JP4396819B2 - Material replenishment detection method and molding condition optimization method - Google Patents

Description

  The present invention relates to a material replenishment detection method for detecting whether or not material replenishment is properly performed during casting or injection molding, and a molding condition optimization method performed using the method.

  For example, in die casting, if the mold design such as the gate width and gate position, or the injection conditions (filling conditions) such as molding pressure and molding temperature are not appropriate, molten metal replenishment (material replenishment) into the cavity is not possible. It becomes sufficient, and a shrinkage cavity (casting cavity) that causes a decrease in strength occurs in the cast product. However, conventionally, there is no effective means or method for grasping whether or not this molten metal replenishment has been properly performed. Generally, after casting is finished, the cast product is cut, or X-ray flaw detection, ultrasonic flaw detection, etc. A destructive inspection was performed to confirm the presence or absence of a cast hole, and the molding conditions were optimized based on the results of these confirmations.

  In some cases, after the molten metal is filled in the cavity of the molding die, ultrasonic waves are incident on the cavity, and the condition of the molten metal solidifying is recognized from the reflected wave, and the molding conditions are changed. (For example, refer to Patent Document 1).

JP-A-5-329611

However, according to the conventional method for optimizing the molding conditions, when a cast product is cut, waste is generated if it is a non-defective product, and special measurement is performed when performing non-destructive inspection. There was a problem that a device was necessary and in either case, the cost burden was large.
Further, according to the method described in Patent Document 1, the reflected wave from the boundary between the solid phase and the liquid phase of the molten metal is observed (paragraph 0008 of the publication) or the reflected wave from the nest is observed. (Paragraph 0010 of the publication), such a detection method cannot accurately grasp the suitability of molten metal replenishment, and there remains a problem in terms of reliability.

  The present invention has been made in view of the above-described conventional problems, and the problem is to provide a material replenishment detection method capable of accurately detecting the suitability of material replenishment during molding. An object of the present invention is to provide a molding condition optimization method that optimally changes the molding conditions based on the result obtained by this detection method.

  As a result of earnest research on the waveform of the reflected wave when the ultrasonic wave is incident into the cavity after filling the molten material, the present inventors have found that the reflected wave reflected from the molding surface on the side opposite to the incident side of the ultrasonic wave. It has been found that the intensity level change is significantly different between when the material is fully replenished and when not enough. That is, when the material is sufficiently supplied, as shown in FIG. 4, two peaks P1 and P2 are recognized in the intensity level change of the reflected wave, whereas when the material is not sufficiently supplied, As shown in FIG. 5, only one peak P1 is recognized in the intensity level change of the reflected wave.

  The present invention has been made on the basis of the above-described knowledge. In the material replenishment detection method according to the present invention, after a molten material is filled into a cavity of a molding die, an ultrasonic wave is incident on the cavity, It is characterized in that when at least two peaks are observed in the temporal change in the intensity level of the reflected wave reflected from the molding surface opposite to the incident side, it is determined that material replenishment has been appropriately performed.

  The molding method to which the present material replenishment detection method is applied is arbitrary, and may be casting or injection molding. Accordingly, the type of the molten material is naturally determined depending on the molding method to be applied, and when applied to casting, a metal is selected as the molten material, and when applied to injection molding, a resin is selected as the molten material.

The molding condition optimization method according to the present invention is based on the detection result by the material replenishment detection method described above, and only one peak is present in the time change of the intensity level of the reflected wave reflected from the molding surface opposite to the ultrasonic incident side. However, when it is determined that the material supply is insufficient, the molding conditions are changed so that the shortage of the material supply is resolved. The change of the molding condition in this case may be a change of the mold shape for expanding the gate width, or a change of the filling condition for an increase in molding pressure or molding temperature.

According to the material replenishment detection method according to the present invention, since it is possible to accurately grasp whether or not material replenishment has been properly performed during molding, it is not necessary to perform destructive inspection or non-destructive inspection after molding, and cost burden Becomes smaller.
Further, according to the molding condition optimization method according to the present invention, the molding condition is changed so as to achieve the optimum material supply based on the result obtained by the material supply detection method, so that the molded product with less shrinkage nests. Can be obtained stably.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a die casting apparatus to which a material replenishment detection method according to the present invention is applied. In the figure, 1 is a molding die and 2 is an injection device. The molding die 1 is composed of a fixed die 3 and a movable die 4. The movable die 4 is combined with the fixed die 3, that is, in a closed state, and a cavity 5 serving as a casting space is interposed between the two. The runway 6 and the gate 7 are defined. The injection device 2 includes an injection sleeve 8 connected to the fixed mold 3 in communication with the runner 6 and a plunger 9 slidably disposed in the injection sleeve 8.

  The plunger 9 of the injection device 2 is driven by an injection cylinder (not shown), and as the plunger 9 advances, a predetermined amount of molten metal (molten metal) M supplied in advance into the injection sleeve 8 is obtained. The cavity 5 is filled from the runner 6 through the gate 7 into the cavity 5 at high speed and high pressure. The molten metal M filled in the cavity 5 gradually solidifies from the portion that contacts the molding surface 3a of the fixed mold 3 and the molding surface 4a of the movable mold 4, and the liquid phase L and the solid phase S coexist in the middle stage. It becomes a state to do.

  In the present embodiment, an ultrasonic sensor 10 is fixed on the back surface of the movable mold 4 constituting the molding die 1. The ultrasonic sensor 10 includes an ultrasonic transmission / reception element, to which an ultrasonic transmission / reception device 11 is connected. The ultrasonic wave (transmission wave) emitted from the ultrasonic sensor 10 passes through the movable mold 4 and enters the cavity 5 from the molding surface 4a, and is further fixed through the molten metal M filled in the cavity 5. While reaching the molding surface 3 a of the mold 3, the reflected wave therebetween is received by the ultrasonic transmission / reception device 11 via the ultrasonic sensor 10. The ultrasonic waveform at this time is as shown in FIG. 2, and since there is attenuation in the middle, the echo level (intensity level) of the reflected wave B appears lower than the transmitted wave A. On the other hand, the ultrasonic wave transmission / reception device 11 records the reflected wave received by the ultrasonic wave transmission / reception device 11 at a high speed, and determines whether or not the molten metal supply (material supply) is appropriate according to the process described in detail later. Is connected.

  Of course, the ultrasonic sensor 10 may be installed on the fixed mold 3 side instead of the movable mold 4 side. The ultrasonic sensor 10 may be installed at any location and in any number, but it is desirable to install at least one at the site corresponding to the final coagulation zone. Further, as this ultrasonic sensor, one having an ultrasonic transmitting element and an ultrasonic receiving element independently may be used. In this case, the ultrasonic transmitting element and the ultrasonic receiving element are adjacent to each other by a molding metal. Attach to mold 1.

  By the way, as shown in FIG. 3, the reflected wave B of the ultrasonic wave described above is a reflected wave (hereinafter referred to as a first wave) reflected from the molding surface 4a on the ultrasonic wave incident side (here, the movable mold 4 side). B1 and a reflected wave (hereinafter referred to as a second reflected wave) B2 reflected from the molding surface 3a on the opposite side (here, fixed mold 3) of the ultrasonic wave. In this case, the intensity level of the second reflected wave B2 changes with the progress of solidification of the molten metal M filled in the cavity 5. This material replenishment detection method pays attention to the change in the intensity level of the second reflected wave B2, and tries to grasp the suitability of the molten metal replenishment from the change in the intensity level. Hereinafter, the material replenishment detection method according to the present invention will be specifically described with reference to FIGS.

  At the start of die casting, the ultrasonic transmission / reception device 11 is activated in advance, and ultrasonic waves are incident from the ultrasonic sensor 10 into the cavity 5 of the molding die 1. Casting is started by advancing the plunger 9 after receiving a predetermined amount of the molten metal M in the injection sleeve 8, and the molten metal M is filled into the cavity 5 by the advancement of the plunger 9. Then, the molten metal replenishment determination device 12 starts recording the reflected wave B (FIGS. 2 and 3) received by the ultrasonic transmission / reception device 11, and at the same time the intensity level (echo of the second reflected wave B2 included in the reflected wave B) Level) monitoring.

  As shown in FIGS. 4 and 5, the intensity level of the second reflected wave B2 first increases with the progress of solidification (a), and after reaching the peak P1, gradually decreases (b). The first increase (a) in the intensity level of the second reflected wave B2 is due to an increase in ultrasonic transmittance due to the progress of solidification, and the subsequent decrease (b) is due to the solidification shrinkage due to the solidification shrinkage. This is because the adhesiveness between the solid phase S and the solid phase S (FIG. 1) has decreased.

  Here, when the replenishment of the molten metal M into the cavity 5 is sufficient, as shown in FIG. 4, the intensity level of the second reflected wave B2 increases again (c), and after reaching the peak P2, It decreases again (d). The second increase (c) in the intensity level of the second reflected wave B2 is due to the increase in the adhesion between the molding surface 3a and the solid phase S due to the replenishment of the molten metal. The subsequent decrease (d) This is because the adhesiveness is reduced due to proper coagulation shrinkage. On the other hand, when the molten metal replenishment is insufficient, as shown in FIG. 5, the intensity level of the second reflected wave B2 increases with the progress of solidification (a) and gradually decreases after reaching the peak P1 ( b) The phenomenon is the same as when the molten metal M is sufficiently replenished, but after that, the next peak P2 (FIG. 4) does not appear and the intensity level of the second reflected wave B2 remains lowered. Become. This indicates that since the molten metal replenishment is insufficient, the adhesion between the molding surface 3a and the solid phase S is lowered, and proceeds to the gap as it is.

  In the present embodiment, the molten metal replenishment determination device 12 monitors the intensity change pattern of the second reflected wave B2, and when two peaks P1 and P2 appear, the molten metal is sufficiently replenished. When only the peak P1 appears, it is determined that the molten metal supply is insufficient. That is, according to the material replenishment detection method, it is possible to accurately grasp whether or not material replenishment has been appropriately performed.

  The molding condition optimization method according to the present invention optimizes the molding conditions based on the detection result obtained by the material replenishment detection method described above, and is performed according to the flow shown in FIG. That is, first, in step S1, as shown in FIG. 1, the ultrasonic sensor 10 is attached to the molding die 1, and the ultrasonic sensor 10 and the ultrasonic transmission / reception device 11 are connected by wiring. Then, simultaneously with the completion of the filling of the molten metal M into the cavity 5 of the molding die 1, monitoring of the second reflected wave B2 by the molten metal replenishment determining device 12 is started (S2). The molten metal replenishment determination device 12 determines (determines) whether or not the molten metal is replenished by monitoring (see FIG. 4 and FIG. 5) of the second reflected wave B2, and when it is determined in step S3 that the molten metal has been properly replenished. The current molding conditions are maintained as they are (S4).

  On the other hand, if it is determined in step S3 that the molten metal replenishment is inappropriate (or not), the process proceeds to step S5, and the molding conditions are corrected (changed) so that the molten metal replenishment is optimized. In this case, the molding conditions may be changed by changing the shape of the gate width, gate position, cooling system, or the like, or by changing the filling conditions such as injection pressure (molding pressure), injection speed, molding temperature, etc. Of these, it is desirable to make these changes because the gate width, molding pressure, and molding temperature have a great influence on the molten metal supply. The changes in this case are an increase in gate width, an increase in molding pressure, and an increase in molding temperature. However, if the increase in molding pressure exceeds the full power of the injection device 2 (FIG. 1), large-scale equipment modification is required. In this case, the gate width is increased or the molding temperature is increased. desirable.

It is sectional drawing which shows the structure of the die-casting apparatus to which the material replenishment detection method which concerns on this invention is applied. It is a graph which shows the ultrasonic waveform at the time of entering an ultrasonic wave in a shaping die. 3 is a graph showing an enlarged waveform of a reflected wave in the ultrasonic waveform shown in FIG. 2. It is a graph which shows the behavior of the 2nd reflected wave monitored in this material replenishment detection method, and shows a result when molten metal replenishment is fully performed. FIG. 5 is a graph showing the behavior of the second reflected wave monitored in the material replenishment detection method, and showing the result when the molten metal replenishment is insufficient. It is a flowchart which shows the processing flow of the molding condition optimization method which concerns on this invention.

DESCRIPTION OF SYMBOLS 1 Molding die 2 Injection apparatus 3 Fixed mold 4 Movable mold 3a, 4a Molding surface 5 Cavity 10 Ultrasonic sensor 11 Ultrasonic transmission / reception apparatus 12 Molten metal supply determination apparatus M Molten metal

Claims (5)

  After filling the cavity of the molding die with the molten material, at least two of the intensity changes of the reflected wave reflected from the molding surface opposite to the incident side of the ultrasonic wave are incident on the cavity. A material replenishment detection method, comprising: determining that material replenishment has been appropriately performed when a peak is recognized.   The material replenishment detection method according to claim 1, wherein the molten material is a metal.   The material replenishment detection method according to claim 1, wherein the molten material is a resin. In the detection result by the material replenishment detection method of any one of Claims 1 thru | or 3, it is only one peak in the time change of the intensity level of the reflected wave reflected from the molding surface on the opposite side to the incident side of an ultrasonic wave. However, when the material supply is determined to be insufficient, the molding condition optimization method is characterized in that the die shape is changed to increase the gate width so that the shortage of material supply is resolved. In the detection result by the material replenishment detection method of any one of Claims 1 thru | or 3, it is only one peak in the time change of the intensity level of the reflected wave reflected from the molding surface on the opposite side to the incident side of an ultrasonic wave. They not appear only, when the material supply is determined to be insufficient, as the lack of material supply is eliminated, and performing a change of filling conditions for increasing the rise or molding temperature of the molding pressure molding Condition optimization method.

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