Device and method for manufacturing an object by compression molding

Abstract

An apparatus for molding an object includes: an extrusion device (2) for supplying a continuous extrusion of polymer material; at least one separating element for cutting the continuous extrusion to separate a dose (6; 106) of polymer material from the continuous extrusion; at least one die (5; 105; 205; 305; 405) including a first die portion (9; 109; 209; 309) and a second die portion (8; 108; 508), the first die portion and the second die portion being movable relative to each other between an open position and a closed position, wherein in the open position the dose (6; 106) is rested on a receiving portion selected from the first die portion (9; 109; 209; 309) and the second die portion (8; 108; 508), and in the closed position a molding chamber is defined between the first die portion (9; 109; 209; 309) and the second die portion (8; 108; 508), the molding chamber having a shape corresponding to the object. The apparatus also includes a thermal conditioning device (11; 111; 211; 311; 411) configured to act on the dose (6; 106) by thermal conditioning of at least one surface portion (20; 120) of the dose (6; 106) that is different from the resting portion (17; 117) of the dose (6; 106) resting on the receiving portion, when the dose (6; 106) is positioned in the at least one mold (5; 105; 205; 305; 405) and before reaching the closed position.

Description

[0001] The present invention relates to apparatus and methods for manufacturing objects (e.g., containers, lids, preforms for containers, or other objects) by means of compression molding of polymer materials.

[0002] An apparatus for manufacturing an object by compression molding of a polymer material is known. The known apparatus includes an extruder for supplying a continuous extrusion of polymer material and a conveyor belt with a conveyor disc supporting multiple conveying elements. Each conveying element has a cutting edge adapted to interact with the continuous extrusion exiting the extruder. More specifically, as the conveying element passes near the extruder, the cutting edge separates a dose of molten polymer material from the continuous extrusion. This dose is then collected by the conveying element and conveyed until it reaches the vicinity of the die. At this point, the conveying element releases the dose into the die, allowing it to be shaped between a convex and concave portion of the die to form a desired object.

[0003] As the dose is delivered through the delivery element, the portion of the dose in contact with the delivery element cools more than the rest of the dose. This faster cooling of the dose due to contact with the delivery element creates a spot on the molded object, in which the molded object exhibits different aesthetic and optical properties compared to the surrounding area. This spot is clearly visible and undesirable because it detracts from the appearance of the molded object.

[0004] Defects that may occur on the molded object may also be located at the portions where the polymer material interacts with the cutting edge, by means of which the dose is separated from the continuous extrudate leaving the extruder. In addition to the portions affected by the cooling polymer material at the cutting edge, the cutting edge also produces dose edges where almost no polymer material is present. These edges cool rapidly until they are almost solidified and the polymer material exhibits a lack of uniformity as the dose is compressed between the convex and concave portions of the die. Therefore, regions lacking uniformity exist within the molded object.

[0005] During the cutting and / or delivery of the dosage, prematurely cooled portions of the polymer material may appear in areas of the molded object where the polymer material is weakly bonded to the surrounding polymer material due to its relatively low temperature (referred to as "cold-sealed areas"). These areas may constitute fracture trigger points during subsequent processes performed on the molded object, or during the life of the object itself. For example, if the molded object is a preform, fracture may occur during the transformation of the preform into a bottle by means of a blow molding process, or in the event of an accidental impact to the bottle or the bottle being dropped.

[0006] Examples of prior art apparatuses for manufacturing objects at least partially made of polymer materials are disclosed in US2003 / 0198708, US5401154 and US2016 / 0001510.

[0007] The object of the present invention is to improve the apparatus and method for manufacturing objects by means of compression molding of polymer materials.

[0008] Another objective is to provide an apparatus and method that allows for obtaining a compression-molded object with the most uniform properties possible.

[0009] Another objective is to provide an apparatus and method that allows for the manufacture of an object with good quality (even in terms of its appearance) by means of compression molding of a polymer material.

[0010] Another objective is to provide an apparatus and method for manufacturing an object by means of compression molding of a polymer material, wherein the molded object is substantially free from defects such as visible spots or cold-sealed areas caused by uneven cooling of the polymer material during operation prior to insertion into the mold.

[0011] In a first aspect of the invention, an apparatus for molding an object is provided, comprising: an extrusion device for supplying a continuous extrusion of polymer material; at least one separating element for cutting the continuous extrusion to separate a dose of polymer material from the continuous extrusion; at least one mold including a first mold portion and a second mold portion movable relative to each other between an open position and a closed position, wherein in the open position the dose is rested on a receiving portion selected from the first mold portion and the second mold portion, and in the closed position a molding chamber defined between the first mold portion and the second mold portion, the molding chamber having a shape corresponding to the object, wherein the apparatus further comprises a thermal conditioning device arranged to act on the dose by thermally conditioning at least one surface portion of the dose, different from the resting portion of the dose rested on the receiving portion, when the dose is disposed in the at least one mold and before reaching the closed position.

[0012] The heat conditioning device can act on the surface portion of the dose that is cooled during separation from the continuous extrudate and / or delivery toward the die. Therefore, the temperature of the surface portion of the dose can be restored to a value close to that of the polymer material in the remainder of the dose. This allows for a relatively uniform temperature distribution within the dose, which improves the quality of the molded article. In particular, it can prevent the presence of spots on the molded article due to premature cooling of the surface portion of the dose during cutting and / or delivery, or at least make these spots less visible than in the prior art.

[0013] It can also prevent or at least limit the presence of cold-sealed areas on the molded object that could subsequently form a fracture trigger point.

[0014] The heat transfer to the surface portion of the dose via a thermal conditioning device allows for localized softening of the dose until it melts or nearly melts. Consequently, any portion of the dose that has solidified during separation from the continuous extrudate and / or transport toward the die can be restored to viscosity conditions similar to adjacent portions. This allows the dose to flow uniformly within the molding cavity for molding the desired object. Therefore, objects molded by compression molding dose exhibit relatively uniform properties.

[0015] The thermal conditioning equipment is located outside the receiving section.

[0016] This allows for primary heating of the surface portion of the dose that is not resting on the receiving section, i.e., the surface portion of the dose exposed to air when it rests on the receiving section. This portion is typically the part that cools the most as the dose separates from the continuous extrudate and / or is conveyed toward the die, because it comes into contact with the mechanical parts of the device before the dose is released onto the receiving section.

[0017] In one embodiment, the apparatus includes a mobile device for moving a mold along a path, wherein a closed position is reachable by the mold downstream of an open position along the path.

[0018] The path of the mold can be a closed loop, such as a circle.

[0019] In an alternative implementation, the mold path can be linear, for example, straight.

[0020] In one embodiment, the heat conditioning device includes a containment structure arranged in a region between an open position and a closed position along the path of the mold to limit heat scattering toward the outside.

[0021] Due to the containment structure, heat is still confined to the vicinity of the mold when it is in the open position. This allows for the avoidance of cooling of the amount of heat that has already been released onto the receiving portion of the mold and will soon be formed between the first and second mold portions.

[0022] In one embodiment, the containment structure can only be heated by heat released through the mold portion and by the dose passing through the containment structure. No specific heating element is provided for heating the containment structure, thus limiting the use of passive thermal conditioning equipment.

[0023] In this case, the thermal regulation equipment is particularly simple and its energy consumption is very low.

[0024] In one embodiment, the thermal conditioning device includes a heating element for heating the air inside the containment structure.

[0025] The heating element can be a source for emitting hot air, a laser source, a plasma source, one or more infrared lamps, or others.

[0026] If the heat released through the mold section and through the dose passing through the interior of the containment structure is insufficient, then the thermal efficiency of the containment structure can be increased.

[0027] In one embodiment, the thermal conditioning device is a heating device configured to generate heat in order to heat the surface portion of the dose.

[0028] The heating device allows for effective heating of a predetermined surface portion of the dose.

[0029] The heating device can be configured to direct heat energy to a precise location on the surface portion of the dose.

[0030] This type of heating device is useful when you know very precisely where the dose cools the most during cutting and / or delivery, and thus can direct energy to that location.

[0031] In one embodiment, the heating device may include a laser source configured to emit a laser beam that can be shifted along a surface portion for heating that surface portion.

[0032] This allows the laser beam to move along a surface portion of any desired shape, taking into account the shape of the dose and the imprint formed on the dose by the components of the device in contact with the dose before the dose is positioned on the receiving portion of the mold.

[0033] In one embodiment, the first mold portion may include a convex mold portion. The second mold portion may include a concave mold portion.

[0034] In a second aspect of the invention, a method for forming an object is provided, comprising the following steps:

[0035] -Supply continuous extrusions of polymer materials

[0036] - Cutting the continuous extrudate to separate the dosage of polymer material from the continuous extrudate.

[0037] - Provide at least one mold including a first mold part and a second mold part;

[0038] -While the first mold portion and the second mold portion are separated by a distance from each other, the dose is positioned on the receiving portion selected from the first mold portion and the second mold portion;

[0039] - The first mold portion and the second mold portion are moved relative to each other until they reach a closed position, in which a molding chamber is defined between the first mold portion and the second mold portion, the molding chamber having a shape corresponding to the object.

[0040] Specifically, before reaching the closed position, at least one surface portion of a dose that is different from the resting portion of the dose resting on the receiving portion is thermally adjusted.

[0041] The method provided by the second aspect of the invention allows for the acquisition of the advantages previously described with reference to the apparatus of the first aspect of the invention.

[0042] In one embodiment, the surface portion of the thermally regulated dose is the portion that interacts with the separation element during the step of cutting the continuous extrudate to separate the dose from the continuous extrudate.

[0043] In one embodiment, the surface portion of the heat-regulated dose is the portion that interacts with the delivery element during the step of delivering the dose toward the die after the step of cutting the continuous extrusion.

[0044] In a third aspect of the invention, an apparatus for molding an object is provided, comprising: an extrusion device for supplying a continuous extrusion of polymer material; at least one separating element for cutting the continuous extrusion to separate a dose of polymer material from the continuous extrusion; at least one die including a first die portion and a second die portion movable relative to each other between an open position and a closed position, wherein in the open position the dose is rested on a receiving portion selected from the first die portion and the second die portion, and in the closed position a molding chamber defined between the first die portion and the second die portion, the molding chamber having a shape corresponding to the object, wherein the apparatus further comprises a local heat source for directing thermal energy to a selected portion of the dose before the dose deforms between the first die portion and the second die portion.

[0045] Due to the third aspect of the present invention, the temperature distribution inside the dose can be made more uniform.

[0046] In one embodiment, the apparatus includes at least one delivery element that can move along a trajectory for delivering a dose toward a mold.

[0047] The local heat source is located at a point on the trajectory.

[0048] This allows heat to be transferred to the dose as it is delivered toward the mold.

[0049] In one implementation, the local heat source is positioned such that heat is transferred to the dose when the dose falls on the receiving portion.

[0050] In a fourth aspect of the invention, a method for forming an object is provided, comprising the following steps:

[0051] -Supply continuous extrusions of polymer materials

[0052] - Cutting the continuous extrudate to separate the dosage of polymer material from the continuous extrudate.

[0053] - Provide at least one mold including a first mold part and a second mold part;

[0054] -When the first mold part and the second mold part are a certain distance apart from each other, the dose is positioned on the receiving part selected from the first mold part and the second mold part;

[0055] - The first mold portion and the second mold portion are moved relative to each other until they reach a closed position, in which the molding chamber is defined between the first mold portion and the second mold portion, and the molding chamber has a shape corresponding to the object.

[0056] Before reaching the closed position, the thermal energy emitted by the local heat source is directed to the surface portion of the dose.

[0057] The method according to the fourth aspect of the invention allows for the acquisition of the advantages previously described with reference to the third aspect of the invention.

[0058] The invention can be better understood and practiced by referring to the accompanying drawings, which illustrate several examples and non-limiting embodiments of the invention.

[0059] Figure 1 This is a schematic top view showing a portion of an apparatus for manufacturing objects by means of compression molding;

[0060] Figure 2 It shows the interior of the housing structure. Figure 1 A schematic cross-sectional view of the concave mold portion of the device;

[0061] Figure 3 It is shown in Figure 1 A schematic diagram of a convex mold portion on which a delivery element releases a dose of polymer material in an alternative embodiment of the device;

[0062] Figure 4 It shows a heating element similar to the one used for heating the dosage. Figure 3 A schematic diagram;

[0063] Figure 5 This illustrates a heating element similar to that of an alternative embodiment. Figure 4 A schematic diagram;

[0064] Figure 6This illustrates a heating element similar to that of another alternative embodiment. Figure 5 A schematic diagram;

[0065] Figure 7 It shows Figure 1 A schematic diagram of the concave mold portion of an alternative embodiment of the device, wherein a heating element is provided.

[0066] Figure 1 An apparatus 1 is shown for manufacturing an object by means of compression molding of a polymer material. The object obtained by the apparatus 1 can be a concave object, such as a container, a lid for a container, a preform for a container, a capsule for coffee or other powdered substances, or other types of objects.

[0067] The apparatus 1 includes an extrusion device 2 adapted to supply a continuous extrusion of polymer material. In the illustrated example, the polymer material exits the extrusion device 2 from top to bottom along a substantially vertical discharge direction, but other discharge directions are possible. For example, the polymer material can exit the extrusion device 2 from bottom to top along a substantially vertical discharge direction, or along a discharge direction inclined relative to the vertical direction.

[0068] The extrusion equipment 2 can be configured to supply continuous extrudates with a single-layer structure (i.e., made of a single polymer material), or alternatively to supply multilayer extrudates (i.e., comprising at least two layers of polymer materials that are different from each other).

[0069] The apparatus also includes at least one separating element, not shown in the figure, arranged to periodically pass near the outlet of the extrusion device 2 and to cut the continuous extrudate exiting the extrusion outlet. Thus, the separating element separates a dose 6 of polymer material, i.e., a predetermined mass of polymer material, from the continuous extrudate, from which an object can be obtained by compression molding. Figure 1 In the example shown, dose 6 can have a generally spherical, parallelepiped, or cylindrical shape. However, other shapes of dose 6 are possible.

[0070] The apparatus 1 also includes a conveying device 3, which includes at least one conveying element 4 for conveying the dose 6. In the illustrated example, multiple conveying elements 4 are provided. Figure 1 Only a portion of these conveying elements are shown schematically. Therefore, the conveying device 3 may include a conveyor belt with a conveyor disc.

[0071] The conveying element 4 can move along the trajectory T, which, in the example shown, is circular. However, this condition is not required, and the trajectory T can be a general trajectory with at least one non-circular stretching closed loop.

[0072] In the example shown, each conveying element 4 has a concave shape, such as a “C” or a “U”, wherein the concave portion faces the front of the forward direction F of the conveying element 4.

[0073] Each conveying element 4 has a cutting edge, which, in the illustrated example, is the upper edge of the conveying element 4. As the cutting edge passes near the outlet of the extrusion device 2, it separates the dose 6 from the continuous extrudate. Therefore, in this case, the cutting edge of the conveying element 4 acts as a separating element for separating the dose 6 from the continuous extrudate. The dose 6 is then received in a recess of the conveying element 4. The interior of the recess is defined by a conveying surface, to which the still-molten dose 6 can adhere due to its viscosity.

[0074] The apparatus 1 also includes at least one mold 5 for compressing the molding dose 6, which molds produce the desired object from the dose by means of compression molding. In the illustrated example, a plurality of molds 5 are provided mounted in the outer peripheral region of the mold disc conveyor 7, even if this condition is not required. Figure 1 Only a portion of the mold disc conveyor belt 7 is shown schematically.

[0075] Each mold 5 includes a first mold portion or convex mold portion 9 and a second mold portion or concave mold portion 8, which are aligned with each other along the molding direction, which is vertical in the illustrated example. The concave portion 8 has a cavity 10, while the convex portion 9 is provided with a punch.

[0076] The concave portion 8 and the convex portion 9 are movable relative to each other between an open position P1 and a closed position P2 due to an actuator device (not shown). In the open position P1, the concave portion 8 and the convex portion 9 are spaced apart, allowing a dose 6, for example, conveyed by a delivery element 4, to be inserted into the mold 5. In the closed position P2, the concave portion 8 and the convex portion 9 are close together, such that a molding chamber is defined between the concave and convex portions, the molding chamber having a shape corresponding to the object to be obtained.

[0077] exist Figure 1 In the example shown, the concave portion 8 is positioned below the convex portion 9. When the delivery element 4 is vertically aligned with the mold 5, the dose 6 is released through the delivery element. Therefore, the dose 6 falls into the lower cavity 10 of the concave portion 8.

[0078] Therefore, in this example, the concave portion 8 is the receiving portion, that is, the portion of the mold that receives the amount of material to be formed 6. However, this condition is not necessary, because, as will be described in more detail below, the receiving portion can be the convex portion 9.

[0079] When mold 5 is in the open position P1, the injection mold 6 is inserted into the mold. Then, the concave portion 8 and the convex portion 9 begin to move toward each other, and the injection mold 6 is shaped between the concave portion 8 and the convex portion 9 until the closed position P2 is reached, in which the injection mold 6 has been shaped into the desired form. Mold 5 remains in the closed position P2 for a predetermined period of time to allow the molded object to cool until it reaches a temperature at which it can be handled without damage. At this time, the concave portion 8 and the convex portion 9 move away from each other until they return to the open position P1. In the open position P1, the molded object can be removed from mold 5, and a new injection mold 6 can be inserted into mold 5 to repeat the molding cycle.

[0080] The apparatus 1 also includes a mobile device for moving the molds 5 along path P, which, in the illustrated example, is circular, even if this condition is not required. Each mold 5 reaches an open position P1 at a predetermined point on path P. Each mold 5 also reaches a closed position P2 at another predetermined point on path P, the other predetermined point being located downstream of the point reaching the open position P1 relative to the direction of movement M of the mold 5 along path P.

[0081] The apparatus 1 also includes a heat conditioning device 11, which is configured to be applied after the dose 6 is inserted into the mold 5 and more precisely when the dose 6 rests on the receiving portion of the mold 5 (i.e., during...). Figure 1 and Figure 2 In the example shown, the dose 6 is thermally regulated when it is placed on the concave portion 8.

[0082] The thermal conditioning device 11 is specifically configured to act on the dose 6, with the mold 5 into which the dose 6 is inserted located between the point on path P where it reaches the open position P1 and another point on path P where it reaches the closed position P2. In other words, the thermal conditioning device 11 is configured to thermally condition the dose 6 before the mold 5 reaches the closed position P2.

[0083] In the examples considered, such as in Figure 2 As shown in more detail, the heat conditioning device 11 includes a receiving structure 12 that at least partially surrounds the receiving portion of the mold 5 that delivers at least the dose 6 (i.e., at least the concave portion 8 in which the cavity 10 is formed).

[0084] The receiving structure 12 includes multiple walls defining a thermally modulating space 13, and the concave portion 8 moves the dose 6 within the thermally modulating space by moving along the path P. For example, in Figure 2In the illustrated embodiment, the receiving structure 12 includes a lower wall 14 positioned below the cavity 10, an upper wall 15 positioned above the concave portion 8, and two side walls 16 inserted between the lower wall 14 and the upper wall 15. Therefore, the receiving structure 12 can have a tubular shape surrounding at least a portion of the path P of the mold 5. In the illustrated example, where the path P is circular, the receiving structure 12 has an arcuate shape in the plan view.

[0085] The receiving structure 12 has an inlet opening through which the concave portion 8 of the mold can enter the receiving structure 12 near the point where the dose 6 is received in each concave portion 8. The receiving structure 12 also has an outlet opening through which the concave portion 8 can exit the receiving structure 12 near the point where the path P reaches the closed position P2.

[0086] like Figure 2 As shown, the receiving structure 12 has a channel 18 through which the rod 19 supporting the concave portion 8 of the mold 5 can pass.

[0087] The receiving structure 12 has the function of maintaining a relatively high temperature along the extension of path P, in which the dose 6 is released into the mold 5 and is not yet fully formed. This occurs because the receiving structure 12 prevents or, in any case, limits heat scattering to its own exterior. The air present in the receiving structure 12 is kept relatively hot by the heat transferred from the dose 6 resting on the corresponding concave portion 8, which passes through the interior of the receiving structure 12.

[0088] In one embodiment, the concave portions 8 of the mold 5 are thermally conditioned to have a relatively high temperature. In this case, the air present in the receiving structure 12 is also continuously heated by the concave portions 8 of the mold 5, which extend along path P through the interior of the receiving structure 12.

[0089] In an alternative embodiment, the concave portions 8 of the mold 5 can be thermally adjusted to have a relatively low temperature. In this case, the contribution of the concave portions 8 of the mold 5 to heating the air present in the receiving structure 12 is negligible.

[0090] In an alternative embodiment not shown, the receiving structure 12 may include a structure larger than that shown in the figure. Figure 2 The example shown has fewer walls. The housing structure 12 could, for example, not have an upper wall 15; in this case, the housing structure 12 would have a very simple construction, but would still limit heat scattering outwards. Figure 1 and Figure 2In the example shown, the thermal conditioning device 11 is of the passive type, meaning it uses heat released through the dose 6 and through some components of the device 1 (if present) (such as the concave portion 8) to maintain a relatively high temperature within the containment structure 12. A heating element for actively heating the air inside the containment structure 12 may also be provided. The active heating element may include, for example, a hot air source, a laser source, a plasma-type heating element, or others. The active heating element may include one or more infrared lamps positioned inside the containment structure 12. One or more reflectors may be disposed on the wall of the containment structure 12 to guide the infrared light toward the dose 6.

[0091] During operation, the extrusion unit 2 supplies a continuous extrusion of polymer material. Each conveying element 4 passes near the outlet of the extrusion unit 2 and cuts the continuous extrusion, separating the dose 6 from the continuous extrusion. The conveying element 4 moves the dose 6 along the trajectory T until it reaches the position between the concave portion 8 and the convex portion 9 of the die 5. At this point, the dose 6 is released through the conveying element 4 and falls into the cavity 10 of the lower concave portion 8. Thus, the dose 6 rests on the concave portion 8 at the dose 6 resting portion 17. The die 5 is in the open position P1.

[0092] The dose 6, deposited in the cavity 10, moves along path P through the receiving structure 12. The air present in the receiving structure 12 keeps the dose 6 relatively hot, thus preventing the dose 6 from cooling or increasing its surface temperature. In particular, the air present in the receiving structure 12 acts on the surface portion 20 of the dose 6 that is different from the resting portion 17 of the dose 6 resting on the concave portion 8, that is, on the surface portion 20 of the dose 6 exposed to air.

[0093] Any portion of the surface of the heated dose 6 that cools before the dose 6 is deposited in the mold 5, such cooling is due, for example, to the interaction between the dose 6 and the cutting edge of the conveying element 4 from which the dose 6 is separated from the extruder 2, or to the interaction between the dose 6 and the conveying surface of the conveying element 4 as the dose 6 is brought toward the mold 5.

[0094] Therefore, when the mold 5 is brought into the closed position P2 and the dose 6 is compressed between the concave portion 8 and the convex portion 9, the dose 6 has a relatively uniform temperature. This allows the polymer material constituting the dose 6 to flow easily between the concave portion 8 and the convex portion 9, thereby producing a molded object of good quality.

[0095] In particular, this avoids cracking trigger points or spots on the surface of the molded object caused by premature cooling due to contact between a portion of dose 6 and the cutting edge and / or the delivery surface of delivery element 4. In effect, the portion of dose 6 that has prematurely cooled during cutting and / or delivery is reheated as dose 6 passes through receiving structure 12, allowing for a relatively uniform temperature distribution on the surface of dose 6 and between the surface of dose 6 and the core of dose 6, which is naturally hotter than its surface.

[0096] Figure 3 and Figure 4 A mold 105 for manufacturing an object by means of compression molding, according to an alternative embodiment, is schematically shown.

[0097] Figure 3 and Figure 4 The mold 105 shown is different from Figure 1 and Figure 2 The mold 5 shown is distinguished primarily by including a convex portion 109 positioned below the concave portion 108. The convex portion 109 is aligned with the concave portion 108 along the molding direction, which is vertical in the illustrated example. Therefore, in this embodiment, the convex portion 109 serves as a receiving portion on which the dose 106 is deposited.

[0098] More specifically, the convex portion 109 is defined in its upper region by the receiving surface 21, on which the dose 106 is intended to rest. More specifically, the dose 106 is intended to rest on the convex portion 109 at a resting portion 117. In the illustrated example, the receiving surface 21 is substantially flat, but other geometries are possible for the receiving surface 21.

[0099] For reference Figure 1 and Figure 2 The apparatus described in shown device 1, including a die 105, comprises an extruder arranged for supplying a continuous structure that can be made from a single material or multiple layers. The extruder has a rectangular outlet such that the continuous structure has a sheet-like shape, from which doses 106, substantially parallelepiped or cubic, can be separated. (As shown in...) Figure 3 and Figure 4 As can be seen, the dose 106 is defined by a pair of larger faces, each of which may be rectangular or square. One of the two larger faces is intended to rest on the receiving surface 21, while the other larger face, opposite to the face intended to rest on the receiving surface 21, is arranged to contact the conveying element 104 which has the function of conveying the dose 106 from the extruder toward the die 105.

[0100] The distance between the larger surfaces of dose 106 defines the thickness of dose 106. In the example shown, the thickness of dose 106 is less than the linear dimension of the two larger surfaces.

[0101] Figure 3 and Figure 4 The conveying element 104 of the device shown has a different Figure 1 and Figure 2 The structure of the delivery element 4 of the device 1 shown. Each delivery element 104 is defined by a flat delivery surface 22, to which the larger surface of the dose 106, which is intended to contact the receiving surface 21, is adhered.

[0102] In addition to being able to move along trajectory T, as previously referenced Figure 1 As described, each conveying element 104 is rotatable about the axis R of the arm 23, and the conveying element 104 is connected to the arm. Thus, in addition to conveying the dose 106 from the extruder toward the die 105, the conveying element 104 can also rotate the dose 106 from an initial configuration to a final configuration in which the dose 106 is present at the extruder exit and can be substantially vertical or tilted relative to the vertical direction, and the final configuration is substantially horizontal, in which the dose 106 is released onto the convex portion 109 of the die 105.

[0103] The conveying element 104 has a cutting edge 24, which, when the conveying element 104 passes near the outlet, can cut the continuous extrudate leaving the extruder for separating the dose 106 therefrom. Thus, the cutting edge 24 functions as a separating element for separating the dose 106 from the polymer material leaving the extruder.

[0104] When the mold 105 is in the open position, the delivery element 104 is arranged to deposit the dose 106 onto the receiving portion of the mold 105, i.e., onto the convex portion 109. For simplicity, in Figure 3 The concave portion 108 is not shown in the diagram.

[0105] After dose 106 is released onto the convex portion 109, the delivery element 104 moves away from the mold 105 by moving along the trajectory T. The convex portion 109 and the concave portion 108 move relative to each other until they are in a closed position, in which the desired object is formed between the convex portion 109 and the concave portion 108.

[0106] The convex portion 109 and the concave portion 108 are supported by a support structure 25, which in the illustrated example is the body of the molded disc conveyor belt 7.

[0107] The apparatus also includes a thermal conditioning device 111 for thermally conditioning the dose 106 after it is placed on the receiving portion (i.e., on the convex portion 109) and before the mold 105 reaches the closed position.

[0108] The thermal conditioning device 111 includes a heating element, which in the illustrated example includes a laser source 26 adapted to emit a laser beam 27 having an appropriate wavelength.

[0109] In addition, a system for reflecting mirror 28 is provided for redirecting laser beam 27 to direct the laser beam onto dose 106. In the illustrated example, the system for reflecting mirror 28 is depicted as being positioned outside laser source 26, but this condition is not required. The system for reflecting mirror 28 can also be included within laser source 26.

[0110] The laser beam 27 is arranged to be guided onto the surface portion 120 of the dose 106, which is different from the resting portion 117 of the dose 106 resting on the convex portion 109 of the mold 105.

[0111] In the illustrated example, the surface portion 120 is located near the edge of the dose 106, on which the cutting edge 24 of the delivery element 104 acts to separate the dose 106 from the continuous extrudate. Due to contact with the cutting edge 24, the polymer material forming the dose 106 is cooled. In some cases, the polymer material constituting the dose 106 is very thin near the edge on which the cutting edge 24 acts, and may even harden to a localized solidification point.

[0112] The laser beam 27 allows heating of the polymer material comprising dose 106 near or at the edge on which the cutting edge 24 is applied. This softens the previously hardened polymer material to prevent crystallization or premature curing in the mold 105, which could introduce defects into the molded object.

[0113] As an alternative or supplement to the above, the surface portion 120 that the laser beam 27 allows to be heated can be located on the surface of the dose 106 opposite to the surface of the receiving surface 21 of the contact convex portion 109, that is, on the surface of the dose 106 that contacts the delivery surface 22 of the delivery element 104 during delivery. In fact, the surface of the dose 106 can also be cooled due to contact with the delivery element 104.

[0114] exist Figure 3 and Figure 4 In the device shown, the surface portion of the dose 106 that interacts with the delivery element 104 and / or the cutting edge 24 can be accurately identified.

[0115] Therefore, the laser beam 27 can be precisely guided to the surface portion of the dose 106 that is actually cooled during the cutting and / or transfer of the dose 106, so as to effectively heat those portions. That is, the laser beam 27 can locally and specifically transfer heat to the surface portion of the dose that was previously cooled the most and thus would flow non-uniformly or produce surface defects on the molded object during the filling of the mold 105.

[0116] In the illustrated example, after the dose 106 rests on the receiving portion of the mold 105, the dose 106 moves along path P. It is also possible that, in order to bring the mold 105 from the open position to the closed position, the receiving portion on which the dose 106 rests (i.e., the convex portion 109 in the illustrated example) moves toward another portion of the mold 105 (i.e., the concave portion 108 in the illustrated example).

[0117] In the illustrated example, the laser source 26 is mounted on the support structure 25 of the supporting mold 105. The support structure 25 is configured to move along path P together with the laser source 26.

[0118] The system of reflector 28 is configured to shift the laser beam 27 such that as the dose 106 is carried from the convex portion 109 to the concave portion 108, the laser beam 27 follows the movement of the dose 106. The system of reflector 28 is also configured to shift the laser beam 27 along the surface portion 120 of the dose 106, such that the laser beam 27 heats the surface portion 120 of the dose 106 not in a point-like manner but with a predetermined surface range. Therefore, the laser beam 27 is able to "brush" the surface portion 120 of the dose 106 that contacts the cutting edge 24 and / or the delivery surface 22.

[0119] During operation, after the dose 106 is released onto the convex portion 109 of the die 105 in the open position, the laser source 26 is activated, causing it to emit a laser beam 27. Before the die 105 reaches the closed position, the laser beam interacts with the dose 106 resting on the receiving portion of the die 105. Specifically, the laser beam 27 is directed to the edge of the dose 106 that has separated from the continuous extrudate, and / or to the surface of the dose 106 opposite the resting surface 117, in order to heat the surface portion 120 of the dose 106 that cools most during cutting and / or during delivery.

[0120] The shape of the mold 105 makes it particularly easy to heat the surface portion of the dose 106 using the laser beam 27. In fact, because the dose 106 rests on the convex portion 109, there is no portion of the receiving portion that would block the laser beam 27. Conversely, if the dose 106 were received in the cavity of the concave mold portion, then a portion of the receiving portion that would block the laser beam would appear. Figure 5 A mold 205 according to an alternative embodiment is shown in part, which differs from... Figure 3 and Figure 4 The embodiment shown is associated with a heat conditioning device 211, which includes a laser source 226 arranged in a fixed position relative to a convex portion 209 of a mold 205.

[0121] Specifically, a support element 29 is provided, which is fixed relative to the convex portion 209 and supports the laser source 226, and, if necessary, also supports a system for directing the laser beam 227 emitted by the laser source 226 toward the dose 106.

[0122] If the convex portion 209 can move along a molding direction for moving away from or toward the corresponding concave portion, then the laser source 226 moves together with the convex portion 209. Therefore, the laser beam 227 only needs to move to reach the desired point on the surface portion 120 to which the heat is transferred 106. In other words, in Figure 5 In this embodiment, the laser beam 227 only performs movement of a point on the surface portion 120 of the dose 106 to be heated. Conversely, when the convex portion 209 moves toward the corresponding concave portion, it is not necessary to provide movement following the convex portion.

[0123] Figure 6 A mold 305 according to an alternative embodiment is shown in part, which differs from... Figure 3 and Figure 4 The mold shown is associated with a heat treatment device 311, which includes a laser source 326 arranged in a fixed position on the device to which the mold 305 belongs.

[0124] The laser source 326 is configured to shift the laser beam 327 according to three types of movement, namely:

[0125] - Follow the movement of dose 106 as it travels along path P of mold 305;

[0126] - The dose 106 moves further as it moves through the convex portion 309 toward the concave mold portion;

[0127] - Scanning movement of the molding direction moving point for transferring heat to all surface portions 120 of the dose 106 to be heated.

[0128] exist Figure 5 and Figure 6 The heat regulation devices 211 and 311 shown in the reference are similar to those in the previous reference. Figure 3 and Figure 4It operates in the same manner as described, and in particular, allows heat transfer to the edge of the dose 106, where the dose 106 interacts with the separation element for separation from the continuous extrudate, or allows heat transfer to the surface of the dose 106 in contact with the delivery element.

[0129] Figure 3 , Figure 4 as well as Figure 5 The solution shown uses a laser source for each mold, while Figure 6 The solution shown uses a single laser source for all molds or for a set of molds. Therefore, compared to... Figures 3 to 5 Compared to the solution shown, Figure 6 The solution shown requires fewer components and fewer laser sources. However, in Figures 3 to 5 The solution shown makes it easier to control the movement of the laser beam.

[0130] Figure 7 A mold 405 according to an alternative embodiment is partially shown. Mold 405 is similar to... Figure 1 and Figure 2 The mold 5 shown includes a concave portion 508 positioned below the convex portion, the concave portion 508 having an upward-facing cavity 10.

[0131] Dose 6, for example, through Figure 1 The delivery element of the type shown is deposited in the cavity 10. The dose 6 is placed on the concave portion 508 at the dose resting portion 17.

[0132] In addition, a heat conditioning device 411 is provided, which includes a hot air source 30 arranged for heat conditioning of the surface portion 20 of the dose 6. The surface portion 20 is different from the resting portion 17 arranged to contact the concave portion 508. When the mold 405 is in the open position, the surface portion 20 is exposed to air.

[0133] Hot air source 30 is positioned along path P of mold 405 in the area where dose 6 is deposited in cavity 10 but mold 405 has not yet reached the closed position.

[0134] The hot air source 30 emits hot air that allows heating of the surface portion 20 of the dose 6, particularly at the points where the dose 6 interacts with the separation and / or delivery elements. This allows for a more uniform temperature distribution throughout the dose and especially on the surface of the dose, thus improving the quality of the formed object.

[0135] A flame processing unit, one or more infrared lamps, plasma equipment, or other heat sources can be provided to replace the hot air source 30.

[0136] The above is for reference only. Figures 1 to 7The features of the described implementation methods can also be combined differently from those explicitly mentioned. For example, refer to Figure 1 and Figure 2 The described containment structure 12 or reference Figure 7 The described hot air source 30 can also be used in a device in which the convex mold portion is positioned below the concave mold portion. Similarly, Figures 4 to 6 The laser source shown can also be used in conjunction with a mold in which the concave part is positioned below the convex part.

[0137] Thermal conditioning equipment can be of the static type, such as in Figure 1 and Figure 7 In the example described, the heat treatment device is arranged in a fixed position and heats a predetermined area of ​​the mold's path. Alternatively, the heat treatment device can be of a dynamic type, as in... Figures 4 to 6 In one example, the thermal conditioning device allows for the sequential heating of different points of the dose.

[0138] Reference is made to a device comprising multiple molds mounted in the outer peripheral region of a mold disc conveyor belt, the mold disc conveyor belt being rotatable about its axis.

[0139] However, the above description of heating of the dosage in the reference heat conditioning equipment and mold can also be applied to devices that include only one mold instead of multiple molds.

[0140] Furthermore, one or more molds can move along a path that is not necessarily circular (e.g., a linear path or a general path that is closed in a loop).

[0141] The conveying equipment, including the conveying element that carries the dose from the extruder to the die, is not essential, but may be unnecessary if an arrangement of extruder and die different from that described above is used.

[0142] The dose can be separated from the continuous extrudate not only by means of a separating element mounted on the conveying element, but also by means of a separating element different from any conveying element (such as a blade or laser beam between the extruder and the conveying device).

[0143] If the object to be obtained does not have a concave shape, the concave mold portion and the convex mold portion can be replaced by a common first mold portion and a common second mold portion (i.e., replaced by a mold portion that does not have a punch and / or cavity).

[0144] Throughout the above description, reference is always made to the heat treatment equipment positioned along the path of the mold.

[0145] More specifically, the heat treatment device can be positioned along the path of the mold. This position could be between a point in the path where the receiving portion of the mold receives the dose and another point in the path where the mold reaches the closed position. For example... Figure 7 The thermal conditioning equipment shown is in good condition.

[0146] As a special case for the above reference, the location of the heat treatment device can extend from the point where the receiving part of the mold receives the dose in the path to another point in the path where the mold reaches the closed position, such as... Figure 1 and Figure 2 As shown.

[0147] It is also possible that the heat conditioning device is activated when the mold is in a portion of the path between the point where the receiving portion of the mold receives the dose and another point where the mold reaches the closed position, regardless of the location of the heat conditioning device. This can occur, for example, when the heat conditioning device can move along the path of the mold with the mold or a portion thereof (e.g., Figure 3 , Figure 4 as well as Figure 5 (as shown), or the thermal conditioning equipment is positioned in a stationary position (e.g. Figure 6 (This can happen in the implementation of the method).

[0148] The activation of the thermal conditioning device can occur, for example, by generating a laser beam or by activating heat generated by any other heat source included in the thermal conditioning device.

[0149] These are examples of thermal conditioning devices configured to apply the dose while it is positioned in the mold and before it reaches the closed position.

[0150] As a supplement or alternative to the above description, a heat conditioning device located upstream of the mold can be provided, which acts on the dose before the dose is placed on the receiving part of the mold.

[0151] In this case, the thermal conditioning device may include a localized heat source suitable for directing thermal energy to a selected surface portion of the dose.

[0152] Local heat sources can be laser sources, infrared lamps, flame processing units, or plasma devices, etc.

[0153] For example, such as Figure 1 As shown, a local heat source can be provided, including a laser source 511 positioned at a predetermined point along the trajectory T of the conveying element 4.

[0154] The laser source 511 is positioned such that the laser beam is directed onto the surface portion of the dose 6 exposed to air (i.e., without adhering to the corresponding delivery element 4). The laser beam can be moved with the scan to heat a predetermined area of ​​the surface portion of the dose.

[0155] This allows for heating of the dosage, which is more uniform and allows for the acquisition of objects of good quality.

[0156] Local heat sources can also be different from Figure 1 The conveying element shown (e.g., Figure 3 Used in conjunction with conveyor elements of the type shown, or with different types of conveyor elements. Figure 1 The concave mold portion and the convex mold portion shown are arranged in combination (e.g., the convex mold portion is positioned below the concave mold portion).

[0157] Local heat sources can also be positioned at different points along the dose's path, such as in the area where the dose is released onto the receiving portion of the mold. For example, a local heat source can be configured to direct heat energy onto the dose as it descends toward the receiving portion of the mold.

[0158] More typically, the heat conditioning device can therefore be positioned at any point along the path the dose follows, from the moment the dose is cut from the continuous extruder until the moment the die into which the dose is inserted reaches the closed position.

[0159] In summary, the method for forming objects includes the following steps:

[0160] - Supply of continuous extrusions of polymer materials;

[0161] - Cut the continuous extrudate and separate the dosage of polymeric material (6; 106) from the continuous extrudate.

[0162] - Provide at least one mold (5; 105; 205; 305; 405) including a first mold portion (9; 109; 209; 309) and a second mold portion (8; 108; 508);

[0163] -While the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508) are positioned at a distance from each other, a dose (6; 106) is positioned on a receiving portion selected from the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508);

[0164] - The first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508) are moved relative to each other until they reach a closed position, in which a molding chamber is defined between the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508), the molding chamber having a shape corresponding to the object.

[0165] Before reaching the closed position, the thermal energy emitted by the local heat source (511) is directed to the surface portion (6; 106) of the dose.

[0166] In one embodiment, the surface portion (20; 120) of the thermally regulated dose (6; 106) interacts with the separation element during the step of cutting the continuous extrudate for separating the dose (6; 106) from the continuous extrudate.

[0167] An apparatus for molding an object includes: an extrusion device (2) for supplying a continuous extrudate of polymer material; at least one separating element for cutting the continuous extrudate to separate a dose (6; 106) of polymer material from the continuous extrudate; at least one die (5; 105; 205; 305; 405) including a first die portion (9; 109; 209; 309) and a second die portion (8; 108; 508), the first die portion and the second die portion being movable relative to each other between an open position and a closed position, wherein in the open position, the dose (6; 106) is placed in a container selected from the first die portion. In the closed position, the molded cavity is defined between the first molded portion (9; 109; 209; 309) and the second molded portion (8; 108; 508) on the receiving portion of the molded portion (9; 109; 209; 309) and the second molded portion (8; 108; 508), and the molded cavity has a shape corresponding to the object. The device also includes a local heat source (511) for directing heat energy to a selected portion of the dose (6: 106) before the dose (6) deforms between the first molded portion (9; 109; 209; 309) and the second molded portion (8; 108; 508).

[0168] In one embodiment, the apparatus further includes at least one delivery element (4; 104) movable along a trajectory (T) for delivering a dose (6; 106) toward at least one mold (5; 105; 205; 305; 405), with a local heat source (511) positioned at a point on the trajectory (T) to direct heat to the portion of the dose (6; 106) that is not in contact with the delivery element (4; 104) when the dose (6; 106) is associated with the delivery element (4; 104).

[0169] In one embodiment, a local heat source (511) is positioned such that heat is transferred to the dose (6; 106) as the dose (6; 106) drops onto the receiving portion.

[0170] In one embodiment, the local heat source (511) is selected from the group consisting of: laser source, flame processing unit, infrared lamp, plasma device.

Claims

1. An apparatus for forming an object, comprising: Extrusion equipment (2) for supplying continuous extrusions of polymer materials; At least one separating element for cutting the continuous extrudate to separate a dose (6; 106) of polymer material from the continuous extrudate; the apparatus includes at least one die (5; 105; 205; 305; 405) moving along a path (P); and at least one conveying element (4; 104) moving along a trajectory (T) for conveying the dose (6; 106) from the extrusion device (2) to the die (5; 105; 205; 305; 405); the trajectory (T) is a closed loop and intersects the path (P) at a common release section, in which the conveying element (4; 104) releases the dose onto a receiving portion of the die (5; 105; 205; 305; 405); the die (5; 105; 205; 305; 405) includes first die portions (9) aligned with each other in the molding direction. 109; 209; 309) and the second mold part (8; 108; 508), the first mold portion and the second mold portion are movable relative to each other between an open position and a closed position, in which the dose (6; 106) rests on the receiving portion selected from the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508), and in the closed position, a molding chamber is defined between the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508), the molding chamber having a shape corresponding to the object, wherein the device further includes a heat conditioning device (11; 111; 211; 311; 411) different from the delivery element (4; 104), wherein the heat conditioning The device (11; 111; 211; 311; 411) functions at least partially downstream of the release section along the path (P) to act on the dose (6; 106) after it has been released into the at least one mold (5; 105; 205; 305; 405) and before reaching the closed position, when the dose is between the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508), by thermally conditioning at least one surface portion (20; 120) of the dose (6; 106), which is different from the resting portion (17; 117) of the dose (6; 106) resting on the receiving portion.

2. The apparatus according to claim 1, wherein, The heat conditioning device (11; 411) is positioned along the path (P) of the at least one mold (5; 405) in a location between the common release section and another point where the at least one mold (5; 405) of the path (P) reaches the closed position.

3. The apparatus according to claim 2, wherein, The heat conditioning device (11) extends from the common release section along the path to the other point of the at least one mold (5) of the path (P) to the closed position.

4. The apparatus according to claim 1, wherein, The heat regulation device (111; 211; 311) is adapted to be activated in a position between the common release section and another point on the path (P) of the at least one mold (105; 205; 305) where the at least one mold (105; 205; 305) reaches the closed position.

5. The apparatus according to claim 1, wherein, The thermal conditioning device (11; 111; 211; 311; 411) is located outside the receiving part.

6. The apparatus according to claim 1, wherein, The thermal conditioning device (11; 111; 211; 311; 411) includes a laser source (26; 226; 326) for emitting a laser beam (27; 227; 327) which is intended to be directed onto the surface portion (20; 120) of the dose (6; 106).

7. The apparatus according to claim 6, wherein, The laser source (26; 226; 326) is configured to move the laser beam (27; 227; 327) such that the laser beam (27; 227; 327) scans multiple points of the surface portion (20; 120) of the dose (6; 106).

8. The apparatus according to claim 6, wherein, The laser source (26; 226; 326) is positioned in a fixed position, and the at least one mold (5; 105; 205; 305; 405) is movable relative to the laser source (26; 226; 326).

9. The apparatus according to claim 1, wherein, The thermal conditioning device (11; 111; 211; 311; 411) includes a heat source (30) positioned along the path (P), the heat source (30) being located between a point on the path (P) that is accessible to the open position and another point on the path (P) that is accessible to the closed position.

10. The apparatus according to claim 9, wherein, The heat source (30) is selected from the group consisting of: hot air source, flame processing unit, infrared lamp, plasma device.

11. The apparatus of claim 1, further comprising a mobile device for displacing the mold (5; 105; 205; 305; 405) along the path (P), the heat conditioning device (11; 111; 211; 311; 411) comprising a receiving structure (12) positioned in a region of the path (P) between a point on the path (P) accessible to the open position and another point on the path (P) accessible to the closed position, for limiting heat scattering toward the outside.

12. The apparatus of claim 11, further comprising a heating element for heating the air inside the housing structure (12).

13. The apparatus according to claim 12, wherein, The heating element includes at least one infrared lamp positioned inside the housing structure (12) and at least one reflector associated with the wall of the housing structure (12), the at least one reflector being used to guide infrared light toward the surface portion (20; 120) of the dose (6; 106).

14. A method for forming an object, the method comprising the following steps: - Provide extrusion equipment (2) to supply continuous extrusions of polymer materials, - Cutting the continuous extrudate to separate a dose of polymer material (6; 106) from the continuous extrudate, providing at least one die (5; 105; 205; 305; 405) moving along a path, the at least one die (5; 105; 205; 305; 405) comprising a first die portion (9; 109; 209; 309) and a second die portion (8; 108; 508) aligned with each other along the molding direction; - The dose (6; 106) is conveyed from the extrusion device (2) to the die (5; 105; 205; 305; 405) using at least one conveying element (4; 104) that moves along a closed loop trajectory (T). - While the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508) are at a distance from each other, the dose (6; 106) is positioned on the receiving portion selected from the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508), the positioning location being the common release segment between the trajectory (T) and the path; - The first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508) are moved relative to each other until a closed position is reached, in which a molding chamber is defined between the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508), the molding chamber having a shape corresponding to the object. Specifically, prior to reaching the closed position and downstream of the operation of the release section, at least one surface portion (20; 120) of the dose (6; 106) is thermally conditioned by a thermal conditioning device (11; 111; 211; 311; 411) different from that of the delivery element (4; 104), at which time the dose (6; 106) is between the first mold portion (9; 109; 209; 309) and the second mold portion (8; 108; 508) and rests on the receiving portion, wherein the at least one surface portion (20; 120) is different from the resting portion (17; 117) of the dose (6; 106) resting on the receiving portion.

15. The method according to claim 14, wherein, The surface portion (20; 120) of the heat-regulated dose (6; 106) interacts with the separation element during the step of cutting the continuous extrudate for separating the dose (6; 106) from the continuous extrudate.

16. The method of claim 14, wherein, The surface portion (20; 120) of the heat-regulated dose (6; 106) interacts with the delivery element (4; 104) that delivers the dose (6; 106) toward the die (5; 105; 205; 305; 405) after the step of cutting the continuous extrusion.

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