MXPA06005976A - An optical sealing clamp and a method for sealing and cutting polymeric sheets with a laser - Google Patents

Abstract

The invention is specially directed towards intermittent motion packaging machines where the packages are momentarily immobilized at a forming station for the time duration of the package sealing and cutting. The polymeric sheets or films (24) are sealed and cut after being exposed to a laser beam (20) in a controlled and optimized manner. The laser beam (20) is shaped with appropriate optical elements (56) to provide a desired intensity profile in the section of the films to be sealed or sealed and cut. With this method, a package (15) can be sealed and cut simultaneously in one exposure step. An optical clamp (30, 31) holds the films (40, 41) together while they are being sealed by the laser (20). The optical clamp (30, 31) can reflect back to the films, partially or totally, the laser beam intensity that has not been previously absorbed. The optical clamp (30, 31) further allows to monitor the sealing and cutting process while the process is being performed.

Description

AN OPTICAL SEALING BRUSH AND A METHOD FOR SEALING AND CUTING POLYMER LEAVES WITH A LASER Technical Field The invention relates to a method and apparatus for sealing or cutting polymer sheets by laser radiation. More specifically, it relates to sealing and optically cutting with a laser sheets or polymeric films that are used in fast packing machines such as forming, sealing and filling machines at high speed. BACKGROUND OF THE INVENTION In the packaging industry, the welding and cutting of polymer sheets is a very important issue. The polymeric materials are used to manufacture all kinds of packages and, in the case of the food industry, these packages can be, for example, bags containing a liquid such as milk or sealed bags containing solid food. For the food industry it is a requirement to have a packaging process that is reliable, of very high quality and hygienic. In addition, the packaging process must be fast, efficient and easy to control. In the packaging / filling / sealing industry at high speed, conventional machines fall in two. different categories, that is machines of continuous and intermittent movement. In continuous motion machines, packages are formed and sealed at a fixed speed and in intermittent motion machines, the package is momentarily immobilized in a cutting station for the duration of the sealing process. The forming / filling / sealing packaging machines that are used to produce milk bags are intermittent motion machines that can typically form / fill / seal milk bags with a high speed of more than 1 liter per second. These machines use a heating system to seal and cut, in an operational stage, the polymer films thus forming a bag or sachet. Heating the polymer films locally has the effect of welding the films together creating simultaneously a region of two seals separated by a region where the films are cut. The process must be controlled very well since too much heat can damage the integrity of the films as well as insufficient heat will poorly weld the films. In the high-speed forming / sealing / packaging industry, the sealing systems that are generally in use, use an electrical resistance wire that is heated by an electrical impulse. The heated wire is brought into contact with the films where the films are intended to be sealed and cut, and the heat of the wire is transferred partially to the films thus creating the seal. An example of this type of machine can be found in the US patent. 6,237,308 Bl. Although this system allows a high-speed packaging and is a well-mastered process, it has some disadvantages. The first disadvantage of this system is that the hot wire must come into contact (directly or indirectly by means of a disposable release sheet) with the films to transfer the heat to the films. This can lead to contamination problems and the hot wire and / or the release sheet should be changed frequently. The current technique is also a not very efficient process since the area of film that is heated by this process is much larger than what is really needed to make the seal. Finally, since the hot wire is located in a mechanical fastener that is subject to mechanical vibrations to put the films in contact, which can affect the quality of the seal. It is known to use lasers to seal and cut polymer films in a continuous sealing apparatus from the U.S. Patent. 6,207,925 Bl. Three laser beams are controlled to perform the seal-cut-seal action between two adjacent packages. Each laser is dedicated to either sealing or cutting the films.

Due to the continuous movement of the films, the time is extended for the laser beams to cut and seal substantially throughout the packaging cycle. The teachings of the U.S. Patent 6,207,925 Bl can not be quickly adapted for use with intermittent motion forming / filling / sealing machines and precision control of the point beam in the case of continuous motion machines remains costly. Therefore there is a need for a method and apparatus for improving the sealing and cutting process of a high-speed packaging machine, with the purpose of increasing the efficiency of the process, to reduce the mechanical contact between the heating source and the films and to increase the total life of the components of the machine. DESCRIPTION OF THE INVENTION According to the foregoing, the objective of the present invention is to provide a method to optically seal and cut polymer films for packaging machines based on an optimized optical system using a laser or several lasers and an optical fastener special. The present invention can be applied to any polymer sheet or film that requires welding or cutting. The method allows a more efficient optical sealing and cutting process compared to previous methods found in the prior art.

A feature of the present invention is to provide a method for optically sealing and cutting polymer sheets or films with at least one laser beam having an intensity profile shaped for the purpose of obtaining a sealing operation in an exposure step. / cut / sealed. The method comprises: forming the at least one intensity profile of a laser beam using an optical device to provide the desired intensity profile; overlay and contact at least two of said films with each other; and exposing an area of the films, the area that is a stamp-cut-seal volume, to said desired intensity profile for the purpose of obtaining in an exposure stage two sealing regions wherein the films are sealed together and they separate by a cutting region where the films have been cut. It is another feature of this invention to further improve the efficiency of the sealing and cutting process by causing the films to absorb more intensity of the laser beam, the method comprising: superposing and contacting at least two films with each other; exposing an area of the films, the area corresponding to the sealing volume, to at least one laser beam, providing an incident laser beam intensity, for the purpose of sealing or cutting the films; increase an intensity of the laser beam in the sealing volume by partial or total re-injection of the intensity of the laser beam that has not been absorbed by the films, back to the films using at least one reflector device, improving thus the efficiency of the sealing or cutting method causing the films to absorb more intensity of light from said intensity of incident laser beams. It is another feature of the present invention to provide an optical seal fastener for optically sealing or cutting sheets or polymeric films with at least one laser beam, the fastener comprising: two jaws wherein at least one of said jaws can be moved to allow the fastener to be closed and opened; the other jaw, is an optical jaw, having an optical window to allow the laser beams to pass through it and wherein said window is wide enough to allow to optically seal or cut the full width of said films; and support means to interconnect said jaws and to allow a controlled opening and closing of the fastener.

It is a further aspect of the fastener described above, that of providing an increase in the intensity of the laser beam towards the films by causing said contact surface of the jaw to partially or totally reflect the intensity of the laser beam that has not been absorbed for the movies, back to the movies, thus increasing the efficiency of the sealing and cutting process. It is a further aspect of the previously described fastener to provide a further increase in the intensity of the laser beam towards the films by causing said optical jaw surface to partially or fully reflect the intensity of the optical beam that has not been absorbed by the films, back to the movies, thus increasing even more the efficiency of the sealing and cutting process. It is a further aspect of the previously described fastener to provide a further increase in the intensity of the laser beam towards the films by causing said optical jaw surface to be exposed to the intensity of laser beams not absorbed by the shaped films to allow three reflections back and forth from one clamp to the other, thus allowing four passes of laser beam to the films. It is another feature of the present invention to provide a method for monitoring the sealing and cutting process by optically representing by an image the quality of the sealing and cutting through the window of the fastener while the sealing and cutting process is being carried out. According to an even broader aspect of the present invention, two packaging methods are provided which offer sealing and cutting efficiency and which solve or reduce some disadvantages of the prior art due to the direct contact of the heating source with the films , such as contamination of the packages and the short life of the sealing elements. Both methods use at least one optical fastener whose characteristics have been described above. The first method of packaging is a method of forming, sealing and cutting optical and filling a sachet with a liquid at high speed. The method comprises: i) providing a vertical tube, made of polymeric film, that is partially or completely filled with a liquid or that is being filled with a liquid; ii) flattening a filled section of said tube for a determined time interval using an optical sealing fastener for sealing and optical cutting said section of said tube; iii) exposing said section of said tube to at least one laser beam intensity, for a time exposure interval t, to heat said section of said tube in a controlled manner, said intensity is modeled to obtain an intensity profile desired and to provide a corresponding absorbed intensity profile in said section of said tube; iv) providing a desired amount of heat to said section of said tube by optimizing a combination of intensity profile absorbed, said time exposure interval and, if required, heating said optical sealing fastener; v) obtaining as a result two seals through said section of said tube and simultaneously cutting said tube between the seals, to form an upper seal for a filled sachet that is separated from said tube and a lower seal for said vertical tube. The second packaging method is a method of sealing or sealing-and-cutting packages made of sheets and polymeric films using at least one laser source and at least one optical sealing fastener, the method comprising the steps of: partial or fully formed package that is partially or completely filled with its content or that is being filled with its content; overlaying and contacting an inner wall of a section of said package for subsequent sealing by means of an optical sealing fastener; exposing said section of said package to at least one laser beam intensity, for a time exposure interval t, to heat, in a controlled manner, said section of said package, said intensity is modeled to obtain a profile of desired intensity and to provide a corresponding absorbed intensity profile in said section of said package; providing a desired amount of heat to said section of said package to perform either a sealing operation or a sealing-and-cutting operation, optimizing a combination of said absorbed intensity profile, said time exposure interval and if necessary , heating said optical sealing fastener; obtaining as a result in the case of the sealing operation, a seal through said section of said package and in the case of a sealing-and-cutting operation, two stamps through said section of said package and simultaneously a region Cut between the two seals where the package is cut. The packaging methods described above can further provide monitoring of the sealing or sealing-and-cutting operation by inspection, using an optical detection assembly, of the package in the sealing phase through the optical window of the optical sealing fastener, while the sealing or sealing-and-cutting operation is carried out. The packaging methods described above may further comprise the partial or total re-injection of the intensity of the laser beam that has not been absorbed in step iii) by means of a reflective property of the optical sealing fastener, to enhance a controlled way, the heat in the section of the films to be sealed and cut. BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a drawing showing a vertical machine that is forming pouches, filling them with a liquid and sealing them; Figure 2 is a graph showing the intensity distribution of laser lightmark at the level of the films along the length of the seal (y axis) and in the perpendicular direction (x axis); Figure 3A and Figure 3B show a fastener in the open position (3A) and in the closed position (3B). One of the jaws has the opening; Figure 4 shows a fastener with a ZnSe window; Figure 5 is a side view of a fastener in the closed position. The fastener is contacting two flexible polymer films and an incoming laser beam is sealing and cutting the films; Figure 6 is a side view of a fastener with a jaw shaped to apply a tension on the films and reflect partially or totally the light that had not been absorbed by the films, back to the films; Figure 7A is a close-up illustration of the sealing region wherein the incident laser beam is propagating through the two films and reflected back to the films by means of the jaw. Below is the evolution of the beam intensity along the sealing volume in the direct direction in Figure 7B and in the backward direction (Figure 7C). Figure 7D shows the intensity of the absorbed beam. Figures 7E, 7F, 7G and 7H show the same information in the case where the films are composed of a slightly absorbent layer and a strongly absorbent layer; Figure 8A is a side view illustration of a fastener with both jaw configurations allowing 4 passes of laser light in the films, and Figure 8B shows the same fastener used with two laser beams; Figure 9 shows a side view of a fastener that uses air currents to contact the films; Figure 10 is a side view of a fastener wherein a mirror adhered to it, reflects the unabsorbed light back to the film; Figure 11 is a schematic illustration of an optical system used to provide a luminous mark of elongated lasers on the films to allow sealing and cutting of the full width of the films; Figure 12 is a schematic illustration (top view) of the scanning system of the laser beam that allows to seal and cut the full width of the films. The bra is shown from above; Figures 13A, 13B and 13C are schematic illustrations of other packaging systems; Figure 14 is a schematic illustration of an optical arrangement for monitoring the sealing process of two films. It will be noted that throughout the accompanying drawings, similar characteristics are identified by means of similar reference numbers. MODALITIES FOR CARRYING OUT THE INVENTION In this detailed description of the preferred embodiment, we will focus on the intermittent form / fill / seal machines of the food industry (FFS) where the package is momentarily immobilized in a cutting station for the duration of time of the sealing process. Figure 1 is a schematic illustration of a preferred embodiment of this invention where a vertical form / fill / seal machine (VFFS) is shown. VFFS machines are commonly used to manufacture milk bags. In this type of machine, a tube 24 manufactured from a flexible polymer film is continuously filled with a liquid 28 by means of a device that supplies liquid 22. The tube 24 has previously been formed. (not shown in this figure) from a roll of flexible polymer film 26 that has been sealed vertically using a vertical sealant fastener. A horizontal optical fastener having two jaws 30, 31 that open and close repeatedly, allows the production or filling of bags 15 in a ratio of approximately 1 sachet per second. While it is closed on the tube, the fastener momentarily immobilizes it for the duration of the sealing process, after which it is reopened to allow another length of tube to pass. The present invention proposes a method and a special optical fastener to improve the efficiency of the optical process of sealing and cutting of flexible films in the context of intermittent machines at high speed.

It also presents a way to seal and cut flexible polymer films with an indirect contact between the source of the heating system and the films, thus reducing contamination problems. As shown in Figure 1 a beam of laser beams 20 passes through the first jaw 30, referred to as an optical jaw, and which collides with the two layers of the tube that have been previously contacted by closing the jaws 30, 31 of the bra. The laser beam is partially or totally absorbed by the films in a volume referred to as the sealing volume and the absorbed energy heats the films causing the sealing process between the films. The films will be cut with sufficient energy absorbed in the sealing volume. By controlling the amount of energy absorbed by the films it is possible to seal and cut the flexible films in one operation. It is a feature of the present invention, as will be described later in this description, to present a method for controlling and optimizing the energy absorbed by the films. Typically the films have a thickness of less than 100 microns and contain a large proportion of polyethylene. In the manufacture of milk bags, the cross seals 14, 16 have a length of about 6 inches. Therefore the optical fastener needs to have a length of at least 6 inches to seal a sachet. The laser beam used in this preferred embodiment is a C02 laser beam, Which emits a wavelength of 10.6 microns less than 100 watts of energy. One skilled in the art will understand that another type of laser beam or a C02 laser beam emitting at another wavelength can also be used. The C02 laser beam is formed so that the desired intensity profile is obtained where the films should be sealed or sealed and cut. The C02 laser beam 20 can either be focused at a point about 1 mm in diameter 53 at the level of the films or can be formed, using an appropriate optical device, at an elongated point 58 that can cover the full width (6). inches) of the movies. In the first case, shown in Figure 12, the laser beam is scanned over the width of the films sealing in about half a second, the full width of the films. In the second case, shown in Figure 11, the laser beam formed at a horizontally elongated point, collides with the films for approximately half a second. In both cases the time exposure of the films can be controlled by a switch 57 which can interrupt the laser beam. Figure 2 illustrates the intensity profile of the laser spot on the surface of the films in the case of an elongated point 58: along the sealing length 17 and in the perpendicular direction 18. The lines of single grated 19 on the graph they show the extremities of the width of the films. The elongate bundle is generally longer than the width of the film so that the incoming intensity is large enough to seal the films and to ensure that the intensity along the sealing volume is not below an insufficient value. In the case where a laser point is circular, the distribution is the same in both axes and is similar to the distribution 18. By controlling the beam intensity profile by means of an appropriate beam formation, it is possible to control the distribution of the beam. the energy absorbed in the movies. In particular, an appropriate formation on the laser beam will provide, in one operation, two sealing regions separated by a region where the films are cut. This control of the distribution of absorbed energy is a feature of the present invention. The intensity absorbed by the films will depend on the intensity of shock and on the absorption capacity of the films. The type of films that are used to manufacture milk bags will typically absorb only about 10% of the intensity of the laser beams due to their thickness of only about 100 microns. Thicker films would naturally absorb more and films that have a special absorption layer could also absorb a larger portion of the beam of lasers that collide. However, it is a feature of the present invention to provide a way to increase the light absorbed by the films by allowing multiple passes of the laser beam to the films as will be discussed later in this description. The sealing and cutting process depends on many factors such as the amount of laser intensity that is absorbed, the distribution of the absorption of energy inside the films, the time exposure of the films and the thermal characteristics of the films such as the thermal conductivity of the films. In this preferred embodiment it was found that high quality seals were obtained by exposing the films to a total energy of less than 100 Joules per cm2. This corresponds in the case of a beam of lasers formed at an elongated point, at an exposure time of less than one second to produce two high quality seals throughout the entire width of the films that are separated by a region where movies have been cut. We will now describe in more detail numerous optical fastener drawings that can be used in this invention to seal and cut the films. Figure 3A illustrates the main parts of the fastener: the optical jaw 30 and the other jaw 31 can be moved by means of a mechanism 32 to a closed position as shown in Figure 3B for the purpose of bringing the two films 40 into contact with each other. 41 before the sealing process. The optical clamp is characterized by the fact that it has a window large enough to allow sealing in a single operation, of the full width of the movie. The laser beam 20 passes through that window to collide with the films as shown in Figure 5. The window may be the opening 37 in a metal structure as shown in Figure 3A, and may also be the opening covered by an optical material, it can be completely manufactured with a transparent material 38 or it could be a stage for a series of miniature lasers. The other jaw 31 may allow the reflection of the intensity of laser beams that were not absorbed in the first pass of the laser beams, back to the films thereby increasing the amount of laser light intensity available for the films. When the jaw 31 is designed to partially or totally reflect incoming laser light not absorbed, its metal surface may be a metallic polish. The jaw can also be configured 31 'as shown in Figure 6 to apply a tension on the films while they come into contact. Tension needs to be controlled in the case of thin plastic films to prevent stretching and thinning of the films before sealing or cutting. Figure 7A is an approximation of the sealing region of the films 39 showing the incident laser beam 20 passing through the two films, the intensity of non-absorbed laser beams then striking the contact jaw 31 'which is You have configured to reflect it back to the movies 21. Since the films absorb a small portion of the intensity of laser beams, this technique can ideally allow, approximately, to duplicate the laser light in the sealing volume, providing that the jaw 31 'has a high coefficient of reflectivity. The following three graphs show how the intensity of laser beams changes throughout their propagation in the films due to their absorption by the films. Figure 7B shows how the laser beam intensity is reduced during its propagation through the films in the first pass 71 and Figure 7C shows how the laser beam intensity is reduced in its return trip 72. After one pass, the intensity of laser beams has been reduced by an amount 83 and in a second pass by an amount 84. That amount absorbed by the films 73 as shown in Figure 7D and represents approximately twice the intensity of laser beams absorbed in a Single pass of laser beams. Figures 7E, 7F, 7G and 7H show what happens when the films have a high absorption layer 91 or 92. Due to the high absorption capacity of the layers, the intensity of laser beams is highly absorbed 79 at their level giving as a result a non-uniform absorption and therefore a non-uniform and localized heating of the films. In some cases a localized heating of the films may be a better approach than a uniform heating of the films. The optical fastener can also provide four passes of the laser beam 20 in the films. Figure 8A and 8B illustrate such a fastener. The optical clamp has a window that is profiled to reflect back the non-absorbed laser light to the films after the second pass of the laser beams. This modality provides an even greater efficiency in the sealing and laser cutting of polymeric films. Other configurations of the fastener jaws can allow multi-passes of the laser light through the films, as will be apparent to those skilled in the art. It will also be understood that the reflection process of the intensity of the non-absorbed laser beam can be provided by the use of reflection devices that are located externally to the window as shown in Figure 10 where a mirror is used 47 to reflect the unabsorbed light back to the movies. The optical fastener can also be used in combination with an air system to contact the films to be sealed. This is illustrated in Figure 9 where driven air currents 45 keep the films in contact during sealing by laser beams. The optical fastener can naturally be used with more than one laser beam device as illustrated in Figure 8B where two beams, 20 and 25 simultaneously seal and cut the films. This modality can add flexibility to the packaging system by enabling, for example, the control, separately, of the sealing and cutting process. The fastener can also be heated to assist the sealing and cutting process by providing a preheating of the films. All of the above possible optical fastener designs provide a more efficient way of sealing and cutting flexible polymer films or sheets as well as allowing indirect contact between the source of the heating system (laser source) and the films thereby reducing the problems of contamination. In addition all previous fastener designs allow to inspect the quality of the operation of sealing or cutting of the films while performing these operations. An example of a possible way of performing this quality monitoring is shown in Figure 14, where a beam splitter 101 is inserted between the laser beams 50 and the optical clamp 30, enabling optical inspection of the sealing quality while is being done An optical assembly 102 is used comprising a detector and focusing eyes to detect the intensity of the light emitted by the films being sealed. Therefore, some optical profile of the seal can be obtained and used to control the sealing and cutting process. The fasteners can allow a scan of a laser beam along the sealing volume or for an exposure of the films by an elongated laser beam. In both cases the fasteners allow to seal the full width of the film through its window. Figure 12 illustrates a possible scanning laser system wherein the laser beam 20 can be scanned along the sealing volume 53 by moving the mirror 52. Figure 11 illustrates the case where the full width of the laser is exposed. film to a luminous mark of elongated laser beams 58. The intensity of the laser beam is outlined by an optical device 56 in this luminous mark. One skilled in the art will appreciate that other forms of laser light marks can be generated and used to seal and cut the films. A special laser beam shapes can be obtained with appropriate optical devices. The intensity profile of the laser beam can be optimized by means of this profile method for stamp-cut-seal in a stage of exposure of the films and thus obtain two sealing regions where the films are sealed together separated by a cutting region where the films have been cut. The present invention can also be implemented for other packaging systems. Figures 13A, 13B and 13C are examples of other embodiments of this invention where an optical fastener is used in combination with a laser beam device to seal a package. Figure 13A shows a tube 85 filled with solid food which was sealed 86 by an optical fastener 30, 31. Figure 13C shows a bag being sealed by a laser device using an optical fastener. Figure 13B illustrates a food which was placed, in a first step, on a polymeric sheet 95 and which was then covered by another polymeric sheet 96. These films 95, 96 are sealed and cut with laser beams and a package is formed using an optical fastener. It will be understood that numerous modifications to the same will appear to those skilled in the art. According to the foregoing, the above description and the accompanying drawings should be taken as an illustrative of the invention and not with a limiting sense. Furthermore, it will be understood that it is intended to cover any variation, use or adaptation of the invention following, in general, the principles of the invention including such departures from the present description, as consequences of known or habitual practice within the technique to which it belongs. the invention and how they can be applied to the essential features included before being set forth and in the scope of the appended claims, as follows.

Claims (82)

1. CLAIMS 1. A fastener for overlaying and holding together at least two flexible polymer films while being optically sealed or cut by at least one laser beam, the fastener comprising: two jaws wherein at least one of said jaws can be moved to allow the closure and opening of the fastener, one of said jaws, being a contact jaw, to put the films in contact, the other jaw, being an optical jaw, has an optical window to let said, at least one, beam laser beams pass through it and wherein said window is wide enough to allow, if required, optically seal or cut the full width of said films, and support means to interconnect said jaws and allow controlled opening and closing. of the bra. The fastener as claimed in claim 1, wherein said optical window comprises an opening in a structure. The fastener as claimed in claim 1, wherein said optical window is made of a material transparent to the laser beam. 4. The fastener as claimed in claim 1, wherein said contact jaw has a profile for compressing said films together by either applying a pressure or tension on the films at the point of sealing and cutting. The fastener as claimed in claim 1, wherein said support means comprises an interconnection on at least one end of said jaws that leaves a gap between the jaws to allow the films to pass through. The fastener as claimed in claim 5, wherein said support means provides said opening to be large enough to allow a sachet with its contents to pass through. 7. The fastener as claimed in claim 1, wherein at least one of said jaws can be heated. The fastener as claimed in claim 1, wherein said contact jaw has a surface that partially or totally reflects the intensity of the laser beam that was not absorbed by the films and where it is profiled to reflect back towards the films the intensity of the laser beam not absorbed. The fastener as claimed in claim 8, wherein said optical jaw has a surface that partially or totally reflects the intensity of the laser beam that was not absorbed by the films and where said surface is profiled to reflect again towards the films the intensity of the laser beam not absorbed. The fastener as claimed in claim 9, wherein the surface of the jaws that are exposed to the intensity of laser beams not absorbed by the films, are profiled to allow a plurality of reflexes back and forth from a gag towards the other, thereby allowing multi-passes of the laser beam towards the films. The fastener as claimed in claim 9, wherein the surface of the jaws that are exposed to the intensity of laser beams not absorbed by the films, are profiled to allow three reflexes back and forth from a jaw towards the other, thus allowing four passes of the laser beam to the films. 12. A method for sealing or optically cutting with at least one beam of laser beams flexible polymer films, the method comprising: overlaying and contacting at least two of said films with each other, exposing an area of the films, the area corresponding to a sealing volume, at least one beam of lasers, providing an incident laser beam intensity, for the purpose of marking or cutting said films, increasing a laser beam intensity in the sealing volume by re-injecting partial or a totally unabsorbed portion of the intensity of the incident laser beam that was not absorbed by the films, again towards the films using at least one reflector device, thereby improving the efficiency of the sealing or cutting method by having more light intensity of said incident laser intensity absorbed by the films. The method as claimed in claim 12, wherein said optical seal or cut is a repetitive process step that is performed within a predetermined time duration only with the benefit of said re-injection of said intensity of lightning. laser not absorbed, back to the movies. The method as claimed in claim 12, wherein said unabsorbed laser beam intensity is at least 80% of said incident laser beam intensity. The method as claimed in claim 12, wherein said unabsorbed laser beam intensity is at least 85% of said incident laser beam intensity. The method as claimed in claim 12, wherein said unabsorbed laser beam intensity is at least 90% of said incident laser beam intensity. The method as claimed in claim 12, wherein said exposure of an area of the films comprises: focusing the laser beam on the films at a small point, scanning the small dot along the full width of the films. films to get an elongated seal, and control the scan to obtain a high quality stamp. 18. The method as claimed in claim 17, wherein said scan is continuous. The method as claimed in claim 17, wherein said scanning is performed using an optical system comprising at least one mirror to scan the spot of the laser beam on the films. The method as claimed in claim 12, wherein exposing the films comprises configuring the laser beam in a line wherein said line is sufficiently wide to cover the full width of the films to be sealed. The method as claimed in claim 12, wherein: said overlaying and contacting the films comprises activating two interconnecting clamps of a fastener to allow controlled opening and closing of the fastener to press the films between said clamps. jaws and releasing said films after sealing or cutting, said exposure of the films comprises directing said incident laser beam through a window in one of said jaws, and said re-injection of the unabsorbed laser intensity of new to the films comprises reflecting said intensity of non-absorbed laser beams, out of a reflective surface on another of said jaws. The method as claimed in claim 21, wherein said reflecting surface is profiled to reflect the intensity of unabsorbed laser beams, again towards the films in said volume with a distribution of intensity essentially equal to the intensity of laser beams. incident. 23. The method as claimed in claim 22, wherein the surface of the jaws that are exposed to the intensity of laser beams not absorbed by the films, are profiled to allow a plurality of reflexes back and forth from a gag towards the other, thus allowing multi-pass beam. laser beams towards the movies. 24. The method as claimed in claim 22, wherein the surface of the jaws that are exposed to the intensity of laser beams not absorbed by the films, are profiled to allow three reflections back and forth from one. gag towards the other, thus allowing four passes of the laser beam towards the films. 25. The method as claimed in claim 21 further comprising monitoring said sealing or cutting by inspection, using an optical detection assembly, of said area of the films through the optical window of the fastener, while the sealing or cutting is performed. 26. A method for optically sealing and cutting flexible polymer films with at least one laser beam having a configured intensity profile, the method comprising: configuring the at least one laser beam intensity profile. using an optical device to provide the desired intensity profile, superimposing and contacting at least two of said films with each other, and exposing an area of the films using appropriate optical elements, the area being referred to as a volume of stamp-cut-offs This, to said desired intensity profile with the purpose of obtaining, in an exposure stage, two sealed regions where the films are sealed together separated by a cutting region where the films have been cut and where for when the cutting region is made, the sealed regions are sealed. 27. The method as claimed in claim 26, wherein the intensity profile of the laser beam is a Gaussian profile. The method as claimed in claim 26, wherein each of said sealed regions is larger than said cutting region. 29. The method as claimed in claim 26, wherein said beam shaping comprises the use of a set of lenses and optical filters. 30. The method as claimed in claim 26, wherein said intensity profile of the laser beam comprises an intensity profile having a dimension at least greater than the width of said films for the purpose of covering the full width of the laser beam. the films to be sealed or cut. 31. The method as claimed in claim 26, wherein said configuration of the intensity profile of the laser beam comprises focusing the laser beam at a small point for the purpose of scanning said point along the seal volume. cut-seal of the movies. 32. The method as claimed in claim 26 further comprising monitoring said sealing and cutting by inspecting said sealing regions using an optical detection assembly. 33. The method as claimed in claim 32, wherein said optical detection assembly shares some of said optical elements. 34. A method for forming, sealing and optically cutting, and filling a sachet with a liquid at high speed, said method comprising the steps of: i) providing a vertical tube, made of a polymeric film that is partially or fully filled with a liquid or that is filled with a liquid; ii) flattening a filled section of said tube for a determined time interval using an optical sealing fastener for subsequent optical sealing and cutting of said section of said tube; iii) exposing said section of said tube to at least one laser beam intensity by a time exposure interval t, to heat said section of said tube in a controlled manner, said intensity being configured to obtain a desired intensity profile and to provide a corresponding absorbed intensity profile in said section of said tube; iv) providing a desired amount of heat to said section of said tube by optimizing a combination of said absorbed intensity profile, said time exposure interval and heating, if necessary, said optical sealing fastener; v) obtaining as a result two seals through said section of said tube and simultaneously cutting said tube between the seals, to form an upper seal for a filled sachet that is separated from said tube and a lower seal for said vertical tube. 35. The method as claimed in claim 34, wherein providing said vertical tube comprises the steps of: providing, in roll form, a polymeric film, stretching said film by means of stretching, on a tube former to form said vertical tube having an overlapping vertical film edge, sealing said vertical edge overlaid with a vertical sealant to form a vertical seal, continuously supplying a liquid within said tube below said vertical sealant and above said optical sealing fastener. 36. The method as claimed in claim 34, wherein said optical sealing fastener comprises: two jaws wherein at least one of said jaws can be moved to allow closure and opening of the fastener; one of said jaws being a contact jaw for contacting an internal wall of said section of said tube; the other jaw being an optical jaw having an optical window to allow said at least one intensity of the laser beam to pass therethrough, providing exposure of the section of the tube to the laser beam and wherein said the window is sufficiently wide to allow to optically seal or cut the complete width of said section of said tube; and support means for interconnecting said jaws and to allow a controlled opening and closing of the fastener. 37. The method as claimed in claim 36, wherein said optical window comprises an opening in a structure. 38. The method as claimed in claim 36, wherein said optical window is fabricated with a material transparent to the laser beam. 39. The method as claimed in claim 36, wherein said contact jaw has a profile for compressing said inner wall of said tube to each other by applying a pressure or tension on said tube at the point of sealing and cutting. 40. The method as claimed in claim 39, wherein said support means comprises an interconnection on at least one end of said jaws that leaves a gap between the jaws to allow the tube to pass therethrough and wherein said support means provides that said opening is sufficiently large to allow said filled sachet to pass through. 41. The method as claimed in claim 36 further comprising re-injecting, partially or totally, said laser beam intensity that was not absorbed in step iii) by means of a reflective property of said optical sealing fastener to increase in a controlled manner, the heat in said section of said tube. 42. The method as claimed in claim 41, wherein said contact jaw has a profiled surface that partially or totally reflects the intensity of the laser beam that was not absorbed in step iii) back into the tube. 43. The method as claimed in claim 42, wherein said optical jaw has a profiled surface that partially or totally reflects the intensity of the laser beam that was not absorbed back into the tube. 44. The method as claimed in claim 43, wherein the surface of the jaws is profiled to allow a plurality of reflections from back to front from one jaw to the other, thereby allowing multi-passes of the beam intensity of lasers towards the movies. 45. The method as claimed in claim 43, wherein the surface of the jaws is profiled to allow three reflections from back to front from one jaw to the other, thereby allowing four passes of intensity of the laser beam towards the movies . 46. The method as claimed in claim 34, wherein said exposure comprises: focusing the intensity of the laser beam on said section of said tube at a small point; scanning the small dot along the full width of said section of said tube to obtain an elongated seal; and control the scan to obtain a high quality seal. 47. The method as claimed in claim 46, wherein said scan is continuous in time. 48. The method as claimed in claim 46, wherein said scanning is performed using an optical system comprising at least one mirror for scanning the spot of the laser beam on the films. 49. The method as claimed in claim 34, wherein said exposing said section of said tube comprises configuring the laser beam in a line wherein said line is broad enough to cover the entire width of the tube section. to be sealed 50. The method as claimed in claim 34, wherein the desired intensity profile is a Gaussian profile. 51. The method as claimed in claim 34, wherein said beam intensity is configured using a set of lenses and optical filters. 52. The method as claimed in claim 34, wherein said desired intensity profile comprises an intensity profile having a dimension at least larger than the width of said tube for the purpose of covering the full width of the tube to be sealed. and cut yourself. 53. The method as claimed in claim 36 further comprising monitoring said sealing and cutting while said seals are being made by inspecting, using an optical detection assembly, said section of said tube through the optical window of the Optical sealing fastener. 54. A method for sealing or sealing-and-cutting packages made of polymeric films using at least one laser source and at least one optical sealing fastener, the method comprising the steps of: i) providing a package partially or completely formed that is partially or completely filled with its content or that is being filled with its content; ii) overlapping and contacting an internal wall of a section of said package for a subsequent seal by means of an optical sealing fastener; iii) exposing said section of said package to at least one intensity of the laser beam, for a time exposure interval t, to heat said section of said package in a controlled manner, said intensity being formed to obtain an intensity profile desired and to provide a corresponding absorbed intensity profile in said section of said package; iv) providing a desired amount of heat to said section of said package for the purpose of performing either a sealing operation or a sealing-and-cutting operation, optimizing a combination of said absorbed intensity profile, said exposure range of time and heating, if necessary, said optical sealing fastener; v) obtaining as a result in the case of a sealing operation, a seal through said section of said package and in the case of a sealing-and-cutting operation, two stamps through said section of said package and simultaneously a cutting region between the two seals where the package is cut. 55. The method as claimed in claim 54, wherein step i) comprises: providing, in the form of a roll, two sheets of polymeric films, stretching one of said sheets of film over a packaging station where the film is deposited. content of the package on the film, stretch the second sheet of film on said content to form said partially formed package. 56. The method as claimed in claim 54, wherein step i) comprises providing a tube made of a polymeric film. 57. The method as claimed in claim 54, wherein step i) comprises providing a bag made of a polymeric film. 58. The method as claimed in claim 54, wherein said optical sealing fastener comprises: two jaws wherein at least one of said jaws can be moved to allow closure and opening of the fastener; one of said jaws being a contact jaw for contacting said inner wall of said section of said package; the other jaw being an optical jaw having an optical window to allow said at least one intensity of the laser beam to pass therethrough, providing exposure of the package section to the laser beam and wherein said The window is sufficiently wide to allow to optically seal or cut the complete width of said section of said package; and support means for interconnecting said jaws and to allow a controlled opening and closing of the fastener. 59. The method as claimed in claim 58, wherein said optical window comprises an opening in a structure. 60. The method as claimed in claim 58, wherein said optical window is fabricated with a material transparent to the laser beam. 61. The method as claimed in claim 58, wherein said contact jaw has a profile for compressing said internal wall of said package together by applying a pressure or tension on said package at the point of sealing and cutting. 62. The method as claimed in claim 61, wherein said support means comprises an interconnection on at least one end of said jaws that leaves a gap between the jaws to allow the package to pass through them and in wherein said support means provides that said opening is large enough to allow said filled pack to pass through. 63. The method as claimed in claim 58 further comprising re-injecting, partially or totally, said laser beam intensity that was not absorbed in step iii) by means of a reflective property of said optical sealing fastener to increase in a controlled manner, the heat in said section of said package. 64. The method as claimed in claim 63, wherein said contact jaw has a profiled surface that partially or totally reflects the intensity of the laser beam that was not absorbed in step iii) back to the package. 65. The method as claimed in claim 64, wherein said optical jaw has a profiled surface that partially or totally reflects the intensity of the laser beam that was not absorbed by the package back to the package. as claimed in claim 65, wherein the surface of the jaws are profiled to allow a plurality of reflections from back to front from one jaw to the other, thus allowing multi-passes of the intensity of the laser beam. 67. The method as claimed in claim 65, wherein the surface of the jaws is profiled to allow three reflections back and forth from one jaw to the other, thus allowing four passes of intensity of the jaw. beam of lasers towards the films 68. The method as claimed in claim 54, wherein said exposure comprises: focusing on said section. of said section of said package the intensity of the laser beam at a small point; scanning the small dot along the full width of said section of said package to obtain an elongated seal; and control the speed of the scan to obtain a high quality seal. 69. The method as claimed in claim 68, wherein said scan is continuous in time. 70. The method as claimed in claim 68, wherein said scanning is performed using an optical system comprising at least one mirror for scanning the spot of the laser beam on the films. . 71. The method as claimed in claim 54, wherein said exposure of said section of said package comprises configuring the laser beam in a line wherein said line is sufficiently wide to cover the complete width of the package section. to be sealed 72. The method as claimed in claim 54, wherein the desired intensity profile is a Gaussian profile. 73. The method as claimed in claim 54, wherein said intensity of the beam being configured is made using a set of lenses and optical filters. 74. The method as claimed in claim 54, wherein said desired intensity profile comprises an intensity profile having a dimension at least larger than the width of said package for the purpose of covering the full width of the package to be sealed and cut yourself. 75. The method as claimed in claim 58 further comprising monitoring said sealing or sealing-and-cutting operation by inspection using an optical detection assembly of said section of said package through the optical window of a fastener. of optical sealing while the sealing or sealing-and-cutting operation is carried out. 76. A laser welding system for sealing or cutting polymer sheets, the system comprises: a laser source that supplies a laser beam; means for projecting the laser beam onto a region of said polymer sheets where said sealing or cutting will be made; an optical device for representing in image the sealing or cutting while performing; an image analyzer to ensure said quality of sealing or cutting; an integrated control means for controlling said laser beam source, said means for projecting said optical device and said image analyzer. 77. The system as claimed in claim 76, wherein said optical device comprises a camera. 78. The system as claimed in claim 76, wherein said optical device shares some elements with said laser beam. 79. A fastener for overlaying and holding together at least two polymer sheets while being optically sealed or cut by at least one laser beam, the fastener comprising: two jaws wherein at least one of said jaws can be moved to allow closure and the opening of the fastener, one of said jaws being a contact jaw for contacting the blades, the other jaw being an optical jaw having an optical window to allow said at least one laser beam to pass through. through them and wherein said window is wide enough to allow, if necessary, to seal or optically cut the full width of said sheets; and support means for interconnecting said jaws and to allow a controlled opening and closing of the fastener. 80. A method for optically sealing or cutting with at least one laser beam, polymeric sheets, the method comprising: superposing and contacting at least two of said sheets with each other, exposing an area of the sheets, the corresponding area to the sealing volume, to the at least one laser beam, providing an incident laser beam intensity, for the purpose of sealing or cutting said blades, increasing a laser beam intensity in the sealing volume by re-injecting partial or a totally unabsorbed portion of the intensity of the laser beam that was not absorbed by the sheets, back to the sheets using at least one reflector device, thereby improving the efficiency of the sealing or cutting method by having more light intensity said intensity of incident laser rays absorbed by the leaves. 81. A method for optically sealing and cutting polymer sheets with at least one laser beam having a configured intensity profile, the method comprising: configuring the at least one intensity profile of the laser beam using an optical device to provide the desired intensity profile, superimposing and contacting at least two of said sheets with each other, and exposing an area of the sheets using appropriate optical elements, the area being referred to as a stamp-cut-seal volume, to said desired intensity profile for the purpose of obtaining in an exposure stage, two sealing regions wherein the sheets are sealed together, separated by a cutting region. where the leaves have been cut and where by the time the cutting region is made, the sealing regions are sealed. 82. A method for sealing or sealing-and-cutting packages made with polymeric sheets using at least one laser source and at least one optical sealing fastener, the method comprising the steps of: i) providing a partially or fully formed package that is partially or completely filled with its content or that is being filled with its content; ii) overlapping and contacting an internal wall of a section of said package for a subsequent seal by means of an optical sealing fastener; iii) exposing said section of said package to at least one intensity of the laser beam, for a time exposure interval t, to heat said section of said package in a controlled manner, said intensity being formed to obtain an intensity profile desired and to provide a corresponding absorbed intensity profile in said section of said package; iv) providing a desired amount of heat to said section of said package for the purpose of performing either a sealing operation or a sealing-and-cutting operation, optimizing a combination of said absorbed intensity profile, said exposure range of time and heating, if necessary, said optical sealing fastener; v) obtaining as a result in the case of a sealing operation, a seal through said section of said package and in the case of a sealing-and-cutting operation, two stamps through said section of said package and simultaneously a cutting region between the two seals where the package is cut.