TWI836586B - An apparatus and a method for producing side gusseted bags with valve and side gusseted bags with valve - Google Patents

Abstract

The invention discloses a side gusseted bags with a valve and an apparatus and method of producing it. The apparatus has a web puller unit (A), a first cutting unit (B), a first folding unit (C), a first sealing unit (D), a conveying unit (E), a second cutting unit (F) having a first and second cutting blade (15, 15A), an opening and inward folding unit (G), a pressing unit (H), an eco cutting unit (I), a second folding unit (J), a second sealing unit (K), and a stacking unit (L). An L-shaped cut is made on the second end of the fabric at second cutting unit (F) with first and second cutting blades (15, 15A) that moves in the traverse and transpose direction, whereafter at opening and inward folding unit (G), the second end is opened by a suction means such that a space is created for tool insertion, where the second end of the cut piece of the gusset fabric is folded and sealed to form a valve (9).

Description

Apparatus and method for producing side bags with valves and side bags with valves

The present invention relates to an apparatus and method for manufacturing a side bag with a valve. More specifically, the present invention relates to high-speed automated production of a side bag with a valve.

Bags or sacks have been used to package/store/transport materials such as grain, flour and various industrial materials. These sacks can take on different shapes such as pillow and box shapes. A pillow shape is usually created by making the bottom with a seam. A box shape is created by folding the bottom and joining the bottom into a block form. It will be appreciated by those of ordinary skill that a box shape optimizes the use of the material surface due to its brick shape, facilitates stacking and provides improved utilization of volume.

However, the main disadvantage of box bags is that they involve complex mechanisms that are difficult to manufacture and very expensive. Therefore, the demand for pillow bags with some of the characteristics of box bags evolved. These box bag features can be incorporated into pillow bags by manufacturing the sides in the pillow bag. These multi-layer bags form flat sides when filled, which allows the bags to be stably stacked on a loading pallet and therefore also requires less space. These bags involve less complex mechanisms when manufactured and are cost-effective.

In the process of woven fabrics for making sacks for stacking applications, valves for quick filling of materials such as cement or any other kind of powdered or granular raw materials such as sand, grains, etc. are usually formed into the sacks. Knownly, such valves are formed manually by opening the sack at one of its corners and forming a filling opening. Such known methods of making valves or creases at one end of tubular sacks are time consuming, especially as the demand for the production of bags/sacks with valves increases. Therefore, there is a need for an automated method of making valves in such bags.

One such side pocket is disclosed in US Pat. No. 1,01796B2 ('8796). Patent ('8796) discloses a bag with front and back panels having upright longitudinally extending side edges and laterally extending upper and lower edges. The first and second side panels each have transversely extending upper and lower edges and an upright longitudinal outer edge connected to the longitudinal edge of the panel. A strip of reclosable fasteners extends continuously and laterally along the first side panel and inwardly along each panel from the first side panel along a portion of the lateral width of the panel. Therefore, the opening of the fasteners and the outward folding of the first side panel form a first-flow outlet on the bag. A single, generally rectangular floor panel is heat welded at its outer edge to the lower edge of the panel and side panels. However, the above bag disclosed in the patent ('8796) does not have a valve for filling material or the above patent does not disclose anything about the equipment for making the bag. In this condition, a separate closing unit is required for closing the bag after filling. Therefore, for faster filling rates, valves are required in side bags.

However, a side polymer bag with a filling valve and a method of making the same are known, comprising a tubular body with opposite sides defining front and rear panels and a filling valve formed by folding the front and rear panels, wherein the edge portions are interconnected inwardly into the bag at one corner of the bag to form a filling panel, and then the top edges of the front and rear panels are sealed simultaneously, wherein the top edges of the filling panel form a filling tube and valve that self-seals under the force of the material as it rises in the bag. One such bag is disclosed in patent US 6997858B1 ('858). Patent ('858) Further discloses a side plastic bag with a valve, which is heat sealed at the ends, wherein the side bag with a valve is manufactured. Heat sealing methods for sealing bag ends can provide good sealing joints for plastic bags, but in case of woven fabrics, it will not provide a strong sealing joint or a special type of sealing joint is required to seal edged bags. However, the patent ('858) does not disclose any equipment for making edged plastic bags and involves a complicated method of manually folding the plastic bag along the folding line to make a bag, which is time consuming and reduces the production rate. It is further mentioned that to date, there is no automated system or machine for making such bags.

Another patent, CA627439 ('439), discloses a bag with a side and a valve. The patent ('439) discloses a multi-walled valve bag that only has sides at one end, so the side walls of the bag will not bulge enough when filled with material because the two side walls of the bag are not identical in construction. The patent ('439) discloses the concept of a saddlebag with a valve but does not address an automated process for manufacturing the saddlebag.

However, the above patent discloses a non-woven bag with a valve or paper, or the same type of bag with a valve. The prior art does not disclose anything regarding automated methods and equipment for producing valved bags for woven packaging bag formation.

Therefore, there is a need for an automated system or apparatus and method for producing valved side bags that can be economically manufactured at high production rates.

The main purpose of the present invention is to provide an automated method and equipment for manufacturing side bags with valves.

Another object of the invention is to provide a bag having side bags with valves sealed at the ends.

A further object of the present invention is to provide an automated bag making system operating at high speed. Equipment for manufacturing side bags with valves on the manufacturing line.

According to the present invention, a side woven bag with a filling valve and a method for manufacturing the same on an automated machine are provided. The side woven material comprises a multi-layer structure that can be produced by a loom by inserting a side tool and thereby winding it on a roll. This roll is conveyed to the bag making machine for producing bags. However, this process of making the side woven material roll can be online with the bag making machine in order to reduce the downtime of the roll conveyance.

In addition to this, this fabric with sides can also be obtained on the bag making machine from a flat fabric with a single flat end, thereby forming a tube structure and at the same time installing the side tools just after the unfolding station. The arm/tool is fabricated to insert into the tubular fabric from the side such that it folds the tubular fabric inwardly, making the construction into multiple layers. In Figure 1A there is shown a method of making sides from an edgeless tubular fabric (6), wherein the edgeless tubular fabric (6) unrolls itself and passes through an insertion member (18) which is inserted or provided to the tubular fabric Lateral pressure creates an inwardly folded multi-layered fabric called a side fabric. The fabric edging fabric thus obtained can be cut to a predetermined length by the first cutting unit (B) to form a cutting piece (1) of the edging fabric or transferred to the main machine unit, where it is cut by a mesh puller unit Pulled and transported to the cutting area. Next, the cut piece of edge fabric (1) is transferred to the bag folding area, where one end of the bag (ie, the first end (2)) is folded and sealed. This type of sealing can be accomplished by sewing or by applying glue or hot air welding. The conveyor unit transports the fabric edge cuts for further processing. Now, at the second end (3), an "L" shaped cut is made on the second end of the fabric at the second cutting unit (F) with the help of the first and second cutting blades (15, 15A) , the first and second cutting blades (15, 15A) move in the transverse and transverse directions to obtain the desired cut on the bag edge. This type of cutting facilitates the manufacture of the valve in subsequent stages due to the ease of folding the edges during valve formation.

After L-shaped cutting, the bags are transferred to the opening and inward folding unit, where The upper and lower fabric layers are opened (or separated from each other) by a suction member to create a space for tool insertion. The inner tool set moves in the plane of the fabric to form a valve once it is inserted inside by pivoting about a first pivot axis, the inner tool set begins to change its plane by pivoting about a second pivot axis to facilitate valve formation . At the same time, a pusher tool presses the valve formed due to internal tool motion to maintain the valve shape. Next, the cut piece of the valved edge fabric is transferred to a pressing unit, where it is pressed by the pressing unit in the top and bottom layers of the valved fabric to apply uniform pressure so that crease formation occurs. A cutting piece is performed to further cut the edge fabric from the second end in order to obtain a bag of the desired length.

The second end of the cut piece of edging fabric is now folded and sealed. This type of sealing can be performed by sewing, glue application or hot air welding. Finally, the resulting edging bags with valves are stacked and stored.

The bag thus obtained can be made from a mesh sheet with more than one layer, including a front wall, a rear wall, a first side wall, a second side wall, an inner surface, an outer surface, a top and a bottom end. The mesh sheet includes a first layer made of a woven polymer or, as the case may be, nonwoven polymer mesh and is coated with an adhesive or an extrusion coating made of a material such as polypropylene, polyethylene, polyterephthalate A second layer made of any material such as ethylene glycol, polyamide or any combination thereof or paper). Optionally, a third layer is provided which includes oriented polypropylene, biaxially oriented polypropylene, oriented polyethylene, biaxially oriented polyethylene, oriented polyethylene terephthalate, biaxially oriented polyethylene terephthalate diester, oriented polyamide, biaxially oriented polyamide, coated paper or any combination thereof.

In one embodiment, the third layer is a BOPP laminate film with high-end graphics or printing, such that it forms a three-layer structural bag. In a further embodiment, the bag includes at least two layers, such that the first layer is made of a woven polymer or optionally a non-woven polymer mesh, formed by coating A second layer is laid on top of it. Furthermore, the second layer may comprise a printing area such that printing may be accomplished using any such known printing method performed by any other printing machine.

1: Cutting pieces of edge fabrics

1A: The first layer of fabric

1B: Second layer of fabric

2: The first end of the fabric

2A: First folding end

2B: First sealing end

3: The second end of the fabric

3A: Second folded end

3B: Second sealing end

3C: Cut at the second end

4: Suction components

5: Clamp

6: Tubular fabric without borders

7: Internal tools

8: First axis

9: Valve

10: Side pockets

11: leading edge

12: Trailing edge

13: Pusher tool

14: Second axis

15: First cutting blade

15A: Second cutting blade

16: Open and fold the connecting rod group inward

17: Valve forming unit

18: Side insertion tool

A:Network puller unit

B: First cutting unit

C: First folding unit

D: First sealing unit

E:Conveying unit

F: Second cutting unit

G: Open and fold inwards unit

H: Press unit

I: Economical cutting unit

J: Second folding unit

K: Second sealing unit

L: Stacking unit

X: Transpose cutting length

Y: transverse cutting length

L1: Bag length

LC: length

W: bag width

D1: Edge depth

VH: valve height

VL: Valve length

Figure 1 shows the various units of the present invention and the process of manufacturing a side bag with a valve.

Figure 1A shows edge cutting pieces formed from tubular fabric.

Figure 2 shows a block diagram of the process for manufacturing a side bag with a valve.

FIG2A shows a schematic diagram of various units/devices of the apparatus of the present invention.

Figure 3 shows the bag of the present invention.

Figure 4 shows the “L” shaped bag cutouts.

Figure 4A shows the valved bag with valve height and valve depth.

Figure 5 shows the valve forming unit.

Figure 6 shows a second cutting unit for L-shaped cutting at the second end of the bag cutting element.

FIG. 6A shows an opening and folding-in unit with an opening and folding-in linkage assembly for valve formation.

As shown in Figure 1, the edge fabric is unrolled from a roll (a) and cut into cutting pieces (1) of the edge fabric by a first cutting unit (B). Instead of using rolls of edge fabric, one can also use simple rolls of tubular fabric and convert them into edge fabric before entering the first cutting unit (B). Depending on the fabric, cutting can be done by hot or cold cutting. The cutting member (1) of the edge fabric includes a first end (2) and a second end (3), as shown in (b). The cutting piece (1) of the edge fabric passes through the conveyor unit (E) and conveys various bag forming units, such as a bag folding section, in which the first end (2) of the fabric is folded to form As shown in (c), the first folded end (2A) is sealed to form a first sealed end (2B) as shown in (d). Sealing may be accomplished by sewing, hot glue coating, or hot air welding coating, so that the first sealed end (2B) is properly sealed and leak-proof. Now, at the second end (3) of the fabric, a cut (3C) is made by the second cutting unit (F), as shown in (e). The cut thus formed is "L" shaped so that valve formation at a subsequent stage can be easily performed.

An "L" shaped cut is made at the second end (3) of the fabric so that a rectangular portion of the fabric is removed from the front edge (11) away from the rear edge (12), as shown in Figure 4. The cutting of the rectangular cut piece is accomplished with the help of first and second cutting blades (15, 15A) that move simultaneously in the transposition and transverse directions, as shown in Figure 6. The first cutting blade (15) moves in a linear transposition direction with the help of a pneumatic cylinder to form a transverse cutting length (X). At the same time, the second cutting blade (15A) moves in a linear transverse direction with the help of another pneumatic cylinder to form a transverse cutting length (Y). The accuracy of the linear movement of the pneumatic cylinder is achieved with the help of a proximity sensor. Furthermore, the movement of the first and second cutting blades (15, 15A) in the linearly transposed cutting length (X) and the linear transverse cutting direction (Y) can also be achieved with the help of a linear motor or any other linear actuator or any kind of mechanical arrangement (such as ball screw movement).

After the rectangular cut piece is removed from the front edge (11), the bag cut piece moves toward the fabric opening and inward folding unit (G). When the bag reaches the fabric opening and inward folding unit (G), the suction member (4) opens the fabric so that the first layer (1A) of the fabric and the second layer (1B) of the fabric are separated from each other to form a mouth, so that the angle between the two layers of the fabric is close to 180 degrees, as shown in Figure 1 (f). The suction member (4) includes a clamp (5), which separates and holds the first and second layers (1A, 1B) of the fabric with the help of vacuum or any mechanical clamping configuration, so that the first and second layers are far apart to form a mouth.

As shown in Figure 6A, the opening and inward folding unit further includes opening and inward folding An inner folding linkage group (16) in which a structurally identical pair of upper and lower inner tools (7) are inserted into the interior of the bag from the trailing edge (12). A pair of internal tools (7) is required such that each internal tool carries the fabric and is attached separately from the first and second layers of fabric to form a perfect valve. As further shown in Figure 6A, the inner tool (7) is of specially designed curved profile and is inserted between the upper layer of the edge folds and the inner layer of the edge fabric cutter (1). The opening and inward folding linkage group (16) includes an internal tool group (7) which is mounted on a first pivot (8) and swings an angle (θ) around the same first pivot (8). The angle (θ) can be in the range of 85 to 90 degrees, or more specifically, very close to 90 degrees, allowing the valve to be manufactured perfectly, as shown in (g). Oscillation about a first pivot axis (8) may be achieved by a pneumatic rack and pinion cylinder, or may be performed by using a pneumatic cylinder or any kind of rotary motor or mechanical arrangement to provide an accurate rotational movement.

The opening and folding inward linkage group (16) as shown in Figure 6A further rotates about a second pivot axis (14) with its axis parallel to the transposition direction. This second pivot (14) movement of the opening and inward folding linkage group (16) together with the movement of the upper and lower inner tool groups (7) about an axis parallel to the direction of transposition causes the fabric to flex by moving 90 degrees. The second end (3) of the bag is triangular in shape and reaches a plane transverse to the conveying plane. This movement is achieved with the help of a pneumatic cylinder.

After this, the pusher tool (13) presses the triangular shape of the bag to maintain the shape. This triangular formation at the second end (3) of the fabric facilitates valve formation. In the next step, a second pivot axis (14) movement occurs about the axis parallel to the direction of transposition and the inner tool again regains its original plane of the bag conveyor. After this, the inner tool set (7) is mounted on a first pivot (8) and swings around the same first pivot (8) by an angle (θ) in a direction opposite to the initial direction. Thus, a valve is formed at the second end (3) of the fabric. Next, the valve formed at the second end of the bag moves to the pressing unit (H), where the bag is pressed to maintain the shape in front of the second end (3) of the sealing fabric at the second folded end (3A). After the valve (9) is formed and the second end (3) of the fabric is pressed, the bag moves to a Using the economical cutting unit (I), by cutting the second end of the fabric (3), cutting additional fabric and adjusting the height of the valve, the desired bag length can be achieved. After this, the second folded end (3A) as shown in (h) is carried out by the folding device and sealed to form a second sealed end (3B) as shown in (i). Sealing can be accomplished by sewing, hot glue application or by a hot air gun so that the second sealed end (3B) is properly sealed and leak-proof.

FIG. 2 shows a block diagram of the various units involved in manufacturing a side bag (10) with a valve. The side fabric is pulled by a web puller unit (A) and transferred to a first cutting unit (B), where a cut piece (1) of the side fabric is obtained. A first folding unit (C) folds a first end (2) of the fabric sealed by a first sealing unit (D). The fabric is now transferred by a conveying unit (E) to another cutting unit (i.e., a second cutting unit (F)) to form an L-shaped cut. The cut piece closed at one end is now transferred to an opening and inward folding unit (G), which occurs at one side to manufacture a valve. Next, a pressing unit (H) presses the fabric so that the valve is perfectly formed and crease formation occurs. There is an optional cutting unit called the economical cutting unit (I) which is used to cut additional fabric so that the desired bag length can be achieved. In the economical cutting, the second end of the fabric is cut so that the overall length of the fabric can be set. Now, the second folding unit (J) folds the second end (3) of the fabric sealed by the second sealing unit (K), and the manufactured bag is a side bag with a valve at one end (which is now stacked on the stacking unit (L)).

FIG. 2A shows another schematic diagram of a complete machine consisting of a web actuator unit (A) which consists of a roll of edge fabric and which unrolls and conveys the fabric to a first cutting unit (B) according to the machine line speed, wherein the cut pieces (1) of edge fabric are obtained by cutting them to the desired length required to form a bag with a valve. Until this stage, the fabric/cut pieces move in the transverse direction, as shown in FIG. 2A. After the first cutting unit (B), the bag moves 90 degrees in the transposition direction. After this, the first folding unit (C) folds the first end (2) of the fabric sealed by the first sealing unit (D). Now, the fabric is conveyed by the conveying unit (E) to the second cutting unit (F) to form an L-shaped cut. The cut piece, which is closed at one end, is now transferred to the opening and inward folding unit (G), which takes place at one side to produce a valve. Next, the pressing unit (H) presses the fabric so that the valve is perfectly formed and pleat formation takes place. There is an optional cutting unit called the economic cutting unit (I), which is used to cut additional fabric so that the desired bag length can be achieved.

As shown in FIG. 5 , the valve forming unit (17) includes a second cutting unit (F), an opening and inward folding unit (G), a punching/pressing unit (H) and a conveying unit (E). FIG. 5 further shows the moving direction of the cutting piece (1) of the edge fabric so that it enters the second cutting unit (F) and leaves the pressing unit (H) to form a valve.

FIG. 3 shows a bag of the present invention. A side bag (10) with a valve is shown, wherein the valve (9) is made at the second end (3) of the fabric. The side bag (10) further has a first end (2) and a second end (3) as a sealed end, which includes a front edge (11) close to the valve (9) and a rear edge (12) away from the valve.

Figure 4 shows a bag with an "L" cut at the second end (3) of the fabric, the bag having a length (LC), sides obtained after the first folding and sealing of the fabric at the first end (2) Depth (D1), transposed cutting length (X). Transverse cutting length (Y).

Figure 4A shows a bag with bag length (L1), bag width (W), valve height (VH) and valve length (VL). The valve length (VL) must be equal to the sum of the difference between the bag width (W) and the transposed cut length (X) plus the transverse cut length (Y). In addition, the valve height (VH) is equal to the sum of the difference between the bag width (W) and the transposed cutting length (X) and the side depth (D1) minus 35 (mm).

VL =( W - X )+Y

VH =(( W - X )+D1)-35

The table given below provides the range of bag sizes:

The above bag sizes are selected to optimize automated bag manufacturing through creative equipment so that operators will achieve a production rate of 25 to 30 bags/minute. At lower production speeds, those skilled in the art can change the range of bag sizes provided in the table above.

As a preferred embodiment of the present invention, the following steps are involved in manufacturing a bag of the type shown in FIG. 3:

‧Unroll the side fabric roll from one roll.

‧The first cutting unit (B) is used to obtain the cut pieces (1) of the edge fabric from the edge fabric.

‧The cut piece (1) of the edge fabric conveyed on the conveying unit (E) is folded at the first end (2) and sealed by the first sealing unit (D) to form the first folded end (2A).

‧By the second cutting unit (F), the first and second cutting blades (15, With the help of 15A), make a cut at the second end (3) of the L-shape at the second end (3) of the fabric.

‧The opening and inward folding unit (G) swings when the opening and inward folding link group (16) moves around a second pivot (14) and at the same time the internal tool (7) moves around a first pivot (8) With the help of its moving and swinging action, the two layers of fabric (1A, 1B) are opened to form a valve (9).

‧At the same time, the pusher tool (13) presses the valve to form evenly with respect to the bag plane.

‧After this, the bag moves to the economic cutting unit (I) for cutting additional fabric so that the desired bag length can be achieved.

‧In addition, the second end (3) of the fabric is folded at the second folding unit (J) to form a second folded end (3A) and sealed at the second sealing unit (K) to form a second sealed end (3B).

‧Thus, a side bag (10) with a valve at one end is manufactured.

General terms regarding embodiments of the invention do not limit the scope of the invention.

Although the above description contains many particularities, they should not be interpreted as limiting the scope of the present invention, but as an example of its preferred embodiment. It must be recognized that modifications and changes based on the disclosure given above can be made without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should not be determined by the illustrated embodiments, but by the scope of the accompanying invention application and its legal equivalents.

1: Cutting pieces of edge fabrics

1A: First layer of fabric

1B: Second layer of fabric

2: The first end of the fabric

2A: First folded end

2B: First sealing end

3: Second end of fabric

3A: Second folded end

3B: Second sealing end

3C: Cutting at the second end

5: Clamp

7: Internal tools

8: First axis

9: valve

10: Side valve bag

16: Open and fold the connecting rod group inward

F: Second cutting unit

Claims (12)

An equipment for producing side bags with valves from self-edged fabrics, characterized in that the equipment includes a mesh puller unit (A), a first cutting unit (B), and a first folding unit (C) , a first sealing unit (D), a conveying unit (E), a second cutting unit (F) with a first and second cutting blades (15, 15A), an opening and inward folding unit (G ), a pressing unit (H), an economical cutting unit (I), a second folding unit (J), a second sealing unit (K) and a stacking unit (L), wherein the side fabric is made of the mesh The puller unit (A) pulls and is conveyed to a cutting area, where the edge fabric is cut into pieces of desired length, and then the first cutting unit (B) and the first sealing unit (D) are used to cut the first piece of fabric. A fold is made at the end (2) and subsequently sealed at the second end (3), at the second cutting unit (F) with the help of the first and second cutting blades (15, 15A) An "L" shaped cut is made at the second end (3) of the fabric, the first and second cutting blades (15, 15A) moving in transverse and transverse directions to obtain the desired cut at the edge of the bag , then at the opening and inward folding unit (G), the second ends (3) are opened by a suction member (4) or separated from each other so that a space for tool insertion is created, in which the side fabric The second end (3) of the cutting element is folded and sealed to form a valve (9). The device of claim 1, wherein the second cutting unit (F) has a first and a second cutting blade (15, 15A) that moves in the transverse and translational directions with the help of a pneumatic cylinder or any other linear actuator, and wherein a proximity sensor controls the accuracy of the movement of the first and the second cutting blade (15, 15A). The device of claim 1, wherein the device further includes an opening and inward folding unit (G), the opening and inward folding unit (G) comprising an opening and inward folding linkage set (16) having a set of upper and lower internal tools (7) inserted into the interior of the bag at its second end, The inner tool (7) has a curved profile and is inserted between the upper layer of the edge fabric and the inner layer of the cutting member (1) of the edge fabric. The equipment of claim 3, wherein the set of internal tools (7) is mounted on a first pivot (8) and swings around the first pivot (8) at an angle (θ), and the angle (θ) is at 85 Within the range of 90 degrees, preferably 90 degrees. As in the apparatus of claim 4, the internal tool (7) is swiveled about the first pivot axis (8) with the aid of a pneumatic rack and pinion cylinder or may be performed by using a cylinder or any type of rotary motor or mechanical arrangement to provide a precise rotary movement. The device of claim 4 or 5, wherein the opening and inward folding linkage group (16) pivots at a second pivot axis (14) about an axis parallel to the transposition direction to pivot on the third side of the fabric. A triangular fold is formed at the two ends. A method for manufacturing a side bag with a valve from a side fabric using an apparatus as claimed in claims 1 to 6, characterized in that the method comprises the following steps: a. unrolling a side fabric roll from a roll; b. obtaining a cut piece (1) of the side fabric using the first cutting unit (B); c. folding the cut piece (1) of the side fabric at its first end (2) and sealing it to form a first folded end (2A); d. performing an L-shaped cut (3C) at the second end with the help of the first and second cutting blades (15, 15A) moving simultaneously in the transverse and lateral directions on the second cutting unit (F); e. opening the two sides of the fabric using the opening and inward folding unit (G); f. simultaneously with step e, using a pusher tool (13) to press the valve (9); g. moving the bag to an economical cutting position The unit (I) is used to cut the extra fabric so that the desired bag length can be achieved; the second end (3) of the fabric is folded at the second folding unit (J) to form a second folded end (3A) and sealed at the second sealing unit (K) to form a second sealed end (3B), thereby forming a side bag (10) with a valve at one end thereof. The method of claim 7, wherein in step e, the set of internal tools (7) is mounted on a first pivot (8) and swings around the first pivot (8) at an angle (θ), the angle (θ) is in the range of 85 to 90 degrees, preferably 90 degrees. A method as claimed in claim 8, wherein the internal tool (7) is swung around the first axis (8) with the assistance of a pneumatic gear and pinion cylinder. A method as claimed in claim 7, wherein the opening and inward folding linkage assembly (16) pivots at a second pivot (14) about an axis parallel to the rotation direction to form a triangular fold at the second end of the fabric. A bag with side edges made from a cutting piece having a transverse cutting length (X) and a transverse cutting length (Y) by the method of claims 7 to 10, having a bag length (L), a bag width (W) and a side depth (D1), characterized in that a valve (9) having a valve height (VH) and a valve length (VL) is made at the second end (3) of the fabric, having a first end (2) and a second end (3) as a sealing end and a leading edge (11) close to the valve (9) and a trailing edge (12) away from the valve. A bag as claimed in claim 11, wherein the valve length (VL) must be equal to the sum of the transverse cutting length (Y) and the difference between the bag width (W) and the transposed cutting length (X), and wherein the valve height (VH) is equal to the sum of the difference between the bag width (W) and the transposed cutting length (X) and the side depth (D1) minus 35 (mm), which is indicated by the following formula: VL = ( W - X ) + Y VH = (( W - X ) + D1) - 35mm.