KR900006297B1 - Method and apparatus for controlling a machine having a movable member and a fixed member - Google Patents

Abstract

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Description

Method and apparatus for controlling a machine having a movable member and a fixed member

1 is a conceptual diagram showing an injection molding machine and a control device to which the present invention can be applied;

2 is a partial cross-sectional side view showing the detailed structure of the injection molding machine shown in FIG.

3 is a graphical representation of the operating characteristics of a nozzle useful for demonstrating the principles of the invention;

4 is a black diagram showing the control system shown in FIG.

5 is a flow chart illustrating the operation of the control system shown in FIG.

6a is a flow chart for use in a special case,

Figure 6b is a flow chart used in the general case.

* Explanation of symbols for main parts of the drawings

Sf: Current position signal Sn: Target distance signal

Si: Distance signal Vn: Deceleration information

Vd: Generated signal when Sn = Sf 30C: Movable mold

30B: Fixed mold I: Screw

5: injection nozzle 7: second driving means

13: first driving means 14: position detecting means

15 controller 51 Si signal generator

54: Subtractor 55: Comparator

56: deceleration information generator

The present invention relates to a method and apparatus for controlling a movable member of a machine having a movable and stationary member, and more particularly, in a case where the movable member is advanced toward the stationary member in an injection molding machine or a die casting machine or the injection nozzle is fixed. The present invention relates to a method and an apparatus for contacting without impact at high speed when advancing toward the back side. The present invention will be described by taking an injection molding machine as an example.

2 is a basic configuration of an injection molding machine to which the present invention can be applied. In FIG. 2, the electric motors 7 and 13 are attached to the case 10 so that the motor 7 injects, charges and meters the resin, and the motor 13 fixes the mold or advances the nozzle. Gears 41 and 42 are mounted on shaft 13A of motor 13, while gears 43 and 44 are mounted on shaft 7A of motor 7. The driving force of the gears 41 to 44 is interrupted by the operation of the clutch mechanisms 45 and 46 attached to the ends of the shafts 7A and 13A, respectively. The motion transmission shafts 47A and 48A are journaled by the casing 40 where the driving force is interrupted by the operation of the clutch mechanisms 47 and 48. The gears 49 and 50 are mounted on the shaft 47A, and the gears 51 and 52 are mounted on the shaft 48A.

The drive shaft 30A which moves the movable mold 30C (FIG. 1) which comprises the metal mold | die 30 which has an internal cavity is stored by the casing 40. As shown in FIG. Inside the casing 40, gears 32 to 34 on which driving force is interrupted by a clutch mechanism 901 at one end of the shaft 30A are mounted to the shaft 30A. In order to open and close the mold by reciprocating the movable mold 30C along the stationary mold 30B, the operating shaft 38 which slides the mold supporting member 39 along the guide rods 38A and 38B is geared ( A gear 36 for driving through 37 is mounted to the drive shaft 30 in the left casing 35. The casing 40 also has a shaft 1A connected to the screw 1, and a gear 53 is attached to the shaft 1A. Gear 55 is mounted to an axis supported by gear 53 via bearing 54. The above-mentioned injection molding machine operates as follows. Advancing the movable mold 30C toward the fixed mold 30B, increasing the pressure for increasing the mold fixed pressure, advancing the nozzle to the fixed mold 30B, injecting molten resin into the mold by injection, and controlling the proper amount supply of the resin. , A series of operations such as cooling to cure the resin, retracting the nozzle 5 toward the casing 40, reducing the pressure and opening the mold, and ejecting the molded product from the mold. 2 shows the initial state of the injection molding machine. The motor 13 is operated to drive the drive shaft 30A through the gears 41 and 33 and the gears sandwiched therebetween, not shown, to perform mold clamping and pressure increase. Then, the shaft 38 is driven through the gears 36 and 37 to advance the movable mold.

When the movable mold stops and the mold is fixed, the clutch 901 is released to stop the transmission of the driving force from the gear 33 to the gear 36. At the same time, the clutch mechanisms 45 and 47 are connected to rotate only the shaft 47A to move the casing 40 toward the mold, whereby the nozzle 5 is advanced toward the stationary mold 30B. The nozzle 5 retreats by reversing the rotation of the motor 13 while the seed mold is opened by rotating the motor in the opposite direction to the mold fixing case to retract the movable mold 30C. As the nozzle 5 advances toward the stationary mold 30B, the screw 1 rotates to transfer the resin 4 contained in the hopper 3 to the injection cylinder 2. In the meantime, the resin is mixed and kneaded so that it can be heated and molded by a heater not shown. The screw 1 is pushed back in the direction of the arrow N because of the pressure of the resin 6 contained in the cylinder 2. The injection molding machine is configured to prevent air from being sucked into the cylinder 2 and the nozzle 5 through the hopper 3 for accurate metering of the resin. When the movable mold 30C fixed to the support member 39 and the fixed mold 30B are fixed together by the speed control of the motor 13, the movable mold 30C advances to the fixed mold 30B. Then, as the movable mold 30C approaches the fixed mold 30B sufficiently, the control is switched to the pressure control state. After being engaged, the two molds are brought into contact with each other at a predetermined pressure. If the time or position at which the speed control is switched to the pressure control is not specified, the speed and pressure change discontinuously when the speed control is switched to the pressure control.

Moreover, when the stationary mold approaches for biting, when the speed of the movable mold 30C is too large, both molds may be damaged by a large impact force because they are made of hard metal. The vibration generated by the impact force extends the time interval at which both molds are brought into full contact under a predetermined pressure. Incomplete contact may result when a braking force is applied before the vibration is zero. If the speed at the time of contact is not constant, the mold holding force is changed. Similarly, when the nozzle 5 proceeds to the mold 30, the speed of the motor 13 is controlled by the speed controller 15 and the control is performed when the movable mold 30C approaches the stationary mold 30B sufficiently. Switch to control. However, in such a control, when the speed control is switched to the pressure control, the nozzle 5 and the mold 30 are changed when the speed or pressure fluctuates or the contact speed is high because the time or position at which the speed control is switched to the pressure control is not constant. ) Is damaged by an impact, or a long time is required before the nozzle and the mold contact each other under a predetermined pressure due to vibration caused by the contact. On the other hand, when the braking force is applied to the nozzle 5 before the damping of the vibration is completely completed, no reliable contact is made. Moreover, if the speed of the nozzle is not constant, the pressure on the mold may fluctuate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a machine and a member having a stationary member and a movable member to control the movable member and the stationary member firmly without impact and to move the movable member at high speed toward the stationary opening. To provide.

One feature of the present invention is to move the movable member toward the stationary member at a controlled speed, and to operate at a time determined by the relationship between the expected distance between the deceleration start and stop of the movable member and the actual speed of the movable member. Providing deceleration information to the driving means of the member, and reducing the moving speed of the movable member to zero at the time of contact with the stationary member of the movable member in accordance with the deceleration information provided. It is to provide a control method of a machine having a fixed member and a movable member.

A further aspect of the present invention is a control device for a machine comprising a fixed member and a drive member of a movable member approaching and disengaging during operation of the machine, wherein the control device is configured to have a current position of the movable member and a movable member at actual zero. A device for generating a signal S1 indicative of the distance between the points coming into contact with the stationary member at a speed, a position sensing device driven by the drive to produce a signal Sf indicative of the current position of the movable member; When a device for generating a signal Sn indicating a target distance, a device for obtaining a signal difference Sn-Sf, and a signal S1 and a signal difference Sn-Sf are compared, and then the two signals coincide And a deceleration information generator in response to the signal Vd for sending the deceleration information Vn to the driving means. A preferred embodiment of the present invention shown in FIGS. 1 and 2 will be described.

It is assumed that mold fixing position information Sc, injection mold nozzle contact position information Sn, and screw information Si are continuously applied to the controller 15. Initially, the speed signal Vc calculated to move the movable mold 30C toward the stationary mold from the normal speed to the B direction at the time of fixing the mold is rotated by the gear 41, the gear 55, the gear. It is transmitted to the shaft 38 via the drive shaft 30A, the gear shaft 36, and the gear 37, so that the movable mold 30C moves forward. During the advance, the position sensor 14 periodically searches for the axis position of the shaft 38 to supply the controller 15 with a feedback signal Sf indicating the position S of the movable mold 30C. . Therefore, the controller 15 detects the speed and position of the movable mold 30C.

After fixing the mold 30 as described above, when the nozzle 5 advances toward the stationary mold 30B, the speed signal Vn calculated to advance the nozzle 5 at the normal speed is gear 41. And a gear 55 are supplied to the motor for driving the ballscrew 11. In addition, the nozzle 5 mounted on the support member 10 is driven by the ball screw 11 through the ball nut 12 and is advanced toward the stationary mold 30B. In the meantime, the position sensor 14 connected to the motor 13 periodically sends a feedback signal Sf indicating the position of the ball nut 12, that is, the position of the nozzle 5, to the controller 15. Thus, the controller 15 detects the speed and position of the nozzle 5.

When the front end of the nozzle 5 advances toward the stationary mold 30B, the resin is injected into the mold. At this time, the screw rotation signal Ri calculated by the screw position information Si is sent to the motors M2 and 7, and the motor 7 rotates the screw 1. Resin (4) sent from the hopper (3) to the cylinder (2) is cut and kneaded by the screw (1) and thus fired resin (6) fills the cylinder (2) and is injected into the mold. Due to the pressure of the resin 6 contained in the cylinder 2, the screw 1 retreats in the N direction. At this time, outside air is prevented from being sucked into the cylinder 2, and the correct amount of resin is measured. The rotation speed sensor 8 connected to the motor 7 detects the rotation speed n of the screw 1 in order to send a screw rotation speed feedback signal Rf to the controller 15.

As described above, according to the present invention, the movable mold 30C or the nozzle 5 is advanced at a high speed, and then the movable mold 30C or the nozzle is decelerated to zero when or immediately before or in contact with the fixed mold 30B. Since the speed control is performed such that the 30C or the nozzle 5 is in contact with the fixed mold 30B at low and low pressure, the impact at the time of contact becomes small and complete contact is made within a short time. The operation of advancing the movable mold 30C or the nozzle 5 toward the stationary mold 30B is performed by simply connecting the common motors M1 and 13 to the clutch 901. In addition, since the control method of the above operation is the same, the control method for advancing the nozzle 5 toward the mold will be described in detail.

)가 된다.3 is a graph showing the operating characteristics of four useful nozzles 5 illustrating the principles of the present invention. Here, the abscissa axis represents time t, and the ordinate axis represents the speed of the nozzle 5. The nozzle speed at time t ₀ is V ₀ . Although the velocity information shown by the characteristic curve LL0 starts in the time zone, the actual speed of the nozzle 5 is shown by the characteristic curve LL1 in which the velocity becomes zero at time t ₃ . In Figure 3 U decelerates. wc stands for speed loop gain. The principle of the present invention will be explained by the operating characteristic of FIG. More specifically, the nozzle speed is controlled to have a value V ₀ and the speed and position are periodically checked as described above. The difference between the position where the nozzle 5 is in contact with the mold 30 and the current position will be equal to the distance required for the nozzle speed to decelerate the current speed that becomes zero when the nozzle contacts the mold 30. At that time, deceleration is started. More specifically, if the velocity information of the characteristic LL0 is issued at time t ₀ , the nozzle speed becomes zero at time t ₂ as long as the nozzle 5 moves according to this information. However, since the nozzle 5 has inertia, the actual speed is shown by the characteristic LL1 so that the nozzle 5 can come into contact with the mold 30 when the speed is reduced to zero at time t ₃ . The slope at the zero speed of the characteristic LL1 is equal to the slope of the deceleration U. Speed (V ₁₎ at time t ₁ is the same as the inverse of the specific (LL2) and constant speed (V ₀₎ speed loop gain (wc) at the point (C) meeting between a straight line that indicates the speed (V1 ) Is (

)

Thus, time t _{3 corresponds} to (V ₀ / u + 1 / wc).

Assuming that the distance required to reduce the speed when the nozzle 5 is in contact with the mold 30 to zero is equal to the area S1 surrounded by the points A, B, C, and D, the following equation is established.

However, since the actual movement of the nozzle 5 is represented by the characteristic curve LL1, the distance between the position at t ₀ and the position at which the velocity is almost zero is the area S ₂ surrounded by the straight lines AB, AD, and the curve LL1. ). If the area surrounded by the straight lines DC, BC and the curve LL1 is S ₃ , the following equation is obtained.

S ₂ = S ₁ -S ₃ ... (2)

Therefore, when the distance before the nozzle 5 is in contact with the mold 30 becomes equal to the distance corresponding to the area S ₁ , the deceleration information is used to reduce the nozzle speed to zero before contacting the mold 30 with the nozzle. It is always possible. The time until the nozzle speed reaches zero is determined by the speed loop gain (wc). If a larger speed gain (wc) is selected, it is always possible to set the nozzle speed to zero at a point closer to the mold 30. Do. In other words, when the deceleration information is issued such that the nozzle speed becomes zero at a point close to the mold 30, the nozzle 5 may come into contact with the mold 30 before the nozzle speed becomes 0, Thus, an impact may occur. Therefore, it is a feature of the present invention to reduce the nozzle speed when the nozzle contacts the mold to be substantially zero. After the nozzle speed reaches zero, the nozzle can stably contact the mold 30 without any vibration or impact by the control switching from the speed control to the pressure control. The control method of advancing of the movable member 30C with respect to the fixing member 30B at the time of metal mold | die fixing is the same as what was demonstrated above.

The motor may be either a DC or AC motor and may be moved along the guide member using an electric motor instead of moving the moving mold and nozzle using ball screws and ball nuts.

As described above, according to the control method of the injection molding machine according to the present invention, the nozzle and the movable mold 30C when the movable mold approaches to contact the fixed mold or when the nozzle comes close to contact the mold 30. ) Can be reduced to zero, so that the impact or vibration at the time of contact can be effectively prevented. Moreover, the adhesive force is also constant regardless of the moving mold or the speed of the nozzle, thus reducing the production time and producing a homogeneous product.

Although the present invention has been described above in connection with an injection molding machine, the present invention can be applied to a diecasting machine other than an injection molding machine in that molten metal poured into a cylinder is cast into a mold by a piston.

More broadly, the present invention can be applied to any machine having members in which the movable member advances or retracts from the fixed member at a relatively high speed.

The control device according to the present invention will be described. 4 is a block diagram showing details of the control system used in FIGS. In FIG. 4, block 51 represents a generator that generates the signal S1 shown in equation (1). The signal S1 is obtained by the computer continuously calculating the area S1 at each detection cycle or pulse. The block 14 corresponds to the position sensor 14 shown in FIG. 1, which indicates the current position of the movable mold and generates a signal Sf which is used as a feedback signal. Block 53 is a target distance Sn setter. In the case shown in FIG. 3, the target distance Sn coincides with the distance between position A and the time t ₃ or B at which the movable mold or the speed of the nozzle is reduced to zero. Signals Sf and Sn are sent to subtractor 54 to obtain a difference signal Sn-Sf representing the remaining distance that the movable mold has to move. The signals S1 and Sn-Sf are applied to the comparator 55 which sends the signal Vd to the deceleration information generator 56 when the compared signals are identical to send the deceleration signal Vn to the motor 13. All.

In the flowchart shown in FIG. 5, the deceleration distance S1 in step 101 is calculated with a computer by equation (1). That is, the distance S1 required for the deceleration operation is determined by the speed and the deceleration parameter of the movable member. Next, in step 102, the position feedback signal Sf is recorded, and in step 103, the remaining distance Sn-Sf is determined as described above. In step 104 a check is made to determine if S1 = Sn-Sf. If the result of the check is NO, the program is sent to step 102 to execute step 102, step 103 again, and if YES, the motor 13 is decelerated until the speed reaches zero in step 105. . In the special case of FIG. 6A, the movable member speed V and its increment (ΔV) are set in step 110. In step 111, S1 is calculated using V and ΔV, and in step 112 a target distance Sn is set. In step 113, the equation P = Sn-Sf is calculated, and in step 114 the feedback signal Sf is set. Then, in step 115, it is checked whether P = Sf.

If the result is NO, the program is sent to step 114 and if the check result is YES, deceleration information is issued to the motor 13 in step 116. The flowchart shown in FIG. 6B is for use in the general case, and operations in steps 120, 121, 122, 123 and 125 are respectively shown in steps 110, shown in FIG. 6A, Same as the operation of 111, 112, 114, and 116. The flowchart of FIG. 6B differs from that of FIG. 6A in that a check in step 124 is performed to see if S1 is equal to (Sn-Sf). If the check result is NO, the program is sent to step 120 to perform steps 120, 121, 122, and 123 again. If YES, deceleration information is issued in step 125.

Claims (9)

A control method of a machine consisting of a movable member and a fixed member which are in contact with and separated from each other during operation, the method comprising: moving the movable member at a controlled speed toward the fixed member, the actual speed of the movable member, and By sending deceleration information to the drive unit of the movable member at a time determined by the relationship between the expected movement distance to start and stop of the deceleration, the moving member speed decreases to zero when the movable member and the stationary member contact each other. The control method of the machine, characterized in that the step to be made. The control method according to claim 1, wherein the movable member and the fixed member are respectively composed of a movable mold and a fixed mold of an injection molding machine. The control method according to claim 1, wherein the movable member and the fixed member are each composed of a molten resin injection nozzle and a mold of the injection molding machine. 2. A position according to claim 1, wherein a difference between a position at which the movable member is in contact with the fixed member and an actual position of the movable member is decelerated from an actual speed of the movable member to be in contact with the movable member and the fixed member. And the deceleration information is issued when the speed is equal to the distance required to zero. The control method according to claim 2, further comprising the step of switching the control of the injection molding machine from the speed control to the pressure control when the speed of the movable member becomes zero. The die casting machine of claim 1, wherein the machine comprises a die, a casting nozzle filled with molten metal, an apparatus for accessing the casting nozzle to the mold, and an apparatus for casting the molten metal on the mold. Control method of the machine. A device for controlling a machine consisting of a movable member and a fixed member and a driving device of the movable member, which are in contact with and separated from each other during operation, wherein the current position of the movable member and the movable member are at almost zero speed with the fixed member. A device for generating a signal (S1) indicating the distance between the contacted position, a position sensing device driven by the drive device for generating a signal (Sf) indicating the current position of the movable member, a signal indicating a target distance ( Sn), a device that obtains a signal difference Sn-Sf, and compares the signal S1 and the signal difference Sn-Sf to generate a signal Vd if the two compared signals are approximately equal. And a deceleration information generating device for generating deceleration information (Vn) to the drive device in accordance with the comparison device and the signal (Vd). 8. The control apparatus of claim 7, wherein the signal is used as a feedback signal of the apparatus. 8. The apparatus of claim 7, wherein the apparatus comprises a movable mold, a fixed mold, an injection nozzle for injecting plasticized resin into a cavity formed by engaging the molds, a screw installed in a nozzle for forming a plastic resin, the nozzle and the movable mold. A first driving device to drive relatively, a second driving device to rotate the screw, a rotation speed sensor driven by the second driving device to generate a signal indicating the rotational speed of the screw, and the signal to the controller of the device Control device of a machine comprising an injection molding machine consisting of transmitting devices.

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