Continuous cycle system and method for molding a single object from a plastic material

Abstract

1. A continuous cycle system (1) for molding a single object from a plastic material, the continuous cycle system (1) including: an extruder (2) including a cylinder (21) extending along a longitudinal axis (L); a screw (22) rotating inside the cylinder (21) about the longitudinal axis (L), the screw (22) having a core (221) and threads (222) coupled to the exterior of the core (221); and a heater (26) coupled to the cylinder (21); and a molding machine (3) configured to receive a flow of liquid plastic material from the extruder (2) as an input, the molding machine (3) including a plurality of molds (31), each having first and second mold halves (310, 311) movable relative to one another between an open position and a closed position.

Description

[Technical Field]

[0001] The present disclosure relates to a continuous cycle system for molding a single object from a plastic material. The present disclosure also relates to an extruder for a polymeric material and a method for extruding a polymeric material.

[0002] FIELD OF THE DISCLOSURE The present disclosure deals with the field of continuous cycle systems for molding single objects from plastic materials, such as parisons that are blow molded to form bottle caps or bottles.

[0003] Systems used for this purpose include an extruder designed to receive the plastic material in raw form and to deliver a stream of the plastic material in liquid phase, and a molding machine configured to receive as input the stream of liquid plastic material from the extruder. More particularly, the present disclosure relates to systems in which the molding machine operates by compression or injection compression, although alternatively, molding machines operating by injection are also known in the prior art. [Background technology]

[0004] An example of a system for producing plastic objects in a continuous cycle from a plastic material using a compression moulding machine is described in patent document WO 2018 / 025150 A1 in the name of the Applicant and for producing plastic objects in a continuous cycle from a plastic material, while another example of a system using an injection compression moulding machine is described in patent document WO 2011161649 A1.

[0005] Other solutions relating to continuous cycle systems for molding single objects from plastic materials are provided by patent documents WO 2019207420 A1 and EP 2585273 A1, which illustrate examples of injection molding systems.

[0006] With regard to the extruder, it should be recognized that the possible applications of the extruder are not limited solely to the continuous cycle production of single objects from plastic material using a molding machine, but also include extrusion plants for making long parts (profiles or draw moldings) and extrusion blow molding plants in which the extruder is directly coupled to a blow molding machine, examples of which are described in patent document WO 2018025100 in the name of the applicant. In this context, patent documents DE 10130759 A1 and EP 1 194278 B1 describe extruders specially designed for such applications, extrusion plants for producing long parts and extrusion blow molding plants, which extruders have a barrier screw coupled to a grooved cylinder.

[0007] Another example of this type of extruder is described, for example, in patent document CN103496147A.

[0008] On the other hand, prior art extruders for compression molding and injection compression molding applications have different characteristics, typically the inner surface of the cylinder is smooth, i.e. not grooved, especially in the zone where the plastic melts.

[0009] Generally speaking, there is a need to increase the production speed of these systems. Another typical need for these systems is to improve the quality of the molded plastic objects. To achieve these goals, the efforts of manufacturers of these systems have primarily focused on molding machines to make them more efficient and sophisticated. However, there remains a need to further improve the production capacity of the systems and the quality of the molded objects.

[0010] Additionally, there is a need to improve the reliability of extruders and increase their working life. Summary of the Invention [Problem to be solved by the invention]

[0011] SUMMARY OF THE INVENTION The present invention aims to provide a continuous cycle system and method for molding a single object from a plastic material to overcome the above-mentioned shortcomings of the prior art.

[0012] This object is fully achieved by the systems and methods of the present disclosure as characterized in the appended claims.

[0013] More particularly, it is an object of the present disclosure to provide a continuous cycle system and method for molding a single object from a plastic material to enable certain high production rates to be achieved.

[0014] Another object of the present disclosure is to provide a continuous cycle system and method for molding a single object from a plastic material, particularly to enable the creation of objects with a high level of precision and quality. [Means for solving the problem]

[0015] Accordingly, the present disclosure relates to a system, preferably a continuous cycle system, for molding a single object from a plastic material.

[0016] The object may be, for example, a bottle cap, a capsule for the production of infused drinks, a disposable container for a sanitary device or another object.

[0017] The system includes an extruder designed to receive the plastic material in a raw form and to deliver a stream of the plastic material in a liquid phase.

[0018] The extruder includes a cylinder extending along a longitudinal axis between an inlet and an outlet, a screw rotating about the longitudinal axis inside the cylinder, and a core and threads coupled to the exterior of the core.

[0019] The extruder also includes a heater coupled to the cylinder. In one embodiment, the heater includes a resistance system. In another embodiment, the heater includes an electromagnetic inductor.

[0020] The system includes a molding machine designed to receive a stream of liquid plastic material from an extruder. The machine includes a plurality of molds, each having first and second mold halves, movable relative to one another between a mold open position to allow removal of an object from the mold and a mold closed position in which the first and second mold halves define an enclosed molding space. In one or more embodiments, the molding machine includes a metering unit configured to separate from the stream of plastic material a predetermined amount of plastic material forming each charge inserted into a corresponding mold of the plurality of molds. More particularly, a metering unit is provided in embodiments in which the molding machine is a compression molding machine, but is not provided in embodiments in which the molding machine is an injection molding machine.

[0021] According to one embodiment, the metering unit includes a separation element that is distinguished by a simple interruption of the flow of the plastic material, as occurs, for example, in injection molding. In the case of compression molding or injection-compression molding referred to in the present invention, the extruder is configured to extrude a paste (non-liquid) material, which is then separated from the plastic material rod to define a paste dose, which is then compressed. In some embodiments, the separation element is a knife that rotates around a fulcrum that periodically encounters the plastic material rod to separate a portion of the material from the material rod to define the dose. In this case, the rotation period of the knife and the extrusion speed are synchronized to define the correct amount of dose to be provided.

[0022] Furthermore, in some embodiments, the metering unit comprises a transfer element for transferring the dose from the extruder to a mold, in which the dose is compressed. Examples of transfer elements can be grippers, suction conveyors or other systems configured to take the dose from the separating (cutting) element and transfer it to a mold, where it is deposited before compressing it. In other words, the metering unit provides a pick-up and positioning system, more known as a pick-and-place device, which is not provided in the case of injection instead, as it is not necessary.

[0023] In one or more embodiments, the molding machine includes an actuator assembly configured to compress each charge so that it occupies the molding space of a respective mold. In a compression machine, the actuator assembly includes a hydraulic or mechanical actuator that moves the mold halves toward and away from each other.

[0024] More particularly, in one embodiment, the molding machine is a rotational compression molding machine or an injection compression molding machine.

[0025] In at least one embodiment, the extrusion screw is a barrier screw that defines a feed section and a melt section spaced apart from each other along the longitudinal axis. More specifically, a barrier screw refers to a screw having a single thread in a first section of the screw near the inlet (to define a single first channel for receiving plastic pellets from a hopper), where the thread bifurcates to define a second channel in addition to the first channel. Thus, the thread defines two separate channels (forming the feed section and the melt section): one for pellets that have not yet been plasticized and one for the plasticized melt. Near the beginning of the barrier screw, the melt channel is smaller and the pellet channel is larger; then, proceeding along the axis, the melt channel becomes larger and the pellet channel becomes smaller. This change in channel size can be determined by a change in the pitch of the thread or by a change in the diameter of the core. Thus, in the latter case, the core has a first section with a first area and a second section longitudinally spaced from the first section and having a second area larger than the first area.

[0026] An example of a barrier screw is described in patent document U.S. Pat. No. 6,705,752 B2, which is incorporated herein by reference, and it is understood that all of the features of the barrier screw in patent document U.S. Pat. No. 6,705,752 B2 may be applied to the screw of this embodiment.

[0027] In at least one embodiment, the cylinder includes a groove on its inner surface, the groove extending longitudinally and facing the melting section of the screw. Preferably, the screw is helical. In other embodiments, the groove may be configured as a ring. Preferably, the groove is disposed transversely to the thread of the screw. Thus, the direction of the groove is opposite to the direction of rotation of the screw.

[0028] It should be noted that extruders such as those described in this disclosure (especially those including a barrier screw and grooves inside the barrel) allow for a lower temperature of the outflowing melt to be obtained with the same degree of plasticization. More specifically, the grooves provide a reduced friction path for the melt, which can reduce the melt temperature and put less strain on the screw. This is preferable because it means that less time is needed to cool the molded object. Lower molding temperatures also have the advantage of reducing the shrinkage of the material during cooling.

[0029] Preferably, the groove comprises multiple beginnings, ie, three or more ends.

[0030] Preferably, the grooves on the cylinder also extend to the part of the cylinder facing the feed zone of the screw. More particularly, the grooves may be helical and face both the feed zone and the melt zone.

[0031] Preferably, the depth of the grooves decreases from the inlet to the outlet. The grooves help reduce friction (and therefore the mechanical force required by the screw) when the melt (or small-sized pellets) pass from the feed section to the melting section, and also prevent the pellets from sliding on the inner wall of the cylinder and rotating together with the screw. In the inlet zone, the grooves must be larger in size because the mass of the pellets rotating relative to the cylinder is larger.

[0032] In at least one embodiment, the extrusion cylinder includes a plurality of grooves formed on its inner surface, the plurality of grooves extending (at least partially) longitudinally and facing the melt section of the screw.

[0033] In one embodiment, the cylinder includes a plurality of longitudinal grooves parallel to the longitudinal axis and fabricated on the inner surface of the cylinder, facing the melting section of the screw.

[0034] In one embodiment, the extruder includes a cooler, which is located in the starting zone of the cylinder (near the inlet). Preferably, the cooler is controlled.

[0035] In one embodiment, the extruder includes a mixer, which is located at the end of the extruder near the exit.

[0036] The pellets are fed from a hopper into the feed section of the cylinder, and preferably there is no eccentric widening in the start zone of the cylinder which receives the pellets from the hopper.

[0037] In one embodiment, the extruder includes a pressing device configured to move the molten polymeric material delivered by the screw to make it available to a molding machine for creating the polymeric object.

[0038] In one embodiment, the pressing device includes a pump, in which case the molten polymeric material is continuously fed to a molding machine, preferably a compression molding machine. The function of the pump is to ensure that the material is discharged from the extruder and fed to the molding machine at a constant rate; in fact, without a pump, the flow rate of the material would fluctuate due to the inherent characteristics of the extruder, and in some applications such fluctuations are unacceptable, therefore the use of a pump is preferred.

[0039] In another embodiment, the pressing device includes an injection piston movable by translation within the chamber between an ejection position and an advanced position, in which case the molten polymeric material is intermittently fed to a molding machine, which is preferably an injection molding machine. In either case, the pressing device, if provided, includes a motor (preferably an electric motor) configured to drive the pump or the injection piston.

[0040] However, in one or more embodiments, no pressing device is provided, and the molten material is fed directly from the extruder outlet to a machine that processes the material to create an object or other product. If the machine downstream of the extruder is a compression molding machine, the absence of a pressing device will reduce the dimensional accuracy of the object created, although this reduced accuracy may still be acceptable in some applications. In this regard, if the machine downstream of the extruder is an injection molding machine, the axial movement of the extrusion screw (instead of a pressing device) may serve the function of forcing material out of the extrusion cylinder; in this case, after forcing the charge of material out of the cylinder, the screw must remain in an advanced position until the mold is completely filled, which limits the speed of the machine but may still be acceptable in some circumstances.

[0041] Also, in one embodiment, the machine downstream of the extruder is not a molding machine but a liner, in which case a pressing device is not required. More specifically, a liner is a machine that generates a charge of polymeric material, which is then applied to the inside of a closure (e.g., a crown cap or a bottle lid) to enhance the sealing of the closure. In these machines, variations in the flow rate of the material delivered by the extruder are tolerated. Such liner machines are described, for example, in patent documents WO 04080684, EP 0838326, and WO 2015092644, which are incorporated herein by reference.

[0042] In one embodiment, the system includes a group of sensors, the group of sensors including one or more sensors configured to capture one or more of the following parameters: p1) the pressure of the molten polymer material measured downstream of the pressing device; p2) the absorbed power of the motor that rotates the extrusion screw; p3) extrusion screw speed, p4) Heater absorbed power, p5) Temperature of the molten polymer material; p6) The power absorbed by the motor of the pressing device, p7) Temperature of the extrusion cylinder, p8) the speed at which the pressing device moves the molten polymer material; p9) the pressure measured at the inlet zone of the pressing device; p10) Degree of plasticization inside or at the outlet of the cylinder; p11) The flow rate of molten plastic material at the outlet of the cylinder.

[0043] With regard to parameter p10, it is noted that the degree of plasticization can be measured with a sensor of the type described in patent document WO 2016 / 181361 A1 in the name of the applicant, and it is implicitly understood that all features of sensors for measuring the degree of plasticization can be applied to one or more sensors of the present disclosure.

[0044] Parameters p1-p11 may be monitored parameters for the extruder, the term "monitored parameter" being used to denote a parameter whose value is monitored during operation of the extruder to identify any defects; for example, a sudden change in a monitored parameter may indicate a change in plastic, meaning that the wrong material has been loaded. However, more generally, the term "monitored" refers to any parameter whose value is monitored.

[0045] Parameters p1-p11 may also be recipe parameters for the extruder, and the term "recipe parameter" is used to indicate a parameter that must adopt a predetermined value for any particular type of plastic and / or product produced. Note that a recipe parameter may also be a monitored parameter itself, if it must adopt a predetermined value and the extruder is monitored during operation.

[0046] The system or extruder includes a processing unit (or control unit). Thus, in one embodiment, the sensor system is configured to measure the values ​​of one or more recipe parameters (including any of parameters p1-p11 or a combination thereof). The processing unit is programmed to store target values ​​for the one or more recipe parameters and to provide feedback control to the extruder so as to bring the one or more recipe parameters to and maintain them at the target values. More specifically, feedback control may be provided to the heater by varying the power absorbed by the heater, and / or to the motor driving the screw by varying the rotational speed of the screw, and / or to the pressing device (if provided) by varying the power absorbed by the pressing device motor.

[0047] In one embodiment, the sensor system is configured to measure values ​​of one or more monitored parameters (including any of parameters p1-p11 or a combination thereof). The processing unit is programmed to process a first value of the monitored parameter measured at a first time point and a second value of the monitored parameter measured at a second time point after the first time point, and to generate alert data in response to a comparison between the first and second values ​​of the monitored parameter. More specifically, the alert data is generated when a change in the monitored parameter over a predetermined time period exceeds an acceptable value.

[0048] In one embodiment, the system includes first and second groups of heaters coupled to the cylinder at first and second locations, respectively, and spaced apart longitudinally from one another, and the processing unit is coupled to the first and second groups of heaters and can control them independently of one another, thereby improving the accuracy of control (particularly feedback control to meet the recipe).

[0049] The extruder includes a motor coupled to the screw for absorbing a first electrical power (ie, electrical power that is converted into mechanical power) and thereby transmitting mechanical power to the screw.

[0050] The heater is configured to absorb a second electrical power (ie, electrical power that is converted into thermal power) and thereby transfer the thermal power to the cylinder.

[0051] The monitored parameters may represent a first power (represented by parameter p2) and a second power (represented by parameter p4). In one embodiment, the processing unit is programmed to control the heater (and / or the motor driving the screw) in response to a comparison between the first power and the second power.

[0052] In one embodiment, where the molding machine is a compression or injection compression machine, the first and second mold halves define an undercut when the mold is in a closed position, and the first mold half includes an extruder movable from a retracted position to an ejection position when the mold is in an open position to translate the molded plastic object to facilitate its separation from the first mold half. The mold also preferably includes a pultruder movable along a direction perpendicular to the direction of movement of the first and second mold halves, which is useful for creating the undercut. It is noted that combining the extruder of the present disclosure with a molding machine including an ejector and / or pultruder is particularly inventive because ejection of such an object requires that the object be cooled to a relatively low temperature, and the low temperature of the plastic ensured precisely by this type of extruder as it exits the extruder reduces the required cooling time.

[0053] The present disclosure also provides a method for molding a single object from a plastic material, preferably in a continuous cycle.

[0054] The method includes receiving a plastic material in raw form and producing a flow of the plastic material in a liquid phase through an extruder, preferably made in accordance with one or more aspects of the present disclosure.

[0055] In one or more embodiments, the method includes separating a predetermined amount of plastic material that constitutes each charge from the stream of plastic material.

[0056] In one or more embodiments, the method includes providing a plurality of molds each having first and second mold halves movable relative to one another between an open mold position to allow an object to be removed from the mold and a closed mold position in which the first and second mold halves define an enclosed molding space.

[0057] In one or more embodiments, the method includes compressing each charge in a corresponding one of the molds to cause it to occupy a molding space in the mold.

[0058] Preferably, the extrusion screw is a barrier screw defining a feed compartment and a melt compartment spaced apart from one another along the longitudinal axis, in which connection the method comprises a step of moving the molten plastic material within a groove created on the inner surface of a cylinder, the groove preferably extending in the longitudinal direction and facing the melt compartment of the screw.

[0059] In one embodiment, a method includes capturing values ​​for at least one recipe parameter for an extruder, the at least one recipe parameter selected from one of parameters p1-p11. The method includes storing target values ​​for each of the recipe parameters. The method includes providing feedback control to a heater to bring the recipe parameter to and maintain the target value.

[0060] In one embodiment, a method includes acquiring at least one monitored parameter, the at least one monitored parameter selected from one of parameters p1-p11. The method includes processing a first value of the monitored parameter measured at a first time point and a second value of the monitored parameter measured at a second time point after the first time point. The method includes generating alert data in response to a comparison between the first and second values ​​of the monitored parameter.

[0061] More specifically, in one embodiment, the monitored parameters represent a first power absorbed by the screw motor (parameter p2) and a second power absorbed by the heater (parameter p4). The method includes processing the monitored parameters and controlling the motor driving the heater and / or the screw in response to a comparison between the first power and the second power. For example, the extruder's processing unit can control the heater (and optionally the screw motor) so that the ratio between the first power and the second power is lower than a set value (e.g., less than 30% or 40%), preferably between 20% and 30%. In this regard, it should be noted that the combination of the barrier screw and grooves significantly reduces friction of the material rotated within the cylinder, thus lowering the mechanical power provided by the screw rotation and increasing the heat output delivered by the heater compared to conventional extruders without either a barrier screw or grooves.

[0062] In one embodiment, the molten plastic material traveling within the groove follows a helical path, which is preferably disposed transverse to the flight of the screw, i.e., opposite to the direction of rotation of the screw.

[0063] In one embodiment, the method includes mixing the pressurized streams of molten plastic material with a mixer (located downstream of the cylinder).

[0064] The present disclosure also relates to an extruder. The extruder includes a cylinder extending along a longitudinal axis and having an inlet for receiving pellets of polymeric material and an outlet for discharging molten polymeric material. The extruder may or may not include a groove on its interior. The extruder includes a screw connected to a motor for rotating and driving the screw about the longitudinal axis inside the cylinder and for moving the polymeric material from the inlet to the outlet, the motor connected to the screw for transmitting mechanical power to the screw by absorbing a first electrical power. The screw may or may not be a barrier screw. The extruder includes a heater coupled to the extrusion cylinder and configured to transmit thermal power to the cylinder by absorbing a second electrical power (parameter p4).

[0065] The extruder includes a sensor system configured to capture monitoring parameters, which may represent one or more of the parameters p1 to p11 or a combination thereof. Preferably, the monitoring parameters represent the temperature of the cylinder (parameter p7) and / or the temperature of the molten plastic material at the outlet of the cylinder (parameter p5).

[0066] The extruder includes a processing unit (which may correspond to the processing unit of the object molding system), which is coupled to the sensor system. The processing unit is configured to adjust the second power and / or the first power and / or the power of the pressing device as a function of predetermined criteria and / or specifications received in connection with the created object. For example, the received predetermined criteria and / or specifications may relate to the temperature of the molten plastic material; more specifically, the criteria may specify that the temperature of the molten plastic material should be as low as possible to meet the desired degree of plasticization. Thus, the processing unit makes adjustments in response to or as a function of the temperature of the molten plastic material.

[0067] In one embodiment, the sensor system is configured to capture a monitoring parameter representative of a flow rate of the plastic material at the outlet of the cylinder (parameter p11), and the processing unit is programmed to adjust the first power and / or the power of the pressing device in response to the flow rate of the molten plastic material at the outlet of the cylinder.

[0068] The sensor system is configured to measure the values ​​of one or more recipe parameters (selected from parameters p1 to p11). The processing unit is programmed to store target values ​​for each of the recipe parameters and to perform feedback control (e.g., on a motor driving a heater and / or a screw and / or a motor of a pressing device) to bring the recipe parameter to and maintain the target value. In a first variant, the target value is communicated to the processing unit by a user and is therefore an input data item for the control unit. In another variant, the target value of the recipe parameter is derived by the control unit. More specifically, the target value of the recipe parameter can be derived based on or in response to the adjustment of the second power. Thus, simultaneously with the adjustment of the second power, the processing unit derives the recipe parameter. In other words, the processing unit iterates as a function of requirements specified by the user and / or criteria programmed into the processing unit to identify a configuration that can meet certain specifications, in which the recipe parameters adopt certain values ​​that are saved and used as target values, and in which the heater absorbs a second power, which is set as the adjustment value of the second power.

[0069] The present disclosure also provides a method for extruding a polymeric material. The extrusion is carried out by an extruder constructed according to one or more aspects of the present disclosure. More specifically, the extrusion is carried out by a cylinder and screw that receives pellets of the polymeric material at an inlet of the cylinder, is provided with a heater, and is connected to a motor that rotates and drives the screw inside the cylinder to move the polymeric material from the inlet to the outlet of the cylinder.

[0070] The extrusion method includes acquiring monitored parameters representing the temperature of the extrusion cylinder and / or the temperature of the molten plastic material at the outlet of the extrusion cylinder. The extrusion method also includes processing the monitored parameters and adjusting the temperature of the extrusion cylinder (by adjusting the second power) in response to the temperature of the molten plastic material at the outlet of the extrusion cylinder. The processing unit then adjusts the second power based on the values ​​adopted by the monitored parameters (particularly the temperature of the molten plastic material). In other words, the processing unit iterates as a function of requirements specified by a user and / or criteria programmed into the processing unit to identify a configuration that can meet certain specifications, the specifications and / or criteria being linked to the temperature of the cylinder and the temperature of the molten plastic material. Once a second power that can meet the specifications is identified, the extrusion cylinder is adjusted to remain at the second power.

[0071] In one embodiment, the extrusion method includes the steps of setting target values ​​for recipe parameters, capturing the values ​​of the recipe parameters, and providing feedback control to the heaters to bring and maintain the recipe parameters at the previously stored target values. The target values ​​can be derived by the processing unit itself, in which case specifications and / or standards are converted into target values ​​for the monitored parameters (at a pre-production stage); alternatively, the target values ​​can be set by a user based on prior knowledge and the specifications of the object to be produced. In either case, during the production stage, the extruder is controlled by feedback to ensure that the recipe parameters remain at the target values ​​(previously calculated by the processing unit or set by the user).

[0072] These and other features will become more apparent from the following description of preferred embodiments illustrated by way of non-limiting example in the accompanying drawings. [Brief explanation of the drawings]

[0073] [Figure 1]1 illustrates a system for forming an object according to the present disclosure. [Figure 2] 2 illustrates an extrusion screw for the system of FIG. 1. [Figure 3] 2 illustrates the inside of the cylinder of the extruder of FIG. 1. [Figure 4] 2 illustrates an alternative embodiment of the mold of the molding machine of the system of FIG. 1 in an open configuration. [Figure 5] 5 illustrates the mold of FIG. 4 in a closed configuration. [Figure 6] 10 illustrates another alternative embodiment of the mold of the molding machine of the system of FIG. 1. [Figure 7] 2 shows a functional diagram of a processing unit of an extruder of the system of FIG. 1 in one embodiment thereof. [Figure 8] 2 shows a functional diagram of a processing unit of an extruder of the system of FIG. 1 in another embodiment thereof; [Figure 9] 2 shows a functional diagram of a processing unit of an extruder of the system of FIG. 1 in another embodiment thereof; DETAILED DESCRIPTION OF THE INVENTION

[0074] Referring to the accompanying drawings, the numeral 1 indicates a system for forming an object 8 according to one or more aspects of the present disclosure.

[0075] System 1 includes extruder 2. Extruder 2 includes a cylinder 21 made from an electrically conductive material (e.g., steel) and a screw 22 that rotates inside cylinder 21. Cylinder 21 extends along a longitudinal axis L between an inlet 21A and an outlet 21B. Screw 22 is rotatable about longitudinal axis L. Screw 22 is coupled to a motor 220 that rotates and drives screw 22. Motor 220 preferably includes an electric motor.

[0076] The screw 21 includes a core 221 and threads 222 wound around the core 21. The screw 21 is preferably a barrier screw, and the threads 222 therefore define a feed section 23 and a melt section 24 spaced apart from one another along the longitudinal axis L.

[0077] The extruder 2 includes a loading hopper 25 for feeding pellets to the inlet 21A of the cylinder 21.

[0078] The extruder 2 includes a heater 26 positioned around the cylinder 21. The heater 26 can include a first group of heaters 261 and a second group of heaters 262 spaced apart along the longitudinal axis and controllable independently of each other.

[0079] Preferably, the inner surface of the cylinder 21 facing the screw 22 is provided with a spiral groove 27 .

[0080] System 1 includes a molding machine 3. In the illustrated embodiment, molding machine 3 is a compression molding machine configured to mold objects 8 from respective charges 30 of thermoplastic or polymeric material. More particularly, molding machine 3 includes a plurality of molds 31, each including a first mold half 310 and a second mold half 311, movable along a mold axis between a closed configuration in which they close together to define a molding space 312 in which object 8 is formed, and an open configuration in which first mold half 310 and second mold half 311 are spaced apart.

[0081] In one particular embodiment illustrated, the first mold half 310 may include a central hub 3100 and an outer hub or ejector 3101 surrounding the central hub and movable along the axis of the mold independently of the central hub 3100. The outer hub 3101 is particularly useful for molding an object 8 that forms an undercut. There may also be a puller 3102 that is movable along a direction perpendicular to the axis of the mold and configured to facilitate molding of a portion of the object 8, such as a tie strap of a cap configured to join a tamper-evident ring to the body of the cap.

[0082] The system 1 may also include a metering unit 4 configured to separate from the flow of plastic material a predetermined amount of plastic material forming each charge 30 to be inserted into a corresponding one of the plurality of molds 31 .

[0083] The molding machine 3 is preferably a rotating machine, and therefore includes a rotating table. Preferably, the molding machine 3 includes an upper rotating table including a plurality of first mold halves 310, and a lower rotating table including a plurality of second mold halves 311 that rotate together with the upper rotating table and are movable relative to the corresponding first mold halves 310.

[0084] The system may also include a transfer device 71 configured to receive the charges 30 from the metering unit 4 and supply them to the molding machine 3, and more particularly, the transfer device 71 may include a turntable configured to supply the charges 30 by placing them on the second half mold 311.

[0085] In one embodiment, the transfer device 71 is also configured to remove the formed objects 8 from the forming machine 3 and feed them to the delivery device 72 .

[0086] In one or more embodiments, the extruder 2 also includes a pressing device (not shown). The pressing device is coupled downstream of the cylinder 21 to move the material out of the outlet 21B of the cylinder 21 and discharge it from the extruder 2. In one embodiment, the pressing device includes a pump coupled downstream of the outlet 21B of the cylinder 21. In this embodiment, the pressing device is configured to move the thermoplastic or polymeric material continuously out of the extrusion cylinder, such that the extrusion screw 22 continuously rotates about the longitudinal axis L such that the extrusion cylinder 21 continuously discharges the material through its outlet 21B. This embodiment is preferably used in an extruder configured to feed a compression molding machine 3.

[0087] In another embodiment, the pressing device includes a piston that reciprocates within the cylinder from an ejection position to an advanced position. Inside the cylinder, the piston defines an injection chamber that is fluidly connected to the outlet 21B of the extrusion cylinder 21. More specifically, the extruder 2 includes a first conduit extending from the outlet 21B of the extrusion cylinder 21 and a second conduit extending from the injection chamber, the first and second conduits merging into an outlet conduit configured to discharge the molten polymeric material. The extrusion screw 22 is rotatable about a longitudinal axis L within the extrusion cylinder 21 and can also translate along the longitudinal axis L between the ejection position and the advanced position. Initially, the extrusion screw 22 is in the ejection position, and the pressing device piston is in the advanced position. As the extrusion screw 22 rotates, it also moves along the longitudinal axis L from the ejection position to the forward position. At the same time, the piston of the pressing device moves from the forward position to the ejection position, causing the material exiting the outlet 21B of the extrusion cylinder 21 to enter the injection chamber. At this stage, the material is prevented from flowing into the outlet conduit by the valve blocking the passage. After a predetermined time from when the extrusion screw 22 begins to rotate, the extrusion screw 22 is stopped, and the piston is moved by a specific motor from the ejection position to the forward position. Thus, when the piston moves to the forward position, the piston pushes the molten material into the outlet conduit while filling the injection chamber. At this stage, the valve is open, allowing the material to flow into the outlet conduit. While the piston moves from the ejection position to the forward position, the extrusion screw 22 moves along the longitudinal axis from the forward position to the ejection position. Once all the molten material has been discharged, another cycle begins. This embodiment is used in an extruder configured to supply an injection molding machine.

[0088] The system 1 includes a processing unit 6. The system 1, i.e., the extruder 2, includes a group of sensors 5, which includes a plurality of sensors. The sensors in the group of sensors are configured to capture respective parameters, which may constitute monitoring parameters 52 and / or recipe parameters 51, depending on how they are used by the processing unit 6.

[0089] The group of sensors 5 includes one or more of the following sensors: an outlet pressure sensor configured to measure the pressure of the thermoplastic material at the outlet of the pressing device (if provided), the outlet pressure sensor being connected to an outlet conduit receiving the molten material exiting the cylinder 21 downstream of the pressing device (if provided), the outlet pressure sensor being configured to capture a parameter designated p1 in the present disclosure, a screw power sensor configured to measure the power absorbed by the electric motor 220 driving the screw 22, the screw power sensor being coupled to the motor 220 and configured to capture the parameter indicated in the present disclosure as p2; a screw speed sensor configured to measure the rotational speed of the screw 22, the screw speed sensor being coupled to the screw 22, the screw speed sensor being configured to capture the parameter indicated in p3 of this disclosure; a heater 26 power sensor configured to measure the power absorbed by the heater 26, the heater power sensor being coupled to the heater 26, the heater 26 power sensor being configured to capture the parameters indicated in p4 of this disclosure; a molten material temperature sensor configured to measure the temperature of the molten polymeric material at the outlet 21B of the cylinder 21 of the extruder 2, the molten material temperature sensor being coupled to an outlet conduit receiving the molten material exiting the cylinder 21, the molten material temperature sensor being configured to capture the parameters indicated in p5 of the present disclosure; - a pressing device power sensor configured to measure the power absorbed by the pressing device (if provided), the pressing device power sensor being coupled to a motor driving the pump if the pressing device comprises a pump, or to a motor driving the piston if the pressing device comprises a piston movable inside a cylinder, the pressing device power sensor being configured to capture the parameters indicated in p6 of this disclosure, a cylinder 21 temperature sensor configured to measure the temperature of the cylinder 21, the cylinder 21 temperature sensor being coupled to the cylinder 21, the cylinder 21 temperature sensor being configured to capture the parameters indicated in p7 of this disclosure; - a pressing device speed sensor configured to measure the speed at which the pressing device (if provided) moves the molten plastic material, the pressing device speed sensor being coupled to the pump if the pressing device includes a pump, or to the piston if the pressing device includes a piston movable inside a cylinder, the pressing device speed sensor being configured to capture the parameters indicated on page 8 of this disclosure; an inlet pressure sensor configured to measure the pressure of the molten material at the inlet of the pressing device (if provided), the inlet pressure sensor being connected to a conduit receiving the molten material from the outlet 21B of the cylinder 21 upstream of the pressing device (i.e. upstream of the pump if a pump is provided or upstream of the connection point between the conduit connected to the outlet 21B and the conduit connected to the injection chamber if a slidable piston is provided in the cylinder), the inlet pressure sensor being configured to capture the parameters indicated in p9 of this disclosure, a plasticization sensor configured to capture a parameter representative of the degree of plasticization inside the cylinder 21 or at its outlet 21B, the plasticization sensor being configured to capture the parameter indicated in p10 of this disclosure; - A flow sensor for the molten plastic material at the outlet 21B of the cylinder 21, configured to measure the flow rate of the plastic material at the outlet 21B of the cylinder 21, for example the molten plastic material flow sensor may be associated with the pressing device (if provided), the flow sensor being configured to capture the parameters indicated on p11 of this disclosure.

[0090] The processing unit 6 may operate according to a first operating mode, which is illustrated by way of example in FIG.

[0091] In the first operating mode, the processing unit 6 receives target values ​​50 of recipe parameters 51 from the memory 61. The recipe parameters 51 can be selected from the parameters indicated by p1 to p11, and preferably include the temperature of the cylinder 21, the speed of the screw 22, and the pressure at the outlet of the pressing device (if provided). The target values ​​50 can be stored in the memory 61 by a skilled operator who empirically determines the target values ​​50 as a function of product specifications and personal knowledge. For example, the product specifications can include the type of object 8 to be produced, a specific productivity (i.e., objects produced per hour), and a required specific quality, where the productivity and type of object affect the flow rate of the molten plastic material at the outlet, and the required quality affects the temperature and degree of plasticization at the extruder outlet. As a function of these specifications and personal knowledge, the skilled operator can determine the target values ​​50 of the recipe parameters 51, such as the temperature of the cylinder 21 (parameter p7), the speed of the screw 22 (parameter p3), and / or the pressure at the outlet of the pressing device (parameter p1), if provided. The processing unit 6 also receives recipe parameter values ​​51 measured by the group of sensors 5 and provides feedback control to the extruder 2 to maintain the recipe parameter values ​​51 at their respective target values ​​50. For example, during feedback control, the processing unit 6 may act on a first power P01 absorbed by the motor 220 of the screw 22 and / or a second power P02 absorbed by the heater 26. The processing unit 6 may also receive monitoring parameters 52 selected from the parameters denoted p1 to p11 from the group of sensors 5 and may generate alarm data 53 as a function of the monitoring parameters 52; for example, if the monitoring parameters 52 undergo an unusual variation, the processing unit may generate alarm data 53 indicating a possible incorrect loading of plastic material into the loading hopper 25.

[0092] The processing unit 6 may operate according to a second operating mode, which is illustrated by way of example in FIG.

[0093] In a second operating mode, the processing unit 6 receives specifications 54 for the objects 8 to be produced from the memory 61, and the processing unit 6 is further programmed according to certain criteria (or algorithms) 55. The specifications 54 may include the type of object 8 to be produced, a certain productivity (i.e., objects produced per hour) and a certain quality required. The criteria 55 may include, for example, the relationship between productivity and the flow rate of the molten plastic material, the relationship between the quality of the object 8 and the temperature and degree of plasticization of the molten plastic material (in particular, a low temperature of the molten plastic material results in good quality and meets a sufficient degree of plasticization). In this operating mode, the specifications 54 are processed by the processing unit based on the given criteria 55, rather than by a skilled operator. During the preparation stage of production, the processing unit 6 acts on certain control parameters (such as the first power P01 absorbed by the motor 220 of the screw 22 and / or the second power P02 absorbed by the heater 26) to identify a configuration that meets the specifications 54. In fact, the temperature at the outlet of the extruder 2 (which affects the quality of the product 8) depends mainly on the second power P02 absorbed by the heater 26 (which in turn depends on the friction generated by the rotation of the screw 22 and the heat loss through the cylinder 21), and the flow rate of the processed plastic material (which affects productivity) depends mainly on the first power P01 absorbed by the motor 220 that drives the screw 22. During these operations, the processing unit 6 can use artificial intelligence methods. Furthermore, during the preparation stage of production, the processing unit 6 receives monitoring parameters 52 and can also operate on the control parameters as a function of the monitoring parameters 52. More specifically, by capturing the monitoring parameters 52, the processing unit 6 confirms that the identified configuration efficiently meets the specifications 54. Thus, the monitoring parameters 52 are used by the processing unit 6 during the pre-production stage to identify configurations that meet the specifications 54 .

[0094] Once a configuration that meets specifications 54 is identified, a production phase begins during which processing unit 6 maintains that configuration, and to maintain it, processing unit 6 may operate by feedback on the same control parameters or other parameters (e.g., monitored parameters 52). Again, during the production phase, processing unit 6 may receive monitored parameters 52 measured by the group of sensors 5 and may generate alarm data 53 as a function of monitored parameters 52.

[0095] The processing unit 6 may operate according to a third operating mode, which is illustrated by way of example in FIG.

[0096] In the third operating mode, similar to the second operating mode, the processing unit 6 receives specifications 54 for the object 8 to be produced from the memory 61. Furthermore, the processing unit 6 is programmed according to certain criteria (or algorithms) 55. The specifications 54 may include the type of object 8 to be produced, a certain productivity (i.e., objects produced per hour), and a certain required quality. The criteria 55 may include, for example, the relationship between productivity and the flow rate of the molten plastic material, or the relationship between the quality of the object 8 and the temperature and degree of plasticization of the molten plastic material (especially low temperatures of the molten plastic material result in good quality and a sufficient degree of plasticization). In this operating mode, the specifications 54 are also processed by the processing unit 6 based on the given criteria 55, rather than by a skilled operator. More specifically, the processing unit 6 includes a first module 62 and a second module 63. The first module 62 is used in the preparation stage of production, and the second module 63 is used in the production stage while the object 8 is being produced. In the preparation stage of production, the first module 62 receives the specifications 54 and derives target values ​​50 of the recipe parameters 51 as a function of the specifications 54 and criteria 55, for example the target values ​​50 can be derived through successive iterative calculations until the specifications 54 are met. Again, the recipe parameters 51 can be selected from the parameters indicated by p1 to p11, and preferably the recipe parameters 51 include the temperature of the cylinder 21, the speed of the screw 22 and the pressure at the outlet of the pressing device (if provided). Next, during the production phase, the second module 63 receives the target values ​​50 derived from the first module 62 and the recipe parameters 51 measured from the group of sensors 5, and then, in the same way as in the first operating mode, the second module 63 performs feedback control to maintain the recipe parameters 51 at their respective target values ​​50, more specifically, the second module 63 controls the first power P01 absorbed by the motor 220 of the screw 22 and the second power P02 absorbed by the heater 26 so as to maintain the recipe parameters 51 at their respective target values ​​50.

[0097] Furthermore, in the pre-production stage, the first module 62 receives the first monitoring parameters 52A and can also derive the target values ​​50 as a function of the first monitoring parameters 52A, more particularly, by capturing the first monitoring parameters 52A, the first module 62 verifies that the target values ​​50 effectively meet the specifications 54. Thus, the first monitoring parameters 52A are used by the processing unit 6 in the pre-production stage to iteratively derive the target values ​​50.

[0098] During the production stage, the second module 63 may receive the second monitored parameter 52B and may generate the alarm data 53 as a function of the value adopted by the second monitored parameter 52B.

[0099] The following paragraphs, listed alphabetically for reference, are non-limiting example embodiments illustrating the present invention.

[0100] A. An extruder (2) for polymeric materials, - a cylinder (21) extending along a longitudinal axis (L) and having an inlet (21A) for receiving pellets of polymeric material and an outlet (21B) for discharging molten polymeric material; - a screw (22) connected to a motor for rotating and driving the screw (22) about its longitudinal axis (L) inside the cylinder (21) and for moving the polymeric material from the inlet (21A) to the outlet (21B), the motor being connected to the screw (22) for absorbing a first electrical power (P1) to transmit mechanical power to the screw (22); a heater (26) coupled to the extrusion cylinder (21) and configured to absorb a second electrical power (P2) and thereby transfer thermal power to the cylinder (21); a sensor system (5) configured to capture a monitoring parameter (52) representative of the temperature of the molten plastic material at the outlet (21B) of the cylinder (21); - a processing unit (6) coupled to the sensor system (5); an extruder (2) including:

[0101] A1. The extruder of paragraph A, wherein the processing unit is programmed to adjust the second power (P2) in response to a temperature of the molten plastic material.

[0102] A2. The extruder of paragraph A or A1, wherein the monitored parameters also represent the temperature of the cylinder (21).

[0103] A3. An extruder described in any one of paragraphs A to A2, wherein the sensor system (5) is configured to capture a monitoring parameter (52) representative of the flow rate of the molten plastic material at the outlet (21B) of the cylinder (21).

[0104] A4. An extruder described in any one of paragraphs A to A3, wherein the sensor system (5) is configured to measure the value of the recipe parameter (51), and the processing unit (6) is programmed to store a target value (50) of the recipe parameter and control the heater (26) to bring the recipe parameter (51) to and maintain the target value (50), and the target value (50) of the recipe parameter is derived by the processing unit (6) based on adjustments to the second power (P2) and / or specifications for the object to be created.

[0105] A5. An extruder described in any one of paragraphs A to A4, wherein the monitoring parameter (52) represents a degree of plasticization of the plastic material inside the cylinder (21), and the processing unit (6) is programmed to adjust the first and / or second power (P1, P2) in response to the degree of plasticization of the plastic material inside the cylinder (21).

[0106] A6. An extruder described in any one of paragraphs A-A5, wherein the recipe parameter or monitoring parameter represents the degree of plasticization of the plastic material inside the cylinder and / or the temperature of the molten plastic material at the outlet of the extruder.

[0107] A7. An extruder described in any one of paragraphs A to A6, including a pressing device (5) configured to move the molten polymeric material supplied by the extrusion screw (3) to make it available to a molding machine for creating a polymeric object, and the monitoring parameter (52) is based on the pressure of the molten polymeric material measured downstream of the pressing device (5).

[0108] A8. An extruder described in any one of paragraphs A to A7, wherein the screw (22) is a barrier screw defining a feed section (23) and a melt section (24) spaced apart from one another along the longitudinal axis (L), and the cylinder (21) includes a groove (27) on its inner surface extending longitudinally and facing the melt section (24) of the screw (22).

[0109] A8.1. The extruder of paragraph A8, wherein the groove (27) is spiral.

[0110] A8.2. The extruder of paragraph A8 or A8.1, wherein the helical grooves (27) are disposed transversely to the threads (222) of the screw (22).

[0111] A8.3. The extruder of any of paragraphs A8-A8.2, wherein the groove (27) includes multiple initiations.

[0112] A8.4. The extruder of any of paragraphs A8 to A8.3, wherein the depth of the groove (27) gradually decreases from the inlet (21A) to the outlet (21B).

[0113] A8.- A sensor system (5) configured to measure the values ​​of recipe parameters (51) for the extruder (2), a processing unit (6) programmed to store target values ​​(50) of recipe parameters and to provide feedback control to the heater (26) to bring the recipe parameters (51) to and maintain the target values ​​(50); The extruder of any of paragraphs A-A8.4, comprising:

[0114] A9. An extruder described in any one of paragraphs A to A8, wherein the sensor system (5) is configured to measure a value of a monitored parameter (52) for the extruder (2), and the processing unit (6) is programmed to process a first value of the monitored parameter (52) measured at a first time point and a second value of the monitored parameter (52) measured at a second time point after the first time point, and to generate alarm data (53) in response to a comparison between the first value and the second value of the monitored parameter (52).

[0115] A10. An extruder described in any one of paragraphs A8 to A9, comprising first and second groups of heaters (26) coupled to the cylinder at first and second positions, respectively, and spaced apart from one another in the longitudinal direction, wherein the processing unit (6) is coupled to the first and second groups of heaters (261, 262) and controls them independently of one another.

[0116] A11. The extruder (2) includes a motor coupled to the screw to transmit mechanical power to the screw by absorbing a first electric power (P1); the heater (26) is configured to absorb a second power (P2) and thereby transfer heat power to the cylinder (21); the extruder (2) includes a sensor system (5) configured to capture monitoring parameters (52) representative of the first power (P1) and the second power (P2); The extruder of any one of paragraphs A-A10, wherein the extruder (2) includes a processing unit (6) coupled to the sensor system (5) and programmed to control the heater (26) in response to a comparison between the first power (P1) and the second power (P2).

[0117] B. A continuous cycle system (1) for molding a single object from a plastic material, comprising: - the extruder of any one of paragraphs A to A12; - a molding machine (3) designed to receive a flow of molten plastic material from an extruder (2), a plurality of molds (31) each having first and second mold halves (310, 311) movable relative to one another between an open mold position to allow removal of an object from the mold (31) and a closed mold position in which the first and second mold halves (310, 311) define an enclosed molding space (312); Including molding machines (3) A continuous cycle system (1).

[0118] B1. The system (1) described in paragraph B, including a metering unit (4) configured to separate a predetermined amount of plastic material forming each charge from the flow of plastic material, the amount being inserted into a corresponding mold of the plurality of molds.

[0119] B2. The system (1) of paragraph B or B1, including an actuator assembly configured to compress each charge so that it occupies the molding space (312) of the respective mold (31).

[0120] B3. The system (1) described in any one of paragraphs B to B2, wherein the molding machine (3) is a compression molding machine, an injection compression molding machine, or an injection molding machine.

[0121] B4. The system described in paragraph B3, wherein the first and second mold halves (310, 311) define an undercut when the mold (31) is in a closed position, and the first mold half (310) includes an ejector (3101) movable from a retracted position to an ejection position to translate the molded plastic object to facilitate its separation from the first mold half (310) when the mold (31) is in an open position.

[0122] C. A method of extruding a polymeric material by means of a cylinder, the cylinder receiving pellets of polymeric material at its inlet and provided with a heater, and a screw, the screw connected to a motor which rotates and drives the screw inside the cylinder to move the polymeric material from the inlet to the outlet of the cylinder, - capturing monitoring parameters representative of the temperature of the extrusion cylinder and / or the temperature of the molten plastic material at the outlet of the extrusion cylinder, - processing the monitored parameters and adjusting the temperature of the extrusion cylinder in response to the temperature of the molten plastic material at the outlet of the extrusion cylinder. A method comprising:

[0123] C1.- setting the target values ​​of the recipe parameters; - capturing values ​​of recipe parameters; - providing feedback control to the heater to bring and maintain the recipe parameters at previously stored target values; The method of paragraph C, further comprising: [Prior art documents] [Patent documents]

[0124] [Patent Document 1] International Publication No. 2018 / 025150A1 Brochure [Patent Document 2] International Publication No. 2011161649A1 Brochure [Patent Document 3] International Publication No. 2019207420A1 Brochure [Patent Document 4] European Patent Application Publication No. 2585273A1 [Patent Document 5] International Publication No. 2018025100 Brochure [Patent Document 6] German Patent Application No. 10130759A1 and [Patent Document 7] European Patent No. 1194278B1 [Patent Document 8] Chinese Patent Application Publication No. 103496147A [Patent Document 9] U.S. Patent No. 6705752B2 [Patent Document 10] International Publication No. 04080684 Brochure [Patent Document 11] European Patent No. 0838326 [Patent Document 12] International Publication No. 2015092644 Brochure [Patent Document 13] International Publication No. 2016 / 181361A1 Brochure

Claims

1. 1. A continuous cycle system for molding a single object from a plastic material, comprising: an extruder designed to receive plastic material in raw form and to deliver a stream of plastic material in liquid phase, a cylinder extending along a longitudinal axis between an inlet and an outlet; a screw rotating about the longitudinal axis inside the cylinder, the screw having a core and threads coupled to the exterior of the core; a heater coupled to the cylinder an extruder including a compression moulding machine designed to receive the flow of plastic material from the extruder, a plurality of moulds each having first and second mould halves movable relative to one another between an open position to allow removal of the object from the mould and a closed position in which the first and second mould halves define an enclosed moulding space; a metering unit configured to separate a predetermined amount of plastic material forming each charge from the flow of plastic material, the metering unit being inserted into a corresponding one of the plurality of molds; an actuator assembly configured to compress each charge so that it occupies the molding space of the corresponding mold; Compression molding machine including wherein the screw of the extruder is a barrier screw defining a feed section and a melt section spaced apart along the longitudinal axis, and the cylinder includes a longitudinally extending groove on an inner surface thereof facing the melt section of the screw, the continuous cycle system comprising: a sensor system configured to measure values ​​of recipe parameters for said extruder and to measure values ​​of monitoring parameters for said extruder, said sensor system comprising one or more sensors configured to capture one or more of the following parameters: the speed of said screw, the temperature of said cylinder; a processing unit programmed to store a target value for the recipe parameter and to provide feedback control to the heater to bring the recipe parameter to and maintain the target value, the processing unit being programmed to process a first value of the monitored parameter measured at a first time point and a second value of the monitored parameter measured at a second time point after the first time point, and to generate alarm data in response to a comparison between the first and second values ​​of the monitored parameter; - first and second groups of heaters coupled to the cylinder at first and second locations, respectively, and spaced apart longitudinally from one another, the processing unit being coupled to the first and second groups of heaters to control them independently of one another; A continuous cycle system comprising:

2. The system of claim 1 , wherein the groove is helical and disposed transversely to the threads of the screw.

3. The system of claim 1 or 2, wherein the groove includes multiple initiations.

4. The system of any one of claims 1 to 3, wherein the depth of the groove gradually decreases from the inlet to the outlet.

5. The sensor system may measure one or more of the following parameters: - the absorbed power of the motor that rotates said screw, - the absorbed power of said heater, - the temperature of the molten polymeric material, - the degree of plasticization inside or at the outlet of said cylinder, - the flow rate of the molten plastic material at the outlet of said cylinder, The system of any one of claims 1 to 4, comprising one or more sensors configured to capture one or more of:

6. the extruder includes a motor coupled to the screw for absorbing a first electrical power to transmit mechanical power to the screw; the heater is configured to absorb a second electrical power to transfer thermal power to the cylinder; the extruder includes a sensor system configured to capture monitoring parameters representative of the first power and the second power; 6. The system of claim 1, wherein the extruder includes a processing unit coupled to the sensor system and programmed to control the heater in response to a comparison between the first power and the second power.

7. 7. The system of claim 1, wherein the compression molding machine is a compression molding machine or an injection-compression molding machine, the first and second mold halves define an undercut when the mold is in the closed position, and the first mold half includes an ejector movable from a retracted position to an ejection position when the mold is in the open position to translate the molded plastic object to facilitate its separation from the first mold half.

8. 8. The system according to claim 1, wherein the metering unit includes a separation element configured to separate a plurality of pasty charges from the flow of plastic material, and a transfer element configured to pick up each pasty charge from the separation element, transfer the pasty charge to the vicinity of the plurality of moulds, and deposit the pasty charge in a corresponding one of the plurality of moulds.

9. 9. The system of any one of claims 1 to 8, wherein the processing unit is configured to receive specifications for the single object, the specifications including one or more of the following: a type of the object to be produced, a particular productivity and a particular quality required, and the processing unit is programmed to process the specifications according to particular criteria.

10. 10. The system of claim 9, wherein the processing unit includes a first module and a second module, the first module configured to receive the specifications and programmed to derive target values ​​for recipe parameters as a function of the specifications and criteria, and the second module configured to receive the target values ​​derived from the first module and the recipe parameters measured from the sensor system and perform feedback control to maintain the recipe parameters at their respective target values.

11. 11. The system of claim 10, wherein the first module is configured to receive a first monitored parameter and is programmed to derive the target value also as a function of the first monitored parameter, and the second module is configured to receive a second monitored parameter and is programmed to generate alert data as a function of a value adopted by the second monitored parameter.

12. The first module is programmed to derive target values ​​through iterative calculations, and the recipe parameters are one or more of the following: - the speed of said screw, the temperature of said cylinder, 12. The system of claim 10 or 11, wherein the system is one or more of:

13. The extruder comprises a pressing device configured to move the plastic material from the screw to the compression molding machine, the pressing device including a pump and a motor configured to drive the pump, and the recipe parameters are one or more of the following: - the pressure of the molten polymeric material measured downstream of said pressing device, - the absorbed power of the motor that rotates said screw, - the absorbed power of said heater, - the temperature of said molten polymeric material, - the power absorbed by the motor of the pressing device, - the speed at which the pressing device moves the molten polymeric material; - the pressure measured at the inlet zone of said pressing device, - the degree of plasticization inside or at the outlet of said cylinder, the flow rate of molten plastic material at the outlet of the cylinder, The system of claim 12, wherein the one or more of:

14. 1. A continuous cycle system for molding a single object from a plastic material, comprising: an extruder designed to receive plastic material in raw form and to deliver a stream of plastic material in liquid phase, a cylinder extending along a longitudinal axis between an inlet and an outlet; a screw rotating about the longitudinal axis inside the cylinder, the screw having a core and threads coupled to the exterior of the core; a heater coupled to the cylinder an extruder including a compression moulding machine designed to receive the flow of plastic material from the extruder, a plurality of moulds each having first and second mould halves movable relative to one another between an open position to allow removal of the object from the mould and a closed position in which the first and second mould halves define an enclosed moulding space; a metering unit configured to separate a predetermined amount of plastic material forming each charge from the flow of plastic material, the metering unit being inserted into a corresponding one of the plurality of molds; an actuator assembly configured to compress each charge so that it occupies the molding space of the corresponding mold; Compression molding machine including wherein the screw of the extruder is a barrier screw defining a feed section and a melt section spaced apart along the longitudinal axis, and the cylinder includes a longitudinally extending groove on its inner surface facing the melt section of the screw; the extruder includes a pressing device configured to move the plastic material from the screw to the compression molding machine, the pressing device including a pump and a motor configured to drive the pump, and the continuous cycle system includes: a sensor system configured to measure values ​​of recipe parameters for said extruder and to measure values ​​of monitoring parameters for said extruder, said sensor system comprising one or more sensors configured to capture one or more of the following parameters: the speed of said screw, the temperature of said cylinder; a processing unit programmed to store a target value for the recipe parameter and to provide feedback control to the heater to bring the recipe parameter to and maintain the target value, the processing unit being programmed to process a first value of the monitored parameter measured at a first time point and a second value of the monitored parameter measured at a second time point after the first time point, and to generate alarm data in response to a comparison between the first and second values ​​of the monitored parameter; - first and second groups of heaters coupled to the cylinder at first and second locations, respectively, and spaced apart longitudinally from one another, the processing unit being coupled to the first and second groups of heaters to control them independently of one another; A continuous cycle system comprising:

15. The sensor system may measure one or more of the following parameters: - the pressure of the molten polymeric material measured downstream of said pressing device, - the absorbed power of the motor that rotates said screw, - the absorbed power of said heater, - the temperature of said molten polymeric material, - the power absorbed by the motor of the pressing device, - the speed at which the pressing device moves the molten polymeric material; - the pressure measured at the inlet zone of said pressing device, - the degree of plasticization inside or at the outlet of said cylinder, the flow rate of molten plastic material at the outlet of the cylinder, 15. The system of claim 14, comprising one or more sensors configured to capture one or more of:

16. 1. A method for molding a single object from a plastic material in a continuous cycle, comprising: receiving a plastic material in raw form and producing a flow of plastic material in a liquid phase through an extruder, the extruder including a cylinder extending along a longitudinal axis, a screw connected to a motor for driving the screw in rotation about the longitudinal axis inside the cylinder, the screw having a core and threads coupled to an exterior of the core, and a heater coupled to the cylinder; - separating a predetermined amount of plastic material constituting each charge from said flow of plastic material; - providing a plurality of moulds each having a first and second mould half, said first and second mould half being movable relative to one another between an open mould position to allow removal of said object from said mould, and a closed mould position in which said first and second mould half delimit an enclosed moulding space; compressing each charge in a corresponding one of the plurality of molds so that the charge occupies the molding space of the mold; wherein the screw of the extruder is a barrier screw defining a feed section and a melt section spaced apart from one another along the longitudinal axis, the method comprising the step of moving molten plastic material within a groove created on an inner surface of the cylinder extending longitudinally and facing the melt section of the screw; the extruder includes first and second groups of heaters coupled to the cylinder at first and second locations, respectively, and spaced apart longitudinally from one another; The method comprises: - measuring the values ​​of recipe parameters for the extruder, said parameters being one or more of the following: the speed of the screw, the temperature of the cylinder, - storing target values ​​of said recipe parameters; providing feedback control to the heater to bring the recipe parameter to and maintain the target value; - measuring a monitoring parameter; processing a first value of said monitored parameter measured at a first time point and a second value of said monitored parameter measured at a second time point after said first time point; generating alert data in response to a comparison between the first and second values ​​of the monitored parameter; - controlling the first and second groups of heaters independently of each other; A method comprising:

17. - capturing monitoring parameters representative of a first power absorbed by the motor of the screw and a second power absorbed by the heater; processing the monitored parameters and controlling the heater in response to a comparison between the first power and the second power; 17. The method of claim 16, further comprising:

18. 18. A method according to claim 16 or 17, wherein the molten plastic material moving within the groove follows a helical path extending transversely to the threads of the screw.

19. A method according to any one of claims 16 to 18, comprising the step of mixing the streams of plastic material with a mixer.

20. 20. A method according to any one of claims 16 to 19, wherein the separating step comprises separating a plurality of pasty charges from the flow of plastic material through a separating element, the method comprising the step of transporting the plurality of pasty charges, a transporting element picking up each pasty charge from the separating element, transporting the pasty charge adjacent to a mould of the plurality, and depositing the pasty charge in a corresponding mould of the plurality.

21. 1. An extruder for polymeric materials, comprising: a cylinder extending along a longitudinal axis, the cylinder having an inlet for receiving pellets of polymeric material and an outlet for discharging molten polymeric material; a screw connected to a motor for driving the screw in rotation about the longitudinal axis inside the cylinder and for moving the polymeric material from the inlet to the outlet, the motor being connected to the screw for absorbing a first electrical power to transmit mechanical power to the screw, the screw being a barrier screw defining a feed compartment and a melt compartment spaced apart from one another along the longitudinal axis, the cylinder including a groove on its inner surface extending longitudinally and facing the melt compartment of the screw; a heater coupled to said cylinder and configured to absorb a second electrical power to transfer thermal power to said cylinder; a sensor system configured to capture monitoring parameters representative of the temperature of the cylinder and the temperature of the molten polymeric material at the outlet of the cylinder, the sensor system being configured to measure values ​​of recipe parameters for the extruder and comprising one or more sensors configured to capture one or more of the following parameters: the speed of the screw, the temperature of the cylinder; a processing unit coupled to the sensor system and programmed to adjust the second power in response to a temperature of the molten polymeric material, the processing unit being programmed to store a target value for the recipe parameter and control the heater to bring the recipe parameter to and maintain it at the target value, to derive the target value for the recipe parameter based on the adjustment of the second power, to process a first value of the monitored parameter measured at a first time point and a second value of the monitored parameter measured at a second time point after the first time point, and to generate alarm data in response to a comparison between the first and second values ​​of the monitored parameter; a heater comprising first and second groups of heaters coupled to the cylinder at first and second locations, respectively, and spaced apart longitudinally from one another, the processing unit being coupled to the first and second groups of heaters to control them independently of one another; An extruder including:

22. - the sensor system is configured to capture a monitoring parameter representative of the flow rate of the molten polymeric material at the outlet of the cylinder; 22. The extruder of claim 21, wherein the processing unit is programmed to adjust the first power in response to the flow rate of the molten polymeric material at the outlet of the cylinder.

23. 23. The extruder of claim 21 or 22, wherein the monitored parameter represents a degree of plasticization of the polymeric material inside the cylinder, and the processing unit is programmed to adjust the first and / or second power in response to the degree of plasticization of the polymeric material inside the cylinder.

24. 1. A method of extruding a polymeric material by means of a cylinder receiving pellets of polymeric material at an inlet thereof and provided with a heater, and a screw connected to a motor that rotates and drives the screw inside the cylinder to move the polymeric material from the inlet toward the outlet of the cylinder, comprising: - capturing monitoring parameters representative of the temperature of the cylinder and of the temperature of the polymeric material at the outlet of the cylinder; - measuring recipe parameters including one or more of the following parameters: the speed of the screw, the temperature of the cylinder; - processing the monitored parameters and adjusting the temperature of the cylinder in response to the temperature of the polymeric material at the outlet of the cylinder; - storing a target value of the recipe parameter and controlling the heater to bring the recipe parameter to and maintain it at the target value, the target value of the recipe parameter being derived by a processing unit based on the temperature of the cylinder; processing a first value of said monitored parameter measured at a first time point and a second value of said monitored parameter measured at a second time point after said first time point; generating alarm data in response to a comparison between the first and second values ​​of the monitored parameter; Including, The method, wherein the heaters include first and second groups of heaters coupled to the cylinder at first and second locations, respectively, and spaced apart longitudinally from one another, and the processing unit is coupled to the first and second groups of heaters to control them independently of one another.

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