JP4022116B2 - Product discrimination apparatus and method for injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a product discrimination apparatus and method for an injection molding machine.
[0002]
[Prior art]
The injection molding machine includes a plurality of detectors in order to detect the operation state of each part, the state of the resin, and the like. The output (shot data) of these detectors is not only used to servo-control each part during injection molding, but also for determining molding conditions, checking operation during continuous injection molding, and determining product quality. Used.
[0003]
The molding conditions are determined by repeating injection molding, collecting shot data at that time, and changing the molding conditions. In order to complete the determination of the molding conditions in a short time, it is necessary to easily recognize how the influence of the change of the molding conditions appears in the shot data. Further, in order to realize stable continuous molding by an injection molding machine, it is necessary to easily confirm that shot data is within a predetermined range. In order to satisfy these requirements, the control device of the injection molding machine has a function for displaying shot data in a waveform (graph) on a display.
[0004]
The control device of the injection molding machine stores shot data and displays the shot data in a waveform on the display based on the setting or according to the input. At this time, by displaying the latest shot data, the previous or previous shot data, or the shot data at the time of good product molding superimposed, it is possible to determine the suitability of molding conditions for the latest shot data and to confirm the molding operation status at a glance. It becomes possible to do.
[0005]
When molding highly difficult products or when quality requirements are high, the suitability of molding conditions is judged based on more detailed information (information from more detectors with shorter detection cycles). Or checking the molding state. By using the waveform display, these determinations and confirmations can be made in a very short time.
[0006]
By the way, actual values such as cycle time, filling time, weighing time, cushion position, and weighing completion position (pre-filling position) are used to determine the quality of a product molded by an injection molding machine. Further, the maximum value and the minimum value in a predetermined section (time) with respect to the predetermined shot data are also used for determining the quality of the product.
[0007]
However, in the product discrimination method using the above evaluation items, the accuracy of pass / fail judgment may be poor. For example, when molding a relatively small product, the resin filling amount is small and the filling time is short (filling is performed at high speed) (in terms of controllability of the injection molding machine and the resolution related to time measurement and position detection). However, there is no significant change in shot data. Therefore, in such a case, the pass / fail judgment accuracy deteriorates.
[0008]
Therefore, to prevent deterioration of the quality determination accuracy as described above, as a method of performing high quality decision reliability, the resin pressure in the injection process of the resin pressure from the predetermined pressure P ₀ to reach a holding pressure switching pressure P _P A method for obtaining an integral value (time integration) has been proposed (Japanese Patent Laid-Open No. 4-173316).
[0009]
[Patent Document 1]
JP-A-4-173316
[Problems to be solved by the invention]
As described above, in the product discrimination method using the actual values such as cycle time, filling time, weighing time, cushion position and weighing completion position, and the maximum value and minimum value in a predetermined section (time) of certain shot data as evaluation items There is a problem that the accuracy of the pass / fail judgment is deteriorated depending on the type of product.
[0011]
Further, in the method of obtaining the integral value of the resin pressure in the injection process, there is a problem that the accuracy of the pass / fail judgment cannot always be improved because the integral section is fixed.
[0012]
SUMMARY OF THE INVENTION An object of the present invention is to provide an injection molding machine discriminating apparatus and a discriminating method capable of executing product quality judgment in an injection molding machine with high accuracy.
[0013]
[Means for Solving the Problems]
According to the present invention, in a product discriminating apparatus for an injection molding machine for discriminating the quality of a product molded by an injection molding machine, the display device, the setting device, and a control unit connected thereto are provided, control unit, the injection detection value of the injection pressure or the like from the detector provided in the molding machine in association with the time such as the detection data and to store, the detection data in accordance with the setting from the setting device While displaying on the display, and displaying the detected data such as the injection pressure on the display as a function of the time, etc. reception area designation for designating an arbitrary area of, calculated by integrating the integral value for the time such a detection value of the injection pressure or the like in the designated region, et al using the integral value obtained in the quality determination of the product Injection molding machine product discriminating device is obtained, which comprises using as the evaluation item that.
[0014]
Further, according to the present invention, in a product discrimination method for an injection molding machine for discriminating the quality of a product molded by an injection molding machine , a detection value such as an injection pressure from a detector provided in the injection molding machine is obtained. A graph is displayed on the display as a function of time, etc., and an arbitrary area is specified for the time on the graph displayed on the display using a setting device, and the detected value in the specified area is set to the time, etc. A product discriminating method for an injection molding machine is obtained, in which an integrated value obtained by integrating is obtained, and the obtained integrated value is adopted as an evaluation item for determining the quality of the product.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 shows a product discrimination device for an injection molding machine according to a first embodiment of the present invention. The product discriminating apparatus 10 according to the present embodiment is realized by a control device of the injection molding machine 20, and includes a setting device 11, a display device 12, and a control unit 13 connected thereto.
[0017]
The setting device 11 receives instructions for inputting parameters necessary for controlling the injection molding machine 20, operating the injection molding machine 20, and setting / changing information displayed on the display 12.
[0018]
The display 12 displays various information related to the injection molding machine under the control of the control unit 13.
[0019]
The control unit 13 controls each drive unit (not shown) of the injection molding machine 20 and causes the injection molding machine 20 to perform an injection molding operation. At this time, the control unit 13 receives detection outputs from various detectors (not shown) provided in the injection molding machine 20, and performs servo control of each drive unit, resin pressure control, temperature control, and the like. Do. The control unit 13 associates detection outputs from various detectors with time information as shot data (detection data), and stores the shot data in a built-in storage unit or an external storage device (not shown). Further, the control unit 13 causes the display unit 12 to display the generated shot data and / or the shot data stored in the storage unit based on the setting from the setting unit 11 or according to an instruction.
[0020]
Hereinafter, the operation of the product discrimination device 10 will be described in detail with reference to FIGS. 2 to 4 in addition to FIG. The operation of the injection molding machine 20 and its control are the same as in the prior art, and the description thereof is omitted.
[0021]
Each time the control unit 13 causes the injection molding machine 20 to perform an injection molding operation, the detection output from each detector is associated with time information as shot data and stored in a storage unit (not shown). At this time or later, by giving an instruction from the setting device 11, the obtained shot data can be stored as shot data at the time of good product molding.
[0022]
When an instruction is given from the setting device 11 to display a waveform (graph) on the display device 12, the control unit 13 causes the display device 12 to display a waveform display screen. The waveform display screen displayed on the display device 12 differs depending on the settings made in advance from the setting device 11 and subsequent change instructions, for example, as shown in FIG.
[0023]
The screen shown in FIG. 2 can simultaneously display eight graphs corresponding to the eight channels CH1 to CH8. As the graph to be displayed, for example, set values and detection values such as injection pressure, injection speed, screw position, nozzle internal pressure, internal pressure, injection torque, and mold clamping torque in the injection process (filling / holding process), There are set values and detection values such as back pressure, screw rotation torque, screw rotation speed, cylinder temperature, and resin temperature in the weighing process. Here, four graphs (corresponding to CH1 to CH4) representing changes in the injection speed set value and detection value in the injection process, and the injection pressure (holding pressure) set value and detection value over time are displayed.
[0024]
The graph of the waveform display screen displayed on the display device 12 usually displays the graph corresponding to the latest shot data. However, it is also possible to display a graph corresponding to previous shot data stored in the storage unit.
[0025]
When the screen shown in FIG. 2 is displayed on the display device 12, pressing any of the “channel” buttons 21 on the screen using the setting device 11 hides the graph corresponding to the channel. it can. If the same “channel” button 21 is pressed, the corresponding graph can be displayed again. Thereby, the Y-axis item of the graph to be displayed on the screen can be selected / changed.
[0026]
When the “cursor” button 22 on the screen is pressed using the setting device 11 to set the cursor display to “ON”, two cursors 32 and 33 are displayed below the waveform display area 31 as shown in FIG. Is done. In the waveform display area 31, two straight lines 34 and 35 corresponding to these two cursors and extending in the vertical direction in the figure are displayed. Further, the positions of the cursors 32 and 33 are numerically displayed in the cursor position display area 36 at the lower right of the screen. The two cursors 32 and 33 can be moved in the horizontal direction of the figure using the setting device 11. At this time, in accordance with the movement of the cursors 32 and 33, the two straight lines 34 and 35 displayed in the waveform display area 31 also move in the horizontal direction in the figure.
[0027]
When the “cursor” button 22 is pressed, the control unit 13 displays the cursors 32 and 33, the straight lines 34 and 35, and the cursor position on the display screen of the display 12 as described above. At the same time, the control unit 13 grasps the positional relationship between the straight lines 34 and 35 and the respective graphs, and obtains integral values of the sections divided by the two straight lines 34 and 35, respectively. In other words, the control unit 13 obtains the integral value of the region designated by the cursor for each graph. Then, the control unit 13 displays the obtained integral value in an area 37 on the display screen where the maximum value and minimum value of the graph are displayed (displayed as “Int”).
[0028]
In the example shown in FIG. 3, the cursors 32 and 33 designate sections in common for all graphs. However, the interval suitable for obtaining the integral value varies from graph to graph. In order to specify different sections for each graph using the cursors 32 and 33, as described above, the “channel” button 21 is pressed to display only one graph, and then the “cursor” button 22 is pressed to move the cursor 32. , 33 may be displayed.
[0029]
For example, in the case of a graph showing a change in injection pressure over time, a section suitable for obtaining the integral value is a section including a time point when the filling peak pressure is obtained. This is because before and after the time when the filling peak pressure is obtained, the difference is most likely to occur when compared with the graph at the time of good product molding. FIG. 4 shows an example of a case in which a section is designated with the cursors 41 and 42 so as to include a point in time when a peak pressure is obtained with respect to a graph showing a change in injection pressure over time.
[0030]
In FIG. 4, a graph for obtaining the integral value and a graph for good product molding are displayed in an overlapping manner. As is clear from FIG. 4, there is a relatively large difference between these two graphs before and after the point when the filling peak pressure is obtained. The positions of the cursors 41 and 42 are determined so as to include an area where a relatively large difference is seen between these graphs. As shown in FIG. 4, when the cursor is displayed in a state where the graphs at the time of good product molding are displayed in an overlapping manner, the maximum value, minimum value, integral value, etc. at the time of good product molding are displayed on the right side of the screen. Thereby, quantitative comparison with other waveform data becomes possible.
[0031]
Further, as a section for obtaining the integral value, a section having a large load on each part of the injection molding machine can be designated. For example, in an injection molding machine, a screw mechanism such as a ball screw is used as a motion direction conversion mechanism that converts motor rotation into linear motion, and the filling peak pressure during the injection process has a significant effect on the life of this screw mechanism. give. Moreover, the injection torque and the pressure in the pressure holding process affect the temperature of the motor. Therefore, by selecting an arbitrary section that most affects the life of the screw mechanism and the motor temperature, and calculating the waveform of the section, such as integration, the life of the screw mechanism can be predicted and the load status of the motor can be estimated. I can know. As a result, abnormalities in the molding machine can be predicted in advance, and parts can be replaced and maintained, or molding conditions can be changed and production processes can be changed without affecting the current production process. It becomes possible. Here, in order to predict the occurrence of abnormalities in the molding machine, calculation is not performed for all sections of a certain process (for example, injection process), so the occurrence of abnormalities in the molding machine is predicted without imposing a heavy load on the control unit. can do.
[0032]
As described above, the control unit 13 performs screen display control on the display unit 12 and calculation for obtaining an integral value, and also performs product discrimination monitoring. That is, the control unit 13 collects data related to product discrimination items used for product discrimination.
[0033]
When the waveform display on the display unit 12 is finished, a product discrimination monitoring screen is displayed there. The product discrimination monitoring screen is, for example, as shown in FIG. In addition to the cycle time and filling time, the product discrimination item 51 includes an integral value corresponding to each channel displayed on the waveform display screen. That is, when the control unit 13 obtains the integral value of the section designated on the waveform display screen, the control unit 13 stores the obtained integral value in the storage unit together with other product discrimination items.
[0034]
When the product discrimination monitoring screen is displayed on the display 12, the discrimination criterion 52 can be set for each product discrimination item. The discrimination standard 52 is given by the center value and the width, and is judged as a non-defective product if the value of each product discrimination item is within the range. If the discrimination criterion 52 is set, the control unit 13 performs pass / fail judgment. If there is a defective product, the number is displayed numerically and clearly indicated by inverting the display color of the data related to the product determined to be defective.
[0035]
As described above, according to the present embodiment, by adopting the integral value of shot data in an arbitrary section in the injection process as a non-defective product discrimination item, the filling amount is small and high-speed filling is performed in a short time. Even when molding a small and thin product that must be done, even if there is a slight difference from the operation at the time of molding a good product, it can be obtained as a large quantitative value, and it can be judged with higher accuracy. This can be done relatively easily even with slight changes in the setting conditions.
[0036]
Next, with reference to FIG. 6 and FIG. 7, an example in which the present invention is applied in the weighing step will be described as a second embodiment of the present invention. The configuration of the discrimination device for an injection molding machine according to the present invention is the same as that of the device according to the first embodiment.
[0037]
In the present embodiment, when the control unit 13 receives an instruction to display a waveform from the setting device 11, waveforms such as back pressure, screw rotation torque, screw rotation speed, cylinder temperature, or resin temperature in the measurement process are displayed. Display on the display unit screen. FIG. 6 shows an example in which the waveform of the screw rotation torque is displayed on the screen of the display 12.
[0038]
Also in the present embodiment, the control unit 13 causes the cursor to be displayed on the screen in accordance with an instruction from the setting device 11, obtains the integral value of the section designated by the cursor, displays the obtained integral value on the screen, Store as a product discrimination item.
[0039]
In the measuring step, the screw bites and melts the pellet-shaped resin in the heating cylinder. At this time, the melt density of the resin changes depending on the amount of air remaining between the resin particles. This change in melt density deteriorates the metering stability and lowers the quality of the molded product. Therefore, although it is desired to detect a change in melt density, the change appears as a continuous small waveform variation over the entire weighing process, as is apparent from the graph of FIG. For this reason, it is extremely difficult to detect a change in melt density directly from the graph of FIG. However, in the product discriminating apparatus according to the present embodiment, a change in the melt density can be easily detected by obtaining the integral value of the graph of FIG. 6 in an arbitrary section during the weighing process. In particular, since a large amount of resin is melted in a section other than the speed increasing region 77 where the screw rotation starts and the deceleration region 78 where the screw rotation stops, the integral value is obtained to detect a change in the density of the molten resin. Is effective.
[0040]
Here, as shown in FIG. 7, the arbitrary section includes a plurality of sections (for example, a first designated section 73 designated by the cursor 71 and the cursor 72, a second designation designated by the cursor 74 and the cursor 75). It may be a section 76). However, in order to designate a plurality of sections, it is necessary to display an “add cursor” button or the like for displaying a corresponding cursor on the screen. In this case, by arbitrarily selecting a plurality of sections, it is possible to easily check in which section in the measurement process the measurement stability varies. And based on the investigation result, it is possible to easily divide the weighing process into a plurality of sections and to set appropriate molding conditions for each section.
[0041]
As described above, according to the product discriminating apparatus according to the present embodiment, it is possible to discriminate kneading defects by using shot data such as screw rotation torque and back pressure obtained during the weighing process as non-defective product discriminating items. it can. Moreover, it becomes easier to specify the cause of the defect by designating a plurality of sections during measurement.
[0042]
Further, similarly to the first embodiment, the load of the screw rotation motor during the measurement process can be calculated by performing an operation such as integration based on the screw rotation torque waveform. As a result, occurrence of abnormality in the molding machine can be predicted in advance, and parts can be replaced and maintained, molding conditions can be changed, and production processes can be changed without hindering the production process being executed.
[0043]
Thus, in the product discriminating apparatus according to the present embodiment, by adopting the integral value of shot data in an arbitrary section in the weighing process as a non-defective product discriminating item, even if there is a slight difference from the operation at the time of good product molding. It can be obtained as a large quantitative value, can be judged with higher accuracy, and can be relatively easily changed even with a slight change in setting conditions.
[0044]
Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the graph displayed on the screen is not limited to the one in the injection process or the weighing process, but may be a waveform in the mold clamping process or the ejection process. Even in this case, as in the injection process and the weighing process, by performing calculations such as integration based on various waveforms in the mold clamping process and the ejecting process, the life of the parts of the injection molding machine can be predicted. By calculating the applied load, it is possible to predict the occurrence of an abnormality in the molding machine in advance. Therefore, the screw mechanism can be replaced, maintained, the molding conditions can be changed, and the production process can be changed without hindering the production process being executed. In addition, by selecting and calculating the section that has the greatest impact on the parts of the molding machine (such as the section with a large load), when calculating continuously for all sections in the molding process In comparison, the load applied to the control unit is very small. Furthermore, the molding conditions can be set relatively easily even for molded products that are difficult to distinguish.
[0045]
【The invention's effect】
According to the present invention, when shot data obtained from an injection molding machine is displayed as a waveform, an arbitrary section is designated and an integral value of the section is obtained, and the obtained integral value is adopted as a non-defective item determination item. Thus, it is possible to realize a pass / fail judgment with higher accuracy. Further, by obtaining the integral values in a plurality of sections, it is possible to easily specify the section or the setting condition that has the most influence on the molding, thereby facilitating the determination of an appropriate molding condition.
[Brief description of the drawings]
FIG. 1 is a block diagram of a product discriminating device for an injection molding machine according to an embodiment of the present invention.
FIG. 2 is a diagram showing an example of a waveform display screen displayed on the display of the product discrimination device of FIG.
FIG. 3 is a diagram showing a state in which a cursor is displayed on the waveform display screen of FIG. 2;
FIG. 4 is a diagram showing an example in which section designation is performed on a graph of injection pressure in an injection process.
5 is a diagram showing an example of a product discrimination monitoring screen displayed on the display of the product discrimination device in FIG. 1. FIG.
FIG. 6 is a diagram illustrating an example in which section designation is performed on a graph of back pressure, rotational torque, or cylinder temperature in a measurement process.
FIG. 7 is a diagram illustrating an example in which a plurality of sections are specified for a graph such as back pressure in a measurement process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Product discrimination | determination apparatus 11 Setter 12 Display 13 Control part 20 Injection molding machine 21 Channel button 22 Cursor button 31 Waveform display area 32, 33 Cursor 34, 35 Straight line 36 Cursor position display area 37 Area 51 Product discrimination item 52 Discrimination standard 71 , 72 Cursor 73 First designated section 74, 75 Cursor 76 Second designated section 77 Acceleration area 78 Deceleration area

Claims (11)

In the product discrimination device for an injection molding machine for discriminating the quality of the product molded by the injection molding machine,
A display, a setting device, and a control unit connected to the display device;
Wherein the control unit, the injection detection value of the injection pressure or the like from the detector provided in the molding machine in association with the time such as the detection data and to store the detection data in accordance with the setting from the setting device Is displayed on the display unit, and the detection data is displayed on the display unit as a function of the time or the like. An area designation designating an arbitrary area above is accepted, an integral value obtained by integrating the detected value such as the injection pressure in the designated area with respect to the time or the like is obtained, and the obtained integral value is used for the quality determination of the product. Used as an evaluation item,
A product discrimination device for an injection molding machine. The product discriminating apparatus for an injection molding machine according to claim 1, wherein the control unit displays the integral value on the graph display screen of the display. 3. The controller according to claim 1, wherein the controller receives an area designation for designating a plurality of areas from the setting device, and obtains an integrated value of the detection data for each of the plurality of areas. Product discrimination device for injection molding machine described in 1. The product detector for an injection molding machine according to any one of claims 1 to 3, wherein the detector is for detecting an operation of the injection molding machine during an injection process. The product detector for an injection molding machine according to any one of claims 1 to 3, wherein the detector is for detecting an operation of the injection molding machine during a weighing process. In a product discrimination method for an injection molding machine for discriminating the quality of a product molded by an injection molding machine,
The detected value such as the injection pressure from the detector provided in the injection molding machine is displayed as a graph on the display as a function of time, etc.
Using setter, specify any region with respect to the time and the like on the graph displayed on the display device,
Obtain an integrated value obtained by integrating the detected value in the specified region with respect to the time, etc.
Adopting the obtained integral value as an evaluation item for determining the quality of the product,
A product discrimination method for an injection molding machine. The product discriminating method for an injection molding machine according to claim 6, wherein an arbitrary plurality of areas are designated on a graph displayed on the display. The product discrimination method for an injection molding machine according to claim 6 or 7, wherein the arbitrary region is a region in an injection process. The product discriminating method for an injection molding machine according to claim 8, wherein an area including a time during which a filling peak pressure is obtained is specified as the arbitrary area. 8. The method for discriminating a product for an injection molding machine according to claim 6 or 7, wherein the arbitrary region is a region in a weighing process. 11. The product discrimination method for an injection molding machine according to claim 10, wherein an area other than the acceleration area and the deceleration area is designated as the arbitrary area.

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