Method for functional testing of several electrical machine components in an injection molding machine and injection molding machine

Abstract

A method for functional testing of several electrical machine components (H i ), which are connected to a common power supply line (9) in an injection molding machine (1), comprises, for each machine component (H i ) a verification step in which the machine component assigned to the respective verification step (H i ) is activated and all other machine components connected to the common supply line (9) (H i ) are deactivated, a current flow is detected in the common supply line (9) while the respective machine components (H i ) are activated, and a state of the respective machine components is derived from the detected current flow (H i ) is determined. Also described is an injection molding machine (1) with a control unit (3) designed to carry out the process.

Description

[0001] The content of the German patent application DE 10 2023 205 493.0 is incorporated herein by reference.

[0002] The present invention relates to a method for functional testing of multiple electrical machine components in an injection molding machine. The invention further relates to an injection molding machine.

[0003] Injection molding machines incorporate a multitude of different electrical components, such as heating devices on the plasticizing cylinder and / or in the injection mold, fans, switching valves, conveyors, pressure and / or vacuum generators. Functional testing of these electrical components is often impossible, impossible to perform directly, not cost-effectively, or only with significant technical effort. Malfunctions or even failures of machine components are often only noticed due to their negative impact on the injection molding process, particularly on the quality of the molded parts. This can lead to high levels of scrap and machine downtime. Defective parts can also end up in good batches if the malfunction or failure goes unnoticed.

[0004] The problem of functional testing arises in principle for all electrical machine components of the injection molding machine and is explained below using the example of the heating bands of the plasticizing cylinder. The heating bands, which are attached to the jacket of the plasticizing cylinder, melt the plastic granules. Thermal sensors are regularly installed along the plasticizing cylinder to measure the temperature for temperature control in the respective heating zones. Temperature measurement provides an indirect check of the heating bands' function. A malfunction or failure of a heating band often goes unnoticed, especially if the temperatures are measured elsewhere or if neighboring heating bands are providing thermal energy as a substitute due to temperature control.While the measured temperature at the location of the thermal sensor corresponds to the target values, this has a significant impact on the plasticizing process.

[0005] It is also possible to install fuses with signaling contacts in the respective terminals of the individual heating strips to indicate short circuits or overcurrents. It is also possible to use solid-state relays with diagnostic terminals to switch the heating strips. The latter options allow for more direct measurement, but require additional material and assembly costs and are difficult to reconcile with the other space requirements of the machine components. While fuses with signaling contacts enable short circuit or ground fault detection, or overcurrent detection, they are not suitable for detecting sudden malfunctions, for example, due to a break in the heating coil.

[0006] The object of the present invention is to improve a functional test of electrical components of an injection molding machine, in particular to ensure a simple and reliable functional test with, at the same time, low setup effort.

[0007] This object is achieved by a method for functional testing according to claim 1. This object is also achieved by an injection molding machine having the features specified in claim 13. Advantageous embodiments are the subject of the subclaims.

[0008] The method is used to test the functionality of several electrical machine components of an injection molding machine. The machine components in the injection molding machine are connected to a common power supply for the power supply. A test step is performed for each machine component. In this test step, the machine component assigned to the respective test step is activated and all other machine components connected to the common power supply are deactivated. A current flow is detected in the common power supply while the machine component assigned to the respective test step is activated. A status of the respective machine component is determined from the detected current flow.

[0009] According to the invention, it was recognized that in order to test the functionality of several machine components that are supplied with power via a common supply line, it is sufficient to determine the current flow in the common supply line if the machine components are activated sequentially. This enables economical and efficient functional testing with minimal setup effort. The functional test can, for example, be carried out when the injection molding machine and / or respective parts or components thereof are switched on and / or off. For example, the functional test can be carried out in parallel with the usual switching on and / or off behavior of the machine control system. Additionally or alternatively, it is possible to carry out the functional test repeatedly, for example at regular intervals or quasi-continuously, in particular continuously. This enables close monitoring, in particular real-time monitoring, of the respective machine components.

[0010] The method is suitable for functional testing of all electronic components of the injection molding machine. In particular, it enables simple functional testing of machine components that would otherwise be economically or technically difficult to monitor, such as heating elements contained in the injection mold. The provision of corresponding monitoring sensors, such as fuses with signaling contacts and / or diagnostic terminals, for each of the electronic machine components is not required.

[0011] The process is particularly suitable for machine components whose impact on the rest of the injection molding process is uncritical during brief activation. These can include, for example, actuators for technical and physical systems with corresponding inertia. The following machine components are particularly suitable for functional testing according to this process: - Heating elements, for example, in heating bands of the plasticizing cylinder and / or hot runner heating elements for one or more hot runners of the injection mold. The thermal inertia of the plasticizing cylinder and the injection mold allows for brief sequential activation for functional testing without any practical impact on the injection molding process. - Fans, for example for cooling motors, drive elements, in particular ball screws, control cabinets, power electronics and / or pump rooms. - Switching valves, in particular hydraulic or solenoid valves, for example for supplying cooling water to engines and / or power electronics, switching valves for lubricant circuits, the granulate filling zone and / or oil tanks. - Auxiliary and auxiliary units, in particular pumps, for example for filtration or transfer of media for cooling circuits and / or lubrication. - Conveyors, pressure and / or vacuum generators.

[0012] Components with direct process influence can also be tested using this method. For example, they can be isolated from the system and / or the supplying energy or material flow can be shut off. For example, a pump can be isolated via a switching valve for testing. Feed pumps can also be deactivated to test downstream valves, such as hydraulic valves.

[0013] The machine components that can be supplied with power via the common supply line can be of the same type or different. For example, several heating bands of the plasticizing cylinder or several heating elements of the injection mold can be supplied with power via the common supply line. It is also possible to supply different types of machine components with power via the common supply line.

[0014] The common supply line can be used to supply the machine components with load current and / or control current. For example, the supply line can be used to supply load current for the heating elements. A control current can be used, for example, to switch valves, such as hydraulic or solenoid valves.

[0015] The common supply line can be single-phase or, particularly for supplying load current, multi-phase. The supply line can, for example, be a three-phase alternating current supply line. Different machine components can be connected to different phases of the supply line. If necessary, the current in the respective phases of the supply line, particularly in the respective outer conductor, can be recorded during the verification step. Particularly in the case of control currents, the supply line can also be a direct current line.

[0016] To measure the current, a current sensor, particularly an ammeter, can be integrated into the supply line. A current sensor can be designed to simply detect whether current is flowing or not, or to measure the value of the current flow (e.g., in amperes). A current sensor that measures the value of the current flow is also referred to below as an ammeter. In multi-phase supply lines, a current sensor, particularly an ammeter, can be present for each phase, particularly for each outer conductor.

[0017] The detection, in particular measurement, of the current flow can be performed directly after the power supply, taking into account an offset current, but preferably after fuses or voltage taps, which particularly preferably supply similar machine components. Especially in the case of control circuits, electronic circuit breakers with interfaces to a control unit of the injection molding machine can be used.

[0018] The multiple machine components are preferably connected to the common supply line via respective switching elements. Activating or deactivating the machine components can, in particular, involve switching the respective switching element on or off. The switching elements can, for example, be designed as semiconductor relays. Particularly in the case of a supply line for the control current, the switching elements can be part of a control unit of the injection molding machine.

[0019] The method can in particular be carried out fully automatically by a control unit of the injection molding machine, for example by controlling the corresponding switching elements of the machine components and / or reading one or more current sensors of the common supply line.

[0020] The results of the respective inspection steps can be output to a machine operator. The results of the inspection can be used, in particular, for further maintenance planning.

[0021] According to a preferred aspect of the method, several groups of machine components are tested, each group having a common supply line for supplying power to the respective machine components. The testing of the different groups is preferably carried out in parallel. The machine components of the different groups can be tested for functionality quickly and efficiently. The different groups can, for example, relate to different types of machine components, each of which can be supplied with power via a common supply line. Each group comprises, in particular, several machine components.

[0022] For the functional test, it is sufficient to determine whether or not current flow is present in the respective test step. The detected current flow can therefore be limited to a digital indication of the current flow (current flow "yes / no" or "on / off"). In this way, it is possible to verify whether the respective machine components are fundamentally functional.

[0023] According to a preferred aspect of the method, the current flow is quantified during the verification steps. The current flow is not only recorded digitally, but its respective value is also measured, for example, with an ammeter. This allows more precise statements to be made about the function of the respective machine component. For example, the recorded current flows of the various machine components can be compared with each other to determine deviations. It is also possible to detect deviations from a reference value for the respective machine component.

[0024] According to a preferred aspect of the method, in addition to the current flow, the voltage of the supply line is measured in the respective checking steps. In particular, the respective voltage value is measured. This makes it possible to determine characteristic values, for example an actual power and / or an actual resistance, of the electrical machine component, which enables a more precise statement to be made about the respective functional state of the machine component. In particular, the characteristic values ​​can be determined without the influence of mains fluctuations and compared with a target value. The voltage measurement can be carried out, for example, using a voltmeter specially assigned to the respective common supply line. Particularly preferably, current transformers are connected to an energy detection module or card of a control unit of the injection molding machine in order to additionally detect the voltage of the common supply line.

[0025] According to a preferred aspect of the method, the current flow and / or the voltage and / or parameters determined therefrom, for example the actual resistance and / or the actual power, are compared with a corresponding reference value. By comparing with the reference value, deviations from a target state of the machine component can be detected, in particular for the early detection of impending malfunctions, defects and / or other deviations. Preferably, the comparison with the reference value can be carried out repeatedly over the life cycle of the injection molding machine and / or its respective machine components, in particular periodically, preferably quasi-continuously, in order to detect temporal changes in the relevant parameters.

[0026] The reference value can, for example, be machine-dependent. The reference value can be determined upon delivery of the machine and / or after maintenance. It is also possible to use a design value of the injection molding machine and / or its components as the reference value. This also allows faulty machine conditions to be detected upon delivery and / or after maintenance.

[0027] According to a preferred aspect of the method, a temporal profile of the current flow and / or voltage and / or parameters determined therefrom are determined. The temporal profile can be determined by repeatedly, particularly periodically, performing the functional test. The determined temporal profile allows particularly precise statements about the functional status of the respective machine component, in particular its changes. This allows for early detection of impending defects and / or malfunctions.

[0028] According to a preferred aspect of the method, the electrical machine component is activated in the respective testing step for a diagnostic time interval that is between 1 and 20, in particular between 1 and 10, in particular between 1 and 4, for example, approximately 2, half-waves of the supply voltage. The time period selected in this way is short enough that any practical influence of the activation on other process and operating parameters of the injection molding machine is excluded. The method can be carried out alongside normal operation of the injection molding machine. At the same time, the diagnostic time interval is long enough to make concrete statements about the current flow, the voltage, the actual resistance, and / or the actual power.

[0029] According to a preferred aspect of the method, the diagnostic time interval is one or two half-waves of the supply voltage. This enables particularly short and precise measurements. The method can be carried out particularly efficiently during normal operation of the injection molding machine, in particular quasi-continuously.

[0030] According to a preferred aspect of the method, the diagnostic time interval is an integer multiple of the half-waves of the supply voltage. This enables particularly precise and reproducible measurements, especially without grid influence.

[0031] Particularly preferably, the control can be performed alternately for positive and negative half-waves. This reliably prevents one-sided magnetization of inductive components, especially transformers.

[0032] According to a preferred aspect of the method, the diagnostic time interval is started at a zero crossing of the supply voltage. This allows reproducible measurements without grid influence. The diagnostic time interval can be started, in particular, with the aid of electronic circuits or components for zero-crossing detection, which can be integrated, for example, in a control unit of the injection molding machine.

[0033] Particularly preferably, a coupling relay can be connected to the common supply line, preferably via a diode. The coupling relay can serve as a component for zero-crossing detection of the supply voltage. The coupling relay enables half-wave accurate activation of the machine component assigned to the respective machine step. For example, the coupling relay can be connected to an outer conductor of the supply line via the diode. In the case of multi-phase supply lines, the coupling relay can be used as a coupling relay assigned to one of the outer conductors if the phase positions of the outer conductors are known. The coupling relay can be designed as part of the control unit or separately from it. The coupling relay can, for example, provide a control voltage using which the control unit activates and / or deactivates the machine components.

[0034] According to a preferred aspect of the method, the functional test is performed during ongoing operation of the injection molding machine, in particular quasi-continuously. The functional test does not impair or interrupt normal operation. Functional impairments or malfunctions are reliably detected, even if they only occur during normal operation. In particular, a functional test in which a diagnostic time interval is selected as an integer multiple of the half-waves of the supply voltage enables close-meshed functional testing without a relevant impact on the other process parameters during normal operation. The diagnostic time interval can in particular be between 1 and 20 half-waves, for example one or two half-waves, of the supply voltage.

[0035] For example, the functional test can be carried out periodically, in particular quasi-continuously. It is particularly possible for an operating interval to lie between the respective test steps assigned to a machine component, during which normal operation of the injection molding machine takes place. This makes it possible to further minimize the influence of the functional test on the process parameters. The operating interval is preferably several times longer than the diagnostic time interval, in particular at least ten times, in particular at least fifty times, in particular one hundred times, longer than the diagnostic time interval. The operating interval can, for example, be between 10 s and 5 min, for example between 10 s and 2 min, for example approximately 30 s. The operating interval can, in particular, be an integer multiple of the half-waves of the supply voltage.

[0036] According to a preferred aspect of the method, it comprises a control step in which all machine components connected to the common supply line are deactivated and the current flow in the common supply line is detected. This control step enables a check for permanently conductive connections and resulting fault currents.

[0037] The injection molding machine according to the invention has a plurality of electrical machine components, wherein the machine components in the injection molding machine are connected to a common supply line for power supply. The injection molding machine further comprises a current sensor for detecting electrical current in the common supply line and a control unit. The control unit is designed to carry out the method described above for functional testing of the machine component. The injection molding machine, in particular its control unit, has the corresponding advantages. In particular, functional failures and effects of the machine components can be detected, preferably detected at an early stage, and taken into account in maintenance planning. The injection molding machine, in particular its control unit, can preferably be designed to carry out one or more of the advantageous method aspects described above.

[0038] The current sensor can be designed to digitally display a current flow. Preferably, the current sensor is an ammeter that measures a quantity of the current flow. In multi-phase supply lines, a current sensor, in particular an ammeter, can be provided for each phase, in particular for each outer conductor.

[0039] According to a preferred aspect of the injection molding machine, the machine components are connected to the common supply line via respective switching elements. The switching elements can be switched on and off, in particular, to activate and deactivate the machine components. The switching elements can be designed, in particular, as semiconductor relays that are controlled via the control device.

[0040] To implement the method, the control unit is particularly designed to control the switching elements and / or read the current sensor. The current sensor and / or the switching elements can be contained in the control unit, particularly if the common supply line is designed to supply control current. The switching elements can also be designed separately, for example, as separate semiconductor relays, and controlled by the control unit.

[0041] According to a preferred aspect of the injection molding machine, it comprises several groups, each of which comprises several electrical machine components. Each group has a common supply line for powering the respective machine components with a respective current sensor. The machine components of the different groups can be tested for functionality in parallel. For example, the different groups can comprise different types of machine components, such as heating elements, hydraulic valves, and / or fans. The control unit is preferably designed to perform the functional test for different groups in parallel.

[0042] According to a preferred aspect of the method, the injection molding machine has a voltmeter for measuring the voltage in the common supply line. The voltmeter can, for example, be integrated into a control unit of the injection molding machine. In particular, a current transformer can be connected to an energy detection module of the control system to measure the current flow and voltage in the common supply line. Respective ammeters and / or voltmeters can be provided for multiple supply lines of different groups of machine components.

[0043] According to a preferred aspect of the injection molding machine, it has an output unit for outputting a result of the functional test. In particular, the output unit can have a display for showing operating parameters to a machine operator. For example, a status can be indicated by highlighting a (schematic) representation of the machine component in color. It is also possible to output temporal profiles of the current flow and / or voltage and / or parameters derived therefrom, in particular with reference to a reference value. The output unit can additionally or alternatively have a data interface for outputting a result of the functional test.

[0044] According to a preferred aspect of the injection molding machine, it comprises a circuit, in particular an electronic component, for detecting a zero crossing of the supply voltage of the common supply line, wherein the control unit is configured to activate the machine component assigned to the respective checking step depending on a zero crossing of the supply voltage. With the aid of the zero crossing detection, precise control of the respective machine component in the checking step is ensured, in particular for a diagnostic time interval that is an integer multiple of the half-waves of the supply voltage. The diagnostic time interval preferably starts at a zero crossing of the supply voltage.

[0045] The component for zero-crossing detection can in particular be a coupling relay, which is preferably connected via a diode to an outer conductor of the common supply line.

[0046] Further features, advantages, and details of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings. They show: Fig. 1 schematically shows a group of electrical machine components of an injection moulding machine in the form of heating bands of the plasticising unit, which are supplied with power via a common supply line, Fig. 2 schematically shows a time course of a current flow and a voltage during a testing step for one of the machine components according to Fig. 1, Fig. 3 schematically shows another embodiment of a group of electrical machine components of the injection molding machine in the form of heating elements of the injection mold, Fig. 4 schematically shows a further embodiment of two groups of electrical machine components in the form of fans and solenoid valves, respectively, and Fig. 5 schematically shows a time course of supply voltage and control voltages during a test step.

[0047] Corresponding parts are in the Fig. 1 to 4 are provided with the same reference numerals. Details of the exemplary embodiments explained in more detail below may also constitute an invention in themselves or be part of a subject matter of the invention.

[0048] With reference to the Fig. 1 and Fig. 2, a first embodiment is described. In Fig. 1 schematically shows only those parts of an injection molding machine 1 that are relevant to the illustrated embodiment. Shown in particular are a plasticizing unit 2 and a control unit 3 of the injection molding machine 1. The control unit 3 is, for example, a programmable logic controller.

[0049] The plasticizing unit 2 has a hopper 4 for plastic granules, a plasticizing cylinder 5 for melting the plastic granules, and a nozzle 6 through which the molten plastic granules can be injected into an injection mold (not shown). Heating bands H are arranged along the plasticizing cylinder. i arranged to define the corresponding heating zones. The heating strips H i are a group of electrical machine components of the injection molding machine. The index i = 1, 2, ... denotes here and in the following various machine elements of a group and their associated elements or parameters. In the illustrated embodiment, five heating bands H i shown (ie i = 1, 2, 3, 4, 5). The heating bands H iH to H4 are arranged along the jacket of the plasticizing cylinder 5 and define corresponding jacket heating zones. The heating band H5 is arranged in the area of ​​the nozzle 6 and defines a nozzle heating zone.

[0050] The heating bands H i have heating elements 7 in the form of ohmic resistors. The heating bands H i are connected to a common supply line 9 via respective connecting lines 8. The common supply line 9 serves to supply power to the heating bands H i . The supply line 9 is connected to a three-phase alternating current mains connection and has a neutral conductor N and three outer conductors L1, L2, L3. The heating strips H i are connected to different outer conductors L1, L2, L3 via respective connecting cables 8 in such a way that the load on the supply network is as uniform as possible.

[0051] The heating elements H i are each connected via switching elements S iin the form of semiconductor relays are connected to the common supply line 9. Fuses 10 are also inserted in the respective supply lines 8. The switching elements S i are connected via control lines 11 to a digital output module 12 of the control unit 3 for switching the switching elements S on or off. i by means of a control voltage U S . In Fig. In Figure 1, the control line 11 of switching element S1 is shown in dashed lines, whereas the control lines 11 of switching elements S2 to S5 are shown in dotted lines. This is intended to illustrate, by way of example, that the control lines 11 of switching elements S2 to S5 are de-energized, thus switching elements S2 to S5 are switched off, whereas switching element S1 is activated by a corresponding control current.

[0052] Ammeters 13 are arranged in the outer conductors L1, L2, and L3, respectively, and are connected to an energy detection module 15 of the control unit 3 via measuring lines 14. The ammeters 13 are used to measure a current flow I in the outer conductors L1, L2, and L3. To measure a voltage U in the outer conductors, a voltage tap 16 is connected to the energy detection module 15 of the control unit 3. A voltmeter is implemented using the voltage tap 16.

[0053] To verify the functionality of the individual H1 heating strips, a test step is performed for each heating element. A control step is also performed.

[0054] In the control step, all switching elements S i of the heating bands H connected to the common supply line 9 i off to deactivate the heating bands H i While all heating elements H iare deactivated, the current flow in the outer conductors L1, L2, and L3 is detected. This allows you to check whether there is a permanently conductive connection that could, for example, lead to fault currents.

[0055] The inspection steps for the individual heating elements H i are executed sequentially. For this purpose, the respective heating tape H i by switching on the corresponding switching elements S i activated, while the remaining heating bands H i by switching off the corresponding switching elements S i be deactivated. In Fig. 1 shows the testing step for the heating band H1, in which only the switching element S1 is activated via a corresponding control current in the control line 11. While the respective heating element H i is activated, the current flow I and the voltage U in the corresponding outer conductor are measured.

[0056] An exemplary verification step and its evaluation is presented with reference to Fig. 2 explained in more detail. In Fig. 2 are the control voltage U S and the voltage U and the current flow I are plotted over time t. In addition to the measured voltage U, the supply voltage U V The measured voltage U and the supply voltage U V are plotted in volts (V) and the measured current flow I in amperes (A). The plotted control voltage U S is shown as a unitless digital state of the control output (0, 1). The control voltage U S is initially 0, ie, the corresponding switching element S i is switched off. At time t = 0.1 sec. the control voltage U S and thus the switching element S i activated for a diagnostic time interval T (U S = 1) and then deactivated again. As compared with the supply voltage U Vcan be seen in the corresponding outer conductor, the activation and thus the beginning of the diagnostic time interval T occurs at a zero crossing of the supply voltage U V This can be ensured, for example, by electronic components of the control unit 3 for zero-crossing detection. The diagnostic time interval T is an integer multiple of the half-waves of the supply voltage U V , for example, two half-waves in the illustrated embodiment. This ensures reliable measurement of the current flow I and the voltage U while simultaneously minimizing the impact on the other process properties.

[0057] During activation of the corresponding heating tape H iDuring the diagnostic time interval T, the current flow I and the voltage U in the respective phase conductor are measured. The measurement is performed, for example, with a sampling rate Δt of typically 1 ms or 0.1 ms. The sampling rate Δt is significantly shorter than the diagnostic time interval T, which lasts approximately 20 ms at a typical mains frequency of 50 Hz.

[0058] From the measured current flow I and the voltage U, conclusions can be drawn about the functional status of the respective heating bands, in particular whether the achieved current corresponds to a reference current. With repeated or quasi-continuous checks over the life of the injection molding machine 1, it is thus possible, for example, to check whether the current flow has been affected by damage to the heating bands H i decreases.

[0059] In addition, further parameters of the heating tapes H ibe determined, in particular the actual power P normalized to the nominal effective value of the line-to-line voltage i and the actual resistance R i : Pi=1T∑t=0T[I(t)⋅U(t)⋅Δt]⋅Ueff21T∑t=0T[U(t)2⋅Δt]; Ri=1T∑t=0T[U(t)I(t)⋅Δt].

[0060] Here, U eff the effective voltage of the supply network. These parameters can also be compared with reference values. Furthermore, a temporal progression of these parameters can be recorded and evaluated for early detection of impending defects or malfunctions.

[0061] For half-wave precise control of the heating bands H i via the switching elements S i In the respective checking step, the injection molding machine 1 has a switching arrangement for zero crossing detection of the supply voltage U Vwith an electrical component for this purpose. In the exemplary embodiment shown, a coupling relay 40 is provided for zero crossing detection. The coupling relay 40 is connected via a diode 41 to an outer conductor of the common supply line 9, in this case to the outer conductor L1. The coupling relay 40 is also connected to the neutral conductor N. The outer conductor voltage of the outer conductor L1 against the neutral conductor N is supplied to the coupling relay 40 via the diode 41. Further coupling relays connected to the other outer conductors of the common supply line 9 are not required, since the zero crossings of the other outer conductors can be deduced from the knowledge of the zero crossings of the outer conductor L1 and the phase position of the outer conductors.

[0062] The coupling relay 40 is also connected to a DC voltage U G which is switched as control voltage. The output of the coupling relay 40 with the switched DC voltage UG is connected to the control unit 3. The half-wave precise control using the coupling relay 40 is described below with reference to Fig. 5 described in more detail.

[0063] With reference to Fig. 3 shows a further embodiment of a group of electrical machine components in the form of hot runner heating elements K i of an injection molding tool 20. Again, only those parts of the injection molding machine 1 are shown schematically that are relevant to the embodiment

[0064] The injection mold 20 has, in a known manner, a movable half 21 and a stationary half 22, between which a cavity 23 is formed. Liquid plastic melt can be injected into the cavity 23 via hot runner nozzles 24 of a hot runner system 25. The hot runner nozzles 24 are heated by respective hot runner heating elements K. iHeated. The heated hot runner nozzles 24 prevent the sprue from freezing, thus saving plastic material and reducing rework. Weld lines are also avoided and cycle times are shortened. Reduced injection pressures and / or lower pressure losses can also be achieved. In the illustrated embodiment, two hot runner nozzles 24 with respective hot runner heating elements K1, K2 are shown as examples.

[0065] The connection of the hot runner heating elements K i to a common supply line 9 and the procedure for functional testing corresponds to that with reference to the Fig. 1 and Fig. 2 Described.

[0066] With reference to Fig. Figure 4 shows a further embodiment of two groups of electrical machine components of the injection molding machine 1, wherein again only those parts of the injection molding machine 1 are shown that are relevant to the embodiment. One group comprises fan Fi which are connected to a common supply line 9 for three-phase alternating current in the manner described above.

[0067] The second group includes solenoid valves V i which are connected to a common supply line 30. The common supply line 30 is a DC power supply for a control voltage, for example a 24 V supply. The control voltage is switched by the control unit 3. Corresponding switching elements for activating or deactivating the solenoid valves V i are integrated in the control unit, in particular in a corresponding digital output module 31. Upstream of the control unit 3, in particular the digital output module 31, an ammeter 32 is integrated into the common supply line 30 and connected to the energy detection module 15 via a corresponding measuring line 33. This also allows for the solenoid valves V to be supplied with control current.i carry out an appropriate functional test.

[0068] Since the fans F i and the solenoid valves V i are connected to different respective supply lines 9, 30, their functional testing, in particular the individual testing steps, can be carried out in parallel.

[0069] In Fig. 4 this is indicated by the fact that both the control line 11 of the switching element S3 for the fan F3 and the control line 34 of the solenoid valve V1 are supplied with a control current (dashed line), while this is not the case for the remaining control lines 11, 34.

[0070] The above-described embodiments can be implemented separately in respective injection molding machines or combined in a single injection molding machine. For example, all of the machine components H1, K i , F i and V ibe combined in an injection molding machine and subjected to a corresponding functional test. For example, all of the groups described above can be connected to their own power supply lines. In this case, the different groups can be subjected to a parallel functional test, with particular testing steps for the different groups taking place simultaneously. It is also possible to combine different groups on a common supply line. For example, the heating bands H i and the hot runner heating elements K i be connected to a common supply line and subjected to a common functional test with sequential verification steps. Of course, any other electrical machine components can also be subjected to corresponding functional tests.

[0071] In particular, other electrical machine components can be connected to common supply lines or have their own supply lines.

[0072] The preferred half-wave precise control of the machine components in the respective testing step is exemplified using the Fig. 5. For this purpose, various voltages U in Fig. 5 is plotted against time t. As an example, a circuit for zero crossing detection with coupling relay 40 and diode 41 is assumed, as shown for example in the Fig. 1, Fig. 3 and Fig. 4 is shown.

[0073] Top in Fig. 5 is the supply voltage U V in the outer conductor L1. In the middle of Fig. 5 are the input voltage U EK and the output voltage U AK of the coupling relay. Since the supply voltage U Vof the outer conductor L1 against the neutral conductor N is fed to the coupling relay via the diode, the input voltage U applied to the input of the coupling relay corresponds to EK the positive half-waves of the supply voltage U V The coupling relay switches the DC voltage U G depending on the input voltage U EK The switched DC voltage is the Fig. 5 Output voltage of the coupling relay U shown in the middle AK . Coupling relays can cause a delay in switching, for example by a few milliseconds, which is exemplified in Fig. 5 is shown.

[0074] The output voltage U AK is fed to the control unit, where it is detected. The output voltage U AK is applied, for example, to a digital input of the control unit. The control unit switches the control voltage U S depending on the output voltage U AK. The control unit controls the switching elements S i in such a way that they fire either with the following negative or the following positive half-wave by the control voltage U S is switched accordingly before the zero crossing of the respective half-wave. The switching elements S i , which are preferably designed as semiconductor relays, fire with voltage zero crossing when the control voltage U S is laid out. Below in Fig. 5 is the output voltage U AK , the control voltage U S and the supply voltage U V shown, where only those parts of the control voltage U V are shown as a continuous line, which, when appropriately wired, are supplied to the respective machine component in the testing step.

[0075] Due to the known period of the supply voltage U VA very precise shutdown can be achieved accordingly. Due to the known phase relationships between different phase conductors, a corresponding control can also be provided for machine components connected to other phase conductors, for example, phase conductors L2 or L3.

[0076] The half-wave precision control enables particularly short circuits and thus short diagnostic time intervals T. The diagnostic time intervals T can be implemented with repeatable accuracy, so that the measurements are not distorted. In particular, the diagnostic time interval T can be selected precisely so short that the performance of the machine elements is not affected in a practically relevant way. The test procedure can be performed during normal operation without restricting or influencing normal operation. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2023 205 493.0

[0001]

Claims

[1] Method for functional testing of several electrical machine components (H i ; K i ; F i , V i ) of an injection molding machine (1), wherein the machine components (H i ; K i ; F i , V i ) in the injection moulding machine (1) are connected to a common supply line (9; 30) for power supply, where for each machine component (H i ; K i ; F i , V i ) a verification step is carried out in which - the machine component assigned to the respective inspection step (H i ; K i ; F i , V i ) is activated and all other machine components (H i ; K i ; F i , V i ) can be deactivated, - a current flow (I) in the common supply line (9; 30) is detected, while the machine components (H i ; K i ; F i , V i ) is activated, and - from the recorded current flow (I) a state of the respective machine component (H i ; K i ; F i , V i ) is determined. [2] Method according to claim 1, characterized by that several groups of machine components (H i ; K i ; F i , V i ), in particular in parallel, whereby each group has a common supply line (9; 30) for the power supply of the respective machine components (H i ; K i ; F i , V i ) is present. [3] Method according to one of the preceding claims, characterized by that the current flow (I) is quantified in the verification steps. [4] Method according to one of the preceding claims, characterized by that in addition to the current flow (I) the voltage (U) of the supply line (9; 30) is measured. [5] Method according to one of claims 3 or 4, characterized by that the current flow (I) and / or the voltage (U) and / or parameters determined therefrom (P i , R i ) must be compared with a corresponding reference value. [6] Method according to one of claims 3 to 5, characterized by that a temporal course of the current flow (I) and / or the voltage (U) and / or parameters determined therefrom (P i , R i ) is determined. [7] Method according to one of the preceding claims, characterized by that the electrical machine component (H i ; K i ; F i , V i) is activated in the respective check step for a diagnostic time interval (T) which is between 1 and 20, in particular between 1 and 10, in particular between 1 and 4, for example about 2, half-waves of the supply voltage (U V ) amounts. [8] Method according to claim 7, characterized by that the diagnostic interval (T) is one or two half-waves of the supply voltage (U V ) amounts. [9] Method according to claim 7 or 8, characterized by that the diagnostic time interval (T) is an integer multiple of the half-waves of the supply voltage (U V ) is. [10] Method according to one of claims 7 to 9, characterized by that the diagnostic time interval (T) is reached when the supply voltage (U V ) starts. [11] Method according to one of the preceding claims, characterized by that the functional test, in particular quasi-continuously, is carried out during normal operation of the injection moulding machine. [12] Method according to one of the preceding claims, characterized by a control step in which all machine components (H i ; K i ; F i , V i ) are deactivated and the current flow (I) in the common supply line (9; 30) is detected. [13] Injection molding machine (1), comprising - several electrical machine components (H i ; K i ; F i , V i ), which are connected to a common supply line (9; 30) in the injection moulding machine (1) for power supply, - a current sensor (13; 32) for detecting a current flow (I) in the common supply line (9; 30), and - a control unit (3) which is designed to carry out a method for functional testing of the machine components (H i ; K i ; F i , V i ), whereby for each machine component (H i ; Ki ; F i , V i ) a verification step is carried out in which -- the machine component assigned to the respective inspection step (H i ; K i ; F i , V i ) is activated and all other machine components (H i ; K i ; F i , V i ) can be deactivated, -- a current flow (I) in the common supply line (9; 30) is detected by means of the current sensor (13; 32), while the machine components (H i ; K i ; F i , V i ) is activated, and - from the recorded current flow (I) a state of the respective machine component (H i ; K i ; F i , V i ) is determined. [14] Injection molding machine (1) according to claim 13, characterized by that the machine components (Hi ; K i ; F i , V i ) via respective switching elements (S i ) are connected to the common supply line (9; 30). [15] Injection molding machine (1) according to one of claims 13 or 14, characterized by several groups of several electrical machine components (H i ; K i ; F i , V i ), whereby each group has a common supply line (9: 30) for the power supply of the respective machine components (H i ; K i ; F i , V i ) with a respective current sensor (13; 32). [16] Injection molding machine (1) according to one of claims 13 to 15, characterized by a voltmeter (16) for measuring the voltage (U) in the common supply line (9; 30). [17] Injection molding machine (1) according to one of claims 13 to 16, characterized by an output unit for outputting a result of the functional test. [18] Injection molding machine (1) according to one of claims 13 to 17, characterized by a circuit, in particular an electronic component, for detecting a zero crossing of the supply voltage (U V ) of the common supply line (9; 30), wherein the control unit (3) is designed to be dependent on a zero crossing of the supply voltage (U V ) the machine component assigned to the respective inspection step (H i ; K i ; F i , V i ) to activate.

Images