JP3281995B2 - Continuous plasticizing injection molding method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous plasticizing injection molding method and apparatus which are performed by an apparatus having a continuous plasticizing apparatus and an injection apparatus connected with or without an accumulator.

[0002]

2. Description of the Related Art Conventionally, in order to improve the efficiency of an injection molding machine, an accumulator is conventionally interposed as a buffer between continuous plasticization by a screw and an intermittent injection molding operation, and after injection without an intervening accumulator. Various types of continuous plasticization type injection molding apparatuses have been proposed in which a plasticizing apparatus is continuously operated by immediately storing a plasticized resin in the injection apparatus.

[0005] Generally, a molding start-up procedure at the start of operation of an injection molding apparatus is performed as follows. (1) Start from a short shot (about 90% resin filling rate in the mold) according to the provisionally set conditions. (2) The weighing stroke is gradually increased, and a transition is made to a full shot. (3) Correct molding conditions such as injection speed, pressure and time while observing products so that good products can be obtained. (4) When non-defective products are obtained, switch to automatic operation and perform continuous molding.

In the steps (1) to (3), usually, a manual operation for independently performing each operation such as mold closing, injection, pressure holding, cooling, metering, mold opening and product removal, or a series of these operations is performed. It is performed by semi-automatic operation performed as a cycle.

[0005] Such condition setting is generally performed by trial and error, in which a product is observed for each shot, and conditions necessary for obtaining a good product are changed. Not constant.

[0006] In a general injection molding apparatus, the screw stops rotating after the plasticized resin is measured, and does not rotate until the next measurement is performed, and is in a standby state. That is, plasticization does not proceed during this time. For this reason, a general injection molding apparatus does not cause much problem even when the interval of the injection operation is not constant as in the above-described molding startup.

[0007]

The continuous plasticizing type injection molding apparatus is characterized in that plasticizing is preferably performed by continuously rotating a preferably effective twin screw having a constant effective length, and thereby the plasticizing quality of the resin. Therefore, it is preferable to shift to continuous plasticization from the earliest possible point at the start-up, and to maintain this.

The present invention enables continuous plasticization as much as possible even when the balance between the amount of plasticized resin and the injection cycle is not maintained in a predetermined relationship at the time of starting the molding or during molding. It is an object of the present invention to provide a continuous plasticizing injection molding method and apparatus capable of promptly transitioning to a steady state.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a continuous plasticizing device for a synthetic resin material, and a direct or accumulator device interposed in an outlet of the continuous plasticizing device. A continuous plasticizing injection molding method using a continuous plasticizing type injection molding device having an injection device connected via a device, wherein during operation, a time-out issued when a preset molding cycle time is exceeded. By a signal or a cycle time extension signal by a driver, the amount of plasticized resin supplied from the continuous plasticizing device is reduced, and the accumulation time of the amount of plasticized resin is extended ,
Accumulator device accumulates plasticized resin normally
Or when it reaches the vicinity of one shot injection amount,
Plasticized resin sent from the plasticizer is discharged to the outside
I do .

[0010]

In addition, the accumulation time is extended as described above.
With, when the plasticized resin accumulation of the accumulator device exceeds the normal accumulation, increasing the plasticized resin extrusion rate from the accumulator device in response to the exceeding amount of
Good .

Furthermore, when the accumulated amount of the plasticized resin in the accumulator device exceeds the normal accumulated amount, the plasticizer supplied from the continuous plasticizing device according to the exceeded amount until the plasticized resin in the accumulator device is completely extruded. It is preferable to reduce the amount of the plasticized resin from the supply amount during the normal cycle operation.

Still further, the plasticized resin sent from the continuous plasticizing apparatus may be temporarily discharged to the outside by the time-over signal or the cycle time extension signal.

In this case, the supply amount of the plasticized resin from the continuous plasticizing device may be reduced, but it is preferable to keep the operating conditions of the continuous plasticizing device the same as in the normal cycle operation.

In order to achieve the above object, the present invention provides a continuous plasticizing device for a synthetic resin material, and a direct or accumulator device interposed in an outflow passage of the continuous plasticizing device.
Further, in a continuous plasticization type injection molding apparatus having an injection device connected via an opening / closing valve, a flow path of a plasticized resin from an outflow passage of the continuous plasticization device to a nozzle provided at a tip of the injection device. A resin removing device for discharging the plasticized resin is provided therein.

It is preferable that the resin removing device is configured so that the degree of opening of the flow path area can be adjusted.

[0017]

In operation, when a preset molding cycle time is exceeded and a time-over signal is issued or a cycle time extension signal is issued from the driver, the supply amount of the raw material feeder and the rotation speed of the screw are reduced. Then, the amount of the plasticized resin sent from the continuous plasticizing device is reduced, and the accumulation time of the plasticized resin in the accumulator device is extended. In this way, the shutdown of the continuous plasticizing device is minimized, while the necessary measures are taken.

During the treatment, when the accumulator device accumulates the normal accumulation amount smaller than the one shot injection amount or the plasticized resin close to the one shot injection amount,
When more storage, remains plasticized resin into the accumulator device in the next molding cycle, because were unfavorable to discharge the plasticized resin is fed from the continuous plasticator to temporarily outside.

Further, when the accumulated amount of the plasticized resin in the accumulator device exceeds the normal accumulated amount, the extruding speed of the plasticized resin from the accumulator device is increased in accordance with the exceeded amount, or the plasticized resin from the accumulator device is increased. Until the plasticized resin is extruded, it is preferable to secure the molding cycle time by reducing the amount of the plasticized resin supplied from the continuous plasticizing apparatus from the supply amount during the normal cycle operation according to the amount exceeding the above. .

Further, when the time-out signal or the cycle time extension signal is output, immediately or after the accumulated amount of the plasticized resin in the accumulator device reaches the regular accumulated amount or the one shot injection amount, the continuous plasticizing resin is discharged. The plasticized resin sent from the plasticizing device is discharged to the outside by a resin removal device provided in the flow path of the plasticized resin from the outflow path of the continuous plasticizing device to the nozzle provided at the tip of the injection device. Is also good.

At this time, if the amount of the plasticized resin sent out from the continuous plasticizing device is reduced, the amount of the resin discharged to the outside can be reduced. By adjusting and controlling the resin pressure, it is possible to suppress a change in the plasticizing condition at the time of removing the resin and immediately return to the steady operation.

[0022]

1 and 2 show an embodiment of the present invention.
This will be described with reference to FIG. Reference numeral 10 denotes a continuous plasticizing device, which comprises a plasticizing cylinder 11 having a heating and cooling device (not shown) and a plasticizing screw 12 engaged with the plasticizing cylinder. The plasticizing screw 12 is a two-axis screw that rotates in the same direction or different directions, and is rotated by a driving device 13. A first supply port 14 is opened near the base end of the plasticizing cylinder 11, and a synthetic resin material is supplied by a first raw material feeder 15. At a substantially central position in FIG. 1 of the plasticizing cylinder 11, a second supply port 16 is opened.
The raw material feeder 17 supplies reinforcing or filling materials such as glass fiber, carbon fiber, and mica. A vent port 18 is opened from the left side of the plasticizing cylinder 11 in FIG.

The plasticized resin outlet channel 19 opened at the tip of the plasticizing cylinder 11 is connected to an accumulator device 20. The accumulator device 20 includes a cylinder 21 and a plunger 22, and an accumulator chamber 23 is provided at a tip side (a lower end side in FIG. 1) of the plunger 22.
Is formed. The periphery of the accumulator chamber 23 is heated by a heater (not shown). A piston 26 of a drive cylinder 25 is connected to an upper end of the plunger 22 via a rod 24.

When the plunger 22 is at the forward limit position shown in FIG. 1, the accumulator chamber 23 is formed into an annular flow path 23a by the small-diameter projection 22a at the tip and the inner surface of the cylinder 21.
Is formed. The step 22b formed at the base of the small-diameter projection 22a of the plunger 22 is formed obliquely so that the side facing the outflow passage 19 of the continuous plasticizing device 10 is high and the side opposite thereto is low. Is in the forward limit position, the outflow passage 19 is
It is arranged to open below the highest position of b, that is, at the upper end of the annular flow path 23a.

Outflow channel 27 of accumulator device 20
Is connected to the injection device 30 via the first opening / closing valve 28. The injection device 30 is composed of an injection cylinder 31 heated by a heater (not shown) and an injection plunger 32 engaged with the injection cylinder 31. The injection resin 30 supplies plasticized resin supplied from the accumulator chamber 23 to the tip side of the injection plunger 32 (in FIG. It is stored in the weighing chamber 33 on the left end side). A piston 36 of an injection drive cylinder 35 is connected to a rear end of the injection plunger 32 via a rod 34. The measuring chamber 33 is connected to a nozzle 38 via a second opening / closing valve 37.

The upper chamber 25a of the drive cylinder 25 of the accumulator device 20 has a meter-in electromagnetic proportional flow control valve 42 when the first switching valve 41 is at the neutral position in the drawing.
It is connected to the tank 44 and the lower chamber 25b via a meter-out electromagnetic proportional pressure adjusting valve 43, and is released to the tank 44 while controlling the pressure of the upper chamber 25a as described later.
When the first switching valve 41 is switched to the right side b in FIG. 1, pressure oil controlled to a predetermined pressure by the first pressure reducing valve 46 from the hydraulic pressure source 45 is supplied via the electromagnetic proportional flow regulating valve 42. It has become so. The lower chamber 25b is opened to the tank 44 when the first switching valve 41 is switched to the b side, and is connected to the hydraulic power source 45 via the first pressure reducing valve 46 when the first switching valve 41 is switched to the a side. Is to be done. The on-off valve 47 is for temporarily stopping the advance of the plunger 22.

The rear chamber 35a of the injection drive cylinder 35 is connected to the tank 53 via the electromagnetic relief valve 52 when the second switching valve 51 is at the neutral position shown in FIG. When the switching valve 52a is in the illustrated switching position, the electromagnetic relief valve 52 controls the logic valve 52b with the set pressure of the pressure setting relief valve 52c, and when the switching valve 52a is switched to the side b opposite to that illustrated. The logic valve 52b is blocked. Further, when the second switching valve 51 is switched to the side b, the rear chamber 35a becomes the second pressure reducing valve 54.
Is connected to the hydraulic pressure source 55 via the.

When the second switching valve 51 is at the switching position on the side a, the front chamber 35b is connected via the electromagnetic proportional flow regulating valve 56 as the retreat speed control operating section of the injection plunger 32 and the second pressure reducing valve 54. And is connected to the hydraulic pressure source 55. A pressure gauge 58 is connected to the rear chamber 35a via a stop valve 57.

A resin pressure detector 61 and a resin pressure switch 62 are connected to the outflow passage 19 of the continuous plasticizing apparatus 10 and a position near the tip of the measuring chamber 33, and the former resin pressure is taken into the controller 63. When the latter resin pressure reaches a predetermined value to be described later, the contact is closed to generate a signal.

The accumulator device 20 includes S in FIG.
Detectors 70 to 74 for detecting the positions of the plungers 0 to S4 are provided, and these detection signals are taken into the controller 63 by a circuit (not shown).

The injection device 30 is provided with a detector 75 for detecting the measurement position of the injection plunger 32. The detector 75 is mounted so as to be position-adjustable so as to determine the metering completion position of the injection plunger 32 in accordance with the amount of resin of a molded product to be injection-molded.

The controller 63 controls the opening of the electromagnetic proportional flow regulating valve 56 so that the discharge pressure of the continuous plasticizing device 10 detected by the resin pressure detector 61 becomes the set value given to the setter 64. To control the retreat speed of the injection plunger 32, fetch signals from the detectors 70 to 74 provided in the accumulator device 20, and
4 to control the forward and backward speeds of the plunger 22 by controlling the opening of the electromagnetic proportional flow rate adjusting valve 42 and the electromagnetic proportional pressure adjusting valve 43 according to the set value of the first and second raw material feeders. The feed amounts 15 and 17 and the rotation speed of the plasticizing screw 12 are controlled.

Next, the continuous plasticizing injection molding method according to the present invention will be described with reference to FIGS. FIG. 2 is a diagram showing the basic operation relationship of the present apparatus.
Shows the operation of the plunger 22 during normal cycle operation,
The lower solid lines B1 to B5 show the operation of the injection plunger 32 during normal cycle operation.

Time t0 to t4 is one molding cycle time during normal cycle operation, t0 to t2 is cooling after injection, t2 to t3 is mold opening, product removal, mold closing, and t3 to t4 is molding time. This is an injection and pressure-holding step. In parallel with these steps, a measuring step from t0 to t2 and an accumulation step from t2 to t4 are executed.

As shown by the solid line A1, the plunger 22 of the accumulator device 20 moves at a predetermined speed (corresponding to the gradient of the solid line A1) from the normal accumulation position S1 toward the forward limit position S0 when the measurement of t0 is started. Down)
The plasticized resin in the accumulator chamber 23 is merged with the plasticized resin sent from the continuous plasticizing apparatus 10 and extruded into the measuring chamber 33.

From time t1 to t2 when the plunger 22 reaches the forward limit position, only the plasticized resin from the continuous plasticizing device 10 is supplied to the measuring chamber 33, and the injection plunger 32
Is retracted to the weighing completion position LS1 detected by the detector 75 provided corresponding to the piston 36, the first
The opening / closing valve 28 is closed, and the plasticized resin sent from the continuous plasticizing device 10 accumulates in the accumulator device 20. Due to this accumulation, the plunger 22 rises from the forward limit position S0 toward the normal accumulation amount position S1, as shown by the solid line A2.

For example, in the mold opening, product removal, and mold closing processes performed during this process, a preset molding cycle time is exceeded, a time-over signal is issued, or a cycle time extension signal is issued from the driver. Then, the controller 63 reduces the feed amount of the first and second raw material feeders 15 and 17 of the continuous plasticizing device 10 and reduces the rotation speed of the plasticizing screw 12 so that the plasticized resin sent from the continuous plasticizing device 10 is reduced. Decrease the amount.

When the time-over signal or the cycle time extension signal is output between t0 and t2, the continuous plasticizing apparatus 10 may be immediately decelerated as described above, but after reaching t1 or t2. You may make it decelerate.

Due to the deceleration of the continuous plasticizing device 10, the rise of the plunger 22 has a gentle gradient as shown by the dotted line a2 in FIG. 2, and the time to reach the normal accumulation amount position S1 is extended to t5. . During this time extension, the molding operation is returned or necessary measures are taken.

If the plunger 22 has reached the normal accumulation position S1 when the molding operation has not returned or the treatment has not been completed, the position when the plunger 22 reaches this position S1 or a position near the one-shot injection amount position S3 In S2, the first and second raw material feeders 15 and 17 and the plasticizing screw 12 are stopped, so that the plasticized resin exceeding the one shot injection amount is not accumulated in the accumulator chamber 23.

This is because when returning to the normal cycle operation, the plasticized resin is supplied from the accumulator chamber 23 to the measuring chamber 3.
This is because it is completely transferred to No. 3 and used for molding. By doing so, it is not necessary to perform an operation such as increasing the injection amount specially at the time of return and discharging it to the outside, and
It is possible to prevent the plasticized resin from remaining in the accumulator chamber 23.

When the plunger 22 exceeds the normal accumulation amount position S1, for example, at the plasticization stop position S2, as shown by a dotted line a1 in FIG. It is preferable that the extrusion speed be increased to reach the forward limit position S0 at t1, which is the molding cycle time of the normal cycle operation. Thereby, the operation can be smoothly returned without disturbing the molding cycle time.

Furthermore, as described above, the plunger 22
When increasing the extrusion speed, the supply amount of the plasticized resin from the continuous plasticizing device 10 is reduced according to the increase,
It is preferable to maintain the molding cycle time by setting the amount of the plasticized resin fed into the measuring chamber 33 during the period from t0 to t1 at the start of the measurement to be the same as in the normal cycle operation.

FIG. 3 shows another embodiment of the present invention, in which the amount of plasticized resin supplied from the continuous plasticizing device 10 is reduced, and the plasticizing from the continuous plasticizing device 10 is performed instead of stopping the supply. The resin is discharged to the outside by the resin removing device 80.

The resin removing device 80 includes a hole 81 provided in the cylinder 21 and opening to the accumulator chamber 23, a flow path 82 extending from the hole 81 to the outer surface of the cylinder 21, and a plasticized resin discharge portion outside the apparatus from the flow path 82. (Not shown) and the like, and a valve element 84 inserted into the hole 81 to open and close the flow path 82. The position of the valve element 84 is controlled by the driving device 85 so as to be continuous. While maintaining the resin pressure in the outflow passage 19 of the plasticizing device 10 at a predetermined value,
The plasticized resin is discharged to the outside. The pipe 83 is heated by a heater (not shown). The valve body 84 is formed so that the tip of the valve body 84 is aligned with the inner surface of the cylinder 21 so that the resin does not stay on the accumulator chamber 23 side.

The resin removing device 80 is preferably activated when the plunger 22 reaches the normal accumulation amount position S1 in response to a time-over signal or a cycle time extension signal, and removes the plasticized resin from the continuous plasticizing device 10 to the outside. Discharge. At the time of this discharge, it is preferable that the operation conditions of the continuous plasticizing apparatus 10 are not changed and a product of a predetermined quality is immediately obtained when the normal cycle operation is resumed. The amount of the activated resin may be reduced.

FIG. 4 shows an example of another resin removing device 90, in which the continuous plasticizing device 10, the accumulator device 2
0 and the injection device 30 are connected to each other by a three-way switching valve 91, and resin is removed by an on-off valve 92 capable of switching the three-way switching valve 91 and adjusting the flow rate.

The resin removing device is not limited to the above-described embodiment, but can be variously modified. It goes without saying that the installation location may be any of the resin routes from the outflow passage 19 to the nozzle 38. In addition, the present invention is also applicable to a continuous plasticizing injection molding apparatus having no accumulator device 20 as described above.

[0049]

As described above, according to the present invention, in a continuous plasticizing type injection molding apparatus, a continuous plasticizing apparatus and an injection apparatus are operated at a predetermined molding cycle time, for example, at the time of starting up molding. Even if it is not possible to do so, hold down the continuous plasticization device as little as possible,
The effect of being able to shift to the steady state and operate more quickly is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a continuous plasticizing injection molding apparatus to which the present invention is applied.

FIG. 2 is a basic operation relation diagram showing an example of the continuous plasticizing injection molding method of the present invention.

FIG. 3 is a partial sectional view showing another embodiment of the present invention.

FIG. 4 is a partial sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Continuous plasticizing device 12 Plasticizing screw 15 1st raw material feeder 17 2nd raw material feeder 19, 27 Outflow path 20 Accumulator device 22 Plunger 23 Accumulator room 28 First open / close valve 30 Injection device 33 Metering chamber 38 Nozzle 42, 56 Electromagnetic proportionality Flow control valve 43 Electromagnetic proportional pressure control valve 52 Electromagnetic relief valve 63 Controller 64 Setting device 70-75 Detector 80, 90 Resin removal device

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (8)

(57) [Claims] 1. A continuous plasticizer comprising a continuous plasticizing device for synthetic resin material and an injection device connected to an outlet of the continuous plasticizing device directly or via an accumulator device and further via an opening / closing valve. A continuous plasticization type injection molding method using an injection molding apparatus, wherein during operation, the continuous plasticization is performed by a time-over signal issued when a preset molding cycle time is exceeded or a cycle time extension signal by a driver. While reducing the amount of plasticized resin supplied from the device, extending the accumulation time of the amount of plasticized resin ,
Accumulator device accumulates plasticized resin normally
Or when it reaches the vicinity of one shot injection amount, continuous
Temporarily outside the plasticized resin sent from the plasticizer
A continuous plasticizing injection molding method characterized by discharging . 2. A continuous plasticizer for a synthetic resin material and a continuous plasticizer.
Directly or in the accumulator device at the outlet of the continuous plasticizer
Injection device connected via an open / close valve
Possible with continuous plasticizing injection molding equipment equipped with
It is a plastic injection molding method, which is set in advance during operation.
Time out issued when molding cycle time is exceeded
Signal or a cycle time extension signal from the driver.
Reduce the amount of plasticized resin supplied from the continuous plasticizer.
While increasing the accumulation time of the amount of plasticized resin,
When plasticizing resin accumulation of the accumulator device exceeds the normal accumulation amount, wherein the to that continuous plasticizing type injection molding method to increase the plasticized resin extrusion rate from the accumulator device in response to the exceeding amount of . 3. When the accumulated amount of the plasticized resin in the accumulator device exceeds the normal accumulation amount, the plasticization supplied from the continuous plasticizing device according to the exceeded amount until the plasticized resin in the accumulator device is extruded. 3. The continuous plasticizing injection molding method according to claim 1, wherein the amount of the resin is made smaller than the amount supplied during the normal cycle operation. 4. A continuous plasticizing device comprising a continuous plasticizing device for a synthetic resin material and an injection device connected directly to an outflow passage of the continuous plasticizing device or through an accumulator device and further via an on-off valve. A continuous plasticization type injection molding method using an injection molding device, wherein the plasticized resin sent from the continuous plasticizing device is temporarily discharged to the outside by the time-over signal or the cycle time extension signal. Continuous plasticization type injection molding method. 5. The continuous plasticizing injection molding method according to claim 4, wherein the amount of the plasticized resin sent from the continuous plasticizing device is reduced when the plasticized resin is discharged to the outside. 6. The continuous plasticizing type injection molding method according to claim 4, wherein the operating conditions of the continuous plasticizing device are kept the same as during the normal cycle operation when the plasticized resin is discharged to the outside. 7. A continuous plasticizing device comprising a continuous plasticizing device for synthetic resin material and an injection device connected directly or through an accumulator device to an outflow passage of the continuous plasticizing device, and further connected via an opening / closing valve. In the injection molding apparatus, a resin removal device for discharging the plasticized resin is provided in a flow path of the plasticized resin from an outflow path of the continuous plasticizing apparatus to a nozzle provided at a tip of the injection apparatus. Continuous plasticizing injection molding equipment. 8. The continuous plasticizing injection molding apparatus according to claim 7 , wherein the resin removing device is configured to be able to adjust an opening degree of a flow path area.