HK1247891B - Device and method for feeding molten plastic material into a molding cavity - Google Patents

Description

Apparatus and method for injecting molten plastic material into a mold cavity

Technical Field

The present invention relates to a device and a method for injecting molten plastic material into a mold cavity, wherein the plastic material is loaded in a metered manner into a melting chamber, in which the plastic material can be melted by moving parts of a sonotrode relative to the melting chamber, the movement and activation of the sonotrode causing the molten plastic material to be introduced into a mold cavity communicating with the melting chamber.

Background Art

Document EP2189264 discloses, in particular, a device for melting plastic material by vibrating a sonotrode, the sonotrode being equipped with a portion inserted into a melting chamber, wherein the plastic material is driven from this portion of the sonotrode into the mold cavity by the movement of the portion of the sonotrode inside the melting chamber. This document envisages regulating the energy supplied to the plastic material by vibrating the sonotrode, taking into account the feed characteristics and the amount and/or type of plastic material used, in a manner that combines all these parameters.

Document WO2004024415 describes a device for injecting molten plastic material, in this case using a section comprising a sonotrode that is statically inserted into the melting chamber. This section of the sonotrode is in direct contact with the plastic material and is designed to improve the melt flow characteristics of the plastic material, allowing it to be driven and inserted into the mold cavity in an improved manner.

Document EP2591901 describes an injection device for injecting solid plastic material, which allows providing a controlled dose of granular plastic material by counting and weighing the particles, provides useful information for calibrating a melting device for melting the solid plastic material, and incorporates an ultrasonic generator arranged to act on a chamber loaded by said feeding device.

It is known, for example, from patent application EP1000732, in particular when welding plastic materials, for a sonotrode to have an air channel defined through a portion thereof in order to cool the operating area of said sonotrode.

Summary of the Invention

The present invention relates to a device for injecting molten plastic material into a mold cavity, the device comprising a melting chamber connected to:

- The vibrating part of the ultrasonic generator of an ultrasonic transducer;

a channel for injecting solid plastic material, which can be in granular form, powdered form, in strip format or in another form, and

at least one outlet opening for supplying molten plastic material to the mold cavity;

The apparatus includes translation means for providing relative movement between the sonotrode portion and the melting chamber, adjusting the position of the tip of the sonotrode portion within the melting chamber.

Thus, it is envisaged that the melting chamber can be at least partially filled with the plastic material (known in the art as granules), eg preferably having a substantially uniform particle size distribution, supplied via the feed channel.

Alternatively, other feed systems of different forms specific to solid plastic materials can be envisaged, such as channels, transfer pieces etc.

The sonotrode has a portion that can be inserted into the melting chamber, the insertion being adjustable by the translation device.

The portion of the ultrasonic generator inserted into the melting chamber contacts the solid plastic material disposed therein and facilitates melting thereof by ultrasonic vibrations generated by the ultrasonic transducer and transmitted through the ultrasonic generator portion. For melting the plastic material, vibrations having a frequency between 10 kHz and 50 kHz are considered optimal but not limiting.

A translation device is understood herein to be a device that allows guided axial movement, automatically operated, for example, by connection to an actuator (e.g., a rotary or linear electric motor), an electromagnet, a servo motor, a piston, or other similar actuator, which preferably moves the sonotrode relative to a fixed melting chamber, although movement of the melting chamber relative to the fixed sonotrode is also conceivable. The use of servohydraulic or purely hydraulic actuation is not excluded.

The relative movement between the ultrasonic generator and the melting chamber, as the plastic material in the mold cavity begins to melt, drives the molten plastic material through the outlet hole of the melting chamber to ensure that it is injected into the mold cavity.

The implementation of the proposed invention requires a device for metering molten plastic material into a mold cavity, furthermore having a resistance sensor provided for detecting the resistance to movement, wherein the plastic material metered in the melting chamber through the channel resists the relative movement between parts of the sonotrode and the melting chamber.

The invention also envisages an electronic control device for regulating said translation device based at least on the information provided by said resistance sensor.

The resistance sensor allows the detection of the force exerted by the plastic material in contact with the sonotrode portion against its movement. This measurement allows the fluidity of the plastic material when the sonotrode portion is in contact with it and when it is molten to be known, since the greater the fluidity, the smaller the force resisting the sonotrode movement, and vice versa.

All this information, together with knowledge of the relative position between the sonotrode and the melting chamber, allows the electronic control to know the volume of the melting chamber, which is occupied by the granular or molten plastic material or its fluidity.

The known flow properties of the plastic material also allow the electronic control means to adjust the translation means, adapting the operation of said means to the flow properties of the molten plastic material, achieving improved feeding of the mould cavity.

The resistance sensor can be of many types, as the force can be detected in a variety of ways. By way of non-limiting example, the resistance sensor can detect the power consumption of the translation device when it is electrically actuated, and therefore the work the translation device must do to overcome the resistance of the plastic material. Another example could be a pressure sensor disposed in the sonotrode, booster segment, transducer, or any other part of the vibrating component, or in a support member of the melting chamber, thereby allowing for the detection of vibrations in pressure caused by greater or lesser resistance of the plastic material to the forward movement of the sonotrode portion. An additional non-limiting example is the provision of a pressure sensor to measure the driving hydraulic pressure when the translation device is operated by a hydraulic or pneumatic actuator, which also allows for the detection of vibrations in the force exerted by the plastic material against the forward movement of the sonotrode. Many other examples of resistance sensors can be implemented without modifying the present invention, as will be apparent to those skilled in the art.

The information provided by the resistance sensor is transmitted to an electronic control unit, which controls and regulates the translation device. Based on the information received from the resistance sensor and based on a program implemented in the electronic control unit, the electronic control unit controls the operating parameters of the translation device to produce the correct metered feed of molten plastic material into the mold cavity.

It should be understood that the electronic control device may be as follows, for example, or another equivalent solution, which will be obvious to those skilled in the art:

An electronic device, for example a programmable logic controller or similar (which can be implemented in the form of a circuit or a computing board, equipped with data inputs and outputs), a memory, implementing computing operations; said device can be fed with data from sensors and said computing operations allow providing control commands.

The electronic control unit will include a power supply and data display means, such as a screen, for informing the operator. It may also include means allowing the operator to change the configuration of the electronic control unit, such as a keyboard, buttons, option menus, etc. These means may be local or remote.

According to a preferred embodiment, the device for metering molten plastic material into the mold cavity also includes a feed sensor configured to detect the number of pellets and/or the weight of solid plastic material injected into the melting chamber. This allows accurate metering of the plastic material by weight and by number of pellets, rather than the volume that the pellets will occupy once deposited in the melting chamber, as they may contain bubbles that change their density and because they will be randomly arranged. However, the electronic control unit obtains this information through data provided by the resistance sensor, which allows it to determine when the tip of the sonotrode (whose position is known to the electronic control unit) comes into contact with the solid plastic material. Thus, the metering of the weight of the solid plastic material, the volume, and the number of pellets is completely controlled by the feed sensor, together with the resistance sensor.

Alternatively or additionally, an environmental sensor may be provided for detecting the ambient temperature and/or humidity. The possibility of providing an operational sensor for detecting one or more of the following parameters may also be included:

The relative position of the sonotrode parts with respect to the melting chamber;

The temperature of the ultrasonic generator;

The temperature of the ultrasonic generator part;

The temperature of the melting chamber;

Cavity temperature;

The temperature of the plastic material;

The information acquired by these resistance sensors or by the feed, environmental and/or operating sensors is supplied to an electronic control device which controls the actuators of the device, allowing one or more of the following operating parameters of the device to be adjusted:

Actuation of ultrasonic generator

The relative position of the sonotrode parts with respect to the melting chamber when the sonotrode is activated to vibrate;

The actuation time of the ultrasonic generator;

The vibration frequency of the ultrasonic generator;

The vibration amplitude of the ultrasonic generator;

The relative speed of the ultrasonic generator part with respect to the melting chamber;

The acceleration of the relative motion of the sonotrode parts with respect to the melting chamber;

the pressure exerted on the plastic material contained in the melting chamber by the relative movement of the sonotrode part with respect to the melting chamber;

Optionally, the means for injecting molten plastic material comprises cooling means external to the sonotrode portion, arranged for bringing a coolant fluid into thermal contact with the sonotrode portion, thereby producing cooling.

According to one embodiment, the cooling device comprises a coolant gas diffuser arranged around the outlet of the sonotrode portion in the melting chamber, configured to diffuse coolant gas through the sonotrode portion extracted from the melting chamber. In another embodiment, the cooling device comprises a coolant liquid circuit arranged around at least one portion of the melting chamber, configured to allow coolant liquid to flow therein, cooling at least one portion of the melting chamber in thermal contact with the sonotrode portion.

The actuation of the cooling device may also be controlled by an electronic control device based on data acquired from resistance sensors or feed, environmental and/or operating sensors.

Even if neither the sonotrode section nor the melting chamber includes a heating device, vibration and friction can cause the sonotrode section to heat up. Overheating the sonotrode section can cause the molten plastic material to stick to the section. A cooling cycle is used to prevent this phenomenon.

Adjusting these parameters allows for precise control of the amount of energy applied to the plastic material, as both vibration (frequency and duration) and motion (speed, acceleration, and pressure) are modes of energy application. Excessive energy applied to all or a portion of the plastic material can lead to its degradation; therefore, it is desirable to precisely know the amount and position of the solid plastic material disposed within the melting chamber so that the electronic control unit can precisely adjust the energy applied to achieve proper melting of the plastic material without causing degradation. Therefore, the electronic control unit includes within its programming ranges an indication of the minimum energy required to cause melting of the plastic material, as well as the maximum energy required to cause its degradation, with the ranges being appropriate for the different conditions detected by the various sensors provided.

According to another embodiment, the electronic control device may furthermore have a user interface allowing an operator to input information in said electronic control device about the type of plastic material used and/or the form of the granules, which allows an improved adjustment of the operating parameters.

Furthermore, it is conceivable that the electronic control device has a memory configured with different operating parameter configurations of the device associated with different types of plastic materials and/or different usable granular forms, also allowing the electronic control device to adjust the aforementioned operating parameters based on this information contained in the memory, thereby achieving more precise adjustment based on the information contained in the memory.

According to a preferred embodiment of the device for injecting molten plastic material into a mould cavity, the translation means are electrically driven and the resistance sensor detects the consumption of said translation means during its driving.

The invention also proposes a method for injecting molten plastic material into a mould cavity by means of a device (as described above) provided with a pressure sensor and electronic control means capable of regulating the translation means.

The method comprises the following steps, forming a production cycle:

a) loading metered plastic material into the melting chamber through the channel for injecting plastic material;

b) activating the ultrasonic generator to melt the plastic material;

c) Actuating the translation device to adjust the relative position between the sonotrode portion and the melting chamber, inserting the tip of the sonotrode portion further into the melting chamber and pushing the molten plastic material through the exit orifice into the mold cavity.

The proposed method is characterized in that, before executing step b), a relative position is first established between the sonotrode part and the melting chamber, the tip of the sonotrode part is inserted into the melting chamber until the resistance sensor detects that the plastic material inserted into the melting chamber resists the forward movement of the sonotrode part, thereby detecting contact between the sonotrode part and the plastic material and providing an indication of the volume of the melting chamber occupied by the plastic material. This information is transmitted to the electronic control unit, which regulates the activation of the sonotrode and the actuation of the translation device in step c) based at least on the data provided by the resistance sensor.

This allows the electronic control unit to know the volume of the melting chamber occupied by the granular plastic material, and it allows the vibrations generated by the translation means and the relative position between the sonotrode and said melting chamber to be adjusted according to said information with the aim of applying to the plastic material an energy that will allow it to be melted without degrading it, remaining within predetermined energy ranges included in the electronic control unit.

According to an optional embodiment of the method, the electronic control device can also perform the adjustment of the operating parameters through an environmental sensor and/or an operating sensor based on information provided by the feed sensor. The feed sensor is provided to detect the number of particles and/or the weight of the solid plastic material injected into the melting chamber; the environmental sensor is provided to detect the ambient temperature and/or humidity; and the operating sensor is provided to detect one or more of the following parameters:

The relative position of the sonotrode parts with respect to the melting chamber;

The temperature of the ultrasonic generator;

The temperature of the ultrasonic generator part;

The temperature of the melting chamber;

Cavity temperature.

Using the information provided by these sensors, the electronic control unit is able to more closely regulate operating parameters, achieving improved melting of the plastic material and resulting in molded plastic parts of better quality.

According to an optional embodiment of the method, the electronic control device adjusts one or more of the following operating parameters based at least on the data provided by the resistance sensor:

The relative position of the sonotrode parts with respect to the melting chamber when the sonotrode is activated to vibrate;

The actuation time of the ultrasonic generator;

The vibration frequency of the ultrasonic generator;

The relative movement speed of the ultrasonic generator part relative to the melting chamber:

The acceleration of the relative motion of the sonotrode parts with respect to the melting chamber;

• The pressure exerted on the plastic material contained in the melting chamber by the relative movement of the sonotrode part with respect to the melting chamber.

These parameters determine the amount of energy applied to the plastic material.

Furthermore, it is conceivable that the electronic control device calculates the energy applied to the plastic material by means of the operating parameters and, based on the information acquired by the various sensors and on the basis of the minimum and maximum energy ranges stored in said control device, it calculates the adjustment of said operating parameters so that said applied energy is sufficient to cause the plastic material to melt properly but not sufficient to cause it to degrade.

The electronic control unit thus analyses all the information supplied by the different sensors and determines the adjustment of each parameter, taking into account that the energy applied to the plastic material is suitable to melt it without degrading it, according to the minimum and maximum energy ranges supplied to said electronic control unit by its programming.

According to an additional embodiment, at least one different sensor measures and provides information at different times during the production cycle, and the electronic control unit performs different adjustments of said operating parameters at different times during the production cycle, adjusting them at least according to the information provided by said at least one sensor. Thus, the operating adjustments can be adapted to the changes that occur continuously in the plastic material when receiving said energy, such as its solid or liquid state or its viscosity, for example, so that the adjustments are variable and adaptable during the entire cycle.

It is also provided that the programmable electronic control device is able to control and connect each of the above variables in an isolated manner or temporarily using other methods (scalers, correlation curves, etc.) throughout the duration of the process.

Alternatively, it is also conceivable that, when the electronic control unit determines, using the information provided by at least one of the sensors, that the plastic material has reached a predetermined fluidity, the sonotrode is stopped without necessarily stopping its movement relative to the melting chamber, thereby reducing the energy applied to the plastic material. This allows the fluidization of the plastic material to be stopped at a level considered optimal for its injection into the mold cavity.

Furthermore, when the electronic control unit determines, by means of information provided by at least one of said sensors, that the mold cavity has been completely or almost completely filled with molten plastic material, the vibration of the sonotrode is activated and/or the pressure of the plastic material applied in the melting chamber is increased by the relative movement of the sonotrode part with respect to the melting chamber.

The electronic control unit detects whether the mold cavity is full or almost full, since it knows the volume of the mold cavity and the metering of the plastic material, which allows it to know whether the plastic material injected into the mold cavity from the melting chamber is sufficient to fill it completely or almost completely (more than 80%). Activating the vibration of the sonotrode and/or increasing the pressure at this time results in greater compaction of the molten plastic material disposed in the mold cavity, which prevents voids or deterioration in the molded plastic part during solidification.

According to another envisaged embodiment of the method, the electronic control unit determines between the first production cycle and the second production cycle if the temperature of the sonotrode portion obtained from the operating sensor exceeds a predetermined temperature range, in which case a cooling cycle is performed.

According to one embodiment, the cooling cycle comprises:

· Make the ultrasonic generator part in thermal contact with the cooling device;

Activate the cooling device.

The cooling device includes, for example, a cold air generator (such as a vortex device) connected to a coolant fluid distribution element annularly arranged around the melting chamber inlet, which allows coolant fluid to be supplied to the tip of the sonotrode part from multiple directions simultaneously.

Further features of the present invention will become apparent from the following detailed description of the embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages and features will be better understood based on the following detailed description of embodiments with reference to the accompanying drawings, which are to be construed as illustrative and non-limiting, in which:

FIG1 schematically shows an apparatus for injecting molten plastic material into a mold cavity in an initial step, wherein solid plastic material has already been metered into a melting chamber, located adjacent to and in communication with the mold cavity, and an ultrasonic generator having a portion facing the melting chamber, and adjacent to its inlet, a sensor connected to an electronic control unit is indicated by a dotted line;

Fig. 2 is a view corresponding to Fig. 1 , with the sonotrode partially moved until it contacts the plastic material;

FIG3 shows the subsequent step of melting the plastic material by activating the sonotrode;

FIG4 shows the introduction of molten plastic material into the mold cavity by moving an ultrasonic generator into the melting chamber;

FIG5 shows the ultrasonic generator positioned outside the melting chamber and subjected to the action of the blown coolant fluid; and

FIG. 6 shows an embodiment of a coolant fluid distribution element of a sonotrode.

DETAILED DESCRIPTION

According to a non-limiting embodiment shown in the accompanying drawings, a device for injecting molten plastic material into a mold cavity 30 comprises a hollow melting chamber 20, which in the example is cylindrical, said melting chamber 20 being open at its upper end and closed at its lower end, except for an orifice opening 22 provided at said lower end, which connects said melting chamber 20 with the mold cavity 30.

In this example, the melting chamber 20 also has a channel 21 in its upper part for loading solid plastic material, connecting the side wall of the melting chamber 20 with a metered solid plastic material feeder. An automatic metering device controlled by an electronic control device 50 and equipped with a feed sensor 41 allows the metered feeding to be performed in a precise manner.

The ultrasonic generator 10 is arranged above the melting chamber 20 and is provided with a protruding portion 11 having a size and shape complementary to the melting chamber 20, allowing the portion 11 to be introduced into the melting chamber 20 up to its lower end, thereby coming into contact with any amount of solid plastic material arranged in the melting chamber 20 and thus melting and driving any amount of molten plastic material from the melting chamber 20 to the mold cavity 30 through the orifice opening 22.

The mould cavity 30 can be opened (see Figure 5) to allow extraction of the moulded plastic part after curing, ready for a new production cycle.

In the preferred embodiment shown in the drawings, the sonotrode 10 is mounted on a linear guide system to allow its guided vertical movement, a portion 11 of the sonotrode 10 is aligned with the melting chamber 20, and an electrically actuated translation device 12 allows for controlled vertical movement of the sonotrode. The translation device 12 shown in the embodiment is an electric motor.

As shown in FIG1 , the motor shown has a resistance sensor 40 which allows, for example, based on the control of the power consumption of the motor connected to an electronic control device 50 , to detect the resistance of the plastic material deposited in the melting chamber 20 against the relative movement of the portion 11 of the sonotrode 10 inside said melting chamber 20 , thereby deducing when the tip of the sonotrode 10 comes into contact with said plastic material and the reaction caused by the fluidity of the molten plastic material.

The electronic control device 50 also optionally has environmental sensors 42 arranged to measure environmental parameters, such as ambient temperature and humidity, and operating sensors 43 arranged to measure different parameters of the device, such as the temperature of its components or plastic materials, or the relative positions of elements.

All these parameters influence the melting of the plastic material and the molding process, so it is important that the electronic control unit 50 obtains all necessary information from said sensors 40 , 41 , 42 , 43 .

The electronic control device 50 can also act on the various actuators of the proposed device, such as the ultrasonic generator 110 , the translation device 12 , the cooling device 60 , or the metering device for metering the solid plastic material into the melting chamber 20 .

The electronic control device 50 performs the regulation of the actuation parameters of all these actuators on the basis of the information provided by the different sensors 40 , 41 , 42 , 43 .

The electronic control unit 50 may also adjust the operating parameters based on other information, such as information contained in a memory of the electronic control unit 50 or data related to the type or form of solid plastic material used, and the data may be stored in the memory and/or input by an operator via an interface.

The memory preferably stores operating ranges indicating the maximum and minimum values that each parameter can adjust; these ranges can be interdependent and variable based on some variable parameter (e.g., ambient temperature, type of plastic material, configuration of mold cavity 30 or exit orifice 22, etc.). The ranges can also be interdependent and variable based on the duration of the production cycle.

Furthermore, the electronic control unit 50 receives information regarding the minimum energy required to melt the solid plastic material (depending on its type and form), as well as the maximum energy required without causing degradation of the plastic material (also depending on its type and form), and is able to know the energy applied to the plastic material by actuating the various actuators regulated by the electronic control unit 50. This allows the operating parameters to be regulated to ensure that the energy applied to the plastic material does not exceed the maximum limit at any point in the production cycle, thereby preventing degradation of the plastic material.

FIG1 schematically illustrates the initial steps of a production cycle, wherein the electronic control unit 50 provides solid plastic material in a metered manner to a melting chamber by regulating an automatic feeder.

The feed sensor 41 provides the electronic control unit 50 with information on the weight and quantity of the pellets introduced into the melting chamber 20 .

FIG2 shows the next step in the production cycle, in which the translation device 12 can be activated by the electronic control unit 50, so that the part 11 of the sonotrode 10 is introduced into the melting chamber 20. When the tip of the part 11 of the sonotrode 10 comes into contact with the plastic material, the resistance sensor 40 (the resistance to the forward movement of the sonotrode) detects the resistance and transmits this information to the electronic control unit 50. From this information, the volume of the melting chamber 20 occupied by the solid plastic material is known, together with the information received from the feed sensor 41 and, optionally, information input by the operator with reference to the type and form of the solid plastic material supplied; the electronic control unit 50 can infer whether the plastic material is more or less compacted when deposited in the melting chamber, allowing the operating parameters to be adjusted according to this information.

FIG3 shows a subsequent step in the production cycle, in which the vibration of the sonotrode is activated together with an additional movement of the sonotrode, so that the plastic material in the melting chamber 20 is melted and compacted. At this stage, the resistance sensor 40 can determine the fluidity obtained by the plastic material, but this information can also be derived from the average temperature of the molten plastic material provided by the operating sensor 43.

Based on this information, the electronic control unit 50 can make additional adjustments to the speed and acceleration of the movement of the vibration and sonotrode 10 in order to achieve and/or maintain desired flow conditions for the molten plastic material and for optimal introduction of the molten plastic material into the mold cavity 30 .

4 shows the final step of the production cycle, wherein the mold cavity 30 has been completely filled or nearly filled. At this point, the electronic control unit 50 modifies the vibration conditions and/or increases the pressure, speed or acceleration of the ultrasonic generator 10 in order to compress the molten plastic material in the mold cavity 30.

After this step is complete, the molded plastic material is cooled, allowed to harden, and then removed from the mold; once again, the mold cavity 30 is ready to start production again.

After the production cycle is finished, the electronic control unit 50 determines whether the temperature of the portion 11 of the sonotrode 10 is below predetermined parameters based on the data provided by the operating sensor 43. If it is below said predetermined parameters, a new production cycle can be started, but if not, a cooling cycle is required.

FIG5 shows the cooling cycle, showing how the portion 11 of the sonotrode 10 is extracted from the melting chamber 20 , facing the cooling device 60 , which in this embodiment (see details in FIG6 ) consists of a diffuser for driving the coolant gas on the portion 11 of the sonotrode 10 from the area located around it.

Claims (15)

1. An apparatus for injecting molten plastic material into a mold cavity (30), the apparatus comprising a melting chamber (20) connected to: • The easily vibrating part (11) of the ultrasonic generator (10) of the ultrasonic transducer; • A channel (21) for loading solid plastic material; and • At least one outlet hole (22) for supplying molten plastic material to the melting chamber of the mold cavity (30); The device includes a translation device (12) for providing relative movement between the portion (11) of the ultrasonic generator (10) and the melting chamber (20), adjusting the position of the top of the portion (11) of the ultrasonic generator (10) within the melting chamber (20); The device is characterized by further comprising: - A resistance sensor (40) configured for detecting motion resistance, wherein the plastic material loaded in the melting chamber (20) is metered through the channel (21) to resist relative motion between the portion (11) of the ultrasonic generator (10) and the melting chamber (20); and - A programmable electronic control device (50) for adjusting the translation device (12) based at least on information provided by the resistance sensor (40). 2. The apparatus according to claim 1, characterized in that it further comprises: A feed sensor (41) is configured to detect and measure the total amount of solid plastic material and/or the weight of solid plastic material injected into the melting chamber (20); and/or An environmental sensor (42) configured to detect ambient temperature and/or humidity; and/or Operate the sensor (43), which is configured to detect one or more of the following parameters: • The relative position of part (11) of the ultrasonic generator (10) with respect to the melting chamber (20); • The temperature of the ultrasonic generator (10); • The temperature of part (11) of the ultrasonic generator (10); • The temperature of the melting chamber (20); • The temperature of the mold cavity (30); • The temperature of the plastic material. 3. The apparatus according to claim 2, characterized in that the electronic control device (50) controls the actuator, which allows adjustment of one or more of the following operating parameters of the apparatus based at least on data provided by at least one of the sensors at least the resistance sensor (40), the feed sensor (41), the environmental sensor (42), or the operation sensor (43): • Actuation of the ultrasonic generator (10); • The relative position of a portion (11) of the ultrasonic generator (10) relative to the melting chamber (20) when the ultrasonic generator (10) is activated to vibrate; • The actuation time of the ultrasonic generator (10); • The vibration frequency of the ultrasonic generator (10); • The vibration amplitude of the ultrasonic generator (10); • The relative motion speed of part (11) of the ultrasonic generator (10) relative to the melting chamber (20); • The acceleration of the relative motion of a portion (11) of the ultrasonic generator (10) with respect to the melting chamber (20); • Pressure is applied to the plastic material contained in the melting chamber (20) by the relative motion of a portion (11) of the ultrasonic generator (10) relative to the melting chamber (20); • Actuation of the cooling device (60). 4. The apparatus according to claim 3, characterized in that... The electronic control device (50) has a user interface that allows the operator to input information about the type of plastic material and/or the form of the plastic material to be used; and The electronic control device (50) also adjusts the device's variables and operating parameters based on information input by the operator. 5. The apparatus according to claim 4, characterized in that... The electronic control device (50) has a memory storing variables and operating parameters associated with one or more of the following elements: the type of plastic material, different available forms of the solid plastic material, the structure of the outlet orifice (22) providing an inlet within the mold cavity (30), or the structure of the mold cavity (30), and The electronic control device (50) also links and adjusts the device's variables and operating parameters based on information contained in the memory. 6. The apparatus according to any one of claims 1-2, characterized in that the translation device (12) is electrically actuated, and the resistance sensor (40) detects the power consumption of the translation device (12) during its actuation. 7. The apparatus according to any one of claims 1-2, characterized in that a cooling device (60) is integrated for cooling a portion (11) of the ultrasonic generator (10), comprising a coolant gas diffuser disposed around the inlet of the portion (11) of the ultrasonic generator (10) in the melting chamber (20), configured to diffuse the coolant gas through the portion (11) of the ultrasonic generator (10) extracted from the melting chamber (20). 8. The apparatus according to any one of claims 1 to 2, characterized in that a cooling device (60) is integrated for cooling a portion (11) of the ultrasonic generator (10), comprising a coolant fluid circuit disposed around at least one portion of the melting chamber (20), configured to allow coolant fluid to flow therein to cool at least one portion of the melting chamber (20) in thermal contact with the portion (11) of the ultrasonic generator (10). 9. A method for injecting molten plastic material into a mold cavity (30) using the apparatus according to any one of claims 4-5, the method comprising the steps of forming a production cycle: a) Metered plastic material is loaded into the melting chamber (20) through the channel (21) for injecting solid plastic material; b) Activate the ultrasonic generator (10) to melt the plastic material; c) Actuating the translation device (12) provides the relative position between the portion (11) of the ultrasonic generator (10) and the melting chamber (20), further inserting the tip of the portion (11) of the ultrasonic generator (10) into the melting chamber (20) and pushing the molten plastic material into the mold cavity (30) through the outlet hole (22); Its features Before performing step b), a relative position is first established between the portion (11) of the ultrasonic generator (10) and the melting chamber (20). The tip of the portion (11) of the ultrasonic generator (10) is inserted into the melting chamber (20) until the resistance sensor (40) detects that the plastic material already inserted into the melting chamber (20) resists forward movement of the portion (11) of the ultrasonic generator (10), thereby detecting contact between the portion (11) of the ultrasonic generator (10) and the plastic material, and providing an indication relative to the volume of the melting chamber (20) occupied by the plastic material; The electronic control device (50) adjusts the actuation of the ultrasonic generator (10) and the translation device (12) in step c) based at least on the data provided by the resistance sensor (40). 10. The method according to claim 9, characterized in that the electronic control device (50) further adjusts the operating parameters based on information provided by the following device: A feed sensor (41) is configured to detect the unit quantity of the solid plastic material and/or the weight of the solid plastic material injected into the melting chamber (20); and/or An environmental sensor (42) configured to detect ambient temperature and/or humidity; and/or Operate the sensor (43), which is configured to detect one or more of the following parameters: • The relative position of part (11) of the ultrasonic generator (10) with respect to the melting chamber (20); • The temperature of the ultrasonic generator (10); • The temperature of part (11) of the ultrasonic generator (10); • The temperature of the melting chamber (20); • The temperature of the mold cavity (30); • The temperature of the plastic material. 11. The method according to claim 9, characterized in that the electronic control device (50) adjusts one or more of the following operating parameters based at least on data provided by the resistance sensor (40): • The relative position of a portion (11) of the ultrasonic generator (10) relative to the melting chamber (20) when the ultrasonic generator (10) is activated to vibrate; • The actuation time of the ultrasonic generator (10); • The vibration frequency of the ultrasonic generator (10); • The vibration amplitude of the ultrasonic generator (10); • The relative motion speed of part (11) of the ultrasonic generator (10) relative to the melting chamber (20); • The acceleration of the relative motion of a portion (11) of the ultrasonic generator (10) with respect to the melting chamber (20); • Pressure is applied to the plastic material contained in the melting chamber (20) by the relative motion of a portion (11) of the ultrasonic generator (10) relative to the melting chamber (20); Based on information acquired by the different sensors (40, 41, 42, 43) and based on appropriate minimum and maximum energy ranges stored in the electronic control device (50), the electronic control device (50) calculates the energy that must be applied to the plastic material through the operating parameters, and calculates the adjustment of the operating parameters such that the applied energy is sufficient to cause the plastic material to melt properly but not sufficient to cause the plastic material to degrade. 12. The method according to claim 11, characterized in that the at least one different sensor (40, 41, 42, 43) measures and provides information at different times in the production cycle, and the electronic control device (50) performs different adjustments of the operating parameters at different times in the production cycle, adjusting them at least based on the information provided by the at least one sensor (40, 41, 42, 43). 13. The method according to claim 12, characterized in that when the electronic control device (50) determines that the plastic material has reached a predetermined flowability by information provided by at least one of the sensors (40, 41, 42, 43), it is able to apply the vibration parameters or vibration amplitude parameters of the ultrasonic generator according to predetermined data in the electronic control device, depending on a specific configuration file. 14. The method according to claim 11, characterized in that when the electronic control device (50) determines by information provided by at least one of the sensors (40, 41, 42, 43) that the molten plastic material has completely or almost completely filled the mold cavity (30), the vibration of the ultrasonic generator (10) is activated, and/or the pressure of the plastic material applied in the melting chamber (20) increases due to the velocity or acceleration of the relative movement of a portion (11) of the ultrasonic generator (10) relative to the melting chamber (20). 15. The method according to claim 10, characterized in that, between the first production cycle and the second production cycle, the electronic control device (50) determines whether the temperature of a portion (11) of the ultrasonic generator (10) obtained from the operation sensor (43) exceeds a predetermined temperature range, and performs a cooling cycle in the case of such exceeding the predetermined temperature range, comprising: • Make part (11) of the ultrasonic generator (10) come into thermal contact with the cooling device (60); • Activate the cooling device (60).