WO2021152442A1

WO2021152442A1 - A semi-automated device and a method for cutting advancing web material

Info

Publication number: WO2021152442A1
Application number: PCT/IB2021/050539
Authority: WO
Inventors: Gaurav LOHIA
Original assignee: Lohia Corp Limited
Priority date: 2020-01-29
Filing date: 2021-01-25
Publication date: 2021-08-05
Also published as: TW202202331A; TWI766566B

Abstract

The present invention provides a semi-automated device (15) for cutting web material (3). The device (15) is provided with means for detecting and monitoring defects in the web material (3), a cutter (5) to make cuts in the web material (3), and a unit to separate the defective cut sections (3b) of web material (3). The invention also provides a semi-automated method for cutting web material (3). The device (15) may be a standalone unit used in batch processing in a storage bag making plant, or it may be used in a semi-automated or automated bag conversion line where bags are made from web material (3). In particular, the device (15) is suitable for large or long fabric intended for making bulk storage bags, where wastage of fabric is a major concern. However, it may be used for fabric or web of any size for making bags of any size.

Description

A SEMI-AUTOMATED DEVICE AND A METHOD FOR CUTTING ADVANCING WEB MATERIAL

Field Of Invention

The invention relates to a method and device for cutting fabric. The device has an inline system for detecting defects. The fabric may be a web or plastic woven fabric made of monoaxially drawn polymer slit film tapes, in particular polyolefin slit film tapes, preferably polypropylene slit film tapes. In particular, the apparatus and the method relates to identifying defected portion of large scale or long fabric for bulk storage bag which can be of different shapes, such as square or tubular and notification generation for rejection/ejection.

Background Of Invention

The invention relates to a method and device for cutting fabric. The apparatus has an inline system for detecting defects. The fabric may be a web or plastic woven fabric made of monoaxially drawn polymer slit film tapes, in particular polyolefin slit film tapes, preferably polypropylene slit film tapes, which may be optionally coated with a thermoplastic material on one or two sides. It is important to monitor irregularities, which are characteristic of defected sections of a typical plastic woven fabric. Defects may include weaving defects, fabric ends stuck together, or other similar defects. Some defects may be of cosmetic nature, however some others may compromise integrity and strength of the fabric or affect its other desirable properties such as leak-proof, ultimately rendering it unsuitable for the purpose for which is designed. Downstream processing of the defected fabric results in faulty bags which need rejecting. Worse still, if such defective/faulty bags do not get rejected, they may be filled with material not only leading to spillage and wastage of material but also affecting the quality of the produce or material being stored.

Many solutions are available in the prior art for detecting such defects in fabric. According to US patent application US20120133763 an inspection camera is provided for taking images of the plastic woven fabric, and an analysis unit, which detects irregularities in the weaving pattern of the plastic woven fabric on the basis of the images taken by the inspection camera and which, when detecting irregularities in the weaving pattern indicating a defected section of the plastic woven fabric, triggers an error signal, which actuates, for example, a flashing light or a horn, or which can be fed to a higher-level machine controller. There are further provided an inspection system for monitoring defects of a plastic woven fabric as well as variants of a method for labelling or monitoring, respectively, defects of a plastic woven fabric. However, labelling of defected areas of fabric on a high speed processing unit is a cumbersome and complex operation.

Many powdery or bulkable or other similar types of consumer goods today are filled, stored and transported in big bulk bags made of thick plastic woven fabric and can have different shapes., such as square or tubular. Their load capacity is usually from 300 to 2500 kg depending on the product contained, wherein larger unit contains more. It is essential that the bags made of plastic woven fabric that are used meet the quality requirements for the respective end use purpose.

Bulk bags are generally in use to a rapidly extent for delivering almost any kind of bulk material, and the size of the bulk bags has also increased in recent years, in particular in the case of relatively light materials.

Bulk plastic bags for the packaging of particulate goods such as, for example, powder/chemical have to be sufficiently firm and dust-tight in order to prevent contamination or exit of particles, respectively, during the process of filling, storage as well as transportation and, hence, also contribute to the protection of the environment. Plastic bags for the packaging of free-flowing chemicals, furthermore, have to meet in addition strict requirements in terms of occupational safety as well as requirements regarding the resistance of the material used against weather influences.

Producers and traders, respectively, of bulk packaging bags made of plastic material are increasingly facing the problem that operators of automated filling plants detect a defected bag in the course of incoming goods inspections on a random basis, so that a complete pallet or charge of hundreds or thousands of plastic bags will be reclaimed and will have to be taken back by the supplier. The economic damage arising thereof is tremendous.

First approaches of individual bulk bag producers to detect defects in the material already during the production of a plastic woven textile early on and to label these manually by means of coloured marks have not been fully developed so far.

Because of fast running processing machines, which will achieve web rates of the plastic woven fabric of up to 100 m/min, a complete and purely optical inspection in regard to defects by the operating personnel is virtually impossible. A coloured marking of a defect, for example at a flat web of material, which in the subsequent process steps of the bag production is formed or closed, respectively, into a fabric tube, may thus later on be situated on the inside of this fabric tube and will thus not be detected in a down-stream optical quality control. Furthermore, depending on the customer's requirements, defects of certain size and below may be acceptable, therefore there needs to be a distinction made regarding the size of defects that need to be eliminated.

Large-scale or long defects occurring along several metres of a section of the plastic woven fabric are more prone to be detected by the operating personnel than small-scale defects.

A reliable monitoring system for detecting a defected section of a plastic woven fabric, the sensitivity of which in regard to the defect detection may be adjusted according to the customer's requirements, which marks all defects occurring and also detects these following one or several subsequent process steps of the plastic woven fabric, and cutting the said defected fabric only by cutter unit which in turn minimises the waste collection of the defective fabric and in turn save fabric length which has so far not been known.

Thus, there is a requirement for method and device for detecting above stated defects and cutting it there by for large scale or long fabric for big bulk bags.

Objects of Invention:

The main objective of the present invention is to provide a device for cutting of fabric and simultaneously detecting defects in a plastic woven fabric.

Another objective of the present invention is to provide a defect detection system for monitoring defects using such a device for detecting defects.

Yet another objective of the present invention is to monitor the defects in large scale or long fabric and minimize wastage after cutting.

According to the invention, these objectives are achieved by providing a cutting device where in detection of defected areas of fabrics are detected. The co ordinates of the defected areas are noted. The progress of the defected areas of fabric down the line is monitored through the fabric cutting unit. The cut pieces of fabric containing defects are identified. Cut pieces containing defects are manually cut as per customer observation and requirement thereby minimizing wastage after cutting and ejected normal cut pieces are separated.

Brief description of figures:

Figure 1 shows the scanner and defects detector (4) and cutting unit (5) for bulk bags of the invention. Figure 2 shows an embodiment of the system of invention

Figure 3 shows a plan view schematic of the invention a schematic of web material with defects

Figure 4 shows a schematic of communication between control units of defect detection device, cutter unit and a control unit

Summary Of Invention:

The present invention provides a semi-automated device (15) for cutting web material (3). The device (15) is provided with means for detecting and monitoring defects in the web material (3), a cutter (5) to make cuts in the web material (3), and a unit to separate the cut sections of web material (3) that are determined to be defective.

The present invention also provides a semi -automated method for cutting web material (3) using the device disclosed here. The device (15) may be a standalone unit used in batch processing in a storage bag making plant, or it may be used in a semi-automated or automated bag conversion line where bags are made from web material (3). In particular, the device (15) is suitable for large or long fabric intended for making bulk storage bags, where wastage of fabric is a major concern. Flowever, it may be used for fabric or web of any size for making bags of any size.

In a key aspect of the invention, the semi-automated cutting device (15) comprises of a cutter unit (5), a scanner and defects detector (4), and a defect management control unit (7) wherein defect management control unit (7) monitors the progress of the defect on the travelling web material (3). A signal or an alarm is generated by control unit (9) which in turn stops the cutting device (15) ) for manual inspection of the traveling web material (3) in order to decide the location of the cut to be made in the web material (3). The device is then restarted, and a cut is made using the cutter (5). Manual separation of the defective portion is done into rejection zone (12) from the main flow of web material.

The manual intervention allows a section of web material (3) carrying defects to be identified - depending on the location of defects and depending on the length of defects-free length of web material (3) between any two defects, the operator may manually operate the cutter to cut out the defects-free length of web material (3). This customised cutting of web material (3) allows minimisation of wasted fabric.

The inventive device will reject only that portion or length of the fabric which is defective, thus save the long or large scale length of required advancing web (3).

According to another aspect of the present invention, it also provides a device(4) for detecting defected areas of large scale or long web material (3) for bulk storage bags which also comprises a scanner and defects detector (4). The coordinates of the defected area at the time of the detection are noted in the defect management control unit (7) which communicate to the control unit (9) that a defective portion of web (3b) has been detected. The control unit (9) then issues a signal to stop the advancing web (3) just before the cutter unit as per defined length (LI), so that the operator can visualise the location of defects (8), thereby advancing the web material (3) and issues instruction to the cutter (5) to cuts web material (3) to separate the defective web piece (3b) from the main fabric. Such operation of rejecting defective web (3b) is done manually from the main flow of web material.

List of parts:

1 - fabric or web material roll

2 - roller 3 - fabric or web material; 3a - defect free web cut piece; 3b - defective web cut piece;

4 - scanner and defects detector

5 - cutting unit or a cutter 6 - cut piece stacking platform7- defect management control unit

8- defects

9 - device control unit

10- sensing device

11- backlight unit 12- rejection zone

13- downstream

14- transport table or conveyor belt

15 - semi -automated cutting device

16 - delimiting cut lines or delimiting cuts

Detail description of invention

The general setup of the semi-automated cutting device (15) of the invention is shown in Figure 1. It includes a scanner and defects detector (4) and cutting unit (5) of the invention designed for big bulk bags. It also shows a fabric roll (1) from which the fabric (3) is unfolded over a number of rollers (2), following which it is scanned by the scanner and defects detector (4). The scanner and defects detector (4) may be of a type that is able to detect various types of defects. The term defect (8) refers to any unacceptable irregularities in the web material (3) from the perspective of suitability for the purpose of which, the web material (3) is intended. Defects (8) may be holes, uneven pattern, missing wrap end, missing weft, crushing of weft, uneven edge trim, web joints, one or more layer of web, foreign particles, or any combination of these defects. Therefore, the scanner and defects detector (4) may be a reliable web monitoring system that uses a sensing device (10) which monitors the fabric (3) as it unwinds from a fabric roll (1). The sensing device (10) may be a camera or infrared sensors, or thickness sensors or image processing device.

The semi-automated cutting device (15) also has a cutter unit (5) to make transverse cuts in the web material (3) at locations identified by the defect detector and scanner (4). The cut pieces containing defects-free web (3a) are stacked on a cut-piece stacking platform (6), while the defective pieces/cut lengths (3b) are sent manually to the rejection zone (12).

The device (15) also has a programmable control unit (9) that controls activities of the device (15). The locations of defects - either as single or isolated defects or as a defects cluster - are variable. The aim of the invention is to maximize the defects-free cut length of the web material (3) and minimize the length of the defective portions of the web material (3). Depending on the requirements of individual customers, and the end purpose for which the defects-free web material is used, the operator may set a required length (L) of individual defects-free cut pieces (3a) of web bacterial (3). The device (15) allows the operator to identify the defects (8) or defects clusters and cut out the portions containing it using the cutter (5). The device (15) also allows the defects-free portion of the web material (3) to be cut into pieces of required length L.

The control unit (9) stops the advancement of the web material (3) upon detection of a defect (8) or cluster of defects just before the cutter (5) at length (LI) which can be changed as per individual customer requirement or which can be pre-set at the minimum distance in order to save web material (3) length, so that the operator of the device (15) may inspect the area of the web material (3) containing the defect (8).

In one embodiment, the scanner and defects detector (4) is placed such that the web material (3) being scanned is horizontal, so that the inspection activity by the operator becomes convenient. Upon stoppage of the advancement of the web material (3), the operator inspects the web material (3) and determines the location of the cut. As shown in Figure 3 by dashed lines, he may determine the location of the cut lines (16) to include single defects (8) or the defects cluster, as the case may be, so that a defective portion of web material (3) is identified for cutting. The operator then starts advancement of the web material such that the cutter (5) makes delimiting cuts (16) in the web material (3) at the locations identified by the operator to make a defective web cut piece (3b) eliminated. Delimiting cuts are a pair of cuts that define the defective cut piece (3b).

Once the delimiting cuts (16) have been made, the operator restarts the cutting device (15) for advancement of the web material (3) using the control unit (9). The web material is scanned continually, and if there is any length of defects free web material (3), exceeding the predetermined length L, the advancing web material pauses at the cutting unit to make transverse cuts in the web material (3) so that individual pieces (3a) of defects-free web material are made. The control unit (9) ensures that advancing web material (3) pauses before each such cut and starts advancing again following the cut. Once the next defect (8) is detected, the process of identification of the defective portion of web material (3) to be cut is repeated.

The defective cut piece (3b) is separated manually from the main flow and sent to a rejects zone (12).

The sensitivity or accuracy of the scanner and defects detector (4) may be set to the individual customer requirement, such that customer/operator has freedom to predetermine the cut length which is required after detection of the first defect in the advancing web (3), thereby stopping the device subsequently give the command to the cutter unit (5) to cut the fabric (3) and separate it from advancing web (3) by sending it manually to the rejection zone (12). The term web material (3), web and fabric are used interchangeably in the following description.

The web material (3) may be in form of plastic film, non-woven material, paper, woven web material, woven plastic web material, or a composite material made from any of these materials particularly is of large scale or long fabric used for big bulk bags.

Figure 2 shows another embodiment of the system of invention wherein the plane of the web that is being scanned is vertical. In another embodiment, the plane of the web that is being scanned may be at any angle with horizontal (not shown). Position of the defect detector and scanner (4) can be placed according to the customer requirement.

The sensing device (10) may be a camera or infrared sensors, or thickness sensors or even image processing device.

As illustrated in Figure 3, one of the aspects of the invention shows cutting device (15) comprising of cutting unit (5) and scanner and defects detector (4) in plan view. The scanner and defects detector (4) comprises of a sensing device (10) which monitors advancement of the fabric (3) and a backlight unit (11). The scanner and defects detector (4) is mounted along the path of the traveling web material (3) as it unwinds from the fabric roll (1). The sensing device (10) may be a camera or infrared sensors, or thickness sensors or even image processing device that serves as light sensing device. A defect management control unit (7) processes the data on the quality of the web material (3) received from the sensing device (10). Upon detection of any defects (8) or irregularities in any area of the advancing fabric (3), a signal is sent by the defect management control unit (7) to the device control unit (9) which in turn commands the device to stop. The location of the defect (8) upon stoppage of the device is identified by the operator and operator, through the device control unit (9), initiates a signal to the cutter unit (5) to cut only the defective web (3b) length and sent the defective cut piece (3b) of the web material manually to the rejection zone (12).

The device (15) according to the invention has a completely separate drive- controlled fabric feeding unit that controls the operation of the web material roll (1) and a cutting unit (5)/ profile cutting section.

A schematic of the device (15) with advancing web material (3) with a number of defects (8) is shown in Figure 3. The defects (8) within the main material are denoted as Dl, D2, D3, and so on.

A provision is also made for a suitable system for monitoring speed of the fabric feed roller (2) using encoder or similar device which communicates with defects management control unit (7). On the basis of the speed of the feed rollers (2), the defects management control unit (7) determines the linear speed of the advancing web material (3), which in turns determines the speed of the web material (3) travelling towards the cutter unit (5). It is important to know the speed of web material (3) so that once the defects (8) in the of web material (3) are detected and their location identified, the device (15) is stopped by the control unit (9) just before the cutter unit (5) so that an operator can cut the defective web material (3b) and convey the same to the rejection zone (12) separating it from the advancing defects-free web material (3b).

The operator is able to, using the control unit (9), make defect-free cut pieces of predetermined length (L) in absence of defects.

The sensitivity or accuracy of the web defect management control unit (7) may be set to the individual customer requirement.

According to the present invention, as soon as the sensing device (10) senses an abnormality in the image intensity compared to the luminosity value greater than the pre-set/control value, a signal indicating detection of a defect (8) is generated by the defect management control unit (7). The portions of the fabric containing the detected defects (the defective portions) (Dl, D2, D3 and so on) keep traveling in the direction of their travel and their progress is monitored. The defect management control system (7) communicates to the control unit (9) that a defective portion of web (3b) has been detected. The control unit (9) then issues a signal to stop the advancing web (3) just before the cutter unit as per defined length (LI) which can be pre-set as per the customer requirement, so that the operator can visualise the location of defects (8), thereby advancing the web material (3) and issues instruction to the cutter (5) to cut web material (3) to separate the defective web piece (3b) from the main fabric. By setting the pre-set value to minimum the fabric saving can be monitored and executed.

As an example of how the device (15) results in saving of web material (3), suppose if the required material for the big bulk bag is 10 metres of defect free fabric (3a) to be cut and defect (8) arise after 4 metres of fabric length so the inventive system will only cut the 4 metres of fabric (3) and saving another 6 metres rather than cutting full 10 metres of web material (3). The length (LI) of the web material (3) just before the cutter unit (5) which is contains defects (8) can also be optimised as per the customer requirement. Further defective fabrics (3b) are collected in a reject zone (12). The required material which is defect free web (3a) cut pieces enter the downstream (13) bag-making line.

Further on the same inventive cutting device (15) if the required material for the big bulk bag is 6 metres of defect free fabric (3a) to be cut and defects (8) arise after 1 metre of fabric length so the inventive system will only cut the 1 metre of fabric (3) and saving another 5 metres rather than cutting full 6 metres of web material (3). The length (LI) of the web material (3) just before the cutter unit (5) which is contains defects (8) can also be optimised as per the customer requirement. Further defective fabrics (3b) are collected in a reject zone (12). The required material which is defect free web (3 a) cut pieces enter the downstream (13) bag-making line.

In another aspect of the invention, there is provided a driven roller (2) facilitating a controlled fabric movement on actuation of the defective portion signal. This enables to maintain the cutting unit (5) output.

The number of defects (8) and their distribution along the length of the advancing fabric (3) determines the speed of the feed section. The speed is controlled such that the normal pieces moving onto the downstream (13) production line continue to do so at the set frequency/speed.

A further advantage of the cutting device (15) of the invention is that if defective web (3b) is detected then only that small length portion which contain defects (8) is rejected whereas in conventional system the pre-set value of the required web material (3) for bag manufacturing is rejected fully and therefore normal fabric which is defect free (3a) after defective portion, is considered into required material cut length of fabric (L).

The fabric cutting unit (5) may have one or more type of fabric profile cutting device which can be hot cutter by heating the web, cold cutter such as sharp knife or blade installed after the scanner and defects detector (4). The operation of any profile cutter will be done on basis of defective signal from defect management control unit (7).

It is thus evident from the foregoing discussion that the present invention has following items.

1. A semi-automated device (15) for cutting advancing web material (3) being fed from a roll (1) and traveling over a set of rollers (2) towards a cutter (5) characterised in that said device comprises: a scanner and defects detector (4) for identifying and monitoring defects (8) in said web material (3), a defects management control unit (7), a rejection zone (12) to separate the cut sections (3b) of web material (3) that are determined to be defective, and a control unit (9), wherein said scanner and defects detector (4) scans the web material for defects (8) and sends data on the quality of web material (3) to defects management control unit (7), said defects management control unit (7) processes the data received from the said scanner and defects detector (4), and identifies locations of defects (8), said control unit (9) controls the advancement of said web material (3), and raises an alarm and stops it from advancing upon detection of said defect (8) manually, instructs the cutter (5) to make delimiting cuts (16) on either side of the detected defects (8), and restarts advancement of said web material (3) once a defective cut piece is cut from said web material (3), said control unit (9) instructs the cutter (5) to make defect- free cut pieces of predetermined length (L) in absence of defects. A method for cutting advancing web material comprising the steps of: a. scanning said advancing web material (3) for defects (8) using said scanner and defects detector (4), b. upon not detecting any defects for a length exceeding a predetermined length L, cutting said web material (3) into defects free web pieces (3a) and sending said defects free web pieces for further processing, c. upon detecting defects (8) on said advancing web (3), said defect management control unit (7) raising an alarm, d. by using the control unit (9) stopping the advancement of said web material (3) to being delimiting cut line (LI) at a predetermined distance from the cutter (5), e. inspection of the detected defects (8) by an operator, f. by using the control unit (9) bringing each of the delimiting cuts (16) to the position of cutter (5) sequentially, stopping the advancement of said web material (3), and making delimiting cuts (16) using the cutter (5) to make the defective piece (3b), g. sending said defective piece (3b) to a rejection zone (12).

Figure 4 shows a flow chart of the process of the communication between some of the various units of the cutting device, wherein following steps are carried out: a. Defects (8) or irregularities in any area of the advancing web material (3) inspect by scanner and defects detector unit (4) b. Scanner and defects detector unit (4) communicate with said defect management control unit (7) to maintain a database of the defects (8), their locations at the time of detection, and monitoring the process of defects (8) along the advancing web material c. Defect management control unit (7) communicate with device control unit (9) as per defect (8) d. If the signal conveyed to the control unit (9) for defective web, then it generates alarm and stops the device (15) so that operator may visualise the defect (8) and provide signal to cutter unit (5) to the cut the defective web and send it manually to rejection zone (12) e. Wherein if the signal conveyed to the control unit (9) for defect free web, no signal is provided to cutter unit (5) by the operator and as per the regular cutting process, the cutter unit (5) cut the defect free web (3a) and send it to downstream (13) without interruption. It is evident from the foregoing discussion that the invention has the following preferred embodiments. In one preferred embodiment, it provides a semi- automated cutting device (15) for cutting advancing web material (3) being fed from a roll (1) and traveling over a set of rollers (2) towards a cutter (5). The inventive aspect of the device is that it comprises a scanner and defects detector (4) for identifying and monitoring defects (8) in said web material (3); a defects management unit (7); a unit to separate the cut sections (3b) of web material (3) that are determined to be defective, and a control unit (9). These components interact in a unique way to achieve the objects of the invention. The scanner and defects detector (4) is capable of scanning the web material for defects (8) and sending data on quality of the web material (3) to defects management unit (7). The defects management unit (7) is capable of processing the data received from the said scanner and defects detector (4), and thereby identifying the locations of defects (8) on the web material (3). The control unit (9) is capable of controlling the advancement of the web material and raising an alarm. Further, the operator is able to, using the control unit (9) to stops it from advancing upon detection of said defect (8) and instructing the cutter (5) to make delimiting cuts (16) on either side of the detected defects (8), and thereafter, restarting the advancement of said web material (3) once a defective cut piece is cut from said web material (3).

In another preferred embodiment, the invention also provides a semi -automated method for cutting advancing web material (3). It uses the apparatus disclosed in the previous embodiment and carries out the objects of the invention using a number of steps. First the device scans advancing web material (3) for defects (8) using the scanner and defects detector (4). If no defects are detected in a length of L - that is the length predetermined to be the required length to make a product of certain size - the cutter (5) cuts the web material (3) into defects free web piece (3a) and sending said defects free web pieces for further processing. If a defect or set of defects (8) is detected, defect management unit (7) raises an alarm, and by using the control unit (9) stops the advancement of said web material (3) so that a delimiting cut line is set at a predetermined distance LI from the position of the cutter (5). Next, the operator inspects the detected defects and instructs the control unit (9) to bring each of the delimiting cut (16) to the position of cutter (5) sequentially, and to stop the advancement of said web material (3), and to make delimiting cuts (16) using the cutter (5) to make the defective piece (3b); and after this, sending the defective piece (3b) to a rejects zone (12).

While the above description contains much specificity, these should not be construed as limitation in the scope of the invention, but rather as an exemplification of the preferred embodiments thereof. It must be realized that modifications and variations are possible based on the disclosure given above without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.

Claims

Claims:

1. A semi-automated device (15) for cutting advancing web material (3) being fed from a roll (1) and traveling over a set of rollers (2) towards a cutter (5) characterised in that said device comprises: a scanner and defects detector (4) for identifying and monitoring defects (8) in said web material (3), a defects management unit (7), a rejection zone (12) to separate the cut sections (3b) of web material (3) that are determined to be defective, and a control unit (9), wherein said scanner and defects detector (4) scans the web material for defects (8) and sends data on the quality of web material (3) to defects management unit (7), said defects management unit (7) processes the data received from the said scanner and defects detector (4), and identifies locations of defects (8), said control unit (9) controls the advancement of said web material (3), and raises an alarm and stops it from_advancing upon detection of said defect (8) manually, instructs the cutter (5) to make delimiting cuts (16) on either side of the detected defects (8), and restarts advancement of said web material (3) once a defective cut piece is cut from said web material (3), said control unit (9) instructs the cutter (5) to make defect-free cut pieces of predetermined length (L) in absence of defects (8).

2. The semi-automatic device (15) as claimed in claim 1, wherein said scanner and defects detector (4) is oriented for scanning said web material (3) in its horizontal configuration.

3. The semi-automatic device (15) as claimed in claim 1, wherein said scanner and defects detector (4) is preferably oriented for scanning said web material (3) in its vertical configuration.

4. The semi-automatic device (15) as claimed in claims 1 to 3, wherein said scanner and defects detector (4) consists of at least one sensing device (10) and at least one backlight unit (11) mounted along the path of the traveling fabric (3) after it has unwound the fabric roll (1).

5. The semi-automatic device (15) as claimed in claims 1 to 4, wherein said sensing device (10) is selected from a group consisting of camera, infrared sensors, thickness sensors, image processing device.

6. The semi-automatic device (15) as claimed in claims 1 to 5, wherein said stoppage of the advancing web material (3) is to bring said delimiting cut (16) to a predetermined distance (LI) from said cutter (5).

7. A semi-automated method for cutting advancing web material (3) using the apparatus as claimed in claims 1 to 6, characterised in that said method comprises the steps of: a. scanning said advancing web material (3) for defects (8) using said scanner and defects detector (4), b. upon not detecting any defects for a length exceeding a predetermined length L, cutting said web material (3) into defects free web pieces (3a) and sending said defects free web pieces for further processing, c. upon detecting defects (8) on said advancing web (3), said defect management unit (7) raising an alarm, d. by using the control unit (9) stopping the advancement of said web material (3) to being delimiting cut line (LI) at a predetermined distance from the cutter (5), e. inspection of the detected defects (8) by an operator, f. by using the control unit (9) bringing each of the delimiting cuts (16) to the position of cutter (5) sequentially, stopping the advancement of said web material (3), and making delimiting cuts (16) using the cutter (5) to make the defective piece (3b), g. sending said defective piece (3b) to a rejection zone (12).

8. The semi-automated method as claimed in claim 7, wherein said scanning of said web material (3) is carried out in vertical configuration of said web material (3).

9. The semi-automated method as claimed in claim 7, wherein said scanning of said web material (3) is carried out in horizontal configuration of said web material (3).