JP2006218483A - Injection device for molten material and injection control method for the injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection device for a molten material and an injection control method for the injection device for a molten material where the setting of injection control is simple and stable, and also, the injection control of high precision can be practiced. <P>SOLUTION: In the control method for an injection device 40 for a molten material B comprising: a heating cylinder 17 of storing the molten material B obtained by melting metallic materials A2, A3 at the front part; a nozzle 15 fitted to the tip of the heating cylinder 17 and connected to a die 10; and a plunger 20 of pressurizing the molten material B and injecting the same to the die 10 via the nozzle 15, a controller 31 for the injection device 40 memorizes and stores the tail position of the metallic material A2 in the heating cylinder 17 at the completion of the injection in the last molding cycle as an injection starting position value M0, and obtains the feeding distance D3 between the toe face P0 of a new metallic material A1 positioned at the rear part in the heating cylinder 17 for the injection of the following molding cycle and the injection starting position M0 by calculation based on the injection starting position value M0, so as to control the progressing velocity of the plunger 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molten material injection apparatus for injection-molding a metal material such as magnesium or aluminum, and an injection control method for the injection apparatus.

  Conventionally, as a molding method of metal materials such as magnesium and aluminum, a die casting method in which a molten metal is injected and filled into a mold under pressure to obtain a molded product, or a metal mold in the form of a pellet is melted by an injection screw. There is known a thixomold method for filling in a container. However, since the die casting method requires a melting furnace for melting the metal material in advance, there are problems such as an increase in cost and accumulation of oxide in the melting furnace. On the other hand, the thixomold method has problems that handling of the metal material in the form of pellets is complicated and that it is difficult to stably dissolve the metal material because an injection screw is used.

  A technique for solving such a problem is described in Patent Document 1. The technology of Patent Document 1 includes a material supply device that replenishes an injection cylinder one by one with a light metal material as a short rod material, an injection cylinder that melts in order from the short rod material that has been replenished in advance, and a heating device for the same. The present invention relates to an injection device of a light metal injection molding machine including a push rod member that injects a molten short rod material by progressively advancing the rod material, or an injection hydraulic piston rod. In this injection device, the push rod member is driven by a first drive device that is a hydraulic drive device and a second drive device that is an electric drive device, and the injection hydraulic piston rod has one injection hydraulic pressure. Driven by a cylinder.

  In the injection apparatus described in Patent Document 1, since the light metal material has a volume corresponding to several shots or more, that is, a length, the pushing amount of the light metal material reduced by consumption every time one shot is injected. In order to make it constant, the protruding amount of the push rod member is progressively adjusted for each shot by the second driving device.

  Therefore, according to the control method of the injection apparatus proposed in Patent Document 1, since the light metal material is supplied every plural molding cycles, the molding cycle time for each injection of the molding cycle becomes uneven and the injection As a result of the amount of light metal material supplied and stored in the cylinder changing at each injection of the molding cycle, the quality of the molded product varies.

  As an injection apparatus that solves the above problem, an injection apparatus shown in FIG. 1 of the present application has been proposed. The injection apparatus includes a heating cylinder that melts a metal material to form a molten material, a nozzle that is attached to a tip of the heating cylinder and is connected to a mold, and presses the molten material to pass the mold through the nozzle. A plunger that injects into the mold, and further, a material supply cylinder that supplies a metal material having a length corresponding to a molded product to the heating cylinder for each molding cycle, and between the heating cylinder and the material supply cylinder A die that is provided and cuts the outer periphery of the metal material, and a suction device that is provided in the vicinity of the die at the rear portion of the heating cylinder and deaerates the inside of the heating cylinder. Since this injection apparatus is configured as described above, the problems in the injection apparatus of Patent Document 1 are solved, but the following problems remain.

  That is, in order to make the volume of the metal material the same as the volume of the molded product, the length of the metal material is regulated to a predetermined allowable width. Since the metal material is injected at a constant stroke, the injection starts at the position where the new metal material supplied in the heating cylinder is supplied in the previous molding cycle and contacts the previous metal material located in the front. The position should not change from one molding cycle to more than a predetermined allowable dimension of the length of the metal material. Nevertheless, in practice, the injection start position varies within a range of several percent of the length of the metal material. Reasons for this include lack of precision in the length of the metal material, non-uniformity in the molten state of the molten material, fluctuations in the mold temperature, fluctuations in the driving force and forward speed of the plunger, etc. It is a result. In addition, it does not correspond to the volume of the molded product that molds the metal material in one molding cycle, but corresponds to the volume of the molded product that is molded in multiple molding cycles. There is also a case of injection. At that time, the injection start position changes in length corresponding to the volume of the molded product for each molding cycle.

  By the way, the setting of the plunger position for switching the forward speed of the plunger is performed based on the absolute position of the plunger (screw) as commonly used in a plastic injection molding machine or the like. When such a control method is applied to the injection control of a metal material whose injection start position varies, the plunger position for switching the forward speed of the plunger is interlocked with the fluctuation of the injection start position, resulting in extremely unstable injection control. . In order to avoid this problem, it is necessary to manually correct the position set value in accordance with the change in the injection start position, or to correct the position set value automatically by calculation processing, which is complicated and difficult. I was forced to set it.

Therefore, the position where the metal material newly supplied into the heating cylinder comes into contact with the metal material previously supplied into the heating cylinder is stored and stored as the injection start position value, and the plunger moves from the injection start position value. It has been proposed to switch and control the forward speed of the plunger based on the amount and the set value of the movement amount. However, through subsequent research and development, in order to increase the rising speed of injection, an empty chamber is provided between the metal material newly supplied into the heating cylinder and the metal material previously supplied into the heating cylinder. The metal material newly supplied into the heating cylinder collides with the metal material previously supplied into the heating cylinder and is injected. However, in this method, the “method of storing and storing the position where the metal material newly supplied into the heating cylinder abuts against the metal material previously supplied into the heating cylinder as the injection start position value” It is not applicable. The reason for this is that the metal material newly supplied into the heating cylinder collides with the metal material previously supplied into the heating cylinder at a very high speed, so detection of the contact point is delayed and accurate contact is made. This is because it is difficult to reliably determine the position.
Japanese Patent Laid-Open No. 2003-211260

  The present invention has been made in order to solve the above-described problems. An injection device for a molten material and an injection device for a molten material capable of performing injection control with ease and stable and highly accurate injection control. An object is to provide an injection control method.

  That is, the invention of claim 1 is a heating cylinder that stores a molten material obtained by melting a metal material in a front portion, a nozzle that is attached to a tip of the heating cylinder and connected to a mold, and the molten material is added. In a molten material injection apparatus having a plunger that presses and injects into the mold through the nozzle, the rear end position of the metal material in the heating cylinder at the end of injection of the previous molding cycle is an injection start position value. Storage unit for storing and storing as a new metal material positioned at the rear part in the heating cylinder for injection in the next molding cycle, or the air feed distance between the front end surface of the plunger and the injection start position. The present invention relates to an apparatus for injecting molten material, which includes a control device that calculates and calculates the advance speed of the plunger based on a start position value.

  According to a second aspect of the present invention, there is provided a heating cylinder for storing a molten material obtained by melting a metal material at a front portion, a nozzle attached to a tip of the heating cylinder and connected to a mold, and pressurizing the molten material. In the control method of the molten material injection device having a plunger that injects into the mold through the nozzle, the control device that controls the injection device of the molten material includes the heating at the end of injection of the previous molding cycle. The rear end position of the metal material in the cylinder is stored and stored as an injection start position value, and the new metal material or the front end surface of the plunger positioned at the rear end of the heating cylinder for injection in the next molding cycle and the injection The present invention relates to an injection control method for a molten material injection apparatus that calculates an air transport distance from a start position based on the injection start position value and controls a forward speed of the plunger.

  According to a third aspect of the present invention, in the second aspect, the value of the idling distance is calculated based on the injection start position value and is subtracted from a position setting group for switching the speed setting group of the plunger, or a moving amount setting is performed. The present invention relates to an injection control method of an injection device for molten material added to a group.

  The invention according to claim 1 is a heating cylinder for storing a molten material obtained by melting a metal material at a front portion, a nozzle attached to a tip of the heating cylinder and connected to a mold, and pressurizing the molten material. In a molten material injection apparatus having a plunger that injects into the mold through the nozzle, the rear end position of the metal material in the heating cylinder at the end of injection in a previous molding cycle is stored as an injection start position value. A new metal material that has a storage unit to be stored and is positioned at the rear part in the heating cylinder for injection in the next molding cycle, or an empty feed distance between the front end surface of the plunger and the injection start position is the injection start position Since it is a molten material injection device that calculates the value based on the value and controls the advance speed of the plunger, it is easy to set injection control, and a stable and highly accurate molten material injection device can be obtained.

  According to a second aspect of the present invention, there is provided a heating cylinder for storing a molten material obtained by melting a metal material at a front portion, a nozzle attached to a tip of the heating cylinder and connected to a mold, and pressurizing the molten material. In the control method of the molten material injection device having a plunger that injects into the mold through the nozzle, the control device that controls the injection device of the molten material includes the heating at the end of injection of the previous molding cycle. The rear end position of the metal material in the cylinder is stored and stored as an injection start position value, and the new metal material or the front end surface of the plunger positioned at the rear end of the heating cylinder for injection in the next molding cycle and the injection Since this is an injection control method of the molten material injection device that calculates the air transport distance from the start position based on the injection start position value and controls the advance speed of the plunger, the injection control setting is easy. In it it is possible to execute the injection control of the stable and highly accurate molten material.

  According to a third aspect of the present invention, in the second aspect, the value of the idling distance is calculated based on the injection start position value and is subtracted from a position setting group for switching the speed setting group of the plunger, or a moving amount setting is performed. Since it is added to the group, the setting operation of the switching position of the injection speed control is extremely easy and accurate.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a main part showing an injection apparatus for carrying out the present invention together with a block diagram of the control apparatus, and FIG. 2 is a cross-sectional view of a main part showing another injection apparatus for carrying out the present invention together with a block diagram of the control apparatus. FIG. 3 is a first flowchart showing the control method of the present invention, FIG. 4 is a second flowchart showing the control method of the present invention, and FIG. 5 is a graph showing the method of controlling the plunger forward speed according to the present invention.

  As shown in FIG. 1, the injection device 40 includes a mold 10 composed of a movable mold 11 and a fixed mold 12, a nozzle 15 inserted into an insertion port 13 of the fixed mold 12, and a die 18 on the front end surface of the nozzle 15. A heating cylinder 17 having a heater 16 on its outer peripheral surface as a rear end surface, and a material supply cylinder 19 that is provided coaxially with the center hole of the heating cylinder 17 and supplies a new metal material A1 made of magnesium, aluminum, or the like to the heating cylinder 17; Metal materials A2, A3 and metal materials for sealing a part of the previously supplied metal materials A2, A3 and a molten material B obtained by melting or semi-melting the previously supplied metal material to the front portion of the heating cylinder 17 A plunger 20 that presses and injects the molten material B via A1, a drive device 21 that drives the plunger 20 forward and backward, and a position detector that detects the position of the plunger 20 and transmits the signal to the control device 31. Consisting of 2. The drive device 21 is preferably a hydraulic device composed of a cylinder equipped with an accumulator that can easily obtain high speed and high pressure, but is an electro-mechanical device composed of a servo motor, a ball screw, or the like. Also good.

  The control device 31 includes a microprocessor, and includes a speed setting group 24, a movement amount setting group 25, a position setting group 26, an input / output unit 27, a display unit 28 including a liquid crystal panel, a storage unit 29, and the like. And an arithmetic processing unit 30 connected to all the groups and units. The control device 31 controls the temperature of the heater 16 of the heating cylinder 17, the drive device 21 and the mold clamping, as well as the sequence control for controlling the overall operation of the molding machine including not only the injection device 40 but also a mold clamping device (not shown). It comprehensively controls the speed, force, position, etc. of actuators such as devices.

  In the injection device 40, a cylindrical new metal material A1 having a volume required for one molding cycle is supplied from the material supply cylinder 19 into the heating cylinder 17 every molding cycle, and the position P0 of the front end surface of the metal material A1 is set to the plunger. The plunger 20 is positioned by the control device 31 so as to be a distance D1 from the 20 forward limit position D0. At this time, an empty chamber E having a distance D3 is formed between the position M0 of the rear end surface of the metal material A2 in the heating cylinder 17 and the position P0 of the front end surface of the metal material A1 at the end of injection of the previous molding cycle. Is done.

  Next, another embodiment of the injection device 41 different from the injection device 40 is shown in FIG. In FIG. 1 and FIG. 2, what attached | subjected the same code | symbol has the same member or the same function. What is different in the injection device 41 from that in the injection device 40 described above is a method of supplying a new metal material A1 into the heating cylinder 17 and an injection method. That is, in the injection device 41, the columnar new metal material A1 having a volume required for a plurality of molding cycles is made by the plunger 20 for each of the plurality of molding cycles so as to come into contact with the previously supplied metal material A2. It is supplied in advance from the supply cylinder 19 into the heating cylinder 17 prior to injection. In a molding cycle in which no new metal material A1 is supplied, the plunger 20 is temporarily retracted after the end of the injection, and the position of the front end surface of the plunger 20 is controlled to a position P0 from the advance limit position D0 of the plunger 20 to the distance D1. Positioned by the device 31. At this time, an empty chamber E having a distance D3 is formed between the position M0 of the rear end surface of the metal material A1 in the heating cylinder 17 and the position P0 of the front end surface of the plunger 20 at the end of injection of the previous molding cycle. The

  Next, the operation of the present invention will be described with reference to FIGS. In the flow chart of FIG. 3, in S <b> 1, a new metal material A <b> 1 put into the material supply cylinder 19 is pressed and advanced by the plunger 20 and pushed into the center hole of the heating cylinder 17 through the die 18. In the injection device 40 in FIG. 1, the metal material A1 is supplied into the heating cylinder 17 for each molding cycle. In the injection device 41 in FIG. 2, the metal material A1 is formed for each of a plurality of molding cycles in which the metal material A1 can be continuously molded. A1 is supplied into the heating cylinder 17. In the heating cylinder 17, there is a previous metal material A2 that has been pushed forward in the pre-molding cycle and is located in front. In the injection device 40 in FIG. 1, the rear end surface of the previous metal material A2 and the front end of the new metal material A1 are present. The new metal material A1 is positioned at the position P0 by the plunger 20 so that the empty chamber E is formed between the surfaces (S2). Also in the injection device 41 in FIG. 2, after the plunger 20 is advanced to bring the front end surface of the new metal material A1 into contact with the rear end surface of the previous metal material A2, the rear end surface of the new metal material A1 and the plunger 20 The plunger 20 is positioned at the position P0 so that the air feeding chamber E is formed between the front end surface of the nozzle 20 and the front end surface (S2).

  Next, as shown in FIG. 5, the drive device 21 is driven to start the plunger 20 moving forward. At this time, the forward speed of the plunger 20 requires a rise time of about several tens of milliseconds according to the output characteristics of the drive device 21 and the inertia of the drive device 21 and the plunger 20. Therefore, in the conventional configuration in which the plunger 20 directly pressurizes the molten material B to start injection (this does not have an empty feed chamber), this rise time is used to mold a high-quality molded product. Requested to be as short as possible. In particular, when the flow length of the molten material in the cavity C is long or the cross-sectional area in the flow direction is small, or when the molten material is a metal having a high thermal conductivity, the rise time of injection is determined as to whether molding is possible.

  In order to solve this problem, an empty room E is provided. While the plunger 20 is moving forward in the air feeding chamber E, the advance speed sufficiently rises to the set speed V1, and the metal material A1 or the plunger 20 is the metal material A2 (in the case of the injection device 40 in FIG. 1). Alternatively, by colliding with the metal material A1 (in the case of the injection device 41 in FIG. 2) at high speed, injection of the molten material B can be started at high speed regardless of the rise time of the forward speed of the drive device 21 and the plunger 20. (S3 (see FIG. 3)).

  As shown in FIG. 5, in the injection process, each set value Vn (here, V1, V2, V3) of the speed setting group 24 and each set value Vn of the speed setting group 24 are sequentially switched. It is executed based on a program set in advance by the set value Mn (here, M1, M2). That is, as shown in FIG. 3, the arithmetic processing unit 30 determines whether or not the movement amount of the plunger 20 from the injection start position value M0 exceeds the set values Mn of the movement amount setting group 25. (S4). As a result, when the movement amount from the injection start position value M0 does not exceed the setting values Mn of the movement amount setting group 25, the speed control using the current setting values of the speed setting group 24 is continued. When the movement amount of the plunger 20 from the injection start position value M0 exceeds each setting value Mn of the movement amount setting group 25, the forward speed of the plunger 20 is determined from among the setting values Vn of the speed setting group 24. The change is made by switching to the next set value Vn, which is the speed corresponding to each set value Mn in the movement amount setting group 25 (S5). For example, as understood from FIG. 5, when the movement amount of the plunger 20 reaches the movement amount setting value M1, the speed setting value is switched from V1 to V2. Similarly, when the movement amount of the plunger 20 reaches the movement amount setting value M2, the speed setting value is switched from V2 to V3. The same switching control is performed when the desired number of speed stages is larger. As described above, since the speed of the plunger 20 is switched based on the movement amount of the plunger 20 and its set value, high-precision injection control can be performed with simple and easy setting.

  Although the injection process control is executed as described above, in the present invention, since the empty feeding chamber E exists, the set value Mn of the movement amount setting group 25 should be set in consideration of the distance D3 of the empty feeding chamber E. It has to be very cumbersome and cumbersome. Therefore, control is performed as shown in FIG. That is, the amount of movement of the plunger 20 that moves forward is always detected by the position detector 22 and is taken into the control device 31 and processed. The movement amount of the plunger 20 is generally controlled by directly comparing and calculating with the set value Mn of the movement amount setting group 25. However, the setting of the movement amount of the plunger 20 used for calculation processing in the control of the injection process is performed. The value is not the set value Mn of the moving amount setting group 25 but the moving amount setting group 25 based on the injection start position value M0 detected at the position of the plunger 20 at the position of the rear end surface of the metal material A1 at the end of injection in the previous molding cycle. The set value Mn is subtracted and corresponds to the position setting group 26 based on the forward limit position D0 of the plunger 20. Each set value of the position setting group 26 is Pn, here, P1 and P2. For this reason, the movement amount setting group 25 is operated by effectively using the software of a general-purpose control device configured to control the injection process based on the position setting group 26 without drastically changing. Can be requested.

  Specific arithmetic processing will be described with reference to FIGS. As shown in FIG. 4, when the injection process is completed (S6), the control device 31 detects the position of the rear end surface of the metal material A1 as the position of the plunger 20 with the position detector 22, and starts the injection in the storage unit 29. The position value M0 is stored and stored (S7). And the control apparatus 31 calculates | requires each value of the setting value Pn of the position setting group 26 by subtracting each value of the setting value Mn of the movement amount setting group 25 from the injection start position value M0 (S8). Further, the distance D2 of the injection start position value M0 is subtracted from the set value D1 of the position P0 of the plunger 20 positioned before the injection at the rear part of the heating cylinder 17 to obtain the idle feeding distance D3 (S9). Next, the set value Pn of the position setting group 26 is calculated for the next molding cycle by subtracting the flying distance D3 obtained in S9 from each value of the setting value Pn of the position setting group 26 determined in S8. The value is updated (S10).

  As described above, since the injection start position value M0 varies for each molding cycle, and the set value Mn of the movement amount setting group 25 does not vary for each molding cycle, the position setting group 26 as the movement amount setting value is used for the molding cycle. It fluctuates every time. Therefore, the position setting group 26 as the set value of the movement amount is rewritten for each molding cycle when the injection start position is stored and stored as the injection start position value M0 in the storage unit 29 of the control device 31. By doing so, the set value of the moving amount of the plunger 20 is replaced from the moving amount setting group 25 to the position setting group 26, and the moving amount of the plunger 20 can be set regardless of the presence of the flying distance D3. It is possible to control the injection by programming a substantial amount of the molten material B.

  Through the injection process, the molten material B is injected and filled into the cavity C through the gate 14 of the mold 10. The molten material B injected and filled into the cavity C is cooled and solidified to form a molded product. The molded product is taken out from the mold 10 in which the movable mold 11 is opened apart from the fixed mold 12, and the molding cycle is completed.

  In addition, this invention includes what can be implemented in the aspect which added various change, correction, improvement, etc. based on the knowledge of those skilled in the art. Further, it goes without saying that any of the embodiments to which the above-mentioned changes are added is included in the scope of the present invention without departing from the gist of the present invention. For example, in this embodiment, the setting value of the movement amount of the plunger 20 as the injection speed switching position is configured to be replaced from the movement amount setting group 25 to the position setting group 26. However, the movement is performed without providing the position setting group 26. It is also possible to perform the injection speed switching control by directly calculating the injection start position value M0 only by setting the amount setting group 25. In this case, the air transport distance D3 is added to the movement amount setting group 25 and controlled.

It is principal part sectional drawing which shows the injection apparatus which implements this invention with the block diagram of the control apparatus. It is principal part sectional drawing which shows the other injection apparatus which implements this invention with the block diagram of the control apparatus. It is a 1st flowchart which shows the control method of this invention. It is a 2nd flowchart which shows the control method of this invention. 3 is a graph illustrating a method for controlling the forward speed of a plunger according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold 15 Nozzle 17 Heating cylinder 20 Plunger 24 Speed setting group 25 Movement amount setting group 26 Position setting group 29 Memory | storage part 31 Control apparatus 40,41 Injection apparatus A1 New metal material A2 Previous metal material B Molten material C Cavity D3 Empty Feed distance E Empty room M0 Injection start position value

Claims (3)

A heating cylinder for storing a molten material obtained by melting a metal material in a front portion, a nozzle attached to a tip of the heating cylinder and connected to a mold, and pressurizing the molten material to the mold through the nozzle In a molten material injection device having a plunger for injection into a mold,
It has a storage unit for storing and storing the rear end position of the metal material in the heating cylinder at the end of injection of the previous molding cycle as an injection start position value, and the rear part in the heating cylinder for injection of the next molding cycle A controller for controlling a forward speed of the plunger by calculating a blank feeding distance between the new metal material positioned at the front or the front end surface of the plunger and the injection start position based on the injection start position value. A molten material injection device. A heating cylinder for storing a molten material obtained by melting a metal material in a front portion, a nozzle attached to a tip of the heating cylinder and connected to a mold, and pressurizing the molten material to the mold through the nozzle In a method of controlling a molten material injection device having a plunger for injection into a mold,
The control device that controls the injection device of the molten material stores and stores the rear end position of the metal material in the heating cylinder at the end of injection of the previous molding cycle as an injection start position value, and performs the next molding cycle A new metal material positioned at the rear part in the heating cylinder for injection of the heating cylinder or an air feed distance between the front end surface of the plunger and the injection start position is calculated based on the injection start position value, and the plunger moves forward. An injection control method for an apparatus for injecting molten material, characterized by controlling a speed. The melting according to claim 2, wherein the value of the air transport distance is calculated based on the injection start position value and is subtracted from a position setting group for switching a speed setting group of the plunger or added to a movement amount setting group. Injection control method of material injection device.

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