FR3075766A1 - METHOD AND MACHINE FOR MANUFACTURING PACKAGES, PACKAGES OBTAINED - Google Patents

Abstract

The invention relates to a process for the manufacture of packaging, the container of which is made from a pre-cut and pre-grooved flat cardboard sheet, each container being made up in 3 dimensions with a bottom and side walls by folding, the interior of the volume of the container then being coated with a plasticized film by thermoforming. The method comprises: - the automated loading at a predetermined rate of the sheets into at least one thermoforming mold cavity; - the thermoforming of the film in the containers at a rate synchronized with the rate of loading. The packages of the invention are obtained by machines essentially comprising loading and thermoforming stages.

Description

Method and machine for manufacturing packaging, packaging obtained.

The present invention is in the field of packaging, and more specifically in that of packaging whose containers are cardboard, but which require sealing, obtained by subsequent thermoforming of a plastic film inside the container.

The problem that arises in reality is the automation of the production of such packaging at sustained rates, which are capable of actually impacting the machines, the production processes, or even the final products, that is to say the packaging itself. The heart of these machines is made up of a thermoforming unit which performs temperature forming of the film, in other words gives it a hot shape to adapt it to the volumes of cardboard containers themselves preformed and deposited. prior to forming the film in the mold in order to constitute the packaging.

In practice, feeding the thermoforming unit with cardboard boxes leads to a fairly significant reduction in production rates, due to the need to process these sheets before thermoforming. The present invention aims to optimize these rates by proposing a global design aiming to synchronize the two main functional chains respectively of container supply and thermoforming, reviewed in the perspective of this optimization.

Thus, according to the invention, the method of manufacturing packaging, which relates to packaging, the container of which is produced from a cardboard sheet (cardboard of any type) flat, pre-cut and pre-cleaned, each container being made up in 3 dimensions with bottom and side walls by folding, the interior of the volume of the container then being coated with a film plasticized by thermoforming, is essentially provided as it comprises:

- Automated loading at a predetermined rate of the sheets in at least one thermoforming mold imprint;

- the thermoforming of the film in the containers at a rate synchronized with the loading rate.

This loading requires a shape transformation, a transition from a two-dimensional state to a three-dimensional state of the pre-cut and pre-perforated cardboard sheet, or even perforated if necessary, using successive steps strictly mechanical which results in practice in the limitation of permitted rates.

In fact, more precisely, automated loading includes:

- The taking of at least one flat sheet precut and pre-cleaned by means for recovering the sheets from at least one stack of said sheets, and the immobilization of the sheets on said recovery means;

- A transfer of each sheet to supply means of at least one thermoforming mold imprint, and the immobilization and preforming of the sheets in said supply means.

It is obviously essential that during each step finally leading to the filling of the thermoforming molds, the positioning of the cardboard sheets is guaranteed with precision.

According to a possible configuration, the transfer of each sheet is carried out by activation of mobile mechanical or robotic intermediate transfer means in coordination with the respective movements of the recovery means and of the supply means, said transfer means also being provided with means gripping / immobilization of each sheet.

In fact, according to a possible kinematics, the recovery means move between two positions respectively of gripping at least one sheet from a stack and transfer, the transfer means are movable between a position for taking each sheet cardboard from the recovery means and a transfer position, and feed move between a reception of each sheet from the position means of transfer means and a position for feeding a mold impression of thermoforming.

These movements, which involve the same journey in two opposite directions, are preferably carried out at least partially simultaneously, in order to optimize the feed rates and not to interfere with the overall treatment time.

The method also comprises a preforming of the cardboard sheets by correspondence of dimensions and orientation of surfaces on the one hand of the gripping / immobilization means in the supply means and on the other hand in the imprint of the thermoforming mold, allowing then a volume match during mutual insertion.

Preferably, the respective surfaces of the cavities and of the supply means corresponding respectively to the bottom and to the side walls of the packaging can be matched and kept in contact sequentially, by suction obtained by generation of a depression at predetermined locations. of the walls of the footprint.

This can in particular be achieved by decoupling these zones in the supply means, by giving them a degree of freedom relative to the other controlled by return means, as will be seen more in detail. detail below. Separate contact holding means exist in these two zones, hence the possibility of separate and sequential implementation, for example by suction.

According to the invention, still in an overall rate optimization, supplying by packaging at least one mold cavity and a step of thermoforming another preformed inserted in a cavity are almost simultaneously, a tilting mold comprising on its circumference at least one mold imprint being driven sequentially according to at least two distinct rotary positions, said positions defining an operating time step.

The film is continuous and moved in successive steps, this time dimensional, between storage means, at the entrance to the machine, and a thermoforming stage, at least one heating step placed upstream of the thermoforming stage on along a dimensional step being activated continuously. This heating aims to prepare and optimize the thermoforming which induces a deformation of the plastic film helped by a perspective a packaging step carried out softening of the plastic. In the context of the process of the invention, the film chosen has a thickness much less than that of the films usually used, which consequently has a thermal inertia also less than these. It therefore cools quickly and, due to the existence of at least one vacuum step to allow adaptation to the different mold sizes, (see below), it may no longer be hot enough to be thermoformed in good conditions.

In this case, the method may include two heating steps, including an optional step operating at a dimensional step when empty, if necessary, that is to say if the mold sizes require it.

A heating of the imprints receiving the preformed packaging is more preferably carried out, in order to activate an adhesive layer which the film has, an additional layer which has the function of achieving a complete joining of the film in the cardboard. This joining plays a role in the mechanical strength of the assembly, due to a withdrawal effect on the internal walls of the packaging. The withdrawal effect makes it possible, for example, to urge the folded peripheral skirts or edges which may be provided with the packaging to give them a potentially interesting elastic effect. Cover is provided, to ensure its elastic fixing by clipping to the packaging.

The packages concerned by the process obviously do not necessarily include such folded peripheral skirts, which are generally the prerogative of packages with separate cover. The method also applies to packages sealed with a reminder when sealing a film on the peripheral edges, according to the example given below.

To optimize the laying of the film against the interior faces of the walls and of the bottom of the container, the method includes the generation of a vacuum during the thermoforming of the film, in connection with the position of the orifices made in the container. In practice, the holes in the impressions through which the pressure difference is applied to the packaging can be positioned in the vicinity of the holes in the container, for example the lines pierced with dotted lines, or the holes for fixing a cover in the flanges, etc. , if a cover is provided.

A cutting peripheral of the containers can to be expected after 1'opération of thermoforming, is directly in periphery of mold, according to a

integrated configuration, either separately.

The packaging produced by this process, at an optimum rate therefore relative to the constraints, in particular mechanical supply of cardboard, is in particular based on a thermoformable film, mono material or complex, having a thickness for example between 80 μιη and 200 μιη , that is to say significantly less than in the conventional thermoforming processes applied to this context, as previously emphasized. The film used, designed to match the interior faces of the cardboard boxes and give them an aesthetically very accomplished appearance, with in particular a possibility of preserving the walls at sharp angles, comprises on one of its faces a layer of hot-activatable adhesive activated by the specific heating means for the molds mentioned above.

According to a possible configuration, the packaging of the invention further comprises peripheral flanges extending each side wall and foldable outwards towards them. It is this outward fold which is thwarted by the shrinkage of the film, and produces the opposite elastic force which has been mentioned.

In fact, the adjacent ends of said flanges are not in contact with each other and are connected by a portion of film provided with a diagonal fold, which results from the cut applied after thermoforming, the fold itself being obtained by mold imprints during thermoforming. Said diagonal fold is oriented, following molding, so that the portion of film between the edges can become practically invisible when the latter are folded towards the side walls, if the fold is oriented downwards. This version corresponds, for example, to packaging with a separate cover. Alternatively, the adjacent ends of the flanges can be abutted, said flanges then forming a continuous peripheral border. Such a version is for example used when the packaging is closed by a cover made of heat-sealed plastic film on said peripheral edge, which is then preferably flat or substantially flat.

The cardboard for making the container is preferably chosen to be porous, so as to facilitate the suction of the film in contact with the internal faces of said container during the suction phases. The fold lines of the pre-cut cardboard sheets for the production of the container also include dotted perforated lines and incised half-flesh lines which aid in folding, in particular during the preforming and forming phases in the mold cavities. . Thus, for example, it is the lines which delimit the bottom of the container which can be pierced with dashed lines.

The flanges can moreover comprise at least one orifice for fixing a cover, the portion of film which covers each orifice, like all the rest of the container on one side, then being shaped as a bubble projecting towards the side walls of the container, so as not to oppose the insertion of a lug protruding from the cover, if applicable. These bubbles are obtained during the thermoforming phase, by suction of the film through the orifices, which is produced by the existence of a depression at least in certain places of the walls of the imprint. This vacuum can also be applied locally targeted, depending on the positioning of the mold orifices conveying the vacuum.

The machine for producing the packaging described above, which allows the implementation of the process with a view to the automated manufacture of these packaging at optimized rates, essentially comprises:

- an automated loading robot for feeding and preforming cardboard containers, a thermoforming unit thermoforming the film in the preformed container.

It is these two sets, managing specific chains requiring very different approaches, that should be synchronized in order to synchronize their technical techniques to interface operation.

Thus, for example, the automated loading robot includes:

- means for recovering the sheets from at least one stack of said sheets, said recovery means being provided with means for gripping / immobilizing the sheets;

- means of transferring each sheet to:

means for feeding the thermoforming unit comprising means for gripping / immobilizing the sheets and preforming means provided for cooperating with each imprint of the mold or molds of the thermoforming unit.

This structure and this kinematics for loading cardboard boxes are in particular adapted to the operation of the thermoforming unit, and respects practical considerations of interconnection with it. Due to the already mentioned need to guarantee the

position of each sheet during of each of the phases of their transfer to the steps of preforming / loading / thermoforming, the means of

mobile transfers are also provided with means for gripping / immobilizing each sheet.

In fact, more precisely, the recovery means comprise at least one sheet recovery tray, the transfer means comprise at least one sheet transfer plate and the means comprise at least one sheet plate, in equal number, these structures flat in appearance being suitable for conveying two-dimensional cardboard sheets to be transformed into three-dimensional cardboard boxes. More precisely still, the recovery means, the transfer supply power means, the supply means respectively comprise a number of recovery plates, transfer plates and supply plates equal to the number of stacks of leaves.

According to a preferred configuration, the means for gripping / immobilizing the sheets on each recovery tray respectively, each mobile transfer and supply plate consist of constitute a solution adapted to each suction cup plate, which both to immobilize and to fix to the when the leaves were taken from their previous location in the chain.

Each feed plate furthermore has a relief shape having inclined borders surrounding a central zone, said central zone and said borders being dimensioned according to the creases and cutouts of the sheets, in negative of the recess of the imprint of the corresponding molds. , and playing a role in the preforming of the boxes before thermoforming. Preferably, the central zone of the relief shape is retractable against springs, with a view to implementing the sequential plating of the cardboard precuts at the bottom of the imprints. Thus, initially, the bottom of the cardboard is pressed against the bottom of the imprints by said central zone, while the walls of said cardboard are still free from any plating pressure. Then, in a second step, when the central zone flows back against the springs under the effect of the displacement of the feed plates towards the cavities, the inclined edges of said plates in turn press the side walls of the cardboard boxes against the inclined walls of footprints.

To maintain said walls and the bottom of the packages inside the molds when the supply means are withdrawn, the bottom of the imprints has orifices connected to first means for generating a depression and the inclined edges of the imprints include orifices connected to second means for generating a depression. These orifices linked to means for generating a vacuum are, as mentioned above, placed in such a way that they can also help during the thermoforming operation, to press the film being thermoformed against the inner face of the containers.

The mold cavities are, in a possible configuration particularly suitable for increasing production rates, performed in a tilting mold, that is to say a rotary mold between two positions which is used, in the machine of the invention, not only for thermoforming the films in the cardboard boxes and evacuating the packaging thus obtained, but also for loading the molds in connection with the loading robot. This characteristic can be seen as constituting an appreciable factor in optimizing the automation of packaging manufacturing.

All this concerns the supply of the cardboard element of the packaging, which is however carried out in parallel and in masked time with the supply of plastic film, which constitutes in a way the second source of supply, to be managed at the same time. that and in sync with the first one.

The machine of the invention comprises, for the purpose of continuous supply of plastic film, a film drive stage consisting of pin chains located at the two lateral edges of the film, a roller made of elastomeric material being placed on each side. at the incoming arrivals of the continuous film, which is for example stored on a roller allowing the successive unwinding of a certain quantity of film, in dimensional steps compatible with the automation process. In the invention, it has been seen that the film is particularly thin and that it comprises a layer of adhesive material, these specific characteristics having consequences on its processing in the machine.

Thus, as it is more flexible than the films usually used for thermoforming operations, a spike drive proves, as such, inadequate because the spikes do not pass through the film. This is the reason why a roller is added at the inlet, at the level of which the perforation takes place, allowing the downstream drive. The film is wedged between the rollers and the pins, allowing drilling because of the bearing surface on which the film rests.

According to another possible configuration, the machine of the invention comprises, for the purpose of continuous supply of plastic film, a film drive stage consisting of chains with clips located at the two lateral edges of the film.

The machine further includes an additional heating unit placed immediately upstream of the thermoforming stage. This also results from the special nature of the film. In a thermoforming unit, the film is advanced in successive steps. It is usual to position a heating device (for example infrared) above and below a portion of film corresponding to a dimensional step.

This heated portion then advances by one step to be replaced by another. All movements are therefore multiples of an integer number of steps, and depend in particular on the dimensions of the thermoforming mold.

The heating stage precedes thermoforming. The thermoforming mold has a part mounted on a holding structure, in this case for example a tilting mold, and a mobile part mounted on another structure which translates to the first structures are larger than molds, to allow to adapt different sizes of molds. It is therefore necessary to provide at least one intermediate vacuum step between the heating stage and the thermoforming stage.

For usual film thicknesses, this does not pose any particular problem, but in the case of a thin film like that used in the invention, we have seen that the thermal inertia of the material is very low, that it does not can therefore accept that an empty step beyond, the film cools and it can no longer be thermoformed.

To compensate for the difference between the standard heating stage and the thermoforming stage, in the machine of the invention, an additional removable heating unit has been added, making it possible to reduce the number of no-load steps as much as possible .

Another consequence of the particular films used imprint of the mold includes its own thermoregulated heating means. These generate a suitable mold temperature whereas in principle, with usual films of thickness provided between 200 μιη and 800 μπι, an unheated mold is used, which allows to freeze more

These the and

At the characteristics is that each matter quickly. But in the invention, it is necessary to activate the adhesive layer intended to fix the film, and which consequently interfaces between the plastic film and the cardboard, by transferring - at the time of thermoforming - heat through the cardboard.

The machine of the invention preferably also includes means for peripheral cutting of the containers, said cutting means acting on the periphery of the mold cavities or being actuated separately. In the latter case, it may be a conventional cutting by punch / die, dissociated from the rest making it possible to simplify the tooling, therefore to lower the costs, to increase the rates, and, the film being already secured to the cardboard, allowing a perfectly concentric cut.

The invention will now be described in more detail, with reference to the appended figures which represent nonlimiting examples of packaging according to the invention, and for which:

- Figure 1 shows in elevational view a blank of perforated cardboard cut and creased so as to allow preforming of the cardboard;

- Figure 2 shows, in perspective view, the final packaging, formed and coated with a plastic film;

- Figure 3 shows, in perspective view similar to Figure 2, the packaging with the flaps folded towards the side walls of the container;

FIG. 4 illustrates the packaging of the invention provided with a cover clipped onto its edges;

- Figure 5 shows an enlarged detail, in sectional view, of the method of fixing the cover on the packaging.

- Figure 6 is an elevational plan view of an alternative packaging intended to be closed by a heat-sealed film; and

- Figure 7 shows the packaging of Figure 6 in perspective view.

With reference to FIG. 1, the blank 1 comprises a central zone constituting the bottom 2 of the cardboard box, and trapezoidal lateral zones 3, 4, 5, 6 delimiting the lateral walls of the container. These walls 3 to 6 are extended by flanges 7 to 10, from which they are separated by grooves il, il 'obtained by mid-flesh incision. The edges 12, 12 'of separation between the bottom 2 and the side walls 3 to 6 are incised in dotted lines, so as to constitute orifices used during the suction phases for example to help press the plastic film against the faces inside the container. According to a possible configuration, the flanges 7 to 10 each have holes 13, 14 provided for fixing a cover as shown in Figures 4 and 5. All these incisions, through or half-flesh, of course help fold the panels, for preforming or forming the cardboard.

When the filming is carried out, under the conditions seen above, the film, in addition to covering the interior faces of the bottom 2 and the side walls 3 to 6, as well as the upper faces of the flanges in the extension of the others, has portions angle 15 between the flanges 7 to 10, as shown in FIG. 2, giving the packaging a continuous peripheral skirt. These film portions 15 are shaped with a diagonal pleat 16, obtained as mentioned previously during molding in the thermoforming phase. This fold allows natural folding in one direction (down) or the other (up). In the representation of Figure 3, the corner portion 15 is folded down, and therefore becomes invisible. During thermoforming, the flanges 7 to 10 are over-opened, to compensate for the shrinkage effect of the film, in a position which is for example that of FIG. 3, resulting moreover in the mechanical effect of return towards the outside of the edges, mentioned previously and which facilitates the mechanical clipping of the cover 17 (see in FIGS. 4 and 5). The peripheral skirt formed by the edges 7 to 10 connected by the corner portions 15 of the film is subject to a cutting operation after thermoforming, which obeys the constraints of punch / die cutting systems.

When a cover 17, for example made of transparent plastic, is fixed on the container, lugs 18 projecting towards the inside of the peripheral skirt 19 of said cover 17 are provided at the orifices 13, 14 formed in the flanges 7 to 10 The relative rigidity of the cover combined with the spring effect applying to the flanges 7 to 10, naturally stressed outwards and upwards, results in a mechanical closing connection which is firm and pleasant to use. When inserting the cover 17, the flanges 7 to 10 are pushed towards the side walls 3 to 6 of the container until the lugs 18 arrive opposite the orifices 13, 14, which allows the clipping. The reverse operation is simple to implement to remove the cover 17.

In the alternative configuration of FIGS. 6 and 7, the initial cutting of the blank 1, a little different, is such that the axial ends of the flanges 7 to 10 adjust to each other during a planar abutment, forming a peripheral flange continuous appearance parallel to the bottom 2 on which a film-coated cover (not shown) can be heat-sealed. For reasons of clarity, the same references as in the previous configuration are used for the same parts of the packaging. The angle of the cutouts at said axial ends of the flanges 7 to 10 is therefore provided such that the continuous abutment can take place as shown in FIG. 7, which also shows the thermoformed film internally, in light gray, on all of the faces. internal and almost all the edges 7 to 10 (for illustrative reasons, to better understand its positioning relative to the container: in reality, it also covers all the edges 7 to 10).

The sealing is carried out on a surface of planar appearance which is consequently shaped into a rectangular crown, and materialized by the flanges 7 to 10 following each other continuously. The manufacturing process of the invention applies in the same way to the production of the containers thus produced as to the manufacturing of the packaging described with reference to using the same machine.

5, figures 1 fabrication.

The invention is of course not limited to the examples described and explained with reference to the figures, but it encompasses the variants and versions which fall within the scope of the claims.

Claims (31)

1 * Method of manufacturing packaging, the container of which is produced from a sheet 1 of pre-cut and pre-cut flat cardboard, each container being made up in 3 dimensions with bottom 2 and side walls 3, 4, 5, 6 by folding, the interior of the container volume then being coated with a plastic film by thermoforming, characterized in that it comprises: - Automated loading at a predetermined rate of the sheets 1 in at least one thermoforming mold imprint; - the thermoforming of the film in the containers at a rate synchronized with the loading rate. 2. Method of manufacturing packaging according to the preceding claim, characterized in that the automated loading comprises: - Taking at least one flat sheet 1 precut and pre-cut by means for recovering the sheets from at least one stack of said sheets 1, and immobilizing the sheets 1 on said recovery means; - A transfer of each sheet 1 to supply means of at least one thermoforming mold imprint, and the immobilization and preforming of the sheets 1 in said supply means. 3, A method of manufacturing packaging according to the preceding claim, characterized in that the transfer of each sheet 1 is effected by activation of mobile intermediate transfer means in coordination with the respective movements of the recovery means and supply means , said transfer means being provided with means for gripping / immobilizing each sheet 1. 4, A method of manufacturing packaging according to the preceding claim, characterized in that the recovery means move between two positions respectively of gripping at least one sheet 1 from a stack and transfer, the transfer means are movable between a position for taking each sheet 1 from the recovery means and a transfer position, and the supply means move between a position for receiving each sheet 1 from the transfer means and a supply position a thermoforming mold imprint. 5. Method of manufacturing packaging according to one of claims 2 to 4, characterized by a preforming of the sheets 1 by correspondence of dimensions and orientation of surfaces on the one hand of the gripping / immobilization means in the means of feed and on the other hand in the mold of the thermoforming mold, then allowing a volume match during mutual insertion. 6, A method of manufacturing packaging according to the preceding claim, characterized in that the respective surfaces of the imprints and the supply means corresponding respectively to the bottom 2 and to the side walls 3, 4, 5, 6 of the packaging are put in correspondence and maintained in contact sequentially by aspiration obtained by generation of a depression at predetermined locations of the walls of the imprint. 7. A method of manufacturing packaging according to one of the preceding claims, characterized in that a step of feeding by packaging at least one 10. 11. 12, mold imprint and a step of thermoforming of another preformed packaging inserted into an imprint are carried out almost simultaneously, a tilting mold comprising on its circumference at least one mold imprint being driven sequentially according to at least two distinct rotary positions, said said positions defining an operating time step. Method of manufacturing packaging according to one of the preceding claims, characterized in that the film is continuous and moved in successive dimensional steps between storage means and a thermoforming stage, at least one heating step placed upstream of the thermoforming stage along a dimensional pitch being activated continuously. Method of manufacturing packaging according to one of the preceding claims, characterized in that it comprises two heating stages, including an optional stage operating at the level an empty dimensional step. Method of manufacturing packaging according to one of the preceding claims, characterized by heating the cavities receiving the preformed packaging. Method of manufacturing packaging according to one of the preceding claims, characterized by the generation of a vacuum during the thermoforming of the film, in connection with the position of the orifices made in the container. Method of manufacturing packaging according to one of the preceding claims, characterized by a peripheral cutting of the containers after thermoforming. Cardboard packaging forming the container coated with an internal plastic film obtained by the process of claims 1 to 12, characterized in that the thermoformable film has a thickness of between 80 µm and 200 µm. 14. Packaging according to the preceding claim, characterized in that the film comprises on one of its faces a layer of hot-activatable adhesive. 15. Packaging according to one of claims 13 and 14, characterized in that it has peripheral flanges 7, 8, 9, 10 extending each side wall 3, 4, 5, 6 and foldable outwards towards them- this. 16. Packaging according to claims 15, characterized in that the adjacent ends of the flanges 7, 8, 9, 10 are not in contact with one another and are connected by a portion of film 15 provided with a diagonal fold 16 . 17. Packaging according to claim 15, characterized in that the adjacent ends of the flanges 7, 8, 9, 10 are abutted, said flanges 7, 8, 9, 10 forming a continuous peripheral border. 18. Packaging according to one of claims 13 to 17, characterized in that the cardboard for the realization of the container is porous. 19. Packaging according to one of claims 13 to 18, characterized in that the fold lines of the cardboard sheets precut for the realization of the container comprise lines pierced in dotted lines and incised lines half-flesh. 20. Packaging according to one of claims 15 to 19, characterized in that the flanges 7, 8, 9, 10 comprise at least one orifice 13, 14 for fixing a cover 17, the portion of film which covers each orifice 13, 14 being shaped as a bubble projecting towards the side walls 3, 4, 5, 6 of the container. 21. A packaging manufacturing machine according to claims 13 to 20, the container of which is produced from a sheet 1 of pre-cut and pre-cut flat cardboard, each container being preformed in 3 dimensions by folding, the interior of the volume of the container. then being coated with a plastic film by thermoforming, characterized in that it comprises: - an automated loading robot for feeding and preforming cardboard containers; - a thermoforming unit thermoforming the film in the preformed container. 22. Packaging manufacturing machine according to the preceding claim, characterized in that the automated loading robot comprises: - means for recovering sheets 1 from at least one stack of said sheets 1, said recovery means being provided with means for gripping / immobilizing sheets 1; - means for transferring each sheet 1 to: means for feeding the thermoforming unit comprising gripping / immobilizing the preforming means provided for each imprint of the mold or molds of the thermoforming unit. 23. Machine for manufacturing packaging according to the preceding claim, characterized in that the mobile transfer means are provided with means for gripping / immobilizing each sheet 1. of sheet means 1 and to cooperate with 24. Packaging manufacturing machine according to one of claims 22 and 23, characterized in that the recovery means comprise at least one sheet recovery tray 1, the transfer means comprise at least one sheet transfer plate 1 and the supply means comprise at least one plate supplying the sheets 1, in equal number. 25. Machine for manufacturing packaging according to the preceding claim, characterized in that the recovery means, the transfer means, the supply means respectively comprise a number of recovery trays, transfer plates and plates of feed equal to the number of stacks of sheets 1, 26. Machine for manufacturing packaging according to one of claims 24 and 25, characterized in that the means for gripping / immobilizing the sheets 1 on each recovery tray respectively, each movable transfer plate and each feed plate consist of suction cups. 27. Machine for manufacturing packaging according to one of claims 24 to 26, characterized in that each feed plate comprises a relief shape having inclined edges surrounding a central area, said central area and said edges being dimensioned according to creasing and cutting of the sheets 1, and in negative of the recess of the imprint of the corresponding molds. 28. Machine for manufacturing packaging according to the preceding claim, characterized in that the central zone of the relief shape is retractable against springs. 29. Machine for manufacturing packaging according to one of claims 21 to 28, characterized in that the bottom of the imprints has orifices connected to first means for generating a vacuum. 30. A packaging manufacturing machine according to claim 29, characterized in that the inclined edges of the imprints have orifices connected to second means for generating a vacuum. 31. A packaging manufacturing machine according to one of claims 21 to 30, characterized in that the impressions of the thermoforming mold are formed in a tilting mold. 32. Packaging manufacturing machine according to one of claims 21 to 31, characterized in that it comprises a film drive stage consisting of pin chains located at the two lateral edges of the film, a roller made of elastomeric material being placed on each side at the inlet ends of the continuous film, or made up of chains with clips located at the two lateral edges of the film 33. Machine for manufacturing packaging according to one of claims 21 to 32, characterized in that it comprises an additional heating unit placed immediately upstream of the thermoforming stage. 34. Machine for manufacturing packaging according to one of claims 21 to 33, characterized in that each mold cavity has its own thermo-regulated heating means. 35. Machine for manufacturing packaging according to one of claims 21 to 34, characterized in that it comprises means for peripheral cutting of the containers. 36. Machine for manufacturing packaging according to the preceding claim, characterized in that said cutting means act on the periphery of the mold cavities.