JPS63209918A - Method for setting molding conditions of injection molder - Google Patents

Abstract

PURPOSE:To simplify the molding setting operation at molding and realize the high quality molding and consequently contrive to reduce the cost by a method wherein the optimum conditions of a mold is inferred from data base inputted in a computer. CONSTITUTION:A preliminary injection is done so as to detect the injection pressure in the rear oil chamber 15a of an injection cylinder 15 during the advancing movement of a screw with a pressure sensor 22, the position of the screw with a positional sensor 24 and further the pressure in the cavity of a mold 2 with an inner pressure sensor 23 in order to data-process detected values and to store them in a memory 4. The accuracy of injection is improved by calculating and inferring whether said detected values are equal to the set values or not at an arithmetic processing unit 21. After the repetition of the inference of set conditions as described above, the optimum molding conditions of a mold 2 is searched from the data base stored in the memory 4 and inferred from the knowledge base in the memory 4. Thus, the setting operation of molding conditions is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention particularly relates to a method of setting molding conditions for an injection molding machine that simplifies the setting work.

[Background and issues]

In general, in injection molding machines that mold synthetic resin materials, molding conditions vary greatly depending on the size, shape, number of products, etc. of the mold. For this reason, molding conditions such as multistage injection speeds, shift points, multistage injection pressures, and pressure transformation points are set in detail for each mold.

By the way, when setting the molding conditions, each condition is interrelated, so simply setting one condition element theoretically will not yield the optimal molding condition, and each condition may be slightly different. Since it affects the quality of molded products, its theoretical setting is also difficult.

Therefore, in the end, operators who have a wealth of experience and advanced knowledge have no choice but to rely on their own judgment and intuition, and the settings require a long time of trial and error. with loss of material and energy.

As described above, the setting of molding conditions is the biggest impediment when starting up production, and an effective technical solution is required.

[Means for solving problems]

The present invention aims to provide a novel method for setting molding conditions in an injection molding machine that meets the above requirements, and is achieved by the method for setting molding conditions described below.

That is, in the method for setting molding conditions of an injection molding machine according to the present invention, at least data Di1 regarding the mold 2, such as type, size, shape, number of products, etc., are sent to the computer 3, preferably by AI (Artificial Intelligence).
all or part of the molding conditions by inputting them into the computer and searching and/or inferring the molding conditions suitable for the mold 2 based on the database and/or knowledge base regarding molding conditions stored in the memory 4 in advance. It is characterized in that it can be set.

[For production]

Next, the operation of the present invention will be explained.

In the method for setting molding conditions for an injection molding machine according to the present invention, data Di regarding the mold 2 or necessary data such as the molding material are first input into the computer 3. As a result, the computer 3 searches for the optimal molding conditions for the mold 2 from the database stored in the memory 4, or depending on the molding conditions, the computer 3
The optimal molding conditions for the mold 2 are derived by inference from the knowledge base in the memory 4 using the inference function of the computer.

This allows the computer to set all or part of the molding conditions that belong to experience and know-how, thereby simplifying the setting work.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

Fig. 1 is a schematic block diagram of an injection molding machine that can carry out the method of the present invention, Fig. 2 is a block system diagram showing the method step by step, and Fig. 3 shows an injection molding machine suitable for carrying out the method. The configuration diagram and FIG. 4 are explanatory diagrams showing a procedure for setting molding conditions including the same method.

First, in order to facilitate understanding of the present invention, a schematic configuration of an injection molding machine that can utilize the method of the present invention will be described.

In FIG. 1, an injection molding machine, designated as a whole by reference numeral 1, is equipped with a known molding machine main body 1a, a mold 2, and a control system 5.
Equipped with 3 I-computers. Note that 6 is a keyboard for inputting required data to the AI computer 3a.

Note that peripheral devices such as a display device are omitted in FIG.

Next, with reference to FIG. 3, the configuration of the injection molding machine 1 will be explained.
This will be explained more specifically. In FIG. 3, the same parts as in FIG. 1 are given the same reference numerals.

The molding machine main body 1a is of an in-line screw type, and includes a heating cylinder 13 having a screw 11 inserted therein and an injection nozzle 12 at the front end. In addition, there is a screw 11 at the rear.
an injection cylinder 15 into which a ram 14 connected to the rear end is inserted;
and an oil motor 16 that rotates this ram 14.

Further, the rear oil chamber 15a of the injection cylinder 15 is connected to a hydraulic pressure source 18 via a control device 17 consisting of an electromagnetic proportional flow valve, an electromagnetic proportional pressure valve, an electromagnetic directional switching valve, and the like. This control device 17 is controlled by a sequence controller 20 to which a predetermined setter group is connected.

On the other hand, 21 is an arithmetic processing unit, and 4 is a memory, which form the core of the AI computer 3a. A. The computer 3a has arithmetic functions similar to those of a normal computer, as well as an inference function, and deduces the optimum molding conditions for the mold 2 to be molded based on the database and knowledge base.

Therefore, the memory 4 contains a database of molding pattern data for each molded product molded in the past, molding machine performance specification data, molding material characteristic data, etc., as well as necessary basic knowledge, know-how, rules, and an expert system described later. It stores knowledge bases such as diagnostic programs for investigating the causes of defects. Note that inference includes not only searching for the most similar molding condition pattern from past databases, but also making a judgment based on input data and constructing unique molding conditions required by the input data.

Furthermore, detection information from various sensors is input to the arithmetic processing unit 21 . In each sensor, 22 is a pressure sensor that detects the oil pressure in the rear oil chamber 15a of the injection cylinder 15, 23 is an internal mold pressure sensor that is attached to the cavity of the mold 2 and detects the internal pressure of the mold, and 24 is the advance/retract position of the screw 11. This is a position sensor that detects the position of the projection 25 that follows the rear end of the screw 11 using a linear encoder, rotary encoder, potentiometer, etc. In addition,
The output signals of the respective sensors 22-24 are manually inputted to the arithmetic processing unit 21 via amplifiers 26-28. Note that for ease of understanding, only sensors necessary for the embodiment are illustrated, but various sensors can be added as necessary.

Furthermore, the arithmetic processing unit 21 is connected to the aforementioned keyboard 6, sequence controller 20, and further a display device 29 using a CRT, plastic display, Zuma display, or the like.

Next, a method for setting molding conditions according to the present invention will be explained with reference to FIGS. 2 to 4.

In this embodiment, a case will be described in which molding conditions for the speed control region shown in FIG. 4(d) are set for a molded product having the shape shown in FIG. 4(c). In addition, in the same figure (C), 41
denotes a product section, 42 a gate, 43 a runner, and 44 a sprue.

First, data regarding the mold 2 is input from the keyboard 6 to the arithmetic processing unit 21 . The data regarding the mold 2 includes data that can be known in advance, such as cavity dimensions, capacity, projected area, product type, number of products, sprue and launch capacity, gate type, number of gates, gate volume, etc. The data entered at this time requires at least data regarding the mold, but by further inputting data regarding the injection molding machine used, the resin material used, etc., it is possible to determine whether or not molding can be performed with the injection molding machine used. , the optimum molding temperature is set for the resin material used.

By inputting this data, the AI computer 3a searches for optimal molding conditions for the mold 2 based on the database and knowledge base stored in the memory 4, and further performs inference.

In addition, in the injection molding machine, the reason why the inference function by the AI computer 3a is necessary is as follows.

That is, data Di related to the mold is inputted in advance from the keyboard 6, and this data Di may include some data related to the mold such as the shift point (shift position), the transformation point (transformation timing), etc. It is difficult to prepare and input all the data regarding the mold in advance. Furthermore, it is not possible to prepare and input data related to molding characteristics based on the combination of the molding machine main body 1a and the mold 2, such as the flow of the resin within the mold 2, changes in characteristics due to behavior, response delays, etc. . By the way, this type of data has conventionally been supplemented by the operator's experience and intuition. Therefore, even if a database is used, molding data with exactly the same conditions may exist in the past.
If you select it as is, it is possible to set the conditions, but if this is your first mold, inputting data from the keyboard 6 will not be able to set the settings due to insufficient information.

Therefore, the inference function of the AI computer 3a is used to infer unknown parts and set all or part of the molding conditions. This increases the accuracy of the inference results and sets the final molding conditions.

Next, the specific setting method will be described step by step.

As the molding conditions in the speed control region as shown in FIG. 4(d), test injection can be performed if a series of injection speeds and resin capacity (residual value) are set to the minimum.

First, as mentioned above, input the data regarding mold 2,
The injection speed Vl, V is determined by the function of the AI computer 3a.
2. V3 and further set the resin material measurement position 5l (=molded product volume + cushion amount).

Here, the -th preliminary injection is performed. In this case, for the injection speed, refer to the above injection speeds VISV2 and v3; set the low speed that allows filling to 1st speed, and set the metering position to about 80% of the set metering position St, and then perform metering. conduct. The purpose of setting the measuring position in this way is to prevent damage to the mold, so start with a short shot. Further, the pressure (injection pressure) in the rear oil chamber 15a of the injection cylinder 15 is continuously detected by the pressure sensor 22 when the screw moves forward. Also, the screw position is determined by the position sensor 2.
4 and differentiated according to the measured time and stored in the memory 4 as position data. Furthermore, the mold internal pressure sensor 23 detects the internal pressure of the cavity, and a display device 29 displays the test firing pressure, test firing speed, and changes in the mold internal pressure with respect to the hex screw position in waveforms.

Further, it is determined by calculation whether the detected value of the injection pressure is equal to the set value. In this case, if the maximum detected value has reached the set value, the speed cannot be maintained at this set pressure due to the load pressure caused by the flow resistance in the mold, so the set pressure is gradually increased until the detected value does not reach the set value. . The reason why the measuring position is set at approximately 80% of the planned setting value is to allow the measuring value to gradually increase by a predetermined amount until the filling is completed. This prevents the injection pressure from rising suddenly at the end of the stroke.

The above settings are automatically executed by the arithmetic processing unit 21. By performing test firing in this manner, the accuracy of the inference is increased, and further developed conditions for the second preliminary firing are set.

Next, a second preliminary injection is performed and the shift point is set.

In this preliminary injection, each sensor 22 to 24 is
Detect data by. Then, the injection pressure with respect to the screw position is displayed in a waveform as shown in FIG. 4(a), and the slope is determined by differentiating the injection pressure with respect to the screw position as shown in FIG. 4(b). This slope changes depending on the load pressure behavior, and in the mold shown in Fig. 4(C), the
, X2, and X3, the slope increases. In addition,
Position Xl is the injection start point, position X2 is the gate passing point, and position X3 is the filling completion point. These positions Xl-X3 are important points in controlling the injection process. For example, if the injection speed is high when passing through the gate, jetting will occur, and if the injection speed is high when filling is completed, paring will occur.

These positions X1 to X3 correspond to shift points (control switching points) that have almost the same pattern depending on the shape of the molded product and the shape of the resin path.

Therefore, position X2 is the first shift point S2, position X3 is the control switching position S4 from the speed control area to the pressure control area, and furthermore, taking into account the response delay of the injection molding machine, the shift is made to ensure that the injection speed v3 is reached at position S4. Each point is set at position S3.

This completes the setting of the main molding conditions in the speed control area. Note that the same setting can be made in the pressure control region. In addition, other detailed operating conditions can be input from the keyboard 6 or memo IJ''4 if necessary.
Search and set the most similar pattern from the database. For example, the injection time and cooling time from the start of injection to the completion of gate sealing can be calculated and set from the injection speed, gate diameter, and characteristics of the resin material, the pressure application time in the pressure control area, the screw rotation speed during metering, the screw Back pressure etc. can be set to similar pattern values.

Further molding is performed under the conditions set in this way, and once it is confirmed that each actual value approximately matches the set value, the injection time (mainly the holding pressure time) is gradually shortened, and the mold internal pressure at that time is adjusted to the previous value. Shorten the injection time until the mold internal pressure drops compared to the data.

Then, the direct injection time during which a drop in mold pressure is observed is reset as a set value. Note that the pressure inside the mold decreases because the gate sealing is not completed and the pressure escapes to the molding machine main body la side.

The above condition setting is automatically executed according to the program in the memory 4.

Then, molding is performed according to the set molding conditions, and the operator looks at the molded product and determines whether it is a good product or not. In the case of a defective product, the expert system built by the AI computer 3a analyzes the cause of the defect, makes final fine adjustments, and obtains a non-defective product according to a diagnostic program using an expert system built by the AI computer 3a. It is stored and becomes part of the database and knowledge base. Incidentally, FIG. 2 shows the procedure for setting the above-mentioned molding conditions in units of blocks.

Although the embodiments have been described in detail above, the present invention is not limited to these embodiments.

For example, the term "molding conditions" is a concept that includes not only conditions necessary for actual molding but also preliminary conditions that cannot be used directly for molding. Furthermore, although the description has mainly been given to setting conditions on the molding machine main body side, the present invention can also be applied to the mold clamping side. Furthermore, although an in-line screw type injection molding machine is shown as an example, it can be similarly applied to other types of injection molding machines such as a plunger type. Other changes may be made in the detailed structure, shape, procedure, method, etc. without departing from the gist of the present invention.

〔Effect of the invention〕

As described above, the method for setting molding conditions for an injection molding machine according to the present invention inputs at least data regarding the mold into a computer, and determines the optimal molding for the mold based on the database and/or knowledge base regarding molding conditions stored in a memory in advance. Since all or part of the molding conditions are set by searching and/or inferring the conditions, the following effects are obtained.

■ Since the main initial molding conditions are automatically set on a computer using data related to the mold, the operator only needs to make final fine adjustments as necessary. Therefore, the setting work can be significantly simplified, and work efficiency can be dramatically improved by shortening the setting time and reducing labor.

■ Since it does not rely on the operator's own intuition, there is no variation in settings, allowing highly accurate molding conditions to be set, contributing to high-quality molding.

■ Wasted materials and energy loss associated with setting work can be significantly reduced, contributing to cost reduction.

[Brief explanation of the drawing]

Figure 1: A schematic block diagram of an injection molding machine capable of implementing the method of the present invention; Figure 2: A block system diagram showing the method step by step; Figure 3: A configuration diagram of an injection molding machine suitable for implementing the method. , FIG. 4: An explanatory diagram showing a procedure for setting molding conditions including the same method. In the drawings, 1: Injection molding machine 2: Mold 3: Computer 4: Memory Di2 Data regarding the mold

Claims (1)

[Claims] All or part of the molding conditions are determined by inputting at least data regarding the mold into a computer, and searching and/or inferring molding conditions that are compatible with the mold based on a database and/or knowledge base regarding molding conditions stored in a memory in advance. A method for setting molding conditions for an injection molding machine, the method comprising: setting a molding condition for an injection molding machine.