Method and device for visualizing or evaluating a process state

Abstract

A method for evaluating and/or visualizing a process state of a production system, which contains at least one cyclically operating shaping machine, includes: continuously or at discrete times, determining the value of a plurality of selected process variables, and comparing the current value of each selected process variable and or a variable derived therefrom with one or more reference values by means a computing unit, and determining a deviation or a rate of change. Each selected process variable is assigned to at least one logical group by the computing unit; at least two different logical groups are provided; and for each logical group, a state of the logical group is evaluated by the computing unit based on the process variables assigned to the logical group and/or is visualized by a display device.

Claims

1. A method of evaluating and visualizing a process state of a production installation which contains at least one cyclically operating shaping machine, wherein continuously or in time-discrete relationship the value of a plurality of selected process variables is ascertained and the respective current value of each selected process variable or a variable derived therefrom is compared to one or more reference values by means of a computing unit and a deviation or a rate of change is determined, wherein each selected process variable is associated with at least one logical group by the computing unit, wherein there are provided at least two different logical groups, and logical groups are arranged in at least two hierarchy levels in such a way that at least one logical group of a lower hierarchy level is associated with another logical group of a higher hierarchy level, and for each logical group a state of the logical group is evaluated by the computing unit on the basis of the process variables associated with said logical group and is visualized by means of a display device.

2. The method according to claim 1, wherein an actual value, a target value, a key figure, a measurement value configuration, a variable calculated from a plurality of preceding values or an operating state is used as at least one selected process variable.

3. The method according to claim 1, wherein in determining the deviation or the change the computing unit takes account of whether there was a change caused by an operator, a process controller, a process optimisation system or by external influences.

4. The method according to claim 1, wherein at least one reference value is selected from the following list: one or more time-preceding value or values of the selected process variable, for example a value which directly preceded in respect of time of the selected process variable or a drift or scatter, a value of the selected process variable, stored by the operator at a given time, a value calculated from a number of process variables, a target value for the selected process variable, an ideal value, determined by an expert system, for the selected process variable, and a variable calculated from the current value of the selected process variable and/or one or more preceding values in respect of time of a process variable.

5. The method according to claim 1, wherein time-discrete ascertainment of the values of the plurality of selected process variables and/or determination of the deviation or rate of change is effected in one of the following ways: for a succession of production processes, upon the occurrence of a predefined event, and at predetermined time intervals.

6. The method according to claim 1, wherein the logical groups are formed in accordance with at least one of the criteria in the following list: installation region or components of the production installation, procedural step or state of a production process, properties of a moulding material being processed by the shaping machine, properties of a shaped part produced by the shaping machine, possible disturbances or errors in the production process, the existence of a desired state, productivity and economic efficiency, and environmental conditions.

7. The method according to claim 1, wherein: in a first hierarchy level, the logical groups are selected in relation to process steps in the production cycle, in a second hierarchy level lower that the first hierarchy level, the logical groups are selected in accordance with function units of the production installation, and in a third hierarchy level lower than the second hierarchy level, the logical groups are selected in accordance with physical parameters.

8. The method according to claim 1, wherein the logical groups of a hierarchy level are selected so that a screen page which can be visualized by means of the display device is associated with each logical group.

9. The method according to claim 1, wherein at least two observation levels are used, wherein one observation level represents a status of the process state of the production process and/or the production installation.

10. The method according to claim 9, wherein determination and/or display of the deviation or rate of change is effected along observation levels in such a way that determination and/or display of the deviation or rate of change of a next level is effected only when a previous observation level was found to be in order.

11. The method according to claim 1, wherein instructions are given to an operator for process optimisation or troubleshooting.

12. The method according to claim 1, wherein process optimisation or troubleshooting is carried out automatically by target values of the production process or the production installation being automatically altered and/or production being interrupted and/or spare part orders being triggered and/or customer services being notified.

13. The method according to claim 1, wherein evaluation and/or visualization of process alterations of a last cycle of the production process is effected in relation to one or more preceding cycles of the production process and/or in relation to a set of process variables stored at a user-defined time.

14. The method according to claim 1, wherein in addition to the visualization of process alterations a change in target value effected or an installation stoppage due to a change in operating mode is visualized.

15. The method according to claim 1, wherein only those logical groups or parameters are displayed, which have experienced an alteration in an observation period which is or can be set.

16. A non-transitory computer readable recording medium having stored thereon a computer program product comprising commands which in execution of the program by a computing unit cause it to carry out the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a chart illustrating determining and visualizing a change in a value of a process variable relative to the recent past;

(2) FIG. 2 is a chart illustrating determining and visualizing the deviation from a reference value;

(3) FIG. 3 is a chart illustrating use of knowledge of an expert system;

(4) FIGS. 4 and 5 are charts illustrating information filtering with observation levels;

(5) FIG. 6 is a chart illustrating a traffic light representation of process changes of a further embodiment;

(6) FIG. 7 is a chart illustrating a target disc representation of process changes of a further embodiment;

(7) FIGS. 8a and 8b are charts illustrating progress representation without curves;

(8) FIG. 9 is a chart showing a progress representation in relation to FIG. 8a; and

(9) FIG. 10 is a schematic diagram showing a production installation including a shaping machine.

DETAILED DESCRIPTION OF THE INVENTION

(10) First embodiment of the invention (FIG. 1)—determining and visualizing the change in the value of a process variable relative to the more recent past:

(11) The shaping machine is in the form of a plastic injection moulding machine. The description hereinafter, however, equally applies to other forms of shaping machines.

(12) The visualization program is of a hierarchical structure. The highest hierarchy level contains the logical group ‘process stability’. Provided on an underneath hierarchy level for evaluation of process stability are the logical groups ‘machine’, ‘granulate’, ‘melt’, ‘filling’, ‘tool’ and ‘shaped part’. Associated with each logical group of that upper hierarchy level on the next lower hierarchy level is at least one other logical group. For example here the logical group ‘tool’ includes the subgroups ‘heatings’, ‘temperature control’, ‘movements’ and ‘demoulding’.

(13) Associated with the logical group ‘temperature control’ is inter alia the key figure Delta_T_1. The value describes the temperature difference between the flow and the return of a temperature control medium passage of a tool. That process variable is measured in each working cycle (cycle No). A gradient is calculated from the comparison of the respectively current value with the preceding values. If the gradient exceeds a reference value in the form of a stored limit value then that is evaluated as instability and the logical group ‘temperature control’ is provided with a warning symbol (here shown by way of example as a call sign). As the logical group ‘temperature control’ is a subgroup of the higher logical group ‘tool’ that higher logical group also has the warning call sign symbol. The uppermost hierarchy level here contains the logical group ‘process stability’, that is now also marked with a call sign. Those logical groups which by virtue of the process variables associated therewith were found to be in order are marked with a tick symbol.

(14) In that way, variations can be evaluated in comparison with the fairly recent past like, for example, drifts, abrupt changes or increasing scatter effects.

(15) In the illustrated embodiment, in addition to the illustrated symbols, ticks and call signs there can also be colour codings, namely the colour green in connection with the tick and the colour red in connection with the call sign. The colour codings could also be provided alternatively to identification with symbols. Alternatively, it would be possible to provide only symbols, pure text indications or symbols combined with text indications (optionally with additional colour coding). Those statements apply generally to the invention.

(16) Second embodiment of the invention (FIG. 2)—determining and visualizing the deviation from a reference value:

(17) The shaping machine is in the form of a plastic injection moulding machine. The description hereinafter however equally applies to other forms of shaping machines.

(18) In this embodiment, comparison is effected with a reference state established by the operator. Here the media flows have changed in two temperature control circuits.

(19) Third embodiments of the invention (FIG. 3)—use of knowledge of an expert system:

(20) The shaping machine is in the form of a plastic injection moulding machine. The description hereinafter however equally applies to other forms of shaping machines.

(21) In this embodiment, the process variable ‘mass cushion’ (=foremost screw position during injection and holding pressure) is compared to a minimum value stored in the form of knowledge of an expert system, as a reference value, and is graded as being too slight.

(22) Fourth embodiment of the invention (FIGS. 4 and 5)—information filtering with observation levels:

(23) The shaping machine is in the form of a plastic injection moulding machine. The description hereinafter however equally applies to other forms of shaping machines.

(24) FIG. 4 plots from left to right logical groups (‘machine’, ‘granulate’, ‘melt’, ‘filling’, ‘tool’ and ‘shaped part’) of a given hierarchy level, with which certain target values, actual values, state variables and key figures are associated. Shown in an upward direction are observation levels which are here evaluated in succession (upwardly) and evaluate and visualize various states of the production process or the production installation which can be of interest to an operator.

(25) FIG. 4 shows by way of example a situation prior to production start of a plastic injection moulding machine. The heatings are switched on, the target temperatures, however, are not yet reached. The temperature actual values of machine (cylinder heating) and tool are moving in the direction of the target values. It is only when the target values are reached that the next step in evaluation is effected—stability of the associated process variables. The logical groups ‘granulate’, ‘melt’, ‘filling’ and ‘shaped part’ can only be evaluated in that state insofar as the target values were not changed in relation to a reference.

(26) FIG. 5 shows a possible state during production (therefore at a later time than in FIG. 4). One or more process variables which are suitable for evaluating the logical group ‘melt’ are moving away from that value which was established at the time of fixing the corresponding reference value.

(27) A process variable which is suitable for evaluating the logical group ‘filling’ has a higher degree of scatter compared to the reference. A process variable which is suitable for evaluating the quality of the logical group ‘shaped part’ drifts in the direction of the reference value stored in the referencing operation.

(28) The shaping machine in the fifth embodiment of the invention (FIGS. 6-9) is in the form of a plastic injection moulding machine. The description hereinafter equally applies however for other forms of shaping machines.

(29) The embodiment in FIG. 6 provides a traffic light representation of process changes in the last cycle in relation to immediately preceding relational values (left-hand representation) and in relation to relational values stored at a user-defined time (right-hand representation). Six logical groups are evaluated and visualized. Grouping is effected in accordance with process steps (here for example ‘dry and convey’, ‘melt plastic’, ‘fill mould’, ‘cool part’, ‘mould and removal’, ‘quality inspection’). By way of the buttons ‘show progress’ it is possible to view a variation in respect of time (thus as shown in FIG. 8a, a change is made to the corresponding page). In the present example there are changes in relation to the solid circles (for example yellow in colour). Representation options for visualization can be selected by way of the button ‘settings’. It is possible for example to select how many preceding cycles in terms of evaluation and visualization are to be adopted as the basis. By way of the button ‘signalling’ the user can select signalling (alarm message, alarm lamp, SMS, e-mail and so forth), for the situation where a change in process is soon to be observed. By way of the button ‘stored values’ those relational values which form the basis for the comparison shown on the right-hand side can be input, altered or deleted. By way of the boxes shown in the top line of the representation it is possible to make a selection in respect of the visualization option by setting a tick (in the present case both visualization options have been selected). FIG. 6 visualizes that in this example there is a deviation from the preceding values (only) in relation to the logical group ‘melt plastic’. More precise analysis is available to the user by choosing the button ‘show progress’, by means of which he changes to the page shown in FIG. 8a.

(30) In the FIG. 7 embodiment a target disc representation of process changes in the last cycle of the production process in relation to preceding and stored values was selected. Four logical groups are visualized, a quadrant in the illustrated co-ordinate cross being attributed to each logical group.

(31) This example involves optional joint representation of the deviation from preceding values and values stored as a reference, in the form described hereinafter:

(32) The standardized removal of parameters from their associated stored value is symbolised in the target disc by the spacing from the centre point.

(33) Parameters which deviate from the stored relational value are more or less away from the centre point depending on the respective extent of their deviation. If they do not change at the moment they are visualized as points (by way of example two such points are shown in the view). If the parameters change at the moment they are not visualized as points but as arrows, more specifically in such a way that the direction of the change relative to the stored relational value is visualized by the direction of the arrow relative to the centre point (four such arrows are to be seen by way of example in the representation).

(34) The comparison with the preceding values is therefore so effected that parameters which are visualized as points do not exhibit any deviation from that value which they had in the preceding cycle or cycles.

(35) A ‘tolerance’ which is preset at the factory and/or can be predetermined establishes from what deviation from the stored relational value visualization is effected.

(36) A representation of aggregation and the extent of the deviation is effected in the form described hereinafter:

(37) Parameters which are remote from the stored reference value less than a permissible tolerance are in the innermost circle in the target disc. If they are in the target region and do not change they are not represented for the sake of clarity. Each further circular ring symbolises a spacing around the predetermined tolerance. If a parameter is in the outer white ring it is therefore 3-4 times outside the tolerance.

(38) Instead of representing each parameter individually this example provides for implementing aggregation in the manner described hereinafter. In the process step ‘fill mould’ for example 5 parameters are 3-4 times outside the tolerance. Those values are stable and therefore do not change at the moment and are therefore visualized as points. A further three parameters in that segment of the circle are further away from their stored relational value and are therefore visualized as arrows in a direction away from the centre point. Naturally any other kind of grouping is possible.

(39) By pressing one of the buttons ‘show progress’ that gives a progress representation over a defined period of time or a defined number of cycles.

(40) In this embodiment it is only possible to select the comparison with the preceding values. In such a case all parameters are visualized as points.

(41) The embodiment of FIG. 8a involves progress representation without curves: the configuration of the process change in relation to preceding values is represented over the last 40 cycles (naturally another number could also be set). Results which can concern a number of logical groups are represented as symbols in the header (on the common x-axis).

(42) It can be seen that for example between cycles No 18539 and No 18549 a change in mode of operation took place (indicated by a star). Between cycles No 18559 and No 18569 the user performed a change in target value (here indicated for example by a smiley).

(43) Hierarchical logical grouping is effected according to: process steps-function units-physical variable. By way of example the hierarchy is shown for the group ‘melt plastic’ (as a process step), with the subgroups ‘cylinder heating’ and ‘metering’ (as function units) and the respective further subgroups ‘temperature’ and ‘power’ or ‘time’ and ‘moment’ (as a physical variable). It can be seen that the change in target value shown in the header was effected in relation to a temperature of the cylinder heating. The hatched regions in ‘temperature’ and ‘power’ show an alarm situation which occurred by virtue of the alteration made. The same applies in regard to the right regions in the subgroups ‘time’ and ‘moment’ of the subgroup ‘metering’ while the left hatched region in the subgroup ‘time’ is a consequence of the change in the mode of operation.

(44) FIG. 8b explains the significance of the symbols which can be seen in FIG. 8a.

(45) An automatic preselection can be provided:

(46) If the user changes to that page then only those logical groups or parameters are displayed, which have experienced an alteration in the set observation period (here 40 cycles). Automatic preselection of those items of information which are relevant at the moment is therefore effected. By activating the function ‘display all parameters’ the user can also view the parameters which are stable in the observation period.

(47) A process alteration is shown in the example. In this case the parameters are compared in each cycle to their most recent past. If for example a temperature changes from 220° C. to 230° C. that transitional period is characterized until the new stable temperature is reached.

(48) The illustration of the process alteration in relation to stored relational values would appear similarly. The difference however is that the marking of the time span ends only when the state at the time of the user-defined storage is restored.

(49) By way of the button ‘limits’ it is possible to set acceptable tolerances or (if they are predefined at the factory) alter them.

(50) The embodiment of FIG. 9 shows a progress representation in relation to FIG. 8a with extended curve region of the physical variable ‘temperature’:

(51) This involves a representation of the curve configuration with tolerances shown in broken line (limits). The tolerances are predefined at the factory but can be altered by the user. The establishment of tolerances can be effected for individual parameters or for parameter types (for example all temperatures, all cylinder temperatures, and so forth).

(52) It is possible to provide a parameter selection in the form such that a set of parameters to be monitored is predefined at the factory, but the monitoring of each parameter can be deactivated by the user.

(53) The measures shown in FIGS. 6 to 9 in relation to an embodiment of the invention can also be provided individually or in any combination.

(54) In relation to the above-discussed embodiments of a visualization apparatus it is true to say that they equally apply in relation to an evaluation apparatus if visualization is not considered to be obligatory.

(55) FIG. 10 diagrammatically shows a production installation 1 including a shaping machine 2 and a handling apparatus 3. A computing unit 4 and a storage medium 6 are connected to a display device 5 by way of a data connection 7 to provide the evaluation and/or visualization apparatus.

(56) The display device 5 can be in the form of a screen of a machine control means of the shaping machine 2 and/or in the form of a web portal and/or in the form of a visualization apparatus which can be carried or worn on a body (for example a handheld device like a tablet or VR glasses).

(57) Otherwise than as illustrated, the computing unit 4 and the storage medium 6 could naturally also be a part of the shaping machine 2, for example a part of the machine control means.

(58) An evaluation program is stored in the storage medium 6, wherein various logical groups can be imaged by the evaluation program and each selected process variable is associated with at least one of the logical groups and for each logical group a state of the logical group can be evaluated on the basis of the process variables associated with that logical group.

(59) In addition a visualization program is stored in the storage medium 6, wherein various logical groups can be visualized by the visualization program and each selected process variable is associated with at least one of the logical groups and for each logical group a state of the logical group can be visualized by the display device 5 on the basis of the process variables associated with that logical group.

LIST OF REFERENCES AND TERMINOLOGY USED

(60) 1 production installation 2 shaping machine 3 handling apparatus 4 computing unit 5 display device 6 storage medium 7 data connection Measurement value: value delivered by a sensor or a value determined on the basis of the signals delivered by the sensor, of a physical variable of the production installation, one of its components or the process material Process variable: variable ascertained from a measurement value or values, can be represented in the form of one or more key figures Key figure variable ascertained from a process variable like for example properties of measurement curves; time at which measurement variables assume given values, and so forth Target value setting value for the production installation Reference value value which is used for a comparison with a process variable Reference state combination of reference values at a given time which characterises the state of the production installation or parts thereof at that time Relational value special form of a reference value, namely process variable stored at a user-defined time for comparison with one or more process variables Tolerance value (for example in the form of a band around a curve) which specifies from what deviation visualization and/or evaluation is effected.