JP4089906B2 - Molding monitoring method in pressure filling molding of resin - Google Patents

Description

  The present invention relates to a molding monitoring method in pressure filling molding in which a resin stored in a semi-molten state is pressurized with a clamping force and filled into a cavity.

  As a conventional means for molding a thermosetting resin, pressure filling molding called runnerless molding is known because a large number of molded products can be simultaneously molded without providing a runner. In this molding method, the material resin is semi-melted by a screw-equipped supply device, and after filling the resin chamber semi-melted by the screw into the storage chamber with a variable volume attached to the stationary platen, the storage chamber is stored. By pressing the mold attached to the pressure side and the movable plate, the semi-molten resin in the storage chamber is pressurized by the movable part, and the cavity is filled into the cavity from the nozzle in the mold provided in the storage chamber, Molding into a desired product.

In such pressure filling molding, the semi-molten resin in the storage chamber is pressurized by a powerful mold clamping force and filled into the cavity from the nozzle in the mold, so than the resin filled into the cavity in the molten state, Even a semi-molten resin with extremely high viscosity can be reliably molded without a shortage of filling amount, and the temperature of the semi-molten resin can be controlled to a temperature that does not cure in the storage chamber. However, since the resin is not cured and the semi-molten resin can be continuously supplied in the molding process, continuous molding is possible, yield is improved, and molding efficiency is improved.
JP 2002-96355 A

  The storage chamber in this pressure filling molding is controlled to a temperature at which the semi-molten resin does not cure, but the resin viscosity in the storage chamber fluctuates greatly due to unexpected pauses during molding or poor temperature control of the storage chamber. If the resin viscosity rises, it becomes a change in resistance to mold clamping force and resin flow resistance, the amount of resin filling from the nozzle in the mold to the cavity becomes unstable, and the molding condition is uneven. It tends to occur.

  Also, as the resin viscosity in the storage chamber changes, the filling pressure into the cavity also changes, and if the resin viscosity increases, short shots, blurring, burrs, etc. occur, resulting in defective molding. However, some of them may have insufficient density due to the intended use of the molded product. Molded products with extremely low density are also deteriorated in quality, so they are handled as defective molded products that do not circulate in the market, and if this is mixed with non-defective products, sorting work is required, which increases the number of molding processes. Has a problem.

  The present invention was conceived in order to solve the above-mentioned conventional problems, and its purpose is to grasp mold defects caused by viscosity change of the stored semi-molten resin or clogging of nozzles in the mold. It is an object of the present invention to provide a new molding monitoring method in pressure filling molding that can be easily performed by monitoring the time and position from the mold closing time to the mold clamping end time.

  In the present invention according to the above-described object, the material resin is made into a semi-molten state by a supply device inside the screw, and after filling the semi-molten resin into a storage chamber having a variable volume attached to the fixed plate from the supply device, When the mold attached to the storage chamber side and the movable plate is clamped to pressurize the semi-molten resin in the storage chamber and fill the cavity with the semi-molten resin from the nozzle in the mold provided in the storage chamber. A monitor width is set for the moving time from the mold closing time until the mold speed falls below the predetermined speed. If the moving time exceeds the monitor width, molding failure is assumed. The moving time is the mold closing time. Alternatively, the timing is started when the driving pressure of the moving means of the movable plate reaches the set pressure by closing the mold.

  In addition, the present invention sets a monitor width with respect to the mold position (mold parting position) at the end of mold clamping, and if the mold position exceeds the monitor width, molding failure occurs. When the mold position at the time exceeds a preset correction value, the resin amount for the next molded product is corrected by a preset correction amount.

  In this invention, when the resin viscosity of the storage chamber changes, the resin amount and resin density of the semi-molten resin filled in the cavity also change. Therefore, the mold moving time from the mold closing time and the mold closing time The mold position will also change. If the time and position are within the monitor width, it can be grasped as a non-defective product, and if it is out of the monitor width, it can be grasped as a defective product. can do.

  In addition, when the mold position at the end of mold clamping reaches a correction value set with a width narrower than the monitor width, the amount of resin supplied from the supply device to the storage chamber is changed to a correction amount corresponding to the correction value. In order to compensate for this, the most suitable amount of resin at that time is stored in the storage chamber, and even when many shots of resin are stored and molded one shot at a time, the amount of resin is insufficient. Therefore, the quality of the molded product by pressure filling molding is further improved.

FIG. 1 shows an example of a pressure filling molding machine in which the present invention is adopted.
In the figure, reference numeral 1 denotes a mold clamping device that uses hydraulic pressure as a driving force. A movable plate 6 is inserted into and supported by a tie bar between a fixed plate 3 provided on the machine base 2 and a rear plate 5 integrated with the mold clamping cylinder 4. And ready to move. This movable platen 6 is connected to a mold clamping ram 7 protruding from the mold clamping cylinder 4, and moves forward and backward with respect to the fixed platen 3 by the mold clamping ram 7, and is divided and attached to the fixed platen side and the movable platen side. The supply device 10 using an inline screw type injection device is provided on the machine base on the fixed plate side of the mold clamping device 1, which has a normal structure for opening and closing the molds 8 and 9, and the mold clamping. The supply nozzle 10 b is provided toward the mold clamping device 1.

  Reference numeral 11 denotes a mold base mounted on the inner side of the fixed platen 3, and, as shown in FIG. 2, slides with a fixed portion 12 having a convex cross section on the fixed platen side and a clearance at which the resin does not leak into the fixed portion 12. A semi-molten resin reservoir 14 whose volume (for example, a maximum of 800 ml) is variable depending on the position of the movable portion 13 includes a fixed portion 12 and a movable portion 13. It is supposed to occur during

  A bush having a supply passage 15 is fitted in the central portion of the fixing portion 12, and the supply nozzle 10b is touched to the opening end of the bushing so that the semi-molten resin in the heating cylinder 10a is moved forward. Thus, the storage chamber 14 is filled from the supply device 10 and can be stored. The semi-molten resin is stored while the movable portion 13 is pressed and moved by the filling pressure generated by the advance of the screw 10c to expand the storage chamber 14, and the pressing movement is performed between the pin and the guide provided between the fixed portion 12 and the movable portion 13. The restriction plate 16 on both sides of the groove is limited to an allowable range.

  The plate-like portion 13a of the movable portion 13 facing the movable plate 6 also serves as a semi-molten resin compression plate and a mold mounting plate of the storage chamber 14, and the plate-like portion 13a has a large number of cavities. In-mold nozzles 17 for filling are formed protruding at equal intervals. In addition, a heat insulating material 18 is provided on the plate surface except for the nozzle portion, and a heat insulating space 19 is provided between the heat insulating material 18 and the same number of gate portions 8a for nozzle touch with the in-mold nozzles 17 are provided. The plate-shaped mold is attached as the mold 8 on the fixed platen side. The mold 8 is connected to the movable part 13 by restricting plates 20 provided on both sides over the movable part 13, and moves within the allowable range of the restricting plate 20 when the mold is opened and closed, via the plate-like part 13 a and the heat insulating material 18. Touch and leave.

  On the inner surface of the movable plate 6 facing the mold 8, a block-shaped mold in which the same number of cavities 21 (for example, volumes 1 to 10 ml) as the gate portions 8a of the mold 8 are recessed at the same position is movable. It is attached as a mold 9 on the panel side. The mold 9 is moved forward together with the movable plate 6 by the mold clamping ram 7 to close the mold 8 and is further clamped to the mold 8. Further, when the movable platen 6 is moved backward by the mold clamping ram 7, the mold is opened away from the mold 8.

  Although the mold base 11 and the mold 8 are omitted in the drawing, the mold 9 of the movable plate 6 is maintained at a curing temperature when the material resin is a thermosetting resin. Heated and maintained.

  The supply device 10 includes a thermosetting resin (for example, a phenol resin) fed from a hopper into the heating cylinder by rotating and retreating the screw 10c in a heating cylinder 10a having a heating means (not shown) on the outer periphery. And a filler composite material) are semi-melted, and set shots (for example, 1 to 2 shots) are weighed in the tip of the heating cylinder. After the measurement, the semi-molten resin is injected and filled into the mold table 11 by advancing the screw. During the injection filling, the mold clamping device 1 is in the mold open state.

  In the mold table 11, as shown in FIG. 2, the plate-like portion 13a is pressed by a filling pressure (for example, 95 Mpa or more) to expand the storage chamber 14, and the total amount of the measured semi-molten resin is supplied from the supply nozzle 10b to the supply path. 15 is stored in the storage chamber 14. This accumulation is repeated until the set accumulation amount is reached.

  When the storage amount reaches the set amount, the screw 10c is stopped at the forward limit position, and the tip of the heating cylinder is closed so that the semi-molten resin does not flow backward to the heating cylinder even when the storage chamber 14 is pressurized by the mold clamping force. In the mold clamping apparatus 1, the hydraulic cylinder 4 is operated simultaneously with the end of the supply, and the mold clamping ram 7 is extended to start the mold closing stroke. As a result, the movable platen 6 moves forward together with the die 9 and abuts the die 9 on the die 8 on the fixed platen side.

  Since there is a heat insulating space 19 between the mold 8 and the plate-like part 13a of the movable part 13, the movable plate 6 further moves the mold 8 forward after both the molds 8 and 9 are in contact with each other. As shown, the mold 8 is pressed against the plate-like portion 13a of the movable portion 13 through the heat insulating material 18 to complete the mold closing. At this time, the cavity 21 of the mold 9 becomes a cavity having a gate portion 8 a by the both molds 8 and 9, and the gate portion 8 a makes nozzle touch with the in-mold nozzle 17.

  Since there is no resistance to the movement of the movable platen 6 until the mold closing is completed, the hydraulic pressure in the hydraulic cylinder 4 does not increase, but after the mold closing time, the semi-molten resin in the storage chamber is moved to the movable platen. Therefore, the hydraulic pressure rises, and the stroke shifts to mold clamping of the molds 8 and 9 by a high pressure clamping force (for example, 1225 to 1750 kN). Further, after the mold closing time, the plate-like portion 13a of the movable portion 13 that receives the molds 8 and 9 receives the clamping force, so that the semi-molten resin in the storage chamber is pressurized by the plate-like portion 13a, The cavity 21 is filled from the in-mold nozzle 17 of the plate-like portion 13a through the gate portion 8a. When the semi-molten resin passes through the gate and enters the cavity 21, the viscosity decreases due to heating from the mold.

  The filling of the semi-molten resin by pressurization of the plate-like portion 13a is performed until the end of a preset mold clamping operation time. The high-pressure mold clamping of the molds 8 and 9 ends when the mold clamping operation time has elapsed, and the mold depressurization is performed while the molds 8 and 9 are in contact. Further, in order to form a heat insulation space 19 between the mold 8 and the heat insulating material 18, the mold clamping ram 7 is moved backward by about 2 to 6 mm. Meanwhile, in the cavity 21, the resin is thermoset by the mold 9 maintained at the thermosetting temperature. In the supply device 10, while the resin is thermoset and the mold is opened, the resin to be molded next time is melted and measured.

  When the resin in the cavity is sufficiently cured, the stroke is opened, and the mold clamping ram 7 moves backward to the original position. As a result, the molds 8 and 9 that are in a jointed state by the molded product made of the cured resin are separated from the plate-like material 13 a together with the movable plate 6 in a mold-closed state, and then the mold 8 is moved by the limiting plate 20. Only the mold 9 is moved while being restrained. As a result, the molds 8 and 9 are opened. The molded product leaves the mold 8 and remains in the cavity 21 due to the difference in contact area. After the mold is opened, the molded product is taken out.

  The joint maintenance when the molds 8 and 9 are opened is not shown in the figure, and is omitted in the figure. However, the connecting means such as a latch lock that is locked by a pressing force and unlocked by a tensile force is connected to both. The mold 8 may be provided on the parting surfaces of the molds 8 and 9 so that the mold 8 and the mold 9 can be opened and moved until the movement is restricted by the restriction plate 20.

  Next, the molding monitoring method of the present invention will be described with reference to the flowchart of FIG. First, when the storage amount of the semi-molten resin in the storage chamber 14 reaches the set amount, the pressure filling molding starts and the mold closing process is started.

  The mold 9 moves forward together with the movable plate 6 to close the mold 8, and further moves the mold 8 to contact the plate-like portion 13 a of the movable portion 13 of the mold base 11 through the heat insulating material 18. To. After the molds 8 and 9 are completely closed, the stored semi-molten resin is pressurized, and the hydraulic pressure in the mold clamping cylinder 4 is increased and the mold is clamped. The high pressure switching time when the mold is closed is the mold closing time (also the filling start time), and the time monitor reference value and upper and lower limit values are set for the movement time from the mold closing time until the mold speed falls below the specified speed. Keep it.

  If the time monitor is between the upper limit and lower limit values, the molded product is a non-defective product, the other is a defective product, and when the defective product is continuously generated and reaches the number of continuous stops, the cycle is completed and the molding machine is stopped. It is. For detection of the mold closing time, normally used detection means such as a position detection device such as a proximity switch, a photoelectric tube, an encoder, an oil pressure detector of a mold clamping cylinder, and a timer are used.

  When the mold closing time is detected, the measurement of the movement time from that time until the mold speed becomes a predetermined speed or less is started (step 31), and the movement speed is monitored (step 32). Timekeeping is terminated when the moving speed becomes a predetermined speed or less (step 33). If the moving time from the mold closing time to the end of mold clamping is outside the monitor width, it is determined that molding is defective (step 35), and if it is within the monitor width, it is determined that molding is good (step 36).

  FIG. 6 shows a method of monitoring the position of the closed molds 8 and 9 (referred to as “closed molds”) at the end of mold clamping as a filling completion position by a normal means. First, the completion of filling the semi-molten resin into the cavity 21 is determined from the mold clamping end position. The mold clamping end position is determined by the completion of timing of a preset mold clamping stroke time (steps 40 and 41). When the mold clamping process is completed, a control device (not shown) stores the position of the mold 9 (step 42).

  It is determined from the stored mold clamping end position whether or not the position of the mold closing molds 8 and 9 is within the monitor width (step 43). If it is outside the monitor width, it is determined as a defective product (step 44), and if it is within the monitor width, it is determined as a non-defective product (step 45). In the case of a non-defective product, it is determined whether or not the mold position has exceeded a plurality of correction values shown in FIG. 7 (step 46).

  In the case of a defective product, since the correction value is exceeded, the process proceeds to step 47. If the mold position is between + correction value 1 and -correction value 1, it is determined that the resin amount is an appropriate amount, and the resin amount for the next molded product is the same as the previous amount. -If the correction value is less than 1, the mold position is small (position where the movable part 13 approaches the fixed part 12), and it can be determined that a large amount of resin has entered the cavity 21, so the amount of resin for the next molded product is The correction amount is increased by 1 from the previous time (step 48). If the correction value exceeds 1 (step 49), the mold position is large (position where the movable part 13 is separated from the fixed part 12), and it can be determined that the resin contained in the cavity is small. Is reduced by the correction amount 1 (step 50).

  When the correction value 2 in the figure is provided, it is preferably a value that deviates more than the correction value 1 from the appropriate amount range. If it deviates greatly, it is necessary to correct the amount of resin in order to return it to an appropriate amount. Therefore, the correction amount 2 is preferably larger than the correction amount 1.

  As described above, by correcting the amount of resin according to the position of the mold closing molds 8 and 9 at the end of mold closing, when the resin viscosity or reactivity in the storage chamber changes, or when the resin is supplied into the heating cylinder Even when the density of the resin to be melted changes, an optimal amount of resin can be supplied at that time, and a molded product with stable quality can be obtained. Furthermore, by combining with molding defect monitoring, it is possible to detect a molded product that has become molding defect without being compensated by correction, leading to improved quality.

1 is a partially longitudinal side view of a pressure filling molding machine that can employ a molding monitoring method according to the present invention. It is a vertical side view at the time of mold opening of the mold apparatus for pressure filling molding. It is a vertical side view at the time of mold closing of a metallic mold device. It is a vertical side view at the time of completion | finish of mold clamping (at the time of filling completion) of a metal mold apparatus. It is a flowchart of the molding monitoring by moving time. It is a flowchart of the molding monitoring by a metal mold | die position. It is a correction amount discrimination diagram from the monitor width of the molding monitoring by the mold position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Clamping device 3 Fixed platen 4 Clamping cylinder 6 Movable platen 7 Mold clamping ram 8 Mold on the fixed platen side 8a Gate part 9 Mold on the movable platen side 10 Feeder 11 Mold base 12 Fixed part 13 Movable part 13a Plate shape Part 14 Reservoir 15 Supply path 17 In-mold nozzle 18 for filling 18 Heat insulation 21 Cavity

Claims (4)

The material resin is made into a semi-molten state by a supply device inside the screw, and after filling the semi-molten resin into a storage chamber of variable volume attached to the fixed plate from the supply device, the storage chamber side, the movable plate, By press-fitting the semi-molten resin in the storage chamber by clamping the mold attached to the mold, when filling the cavity from the nozzle in the mold provided in the storage chamber,
Set the monitor width for the moving time from the mold closing time until the mold speed becomes less than the predetermined speed, and if the moving time exceeds the monitor width, it will be molding failure and the resin pressure filling Mold monitoring method in molding.   2. The molding in pressure filling molding of resin according to claim 1, wherein the movement time starts from the time of mold closing or the time when the driving pressure of the moving means of the movable plate reaches a set pressure by mold closing. Monitoring method. The material resin is made into a semi-molten state by a supply device inside the screw, and after filling the semi-molten resin into a storage chamber of variable volume attached to the fixed plate from the supply device, the storage chamber side, the movable plate, By press-fitting the semi-molten resin in the storage chamber by clamping the mold attached to the mold, when filling the cavity from the nozzle in the mold provided in the storage chamber,
A molding monitoring method in pressure filling molding of resin, wherein a monitor width for a mold position at the end of mold clamping is set, and molding failure occurs when the mold position exceeds the monitor width.   The resin amount for the next molded product is corrected with a preset correction amount when the mold position at the end of mold clamping exceeds a preset correction value. 4. A molding monitoring method in pressure filling molding of the resin according to 3.

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