JP2007301873A - Method of clamping injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the trouble of impossibility of locking-up of the toggle link mechanism even when the variance of the thickness between two or more molds is large and ensures always stable clamping, independent of the variance of the thickness. <P>SOLUTION: When two or more molds C1 and C2, consisting of two or more switchable fixed or movable molds C1c and C2c, are clamped in order by meas of a single clamping device Mc, data for adjustment of the mold thickness of individual molds C1 and C2 are stored preliminarily. On clamping, an adjustment of the mold thickness of the mold C1 or C2 to be clamped is carried out on the basis of the data for adjustment of the mold thickness at such timing as not to interrupt the molding process, and the mold C1 or C2 is then clamped. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a mold clamping method for an injection molding machine that is suitable for use in performing sequential mold clamping on a plurality of types of molds configured by replacing a plurality of fixed molds or movable molds with a single mold clamping device. About.

  Conventionally, as a mold clamping method of an injection molding machine in which a plurality of types of molds configured by replacing a plurality of fixed molds are sequentially clamped by a single mold clamping device, Japanese Patent Laid-Open No. 2000-158500 is disclosed. There is known a mold clamping method of an injection molding machine disclosed in Japanese Patent Publication No. Gazette.

The mold clamping method of the injection molding machine disclosed in the publication is easy and quick adjustment for keeping the mold clamping force constant even when clamping using a plurality of molds having different mold thicknesses. In order to be able to do this, the setting part sets the mold thickness of each lower mold (fixed mold) attached to the upper surface of the rotary table and the clamping force to be applied to each mold. Based on the above, the CPU (calculation unit) derives the position of the crosshead where the set clamping force is generated for each of the lower molds, and the servo motor controlled by the control unit uses the toggle link mechanism. Clamping is performed by rotating the screw shaft that is screwed into the through-female screw hole of the crosshead to move the crosshead to the mold clamping completion position.
JP 2000-158500 A

  However, the above-described conventional clamping method of an injection molding machine has the following problems.

  First, because the method of adjusting the mold clamping force to a plurality of molds is fixed, it can be applied when the mold thickness deviation between the molds is very small, but the mold thickness deviation increases. In this case, there is a limit to the method for adjusting the mold clamping force to a plurality of molds to be constant, for example, the toggle link mechanism cannot be locked up and the mold clamping becomes unstable.

  Second, in order to adjust the mold clamping force according to the position of the crosshead, the actual mold clamping is subject to fluctuation factors of the mechanical error from the crosshead to the mold, for example, the expansion and contraction of the tie bar due to the influence of temperature change, etc. It cannot be reflected in power. In particular, recently, there is a tendency to use the minimum mold clamping force from the standpoints of extending the life of the mold, venting gas, and saving energy. , Which causes a decrease in the quality of the molded product and a decrease in yield.

  The object of the present invention is to provide a mold clamping method for an injection molding machine that solves the problems existing in the background art.

  In order to solve the above-described problem, the mold clamping method of the injection molding machine M according to the present invention is for a plurality of types of molds C1 and C2 configured by replacing a plurality of fixed molds (or movable molds) C1c and C2c. When performing mold clamping sequentially with one mold clamping device Mc, mold thickness adjustment data relating to mold thickness adjustment for each mold C1, C2 is stored in advance, and mold clamping is performed at the time of mold clamping. The mold thickness adjustment for the mold C1 (C2) based on the mold thickness adjustment data of C1 (C2) is performed at a specific timing without interrupting the molding process, and then the mold C1 (C2) is clamped. It is characterized by that.

  In this case, according to a preferred aspect of the invention, the specific timing is other than the replacement period of the fixed mold (or movable mold) C1c, the mold opening period of the mold clamping device Mc, or the mold clamping period in which no pressure is applied to the pressure receiving platen 2. Intermediate periods can be used. On the other hand, as the mold thickness adjustment data, pressure platen position data D1x and D2x related to the position of the pressure platen 2 with respect to the respective molds C1 and C2 can be used. Next, clamping is performed based on the deviation Ex of the pressure receiving plate position data D1x (D2x) related to C1 (C2) and the pressure receiving plate position data D2x (D1x) related to the mold C2 (C1) to be clamped next. The mold thickness can be adjusted for the mold C2 (C1). On the other hand, the mold thickness adjustment data includes reference pressure receiving plate position data Do related to the position of the pressure receiving plate 2 with respect to any one mold (specific mold) C1, movable mold Cm and fixed mold C1c in each mold C1, C2. The mold closing position data D1y and D2y related to the mold closing position Xc touched by C2c can be used, and when the mold is clamped, the mold based on the reference pressure receiving plate position data Do is used for the specific mold C1. While adjusting the thickness, the mold closing position data D1y related to the specific mold C1 and the mold closing position data D2y related to the mold C2 to be clamped next to the mold C2 other than the specific mold C1. Based on the deviation Ey, the mold thickness adjustment for the mold C2 to be clamped next can be performed. Further, when the mold is clamped, the mold closing position Xc touched by the movable mold Cm and the fixed mold C1c is detected, and the stored mold thickness adjustment data (pressure receiving position data D1x, reference pressure receiving position data) Do, mold closing position data D1y...) Can be corrected based on a deviation between the detected mold closing position Xc and a preset reference value Xs. As this reference value Xs, a mold thickness adjusting process for setting the position of the pressure receiving platen 2 with respect to the mold C1 (C2) is executed, and when this mold thickness adjusting process is completed, the mold closing position Xc is detected. The mold closing position Xc detected by the closed position detecting process can be used while the closed position detecting process is continuously executed. The mold closing position Xc sequentially detects the amount of movement of the crosshead 3 associated with the closing of the mold C1... And the amount of change in physical quantity (such as load torque) associated with the closing of the mold C1. By obtaining the fluctuation rate (including the fluctuation amount) of the physical quantity (load torque or the like) with respect to a certain movement amount, the position when this fluctuation rate reaches a preset setting rate can be used.

  According to the mold clamping method of the injection molding machine M according to the present invention by such a method, the following remarkable effects are obtained.

  (1) The mold thickness adjustment data related to the mold thickness adjustment for each mold C1... Is stored in advance, and the mold C1... Based on the mold thickness adjustment data of the mold C1. Since the mold thickness adjustment for the mold is performed at a specific timing that does not interrupt the molding process, the mold is clamped on the mold C1,... Even when the mold thickness deviation between C1 and C2 is large, it is possible to avoid the trouble that the toggle link mechanism cannot be locked up, and to always keep stable mold clamping regardless of the mold thickness deviation between the molds C1. It can be carried out.

  (2) According to a preferred embodiment, as a specific timing, an intermediate period other than a replacement period of the fixed mold (or movable mold) C1c..., A mold opening period of the mold clamping device Mc, or a mold clamping period in which no pressure is applied to the pressure receiving plate 2 If the period is used, the necessary mold thickness adjustment for each mold C1 can be performed stably and accurately without interrupting the molding process.

  (3) According to a preferred embodiment, the pressure platen position data D1x and D2x related to the position of the pressure platen 2 in each of the molds C1 and C2 are used as mold thickness adjustment data. Based on the deviation Ex of the pressure platen position data D1x (D2x) related to the mold C1 (C2) and the pressure platen position data D2x (D1x) related to the mold C2 (C1) to be clamped next If the mold thickness adjustment is performed on the mold C2 (C1) to be tightened, the pressure platen position data D1x can be reflected as it is on the mold thickness adjustment on the mold C1, so that it is easy and accurate (high accuracy). Mold thickness can be adjusted.

  (4) According to a preferred embodiment, as the mold thickness adjustment data, the reference pressure receiving plate position data Do related to the position of the pressure receiving plate 2 with respect to the specific mold C1, the movable mold Cm and the fixed molds C1c, C2c in the respective molds C1, C2. Using the mold closing position data D1y and D2y related to the mold closing position Xc touched by the mold, the mold thickness adjustment based on the reference pressure receiving plate position data Do is performed for the specific mold C1 at the time of clamping. Based on the deviation Ey between the mold closing position data D1y related to the specific mold C1 and the mold closing position data D2y related to the mold C2 to be clamped next with respect to the mold C2 other than the specific mold C1. Then, if the mold thickness adjustment is performed for the mold C2 to be clamped next, the mold thickness adjustment for obtaining the pressure receiving plate position data may be performed only once, and correction using the mold closing position Xc, etc. Easy processing Can.

  (5) According to a preferred embodiment, the mold closing position Xc touched by the movable mold Cm and the fixed mold C1c... Is detected during mold clamping, and the stored mold thickness adjustment data is used as the detected mold closing position. If correction is made based on the deviation between Xc and a preset reference value Xc, the expansion and contraction change of the tie bar due to the influence of temperature change or the like that is a variation factor of mechanical error from the crosshead 3 to the mold C1. Etc. can be reflected in the actual mold clamping force. In particular, even when the minimum mold clamping force is used from the viewpoints of extending the life of the mold, outgassing, energy saving, etc., the mold clamping in each mold C1. The accuracy can be improved, and it can contribute to the improvement of molding quality and the yield, and in addition, the mold C1 ... can be damaged or molded due to excessive clamping force or too little clamping force being set. Can avoid problems such as continuous occurrence

  (6) According to a preferred embodiment, a mold thickness adjusting step for setting the position of the pressure platen 2 with respect to the mold C1... Is executed as the reference value Xs. The reference position Xs can be accurately and stably set by continuously executing the closed position detecting process for detecting Xc and using the mold closed position Xc detected by the closed position detecting process.

  (7) According to a preferred embodiment, as the mold closing position Xc, the amount of movement of the crosshead 3 associated with the closing of the mold C1... And the amount of fluctuation of the physical quantity (load torque, etc.) associated with the closing of the mold C1. Then, by calculating the fluctuation rate (including the fluctuation amount) of the physical quantity (load torque, etc.) with respect to a certain amount of movement of the crosshead 3, if the position when this fluctuation rate reaches a preset setting rate is used, Accurate and stable detection of the mold closing position Xc can be performed.

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

  First, the configuration of an injection molding machine M that can perform the mold clamping method according to the present embodiment will be described with reference to FIGS.

  FIG. 3 shows the overall structure of the mold clamping device Mc in the injection molding machine M, in particular, the vertical injection molding machine M. Mb indicated by an imaginary line is an airframe, and the mold clamping device Mc is supported by the airframe Mb, and an injection device Mi partially indicated by an imaginary line is supported by the support mechanism 11 rising from the upper surface of the airframe Mb.

  The mold clamping device Mc includes a fixed support plate 12 disposed on the upper surface of the machine body Mb, and a rotary plate 13 having a circular plan view shown in FIG. 4 is disposed on the upper surface of the fixed support plate 12. Further, three tie bars 14 a, 14 b, 14 c that penetrate the fixed support board 12 in the vertical direction are provided, and each tie bar 14 a. In this case, as shown in FIG. 4, one tie bar 14 a is disposed to penetrate the center of the rotating disk 13, and the remaining two tie bars 14 b and 14 c are disposed outside the rotating disk 13. Therefore, the turntable 13 can be rotated around the tie bar 14a. The first fixed mold C1c and the second fixed mold C2c can be attached to positions 180 ° opposite to the upper surface of the turntable 13, respectively.

  A movable platen 15 is attached and fixed to the upper ends of the tie bars 14a projecting upward from the rotary platen 13. A movable Cm can be attached to the lower surface of the movable platen 15. Further, the pressure receiving plate 2 is supported at the lower ends of the tie bars 14a projecting downward from the fixed support plate 12, and in the space between the tie bars 14b, 14c and the tie bar 14a, the upper surface of the pressure receiving plate 2 and the fixed support plate 12 are provided. A toggle link mechanism L is installed between the lower surfaces. As shown in FIG. 5, the toggle link mechanism L includes a pair of first links La and La that are pivotally supported by the pressure receiving plate 2, a pair of output links Lc and Lc that are pivotally supported by the fixed support plate 12, and a first link. A pair of second links Lb and Lb coupled to a support shaft between La and La and the output links Lc and Lc are provided, and the second links Lb and Lb are supported on the crosshead 3.

  A mold clamping drive unit 16 is disposed between the pressure receiving plate 2 and the crosshead 3. The mold clamping drive unit 16 includes a ball screw mechanism unit 17 and a rotation drive mechanism unit 18 disposed on the pressure receiving plate 2. The ball screw mechanism portion 17 includes a nut portion 17n integrally attached to the cross head 3 and a ball screw portion 17s screwed to the nut portion 17n, and one end of the ball screw portion 17s passes through the pressure receiving plate 2 and It protrudes from the lower surface of the pressure platen 2. The rotary drive mechanism 18 includes a mold clamping servo motor 19, a drive gear 21 attached to the motor shaft of the servo motor 19, a driven gear 22 attached to the ball screw portion 17s, and a gap between the drive gear 21 and the driven gear 22. A timing belt 23 is provided. The mold clamping servo motor 19 is provided with a rotary encoder 19e for detecting the rotation speed of the mold clamping servo motor 19.

  Thus, when the mold clamping servo motor 19 is operated, the drive gear 21 rotates, 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 17s rotates. The nut portion 17n moves back and forth (up and down). As a result, the cross head 3 integrated with the nut portion 17n moves up and down, and the toggle link mechanism L bends or extends, so that the movable platen 15 via the pressure receiving plate 2 and the three tie bars 14a. Move upward (upward) or mold closing (downward).

  Further, a mold thickness adjusting mechanism 25 is disposed on the pressure receiving platen 2. The mold thickness adjusting mechanism portion 25 includes an adjusting mechanism in which screw portions 26 are formed on the rear end side of the three tie bars 14a, and adjustment nuts 27 are screwed into the screw portions 26, respectively. In this case, the adjusting nuts 27 also serve as stoppers for the pressure receiving plate 2. A mold thickness adjusting motor 29 using a geared motor is disposed on the upper surface of the pressure receiving plate 2. The output shaft 29s of the mold thickness adjusting motor 29 protrudes from the lower surface of the pressure receiving plate 2, and the drive gear 30 shown in FIG. 6 is attached to the tip of the output shaft 29s, and small gears 31 are respectively attached to the adjusting nuts 27. Install as a unit. The adjustment nuts 27 and the small gears 31 are coaxial. Further, a large gear 32 that meshes with each of the small gears 31 and the drive gear 30 is provided. The large gear 32 is formed in a ring shape, and a rail portion provided along the inner peripheral surface is supported by four support rollers 33 attached to the pressure receiving plate 2.

  Accordingly, when the mold thickness adjusting motor 29 is operated, the large gear 32 is rotated by the rotation of the drive gear 30 and the small gears 31 are simultaneously rotated by the rotation of the large gear 32. Then, the adjustment nuts 27 that rotate integrally with the small gears 31 move forward and backward (up and down) along the screw portions 26 of the tie bars 14 a, so that the pressure receiving plate 2 also moves up and down, and the position of the pressure receiving plate 2 Adjustment, that is, mold thickness adjustment is performed.

  On the other hand, a rotating disk drive mechanism 40 is disposed on the lower surface of the fixed support board 12. As shown in FIGS. 3 and 4, the turntable drive mechanism 40 includes a turntable drive motor 41 attached to the lower surface of the fixed support plate 12. The motor shaft of the rotary disk drive motor 41 passes through the fixed support board 12 and protrudes from the upper surface of the fixed support board 12, and a drive pinion 42 is attached to the tip of the motor shaft. A driven gear 43 that is coaxial with the rotating disk 13 is fixed to the lower surface of the rotating disk 13, and the driven gear 43 is engaged with the drive pinion 42.

  Accordingly, when the rotating disk drive motor 41 is operated, the driven gear 43 is rotated by the rotation of the driving pinion 42, and the rotating disk 13 integrated with the driven gear 43 is rotated. In this case, the turntable 13 rotates in units of 180 [°], and the stop position at this time is determined by detecting a limit switch or the like. Therefore, the first fixed mold C1c and the second fixed mold C2c are alternately arranged directly below the movable mold Cm.

  An ejector mechanism 45 includes an ejector motor 46. By operating the ejector motor 46, the ejector pin 47 can be moved back and forth (up and down displacement). On the other hand, a molding machine controller 50 connects the above-described mold clamping servo motor 19, mold thickness adjusting motor 29, rotating disk drive motor 41, and ejector motor 46. The molding machine controller 50 includes a control system 51 having at least a computer function and a sequence control function for controlling the operation of each of the motors 19, 29, 41, and 46, and an internal memory 52 that can store and read various data. It has. In FIG. 5, reference numeral 48 denotes a mechanical safety device.

  Next, a mold clamping method according to the present embodiment using such a vertical injection molding machine M will be described according to the flowcharts shown in FIGS. 1 and 2 with reference to FIGS.

  First, prior to production operation, mold thickness adjustment data relating to mold thickness adjustment for the first mold C1 and the second mold C2 to be used, that is, pressure platen position data D1x and D2x are detected and stored (registered). . Hereinafter, this processing method will be described with reference to the flowchart shown in FIG.

  First, as shown in FIGS. 3 and 4, the first fixed mold C1c and the second fixed mold C2c are attached to the upper surface of the rotating disk 13, and the movable mold Cm is attached to the lower surface of the movable board 15 (step S1). Thereby, the first mold C1 is configured by combining the first fixed mold C1c and the movable mold Cm, and the second mold C2 is configured by combining the second fixed mold C2c and the movable mold Cm. The

  When the attachment of the first fixed mold C1c, the second fixed mold C2c, and the movable mold Cm is completed, the mold thickness of the first mold C1 is adjusted (step S2). In this case, the control system 51 executes a series of automatic mold thickness adjustment processes in which the position (relative position) of the pressure receiving plate 2 is automatically set (adjusted) in the automatic mold thickness adjustment mode.

  This automatic mold thickness adjustment step (automatic mold thickness adjustment mode) will be specifically described. First, the mold thickness adjusting motor 29 is controlled to move the tie bars 14a (movable platen 15) to a predetermined ascending position, and then the mold clamping servo motor 19 is controlled to extend the toggle link mechanism L ( (Extended state). Then, the mold thickness adjusting motor 29 is controlled to lower the tie bars 14a... (Movable platen 15) and stop when the first mold C1 reaches the mold closing position. This mold closing position is a position where the movable mold Cm and the first fixed mold C1c are touched, and is automatically detected by executing a series of automatic closing position detection steps in the automatic closing position detection mode.

  In this automatic closing position detection step, the movable platen 15 is moved down by the control of the mold thickness adjusting motor 29. Therefore, the relative movement amount of the pressure receiving platen 2 with respect to the tie bars 14a ... associated with the closing of the first die C1 and the first die C1. The amount of fluctuation of the load torque with respect to a certain amount of movement of the pressure receiving platen 2 is sequentially detected, for example, the amount of fluctuation of the load torque with respect to the constant movement amount of the pressure receiving platen 2, and the fluctuation rate reaches a preset set rate. The position may be detected as the mold closing position, and the mold thickness adjusting motor 29 is stopped at this point. Thereby, an automatic closing position detection process is complete | finished. Note that the variation rate may be a variation amount.

  Next, the mold clamping servomotor 19 is controlled to bend the toggle link mechanism L, whereby the movable platen 15 is raised by a predetermined distance Sp to perform a slight mold opening. As a result, it is possible to avoid the problem of being unable to move backward due to tightening, and to move to the next operation with certainty. Then, the mold thickness adjusting motor 29 is controlled to raise the movable platen 15 by a predetermined distance Ss, and thereafter, the mold clamping servomotor 19 is controlled to extend the toggle link mechanism L, thereby moving the movable platen 15 to the above-described state. Is lowered by the same distance as the predetermined distance Sp. Further, the movable platen 15 is lowered by controlling the mold thickness adjusting motor 29, and when the mold closing position is reached, the mold thickness adjusting motor 29 is stopped. Next, the mold clamping servomotor 19 is controlled to bend the toggle link mechanism L, whereby the movable platen 15 is raised by a predetermined distance Sr to perform a slight mold opening. In this case, the distance Sr is a movement for setting a tightening allowance, and a distance that can secure at least the tightening allowance is selected. Then, the mold thickness adjusting motor 29 is controlled, and the movable platen 15 is lowered by a distance Sc corresponding to a clamping allowance for obtaining a target mold clamping force. Since the relationship between the distance when the movable platen 15 is lowered from the mold closing position and the mold clamping force is set in advance, the distance Sc corresponding to the clamping allowance for obtaining the target mold clamping force is selected. Can do. Thereby, the automatic mold thickness adjustment mode ends (step S3). The illustrated automatic mold thickness adjustment mode is an example, and various other mold thickness adjustment methods can be used.

  On the other hand, when the automatic mold thickness adjustment process for the first mold C1 is completed, the mold is opened, and the control system 51 detects and loads the pressure receiving platen position that is the adjustment position of the first mold C1 (step). S4), and stored (registered) in the internal memory 52 as the pressure platen position data D1x (step S5). This pressure receiving plate position may be obtained from the number of rotations of the mold thickness adjusting motor 29 or may be detected by a separate linear scale detector or the like. The relative position of the pressure receiving plate 2 with respect to the tie bars 14a. Capture.

  When the registration of the pressure receiving plate position data D1x for the first mold C1 is completed, the rotary plate drive motor 41 is controlled to rotate the rotary plate 13 by 180 [deg.] (Step S6). As a result, the first fixed mold C1c and the second fixed mold C2c are interchanged, and the second fixed mold C2c is positioned directly below the movable mold Cm.

  Next, the mold thickness of the second mold C2 is adjusted (step S7). In this case, in the control system 51, as in the case of the first mold C1 described above, a series of automatic mold thicknesses are performed in an automatic mold thickness adjustment mode in which the position (relative position) of the pressure receiving plate 2 is automatically set (adjusted). An adjustment process is executed, and the pressure receiving platen position that is the adjustment position of the second mold C2 is detected and taken in (steps S8 and S9), and further stored (registered) in the internal memory 52 as pressure receiving plate position data D2x. (Step S10). Thereby, the registration process of the pressure receiving platen position data D1x and D2x ends.

  Next, the mold clamping operation during production operation will be described with reference to the flowchart shown in FIG.

  Now, the vertical injection molding machine M performs molding by the first mold C1. In this case, the toggle link mechanism L is in a bent state, and the movable platen 15 is in the raised position (die opening position). First, a mold clamping process is performed on the first mold C1 (step S11). In the mold clamping process, the mold clamping servomotor 19 is controlled by the control system 51 to extend the toggle link mechanism L. As a result, the pressure receiving plate 2 and the movable platen 15 are lowered, and the first mold C1 is clamped. An injection process is performed upon completion of the mold clamping process (step S12). In the injection process, the injection device Mi performs nozzle touch with respect to the first mold C1, and injection filling of the molten resin is performed from the injection device Mi to the first mold C1. A mold opening process is performed upon completion of the injection process (step S13). In the mold opening process, the mold clamping servomotor 19 is controlled, and the toggle link mechanism L is shortened to raise the movable platen 15.

  Next, the rotating disk drive motor 41 is controlled to rotate the rotating disk 13 (step S14). Then, during the rotation of the turntable 13, the mold thickness adjustment is performed on the second mold C2 using the fixed mold on the anti-clamping side, ie, the second fixed mold C2c. In this case, first, the pressure platen position data D2x related to the second mold C2 is read from the internal memory 52 (step S15). Further, a deviation Ex between the read pressure platen position data D2x and the pressure platen position data D1x when the mold thickness is adjusted immediately before the current position of the pressure platen 2 is calculated (step S16). Then, mold thickness adjustment is performed based on the calculated deviation Ex. Specifically, the mold thickness adjusting motor 29 is controlled to relatively move the pressure receiving platen 2 by a movement amount corresponding to the deviation Ex. If the target position (adjustment position) corresponding to the deviation Ex is reached by moving the pressure receiving platen 2, the mold thickness adjustment motor 29 is stopped (steps S17, S18, S19).

  The mold thickness adjustment in this case is performed while the turntable 13 is rotating, that is, during the replacement period of the first fixed mold C1c and the second fixed mold C2c, and this replacement period has a specific timing that does not interrupt the molding process. It becomes. Therefore, by using such a replacement period, there is an advantage that necessary mold thickness adjustment for each mold C1... Can be performed stably and accurately without interrupting the molding process. Further, by using the pressure platen position data D1x... As the mold thickness adjustment data, the pressure platen position data D1x... Can be directly reflected in the mold thickness adjustment for the mold C1. Adjustments can be made.

  On the other hand, when the rotation amount (rotation angle) of the turntable 13 reaches 180 [°] and the rotation of the turntable 13 is stopped (finished), the ejector motor 46 is controlled to project the molded product in the first fixed mold C1c. (Steps S20 and S21). Then, when the next process is continued, after the end of the protrusion, the turntable 13 rotates 180 [°] and the mold clamping process is performed again (steps S22, S11...). As described above, the mold thickness adjustment for the first mold C1 using the first fixed mold C1c is performed while the turntable 13 is rotating. On the second fixed mold C2c side, the same process as that on the first fixed mold C1c side proceeds except that it is delayed by 1/2 cycle.

  By the way, when performing mold clamping, the mold closing position Xc touched by the movable mold Cm and the fixed mold C1c (C2c) is detected, and the stored pressure platen position data D1x and D2x are detected. Correction can be made based on a deviation between the position Xc and a preset reference value Xc. In this case, the mold closing position Xc sequentially detects the amount of movement of the crosshead 3 associated with the closing of the mold C1... And the physical amount associated with the closing of the mold C1. By obtaining the fluctuation rate (including the fluctuation amount) of the load torque with respect to the constant movement amount, the position when the fluctuation rate reaches a preset setting rate can be detected as the mold closing position Xc. By such a detection method, the mold closing position Xc can be accurately and stably detected. Further, the reference value Xs is obtained by executing the automatic mold thickness adjusting process described above for automatically setting the position of the pressure receiving plate 2 with respect to the mold C1,. While continuing the automatic closing position detection process which detects Xc automatically, the metal mold closing position Xc detected by this automatic closing position detection process can be used. By using such a reference value Xs, the reference value Xs can be set accurately and stably, and a problem that the setting of the reference value Xs is omitted due to an error such as forgetting by the operator can be avoided. Xs can be set reliably. In addition, although the automatic mold thickness adjustment process and the automatic closing position detection process were illustrated, it is not necessarily required to be automatic.

  By performing such correction on the pressure platen position data D1x, D2x, the tie bar expansion / contraction change due to the influence of temperature change, etc., which is a variation factor of the mechanical error from the crosshead 3 to the mold C1,. It can be reflected in the clamping force, and in particular, even when the minimum clamping force is used from the viewpoint of extending the life of the die, outgassing, energy saving, etc., increase the clamping accuracy in each die C1. In addition to contributing to improvement of molding quality and yield, in addition, excessive mold clamping force or excessive mold clamping force is set, resulting in damage to the mold C1. There is an advantage that the problem can be avoided.

  Therefore, according to such a mold clamping method according to this embodiment, mold thickness adjustment data D1 related to mold thickness adjustment for each mold C1 is stored in advance, and mold clamping is performed at the time of mold clamping. The mold thickness adjustment for the mold C1... Based on the mold thickness adjustment data of the mold C1... Is performed at a specific timing without interrupting the molding process, and then the mold C1 is clamped. Unlike the method of adjusting the tightening force to be constant, even when the mold thickness deviation between the plurality of molds C1... Is large, it is possible to avoid the problem that the toggle link mechanism cannot be locked up, and between the molds C1. Stable mold clamping can always be performed regardless of the mold thickness deviation.

  In particular, the mold clamping method according to the present embodiment is optimal when a necessary minimum mold clamping force is applied in actual molding. That is, even when it is not a problem when a marginal mold clamping force is applied to the necessary mold clamping force, when the necessary minimum mold clamping force is applied, between the molds C1. Even a slight mold thickness error has a non-negligible effect on the clamping force. For example, when the mold thickness error between the first mold C1 and the second mold C2 is 0.01 [mm], the influence on the mold clamping force is calculated to 1 to 3 [t] in a normal model. Become. Therefore, when a mold clamping force having a margin far exceeding 1 to 3 [t] is added as a mold clamping force, an error of about 1 to 3 [t] is not a problem, but is necessary. When the minimum mold clamping force is applied and the margin is about 1 [t], the error of 1 to 3 [t] greatly affects the mold clamping force to be set. In addition, there are not a few cases in which a heat insulating plate is usually interposed in the mold C1. In practice, the influence of the heat insulating plate is added. In the case of a heat insulating plate, since there is usually an error of 0.05 [mm], the fluctuation of the mold clamping force with the heat insulating plate added reaches 6 to 18 [t]. In the mold clamping method according to the present embodiment, the mold thickness adjustment based on the mold thickness adjustment data is performed on each mold C1... Every time mold clamping is performed, so that an accurate mold clamping force can always be obtained. .

  Next, an injection molding machine M and a mold clamping method according to a modified embodiment of the present invention will be described with reference to FIGS.

  FIG. 7 shows a modified embodiment of the injection molding machine M. In the injection molding machine M, the mold clamping device Mc is configured as a vertical mold, and the injection device Mi is configured as a horizontal mold. In this case, the point that the rotating disk 13 is disposed on the upper surface of the machine body Mb has the same form as the vertical injection molding machine M shown in FIG. 1, but the lower end of the tie bar 60 is fixed to the upper surface of the machine body Mb. The pressure receiving plate 2 is provided at the upper end of the tie bar 60, the movable platen 15 is slidably supported by the tie bars 60, and the mold clamping drive mechanism 61 is installed between the movable platen 15 and the pressure receiving plate 2 so as to be movable. The board 15 is moved up and down, and this point is greatly different from the vertical injection molding machine M shown in FIG. Even the injection molding machine M having such a configuration includes the first mold C1 and the second mold C2 described above, and the mold thickness can be adjusted with respect to each of the first mold C1 and the second mold C2. Can be implemented (applied) as in the case of FIG.

  FIG. 8 shows a modified embodiment of the mold clamping method. The mold clamping method (processing method for registering mold thickness adjustment data) shown in the flowchart of FIG. 8 is a pressure receiving plate for any one mold (specific mold), for example, the first mold C1 as the mold thickness adjustment data. 2 and the mold closing position data D1y and D2y related to the mold closing position Xc touched by the movable mold Cm and the fixed molds C1c and C2c in the molds C1 and C2 are used. . Therefore, when the movable mold Cm and the fixed molds C1c and C2c (molds C1 and C2) are attached to the mold clamping device Mc, the mold thickness is adjusted only for the first mold (specific mold) C1. Thus, as in the case of the embodiment shown in FIG. 1, the pressure platen position data is obtained, and this pressure platen position data is stored (registered) as the reference pressure platen position data Do (steps S51, S52, S53). , S54). When the mold thickness adjustment for the first mold C1 is completed, the mold clamping servo motor 19 is operated to detect the mold closing position Xc, and the detected mold closing position Xc is used as the mold of the first mold C1. The closed position data D1y is stored (registered) in the internal memory 52 (steps S55 and S56).

  Thereafter, the rotating disk drive motor 41 is controlled to rotate the rotating disk 13 by 180 [°] (step S57). As a result, the first fixed mold C1c and the second fixed mold C2c are interchanged, and the second fixed mold C2c is positioned directly below the movable mold Cm. On the other hand, mold thickness adjustment is not performed for the second mold C2. In this case, in the control system 51, the mold clamping servo motor 19 is operated to detect the mold closing position Xc, and the detected mold closing position Xc is used as the mold closing position data D2y of the second mold C2 in the internal memory 52. (Registered) (steps S58 and S59).

  On the other hand, at the time of mold clamping, mold thickness adjustment is performed on the first mold C1 based on the reference pressure receiving platen position data Do. However, the second mold is a mold other than the first mold C1. For C2, the mold clamping position data D1y for the first mold C1 and the deviation Ey of the mold closing position data D2y for the second mold C2 to be clamped next are then clamped. The mold thickness is adjusted for the second mold C2 that performs the above.

  According to the mold clamping method according to this modified embodiment, the mold thickness adjustment for obtaining the pressure receiving plate position data can be performed only once, and processing such as correction using the mold closing position Xc can be easily performed. There are advantages. As described above, when performing mold clamping, the mold closing position Xc touched by the movable mold Cm and the fixed mold C1c (C2c) is detected and stored in the same manner as the pressure receiving plate position data D1x and D2x. The reference pressure receiving platen position data Do and the mold closing position data D1y, D2y can be corrected based on the deviation between the detected mold closing position Xc and a preset reference value Xc.

  Although the best embodiment has been described in detail above, the present invention is not limited to such an embodiment, and departs from the gist of the present invention in the detailed configuration, shape, material, quantity, numerical value, and the like. It can be changed, added, or deleted as long as it is not.

  For example, the case where the plurality of types of molds C1 and C2 are configured by replacing a plurality of fixed molds C1c and C2c has been described, but the case may be configured by replacing a plurality of movable molds. In addition, although two types of molds C1 and C2 are illustrated as the plurality of types of molds C1 and C2, three or more types may be used. On the other hand, the pressure platen position data D1x..., The reference pressure platen position data Do, the mold closing position data D1y... Are exemplified as the mold thickness adjustment data, but other data that can be used as the mold thickness adjustment data is not excluded. Furthermore, as the specific timing, the replacement period of the fixed mold (or movable mold) C1c... Is exemplified, but the mold opening period of the mold clamping device Mc, the intermediate period other than the mold clamping period in which no pressure is applied to the pressure receiving plate 2, and the like. It may be used. As another form of injection molding machine M, a plurality of fixed molds or movable molds are arranged on the upper side, and a single movable mold or fixed mold is arranged on the lower side, or without using the turntable 13. The present invention can be similarly applied to various other forms of injection molding machines M, such as a form in which a fixed mold or a movable mold is replaced by a slide board. Moreover, although the case where the electric injection molding machine M was used was illustrated, the present invention can be similarly applied to an injection molding machine of another drive type such as a hydraulic injection molding machine.

The flowchart which shows the process sequence at the time of registering mold thickness adjustment data with the mold-clamping method which concerns on the best embodiment of this invention, A flowchart showing a processing procedure when performing mold clamping in the mold clamping method; Side view of an injection molding machine that can carry out the same mold clamping method, Plan view of the injection molding machine, Rear view of the injection molding machine Bottom view of mold thickness adjusting mechanism in the same injection molding machine, The external appearance block diagram of the injection molding machine which concerns on the modified embodiment of this invention, The flowchart which shows the process sequence at the time of registering mold thickness adjustment data by the mold clamping method which concerns on the modified embodiment of this invention,

Explanation of symbols

  2: pressure receiving plate, M: injection molding machine, Mc: mold clamping device, C1: mold (first mold), C2: mold (second mold), C1c: fixed mold (first fixed mold), C2c: Fixed type (second fixed type), Cm: Movable type, D1x: Pressure receiving plate position data, D2x: Pressure receiving plate position data, Do: Reference pressure receiving plate position data, D1y: Mold closing position data, D2y: Mold Closed position data

Claims (9)

  In a mold clamping method of an injection molding machine in which a plurality of types of molds configured by replacing a plurality of fixed molds or movable molds are sequentially clamped by a single mold clamping device, the mold thickness for each mold is previously determined. Stores mold thickness adjustment data related to adjustment, and performs mold thickness adjustment for the mold based on the mold thickness adjustment data of the mold to be clamped at a specific timing that does not interrupt the molding process. Then, a mold clamping method for an injection molding machine, wherein mold clamping is performed on the mold.   The specific timing uses an intermediate period other than a replacement period of the fixed mold (the movable mold), a mold opening period of the mold clamping device, or a mold clamping period in which no pressure is applied to the pressure receiving platen. Item 2. A mold clamping method for an injection molding machine according to Item 1.   2. The mold clamping method for an injection molding machine according to claim 1, wherein the mold thickness adjustment data uses pressure platen position data related to the position of the pressure plate for each mold.   At the time of mold clamping, based on the deviation between the pressure platen position data related to the mold currently clamped and the pressure platen position data related to the mold to be clamped next, the mold to be clamped next 4. The mold clamping method for an injection molding machine according to claim 3, wherein the mold thickness is adjusted.   The mold thickness adjustment data relates to the reference pressure receiving plate position data related to the position of the pressure receiving plate with respect to any one mold (specific mold), and the mold closing position touched by the movable mold and the fixed mold in each mold. 2. The mold clamping method for an injection molding machine according to claim 1, wherein mold closing position data is used.   During mold clamping, mold thickness adjustment is performed on the specific mold based on the reference pressure receiving plate position data, and molds related to the specific mold are closed on molds other than the specific mold. 6. The injection molding according to claim 5, wherein the mold thickness is adjusted for the mold to be clamped next based on the deviation between the position data and the mold closing position data relating to the mold to be clamped next. The mold clamping method.   During mold clamping, the mold closing position touched by the movable mold and the fixed mold is detected, and the stored mold thickness adjustment data is based on the deviation between the detected mold closing position and a preset reference value. The mold clamping method for an injection molding machine according to claim 1, wherein correction is performed.   The reference value is determined by executing a mold thickness adjusting process for setting the position of the pressure receiving plate with respect to the mold, and when the mold thickness adjusting process is completed, continue the closed position detecting process for detecting the mold closed position. 8. The mold clamping method for an injection molding machine according to claim 7, wherein the mold closing position detected by the closing position detecting step is used.   The mold closing position sequentially detects the amount of movement of the crosshead accompanying the closing of the mold and the amount of fluctuation of the physical quantity accompanying closing of the mold, and the rate of change of the physical quantity relative to the constant amount of movement of the crosshead (the amount of fluctuation). 9. The mold clamping method for an injection molding machine according to claim 5, wherein a position at which the variation rate reaches a preset set rate is obtained by calculating

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