AT521585B1 - Injection unit for a molding machine - Google Patents

Abstract

Injection unit for a molding machine comprising at least one injection cylinder (2), a non-return valve (3) being provided in the at least one injection cylinder (2) in order to prevent a plasticized compound from flowing back into the at least one injection cylinder (2), with at least one ultrasonic device ( 4) is provided with at least one transmitting unit (4a) for transmitting and at least one receiving unit (4b) for receiving ultrasound, which at least one ultrasonic device (4) is or can be connected to an evaluation unit (5), the at least one transmitting unit (4a ) arranged on the at least one injection cylinder (2) and / or connected to the at least one injection cylinder (2) via a sound-conducting connection and / or integrated into the at least one injection cylinder (2) and the at least one receiving unit (4b) on the at least an injection cylinder (2) arranged and / or a sound guide de connection is connected to the at least one injection cylinder (2) and / or integrated into the at least one injection cylinder (2) and the evaluation unit (5) is designed to detect the presence and / or presence of the at least one ultrasonic device (4) on the basis of a measurement to determine a geometry and / or a position of the non-return valve (3) in the at least one injection cylinder (2) and to output a message based on the measurement.

Description

description

The present invention relates to an injection unit for a molding machine with the features of the preamble of claim 1, a molding machine with such an injection unit and a method for checking at least one injection unit.

In this context, molding machines can be understood to mean injection molding machines, transfer presses, presses and the like.

In the prior art common injection units for molding machines comprise at least one injection cylinder, wherein a non-return valve is provided in the at least one injection cylinder to prevent a backflow of a plasticized mass in the at least one injection cylinder. In most cases, a plasticized mass that is located in the injection cylinder is pushed out of the injection cylinder by an injection device. This usually takes place via an injection side of the injection cylinder, which is often designed as an injection nozzle. In order to prevent the plasticized molding compound from flowing back into the interior of the injection cylinder through the injection nozzle or an injection opening of the injection cylinder, a non-return valve is provided.

Since the non-return valve in the injection cylinder is a moving component and is continuously connected to the plasticized material flowing past, the non-return valve is subjected to friction, which inevitably leads to wear. It is known from the prior art that non-return valves represent a wear part of the injection unit and must be replaced at a specified service interval, since they can no longer guarantee the required process accuracy due to wear after a given time.

Even if process parameters can be set during the continuous wear of the non-return valve in order to counteract the growing inaccuracy caused by wear, there is a limit at which this is no longer possible and the non-return valve must be replaced.

Changing the process parameters also turns out to be difficult, since only an increasing inaccuracy of the process accuracy can indicate wear of the non-return valve and the process parameters can be adjusted subsequently.

[0007] Consequently, the prior art strives to be able to determine an exact present state of the non-return valve in order to be able to take it into account with the process parameters or a service interval.

The facts presented here, however, all take place inside the injection cylinder, which for obvious reasons is not accessible during operation.

It is known from the prior art to use ultrasonic measuring devices to determine the wear in a plasticizing unit, as disclosed, for example, by AT 510024 A4 or US 4604251 A. It is also known from DE 10 2017 117 003 A1 or AT 12211 U1 to integrate measuring devices into the plasticizing unit by means of complex and cost-intensive designs in order to determine different axial positions of a non-return valve especially long-term monitoring is not possible.

The object of the invention is therefore to provide an injection unit and a method with which the non-return valve is accessible during operation and with the least possible impairment of the manufacturing process.

With regard to the injection unit for a molding machine, this object is achieved by the features of claim 1. This is done by providing at least one ultrasonic device with at least one transmitting unit for transmitting and at least one receiving unit for receiving ultrasound, which at least one ultrasonic device with

an evaluation unit, wherein - the at least one transmitting unit is arranged on the at least one injection cylinder and / or connected to the at least one injection cylinder via a sound-conducting connection and / or is integrated in the at least one injection cylinder and - the at least one receiving unit is on the At least one injection cylinder is arranged and / or connected to the at least one injection cylinder via a sound-conducting connection and / or is integrated into the at least one injection cylinder and the evaluation unit is designed to determine its presence and / or geometry on the basis of a measurement of the at least one ultrasonic device and / or to determine a position of the non-return valve in the at least one injection cylinder and to output a message based on the measurement, the evaluation unit being designed to determine a distance between an inner surface of the at least one injection cylinder To determine tzzylinders and the locking ring arranged therein and to determine wear by the specific distance between the inner surface of the at least one injection cylinder and the non-return valve arranged therein.

With regard to the method, the set object is achieved by the features of claim 23, in that a presence and / or a position and / or a geometry of the non-return valve in the at least one injection cylinder is determined by means of ultrasound.

It should be noted that the at least one ultrasonic device can be designed as an integral transmitter or receiver. Alternatively, the at least one ultrasonic device can be constructed in several parts, d. This means that it has at least one transmitting unit and - separately therefrom - at least one receiving unit.

Preferably, however, it can be provided that the at least one transmitting unit and the at least one receiving unit are formed by the same components for fulfilling a transmitting function and a receiving function.

For example, when using a piezo element (e.g. a piezo loudspeaker) it can be provided that, by reversing the piezo effect, the piezo element is excited to oscillate, which leads to an ultrasound emission. Furthermore, by reversing the function, such a piezo element can subsequently also be used as a receiving unit.

By arranging at least one transmission unit on the at least one injection cylinder and / or in the at least one injection cylinder and / or in that the at least one transmission unit is connected to the at least one injection cylinder via a sound-conducting connection and a receiving unit is connected to the at least one Injection cylinder and / or in the at least one injection cylinder and / or in that the at least one receiving unit is connected to the at least one injection cylinder via a sound-conducting connection, information about this can be obtained in a very precise manner by sending and receiving the at least one ultrasonic device be given whether there is a non-return valve at all in the at least one injection cylinder or which geometry or position the non-return valve has / assumes in the at least one plasticizing cylinder.

The sound-conducting connection can be implemented, for example, via a metallic contact or a - preferably temperature-resistant - gel. The gel can improve the coupling of ultrasonic signals transmitted for the purpose of measurement.

For the purpose of the measurement, ultrasonic signals transmitted by the ultrasonic device can be transmitted in a modulated manner in order to facilitate the recognition of the signal during the measurement by detecting the modulation.

Measurement signals which are measured by the ultrasonic device, in particular by the receiving unit, and fed to the evaluation unit can be subjected to preprocessing in the communications sense before being transmitted to the evaluation unit. Such processing can, for example, be an analog-to-digital conversion of the signals and / o-

which involve applying different filters.

Advantageous embodiments of the invention are defined in the dependent claims.

It can be provided that the evaluation unit is designed to determine at least part of the geometry and / or wear and / or a thickness, preferably a wall thickness, of the at least one injection cylinder based on a measurement of the at least one ultrasonic unit.

It is preferably provided that the non-return valve is designed as an annular non-return valve, wherein a locking ring is axially movable between a stop position on a web of the tip and a stop position on a pressure ring.

When measuring the presence and / or a geometry and / or the position according to the invention, in particular the presence and / or the geometry and / or the position of the locking ring can be detected.

With a ring non-return valve there are different types of wear. For example, what is known as pressure wear forms between the locking ring and a ridge at the tip. During dosing, the locking ring is in a front stop position due to the high dosing pressure and the low pressure on the tool side - in which the locking ring is in contact with a web of the tip. Due to the different friction conditions (locking ring seals on the circumference and therefore has a higher friction than the tip), the speed of the tip and locking ring is different. Due to the relative speed, paired with the pressure situation, the locking ring works its way into the web of the tip. As a result, the stroke of the tip when closing becomes higher and less defined.

This influences the process accuracy during injection in the highest possible way and often has to be corrected externally by adjusting the switchover point.

Furthermore, there is axial wear of the locking ring of an annular non-return valve. Due to the axial movement of the locking ring and the incorporation of the locking ring into the web of the tip, the locking ring is shortened in the axial direction due to wear. Normally, however, this wear is significantly less compared to the wear on the web of the tip. By reducing the axial length of the locking ring, the stroke of the locking ring when closing is significantly higher, which significantly reduces the process accuracy. This has a very high impact on the process accuracy during injection and often has to be corrected externally by adjusting the switchover point.

Furthermore, a ring non-return valve exhibits radial wear on the locking ring. The rotation of the plasticized mass to be injected causes the locking ring (when dispensing in the front position) to rotate due to the pressure between the locking ring and the tip. The locking ring thus rotates in the injection cylinder, which leads to high friction in the gap between the locking ring and the injection cylinder.

This friction leads to wear especially when the lock runs “dry” and there is no plasticized mass in the gap between the locking ring and plasticizing cylinder and there is direct contact between the injection cylinder and the non-return valve. Radial wear has a direct impact on the tightness of the barrier. With a larger gap, the tightness is increasingly reduced. Under injection pressure, the locking ring moves backwards and seals between the locking ring and a pressure ring. For the tightness of the non-return valve, a “clean” contact between the locking ring and the pressure ring is required. The high injection pressures lead to high contact forces between the locking ring and the pressure ring, which in turn can lead to wear. Wear in the sealing area leads to poor sealing of the non-return valve under injection pressure.

It can preferably be provided that the ultrasonic device is designed to carry out a transit time measurement. This is a simple way of measuring the non-return valve. Of course, interferometric measurements or measurements on

due to diffraction effects.

In the context of the invention, a measurement can be understood to mean that the transmitter unit emits an ultrasonic signal at least once, whose reflected, diffracted or otherwise changed signal by the interaction with the non-return valve is detected by the receiver unit. With pulsed transmission of the signals, which can be advantageous in connection with transit time measurements, the ultrasonic pulses transmitted by the transmission unit can be transmitted very often in a short time. This means that several thousand measurements (and more) can be carried out per second.

The continuous transmission of the ultrasonic signals by the transmitter unit is also conceivable, e.g. in connection with interferometric measurements.

Furthermore, it can be provided that the evaluation unit is integrated into the at least one ultrasonic device. However, embodiments are also conceivable in which the evaluation unit is designed as a separate component and the at least one ultrasonic device is or can be connected to the evaluation unit.

For example, it can be provided that the function of the evaluation unit is carried out by a central control or regulating unit of a molding machine. However, it is also possible that the at least one ultrasound device can be connected to an evaluation unit via a LAN, WLAN and / or remote data transmission connection (e.g. Internet).

It is preferably provided that at least two ultrasonic devices are provided, with at least two transmitting units and at least two receiving units being arranged along a circumference of the at least one injection cylinder on the at least one injection cylinder and / or connected to the at least one injection cylinder via a metallic contact / or are integrated into the at least one injection cylinder, preferably within a radial cross section of the at least one injection cylinder. For example, if at least two ultrasonic devices are provided along a circumference of the at least one injection cylinder within a radial cross section through the at least one injection cylinder, it is possible to determine an exact position of the non-return valve in the at least one injection cylinder. An interaction between the at least two ultrasound devices is also entirely conceivable, so that ultrasound signals emitted by one ultrasound device (or reflections of these ultrasound signals) are received by the other ultrasound device.

It can preferably be provided that the evaluation unit is designed to determine a position of the locking ring in relation to a further component of the non-return valve. Alternatively or additionally, it can be provided that the evaluation unit is designed to determine an end of the locking ring facing away from an injection opening of the plasticizing cylinder.

It is provided that the evaluation unit is designed to determine a distance between an inner surface of the at least one injection cylinder and the non-return valve arranged therein. More precisely, a distance between a locking ring, a non-return valve and an inner surface of the at least one injection cylinder is determined. It is provided that the evaluation unit is designed to determine wear through the specific distance between the inner surface of the at least one injection cylinder and the non-return valve arranged therein. For example, if the distance increases, it can be concluded that there has been wear on the non-return valve and / or the at least one injection cylinder. Furthermore, it can be provided that the evaluation unit is designed to determine the wear on the non-return valve and / or the inner surface of the at least one injection cylinder. Thus, for example, radial wear of the non-return valve can be determined and a possible decrease in the tightness of the non-return valve can be deduced.

It can particularly preferably be provided that the evaluation unit is designed to have at least one recess on the non-return valve and / or on a component of the

To determine the non-return valve. For example, a recess can be recognized on a locking ring that occurs as a result of wear or that was applied in advance during the manufacture of the locking ring. By recognizing this depression and observing this depression for a longer period, it is possible, for example, to determine a movement of the locking ring (particularly preferably a rotation).

It can particularly preferably be provided that the evaluation unit is designed to determine a position and / or movement of the non-return valve from separate measurements of the at least one ultrasonic device and / or to determine a component of the non-return valve - preferably a locking ring. It can preferably be provided that at least two separate measurements

- be carried out by the same ultrasonic device at different times

and / or - are carried out by at least two ultrasonic devices.

Spatially separate measurements can be carried out both by moving the ultrasonic unit and by pivoting the ultrasonic unit.

The evaluation unit can be designed to determine at least part of the non-return valve geometry of the non-return valve from separate measurements. It can thus be provided, for example, that the evaluation unit can recognize a shape or a type of the non-return valve from separate measurements.

Preferably, it can be provided that the evaluation unit is designed to use separate measurements on the one hand and / or a process parameter provided and / or a machine parameter provided on the other hand, a geometric dimension of the non-return valve and / or a component of the non-return valve, particularly preferably a length of a Locking ring to determine. For example, it can be provided that the evaluation unit receives information via the machine parameters provided that the non-return valve should be in a certain position at a certain time during the injection cycle. The evaluation unit can then use a measurement to determine whether the non-return valve is actually in this position. If a non-return valve is not detected in this position, it can either be concluded that there is no non-return valve, that it is in the wrong position, or that the non-return valve is so worn due to wear that the ultrasonic device cannot detect the presence of a non-return valve.

It can particularly preferably be provided that the evaluation unit is designed to output an alarm and / or to change a control signal for the injection unit.

It can be provided that the evaluation unit is designed to output a message if an actual variable determined by the evaluation unit exceeds or falls below a predeterminable limit value. The actual value is to refer to one of the already mentioned variables, such as a distance between an inner surface of the at least one injection cylinder and the non-return valve arranged therein, wear, a recess (for example in the form of a linear groove) on the non-return valve, a layer and / or a movement of the non-return valve, a rotational movement of the non-return valve, a geometric dimension of the non-return valve and / or a component of the non-return valve and / or the like.

It can be provided that the evaluation unit is connected or connectable to a display device for displaying a position of the non-return valve and / or a state of the non-return valve and / or a state of the at least one injection unit and / or a position of a deposit. For example, it can be provided that a display (as a display device) is provided, which visually shows the current status of the non-return valve.

Furthermore, it can be provided that the evaluation unit is equipped with a display device for displaying wear on the non-return valve and / or the at least one plasticizer.

ornamental cylinder, connected or connectable.

In a further embodiment it can be provided that the evaluation unit is designed to detect a presence and / or a geometry and / or a position of the non-return valve during operation of the injection unit - preferably during an injection movement and / or a metering movement to determine the at least one injection cylinder and to output a message based on the measurement.

Protection is also sought for a molding machine with an injection unit according to the invention, an evaluation unit preferably being designed to determine the presence and / or geometry and / or position of the non-return valve during operation of the molding machine.

It can be provided that the at least one evaluation unit is designed to output a message to an operator (for example visually or acoustically) or to a central control or regulation unit of the molding machine connected to the evaluation unit. It can also be provided that the at least one evaluation unit is connected to a central control or regulation unit of the molding machine, it being possible for the tasks of the at least one evaluation unit to be partially taken over by the central control or regulation unit of the molding machine.

Further advantages and details of the invention emerge from the figures and the associated description of the figures. Show:

1 shows an injection unit with a non-return valve,

2a shows an injection unit according to the invention for a molding machine, FIG. 20 shows a diagram which shows the results of the measurement from FIG. 2a, FIG. 3a shows a second position of the exemplary embodiment from FIG. 2a,

FIG. 3b is a diagram showing the results of the measurement from FIG. 3a,

1 shows an injection unit 1 with a non-return valve 3 (designed as an annular non-return valve) which is arranged in an injection cylinder 2.

In this exemplary embodiment, the non-return valve 3 is arranged between the plasticizing screw 10 and the outlet opening of the injection cylinder 2.

In this embodiment, the non-return valve 3 is arranged centrally on a front end of a plasticizing screw 10.

The non-return valve 3 has a locking ring 6, which has a length | having. This locking ring 6 is movably arranged between a pressure ring 9 and a web 7 of the tip 8 of the non-return valve 3. During the dosing of the injection unit 1, the locking ring 6 is pressed against the web 7 of the tip 8 by the pressure of a plasticized mass, which is conveyed by the plasticizing screw 10, and the plasticized mass can pass over the area 12 through the web 7 of the tip 8 the outlet opening of the injection cylinder 2 leave the injection unit 1. As soon as the pressure in the area of the tip 8 of the non-return valve 3 becomes higher than in the interior of the injection cylinder 2 (in the area of the plasticizing screw 10) - namely during injection - the locking ring 6 is pushed back until it rests against the pressure ring 9 of the non-return valve 3 and thus seals. This prevents the plasticized mass from flowing back and the plasticizing screw 10 can be used as a piston for injecting the plasticized mass into a mold.

Since the plasticized material is set in a twisting motion by the plasticizing screw 10 and the locking ring 6 is not secured against a rotational movement, it is additionally set in motion and rotated during use by the twisting of the plasticized mass.

In injection molding, “metering up” is understood to mean the process during which new plastic is plasticized and collected (metered) in the antechamber.

During ongoing operation of the injection unit 1, different types of wear on the non-return valve 3 are to be expected.

So-called “pressure wear” is to be expected between the locking ring 6 and the web 7 of the tip 8. The locking ring 6 works its way into the web 7. During the dosing, the locking ring 6 is in the front position. Due to the different friction conditions (locking ring 6 seals on the circumference and therefore has a higher friction than web 7), the speed of web 7 and locking ring 6 is different. As a result of this relative speed - paired with the pressure situation - the locking ring 6 works its way into the web 7. In other words, the locking ring 6 rubs into the web 7 due to the high pressure and the relative movement. As a result, the stroke of the tip 8 when the non-return valve is closed becomes higher and less defined. This has a very high impact on the process accuracy during injection and often has to be corrected externally by adjusting the switchover point.

Another wear that occurs on the non-return valve 3 is the axial wear of the locking ring 6. The axial movement of the locking ring 6 and the incorporation of the locking ring 6 into the web 7 of the tip 8 shortens the locking ring 6 in the axial direction due to wear. In the normal case, however, this wear is significantly less compared to the wear on the web 7 of the tip 8. By reducing the axial length | of the locking ring 6, the stroke of the locking ring 6 is significantly higher when closing, which significantly reduces the process accuracy. This influences the process accuracy and often has to be corrected externally by adjusting the switchover point.

Radial wear of the locking ring 6 also occurs. As a result of the rotation of the plasticizing screw 10, the locking ring 6 is also rotated (in the front position when metering up) due to the pressure between the locking ring 6 and the web 7. The locking ring 6 thus rotates in the injection cylinder 2, which leads to high friction in the gap between the locking ring 6 and the injection cylinder 2. This friction leads to wear. Especially when the non-return valve 3 is running “dry” and there is no plasticized compound in the gap d and there is direct contact between the injection cylinder 2 and the non-return valve 3. Radial wear of the non-return valve 3 has direct consequences on the tightness of the non-return valve 3. With an increasing gap d, the tightness is increasingly reduced.

Under injection pressure, the locking ring 6 moves backwards and seals between the locking ring 6 and the pressure ring 9. A “clean” contact, that is to say a contact with a good surface fit between the locking ring 6 and the pressure ring 9, is required for tightness. The high injection pressures lead to high contact forces between the locking ring 6 and the pressure ring 9, which in turn can lead to wear.

Wear in the sealing area 12 leads to poorer sealing of the non-return valve 3 during injection.

2a shows an injection unit 1 according to the invention for a molding machine. An ultrasonic device 4 was arranged on the circumference of the injection cylinder 2. The remaining components are the same as in FIG. 1 and reference should be made to FIG. 1 at this point.

In this exemplary embodiment, the transmitting unit 4a and the receiving unit 4b are implemented by the same component (shown here as an ultrasonic device 4).

The ultrasonic device 4 in Fig. 2a is designed to emit an ultrasonic signal 13 which is partially reflected at the interfaces of the injection cylinder 2 and components of the non-return valve 3: the ultrasonic signal 13.1 is created by reflecting the ultrasonic signal 13 on the inner surface of the injection cylinder 2, - the ultrasonic signal 13.2 is created by reflection of the ultrasonic signal 13 on the outer surface of the locking ring 6, - the ultrasonic signal 13.3 is created by reflecting the ultrasonic signal 13 on the inner surface of the locking ring 6 and

The ultrasonic signal 13.4 is produced by reflection of the ultrasonic signal 13 on the base body of the non-return valve 3.

A transmitted ultrasonic signal 13 is reflected and the various reflected signals can be received again by the ultrasonic device 4, which is designed as a transmitter and a receiver.

The ultrasonic device 4 is also connected to the evaluation unit 5 via a signal-conducting connection 14 and can forward the received ultrasonic signals 13.1, 13.2, 13.3, 13.4 to the evaluation unit 5 via the signal-conducting connection.

Optionally, a separate data processing device can be provided between receiving unit 4b and evaluation unit 5, by means of which signals from ultrasound device 4 - in particular receiving unit 4b - can be processed for evaluation unit 5. Such processing can include an analog-to-digital conversion of the signals and the use of various filters, i.e. generally preprocessing in the communications sense.

The evaluation unit 5 is designed to, on the basis of time differences At, which occur between sending the ultrasonic signal 13 and receiving the ultrasonic signal 13.1 at the time t;, the ultrasonic signal 13.2 at the time t2, the ultrasonic signal 13.3 at the time ts and the ultrasonic signal 13.4 at the time tı to determine the distances that the ultrasonic signals have traveled. The evaluation unit 5 can thus determine a distance between the ultrasonic device 4 and the locking ring 6 on the outside from the time difference Ati (Ati = t2-to). With the aid of the time difference Atıı (Atı = tz - t1) and the time difference Atı, the evaluation unit 5 can determine a thickness of the locking ring 6 and thus a possible wear of the locking ring 6 in the radial direction can be deduced.

2b shows a diagram which shows the received ultrasonic signals 13.1, 13.2, 13.3, 13.4 of the ultrasonic device 4 along an abscissa shown as time t. The ordinate is to be understood as the intensity X of the received ultrasonic signals.

Because the non-return valve 3 is connected to the plasticizing screw 10, the plasticizing screw 10 being designed to perform an axial movement in the injection cylinder 2, the non-return valve 3 can be moved past the ultrasonic device 4 mounted on the injection cylinder 2, with the possibility arises, a length | of the locking ring 6 to measure and based on the measured length | of the locking ring 6 to infer an axial wear of the non-return valve 3.

For example, it is shown in FIG. 3a how the non-return valve 3 has been displaced in the axial direction. However, it can also be provided that the injection cylinder 2 with the ultrasonic unit 4 arranged thereon is displaced in the axial direction relative to the non-return valve or that only the ultrasonic unit 4 is displaced on the injection cylinder. The transmitting unit 4a and the receiving unit 4b are again implemented by the same component (shown here as an ultrasonic device 4). In the exemplary embodiment of FIG. 3 a, an ultrasonic signal 13 is again emitted by the ultrasonic device 4 at time to, which is reflected by the inner surface of the injection cylinder 2 and can be received again as an ultrasonic signal 13.1 at time t + by the ultrasonic device 4. A further reflection of the ultrasound signal 13 takes place on the base body of the non-return valve 3, as a result of which the ultrasound signal 13.4 can be received on the ultrasound device 4 at time t4. The ultrasonic signal 13.2 (reflection of the ultrasonic signal 13 on the outer surface of the locking ring 6) and the ultrasonic signal 13.3 (reflection of the ultrasonic signal 13 on the inner surface of the locking ring 6) are not present in this example. This means that there is no locking ring 6 in the measuring range (in contrast to the measurement shown in FIG. 2).

These ultrasonic signals can in turn be transmitted to the evaluation unit 5 via the signal-conducting connection 14, the evaluation unit 5 being designed to use the transmitted ultrasonic signals and a transmitted process parameter (for example

Course of the axial screw position), after which the evaluation unit 5 obtains information about the position in which the non-return valve 3 is and to what extent the non-return valve 3 is axially displaced, the length | of the locking ring 6 to be determined.

FIG. 3b again shows the received signals of the ultrasonic device 4 in a diagram.

The non-return valve 3 (ring non-return valve) shown in the figures is only to be understood as an example. The invention can also be used with other types of non-return valves, such as a slide-type non-return valve, a spring-loaded non-return valve, a non-return valve with a vane ring or a ball-type non-return valve.

REFERENCE CHARACTERISTICS LIST:

1 injection unit

2 injection cylinders

3 non-return valve

4 ultrasonic device 4a transmitter unit

4b receiving unit

5 Evaluation unit 6 Lock ring

7 bridge

8 tip

9 pressure ring

10 plasticizing screw

11 Pressure wear

12 area

13 Ultrasonic signal

13.1 Ultrasonic signal

13.2 Ultrasonic signal

13.3 Ultrasonic signal

13.4 Ultrasonic signal

14 signal-conducting connection

d distance

| length

t time

X intensity

to time 44 time t2 time t3 time ta time At time difference At time difference Atıu time difference

Claims (1)

Claims 1. Injection unit for a molding machine comprising at least one injection cylinder (2), wherein a non-return valve (3) is provided in the at least one injection cylinder (2) in order to prevent a plasticized compound from flowing back into the at least one injection cylinder (2), the The non-return valve (3) is designed as a ring non-return valve, a locking ring (6) being axially movable between a stop position on a web (7) of the tip (8) of the non-return valve (3) and a stop position on a pressure ring (9), wherein at least one ultrasonic device (4) with at least one transmitting unit (4a) for transmitting and at least one receiving unit (4b) for receiving ultrasound is provided, which at least one ultrasonic device (4) is or can be connected to an evaluation unit (5), wherein - The at least one transmission unit (4a) is arranged on the at least one injection cylinder (2) and / or is connected to the at least one injection cylinder (2) via a sound-conducting connection and / or is integrated into the at least one injection cylinder (2) and - The at least one receiving unit (4b) is arranged on the at least one injection cylinder (2) and / or is connected to the at least one injection cylinder (2) via a sound-conducting connection and / or is integrated into the at least one injection cylinder (2) and - The evaluation unit (5) is designed to determine the presence and / or a geometry and / or a position of the non-return valve (3) in the at least one injection cylinder (2) on the basis of a measurement by the at least one ultrasonic device (4) Output a message based on the measurement characterized in that the evaluation unit (5) is designed to determine a distance (d) between an inner surface of the at least one injection cylinder (2) and the locking ring (6) arranged therein and by the determined distance (d) between the inner one Surface of the at least one injection cylinder (2) and the locking ring (6) arranged therein to determine wear. 2. Injection unit according to claim 1, characterized in that the evaluation unit (5) is designed, based on a measurement of the at least one ultrasonic unit (4), at least part of the geometry and / or wear and / or a thickness, preferably a wall thickness to determine the at least one injection cylinder (2). 3. Injection unit according to at least one of the preceding claims, characterized in that the ultrasonic device (4) is designed to carry out a transit time measurement. 4. Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is integrated into the at least one ultrasonic device (4). 5. Injection unit according to at least one of the preceding claims, characterized in that at least two ultrasonic devices (4) are provided, with at least two transmitting units (4a) and at least two receiving units (4b) along a circumference of the at least one injection cylinder (2) on the at least an injection cylinder (2) arranged and / or connected via a sound-conducting connection to the at least one injection cylinder (2) and / or integrated into the at least one injection cylinder (2), preferably within a radial cross section of the at least one injection cylinder (2). 6. Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed to determine a position of the locking ring (6) in relation to a further component of the non-return valve (3). 7. Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed to determine an end of the locking ring (6) facing away from an injection opening of the plasticizing cylinder (2). 10/11 12th 13th 14th 15-16 17th 18th Austrian AT 521 585 B1 2021-07-15 Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed to determine the wear of the non-return valve (3) and / or the inner surface of the at least one injection cylinder (2). Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed to determine at least one depression on the non-return valve (3) and / or on a component of the non-return valve (3). Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed to determine a position and / or a movement of the non-return valve (3) and / or a component from separate measurements of the at least one ultrasonic device (4) the non-return valve (3), preferably a locking ring (6) - to be determined. Injection unit according to claim 10 and preferably claim 5, characterized in that at least two separate measurements - are carried out by the same ultrasonic device (4) at different times and / or - are carried out by at least two ultrasonic devices (4). Injection unit according to claim 10 or 11, characterized in that the evaluation unit (5) is designed to determine a rotational movement, preferably a component of the non-return valve (3), particularly preferably a locking ring (6), of the non-return valve (3) from separate measurements . Injection unit according to at least one of Claims 10 to 12, characterized in that the evaluation unit (5) is designed to determine at least part of a non-return valve geometry of the non-return valve (3) from separate measurements. Injection unit according to at least one of claims 10 to 13, characterized in that the evaluation unit (5) is designed to use separate measurements on the one hand and a provided process parameter and / or a provided machine parameter on the other hand to generate a geometric dimension of the non-return valve (3) and / or a Part of the non-return valve (3), particularly preferably a length (I) of a locking ring (6), to be determined. Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed to output a message if an actual variable determined by the evaluation unit (5) exceeds and / or falls below a predeterminable limit value. Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed to output the message in the form of an alarm and / or output the message in the form of a change in a control signal for the injection unit (1). Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) has a display device for displaying a position of the non-return valve (3) and / or a state of the non-return valve (3) and / or a state of the at least one injection cylinder ( 2) and / or a position of a deposit, connected or connectable. Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is or can be connected to a display device for displaying wear on the non-return valve (3) and / or the at least one plasticizing cylinder (2). 19. Injection unit according to at least one of the preceding claims, characterized in that the at least one transmitting unit (4a) and the at least one receiving unit (4b) are structurally combined in one unit, preferably the at least one transmitting unit (4a) and the at least one receiving unit ( 4b) are designed by the same components to fulfill a transmission function and a reception function. 20. Injection unit according to at least one of the preceding claims, characterized in that the evaluation unit (5) is designed during operation of the injection unit (1) - preferably during an injection movement and / or a metering movement - a presence and / or a geometry and / or to determine a position of the non-return valve (3) in the at least one injection cylinder (2) and to output a message based on the measurement. 21. Molding machine with at least one injection unit (1) according to at least one of the preceding claims. 22. Molding machine according to claim 21, characterized in that the evaluation unit (5) is designed to determine the presence and / or a geometry and / or a position of the non-return valve (3) during operation of the molding machine. 23. A method for checking at least one injection unit (1) of a molding machine according to at least one of claims 1 to 20, wherein by means of ultrasound a presence and / or a position and / or a geometry of the non-return valve (3) in the at least one injection cylinder (2) is determined, characterized in that a distance (d) between an inner surface of at least one injection cylinder (2) and a locking ring (6) of a non-return valve arranged therein is determined and by the determined distance (d) between the inner surface of the at least an injection cylinder (2) and the locking ring (6) arranged therein, wear is determined. In addition 3 sheets of drawings