AT512781B1 - Method for operating energy consumers of an injection molding machine - Google Patents

Abstract

Method for operating energy consumers (1) of an injection molding machine (2), each energy consumer (1) is allocated a partial energy consumption (T), for all energy consumers (1) together a maximum energy consumption (Emax) is set, to avoid exceeding the specified Energy consumption (Emax) at a first time (t1) at least one energy consumer (1) no energy (E) is allocated, and each energy consumer (1) at the first time (t1) has a priority value (P) for energy allocation, wherein at a later second time (t2) the priority value (P) of each energy consumer (1) is updated in dependence on the energy (E) allocated at the first time (t1), the energy allocation to each energy consumer (1) being dependent on the updated priority value (P) he follows.

Description

Austrian Patent Office AT 512 781 B1 2013-11-15

The invention relates to a method for operating energy consumers of an injection molding machine, each energy consumer is allocated a share of energy consumption, for all energy consumers together a maximum energy consumption is set, to avoid exceeding the specified maximum energy consumption at a first time at least one energy consumer no energy is assigned to each energy consumer at the first time a priority value for energy allocation or has a priority value.

In such known methods or injection molding is about the limitation of the power consumption of an injection molding machine or an entire injection molding. Each energy consumer (heating, drives, etc.) can limit the energy supply. A maximum energy consumption (total limit) prevents the main connection from being exceeded.

A method for operating an injection molding machine is disclosed in WO 2011/157564. In order to obtain an increased energy efficiency in injection molding machines, a power profile for a drive is specified, based on performance requirements that operating combination of drives is determined from the performance data that results in the performance profile. Thus, a certain performance profile of the sum of the individual drives must not be exceeded.

From DE 10 2007 059 781 it is clear to keep the maximum connected load of facilities as low as possible. Feedback via feedback cables results in a 30 to 50% reduction in the total connected load during the production process. It is extended by temporal displacement of the control of the heating control circuits only the heating phase of the individual control loops. The sum of the electric power supplied to the heating control circuits is thus always lower than a power setpoint. In this document, it is only about the control of heating control circuits and not other energy consumers such. Engines.

DE 196 51 484 A1 shows a method for optimizing the power consumption of a composite of electrically heated or cooled consumers of a plant in the plastics processing industry. A phase-shifted control regulates the power consumption of the consumers and the consumer network.

EP 0 193 485 B1 shows a non-generic power supply system for a vehicle in which priority is given to loads in such a way that the loads are switched on or off in a predetermined sequence. A high load can be circumvented by the fact that successive engagements of loads of relatively higher priority in favor of turning on loads of relatively low priority are not performed. The priority values remain unchanged, they are simply ignored. The priority itself does not affect whether a load receives power.

US 4,031,406 shows an electrical balancing control system for multiple consumers. There is no counter per consumer and thus no possibility for continuous recording of a priority. Rather, a sequence for the power supply of the individual consumers is given circuit-wise via a fixed wiring.

The generic US 7,568,905 B2 has as a goal to reduce energy costs as much as possible. As soon as a total consumption exceeds a certain limit value, at least one component is at least partially no longer supplied with energy ("de-energized"). Through this "de-energizing" the peak is reduced to a lower peak. Furthermore, it is stated that the "de-energizing " of components based on a priority, with the "least significant " Component does not receive energy.

A disadvantage of the latter document, as well as in the previous writings, is that only after a certain time or until after final supply of an important component, a 1/10 Austrian Patent Office AT 512 781 B1 2013-11-15

Component with lower priority is re-energized. So it may take a relatively long time for an "unimportant " Energy consumer is re-energized. Above all, it can happen that an important component prevents the energy supply of almost all other energy consumers for a long time.

The object of the present invention is therefore to provide a comparison with the prior art improved method or an improved injection molding machine. In particular, an energy-efficient and at the same time "fair" Supply of individual energy consumers with energy can be guaranteed.

This is achieved by a method having the features of claim 1. According to the invention, it is accordingly provided that, at a later, second point in time, the priority value of each energy consumer is updated as a function of the energy allocated to the respective energy consumer at the first time, wherein the energy allocation to each energy consumer takes place as a function of the updated priority value. Thus, there is no absolute predetermined priority value for a particular energy consumer, but this priority value is constantly or regularly changed. The energy supply is therefore no longer dependent only on the time or external requirements, but constantly changes depending on the last time or the last run to the respective energy consumer allocated energy.

In principle, the energy consumer can either be assigned the priority value by a control or regulation unit or the energy consumer himself reports his (updated) priority value to the control or regulation unit or to a higher-level control module of the control or regulation unit.

According to a preferred embodiment of the present invention can be provided that at the second time each energy consumer, the energy was allocated at the first time, a lower priority value is assigned or the energy consumer is reported a lower priority value, while each energy consumer, the no energy has been allocated at the first time, a higher priority value is allocated, or a higher priority value is reported by the energy consumer himself. This ensures that the "importance" each already supplied energy consumer is reduced, while the "importance" of a non-powered energy consumer.

In order to enable adaptation to the various production needs, it is preferably provided that the priority values are variable as a function of a phase of an injection molding cycle. Thus, upon reaching a certain phase of an injection molding cycle, the priority values of all energy consumers can be set to a certain absolute value, and then, starting from this value, priority control again takes place. It can also be provided here that the maximum energy consumption changes or that the maximum energy consumption is increased or decreased at least for certain partial areas.

In principle, the times at which a recalculation of the energy supply takes place can be any time apart (for example a few seconds). In order to avoid too long a non-supply of an energy consumer, it is therefore provided that between the first time and the second time between 1 and 800 milliseconds, preferably between 3 and 20 milliseconds, more preferably 6 milliseconds lie. Thus, a recalculation is preferably carried out every six milliseconds, or the priority values of the individual energy consumers are updated every six milliseconds. The output and repriori-tion can also take place in a further time frame (eg every 500 milliseconds). This can be set in the controller as a parameter.

Further details and advantages of the present invention will be explained in more detail below with reference to the description of the figures with reference to the embodiments illustrated in the drawings. FIG. 1 shows schematically an injection molding system, FIG. 2 shows a flow chart of a priority update, FIG. 3 shows schematically a control module, [0020] FIG 4 and 5 schematically show a plurality of control components arranged in cascade fashion, FIG. 6 shows a diagram of the limitation of the maximum energy consumption of individual energy consumers, and [0022] FIG. 7 shows the displacement of the energy supply of individual consumers during a group cycle time.

Fig. 1 shows a factory building 18 with an injection molding system arranged therein consisting of at least two injection molding machines 2. From an external (or internal) energy source 3, energy E (in particular electrical current) is conducted into the factory floor 18. The introduced energy E is distributed to the individual consumers 1 via the control unit 4. Accordingly, each energy consumer 1 receives a partial energy consumption T via the control or regulation unit 4 from the energy source 3. The priority values P, the maximum energy consumption M and the partial energy consumption T of the individual energy consumers 1 are stored in the memory 5 of the control unit 4.

The injection molding machine 2 consists of a frame 11 arranged on the fixed platen 13 and a movable platen 9. This movable mold clamping plate 9 is movable via a toggle mechanism 8, said toggle mechanism 8 via a driven by the drive unit 6 spindle. 7 is movable. This drive unit 6, which forms an energy consumer 1, is attached to the end plate 10. On the movable platen 9 as well as on the fixed platen 13 each mold halves of a tool 12 are arranged. The heating elements arranged in or on this tool 12 form a further energy consumer 1. In addition, the injection molding machine 2 has a plasticizing unit, which consists of a plasticizing cylinder 16, a plasticizing screw 15 and a drive unit 14. In this case, the drive unit 14 forms, like the heating device arranged in or on the plasticizing cylinder 16, in each case one energy consumer. [0025] 1. Another energy consumer 1 forms the handling robot 17, by means of which injection-molded parts can be removed from the tool 12. The injection molding machine 2 can in principle also be designed as a two-plate machine.

1, the control or regulating unit of the first injection molding machine 2 forms a master processing unit for the other injection molding machines 2 in the factory floor 18. Preferably, however, is an unrepresented, higher-level total computer for the entire factory floor 18 is provided with the individual, each injection molding machine 2 associated control or regulating units 4 communicates.

2 shows the most important component of the control or regulation unit 4, namely the control module 19. This control module 19 receives from a higher-level unit (eg from the memory 5 or by input of an operator) a power limit in the form of a maximum energy consumption Emax of 60 kW. The attached consumers 1 (in this case the heater for the tool 12, the heater for the plasticizing cylinder 16 and the drive unit 14) require a total of 80 kW. The priority control of the control module 19 now has the task of distributing the energy E so that no exceeding of the maximum energy consumption Emax occurs. Before the division takes place, the current priority value P is polled at time L of each energy consumer 1. According to the example, all energy consumers 1 have the same priority P in the first pass. Such a pass corresponds to the cycle time of the system, which is usually 6 ms. Since all energy consumers 1 have the same priority value P, the energy consumers 1 are sequentially allocated the energy E until the maximum energy consumption Emax of 60 kW is reached. Therefore, only the first two energy consumers 1 are supplied with energy E at the time ti.

Subsequently, at the time t2, the priority values P of each energy consumer are updated as a function of the energy E allocated at the first time L. Thus, the priority value P of the heating of the tool 12 is set to a lower priority value P-set. The same applies to the energy consumer 1 supplied at the time ti with energy E (heating device for plasticizing cylinder 16). On the other hand, the drive unit 14 is assigned a higher priority value P + or registers with a higher priority value P +. First, therefore, at time t2, the drive unit 14 is assigned the power E of 40 kW due to the highest priority P. Since the two first energy consumers 1 again have the same priority P, only the first energy consumer 1 energy E is assigned by 20 kW, while the second energy consumer 2 due to the already reached maximum energy consumption Emax no energy E is assigned.

After this second pass, a new priority value calculation is performed at time t3. Accordingly, the heater for the tool 12 is again assigned a lower priority value P-, whereby this energy consumer 1 now has the lowest priority P and no energy E assigned. The heating device of the plasticizing cylinder 2 as the second energy consumer 1 is assigned a higher priority value P + at time t3, while the priority value P of the drive unit 14 is reduced. Nevertheless, due to the still high priority P, this drive unit 14 is supplied with energy E of 40 kW. At time t4, in turn, the priority value P of each consumer 1 is updated as a function of the energy E allocated at the previous time t3.

There are basically two variants for the provision of the individual services. On the one hand, the services or the energy consumption of the individual energy consumers 1 can be measured, or the individual services are provided by inputs by a user (pure software solution). To capture the actual performance of the entire periphery (e.g., temperature controllers, etc.), the individual outputs are subtracted from the total power of the machine connection. A handling robot 17 is seen as periphery in this context.

FIG. 3 shows a control module 19 which can divide the energy E supplied to it independently of the attached energy consumer 1. It is irrelevant who is connected as an energy consumer 1 or how many energy consumers 1 are connected. By default, the control module 19 receives a limit of energy supplied to it. The control module 19 sends a power requirement L, a priority P, and the partial energy consumption T actually obtained at the last time t. Depending on the design, the control module 19 can also transmit the higher-ranking point receives these parameters L, P and T. Just as the control module 19 receives limited energy Emax from a superordinate point, as with the arrows underneath the control module 19, limited energy Emax is passed on to the energy consumer 1 or to further control components 19.

In Fig. 4 is therefore apparent that a higher-level power module 19 corresponds to an injection molding machine 2. In a subordinate hierarchical level, further control components 19 are shown, which correspond to the heating device for the tool 12, the heating device for the plasticizing cylinder 16 or the drive units 6 and 14 or the drive unit for the handling robot 17.

In Fig. 5 is again superordinate another control module 19 shown, which corresponds to the factory floor 18. Due to the cascading or linking possibilities of the individual control modules 19, these can be nested as often as desired and thus also see other control modules 19 as energy consumers 1. The individual control modules 19 detect the required power (power requirement L), regardless of whether heater, drive unit or other control module 19. The, preferably stored in the memory 5, power requirement L is compared with the current priority P and the last allocated partial energy consumption T and then according to newly calculated priority P- or P + reassigned, lowered or completely interrupted. Depending on the energy consumption 1, it is not necessary - as shown in FIG. 2 - to completely interrupt the energy supply to a single energy consumer 1 if this would exceed the maximum energy consumption Emax. Rather, it could also be provided that the energy input of a single energy consumer 1 is only reduced, so that the maximum energy consumption Emax is not exceeded.

FIG. 6 shows in a diagram the maximum energy consumption Emax along a time line t. The maximum energy consumption Emax is composed of the limit E (12 + 16) required for the heaters for the tool 12 and the plasticizing cylinder 16 and the limit E (14 + 16 + 17) for the drive units 14 and 6 or the handling robot 17. In the first phase PH (heating phase) is mainly a limitation of the drives while the heating is almost maximum. In contrast, in the second phase PH (production phase), an increase in the energy supply, especially to the drive units 14,16 and 17.

In Fig. 7 shows how the present invention optimum utilization of energy consumption without exceeding a maximum energy consumption Emax is possible. For this purpose, individual zones 1 to 4 of a heating device are shown as an example, which require between 3 and 5 kW. Normally, each individual zone 1 would require a certain heating time and a certain cooling time, depending on the predetermined or stored cycle sequence. If each zone 1 to 4 additionally receives a priority P, optimally the maximum energy consumption Emax of 10 kW can never be exceeded. At the first cycle time (time ti) the zones 2 and 3 are supplied with energy E due to their highest priority P. Within a group cycle time, therefore, ideally all zones 1 to 4 are supplied, at least in the short term, with energy E. The heating of zone 4 is no longer in a continuous heating phase, but divided into several group cycle times. Also, the heating of the zone 1 is no longer at regular intervals, but depending on the given priority P. At each start of a new group clock time, the individual priorities P can be set back to the output priority.

As regards the priorities P, it is generally stated that these are preferably indicated as absolute values. Of course, these priorities P can also be given as percentages, for example of the maximum energy consumption Emax, whereby the percentage is increased or decreased by 2% per run, for example. The updated priority values P are generally calculated within the control unit 4. This calculation can be carried out in particular by a subordinate or a higher-level control module.

The advantages of the present invention are thus in a power specification for any number of energy consumers 1. In addition, the individual energy consumers 1 for the control or regulating unit 4 or for its control modules 19 may not be known. The number of connectable energy consumers 1 is virtually endless. In addition, nesting or cascading of the individual control modules 19 is possible. Furthermore, automation of the energy limit is integrated in each control module 19, whereby an independent distribution of the energy E provided by the energy source 3 is possible. 5.10

Claims (4)

Austrian Patent Office AT 512 781 B1 2013-11-15 Claims 1. A method for operating energy consumers (1) of an injection molding machine (2), wherein • each energy consumer (1) is allocated a partial energy consumption (T), • for all energy consumers (1) together, a maximum energy consumption (Emax) is set, to avoid exceeding the specified maximum energy consumption (Emax) at a first time (ti) at least one energy consumer (1) no energy (E) is allocated, and • each energy consumer (1) to the first Time (ti) has a priority value (P) for energy allocation, characterized in that at a later, second time (t2), the priority value (P) of each energy consumer (1) in dependence on the first time (^) allocated energy (E) is updated, wherein the energy allocation to each energy consumer (1) in dependence on the updated priority value (P) takes place. 2. The method according to claim 1, characterized in that at the second time (t2) each energy consumer (1), which was allocated at the first time (t ^ energy (E), a lower priority value (P), while each energy consumer ( 1) to which no energy (E) has been allocated at the first time (t 1) has a higher priority value (P +). 3. The method according to claim 1 or 2, characterized in that the priority values (P) in response to a phase (PH) of an injection molding cycle, a group cycle time or the maximum energy consumption (Emax) are variable. 4. The method according to any one of claims 1 to 3, characterized in that between the first time (ti) and the second time (t2) between 3 and 20 milliseconds, preferably 6 milliseconds lie. 3 sheets of drawings 6/10