JP2678686B2 - Molded product quality judgment method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded product quality determination method in which a controller for controlling an injection molding machine automatically determines the quality of a molded product molded by an injection molding machine.

2. Description of the Related Art A method for automatically determining the quality of a molded product molded in each molding cycle of an injection molding machine by a control device that controls the injection molding machine for each molding cycle is already known. For example, JP-A-2-48918 discloses a method of sampling the resin pressure in the injection step, comparing it with the resin pressure at each sampling which is a preset reference, and determining the quality of the molded product based on the comparison result. It is known.

Also, by measuring the time from the start of injection, the screw position when the set time is reached is within the set range, or whether the injection pressure is within the set range. There is also a special method for determining the quality of the molded product, such as determining whether the molded product is good or bad by judging whether the injection pressure at the set screw position during injection is within the set range. It is publicly known in Japanese Patent Laid-Open No. 2-78516.

In addition, the values that represent various operating conditions during the molding cycle are used as monitoring items, the values of these monitoring items are detected for each molding cycle, and if there is a detected value within the setting range set for each item, that molding cycle There is also known a method of judging the quality of a molded product formed by the method of (1) to judge whether the molded product is good or bad, and if it is out of the range, it is judged as a defective product to judge the quality of the molded product (for example, JP-A-2-106315).
Reference). In this case, if at least one of the multiple monitoring items does not have a detected value within the setting range, it is determined to be defective, or if all the monitoring items have detected values within each setting range, the molded product is judged to be good. The method of doing was adopted.

Problems to be Solved by the Invention When even one of a plurality of monitoring items has no detected value within the setting range set for the monitoring item, the molded product molded in the molding cycle is regarded as a defective product. In this case, a good product may be determined to be a defective product. This is because the values representing the respective operation states in the molding operation are mutually related, so that a good molded product may be molded even if one monitoring item is not within the set range. Also,
Even if it is determined that one monitoring item is a non-defective product, a defective product may be molded (the values representing the operating states of other monitoring items are not suitable values).

In addition, if it is determined that the molded product is defective when it is determined that the detected values are not within the setting range for all the monitoring items, the probability that even a defective product will be determined as a good product increases.
There are cases where the quality judgment is wrong.

Therefore, an object of the present invention is to provide a molded product quality determination method that eliminates the determination error as much as possible in the method of determining the quality of a molded product based on a plurality of monitoring items.

Means for Solving the Problems Various operating states during one cycle of molding a molded product are detected as monitoring items for determining the quality of the molded product, and after the completion of one cycle, the control device of the injection molding machine automatically performs the monitoring items. In the molded product determination method of determining whether each of the detected values is within the set range and determining the quality of each molded product, the present invention provides the setting range width of each monitoring item to be determined as a non-defective product. The combination is regarded as a non-defective condition, and a plurality of the setting range widths and combinations of the setting range widths are set and stored in the storage device of the control device, and the monitoring items of each monitoring item detected during the cycle after one molding cycle are finished. It is determined whether or not the value is within the set range width of each monitored item of the non-defective condition stored above, and within the set range width of each monitored item of the combination of the set range widths stored as at least one non-defective condition. There is everything At this time, the molded product molded was made to be a good product.

Action Good product conditions in which the setting width of each monitoring item that makes a molded product a non-defective product and the combination of the setting widths are set are stored in a plurality of storage devices, and detected during the cycle at the end of one molding cycle. It is judged whether or not the values of each monitoring item are all within the setting range of the corresponding monitoring item of one non-defective item condition, and if even one is not within the setting range, the same judgment is sequentially made for the next non-defective item condition. If there is any value of the detection monitoring item corresponding to the setting range width of each eye monitoring item of any one combination of the setting range widths of the non-defective product conditions, the molded product molded in the cycle is regarded as a non-defective product. In addition, if the values of the detection and monitoring items are not satisfied under all the conditions of non-defective products, the molded product is determined to be defective.

Example Hereinafter, an example of the present invention will be described.

FIG. 3 is a block diagram of a control device for an injection molding machine according to an embodiment of the present invention. In this embodiment, the control device is constituted by a numerical control device (hereinafter referred to as NC device) 10. The NC device 10 is a microprocessor for NC (hereinafter referred to as CP).
U) 11 and a CPU 12 for a programmable machine controller (hereinafter referred to as PMC). The PMC CPU 12 temporarily stores data such as a ROM 18 storing a sequence program for controlling a sequence operation of the injection molding machine, A RAM 19 used for calculation and the like is connected.

In the CPU 11 for the NC, a ROM 14 storing a management program for controlling the entire injection molding machine and a servo circuit 17 for driving and controlling the servomotors of each axis for injection, clamping, screw rotation, ejector, etc. Face 16
Connected through. Also, 20 is a bubble memory or CM
A non-volatile shared RAM composed of an OS memory, a memory unit that stores NC programs that control each operation of the injection molding machine, a molding condition memory unit that stores set molding conditions,
And a table memory unit for storing the setting range for each monitoring item of each non-defective condition.

13 is a bus arbiter controller (hereinafter called BAC)
In the BAC 13, the CPU 11 for NC and the CPU 12 for PMC, the shared RAM 20,
Each bus of the input circuit 21 and the output circuit 22 is connected, and the bus to be used is controlled by the BAC 13. The input circuit 21 is connected to input lines from various sensors and peripheral devices provided in the injection molding machine, and the output circuit 22 is connected to output lines to various actuators and peripheral devices of the injection molding machine body. . 24 is an operator panel controller 23
Is a manual data input device with a CRT display device (hereinafter referred to as CRT / MDI) connected to the BAC13 via the BAC13. Various commands and setting data can be input by operating various operation keys such as soft keys and numeric keys. I can do it.
A RAM 15 is connected to the NC CPU 11 via a bus and is used for temporary storage of data. Although not shown, a floppy disk controller or the like as an external storage device is connected to the operator panel controller 23.

The above configuration is substantially the same as the control unit (NC device) of the injection molding machine controlled by the conventional NC device.

 Next, the setting of non-defective product conditions will be described first.

When the function menu keys and function keys provided on the CRT / MDI24 are operated to enter the non-defective condition setting function mode, the PMC CPU 12 starts the process shown in the flowchart in FIG. 2 and sets the index j to "1". (Step S10
1), the index j from the non-defective condition table memory part of the shared RAM 20
The non-defective condition table shown by is read out and displayed on the display screen of the CRT / MDI 24 as shown in FIG. 4 (step S102). In this embodiment, whether or not the molded product is a good product is determined by the "cushion amount",
An example is described in which three monitoring items, "injection time" and "weighing time" are used. If necessary, in addition to the above monitoring items, "measurement position", "peak injection pressure", "position of screw for switching from speed control to pressure control during injection", "cycle time", "cylinder temperature", "nozzle""Temperature","Temperature of resin supply port", "Mold temperature", "Platen temperature", "Ambient temperature", "Ratio of heater ON / OFF time", "Injection pressure when a predetermined time has elapsed after the start of injection "," Screw position when a predetermined time has elapsed after the start of injection "and the like may be used as monitoring items.

If the non-defective condition is not set, “0” is stored as the upper limit value and the lower limit value of each monitoring item, and this is displayed.

Next, the PMC CPU 12 determines whether or not there is a key input (step S103), and if there is a key input, that input corresponds to the function key function display f1 to f3 on the CRT screen. ) Or "Next good condition" key (f2)
It is determined whether it is a cursor movement key, a data input key for inputting data, a "not used for discrimination" key (f3), or a key on another screen (other function) (steps S104 to S109).

When the operator operates the cursor movement key to set the range of monitoring items (step S106), the cursor is moved in the direction of the operated cursor movement key, and the cursor is stopped at the position selected by the operator (step S117). . Next, when a numerical value is input by the numerical key and the data input key is operated (step S107), the input numerical value is set in the item at the position of the cursor and the value in the table memory of the non-defective condition is rewritten ( Step S11
8). Then, the value of the item on the CRT screen is rewritten and displayed as the input value (step S119). Next, register M
And the value of the index j at the present time is compared (note that the register M stores “0” when no good condition is set), and only when the value of the index j is large. The value of this index is stored in the register M and the process returns to step S103 (steps S120 and S121). Hereinafter, every time the data input key is operated, the processes of steps S107 and S118 to S121 are performed, and the range width for judging the molded product of each monitoring item as a non-defective product is set and displayed. That is,
In the example shown in FIG. 4, if the cursor is positioned at the upper limit or the lower limit of each monitoring item and data is input, the setting range of each monitoring item will be stored as shown in FIG.

In this way, the setting width of each monitoring item is set.
There is one non-defective product condition, that is, a combination of setting widths of each monitoring item, and a combination of setting widths of each monitoring item that may judge a molded product as a non-defective product. The value of each monitoring item at the time of molding is measured and obtained, and is sequentially set as a good product condition. For example, the fourth
In the example shown in the figure, when the width of the cushion amount is 2.50 to 3.00 mm, the injection time is 1.50 to 2.00 seconds, and the measurement time is 14.00 to 15.00 seconds, the non-defective product condition 1 is set as a non-defective product. However, if the cushion amount deviates from this setting range and the injection time and the measuring time are within the range smaller than the setting range of these monitoring items of the good product condition 1, if a good product is molded,
Such good product conditions are also set. For example, if the cushion amount is within 2.30 to 3.20 mm, the injection time is within 1.70 to 1.90 seconds, and the weighing time is within 14.20 to 14.80 seconds, it is assumed that a good product will be molded. The width combination is also set as a non-defective condition.

In this case, if the operator operates the function key (f2) of "next good product condition" (step S105), PN
The C CPU 12 increments the index j by "1" and sets the index j to "1" if the index j exceeds the number N of non-defective condition table memories provided in the shared RAM 20, and the index j if not. The value of j is not changed (steps S111 to S113), and the process returns to step S102 to display the non-defective condition table memory corresponding to the index j. Then, as described above, the cursor movement key, the numeric key, and the data input key are operated to input and set the setting width for each monitoring item (steps S106, S117, S107, S11).
8 ~ S121).

In this way, the combinations of the setting widths of the respective monitoring items in which a good molded product is formed are set and stored as good product conditions.

Also, when changing the non-defective condition once set,
Operate the function key (f1) of "Previous good product condition" to call the good product condition to be changed on the CRT screen.
When the function key (f1) of "previous good condition" is operated (step S104), the index j is decremented by "1", and when the value of the index j is "0" or less, the index j is stored in the shared RAM 20. Number of non-defective condition table memories prepared in N
If it is larger than “0”, the index value is not changed (steps S114 to S116) and the process returns to step S102. In this way, each time the function key (f1) of "previous good product condition" is operated, the previous good product condition is displayed, and the function key (f2) of "next good product condition" is operated. The following non-defective conditions are displayed for each item, and the non-defective conditions to be displayed, set, and changed can be selected.

In addition, when there is a monitoring item that is not used as a non-defective item condition, that is, when there is a detected value of that monitoring item within the setting range of another monitoring item, it is regarded as a non-defective item, and when the judgment by that monitoring item is not made, the cursor is moved to the relevant monitoring item. When positioned at the upper or lower limit of the item and the function key (f3) "Not used for discrimination" is operated (step S108),
If the cursor is at the upper limit position, + infinity (maximum settable value) is set for that item, and if it is at the lower limit position, −infinity (minimum settable value) is set (steps S122 to S12).
4) and returns to step S102.

As described above, each non-defective condition is set and a plurality of non-defective conditions are set in the shared RAM 20 as shown in the explanatory view of FIG.

When the operator sets the non-defective condition and operates the function menu key, function key, etc. to select another screen (step S109), the CRT screen switches to the selected screen (step S110). The condition setting process ends. Then, when data is input to the register M, that is, when upper or lower limit data indicating the range of monitoring items is input, this indicates that a non-defective condition is set, and this non-defective condition is set. Since the maximum value of the set value of the index j is stored, the register M stores the number from the first set good condition. FIG. 1 is a flow chart showing the process of one cycle for molding a molded product. When one cycle as the molding operation of mold closing, injection, pressure holding, metering, mold opening and eject is completed as in the conventional case (step S1 ~ S6), PM
The C CPU 12 sets the non-defective item flag F to "0" and the index j to "1" (steps S7 and S8). Then, as in the conventional case, the values of the monitoring items detected during the one molding cycle, in the example of this embodiment, the cushion amount CS, the injection time IT, and the measuring time ET are stored in the non-defective condition table memory corresponding to the index j. It is judged whether or not it is within the setting range of each monitoring item. That is, whether the detected cushion amount CS is between the upper limit CSHj and the lower limit CSLj of the cushion amount set as the non-defective condition j (CSLj ≦ CS ≦ CSHj), the detected injection time IT is set to the upper limit ITHj of the set injection time width. Whether it is between the lower limit ITLj (IT
Lj ≤ IT ≤ ITHj), and whether the detected weighing time ET is between the upper limit ETHj and the lower limit ETLj of the set weighing time width (ETLj ≤ ET ≤ ETHj) (steps S9 to S14), even one is within the setting width. If not, the process proceeds to step S16, "1" is added to the index j, and it is determined whether or not the index j exceeds the value of the register M that stores the number of the non-defective product conditions set (step S17). ,
If it does not exceed, the process returns to step S9, and it is determined whether or not the detected value of each monitoring item is within the set range for the next conforming product condition (steps S9 to S14). Below, it is judged whether or not there is a detection value for each monitoring item within the setting range for each monitoring item under each non-defective condition, and all values for each detection monitoring item are included within the setting range for each monitoring item under the non-defective condition. In this case, the non-defective item flag F is set to "1" (step S15), and the process proceeds to step S18. In addition, it is sequentially judged whether or not the detection monitoring items are within the setting range of each monitoring item of each non-defective item condition, and all the checks are performed for the set non-defective item condition, and all the non-defective item conditions are satisfied. If the index j exceeds the number M of the non-defective product conditions set (step S17), the non-defective product flag F is not set to "1" and the process proceeds to step S18.

In step S18, it is judged whether or not the non-defective flag F is "1", and if it is "1", a non-defective signal is output (step S1
9) If not "1", a defective product signal is output (step S20), and the molding 1 cycle processing is ended.

In the above embodiment, the quality judgment of the molded product is made only for the set good product conditions, but the good / bad judgment is made for all the good product conditions of the good product condition table memory provided in the shared RAM 20. You may do it. In this case, steps S120 and S in the flowchart of FIG.
The process of 121 is not necessary, and in the flowchart shown in FIG. 1, it is determined in step S17 whether the value of the index j exceeds the number N of memory tables. Then, since the setting value of each monitoring item is “0” in the memory table in which the non-defective condition is not set, the value of each detected monitoring item does not fall within the setting range, and the non-defective condition is not set. In some cases, the non-defective item flag F may not be set to "1". That is, the quality judgment of the molded product is not performed under the non-defective product condition that is not set. Then, if the condition of the non-defective product set is satisfied, the non-defective product flag F is set to "1".

Further, the value of the register M may be manually changed. In this case, the strict non-defective condition is set in advance. That is, the non-defective condition 1 is set to be the most severe non-defective condition, and the non-defective condition 2 is set to the next most severe condition,
Set in order from the strictest to the following. Then, the number of non-defective product conditions for determining acceptability is determined based on the environmental condition around the injection molding machine, the climatic condition of the day, the pellet condition of the molding material, and the like, and the value is set in the register M.

In addition, regardless of the strictness of the quality determination condition, the quality condition may be set and the good product condition to be used may be set. In this case, the set good product condition is sequentially read and the quality determination is sequentially performed. Will be done.

Further, the above-mentioned good product conditions may be written and stored in an external storage device such as a floppy disk, and when the same molded product is molded again, the good product conditions stored in this external storage device may be loaded into the shared RAM 20. Good.

EFFECTS OF THE INVENTION Since the quality of a molded product under a plurality of non-defective conditions is determined, that is, the quality of a molded product is determined under a plurality of non-defective conditions with different combinations of monitoring item setting widths, a non-defective product is regarded as a defective product. The probability of doing so becomes smaller, and the quality of the molded product can be determined more accurately.

[Brief description of the drawings]

FIG. 1 is a flowchart of a molding cycle including molded product quality determination processing in an embodiment of the present invention, FIG. 2 is a flowchart of non-defective product condition setting in the embodiment, and FIG. 3 is an injection for implementing the embodiment. FIG. 4 is a block diagram of a main part of a control device of the molding machine, FIG. 4 is a diagram showing an example of a non-defective condition setting screen in the same embodiment, and FIG. 5 is an explanatory diagram of a non-defective condition table memory. 10 ... Numerical control device as a control device, f1, f2, f3 ... Function key function display.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuaki Neko 3580 Kobaba, Ogino-za, Oshino-mura, Minamitsuru-gun, Yamanashi Pref.

Claims (1)

(57) [Claims] Claims: 1. Various operating states during one cycle of molding a molded product are detected as monitoring items for judging the quality of the molded product,
In a molded product discriminating method, after the completion of one cycle, the control device of the injection molding machine automatically judges whether or not the detected values of the monitoring items are within the set ranges, and judges the quality of each molded product. A setting range width for determining a non-defective item is set for each of the monitoring items, and a combination of the set range widths for determining a non-defective item is set and stored in the storage device of the control device as a non-defective item condition. After the completion of one molding cycle, it is judged whether or not the value of each monitoring item detected during the cycle is within the set range width of each monitoring item of the above-mentioned stored non-defective condition, and the value is stored as at least one non-defective condition. A method for determining the quality of a molded product, in which a molded product that is molded is regarded as a non-defective product when all of the monitoring items of each combination of setting range widths are within each setting range.