn out from the sheet roll 10 covers the surface of the sheet 4 .

The non-breathable covering sheet 11 is also cut together with the sheet 4 by the cutting blades 5 of the cutting head 6 .

Since the air impermeability of the air-impermeable covering sheet 11 is lost by this cutting, it is covered again with a new air-impermeable covering sheet 12 after cutting.

The new air-impermeable cover sheet 12 is stretched between a sheet roll 13 provided on the cutting carriage 3 and a stand 14 provided at the front end of the cutting table 2 .

Usually, an unshown spread table is arranged on the sheet material loading side of the cutting machine 1, and the sheet 4 that should be spread by the spread machine is drawn out on the spread table, and the sheet is drawn with a desired length. 4 stacked. In addition, a pickup table (not shown in the figure) is provided on the sheet delivery side of the cutter 1, and the cut sheet 4 is carried out to the pickup table.

On this kind of cutting machine 1, cutting efficiency can be improved by carrying the sheet 4 into the cutting table 2 of the cutting machine 1 while cutting, and the parts after cutting can be used to pick up the table (in the figure) that is arranged on the upper left in the figure. not shown) was taken out.

Therefore, the longer the sheet 4 is, the more efficiently it can be spread out and cut by the cutting machine 1 .

The sheet 4 is disposed on a lower bedding sheet (not shown in the figure) having a larger area, and the lower bedding sheet is, for example, kraft paper with air holes at certain intervals.

When the spread sheet 4 is cut by the cutting machine 1 , an underlay sheet is used to prevent the bristle brush 7 forming the surface of the cutting table 2 of the cutting machine 1 from getting stuck in the sheet 4 .

The reference sign (C) in the figure represents the cutting area (C) on the cutting table 2, and the sheets 4 stacked on the spreading table by the spreading machine are carried in from the sheet material loading side of the cutting table 2 (from the right side in the figure). direction to the left), and cut in the cutting area (C).

Fig. 2 is a block diagram showing a schematic electrical structure of an embodiment of the present invention.

Cutting data 8 created by a CAD device or the like is input to the input unit 15 . The storage unit 16 stores the cropping data 8 input by the input unit 15 .

The cutting control unit 18 controls the cutting unit 9 composed of a conveying unit 19 provided on the cutting machine 1 such as a conveyor belt, and a cutting blade 5 driven up and down.

For parts cut by sheet-feed cutting in the cutting area (C) on the cutting table 2 from there, the judging unit 20 judges that during the sheet-feed cutting, the parts cut by the cutter are as described below. Whether the target part on the trimming line of the part enters the trimming area (C).

When the judging unit 20 judges that the target part on the cutting line cut by the cutting blade is a part that does not enter the cutting area (C) during the feeding and cutting of the sheet, the computing unit 17 calculates that the sheet is carried in without cutting. and determine the cutting waiting position of the cutting head 6 during the cutting waiting period, so that the cutting part on the cutting line to be cut during the feed cutting enters the cutting area (C).

The above judgment unit 20 , storage unit 16 and cutting control unit 18 are arranged in the controller 21 of the cutting machine 1 as shown in the figure.

Next, a process of cutting the sheet 4 by the cutting machine 1 configured as described above will be described.

In addition, FIG. 3 is a flowchart of the judging unit 20, and this flowchart is implemented before the cutting of each part is started.

The sheet feed cutting is started, and the sheet 4 stacked by the spreading machine is conveyed to the cutting head 6 of the cutting machine 1 while cutting.

As shown in Figure 3, judging unit 20 starts in step (S1), and in step (S2), from the cutting start point S of part P shown in Figure 4 along the direction of cutting on cutting line L, in step (S2) The cutting start point S is closer to the loading side of the sheet material 4, and the turning point Pn of the cutting direction from the loading side of the sheet material 4 to the output side of the sheet material 4 is searched for, and one or more turning point Pn (in FIG. 4 ) is identified. , part 1 and part 2 each have one turning point P1, and part 3 has three turning points P1·P2·P3), in step (S3) it is judged whether there is the turning point Pn.

When step (S3) judges that there is not one turnback point Pn on the part to be cut next time, enter step (S4), and cut by sheet material feeding intact, utilize the cutting knife 5 of cutting unit 9 along the cutting line L Sheet 4 is trimmed.

When step (S3) is judged to have 1 or more turnback points Pn, enter step (S5), according to the cutting data 8, calculate from the cutting start point S of cutting parts to the required time T1 of each turnback point Pn , and the required time T2 before each turning point Pn enters the clipping area (C).

Enter step (S6) then, for each turnback point Pn, compare the time T1 required for cutting to each turnback point Pn from the cutting start point S, and the required time T2 before each turnback point Pn enters the cutting area (C) , if the time T1 required for cutting from the cutting start point S to the return point Pn is longer than the time T2 required until the return point Pn enters the cutting area (C) for all the return points Pn, during sheet feeding and cutting When the turning point Pn is cut, the turning point Pn has already entered the cutting area (C), and the step (S4) is entered, and the sheet feeding and cutting is performed next to the previous part.

On the contrary, when there is a turning point Pn for which the time T1 required for cutting from the cutting start point S to the turning point Pn is not longer than the time T2 required until each turning point Pn enters the cutting area (C), even if the cutting is performed as it is, Material feeding and cutting, because the part to be cut does not enter the cutting area (C), it cannot be cut.

Enter step (S7) now, calculate the cutting waiting time for carrying out the sheet material 4 without cutting, and determine the cutting waiting position of the cutting head 6 at the same time, so that the time required for cutting to the turning point Pn is cut from the cutting start point S T1 becomes longer than the time T2 required until each turnback point Pn enters the trimming area (C). It goes without saying that the cutting waiting position can be any position such as the cutting start point S of the part to be cut next time after the part was cut last time. The position above the sheet material 4 is used as a waiting position for the cutting head 6 .

In step (S8), during the waiting period for cutting calculated by the above step (S7), the cutting knife 5 does not cut, the cutting head 6 is placed at the cutting waiting position, and the sheet is carried into the cutting area (C) of the cutting machine 1 superior.

In this way, once the waiting time for cutting has elapsed, sheet feeding and cutting are started again.

During the cutting waiting period, if the conveying speed (for example, 6 to 10 m/min) of the sheet by the conveying unit 19 is several times that of the normal cutting (for example, 3 to 5 m/min), the cutting waiting time can be shortened. . At this time, the waiting time for cropping is calculated again by the calculating unit 17 .

In FIG. 4, the sheet feed cutting of the present invention is illustrated.

After part 1 and part 2 are cut by sheet feed cutting, part 3 is then cut.

First, a search is made by the judging unit 20 as to whether there is a return point on the component 3 . In the case of this component 3, it is recognized that there are three turning points P1·P2·P3. Then, for each turning point, the time T1 required for cutting from the cutting start point S to each turning point Pn and the time T2 required for each turning point Pn to enter the cutting area (C) are calculated based on the cutting data 8 .

Then, for each turning point Pn, the time T1 required for cutting from the cutting start point S to each turning point Pn is compared with the time T2 required until each turning point Pn enters the cutting area (C). Judging the comparison result, for example, the turning point P2 is a turning point where the time T1 required for cutting from the cutting start point S to the turning point Pn is not longer than the time T2 required before each turning point Pn enters the cutting area (C). At this time, the calculation unit obtains the cutting waiting time for carrying in the sheet 4 without cutting for the turning point P2, and the cutting waiting position of the cutting head 6, so that it is necessary to cut from the cutting start point S to the turning point P2. The time T1 becomes longer than the time T2 required until the turn-back point P2 enters the cropping area (C).

It goes without saying that the cutting waiting position may be the cutting start point S in the part 3, but as long as the cutting knife 5 is raised and pulled out from the sheet 4 between the cutting start point S and the turning point P2 If the position μ is used as the waiting position of the cutting head 6, the cutting waiting time can be further shortened, and the cutting efficiency can be further improved.

In addition, when shortening the waiting time for cutting, during the period from the end of the cutting of the previous part to the start of cutting of the next part to be cut, once the cutting knife 5 is raised from the cutting end part of the part, and moves to the cutting start position of the part , by adding the falling time of the cutting knife at the cutting start position to the time T1 required for cutting to each turnback point from the cutting start point S of the next cutting part, the cutting waiting time can be further shortened.

Moreover, in the above-mentioned embodiment, although the cutting unit 9 is formed by the cutting blade 5 sliding up and down at high speed, it is not limited thereto, and it goes without saying that the cutting blade may also be a circular blade, or form a cutting unit 9 by a laser beam or a jet stream. Unit 9.

Claims (6)

1. A cutting machine, which is a cutting machine capable of feeding and cutting sheets, is provided with a cutting head that is equipped with a cutting knife and moves freely on a cutting table, and is provided with a device that carries a sheet to be cut onto the cutting table. The conveying unit, while the sheet is carried in by the conveying unit, the cutting head is moved along the cutting line, and the parts are cut from the sheet, and it is characterized in that it includes: The judging unit is configured to judge, according to the cutting data, the position on the cutting line to be cut by the cutter according to the cutting data when the next part is subsequently cut by the sheet feeding and cutting after the previous part is cut by the sheet feeding and cutting. Whether the object part enters the clipping area; The calculation unit, when the judgment result of the judging unit is that it is judged that the target part on the cutting line to be cut by the cutting knife has entered the cutting area during cutting, the sheet is fed and cut next to the previous part, and the When it is judged that the target part on the cutting line to be cut by the cutter has a part that does not enter the cutting area during cutting, the calculation unit calculates the cutting waiting time for carrying in the sheet without cutting, and determines the cutting head. The waiting position for cutting, so that in the sheet feed cutting, the object part on the cutting line to be cut by the cutting knife enters the cutting area; The trimming control unit carries in the sheet without trimming at the trimming waiting position obtained by the calculating unit during the trimming waiting period. 2. The cutting machine according to claim 1, wherein the cutting control unit increases the speed at which the sheet is carried in by the conveying unit during the waiting time for cutting, and the calculation unit recalculates the time when the speed at which the sheet is carried in is increased. Clipping wait time. 3. The cutting machine according to claim 1 or 2, characterized in that: the waiting position for cutting determined by the computing unit is any position between the cutting end position of the previous part and the starting point of cutting the next part, or After the cutting of the next part starts, the cutting blade is raised to a position on the sheet during part cutting in the cutting area. 4. The cutting machine according to claim 1, wherein: along the direction of cutting on the cutting line from the cutting start point of the part, the judgment unit searches for the cutting direction on the side closer to the sheet loading side than the cutting start point. When one or more turning points are found at the turning point from the sheet input side to the sheet output side, the time T1 required for cutting from the cutting start point to the turning point and the turning point are calculated based on the cutting data. The required time T2 before entering the cropping area, for all the searched turning points, when the time T1 required for cutting from the cutting start point to the turning point is longer than the required time T2 before the turning point enters the cutting area, Next to the previous part, the sheet feeding and cutting of the next part is performed, and when it is judged that there is a turning point where the time T1 required for cutting from the cutting start point to the turning point is not longer than the time T2 required until the turning point enters the cutting area In this case, the above operation means calculates, with respect to the turning point as an object, the cutting waiting time such that the time T1 required for cutting from the cutting start point to the turning point becomes longer than the time T2 required until the turning point enters the cutting area, and determines The cropping wait position of the cropping head. 5. A sheet-feed cutting method, which is a cutting method implemented by a cutting machine capable of sheet-feed cutting, the cutting machine being provided with a cutting head mounted with a cutting knife and freely movable on a cutting table, A conveying unit is provided to carry the sheet to be cut into the cutting table, and while the conveying unit carries the sheet in, the cutting head is moved along the cutting line to cut parts from the sheet, and it is characterized in that: After the previous part is cut by the sheet feed cutting, when the next part is subsequently cut by the sheet feed, before the next part is cut, it is judged based on the cutting data whether the target part on the cutting line to be cut by the cutter is Entering the cutting area, when the judgment result is that the object part on the cutting line to be cut by the cutting knife has entered the cutting area during cutting, the sheet feed cutting is performed next to the previous part, and the When it is judged that the target portion on the cutting line to be cut by the cutter has a portion that does not enter the cutting area during cutting, calculate the cutting waiting time for carrying in the sheet without cutting, and determine the cutting waiting time of the cutting head position so that during sheet feeding and cutting, the target portion on the cutting line to be cut by the cutter enters the cutting area, and at the obtained cutting waiting position, the sheet is cut without cutting during the cutting waiting period. move in. 6. The sheet feeding and cutting method according to claim 5, wherein during the waiting time for cutting, the speed at which the sheet is brought in by the transport unit is increased, and the waiting time for cutting when the speed at which the sheet is brought in is increased is recalculated.

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