JPH11320610A - Resin material feeding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently deaerate a resin material fed to a plasticizing device and to rapidly feed a resin material without removing a resin material, feeding apparatus when a material and color are changed or molding of a resin wherein deaeration is unnecessary is performed. SOLUTION: A resin material feeding apparatus for feeding a resin material to a plasticizing device and deaerating it is provided with a feeding and deaerating device 10, a vacuum suction device and a control means and the feeding and deaerating device 10 is provided with the first shutter 21 and the second shutter 22 on its upper end part and its intermediate part and the first chamber 31 between two shutters performs quantitative cutout of the resin material and the second chamber 32 below the second shutter 22 is provided with a suction hole communicating with a vacuum suction device, a pressure switch and a level sensor and the control means controls feeding and deaerating of the resin material in the feeding and deaerating device 10 in relation to the plasticization operating condition of a molding machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin material supply device for an injection molding machine, and more particularly, to a method for plasticizing a resin material supplied to a plasticizing chamber of a plasticizing device for plasticizing a resin material by a plasticizing screw. The present invention relates to a resin material supply device that sucks and degasses.

[0002]

2. Description of the Related Art In a screw pre-plastic injection molding machine, a plasticizing screw is provided in a plasticizing chamber of a plasticizing apparatus, an injection plunger is provided in an injection chamber of an injection apparatus, and a connecting section for communicating the plasticizing chamber with the injection chamber. A passage is provided between the plasticizing device and the injection device. The thermoplastic resin material (hereinafter, referred to as resin) supplied from the hopper to the plasticizing chamber is kneaded and melted by rotation of the plasticizing screw and heating of the plasticizing chamber (hereinafter, referred to as plasticizing), and the molten resin is melted. Is pressure-fed from the communication passage to the injection chamber, and the plasticization amount of the resin is measured. The injection plunger then advances and the resin is injected into the mold cavity. In an in-line screw injection molding machine, plasticization is performed similarly, except that the screw is retracted.

[0003] If the plasticized resin contains air or moisture, the molten resin may be discolored or deteriorated depending on the resin. There are also resins in which monomers are generated during plasticization. For this reason, the measurement of the plasticized resin and the filling amount of the injected resin vary substantially (the weight varies), and the surface of the molded product is called a silver streak along with the flow of the resin filling. The quality of the product may be impaired due to the occurrence of streaks.

[0004] Therefore, there has been proposed a material supply device for sucking (hereinafter, referred to as degassing) water and air from a resin by a vacuum suction device and discharging the same. For example, JP-A-6-23
No. 815 proposes a material supply device that directly degass from a cylindrical portion below a hopper. 6-648
No. 38 proposes a deaerator in which a material supply section below a hopper is divided by one slide shutter and vacuum suction is performed. Further, Japanese Unexamined Patent Publication No. 9-1645
No. 27 proposes a resin material supply device in which a rotary resin material supply device is provided immediately below a hopper, and a storage cylinder below the hopper is continuously degassed.

[0005] However, there is a case where a large vacuum pump is required due to a relatively large degassing volume, or a dedicated machine is required due to a large mounting portion of a hopper. Further, practically, the airtightness of the resin material supply device may not be easily maintained. On the other hand, JP-A-8-20704
No. 8 proposes a material supply device for degassing a resin and preventing the resin from being degraded by an inert gas.
However, it is still insufficient as an injection molding machine that performs only vacuum degassing.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention can efficiently degas the resin supplied to the plasticizing chamber, and can perform degassing when changing materials or changing colors. When performing molding of resin that does not require the need for removing the resin material supply device, the resin in the hopper can be quickly supplied to the plasticizing chamber simply by performing a simple switching operation first. It is an object of the present invention to provide a resin material supply apparatus capable of supplying the resin material.

[0007]

Means for Solving the Problems 1) A resin material supply device for solving the above-mentioned problems is a resin material supply device for degassing a resin material to be supplied to a plasticizing chamber of a plasticizing device. Supply deaerator, a vacuum suction device, and control means for controlling them and controlling the control device of the molding machine, and the supply deaerator has an upper end portion. A first shutter and a second shutter, respectively, in a middle part and a first shutter. A first chamber divided by the first shutter and the second shutter temporarily stores the resin material and performs a constant cutout of the resin material. A second chamber below the second shutter, a suction hole communicating with the vacuum suction device for degassing the resin material dropped from the first chamber, a pressure switch, and a level for detecting a remaining amount of the resin material. With sensor It is characterized by having.

[0008] 2) When the control means of the resin material supply device for solving the above problem receives a signal indicating a decrease in the remaining amount of resin from the level sensor, the control means supplies the resin material until the injection molding machine completes plasticization. When starting to supply the resin material without waiting, a signal for inhibiting the plasticization of the molding machine is output to the control device of the molding machine, and the degassing is interrupted before the resin material in the first chamber falls. After that, the degassing of the resin material in the second chamber is resumed, and when the degassing is completed,
After outputting a signal permitting the plasticization of the molding machine to the control device of the molding machine, it is controlled to temporarily store the resin material in the first chamber.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 4, a plasticizing cylinder 3 is attached to the front (left side in the figure) of a base 2 of a plasticizing device 1 of a screw prepra type injection molding machine.
The distal end is connected to an injection device (not shown), and the rear end is inserted into a mounting hole penetrating through the base 2. Further, a band heater 4 is wound around the outer periphery of the plasticizing cylinder 3, and the plasticizing screw 5 is rotatably accommodated in a plasticizing chamber 3 a which is an inner hole of the plasticizing cylinder 3 so as to be able to advance and retreat. A hydraulic cylinder 7 containing a hydraulic piston 6 is connected to the rear end of the base 2, and a hydraulic motor 8 is connected to the rear end. The rear end of the plasticizing screw 5 is connected to the hydraulic piston 6 via a spline 5s, and the output shaft 8a of the hydraulic motor 8 is connected to the hydraulic piston 6 via a spline 8s. In such a screw prepra injection molding machine, the hydraulic oil supplied to the oil chambers before and after the hydraulic piston 7 is switched, and the plasticizing screw 5 is changed.
Moves back and forth by a small distance. That is, in the plasticizing step, the plasticizing screw 5 is retracted so that the plasticizing chamber 3a communicates with the injection chamber, and in the injection step, the plasticizing screw 5 advances and the communication between the two is closed. ing.

On the upper part of the base 2, a supply deaerator 10 described later is mounted together with a well-known standard hopper 80. A mounting seat 2a to which the supply / deaeration device 10 is connected is formed at the upper part of the base 2. Material supply holes 2h, 3h penetrating from the mounting seat 2a to the base 2 and the plasticizing cylinder 3 are formed. ing. Of course, the dimensions of the mounting seat 2a are formed so that the standard hopper 80 can also be mounted.

The plasticizing screw 5 has a material supply hole 3h.
A well-known plasticizing screw groove 5a is formed in a range from a position facing the front end to the front end. In a predetermined range rearward from a position facing the rear end position of the material supply hole 3h, a short pitch, shallow groove sealing screw groove 5b is formed in the same screw direction as the plasticizing screw groove 5a. I have. Further behind and in front of the spline 5s, a round bar-shaped sealing surface 5 is provided.
c is formed. On the other hand, a hole for attaching a seal is formed in the rear end face of the base portion 2, and a plasticizing screw 5 is provided here.
The seal 9 slidingly contacting the seal surface 5c is fixed.

In the plasticizing apparatus 1 configured as described above,
From the hopper 80, the supply deaerator 10, the material supply hole 2h,
3h, the resin supplied to the plasticizing chamber 3a is heated by the band heater 4 of the plasticizing cylinder 3 and the plasticizing screw 5a.
Plasticized by the rotation of At this time, before the resin is plasticized, the resin is degassed by a supply deaerator 10 described later, and air, moisture, monomers, and the like are sucked. Further, the resin hardly leaks from the seal 9.
The resin to be leaked is sucked toward the material supply holes 2h and 3h by the supply and deaeration device 10, and further the sealing screw 5
This is because the resin does not easily move backward due to the labyrinth effect and the forward feeding effect of b. In this screw prepra injection molding machine, the plasticizing screw 5 advances and retreats only a short distance only at the start or at the end of the plasticizing step. Therefore, the time during which the plasticizing screw 5 simultaneously performs the rotation operation and the axial movement operation with respect to the seal 9 is short,
There is an advantage that the wear of the seal 9 is small because the rotation time is simply longer.

The supply and deaerator 10 is configured as shown in FIGS. 1, 2 and 3 with a partial sectional view. 1 is a side view, FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a plan view of FIG. 1 as viewed from above. The supply and deaeration device 10 includes a first shutter 21 attached to an upper end and a second shutter 22 attached to an intermediate portion.
The space between the first and second shutters 22 is the first chamber 31
The space below the second shutter 22 can be divided by the respective shutters 21 and 22 as a second chamber 32.

The details will be described below.
Guide frames 15, 16 that guide the robot forward and backward with the
The upper and lower cylinders 11 and 12 are arranged, and the lower cylinder 12 is formed of a transparent material. Cylinder 11
The flange 1 is provided at the upper end of the
3 and 14 are arranged, and have a shape corresponding to the mounting seat of the hopper 80 and the mounting seat 2a of the base 2, respectively. On the lower surface of the upper end flange 13, a guide frame 1 for guiding the first shutter 21 so as to be able to advance and retreat with the first shutter 21 sandwiched from above and below
7, 18 are attached. Upper and lower flanges 13,
Between the fourteen, four tie bars 19 are mounted, which penetrate the guide frames 17, 18, and 15,16. The tie bar 19 is connected to the upper and lower flanges 13 and 1.
By tightening the cylinders 11 and 12 with 4,
The supply and deaerator 10 is integrally assembled.

A bracket 23 is fixed to the upper guide frames 17, 18 and the intermediate guide frames 15, 16, and a first air cylinder 24 for moving the first shutter 21 forward and backward is provided on the bracket 23.
And a second air cylinder 25 for moving the second shutter 22 back and forth
And are attached. And, each cylinder 24, 2
5 rods are connected to the shutters 21 and 22.
Further, direction switching valves 26 and 27 for respectively moving the cylinder rods of the air cylinders 24 and 25 forward and backward are mounted in the middle of the respective air pipes, and compressed air is supplied from a compressed air supply device not shown. I have. Also, the shutters 21 and 22 and the upper and lower guide frames 17 and 1 are provided.
8, 15, and 16 are formed with through holes 20 of substantially the same shape for dropping the resin, respectively.
When the shutters 21 and 22 advance and retreat, the through holes 20 relatively move, and
The configuration is such that the first and second components are opened and closed. Of course, the through hole 20 is substantially the same as the inner diameter of the cylindrical bodies 11 and 12.

A level sensor 41 is attached to the lower flange 14 at a position close to the second chamber 32. The level sensor 41 detects a decrease in the resin level in the second chamber 32, that is, a remaining amount of the resin.
For example, a capacitance type proximity switch that detects a change in capacitance that changes due to the presence of resin, a photoelectric tube detector that detects the presence of resin by light, and the like can be used. The lower guide frame 16 on the lower side of the second shutter 22 is provided with two through holes communicating with the second chamber 32. One of the through holes is provided as a suction hole 16a to the vacuum suction device 50. A pipe is provided so as to communicate with the pipe, and an opening / closing switching valve 51 for switching between opening and closing of the pipe is provided in the middle of the pipe. A pressure switch 52 is attached to the other through hole 16b.

As shown in FIG. 5, the above directional control valve 2
6, 27, an open / close switching valve 51 and a vacuum suction device 50, a control means 60 for receiving detection signals from the pressure switch 52 and the level sensor 41, and performing necessary input / output with the control device 70 of the injection molding machine. Control device 70 for molding machine
, Or provided separately.

The control means 60 includes at least a processing unit 61 and a control unit 62. The processing unit 61 receives a signal indicating whether the pressure switch 52 has reached a predetermined pressure and a signal indicating whether the level switch 41 has detected a decrease in the resin level.
From 0, a command for starting or ending the molding operation, a command for starting or stopping the supply of the resin, and an output signal during execution of plasticization are taken in. Also, a purge command or a command for a molding operation without degassing is taken in. Further, the processing unit 61 outputs a signal indicating that the resin is being supplied or is being supplied or an error signal to the control device 70 as described later. On the other hand, the control unit 62 controls the direction control valves 26 of the first air cylinder 24 and the second air cylinder 25,
The switching of the valve 27 and the open / close switching valve 51 and the start or stop of the vacuum suction device 50 are controlled. The control means 6
The zero processing unit 61 and the control unit 62 may be incorporated in the control device 70.

The resin material supply device having the above-described configuration is
According to the flowcharts shown in FIGS. 6 and 7, the resin is supplied and degassed. The flowchart is divided into the first half shown in FIG. 6 and the second half shown in FIG.

First, a state before the supply of the resin is started will be described. Before starting the operation of the molding machine, the resin remaining in the previous molding operation is purged, and each chamber 3 is purged.
It is assumed that no resin remains in the first and second shutters 32, the first and second shutters 21 and 22 are closed, and the resin is supplied to the hopper 80 in this state. In the above state, after the control means 60 receives the molding operation start signal and the supply command from the control device 70, the resin is supplied as follows.

First, after the vacuum suction device 50 is started,
The open / close switching valve 51 is opened, and the decompression of the second chamber 32 is started (S1). After a predetermined time has elapsed (S2), the first shutter 21 is opened (S3), and the resin of the hopper 80 falls on the second shutter 22. After a lapse of a predetermined time (S4), the first shutter 21 is closed (S4).
5) A predetermined amount of resin corresponding to the volume of the first chamber 31 is cut. Next, the processing unit 61 checks the amount of resin in the second chamber 32 based on the detection signal of the level sensor 41 (S6). At first, because there is no resin, naturally proceed to the next step, whether the plasticizing screw 3 is rotating,
That is, the processing unit 61 determines whether or not the plasticization is being performed based on the presence or absence of the output of the control device 70 during the plasticization (S7). Since no resin is present in the plasticizing chamber 3a at first, the plasticizing is not performed naturally, and the process proceeds to the next step.

Before starting the supply of the resin, the processing section 61 outputs a supplying signal to the control device 70 of the injection molding machine (S
8) The controller 70 can prohibit the next plasticization until a supply completion signal described later is received. Then, the processing unit 61 of the control means 60 initializes variables n and m, which will be described later, to 0 (S9), the control unit 62 closes the open / close switching valve 51 to interrupt the deaeration (S10), and activates the second shutter 22. Open the resin in the first chamber 31
2 (S11). Thereafter, the processing unit 61 adds 1 to the variable n and stores that the first resin supply has been performed (S12). After a lapse of a predetermined time (S1
3), the processing unit 61 detects a decrease in the resin level by the level sensor 41 and determines the remaining amount of the resin (S1).
4). If the resin has fallen normally, the presence of the resin is detected, and the routine goes to the next step S15. Step S1
0, the deaeration is interrupted because the falling or jumping resin powder is sucked into the suction holes 16a,
This is to prevent c from being clogged.

If the resin in the first chamber 31 does not fall, no resin presence signal is output from the level sensor 41 (S14). At this time, in most cases, the resin has caused a bridge phenomenon.
2 is opened and closed several times, and an impact is applied to the supply deaerator 10 (S32). This is because the resin falls in most cases. Then, the shutter 22 is opened (S3), and the flow from steps S4 to S14 is executed again. The number of times of re-execution is limited by the processing unit 61 comparing the preset allowable number N with the variable n (S31). If the resin does not drop even if the predetermined number N is exceeded, error processing is performed. , An abnormal signal is sent to the control device 70 of the molding machine (S33).

When the processing section 61 confirms that the resin has dropped normally (S14), the second shutter 22 is closed (S15), and deaeration is resumed (S16). Then, the processing unit 61 adds 1 to the variable m and stores that the first deaeration has been performed (S17). After a lapse of a predetermined time (S1
8), the processing unit 61 detects whether or not the pressure in the second chamber 32 has decreased to a predetermined value by the pressure switch 54, thereby determining the completion of the pressure reduction (S1).
9). If the pressure in the second chamber 32 is reduced to the predetermined pressure, the processing unit 61 outputs a supply completion signal (S2).
0). Upon receiving the supply completion signal, the control device 70 of the molding machine permits the plasticizing operation, and the injection molding operation is started. At this time, degassing of the resin is continuously performed,
The resin in the material supply holes 2h, 3h and the plasticizing chamber 3a in the vicinity thereof as well as in the second chamber 32 is degassed.

When the pressure in the second chamber 32 is not reduced (S19), in most cases, the resin is caught and the second
Shutter 22 is not fully closed. Therefore, the processing unit 61
Closes the open / close switching valve 51 to interrupt the deaeration (S35),
The control unit 62 opens and closes the second shutter 22 several times (S36), closes the shutter 22 (S15), and re-executes the flow from step S16 to S19. The number of times of re-execution is limited by the processing unit 61 comparing the preset allowable number M and the variable m (S34). If the pressure does not decrease even if the predetermined number M is exceeded, an error process is performed. , An abnormal signal or the like is sent to the control device of the molding machine (S37). The deaeration is interrupted in step S35 for the same reason as in step S10.

When the supply completion signal is output (S20),
Next, the processing unit 61 determines whether or not the supply of the resin is necessary. If there is no command to stop the supply from the control device 70 (S21), the process returns to step S3 to return to the first shutter 2 again.
1 is opened. Normally, a supply stop command is not issued until the injection molding operation is about to end, so steps S3 to S21 are performed until the supply stop command is issued.
The flow up to the above is repeated, and the quantitative cutout of the resin and the supply and deaeration of the resin are repeated as follows.

After the first shutter 21 is opened again (S
3) After a lapse of a predetermined time (S4), the first shutter 21 is closed, and a predetermined amount of resin corresponding to the volume of the first chamber 31 is cut again (S5). And the second chamber 3
2 is again confirmed as described above (S
6) In this case, since the resin is already supplied, the presence of the resin is detected. Then, the processing unit 61 waits without starting the next resin supply until the plasticization is repeatedly executed and the amount of resin decreases. When it is detected that the remaining amount of the resin has dropped below the predetermined level (S6), the processing unit 61 determines again whether or not the plasticizing process is being performed. Also in this case, since the molding operation has already been started, plasticization may be in progress. Therefore, the processing unit 61 waits until the plasticization being performed is completed, that is, until the output of the control device 70 during the plasticization is exhausted (S
7). When the plasticization is completed, the process proceeds to the next step, and the subsequent steps S8 to S21 are performed as described above.

After the molding operation is approaching the end, or after a resin supply stop command is output from the control unit 70 to the processing unit 61 due to other circumstances, the processing unit 61 proceeds to step S21.
Is determined (21), the flow from step S3 to S21 is no longer performed. And
Until the processing unit 61 receives the molding operation end signal from the control device 70, degassing of the resin remaining in the second chamber 32, the material supply holes 2h, 3h and the plasticizing chamber 3a in the vicinity thereof is continued, and the injection molding is continued. Is done. Thereafter, when the processing unit 61 receives the molding operation end signal from the control device 70 and recognizes it (S22), the control unit 62 closes the open / close switching valve 51 and stops the vacuum suction device 50 to stop deaeration. (S23).

As described above, the resin is supplied and degassed. In the present invention, the resin is supplied without significantly delaying the interval between the plasticizing steps of the molding machine. This is because when the resin in the first chamber 31 is supplied to the second chamber 32, the resin falls quickly from the opened second shutter 22. Furthermore, plasticization can be already performed before the resin is quantitatively cut into the first chamber 31.

Further, since the deaeration efficiency is high, a small vacuum deaerator is sufficient. Except when the second shutter 22 is opened and the resin falls, the volume to be decompressed is
This is because there are only two small volumes. Since the first shutter 21 is closed when the second shutter 22 is opened, the reduced pressure of the second chamber 32 does not greatly increase at this time. Therefore, it should be noted that the efficiency of degassing is hardly reduced at this time.

When purging for resin change or the like,
When forming without degassing, the supply deaerator 10 is controlled according to a flowchart as shown in FIG. The processing unit 61 of the control means 60 executes the purge command or
When receiving the command of the molding operation without degassing from the control device 70, the control means 60 outputs a signal during supply and then outputs the signal (S
51) Open the two shutters 26 and 25 sequentially (S
52, S53), after the resin of the hopper 80 can always be supplied to the plasticizing chamber 3a, a supply completion signal is output to the control device 70 (S54). In response to this, the molding machine starts a molding operation without purging or degassing. In this case, it goes without saying that the vacuum suction device 50 has not been activated. As described above, the resin in the hopper 80 falls quickly only by first opening the two shutters 26 and 25, and thereafter the resin is supplied to the plasticizing chamber 3a without any operation every time the resin is supplied. Therefore, there is no need to remove the resin supply device of the present invention.

[0032]

As described above, according to the present invention, even when only the small-capacity second chamber 32 divided by the second shutter is degassed during the interruption of the plasticizing step, the plasticizing step is performed thereafter. Since only the second chamber 32 is degassed, degassing is performed efficiently. In addition, the fixed amount cutting of the resin can be performed during the plasticization, and the supply of the resin is performed promptly by opening the second shutter and falling, so that the interval of the plasticizing step is rarely delayed.

Further, in the case of material change or color change, the resin in the hopper 80 can be quickly dropped and supplied by simply opening the first shutter 21 and the second shutter 22 first. In addition, since there is no need to operate the resin material supply device during material change or color change, purging can be quickly completed. Therefore, there is no need to remove the resin material supply device when changing materials or changing colors.

Also, when molding resin that does not need to be degassed, the resin in the hopper 80 is quickly dropped and discharged simply by opening the first shutter 21 and the second shutter 22 first. Therefore, there is no need to remove the resin material supply device.

[0035]

[Brief description of the drawings]

FIG. 1 is a side view showing a partial cross section of a supply and deaeration device according to the present invention.

FIG. 2 is a side view showing a right side surface of the supply and deaeration device shown in FIG.

FIG. 3 is a plan view showing an upper surface of the supply and deaerator shown in FIG.

FIG. 4 is a sectional view showing a main part of the plasticizing device.

FIG. 5 is a block diagram of devices related to a control unit of the resin material supply device.

FIG. 6 is a flowchart showing the first half of the deaeration operation of the resin material supply device.

FIG. 7 is a flowchart showing the latter half of the deaeration operation of the resin material supply device.

FIG. 8 is a flowchart showing a purge operation or an operation without degassing of the resin material supply device.

[Explanation of symbols]

 1: plasticizing device 2: base of plasticizing device 3: plasticizing cylinder 3a: plasticizing chamber 10: supply and deaerator 16a: suction hole 21: first shutter 22: second shutter 31: first chamber 32: first 2 chamber 41: Level sensor 50: Vacuum suction device 52: Pressure switch 60: Control means 70: Control device of injection molding machine 80: Hopper

Claims (2)

[Claims] 1. A resin material supply device for degassing a resin material to be supplied to a plasticizing chamber of a plasticizing device, comprising: a supply degassing device disposed between a hopper and the plasticizing device; Control means for controlling the supply and deaeration device and the vacuum suction device and for controlling the control device of the injection molding machine, wherein the supply and deaeration device has an upper end portion of the supply and deaeration device. A first shutter and a second shutter, respectively, at a middle portion and a first shutter. The first chamber, which can be divided by the first shutter and the second shutter, temporarily stores the resin material and performs a fixed amount cutout of the resin material. A second chamber below the second shutter, a suction hole communicating with the vacuum suction device for degassing the resin material dropped from the first chamber,
A resin material supply device comprising: a pressure switch; and a level sensor for detecting a remaining amount of the resin material. 2. When the control means receives a signal indicating a decrease in the remaining amount of resin from the level sensor, the control means waits without starting supply of the resin material until the injection molding machine completes plasticization, and waits for the resin material. When the supply is started, a signal for inhibiting the plasticization of the molding machine is output to the control device of the molding machine, and after the deaeration is interrupted, the resin material in the first chamber is dropped. Resume the degassing of the resin material in the two chambers, and when the degassing is completed, output a signal allowing plasticization of the molding machine to the control device of the molding machine, and then put the resin material in the first chamber. 2. The resin material supply device according to claim 1, wherein control is performed such that the resin material is temporarily stored.