JP4313258B2 - How to set the reference value for mold closing position - Google Patents

Description

  The present invention relates to a mold closing position reference value setting method for setting a mold closing position reference value touched by a movable mold and a fixed mold when a mold is closed by a toggle mold clamping device.

  Conventionally, a toggle type mold clamping device for clamping a mold provided in an injection molding machine is known from Japanese Patent Publication No. 6-61806. As disclosed in the same publication, the toggle type mold clamping device connects between a movable plate supporting the movable die and a crosshead moving forward and backward by a drive unit supported by the pressure receiving plate by a toggle link mechanism. It has a function of increasing the pressure force and transmitting it to the movable platen, and a predetermined mold clamping force is generated based on the extension of the tie bar when the toggle link mechanism is almost extended. In the mold clamping operation, the high-speed mold closing is normally performed from the mold opening position, and the process shifts to the low-speed low-pressure mold closing when the low-speed low-pressure switching position set in advance is reached. This low-speed and low-pressure mold closing becomes a mold protection section, and a molded product or the like that has not been normally discharged is detected as a foreign object. When the preset high pressure switching position is reached, the high pressure mold clamping is performed by shifting to the high pressure mold clamping.

  By the way, the toggle type mold clamping device is different from the direct pressure type mold clamping device because of its mold clamping principle, even when the mold and the tie bar are slightly expanded and contracted due to disturbance factors such as the heating temperature of the mold and the outside temperature. The mold clamping force fluctuates greatly, and a problem that cannot be ignored such as a deterioration in quality at the time of molding a precision molded product occurs. For example, even when the normal mold clamping force (target value) is set to 400 [kN] before the mold is heated, after the mold is heated, the mold is thermally expanded to 500 Increase to about [kN]. After the mold is heated, heat is transferred from the mold to the tie bar, so that the tie bar is thermally expanded and the mold clamping force is gradually reduced. The thermal expansion of the mold causes an increase in mold clamping force, and the thermal expansion of the tie bar causes a decrease in mold clamping force.

As described above, in the toggle type mold clamping device, disturbance factors such as the mold heating temperature and the outside air temperature are factors that cannot be ignored for accurately maintaining the mold clamping force. The mold thickness or clamping force during the molding operation is detected by the type or magnetic scale and the position detector (die thickness detection means) installed on the movable die plate, and a correction value for the set value of this detection value A mold clamping force control method in a toggle type mold clamping apparatus in which the mold clamping force is kept constant by feeding back to the mold pressure adjusting means is also known from Japanese Patent Application Laid-Open No. 62-32020.
JP 6-61806 JP-A-62-232020

  By the way, when the mold clamping force is kept constant as in the conventional mold clamping force control method in the toggle type mold clamping apparatus described above, a set value (reference) to be compared with the detected value of the mold thickness (position of the movable die plate). It is assumed that the (value) is accurately set in advance. If the reference value (set value) is not accurately set and includes an error, even if correction is performed later, the error will be included in all correction results. It is extremely important to set accurate reference values.

  On the other hand, such setting of the reference value of the mold closing position is normally performed in a preparation stage before starting production by mold replacement. That is, when the mold is exchanged, first, the position setting of the pressure platen is automatically executed by the automatic mold thickness adjusting process, and then the temperature raising process for the mold is performed by the mold temperature adjusting process. In this case, since the mold expands and the clamping force increases as described above, after the temperature increasing process, the operator confirms that the state is stable, executes the automatic mold thickness adjustment process again, and The mold closing position is detected in stages, and the detection result is set as a reference value.

  However, at this stage, automatic mold thickness adjustment is performed again due to the fact that the mold thickness adjustment has already been performed due to the mold change and that this stage is also the stage immediately before production is possible. The process is often omitted. In this case, the reference value is detected during the subsequent automatic mold clamping force correction process, but the reference value is detected in a state where a mold clamping force larger than the normal mold clamping force is generated. As a result, even if automatic clamping force correction processing is performed during production operation, correction processing is performed based on a clamping force that is larger than the normal clamping force. There was a problem that could not be set.

  An object of the present invention is to provide a mold closing position reference value setting method that solves the problems in the background art.

  In order to solve the above-described problem, the reference value setting method for the mold closing position according to the present invention closes the mold when the movable mold Cm and the fixed mold Cc touch when the mold C is closed by the toggle mold clamping device Mc. In the reference value setting method for setting the reference value Ds of the position Xc, if an automatic mold thickness adjustment step S01 for automatically setting the position of the pressure receiving plate 2 with respect to the mold C is executed, and the automatic mold thickness adjustment step S01 is completed. The amount of movement of the crosshead 5 in the movable platen 4 or the toggle type clamping device Mc accompanying the closing of the mold C, and the mold before performing the mold temperature adjusting step S05 for heating the mold C and raising the temperature. This variation rate is obtained by sequentially detecting the variation amount of the load torque T accompanying the closing of C and obtaining the variation rate (including the variation amount) ΔT of the load torque T with respect to the constant movement amount ΔX of the movable platen 4 or the crosshead 5. ΔT is a preset setting rate T The automatic closing position detecting step S03 for automatically detecting the position when the position reaches the mold closing position Xc is continuously executed, and the die closing position Xc detected by the automatic closing position detecting step S03 is used as the reference value Ds. It is characterized by being set.

  In this case, according to a preferred aspect of the invention, in the automatic mold thickness adjusting step S01, the pressure receiving plate 2 is advanced at a first speed Vh that is a high speed from the retracted position with the toggle link mechanism 3 extended, and the pressure receiving plate 2 1 reaches the mold closing position Xc, the first step F1 is moved backward by a predetermined distance Ls, and after the first step F1, the pressure receiving plate 2 is moved forward at a low speed Vs, and the mold closing position Xc is reached. Is reached, the toggle link mechanism 3 is bent to open the mold by a predetermined distance Lr, and thereafter, the pressure receiving platen 2 is advanced by a distance Lc corresponding to a clamping allowance for obtaining a target mold clamping force. Step F2 can be provided. In the first step F1, when the pressure receiving plate 2 reaches the mold closing position Xc, the toggle link mechanism 3 is bent to open the mold by a predetermined distance Lp, and thereafter, the pressure receiving plate 2 is moved to the predetermined distance. After retreating by Ls, the toggle link mechanism 3 can be extended.

  According to the method for setting the reference value of the mold closing position Xc according to the present invention by such a method, the following remarkable effects are obtained.

  (1) The automatic mold thickness adjusting step S01 is executed. When the automatic mold thickness adjusting step S01 is completed, the automatic closing position detecting step S03 is continuously executed. Thus, the normal reference value Ds can always be reliably set, and an accurate mold clamping force can be set stably.

  (2) Since the distributed automatic processing processes in the production preparation stage can be combined into a series of continuous processes, it is possible to simplify the setup work required from mold replacement to production start. And it can contribute to the improvement of work efficiency.

  (3) The automatic closing position detection step S03 is performed by moving the cross head 5 in the movable platen 4 or the toggle type mold clamping device Mc when the mold C is closed, and the fluctuation amount of the load torque T when the mold C is closed. Are sequentially detected, and the fluctuation rate (including the fluctuation amount) ΔT of the load torque T with respect to the constant movement amount ΔX of the movable platen 4 or the crosshead 5 is obtained, so that the fluctuation rate ΔT reaches a preset setting rate Ts. Since the current position is automatically detected as the mold closing position Xc, accurate and stable detection can be performed as compared with the case where the load torque T itself (absolute value) is detected by comparison with a threshold value.

  (4) According to a preferred embodiment, in the automatic mold thickness adjusting step S01, the pressure receiving plate 2 is advanced at a first speed Vh that is a high speed from the retracted position with the toggle link mechanism 3 extended, and the pressure receiving plate 2 is moved to the mold. When the closed position Xc is reached, the first step F1 is moved backward by a predetermined distance Ls, and after the first step F1, the pressure receiving plate 2 is moved forward at a low speed Vs to reach the mold closed position Xc. Then, the toggle link mechanism 3 is bent to open the mold by a predetermined distance Lr, and then the second step F2 is performed to advance the pressure receiving platen 2 by a distance Lc corresponding to a clamping allowance for obtaining a target mold clamping force. If provided, the time required for mold thickness adjustment can be shortened to reduce the number of work steps, improve the production efficiency, and ensure sufficient accuracy and stability.

  (5) According to a preferred embodiment, the first step F1 is carried out by bending the toggle link mechanism 3 when the pressure receiving plate 2 reaches the mold closing position Xc and opening the mold by a predetermined distance Lp. If the toggle link mechanism 3 is extended after the board 2 is retracted by a predetermined distance Ls, even if a geared motor having a small output torque is used as a drive source for moving the pressure receiving board 2, It is possible to avoid the problem of being unable to move backward due to so-called tightening when reaching the mold closing position Xc, and it is possible to reliably shift to the next operation.

  Next, the best embodiment according to the present invention will be given and described in detail with reference to the drawings.

  First, the structure of the toggle type mold clamping device Mc that can implement the reference value setting method for the mold closing position Xc according to the present embodiment will be described with reference to FIGS.

  In FIG. 2, the injection molding machine indicated by M includes a toggle type mold clamping device Mc and an injection device Mi. The toggle type mold clamping device Mc includes a fixed platen 11 and a pressure platen 2 that are spaced apart from each other. The fixed platen 11 is fixed on a machine base (not shown), and the pressure platen 2 moves forward and backward on the machine table. Supported as possible. Further, four tie bars 12 are installed between the fixed platen 11 and the pressure receiving platen 2. In this case, the front ends of the tie bars 12 are fixed to the fixed platen 11 and the rear ends of the tie bars 12 are inserted into the pressure receiving plate 2.

  On the other hand, the movable platen 4 is slidably loaded on the tie bars 12. The movable platen 4 supports the movable mold Cm, the fixed platen 11 supports the fixed mold Cc, and the movable mold Cm and the fixed mold Cc constitute a mold C. Further, a toggle link mechanism 3 is disposed between the pressure receiving plate 2 and the movable platen 4. The toggle link mechanism 3 includes a pair of first links 3a and 3a pivotally supported on the pressure receiving plate 2, a pair of output links 3c and 3c pivotally supported on the movable platen 4, the first links 3a and 3a and the output links 3c, A pair of second links 3 b and 3 b coupled to the support shaft of 3 c is provided, and the second links 3 b and 3 b are pivotally supported on the cross head 5.

  A mold clamping drive unit 14 is disposed between the pressure receiving plate 2 and the cross head 5. The mold clamping drive unit 14 includes a ball screw unit 15 that is rotatably supported by the pressure receiving plate 2, and a ball nut unit 16 that is screwed into the ball screw unit 15 and provided integrally with the cross head 5. A ball screw mechanism 17 is provided, and a rotation drive mechanism unit 18 that rotationally drives the ball screw unit 15 is provided. The rotational drive mechanism 18 includes a mold clamping servo motor 19, a rotary encoder 20 attached to the servo motor 19 for detecting the rotational speed of the servo motor 19, and a drive gear 21 attached to the shaft of the servo motor 19. A driven gear 22 attached to the ball screw portion 15 and a timing belt 23 spanned between the drive gear 21 and the driven gear 22 are provided.

  Accordingly, when the servo motor 19 is operated, the drive gear 21 is rotated, and the rotation of the drive gear 21 is transmitted to the driven gear 22 via the timing belt 23, and the ball screw portion 15 is rotated to thereby rotate the ball nut. The part 16 moves forward and backward. As a result, the cross head 5 integrated with the ball nut portion 16 moves forward and backward, the toggle link mechanism 3 bends or extends, and the movable platen 4 moves forward and backward in the mold opening direction (retracting direction) or the mold closing direction (forward moving direction). To do.

  On the other hand, a die thickness adjusting device 25 is attached to the pressure receiving platen 2. The mold thickness adjusting device 25 includes screw mechanisms 28 formed by forming screw portions 26 on the rear end sides of the four tie bars 12 and screwing adjustment nuts 27 to the respective screw portions 26. In this case, the adjusting nuts 27 also serve as stoppers for the pressure receiving plate 2. Accordingly, when the adjustment nuts 27 are rotated, the pressure receiving platen 2 can be moved forward and backward because the adjustment nuts 27 are displaced relative to the screw portions 26.

  Further, a geared motor 30 serving as a driving source for moving the pressure receiving plate 2 is attached to the side surface of the pressure receiving plate 2. The geared motor 30 is a drive motor for adjusting the mold thickness. The geared motor 30 includes a motor main body 31. The motor main body 31 includes a motor unit using an induction motor provided in the second half and a reduction gear mechanism that receives rotation of the motor unit by being provided in the first half. An output shaft 32 that outputs the rotation of the reduction gear mechanism projects from the front end surface of the motor main body 31. Further, a motor shaft in the motor unit protrudes from the rear end surface of the motor main body unit 31, and a motor brake unit 33 that locks or unlocks the position of the motor shaft and a rotary encoder unit 34 that detects the number of rotations of the motor shaft. Is attached. The rotary encoder unit 34 can detect an absolute position based on the number of encoder pulses generated with respect to a reference position using an incremental encoder. In addition, since the rotary encoder part 34 and the motor brake part 33 are assembled | attached integrally with the motor main-body part 31, it can contribute to the whole size reduction compactness similarly to the servomotor with an encoder.

  3 and 4, a drive gear 35 is attached to the front end side of the output shaft 32, and small gears 36 are integrally attached to the adjustment nuts 27, respectively. In this case, the adjustment nuts 27 and the small gears 36 are positioned on the same axis. Further, large gears 37 that mesh with the small gears 36 and the drive gear 35 are provided. The large gear 37 is formed in a ring shape, and a rail portion provided along the inner peripheral surface is supported by four support rollers 38 attached to the pressure receiving plate 2. That is, the small gears 36 are arranged at the four corners of the square, and the large gears 37 are arranged at positions surrounded by the small gears 36, so that the small gears 36 mesh with the large gears 37 at the same time. To do.

  Therefore, when the geared motor 30 is operated, the large gear 37 is rotated by the rotation of the drive gear 35, and the small gears 36 are simultaneously rotated by the rotation of the large gear 37. Then, the adjustment nuts 27 that rotate integrally with the small gears 36 move forward and backward along the screw portions 26 of the tie bars 12, so that the pressure receiving plate 2 also moves forward and backward, and its front-rear direction position is adjusted. . Reference numeral 40 denotes a molding machine controller, which connects the mold clamping servo motor 19, the rotary encoder 20, the geared motor 30, the motor brake unit 33, and the rotary encoder unit 34.

  On the other hand, FIG. 5 shows a servo circuit 41 which is a part of the molding machine controller 40. The servo circuit 41 includes deviation calculation units 42 and 43, adders 44 and 45, a position loop gain setting unit 46, a feed forward gain setting unit 47, a speed limiter 48, a speed converter (differentiator) 49, and a speed loop gain setting unit. 50, a torque limiter 51, a driver 52, a disturbance monitoring unit 53, and an acceleration converter (differentiator) 54, and a servo control system (servo circuit 41) is constituted by the system shown in FIG. The above-described mold clamping servo motor 19 is connected to the output side of the driver 52, and the rotary encoder 20 attached to the servo motor 19 is connected to the speed converter 49 and the inverting input section of the deviation calculating section 42, respectively. Connecting. Further, the non-inverting input unit of the deviation calculating unit 42 is connected to a sequence controller (not shown).

  Further, in the figure, Pt is a signal capturing terminal used for detecting the load torque T accompanying the closing of the mold C, and Pv is a signal capturing terminal used for detecting the speed V of the movable platen 4 when the mold C is closed. , Pa is a signal capturing terminal used for detecting the acceleration A of the movable platen 4 when the mold C is closed, Pe is a signal capturing terminal used for detecting the estimated torque E generated by the disturbance due to the closing of the mold C, Px indicates a signal take-in terminal used for detecting the position deviation Ex of the movable platen 4 when the mold C is closed. In addition, operation | movement (function) of each part is demonstrated by the whole operation | movement of toggle type mold clamping apparatus Mc mentioned later.

  FIG. 6 shows a display screen 57 of a display attached to a side panel or the like provided in the injection molding machine M. The display screen 57 is provided with a touch panel, and various settings and the like can be performed using the touch panel. A display screen 57 shown in FIG. 6 is a mold opening / closing setting screen, and has a graphic display portion 57g for graphically displaying a variation curve W of the load torque T, a numerical display portion 61 related to the mold protection end position, and a mold. A numerical display unit 62 related to the closing position, a numerical display unit 63 related to the mold closing position reference, and a numerical display unit 64 related to the end position of the mold closing monitor are provided.

  In this case, in the graphic display portion 57g, the horizontal axis (X axis) is the position [mm] of the crosshead 5, and the vertical axis (Y axis) is the load torque T [%]. The load torque T [%] is displayed with the maximum torque being 100 [%]. Thereby, the magnitude of the load torque T corresponding to the position [mm] of the crosshead 5 is graphically displayed on the graphic display portion 57g as the fluctuation curve W. Further, the graphic display portion 57g includes a cursor 61c (pink) indicating the end position Xe of the mold protection section Zd1, a cursor 62c (red) indicating the detection value Dd of the mold closing position Xc, and a reference for the mold closing position Xc. A cursor 63c (blue) indicating the value Ds and a cursor 64c (green) indicating the end position Xf of the mold closing monitor section serving as the second mold protection section Zd2 are displayed by color-coded vertical lines. By displaying the cursors 61c, 62c, 63c, and 64c color-coded corresponding to each item, the operator can easily and accurately (reliably) know the position corresponding to each item.

  On the other hand, the numerical display unit 61 displays the numerical value of the end position Xe (see FIG. 7) of the mold protection section Zd1 according to the position of the crosshead 4 and the position of the crosshead 5 on the movable platen 4. The numerical display unit 62x has a second display unit 61x that displays a numerical value in terms of a position, and a numerical display unit 62 includes a first display unit 62h that numerically displays the detection value Dd of the mold closing position Xc according to the position of the crosshead 5. A second display portion 62x that displays the numerical value by converting the position of the crosshead 5 into the position of the movable platen 4 is provided. In addition, the numerical display unit 63 converts the reference value Ds of the mold closing position Xc into a numerical value based on the position of the crosshead 5 and converts the position of the crosshead 5 into the position of the movable platen 4. The numerical display unit 64 has a second display part 63x for displaying numerical values, and a display part 64h for displaying numerically the end position Xf of the mold closing monitor section to be the second mold protection section Zd2 according to the position of the crosshead 5. And an ON key 64s for setting the end position Xf. Further, the upper positions of the respective numerical display portions 61, 62, 63 and 64 are “mold protection end position”, “mold closure position”, “mold closure position reference” and “mold closure monitor”, respectively. In addition to displaying the items, the color frame portions 61k (pink), 62k (red), 63k (blue), and 64k (green) are displayed around each item. The colors 61k (pink), 62k (red), 63k (blue), and 64k (green) are the colors of the cursors 61c (pink), 62c (red), 63c (blue), and 64c (green). It corresponds to the color. Thereby, the operator can easily know which item each cursor 61c, 62c, 63c and 64c corresponds to. The position of the crosshead 5 can be easily converted to the position of the movable platen 4 by using a known conversion formula. FIG. 8 shows a display mode when the range of the scale on the horizontal axis (X axis) and the vertical axis (Y axis) in the graphic display unit 57g is changed.

  Next, the operation (function) of the toggle type mold clamping device Mc including the reference value setting method for the mold closing position Xc according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a flowchart showing the entire processing procedure of the reference value setting method for the mold closing position Xc. First, the molding machine controller 40 automatically detects an automatic mold thickness adjustment mode for automatically setting (adjusting) the position of the pressure receiving plate 2 with respect to the mold C supported by the toggle type mold clamping device Mc and the mold closing position Xc. It has an automatic closing position detection mode. As shown in FIG. 1, when the automatic mold thickness adjustment mode (automatic mold thickness adjustment process) is executed, the automatic mold position adjustment mode (automatic closing position detection process) is performed upon completion of the automatic mold thickness adjustment mode. ) Is then automatically executed (step F0). Therefore, a sequence program for executing each mode is set in the molding machine controller 40, and sequence control is performed according to this sequence program and various processes are executed. The mold closing position Xc is a position where the movable mold Cm and the fixed mold Cc touch.

  Hereinafter, a specific processing procedure of the reference value setting method will be described. Assume that the mold C is exchanged and the automatic mold thickness adjustment mode is selected. FIG. 9 is a flowchart showing a processing procedure in the automatic mold thickness adjustment mode.

  By selecting the automatic mold thickness adjustment mode, a series of automatic mold thickness adjustment processes are executed (step S01). First, the operation of the geared motor 30 is controlled to retract the pressure receiving platen 2 to the retracted position (step S1). The reverse speed at this time is a normal speed based on the power supply frequency of 60 Hz. At the retracted position, the mold clamping servomotor 30 is controlled to be in the extended state (the extended state) of the toggle link mechanism 3 (step S2). In this case, the retracted position is set to the last retracted position, but a predetermined gap may be generated between the movable mold Cm and the fixed mold Cc with the toggle link mechanism 3 extended. Need not be.

  Next, the operation of the geared motor 30 is controlled, and the pressure receiving platen 2 is moved forward (step S3). The forward speed in this case is the first speed Vh that is high. The first speed Vh is a normal speed based on the power supply frequency 60 Hz for driving the geared motor 30. When the mold closing position Xc is reached, the pressure receiving platen 2 is stopped (steps S4 and S5). Therefore, the pressure receiving plate 2 moves at a normal speed (first speed Vh) at a high speed over a distance Lf from the retracted position that is a relatively long distance section to the mold closing position Xc. The mold closing position Xc is a position where the movable mold Cm and the fixed mold Cc touch as described above, and can be detected by the following method, for example. That is, the load torque fluctuation amount associated with the closing of the mold C is sequentially detected, and the fluctuation rate of the load torque with respect to the constant movement amount is sequentially obtained, so that the position when the fluctuation rate reaches a preset setting rate. Is detected as the mold closing position Xc. This detection method will be described in detail later.

  Next, the mold clamping servomotor 19 is controlled to bend the toggle link mechanism 3, whereby the movable platen 4 is retracted by a predetermined distance Lp to slightly open the mold (step S6). This mold opening is for the following reason. As described above, when the pressure receiving plate 2 is moved forward at the first speed Vh that is a high speed and the movable mold Cm and the fixed mold Cc are touched at the mold closing position Xc, so-called tightening occurs due to inertia during forward movement. Thereafter, even if the geared motor 30 is controlled to retract the pressure receiving platen 2, it cannot move. In particular, since the momentum and acceleration are proportional, the amount of tightening (the amount of movement until stopping) is proportional to the square of the speed, and when moving at the first speed Vh that is high, the amount of tightening is ignored. When the geared motor 30 having a small output torque is used as a drive source for moving the pressure receiving platen 2, the tightening cannot be released. Therefore, the mold clamping servo motor 19 is controlled and the toggle link mechanism 3 is bent to release the tightening. Therefore, the distance Lp for retracting the movable platen 4 is sufficient, and can be set to about several [mm], preferably around 4 [mm]. Thereby, when reaching the mold closing position Xc and stopping the pressure receiving platen 2, it is possible to avoid the problem of being unable to move backward due to tightening, and it is possible to reliably shift to the next operation.

  Next, the geared motor 30 is controlled to retract the pressure receiving plate 2 by a predetermined distance Ls (step S7). In this case, the first speed Vh described above can be used as the reverse speed. As described above, when advanced at the first speed Vh, which is a high speed, tightening occurs at the mold closing position Xc. This tightening amount is, for example, an error when setting (adjusting) the mold clamping force. As a result, the reproducibility of the mold clamping force becomes worse, and in particular, a low mold clamping force cannot be set. Therefore, the pressure receiving platen 2 that has reached the mold closing position Xc at the first speed Vh is once retracted, and then re-advanced at a very low speed. Therefore, the predetermined distance Ls may be a small distance that can realize this processing, and can be set to about several [mm], preferably around 2 [mm].

  When the pressure receiving platen 2 has been retracted by a predetermined distance Ls, the mold clamping servo motor 19 is controlled to extend the toggle link mechanism 3 (step S8). Thereby, the movable board 4 moves forward by the same distance as the distance Lp described above. Therefore, a gap having the same distance as the above-described distance Ls is generated between the movable mold Cm and the fixed mold Cc. The above is the first step F1. After the first step F1, the following second step F2 is performed.

  In the second step F2, first, the geared motor 30 is controlled to advance the pressure receiving platen 2 (step S9). The forward speed in this case is the second speed Vs that is low. The second speed Vs is set to a fine speed of about 10 to 30% of the first speed Vh. That is, since the first speed Vh is set based on the power supply frequency of 60 Hz for driving the geared motor 30, this power supply frequency is set low, specifically about 6 to 18 Hz, preferably about 10 Hz. In this way, by setting the second speed Vs to 10 to 30% of the first speed Vh, the time for the mold thickness adjustment work is shortened and the accuracy and stability with respect to the set clamping force are optimized. It is possible to make it compatible with the state. Note that by setting the second speed Vs by lowering the power supply frequency for driving the geared motor 30, speed switching (speed change) can be easily performed even when the geared motor 30 is used.

  When the mold closing position Xc is reached, the pressure receiving platen 2 is stopped (steps S10 and S11). Therefore, the pressure platen 2 moves forward at a slow speed over a distance Ls that is a relatively short distance section. In this case, since the distance Ls is small, the moving time is short even at a very low speed. Further, since the vehicle moves forward at a slow speed, the impact when reaching the mold closing position Xc is reduced and a stable operation is ensured, and in particular, the tightening amount described above can be greatly reduced. That is, the second speed Vs is set to 10 to 30% of the first speed Vh, and the tightening amount is proportional to the square of the speed, and can be reduced to about 1/100 to 1/10. . As a result, the variation in the mold clamping force set by the mold thickness adjustment is about 2 to 5% when performed only at the first speed Vh, whereas the second variation as in the present embodiment. By carrying out by adding the speed Vs, it was able to be improved to about 0.1-0.2 [%].

  Next, the mold clamping servo motor 19 is controlled to bend the toggle link mechanism 3 so that the movable platen 4 is retracted by a predetermined distance Lr to slightly open the mold (step S12). In this case, the distance Lr is a movement for setting a fastening allowance described later, and a distance that can secure at least the fastening allowance is selected. Specifically, it can be set to about 4 mm, which is about the same as the distance Lp described above. Then, the geared motor 30 is controlled, and the pressure receiving platen 2 is advanced by a distance Lc corresponding to a clamping allowance for obtaining a target mold clamping force (step S13). The advance speed in this case uses the second speed Vs described above. By using the second speed Vs, it is possible to set the tightening allowance for which accuracy is required with high accuracy. Since the relationship between the distance when the movable platen 4 is advanced from the mold closing position Xc and the mold clamping force is set in advance, the distance Lc corresponding to the clamping allowance for obtaining the target mold clamping force is selected. be able to. Thereafter, the mold clamping servomotor 19 is controlled and the toggle link mechanism 3 is extended to perform high-pressure mold clamping (step S14). Thereby, the automatic mold thickness adjustment mode (automatic mold thickness adjustment process) is completed (step S02).

  The automatic mold thickness adjustment mode based on such a method includes a first step F1 that advances the pressure receiving plate 2 at a first speed Vh that is a high speed from the retracted position, and a slight distance that is set after the first step F1. Unlike the conventional method in which the rear platen is moved in a state where the mold is in contact with the rear platen because the second process F2 is performed to advance at the second speed Vs that is low by Ls, the time required for mold thickness adjustment is shortened. Reduction of work man-hours and improvement of production efficiency can be achieved. In addition, since the mold thickness can be adjusted by substantially the same operation as that in the original mold clamping process, it is possible to eliminate room for errors due to the difference in operation, and to ensure sufficient accuracy and stability. . Moreover, even when a geared motor 30 or the like having a small output torque is used as the drive source for moving the pressure receiving plate 2, the problem of being unable to move backward due to so-called tightening when reaching the mold closing position Xc can be avoided. It is possible to reliably shift to the next operation.

  On the other hand, upon completion of the automatic mold thickness adjustment process, the process immediately shifts to the automatic closing position detection mode, and the automatic closing position detection process is executed (step S03). In the automatic closing position detection mode, the movement amount (displacement amount) of the crosshead 5 accompanying the closing of the mold C and the variation amount of the physical quantity accompanying the closing of the mold C are sequentially detected, and the constant movement amount ΔX of the crosshead 5 is detected. By sequentially obtaining the variation rate ΔT of the physical quantity with respect to, the position when the variation rate ΔT reaches a preset set rate Ts is detected as the mold closing position Xc.

  In this case, the fluctuation rate ΔT may be a fluctuation amount. That is, the fluctuation rate ΔT may be obtained as a fluctuation amount ΔT corresponding to the constant movement amount ΔX, or may be a fluctuation rate obtained from ΔT / ΔX. Moreover, the load torque T is used as a physical quantity. A signal related to the load torque T is obtained from the signal take-in terminal Pt described above, and a signal obtained from the signal take-in terminal Pt is given to the molding machine controller 40. Further, the amount of movement of the crosshead 5 is detected by using an encoder pulse of the rotary encoder 20 that detects the rotation speed of the servo motor 19.

  On the other hand, a setting rate Ts is set in the molding machine controller 40. As shown in FIG. 8, this set rate Ts is obtained when the variation rate (increase rate) ΔT of the load torque T with respect to the constant movement amount ΔX of the crosshead 5 accompanying the closing of the mold C reaches the set rate Ts. Is used as a mold closing position Xc. Therefore, the magnitude of the setting rate Ts can be set as appropriate through experiments and adjustments. For example, since the load torque T is displayed as a percentage with the maximum torque being 100 [%], the constant movement amount ΔX of the crosshead 5 is set to several millimeters, and the rate of increase (increase amount) ΔT of the load torque T at this time Is obtained, the set rate Ts for the rate of increase ΔT can be set to around 1%.

  Hereinafter, a specific processing procedure in the automatic closing position detection mode will be described with reference to the flowchart shown in FIG. Now, it is assumed that the mold C is in the mold open position (fully open position). Therefore, the crosshead 5 in the toggle link mechanism 3 is in the mold opening position Xa shown in FIG. When the mold clamping operation is started, the mold clamping servo motor 19 is operated, the cross head 5 moves forward, and the movable platen 4 moves forward from the mold opening position in the mold closing direction. At this time, first, the high speed mold closing is performed in which the movable platen 4 moves forward at high speed.

  In this case, the servo circuit 41 performs speed control and position control for the movable platen 4 (crosshead 5). That is, a position command value is given from the sequence controller to the deviation calculation unit 42 of the servo circuit 41 and compared with a position detection value obtained based on the encoder pulse of the rotary encoder 20. Thereby, since the position deviation Ex is obtained from the deviation calculating section 42, position feedback control is performed based on the position deviation Ex.

  The position deviation Ex is compensated by the position loop gain setting unit 46 and applied to the input unit of the adder 44, and the position command value is compensated by the feedforward gain setting unit 47 and input to the adder 44. To be granted. Then, the output of the adder 44 is given to the non-inverting input unit of the deviation calculating unit 43 via the speed limiter 48. On the other hand, the position detection value is differentiated by the speed conversion unit 49 and converted into a speed (speed detection value) V, and the speed V is given to the inverting input unit of the deviation calculation unit 43. Thereby, since the speed deviation is obtained from the deviation calculating unit 43, the feedback control of the speed is performed based on this speed deviation. In this case, the speed V is limited by the speed limiter 48.

  Further, the speed deviation is compensated by the speed loop gain setting unit 50 and applied to the input unit of the adder 45. On the other hand, the velocity V is differentiated by the acceleration conversion unit 54 and converted into an acceleration (acceleration detection value) A, and the acceleration A is given to the input unit of the disturbance monitoring unit 53. The disturbance monitoring unit 53 monitors the acceleration A and, for example, outputs an estimated torque (torque value) E that speeds recovery when the acceleration A abnormally changes due to some cause (disturbance). The estimated torque E is given as a correction value to the input unit of the adder 45. As a result, a torque command (command value) is obtained from the adder 45, and this torque command is given to the driver 52 via the torque limiter 51. Thereby, the servo motor 19 is driven and controlled, and the position control and speed control for the movable platen 4 (cross head 5) are performed. The torque command output from the torque limiter 51 is fed back to the input unit of the disturbance monitoring unit 53.

  On the other hand, when the movable platen 4 moves forward in the mold closing direction and the crosshead 5 reaches a preset low-speed / low-pressure switching point Xb, the process shifts to low-speed / low-pressure mold closing (step S21). In this low-speed and low-pressure mold closing, as shown in FIG. 7, a mold protection process such as foreign object detection is performed in the mold protection zone Zd1 set in the preceding stage. That is, in the mold protection section Zd1, the magnitude of the load torque T is monitored, and if a preset threshold value is exceeded, it is determined that there is a foreign object and abnormal processing such as mold opening control is performed.

  As shown in FIG. 8 (FIG. 6), the end position Xe of the mold protection section Zd1 is set in advance by a numerical value display unit 61 that also serves as a setting function. Since the end position Xe is set in a preliminary manner before detecting the normal mold closing position Xc (reference value Ds), it is set with some margin before the assumed mold closing position. can do. In setting, a numerical value is set in the first display portion 61h according to the position of the crosshead 5. In this case, for example, a known setting method of inputting numerical values by touching the first display unit 61h and displaying a numeric key window can be used. By setting the end position Xe, a cursor 61c corresponding to the set end position Xe is displayed on the graphic display portion 57g. Since the color (pink) of the cursor 61c matches the color (pink) of the color frame portion 61k displayed on the numerical value display portion 61 as described above, the operator uses the cursor 61c to determine the end position Xe. Can be easily and accurately known, and the end position Xe corresponding to the mold protection section Zd1 can be easily and reliably known.

  Then, when the mold protection section Zd1 is completed, the mold closing position Xc for the mold C is detected. That is, an increase rate monitoring process for monitoring the magnitude of the increase rate ΔT for detecting the mold closing position Xc is performed (step SP). In FIG. 7, Zd2 represents a second mold protection section that serves as a mold closing monitor section, but has not yet been set at this point. In the increase rate monitoring process, first, the molding machine controller 40 detects the position of the crosshead 5 (step S22). The position of the crosshead 5 is detected by using an encoder pulse of a rotary encoder 20 that detects the number of rotations of the mold clamping servomotor 19. In this case, the rotary encoder 20 is an incremental encoder and detects the absolute position based on the number of encoder pulses generated with respect to the reference position. By using such a rotary encoder 20, a separate position detecting means for detecting the position of the crosshead 5 becomes unnecessary. As described above, by using the displacement amount (movement amount) of the crosshead 5 having a relatively large movement amount with respect to the movement amount of the movable platen 4, it is possible to detect the mold closing position Xc with high accuracy. it can. As a result, it is possible to accurately detect the fluctuation amount of the mold clamping force, which will be described later, and to correct the mold clamping force accurately.

  Further, the molding machine controller 40 sequentially takes in the load torque T, for example, at a sampling period of every 500 [μsec], and obtains a moving average of N times by averaging processing (steps S23 and S24). As a result, the obtained load torque T is graphically displayed as a variation curve W on the graphic display unit 57g as shown in FIGS. 6 and 8, corresponding to the detected position of the crosshead 5.

  Further, by obtaining the displacement amount (movement amount) of the crosshead 5 and the fluctuation amount of the load torque T, an increase amount (increase rate) ΔT of the load torque T with respect to the constant movement amount ΔX of the crosshead 5 is obtained (step S25). ). In this case, for example, when the constant movement amount ΔX of the crosshead 5 is set to several millimeters, a corresponding increase amount (increase rate) ΔT [%] of the load torque T is obtained. Then, it is monitored whether or not the increase rate ΔT has reached a preset set rate Ts. If the increase rate ΔT has reached the set rate Ts, the position of the crosshead 5 at that time is determined as the mold closing position Xc. (Steps S26 and S27). The taken-in mold closing position Xc is set as the reference value Ds (step S28).

  As described above, since the automatic closing position detection step S03 (automatic closing position detection mode) is subsequently executed upon completion of the automatic mold thickness adjustment step S01, the setting of the reference value Ds is omitted due to an error such as an operator forgetting. Thus, the regular reference value Ds can always be reliably set, and the accurate mold clamping force can be set stably. In addition, since the distributed automatic processing processes in the production preparation stage can be combined into a series of continuous processes, it is possible to simplify the setup work required from mold exchange to production start. It can contribute to improvement of work efficiency.

  On the other hand, the reference value Ds is displayed on the graphic display portion 57g on the display screen 57 by the cursor 63c. Since the color (blue) of the cursor 63c matches the color (blue) of the color frame portion 63k displayed on the numerical value display portion 63 as described above, the operator uses the cursor 63c to measure the reference value Ds. As well as the reference value Ds of the mold closing position Xc can be easily and reliably known. The reference value Ds is numerically displayed on the first display portion 63h, converted to the position of the movable platen 4, and displayed on the second display portion 63x. The above description is a basic aspect of the closed position detection mode, and the actual reference value Ds (and the detected value Dd) is obtained by executing the closed position detection mode a plurality of times and obtaining a plurality of closed position reference values Ds. Obtain from the average.

  Furthermore, when the reference value Ds is set, the operator displays a numerical value that also serves as a setting function for the end position Xf of the mold closing monitor that becomes the second mold protection zone Zd2 with reference to the reference value Ds. Manual setting is performed using the unit 64 (step S29). That is, the operator displays the end position Xf of the second mold protection zone Zd2 with reference to the cursor 63c related to the reference value Ds displayed on the graphic display unit 57g and the numerical display of the first display unit 63h. A numerical value is set in the section 64h. In this case, the end position Xf is set according to the position of the crosshead 5. The end position Xf is set in consideration of the thickness of the molded product. For example, when the thickness of the molded product is 0.1 [mm], the end position Xf can be set between the mold closing position Xc and the front 0.1 [mm]. In the present embodiment, since the end position Xf is set by the position of the crosshead 5 having a relatively large displacement amount with respect to the moving amount of the movable platen 4, a thin sheet having a thickness of about 0.1 [mm]. The end position Xf can be set easily and with high accuracy even in the case of the molded product.

  When the end position Xf is set on the display unit 64h, the end position Xf of the mold closing monitor section serving as the second mold protection section Zd2 is moved to the graphic display section 57g by touching the ON key 64s. 64c. Since the color (green) of the cursor 64c matches the color (green) of the color frame portion 64k displayed on the mold closing monitor setting unit 64 as described above, the operator uses the cursor 64c to move the end position. The degree of Xf can be easily and accurately known, and the end position Xf of the mold closing monitor section serving as the second mold protection section Zd2 can be surely known. Thus, the automatic closing position detection mode (automatic closing position detection step) ends (step S04).

  By adopting the automatic closing position detection mode by such a method, accurate and stable detection can be performed as compared with the case where the physical quantity itself (absolute value) is detected by comparison with a threshold value. In addition, since a mold thickness detecting means such as a scale or a position detector for directly detecting the thickness of the mold C is not required, the cost can be reduced by reducing the number of parts, and the configuration around the mold C is particularly complicated. Can be eliminated. In addition, by using the displacement amount (movement amount) of the crosshead 5 in the toggle type mold clamping device Mc having a relatively large movement amount with respect to the movement amount of the movable platen 4, high accuracy with respect to the mold closing position Xc is obtained. Detection can be performed.

  On the other hand, by the end of the automatic closing position detection mode, a mold temperature adjustment process is performed in which the mold C is heated and heated (step S05). Therefore, the automatic closing position detecting step is executed before the mold temperature adjusting step, unlike the conventional case. When the mold temperature adjustment process is completed, the production operation is performed by moving to the production stage (step S06). During production operation, the automatic closing position detection mode is automatically executed when a preset closing position detection time or the number of closing position detection shots is reached. In particular, at the start of production, the automatic closing position detection mode is first executed. In this case, the reference value Ds of the mold closing position Xc is set by executing the automatic closing position detection mode before the mold temperature adjusting process is performed. The mold clamping force increases due to thermal expansion of the mold, and the mold clamping force fluctuates gradually due to thermal expansion of the tie bars 12... Automatic correction processing for the tightening force is performed. It should be noted that the execution interval of the automatic closing position detection mode during production operation may be performed every time it is shot, or may be performed every certain shot (or certain time), and the degree of fluctuation of the clamping force in the actual machine may be determined. It can be set in consideration.

  Hereinafter, a processing procedure in the automatic closing position detection mode at the start of production (during production operation) will be described. Now, it is assumed that the mold C is in the mold open position (fully open position). Therefore, the crosshead 5 in the toggle link mechanism 3 is in the mold opening position Xa shown in FIG. When the mold clamping operation is started, the mold clamping servo motor 19 is operated, and the movable platen 4 moves forward from the mold opening position to the mold closing direction. At this time, the movable platen 4 is first subjected to high-speed mold closing that moves forward at high speed. When the movable platen 4 moves forward in the mold closing direction and the crosshead 5 reaches the preset low-speed / low-pressure switching point Xb, the low-pressure / low-pressure mold closing is performed. In this low-speed and low-pressure mold closing, as shown in FIG. 7, first, detection processing for abnormalities such as foreign matters is performed by the mold protection section Zd1.

  Furthermore, when this mold protection section Zd1 is completed, the monitoring process for the presence or absence of pinching, particularly focusing on the molded product, is performed by the mold closing monitor section that becomes the second mold protection section Zd2. As described above, when the thickness of the molded product is 0.1 [mm], the end position Xf is set between the mold closing position Xc and the front 0.1 [mm]. Therefore, it is possible to detect a thin sheet-shaped molded product remaining in the mold C without being discharged when the mold is opened. In fact, the molded product is a sheet-shaped molded product having a thickness of about 0.09 [mm]. However, it can be detected reliably.

  On the other hand, when the mold closing monitor section is completed, the mold closing position Xc for the mold C is detected by the closing position detection section Zc. This detection process is the same as step SP of the flowchart shown in FIG. 10 when the reference value Ds is set. If the increase rate ΔT obtained by the detection process for the mold closing position Xc in the closing position detection zone Zc reaches a preset set rate Ts, the process proceeds to high pressure mold clamping and high pressure mold clamping is performed. At the same time, the position of the crosshead 5 when the increase rate Ts reaches the set rate Ts is detected, and this position is taken as the detection value Dd of the mold closing position Xc. As described above, by setting the mold protection sections Zd1 and Zd2 and the closing position detection section Zc, the mold closing position Xc is detected after the mold protection sections Zd1 and Zd2 are completed. It is possible to stably and reliably perform both the protection process for the mold C and the detection process of the mold closing position Xc without causing interference.

  The detected detection value Dd is numerically displayed on the first display portion 62h and the second display portion 62x of the numerical value display portion 62 on the display screen 50, and is displayed on the graphic display portion 57g by the cursor 62c. Since the color (red) of the cursor 62c matches the color (red) of the color frame portion 62k displayed on the numerical value display portion 62 as described above, the operator uses the cursor 62c to determine the extent of the detected value Dd. As well as the detected value Dd of the mold closing position Xc.

  Further, the closed position detection mode is executed a plurality of times set in advance, and the detection value Dd is obtained from the average of the obtained plurality of mold closed positions Xc. As a result, a highly reliable detection value Dd from which noise components have been removed is obtained. When the detection value Dd is obtained, a deviation Ke from the preset reference value Ds, that is, Ke = Ds−Dd is obtained. If the deviation Ke is obtained, based on this deviation Ke, the correction for the end position Xe of the set mold protection section Zd1 and the end position Xf of the mold closing monitor section that becomes the second mold protection section Zd2 I do. Correction for the end positions Xe and Xf is performed as follows. Load torques Tf and Tr indicated by phantom lines in FIG. 7 indicate cases where the mold clamping force varies. The load torque Tr is a variation curve when the mold C is heated and thermally expanded, and is detected as the mold closing position Xcr before the normal mold closing position Xc. In this case, the mold clamping force increases. Therefore, if the mold opening position is the starting point (0) of the distance, the end position Xf (Xe) is corrected to be decreased by the deviation Ke. That is, in FIG. 7, Zc indicates the above-described closing position detection section between the end position Xf (Xe) and the mold closing position Xc, but when the mold closing position Xc is displaced, this closing position detection section Zc. The end position Xf (Xe) is corrected so that the distance is always constant.

  In particular, the load torque Tr shown in FIG. 7 is a fluctuation curve when the mold C is further heated, and the movable mold Cm starts to contact the fixed mold Cc before the end position Xf (Xe). Show. In this case, unless correction for the end position Xf (Xe) is performed, it is difficult to determine whether the variation of the load torque Tr is due to contact between the movable type Cm and the fixed type Cc based on normal operation or due to detection of foreign matter or the like. As a result, erroneous detection occurs. However, by correcting the end position Xf (Xe), it is possible to stably and reliably perform the foreign object detection process and the mold closing position Xc detection process according to the present embodiment without interfering with each other. .

  Similarly, the load torque Tf is a fluctuation curve when the tie bars 12... Are heated and thermally expanded, and is detected as the mold closing position Xcf at a position past the normal mold closing position Xc. In this case, the mold clamping force is reduced. Therefore, the end position Xf (Xe) is corrected to increase by the deviation Ke. In FIG. 7, Xd indicates a mold clamping end position. Note that even the mold closing positions Xc, Xcf, and Xcr related to such fluctuations in the mold clamping force can be accurately detected by the above-described closing position detection mode.

  On the other hand, since the allowable range Re for the deviation Ke is preset in the molding machine controller 40, the allowable range Re is compared with the obtained deviation Ke to determine whether the deviation Ke exceeds the allowable range Re. judge. Thereby, when the deviation Ke is within the allowable range Re, the mold clamping force is not corrected. Therefore, production operation is continued as it is. On the other hand, when the deviation Ke exceeds the allowable range Re, the detection value Dd is detected again. That is, in the example, the detection value Dd is continuously detected a plurality of times, and if the obtained deviation Ke continuously exceeds the allowable range Re, the mold clamping force is corrected. For example, when the detected value Dd is detected twice in succession and the obtained deviation Ke... Exceeds the allowable range Re twice, the mold clamping force is corrected. Therefore, when the allowable range Re is exceeded only once, it is determined that the cause is a temporary factor due to disturbance or the like, and correction is not performed. Thereby, stability and reliability when performing correction can be enhanced.

  The correction is performed according to the following processing procedure. The illustration shows an example in which correction is performed when the deviation Ke exceeds the allowable range Re twice in succession, and thus a plurality of deviations Ke are obtained. Therefore, in this example, a plurality of deviations Ke are averaged to obtain an average value. In the case of a plurality of deviations Ke, the average value may be used, or the latest deviation Ke may be used. Since the deviation Ke is a deviation with respect to the position of the crosshead 5, the deviation Ke is converted into a deviation with respect to the position of the movable platen 4 by a known conversion formula. Thereby, since the correction amount Ks for the movable platen 4 is obtained, the pressure receiving platen 2 is corrected to be displaced by this correction amount Ks. Thereby, the deviation Ke is canceled out.

  In the correction process, first, the geared motor 30 is driven and controlled based on the correction amount Ks, and the pressure receiving platen 2 is displaced in a direction in which the deviation Ke is eliminated. At this time, the pressure receiving platen 2 is moved at a lower speed (second speed Vs) than the normal speed. Further, the position detection of the pressure receiving platen 2 is detected by using an encoder pulse of a rotary encoder section 34 attached to the geared motor 30, and feedback control for the position is performed. When the pressure receiving platen 2 is moved to the target position corresponding to the correction amount Ks (deviation Ke), the geared motor 30 is controlled to be stopped and locked by the motor brake unit 33. Thus, in the present embodiment, the rotational speed of the motor shaft included in the motor section of the geared motor 30 is detected by the rotary encoder section 34, and the detection value obtained from the detection result of the rotary encoder section 34 and the position of the pressure receiving plate 2 are set. Since the geared motor 30 is feedback-controlled based on the command value (correction amount Ks), the high-voltage type is used even when the geared motor 30 incorporating the reduction gear mechanism is used as the mold thickness adjusting drive motor. The influence of error due to backlash that occurs during tightening can be eliminated, and control based on position detection can be performed accurately and stably.

  Although the correction process at the start of production has been described, as described above, the closed position detection mode is automatically executed when the preset closed position detection time or the number of closed position detection shots is reached even during production operation. Correction processing is performed. The correction process during production operation is performed at a specific timing set in advance without interrupting the molding cycle. As a specific timing without interrupting the molding cycle, a period other than the high-pressure mold clamping period, specifically, a mold opening period, a protruding period, an intermediate period, or the like can be used. Therefore, for example, if the protruding period is set as a period for performing the correction process, a correction command is output at the start timing of the protruding period, and the correction process is executed based on the correction command. In addition, manual correction by the operator is possible during production operation. In manual correction, an allowable range Re with respect to the deviation Ke is set in advance, and if the deviation Ke exceeds the allowable range Re, it is only necessary to be notified by an alarm or the like, and based on this, the operator performs correction manually. be able to. This makes it possible to make corrections that take into account the experience and know-how of the operator, and if necessary, depending on the type of molded product, it can be determined that correction is not necessary, and production can be prioritized. Therefore, the production operation (automatic molding) is continued as it is until the operator performs an operation for correction. Such manual correction and automatic correction may be used alone or in combination. Such a correction processing method can be selected in advance by the selection key 71 on the display screen 57 of the display.

  As described above, the best embodiment has been described in detail, but the present invention is not limited to such an embodiment, and the details, methods, configurations, numerical values, and the like are within the scope not departing from the gist of the present invention. It can be changed, added, or deleted arbitrarily.

  For example, in the first step F1, when the pressure receiving plate 2 reaches the mold closing position Xc, the toggle link mechanism 3 is bent to open the mold by a predetermined distance Lp, and thereafter, the pressure receiving plate 2 is moved to the predetermined distance. A step of extending the toggle link mechanism 3 after retracting by Ls has been provided, but tightening that occurs, such as using a large high-torque motor for the drive source (geared motor 30) for moving the pressure receiving plate 2, is provided. If it can be solved, this step can be omitted. Moreover, when using a servomotor for the drive source which moves the pressure receiving board 2, the 1st speed Vh and the 2nd speed Vs by servo control can be set. On the other hand, as the load torque T, an output (torque monitor) of the driver 52 is used, but a torque command that is an input of the torque limiter 51 may be used. Further, the load torque T accompanying the closing of the mold C is used as a physical quantity in the detection of the mold closing position Xc. However, as other physical quantities, the speed V of the crosshead 5 accompanying the closing of the mold C, the mold C The acceleration A of the crosshead 5 accompanying the closing, the estimated torque E generated by the disturbance accompanying the closing of the mold C, the positional deviation Ex of the crosshead 5 accompanying the closing of the mold C, and the like can also be used. These physical quantities including the load torque T can be used in combination. By combining them, the reliability can be further improved. Further, although the movement amount (displacement amount) of the crosshead 5 is used as the movement amount, the movement amount of the movable platen 4 can be directly used if necessary.

The flowchart which shows the process sequence of the reference value setting method which concerns on the best embodiment of this invention, A plan view of a toggle type mold clamping device capable of carrying out the same reference value setting method, Side configuration diagram showing the main part of a mold thickness adjusting device provided in the toggle type mold clamping device, Rear view showing the main part of the same thickness adjustment device, A block circuit diagram showing a part of a molding machine controller provided in the toggle type mold clamping device, A display screen view of a display provided in an injection molding machine for carrying out the reference value setting method; A variation curve diagram of load torque with respect to the position of the crosshead for explaining the reference value setting method, A display screen diagram showing another display mode of a display provided in an injection molding machine that implements the reference value setting method; Flow chart showing the processing procedure of automatic mold thickness adjustment mode in the standard value setting method A flowchart showing a processing procedure of a closed position detection mode in the reference value setting method,

Explanation of symbols

2 Pressure receiving plate 3 Toggle link mechanism 4 Movable platen 5 Crosshead Mc Toggle type clamping device C Mold Cm Movable type Cc Fixed type Xc Mold closing position S01 Automatic mold thickness adjustment process S03 Automatic closing position detection process S05 Mold temperature control Process F1 1st process F2 2nd process ΔX Constant movement amount ΔT Fluctuation rate of physical quantity T Load torque

Claims (3)

  In a mold closing position reference value setting method for setting a reference value of a mold closing position where a movable mold and a fixed mold touch when a mold is closed by a toggle mold clamping device, the position of the pressure receiving plate with respect to the mold is determined. When the automatic mold thickness adjustment process, which is set automatically, is executed and this automatic mold thickness adjustment process is completed, the mold can be moved by closing the mold before the mold temperature adjustment process for heating the mold and raising the temperature. The movement amount of the cross head in the panel or toggle type mold clamping device and the fluctuation amount of the load torque accompanying the closing of the mold are sequentially detected, and the fluctuation rate of the load torque with respect to the constant movement amount of the movable plate or the cross head ( In addition, the automatic closing position detecting step of automatically detecting the position when the fluctuation rate reaches a preset setting rate as the mold closing position is continuously executed and the automatic Closed position inspection Reference value setting method of a mold closed position and sets the detected mold closed position by step as a reference value.   In the automatic mold thickness adjusting step, the pressure receiving plate is advanced at a first speed that is a high speed from the retracted position with the toggle link mechanism extended, and when the pressure receiving plate reaches the mold closing position, the automatic mold thickness adjusting step is performed by a predetermined distance. After the first step of reversing, and after the first step, the pressure receiving plate is advanced at a second speed, which is a low speed, and when the mold closed position is reached, the toggle link mechanism is bent to open the mold by a predetermined distance. 2. A mold closing position reference value setting according to claim 1, further comprising a second step of advancing the pressure receiving plate by a distance corresponding to a clamping allowance for obtaining a target mold clamping force. Method.   In the first step, when the pressure receiving plate reaches the mold closing position, the toggle link mechanism is bent to open the mold by a predetermined distance, and thereafter, the pressure receiving plate is moved backward by a predetermined distance. 3. The method of adjusting a mold thickness of a toggle type mold clamping apparatus according to claim 2, wherein the toggle link mechanism is extended thereafter.

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