METHOD FOR AVOIDING PARALLELITY OF PIPE LOADS IN A PLASTICS PROCESSING MACHINE, IN PARTICULAR INJECTION MOLDING MACHINE OR MOLDING MACHINE, AS WELL AS PLASTICS PROCESSING PLANT

Description

[0001] The invention relates to a method for avoiding parallelism of load peaks in a plastics processing machine, in particular an injection molding machine or a forming machine, as well as in a plastics processing plant, as described in claims 1 to 11.

[0002] Electricity costs are among the most significant ongoing operating expenses for production equipment in plastics technology, particularly injection molding machines and peripheral devices for temperature control, heating, drying, and / or cooling of tools, injection molding machines, and / or the material to be processed, and thus for the production of injection-molded parts. Energy suppliers generally use a time interval of 15 minutes as the basis for calculating the power consumption. However, with power-price-dependent electricity contracts, costs arise not only for the actual energy consumed. In addition, the highest monthly or annual power peak consumed is determined and invoiced. This portion of the power price can amount to up to 30 percent of the total electricity costs. Therefore, electricity costs can be reduced not only by reducing electricity consumption but also by reducing short-term power peaks.

[0003] Since the injection molding process is designed as a discontinuous production process with different phases, a cost-optimal, and therefore constant, load reduction cannot be achieved.

[0004] Current solutions address load management during the ramp-up of production resources, with the load management system being subject to specifications typically based on business criteria and the knowledge and priority of production orders. Therefore, linking this type of holistic peak load management to an ERP (Enterprise Resource Planning) system or MES (Manufacturing Execution System) is essential.

[0005] DE 10 2012 111 046 A1 pursues a different approach. It describes a method for limiting the maximum power consumption of a production machine, in particular an injection molding machine. An injection molding machine typically consists of a large number of power consumers, referred to in the present method as units or unit groups, which, depending on their functionality, can be operated temporarily with reduced power consumption without causing a loss of quality in the product being manufactured. The method is particularly advantageous when starting up (heating up the individual units / unit groups) of an injection molding machine, e.g. after a weekend, since the reduced power consumption of units / unit groups to limit the current total power consumption is noticeable as a longer heat-up phase, but has no influence on product quality.The method can also be applied during normal operation of the injection molding machine, i.e., during part production, specifically to limit the use of existing heating elements on the machine (cylinder heating). However, the disadvantage is that only the components of the injection molding machine are taken into account for power consumption, and the other peripheral devices required for the operation of the injection molding machine are not included in any way. This can often lead to overlaps in energy consumption, especially in the areas of the injection molding machine's highest power consumption.

[0006] Furthermore, DE 10 2012 104 493 A1 discloses a higher-level machine-independent Energy management system ("master system")known to be used to coordinate the electrical power consumption of multiple production machines. In this case, too, the master system is connected to multiple production machines and intervenes, at least in a controlling, and if necessary also in a regulating, way in the power consumption for the energy supply of each of the individual production machines. The document refers to plastics processing machines, not to the necessary peripherals and auxiliary devices, which operate independently and autonomously from the production machine.

[0007] Furthermore, AT 12 820 U1 discloses a method for operating a group of injection molding machines, in which the energy or power requirement of each injection molding machine belonging to a group is monitored by a group controller. The group controller continuously calculates the total energy or power requirement of the group, and when a predetermined limit is reached or exceeded, an energy or power limitation or shift can be applied to each injection molding machine belonging to the group in order to prevent or stop a predetermined peak value from being exceeded. A disadvantage of this method is the temporary extension of cycle times of individual injection molding machines in the group, since machine cycles typically differ and a cycle shift of an injection molding machine must therefore be applied repeatedly.A postponement is equivalent to a cycle extension, which on the one hand reduces the efficiency of an injection molding machine and on the other hand results in different cycle times for the production of the same parts and can therefore have an impact on the quality of the parts.

[0008] Available solutions on the market represent far-reaching and comprehensive systems for peak load management of a machine, a work cell, multiple machines, multiple work cells, or all of a company's production resources. Devices are known that measure the power requirements of production resources and transmit them to a dedicated central control system for load management. Load management can differentiate between, or can be configured to, load-shifting, load-reducing, load-flexible, and load-expanding control measures. Depending on the control measure, corresponding control signals are sent to the production resources participating in load management.

[0009] The disadvantage of this method is the high investment and installation costs, since all participants, especially production resources, must be connected to the load management system separately and equipped with additional resources.

[0010] Such systems are effective in optimizing peak loads when starting up production resources, since parallelism of the load can be prevented by switching on production resources earlier or later.

[0011] However, such systems do not result in measurable energy savings during regular production operation of the production equipment, since it is not possible to intervene directly in the control process of the production equipment.

[0012] Furthermore, DE102013009607A1 describes a method for operating energy consumers of an injection molding machine, whereby each energy consumer is assigned a partial energy consumption. A maximum energy consumption is defined for all energy consumers combined, whereby, to prevent the defined maximum energy consumption from being exceeded, no energy is initially allocated to at least one energy consumer. This method only works in cases where the energy consumption of the participating consumers is known and directly controllable. This is the case for an injection molding machine with typical component-integrated consumers, such as the drive unit, heating elements in the mold (hot runners), heating devices on the plasticizing cylinder, and a handling robot integrated into the control and drive systems, since these components are components of the system or injection molding machine with known performance characteristics.

[0013] EP2674277A1 discloses an injection molding machine comprising a cylinder to which granulate is fed, wherein a plurality of heaters heat the cylinder. A plurality of temperature sensors measure the respective temperatures of the different heating zones of the cylinder. A controller is provided that independently controls the electrical energy supplied to the heaters based on a temperature deviation of the measured temperature of the temperature sensors from a target temperature. The controller sets the total electrical power supplied to the heaters.

[0014] Furthermore, WO2013143585A1 describes a method and device for supporting the creation of an energy-efficient control sequence of an industrial plant or part of an industrial plant, consisting of plant components, in which plant components can have logical dependencies on one or more other plant components.

[0015] EP3255513A1 describes a method for real-time determination of the power curve and / or energy flow of a drive device with multiple electric drives connected to one another via a common intermediate circuit. The method comprises the following steps: - Determining the respective electric drive power and the electric drives (A i ) and determining the power requirement (PN ) as a function of the sum of the determined electric drive powers of the drives electrically connected to one another via the common intermediate circuit (Z).

[0016] US2014163763A1 describes a method for scheduling device operation. The method includes receiving a plurality of signals. Each signal has a peak time value. Based on the plurality of signals, a predicted peak time value is determined. The predicted peak time value can be used to determine when to perform a device operation to avoid operating the device during a peak time period.

[0017] Furthermore, EP3915755A2 discloses a management method for controlling and / or regulating an entire system with at least two system components connected to an intermediate circuit.By determining the power requirement and / or the power feedback of at least two parts of the system and analyzing them in relation to one another, and then controlling and regulating the total power requirement and / or the total power feedback by controlling and / or regulating at least one part of the system in such a way that the total power requirement and / or the total power feedback of the entire system at at least one specific point in time or within at least one specific time interval is less than or equal to at least one predetermined value, preferably less than or equal to a greatest maximum of the power requirement and / or the power feedback of the part of the system that has the greatest maximum of the power requirement and / or the power feedback at the at least one specific point in time or within the at least one specific time interval, energy-optimized operation of the system is ensured.

[0018] The disadvantage of the above-mentioned state of the art is that systems are described whose energy consumption of the participating consumers must always be known.

[0019] The object of the invention is to provide a method for avoiding parallel load peaks of a plastics processing machine, in particular an injection molding machine or forming machine, and other production means involved in the production, wherein the injection molding machine or forming machine or an external work cell control transmits control signals or operating states to these other production means so that they carry out appropriate load management to avoid parallel load peaks.

[0020] This object is achieved by the invention. Further solutions according to the invention are described in the subclaims.

[0021] The method according to the invention for avoiding parallel load peaks of a plastics processing machine, in particular an injection molding machine and at least one means of production, is characterized in that the injection molding machine or the external work cell control sends one or more leading control signals or internal operating states with increased load requirements to the means of production, so that the self-sufficient (independent) means of production carry out a load shift, load reduction or load shedding at the times of the increased load requirement of the injection molding machine.

[0022] An advantage here is that all production resources are taken into account for energy management, with these resources adjusting their energy requirements based on the injection molding machine's specifications to avoid any accumulation. Another advantage is that load activities are controlled or regulated by the production resources in such a way that they take place during those production phases of the injection molding machine in which the load level is low, or at least below a specified or self-determined load level threshold. In particular, heating elements, for example, can be preheated, reduced, or delayed in order to be deactivated or supplied with less energy during phases where the load level exceeds the specified threshold.

[0023] The optional presence and use of an external work cell controller is advantageous. This forms a kind of connection point between the injection molding machine and other production equipment, especially peripheral devices such as temperature control units, hot runner controllers, cooling units, flow controllers, granulate dryers, mold dryers, dosing devices, robots, automation systems, etc., i.e., a production cell. Since the composition of production cells can change depending on the plastic part being produced, a higher-level logic system in the form of an external work cell controller is advantageous for logically integrating the injection molding machine and peripheral devices. In this case, the work cell controller is responsible for determining the currently connected peripheral devices and for forwarding any control signals and operating states.After detecting a new peripheral device (production resource), the work cell controller contacts it and receives, among other things, the device type and possible specifications. Part of the specification could be the load requirements of the entire device or even individual components of the device.

[0024] A work cell control system with extended logic for load management of peripheral devices is advantageous. The work cell control system takes over the basic load control of the injection molding machine and expands it so that the accumulated loads of the peripheral devices and the current load of the injection molding machine never exceed the injection molding machine's load peak.

[0025] However, measures that allow the load level for activating the control signal(s) or changing the internal operating state(s) for transmitting or indicating the presence of a load peak in the injection molding machine or work cell control system to be freely selectable, adjustable, or automatically determined are also advantageous. This allows the operator of the machine or system to actively intervene in load management if they have the necessary knowledge, or to have this done automatically by the injection molding machine or the external work cell control system.

[0026] Also advantageous are measures whereby the injection molding machine continuously calculates or measures the existing load level during one or more working cycles, particularly between two consecutive mold closing operations, and stores this data for subsequent analysis, particularly for determining the switching of the control signal(s) or the internal operating states. The recorded values ​​can be displayed in diagram form, averaged or unaveraged, to allow the operator to manually define the switching points for "high" load requirements or at least graphically. Typically, however, the switching points of the control signal(s) or the internal operating state(s) are self-determined.

[0027] Also advantageous are measures in which an external work cell controller continuously measures the existing load level during one or more injection molding machine cycles, particularly between two consecutive mold closing operations, and stores it for subsequent analysis, particularly for determining the switching of the control signal(s) or the internal operating states. The recorded values ​​are used for the self-determination of the switching points of the control signal(s) or the internal operating states.

[0028] However, measures where the injection molding machine or an external work cell control system can also transmit or indicate the control signal(s) or internal operating states with increased load requirements in advance are also advantageous, so that the autonomous production resources can prepare appropriate load control actions. This is advantageous because the corresponding production resources can take sufficient time to reorganize the control or regulation process, preventing sudden activation and deactivation of control elements and any deviations in the control process.

[0029] Advantageous are measures in which the autonomous production resources are also designed to be self-learning and can anticipate the occurrence of a load peak in the injection molding machine and automatically carry out load control, preferably after monitoring the behavior of the control signal(s) or the internal operating states in a work cycle of the injection molding machine at least once. The advantage here is that better control behavior can be achieved, for example, by switching on slower control elements, e.g. heaters, ahead of time and then switching them off for a short time during the duration of the increased load requirement of the injection molding machine. This load distribution can of course only be used optionally. Likewise, the peripheral device could solely perform a load shift in order to limit a higher switching frequency of the elements to be controlled.

[0030] Advantageous measures include self-determination of the switching points of the control signal(s) or the internal operating states depending on the load level by the injection molding machine or an external work cell controller, whereby the cumulative presence of the control signal(s) or the internal operating states for load peaks does not exceed approximately 15% to 25% of a total cycle of the injection molding machine. For operators of injection molding machines and peripheral devices, self-determination of the load level is very practical because no knowledge of the process or this specific functionality of the devices is required. With self-determination, the presence of the control signal(s) or the internal operating states for load peaks is limited to a duration of approximately 15% to 25% of a total cycle of the injection molding machine.This requirement ensures the process reliability of the peripheral devices, as sufficient time is available for the activation of the load-reducing components and postponed processes can be caught up on.

[0031] Advantageous measures include the injection molding machine reporting the difference between the maximum peak load in a work cycle and the currently calculated or measured load, or another value that directly or indirectly indicates the currently unused load requirement, to a work cell control system. Other physical values ​​that directly or indirectly indicate the currently unused load requirement of the injection molding machine can also be reported to an external work cell control system.

[0032] Alternatively, the difference between the maximum load peak in a working cycle of the injection molding machine and the currently measured load can be determined directly in an external work cell control in order to calculate the currently unused load requirement of the injection molding machine.

[0033] The advantage of this configuration is that an external work cell controller can implement more advanced load management, which specifically enables or disables peripheral devices for load reductions. The load reduction of a peripheral device can either be specified in the device configuration or set by the operator. Optionally, the load reduction can also be calculated or measured. The targeted, possibly sequential activation of peripheral devices ensures that the maximum load peak of the injection molding machine is not exceeded by the current load of the machine and the cumulative load of all peripheral devices after the load peak.

[0034] Advantageous are measures in which an external work cell control determines the difference between the maximum load peak in a work cycle of the injection molding machine and the currently measured load of the injection molding machine and from this calculates the currently unused load requirement of the injection molding machine.

[0035] However, measures in which an external work cell control system transmits the control signal(s) to the autonomous production equipment at different times are also advantageous, depending on the load reduction of the active production equipment in question, so that the total load of the production equipment does not exceed the load requirement not required by the injection molding machine.

[0036] Furthermore, the object of the invention is achieved by a plastics processing system in which the injection molding machine or forming machine and / or an external work cell control system is configured to carry out the method according to one of claims 1 to 10, and the additional production resources involved allow the described load control. It is thus advantageous to prevent the overlap of load peaks of an injection molding machine and the production resources involved in production.

[0037] The invention is explained in more detail with reference to an embodiment shown in the drawings, whereby the invention is not limited to the described embodiment, but is transferable to equivalent solutions.

[0038] They show: Fig. 1 an overview of a plastics processing industrial plant, in a simplified, schematic representation; Fig. 2 a schematic representation of an overall cycle of energy consumption of the primary means of production, in particular the injection molding machine, in a simplified, schematic representation Fig. 3 a schematic representation of the overall cycle according to Fig. 2with illustrated signal times for transmission to the production equipment, in a simplified, schematic representation; Fig. 4 a schematic representation of a plastics processing plant with higher-level work cell controls, in a simplified, schematic representation; Fig. 5 an energy diagram showing the start-up, startup and regular operation of an injection molding machine with the respective average energy consumption in a respective evaluation period of 5 seconds in a simplified, schematic representation; Fig. 6 an energy diagram showing the start-up, startup and regular operation of an injection molding machine with the respective maximum energy consumption in a respective evaluation period of 5 seconds in a simplified, schematic representation;

[0039] By way of introduction, it should be noted that in the various embodiments, identical parts are provided with identical reference symbols or component designations, whereby the disclosures contained in the entire description can be applied mutatis mutandis to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the described figure and, if the position changes, is to be applied mutatis mutandis to the new position. Individual features or combinations of features from the illustrated and described embodiments can also represent independent inventive solutions in their own right.

[0040] In the Fig. 11 shows an industrial plant, in particular a work cell 1 or production cell 1 for injection molding applications, in which the individual production means 2 or devices 2 for producing one or more products / semi-finished products or injection-molded parts 3 are interconnected in the work cell 1. An injection molding machine 4 is preferably used as the processing machine, to which a robot 5 or automatic handling device is assigned for removing the produced injection-molded part 3, wherein the injection-molded part 3 is removed from an opening mold 7 by a removal device 6, in particular a gripper equipped with gripping tongs or suction nozzles, and placed on a device, for example a conveyor belt 8. In order to produce an injection-molded part 3, plastic granulate 9 is fed to the injection molding machine 4 via a granulate conveyor 10 and possibly via a dosing device 11.A temperature control device 13a and / or cooling device 13b can be used to keep the injection mold at operating temperature by supplying a temperature control medium, or to heat or cool it accordingly, thus enabling optimal processing of the plastic granulate 9, which must be plasticized for injection into the mold 7. In addition, the system has a monitoring device 15, in particular a camera system, to carry out automatic quality control of the produced product 3. To enable the individual devices to be set up or programmed, they have corresponding control electronics or control logic, which are entered and displayed via displays 16 or controllers 17 arranged on the devices. For the sake of completeness, it should also be mentioned that all devices are equipped with corresponding lines, in particular power supplies, network lines, liquid supply lines, material lines, etc.which are not shown in the illustration shown for the sake of clarity.

[0041] A production cell 1 for the manufacture of injection-molded parts 3 therefore consists not only of the production machine 4, but also of a wide variety of production resources 2, in particular peripheral devices, e.g. temperature control devices 13a and / or cooling devices 13b, heating channel systems, granulate dryers 12, tool dryers, dosing devices 11, robots 5, automation systems, etc. The production resources 2 generally use internal sensors, i.e. sensors directly integrated into the control system of the production resource 2, or external sensors, which in turn are connected to the control logic of the production resource 2 via direct wiring or a device interface. These sensors transmit analog or discrete states, which subsequently trigger actuators in the production resource 2 in order to effect the behavior necessary for the functionality of the production resource 2.

[0042] In all cases, the production resources 2 operate independently of each other in terms of load requirements and call up the internal consumers according to the requirements of their own control logic and to fulfill the respective functionality. Furthermore, the state of the art is that the production resources 2 also operate independently of each other in terms of load requirements, especially energy consumption, even if they are optionally linked on the control side via discrete signals or data interfaces.

[0043] The primary means of production 2 of the production cell 1 for the production of injection-molded parts 3 is the injection molding machine 4, as shown in a performance diagram in Fig. 2 was presented.

[0044] The injection molding machine 4 determines, on the one hand, the overall production cycle 18 and influences the behavior of the other production means 2 in the production cell 1 through the different production phases 19, in particular opening 19a and closing 19b of the mold, clamping force buildup 19c and clamping force reduction 19d, dosing 19e with plasticizing of the material to be processed, injection 19f, cooling 19g, ejector movement forward 19h and ejector movement back 19i. For the sake of completeness, it is mentioned that such cycles, in particular overall cycles 18, are repeated and that other processes not shown can be included in this overall cycle 18.

[0045] In a constant control operation of the injection molding machine 4, ie when injection molded parts 3 are produced, the load reduction curve 20 approaches a relatively deterministic form, which is, however, characterized by a few load peaks and relatively long phases of lower load consumption, as can be seen from Fig. 2 The load requirement, in particular the load reduction curve 20, depends very strongly on the machine size, equipment, and the clamped mold. For example, injection molding machines 4 with a lower clamping force can have a lower load peak when moving the movable mold half than an injection molding machine 4 with a very high clamping force and a correspondingly heavier movable mold half. The load reduction curve 20 also depends very strongly on the mechanical and electrical design of the injection molding machine 4. A phase with a particularly low load reduction in each injection molding cycle is the cooling time 19g.

[0046] The other production resources 2 of a production cell 1 exhibit significantly more inconsistent patterns, with the load reduction of an individual device typically being significantly lower than the load peak 21 of the injection molding machine 4. Since all production resources 2 operate independently of one another in terms of load requirements, parallelism in load requirements inevitably occurs.

[0047] According to the invention, it is provided that the injection molding machine 4 or forming machine has a leading control signal 22, or an internal operating state 22 with increased load requirement, as shown schematically in Fig. 3shown, to the production means 2, so that at least one production means carries out a load shift, load reduction or load shedding at the times of the increased load requirement of the injection molding machine 4, i.e. that the injection molding machine 4 transmits the control signal 22 or the information 22 to the corresponding production means 2 or to all production means 2 at a time 23 of the work step or the production phase 19 carried out at a later time 24, so that they adapt their regulations or control accordingly to the expected load requirement, in particular postpone or reduce it. Depending on the subsequent production phase 19, the leading time period 25 can be different, as shown schematically in Fig. 3 was presented.

[0048] This is achieved, among other things, by ensuring that the energy requirements and load volume of the injection molding machine are predictable to a certain extent during normal operation, and this knowledge can be used by the connected production equipment 2 for better load minimization or shifting. Normal operation is the state of machine 4 and production equipment 2 after each startup or switch-on, i.e., typically when injection-molded parts 3 are being produced.

[0049] In this case, it is necessary that a data connection of the injection molding machine 4 is provided to at least one production means 2, ideally to as many production means 2 as possible that are necessary for the operation of the respective mold 7, in order to transmit the corresponding information 22. In principle, however, it is also possible for a correspondingly set or recorded overall cycle 18 to be stored or saved in the production means 2, so that only a control signal 22 is transmitted in advance, i.e. a time period 25 before the production phase 19 with load peak 21 is carried out, since the production means 2 can determine the upcoming or next production phase 19 from the stored overall cycle 18.In the simplest case, the data connection is designed as a discrete signal line 22 to transmit at least one signal from the injection molding machine 4 to the at least one and / or other connected production means 2. Another embodiment provides for the transmission of several discrete signals 22, which are assigned, for example, to different operating states.

[0050] A further embodiment in the spirit of Industry 4.0 provides for a significantly more extensive data connection. From a data processing perspective, one example of this is the combination of production resources 2, including the injection molding machine 4, into a logical work cell 1, as envisioned in the "Wittmann 4.0" system. The "Wittmann 4.0" system and the associated methods enable, for example, automatic recognition and logical combination of the production resources 2 into a work cell 1 via a data connection, as can be seen, for example, in WO 2019 / 018868 A. Several work cell controllers 26 (a to d) can be arranged side by side (horizontally) and operate independently of one another, or arranged vertically (in a tree structure) consisting of multiple levels.

[0051] The injection molding machine 4 represents the primary production means 2 in the following load analysis and the control algorithm. The sequence of the individual process steps of the injection molding machine 4 directly determines the occurrence of non-shiftable load peaks 21. Each additional production means 2 can, to a certain extent, accept a more flexible load reduction, whereby this can be a shift, a pre-sequence or a reduction, as shown schematically in Fig. 3 to another means of production 2 in order to illustrate the invention.

[0052] When the following discussion refers to "injection molding machine 4", this meansalso means a form of implementation in which the signals 22 of the injection molding machine are transmitted to a higher-level controller, e.g. work cell controller 26, which forwards these directly to the production equipment 2 or uses its own logic for processing the signals 22 of the injection molding machine 4 and transmitting them to the production equipment 2. The logic for controlling the control signals 22 and any other information 22 (sequence, peak load level, etc.) is called load management. In one form of the invention, the load management transmits a control signal 22 to the production equipment 2 when a load peak 21 occurs. The control signal 22 is sent out in advance if possible so that the production equipment 2 can prepare appropriate load control actions.

[0053] The period for the leading signal 22 can be approximately in the range of 1 to 0.5 seconds. This time or duration 25 also serves to compensate for various delays on the transmission lines 27. The control signal 22 indicates the presence of a load peak 21 that exceeds a certain freely selectable, adjustable, or self-determined load level 28. A self-determined load level 28 must be selected such that sufficient load reduction time remains for the other production resources 2. Of course, this level is also influenced by the number of connected production resources 2. In this respect, the presence of the "Wittmann 4.0" device is advantageous, since in this case, the connected production resources 2 are known to the work cell control 26 and also to the injection molding machine 4 and can be immediately incorporated into the calculation.

[0054] In principle, the load level 28 can be selected such that the duration of exceeding this load level 28 and thus the duration of the control signal 22 for load peaks 21 does not exceed approximately 15% to 25% of a total cycle of the injection molding machine 4. If the control signal 22 is present for a longer period, it must be assumed that the production equipment 2 may have to ignore the control signal 22 and independently switch on the internal load consumers in order not to jeopardize process control. If the level or load level 28 is selected correctly, the production equipment 2 switches off the internal load consumers, delays switching on, or reduces the load, depending on the technical possibility.

[0055] It is also possible for the production means 2 to be designed to be self-learning and to be able to anticipate the occurrence of a load peak 21 on the injection molding machine 4, since the temporal behavior in automatic operation of the injection molding machine 4 is relatively deterministic. With predictive control in the production means 2, load generators, e.g. heating elements, can switch the load on and then off again shortly before the likely occurrence of a load peak 21 on the injection molding machine 4. Due to the energetic inertia of heating elements or, in general, of thermocouples, preheating can thus be achieved before the normal control sequence is started after the load on the injection molding machine 4 drops, and the target state of the control parameter can thus be reached more quickly.

[0056] For example, it is therefore possible that when a signal 22 is sent from the injection molding machine 4 or the work cell controller 26 to a temperature control device 13a, the latter is informed that the next production phase 19 is above the preset load level 28, so that any pending control processes in the temperature control device 13a should be brought forward, postponed, or split up if the corresponding parameter settings in the temperature control device 13a permit this. Thus, after receiving the signal 22, the temperature control device 13a can, for example, preheat its heating elements and switch them off or reduce them during the production phase 19 in which the load level 28 is exceeded, in order to subsequently complete the control process. This ensures that in those areas in which the load level 28 is exceeded, the other production resources 2 attempt to preferably not produce any or only produce as much of the required production as possible.necessarily only consume a small amount of energy in order to prevent further accumulation of energy consumption.

[0057] The load management can also report the level of the load peak 21 or the difference between the load peak 21 and the base load or another value that directly or indirectly indicates the subsequent load requirement to the production equipment 2. The load peak 21 can be determined either by calculation or through a previous performance measurement. The difference between the load peak 21 and the base load (load reserve) is also calculated or determined by measurement. Typically, the load reserve is significantly greater than the load consumption of an individual production equipment 2. This means that in the phases in which the injection molding machine 4 does not cause any load peaks 21, several production equipment 2 can run simultaneously and still not reach the maximum peak load level 21 of the injection molding machine 4.It is therefore advantageous if the work processes of the additional production resources 2 are relocated to those production areas 19 in which no load peaks 21 are to be expected from the injection molding machine.

[0058] In a further embodiment, the production resources 2 can be addressed sequentially for load reduction after the load drop of the injection molding machine 4, i.e., for example, after the load peak 21 is undershot, a corresponding further signal 29 with corresponding information is sent out. The sequence is determined statically or dynamically by a given priority of the individual production resources 2. This can be determined by the degree of process relevance of the production resource 2 or the level of load reduction. The load reserve is passed on to the production resources 2 in the order of priority, whereby these deduct their own load requirement from the load reserve when load is required and pass it on to the subsequent production resources 2. In this case, the transfer of the load reserve must be ordered cyclically by the injection molding machine 4.

[0059] The method is based on the ability of the individual production resources 2 to have load-influenceable components and to influence the internal process using corresponding control signals 22, 29. The higher the number of such load-influenceable components in a production resource 2, the greater the probability of obtaining a response from the production resource 2 that is desired by the injection molding machine 4 and the load management.

[0060] Furthermore, in Fig. 5 an average energy consumption was shown, whereas in Fig. 6 a non-averaged energy consumption is shown.

[0061] When considering the energy consumption of production resources 2, in particular a primary production resource 2, e.g., an injection molding machine 4, average values ​​are generally assumed. Typically, an evaluation period 30 of 15 minutes is used, since utility companies in many countries also use the average consumption for the respective 15-minute period when billing electricity consumption. From this perspective, the start-up 31 of the injection molding machine 4 requires the most energy. After production has started 32 and a constant production cycle has been reached 33, the average consumption assumes a lower average load level. Fig. 5represents the average consumption with an evaluation period of 30 seconds. For a longer average calculation, for example, when applying the usual evaluation period of 30 minutes out of 15 minutes, the values ​​are presented in a more smoothed manner. Specifically, the stable production phase 19 will have a lower value than in Fig. 6 The peak load management of commercially available systems therefore also focuses on avoiding simultaneous phases with a high average energy level, particularly through load shifting, load reduction, load shedding, and load sharing.

[0062] Fig. 6 illustrates the energy consumption of a primary means of production 2, e.g. an injection moulding machine 4, without filtration, which results in a very different picture.

[0063] The load peaks 21 become particularly pronounced during normal production cycles 33. It is evident that the highest load peaks 21 do not occur during the start-up phase 32 of the injection molding machine 4, but only during regular operation or the machine's production cycle 33. This is important because the highest load peak 21 in the company's electricity demand determines the amount of the grid usage fee charged by the grid operator or electricity supplier. In many cases, the costs of the grid usage fee exceed the costs of current electricity consumption. It is therefore advantageous to prevent the overlap of load peaks 21 of primary production resources, e.g., an injection molding machine 4, and the production resources 2 involved in production.

[0064] For the sake of completeness, it should be noted that this view does not include or depict the other necessary connections between the injection molding machine 4, the mold 7, the production equipment 2, or other components important for production. These are typically electrical and / or water and / or hydraulic and / or air connections and are essential for the correct functionality of the entire production cell.

[0065] It can therefore be stated that according to the invention a method for avoiding parallelism of load peaks 21 of a plastics processing machine, in particular injection molding machine 4 or forming machine and at least one production means 2, such as, for example, temperature control devices 13a, hot runner systems, cooling devices 13b, flow controllers 14, granulate dryers 12, tool dryers, dosing devices 11, robots 5, automation systems, etc., wherein the injection molding machine 4 is connected via an electrical line 27 or data line 27 to the at least one production means 2 directly or indirectly via an external work cell control 26, wherein the injection molding machine 4 or shaping machine sends a leading control signal 22 or an internal operating state 22 with increased load requirement to the production means 2, so that the at least one production means 2 carries out a load shift, load reduction or load shedding at the times 24 of the increased load requirement of the injection molding machine 4. It is thus advantageous to prevent the overlap of load peaks 21 of an injection molding machine 4 and the production means 2 involved in production.

[0066] For the sake of clarity, it is pointed out that the invention is not limited to the illustrated embodiments, but may also include further designs and structures. The scope of the invention is defined in the appended claims.

Claims

1. Method for avoiding parallel occurrence of load peaks (21) of a plastics processing machine, in particular an injection-molding machine (4) and at least one stand-alone production resource operated with its own control system (2), for example a temperature control unit (13a), hot runner system, cooling unit (13b), flow controller (14), granule dryer (12), mold dryer, metering device (11), robot (5), automation system, etc., wherein the injection-molding machine (4) is connected via an electrical line (27) or data line (27) to the at least one independent production resource (2) directly or indirectly via an external work cell controller (26), wherein the injection-molding machine (4) or the external work cell controller (26) transmits one or several leading control signals (22) or internal operating states (22) with increased load requirement to the production resource (2) so that the independent production resource (2) performs a load shift, load reduction, or load shedding at the times (24) of the increased load requirement of the injection-molding machine (4).

2. Method according to claim 1, characterized in that the load level (28) for the activation of the control signal or control signals (22) or the change of the internal operating state or operating states (22) for the transmission or indication, respectively, of the presence of a load peak (21) in the injection-molding machine (4) or a work cell controller (26) is freely selectable, adjustable or automatically determined.

3. Method according to claim 1 or 2, characterized in that the injection-molding machine (4) continuously determines by calculation or ascertains by measurement the load level present during one or several operating cycles (18), in particular the operation between two successive closing operations of the mold (7), and stores it for subsequent analyses, in particular for determining the switching of the control signal or control signals (22) or the internal operating states (22).

4. Method according to claim 1 or 2, characterized in that an external work cell controller (26) continuously ascertains by measurement the load level present during one or several operating cycles (18) of the injection-molding machine (4), in particular the operation between two successive closing operations of the mold (7), and stores it for subsequent analyses, in particular for determining the switching of the control signal or control signals (22) or the internal operating states (22).

5. Method according to any one of the preceding claims, characterized in that the injection-molding machine (4) or an external work cell controller (26) can also send or indicate, respectively, the control signal or control signals (22) or internal operating states (22) with increased load requirement in advance, so that the independent production resources (2) can prepare corresponding actions for load control.

6. Method according to any one of the preceding claims, characterized in that the stand-alone production resources (2) are also designed to be self-learning and, preferably after tracking the behavior of the control signal or control signals (26) or the internal operating states (26) at least once in an operating cycle (18) of the injection-molding machine (4), can anticipate the occurrence of a load peak (21) in the injection-molding machine (4) and automatically carry out a load control.

7. Method according to any one of the preceding claims, characterized in that, in the case of automatic determination of the switching points of the control signal or control signals (22) or of the internal operating states (22) as a function of the load level (27) by the injection-molding machine (4) or an external work cell controller (26), the cumulative presence of the control signal or signals (22) or of the internal operating states (22) for load peaks (21) does not exceed the time of approximately 15% to 25% of a total cycle (18) of the injection-molding machine (4).

8. Method according to any one of the preceding claims, characterized in that the injection-molding machine (4) reports the difference between the maximum load peak (21) in an operating cycle (18) and the currently calculated or measured load or another measure and which directly or indirectly indicates the currently unneeded load requirement to a work cell controller (26).

9. Method according to any one of the preceding claims, characterized in that an external work cell controller (26) determines the difference between the maximum load peak (21) in an operating cycle (18) of the injection-molding machine (4) and the currently measured load of the injection-molding machine (4) and uses this to form the currently unneeded load requirement of the injection-molding machine (4).

10. Method according to any one of the preceding claims, characterized in that an external work cell controller (26) transmits the control signal or control signals (29) to the independent production resources (2) at different times, depending on the load consumption of the respectively active production resource (2), so that the total load of the production resources (2) does not exceed the load requirement not needed by the injection-molding machine (4).

11. Plastics processing plant comprising at least an injection-molding machine (4) and at least one stand-alone production resource operated with its own control system (2), such as a temperature control unit (13a), hot runner system, cooling unit (13b), flow controller (14), granule dryer (12), mold dryer, metering device (11), robot (5), automation systems, etc., wherein the injection-molding machine (4) is connected via an electrical line (27) or data line (27) to the at least one independent production resource (2) directly or indirectly via an external work cell controller (26), whereby the injection-molding machine (4) is designed for carrying out the method according to any one of claims 1 to 10.