JPH09225964A - Injection molding machine capable of automatically setting material-feed amount and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a suitable feed amount of a material to a heating cylinder of a molding machine irrespective of a kind of the material. SOLUTION: A feed screw rotational frequency is set at n=X% (S12). It is rotated by driving, and a material is fed to a heating cylinder. A main screw is rotated by driving, the material fed in the heating cylinder is conveyed to in front of the heating cylinder while it is plasticized. After the main screw is retreated to start weighing, when material filling confirmation signal is outputted in the first place, drive times of the main screw and the feed screw are started to be sampled to obtain Tm, Tf by integrating (S13). A ratio of total values of driving times Tm and Tf is multiplied by a set factor Y and a rotational frequency (n) of the feed screw to operate a rotational set value nf of the feed screw (S19). The nf is made a rotational frequency set value of the feed screw (S20).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine capable of automatically setting a raw material supply amount and a method therefor, and particularly, in an injection molding machine for supplying a raw material to an injection mechanism by a raw material supply device, The present invention relates to an injection molding machine capable of automatically setting a raw material supply amount for setting an appropriate amount of raw material supplied to an injection mechanism and a method thereof.

[0002]

2. Description of the Related Art An injection mechanism of an injection molding machine rotates a screw provided in a heating cylinder to plasticize a raw material supplied into the heating cylinder. In the injection mechanism of such an injection molding machine, a hopper is provided at the raw material supply port of the heating cylinder, and the raw material stored in the hopper is fed into the heating cylinder by natural fall, and the raw material is supplied to the raw material supply port of the heating cylinder. Some have a raw material supply device for supplying while controlling. A general raw material supply device includes a feed cylinder, a feed screw inserted into the feed cylinder, and a rotation driving unit that rotationally drives the feed screw. By rotationally driving the feed screw, the raw material is supplied. Is fed from the hopper storing the above to the inside of the feed cylinder and supplied to the heating cylinder through the communication passage.

By the way, in the case of controlling the supply of the raw material into the heating cylinder by the raw material supply device, when the raw material supply amount is insufficient, the plasticizing amount corresponding to the rotation speed of the main screw cannot be obtained. Therefore, the molding cycle may be extended to cause a loss, and a surging phenomenon may occur in which the retreat of the main screw is temporarily stopped, which may cause defects such as burning and burrs in the molded product. On the contrary, when the raw material supply amount is excessive, the rotation torque of the main screw becomes high, and the rotation may become impossible. Further, since the raw material fills the main screw and the raw material dropping port, degassing of gas or the like generated during plasticization of the raw material is hindered, which may cause defects such as clouding of the surface of the molded product or silver streak. In addition, the inclusion of water or gas may cause a decrease in the strength of the molded product, which may be a cause of poor physical properties. Also,
Even if the plasticized raw material in the heating cylinder is not consumed for some reason, the raw material supply amount becomes excessive, resulting in the same problem as described above.

As a conventional raw material supply device for preventing such an excessive supply of raw material, Japanese Utility Model Publication No. 4-36254.
As disclosed in Japanese Unexamined Patent Application Publication (hereinafter referred to as "prior art 1"), a level detecting means for detecting the accumulated amount of the raw material is provided in a raw material supply passage communicating with the raw material supply port of the molding machine, and a predetermined level is provided. It is known that when the raw material is accumulated, a signal is issued from the level detecting means to stop the rotation of the feed screw so as to stop the supply of the raw material.

[0005] In addition, registered utility model No. 3012320 (hereinafter, referred to as Utility Model No. 3012320) for monitoring the feed failure of the raw material in the screw and stopping the supply of the raw material to avoid an abnormality.
(Refer to Prior Art 2), a reflection type level detector is arranged on the upper surface of a cylinder into which a feed screw is inserted, above the raw material dropping port so that the main screw is desired. It is known that the feed screw rotation command is turned off when the level of the raw material detected by the vessel is continuously higher than the preset value set by the level setter during the set time of the timer.

Further, as a conventional raw material feeding device for feeding a proper amount of raw material to a molding machine, there is an actual Japanese Utility Model Publication 54-35.
As disclosed in Japanese Patent Laid-Open No. 775 (hereinafter, referred to as Prior Art 3), a level detection device such as a level switch is provided in a feed passage for a raw material that communicates a metering feeder and a main screw, as in the case of Prior Art 1. It is known that the metering feeder is stopped by detecting the level of the raw material staying in the passage.

Furthermore, as a conventional technique for automatically setting the supply amount of the raw material, an injection molding machine disclosed in Japanese Patent Laid-Open No. 4-90324 (hereinafter referred to as Prior Art 4) is known. This prior art 4 sets the amount of material falling per unit rotation of the feed screw, the number of rotations of the feed screw, the number of rotations of the main screw and the amount of material feed per unit rotation as control data, and based on these control data. The number of rotations of the feed screw corresponding to the number of rotations of the main screw is calculated to control the rotation of the feed screw.

[0008]

However, in the above-mentioned prior arts 1 and 2, by detecting that the raw material has reached a predetermined level, and simply stopping the supply of the raw material to the heating cylinder, It prevents the overflow of raw materials.

Further, in the above-mentioned prior art 3, the level of the raw material staying in the supply passage is detected to stop the metering feeder, that is, the metering feeder is driven ON / OFF. It was not possible to set the supply amount of various raw materials.

Further, in the above-mentioned prior art 4, for each of the main screw and the feed screw, it is necessary to set and input the raw material supply amount per one revolution as a coefficient for each raw material to be used, and to perform the calculation. There was a problem that the content to do was complicated. In addition, when the plasticized raw material in the heating cylinder is not consumed for some reason and the raw material supply amount becomes excessive as a result, it is necessary to correct the raw material supply amount set by calculation. was there.

Furthermore, in the above-mentioned prior arts 1, 3 and 4, since the raw material supply passage communicating with the raw material supply port of the molding machine is provided with the detector for detecting the level of the raw material. , The level of the raw material in the immediate vicinity of the screw cannot be detected, and moreover, since the supply of the raw material is immediately controlled based on the signal detected from the detector, the level of the raw material cannot be accurately detected, There was a problem that the control was not stable.

The present invention has been made in view of the above problems, and can set an appropriate raw material supply amount to a heating cylinder of an injection molding machine regardless of the type of raw material, and can automatically set the raw material supply amount. It is an object to provide an injection molding machine and a method thereof.

[0013]

In order to achieve the above-mentioned object, the features of the invention relating to the injection molding machine capable of automatically setting the raw material supply amount are the main screw inserted into the heating cylinder and the main screw. An injection mechanism having a rotation drive means for rotationally driving the main screw around an axis and an injection drive means for axially driving the main screw; a feed cylinder; and a feed screw fitted in the feed cylinder. When,
A raw material supply device for supplying a raw material to the injection mechanism, and a predetermined upper limit value and a lower limit value of the raw material in the raw material supply port of the heating cylinder. When a level sensor that detects that the value level has been reached and that the level of the raw material in the heating cylinder is continuously higher than the upper limit for a predetermined time or more, the raw material filling confirmation signal is output. When the rotation of the feed screw is stopped and it is detected that the level of the raw material is lower than the specified lower limit value, the feed screw is rotationally driven, and the drive amount of the main screw and the raw material supply device is further increased. Is sampled, a calculation for setting the supply amount of the raw material is performed based on the sampled driving, and the rotation of the feed screw is set according to the result of the calculation. In that a control to the control device.

In order to achieve the above-mentioned object, an invention relating to an injection molding machine capable of automatically setting the raw material supply amount according to claim 2 is the injection molding machine according to claim 1 capable of automatically setting the raw material supply amount. , The level sensor is a reflection type level sensor provided on the side opposite to the raw material falling side so as to avoid the feed screw shaft so that the main screw is desired above the raw material supply port of the heating cylinder. It is what

In order to achieve the above-mentioned object, an invention relating to an injection molding machine capable of automatically setting the raw material supply amount of the molding machine according to claim 3 is the automatic raw material supply amount according to claim 1 or 2. In the settable injection molding machine, the level sensor is set to detect the level of the raw material behind the raw material supply port of the heating cylinder.

In order to achieve the above-mentioned object, the invention relating to the injection molding machine capable of automatically setting the raw material supply amount of the molding machine according to claim 4 is the raw material supply of the molding machine according to any one of claims 1 to 3. In the injection molding machine capable of automatically setting the amount, the level sensor is a one-contact detection type for detecting the upper limit value, and the lower limit value is a reflection type level sensor for detecting based on reset by hysteresis. It is what

In order to achieve the above object, the invention relating to the injection molding machine capable of automatically setting the raw material supply amount of the molding machine according to claim 5 is to supply the raw material for the molding machine according to any one of claims 1 to 4. In an injection molding machine capable of automatically setting the amount, the control device has a timer for measuring each driving time as an element for sampling the driving amount of the main screw and the feed screw. Is.

In order to achieve the above-mentioned object, the invention according to the method for automatically setting the raw material supply amount of the injection molding machine according to claim 6 is:
The raw material is supplied into the heating cylinder by a raw material supply device, and the main screw fitted in the heating cylinder is rotated around an axis to convey the supplied raw material to the front of the heating cylinder while plasticizing the main raw material. Injection to automatically set the amount of raw material supply to the injection mechanism that injects the plasticized raw material by stopping the rotation of the main screw by completing the measurement of the plasticized raw material by retracting to the predetermined position. A method of automatically setting the raw material supply amount of a molding machine, in which the raw material supply device is driven at a predetermined ratio to the maximum output, the level of the raw material in the raw material supply port of the heating cylinder is detected, and the raw material is placed in the heating cylinder. When it is detected that the level of the raw material is continuously higher than the preset upper limit value for a predetermined time or more, the raw material filling confirmation signal is output to stop the driving of the raw material supply device, When it is detected that the charge level is lower than the specified lower limit value, the raw material supply device is driven, and the main screw from the output of the first raw material filling confirmation signal to the completion of the predetermined number of samplings And the drive amount of the raw material supply device is sampled, and the drive amount of the sampled main screw and raw material supply device,
It is characterized in that the calculation for setting the supply amount of the raw material is performed based on the ratio of the drive to the maximum output of the raw material supply device and the setting coefficient for the filling of the raw material in the heating cylinder.

In order to achieve the above-mentioned object, the invention according to the method for automatically setting the raw material supply amount of the injection molding machine according to the seventh aspect is the method for automatically setting the raw material supply amount of the injection molding machine according to the sixth aspect. The calculation for setting the amount is performed by obtaining the ratio of the drive amounts of the sampled main screw and the raw material supply device, and the obtained ratio is the ratio of the drive to the maximum output of the raw material supply device and the raw material in the heating cylinder. It is characterized in that it is multiplied by a setting coefficient for the fullness of.

In order to achieve the above-mentioned object, the invention relating to the method for automatically setting the raw material supply amount of the injection molding machine according to claim 8 is the method for automatically setting the raw material supply amount for the injection molding machine according to claim 6 or 7. In, the element for sampling the drive amount of the main screw and the raw material supply device from the first detection that the level of the raw material continuously becomes higher than the predetermined upper limit value for a predetermined time or more until the sampling is completed, It is characterized in that it is each driving time.

In order to achieve the above-mentioned object, the invention relating to the automatic raw material supply amount setting method for an injection molding machine according to claim 9 is the method for automatically setting a raw material supply amount for an injection molding machine according to any one of claims 6 to 8. In the above, the setting coefficient for filling the raw material in the heating cylinder is a numerical value within the range of 0.85 to 0.95.

In the injection molding machine according to the present invention capable of automatically setting the raw material supply amount, when the feed screw is rotationally driven by the rotary drive means of the raw material supply device, the raw material is supplied from the feed cylinder to the heating cylinder of the injection mechanism. . As the main screw is desired above the raw material supply port, the reflection type level sensor provided on the side opposite to the raw material falling side avoiding the axis of the feed screw allows It is detected that the level has reached the set upper and lower limit levels. Therefore, the level of the raw material supplied into the heating cylinder and conveyed forward is stably and accurately detected. Then, when the control device detects that the level of the raw material in the heating cylinder is continuously higher than the upper limit value for a predetermined time or more, it outputs a raw material filling confirmation signal and stops the rotation drive of the feed screw. When it is detected that the level of the raw material has become lower than the set lower limit value based on the reset by the hysteresis of the level sensor, the feed screw is rotationally driven. The main screw is rotatably driven to convey the supplied raw material to the front of the heating cylinder while plasticizing it, and the plasticized raw material is stored in front of the heating cylinder to be retracted to a predetermined position and the measurement is completed. As a result, the rotation immobility is stopped and the rotation is advanced to perform injection.

The control device samples the driving time of the main screw and the feed screw from the first output of the raw material filling confirmation signal to the completion of the predetermined sampling times of the raw material supplied into the heating cylinder, and the sampling is performed. Calculate the ratio of the drive time, perform a calculation by multiplying this ratio by the ratio of the drive to the maximum output of the raw material supply device and the setting coefficient for the filling of the raw material in the heating cylinder, and set the raw material supply amount from this calculation result. To set and control the rotation of the feed screw.

In the method of automatically setting the amount of raw material supplied to the injection molding machine according to the present invention, in the method of automatically setting the amount of raw material supplied to the injection mechanism of the molding machine, the level of the raw material in the heating cylinder is set to a predetermined value. When it is detected that the raw material has been continuously higher than the upper limit value for more than a predetermined time, the raw material filling confirmation signal is output and the driving of the raw material feeding device is stopped, so that the moment of the raw material fed by the raw material feeding device is stopped. Therefore, the proper filling of the raw material in the heating cylinder can be accurately and stably confirmed. Then, the ratio of the driving time of the sampled main screw and the raw material supply device is obtained, and the ratio, the ratio of the drive to the maximum output of the raw material supply device, and 0.85 to 0. 9
The calculation is performed by multiplying the setting coefficient in the range of 5, and the drive of the raw material supply device is set and controlled based on the calculation result.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an injection molding machine according to the present invention will be described with reference to FIGS. The injection molding machine according to the present invention capable of automatically setting the raw material supply amount includes an injection mechanism 2, a raw material supply device 1, and a level sensor 2.
4 and a control device 26.

The injection mechanism 2 includes a heating cylinder 6 having a nozzle 5 at a front end thereof, a main screw 7 inserted in the heating cylinder 6, a rotary drive means 8 for rotationally driving the main screw 7, and a main drive. An injection drive unit 9 for ejecting the plasticized raw material from the nozzle 5 by driving the screw forward is provided. The heating barrel 6 is provided with a raw material dropping port 10 that opens upward as a raw material supply port.
In order to properly drop the raw material into the raw material dropping port 10,
A raw material supply device 1 is provided.

The heating cylinder 6 is provided with a heating temperature adjusting device such as a band heater (not shown), and is configured to plasticize by heating and melting the supplied raw material at an appropriate temperature. The rotary drive means 8 is composed of a hydraulic or electric motor and drives the main screw 7 to rotate about its axis. The number of rotations per unit time for rotating the main screw 7, that is, the rotation speed is arbitrarily set according to the molding conditions such as the type of raw material. When the main screw 7 is rotated by the drive of the rotation drive means 8, the raw material drop port 1
The raw material supplied from 0 to the heating cylinder 6 is heated and kneaded to be plasticized, and is conveyed and stored in front of the heating cylinder 6, so that the main screw 7 retracts due to its reaction.

The injection driving means 9 advances the main screw 7 retracted to a predetermined position to move the heating cylinder 6
The plasticized raw material stored in front of the nozzle is extruded and ejected from the nozzle 5. The amount of the raw material to be injected is determined by the stroke amount of the main screw 7 from the retracted position to the advanced limit position. Therefore, the injection drive means 9 is provided with detection means (not shown) such as a limit switch for detecting the retracted position of the main screw 7. When the main screw 7 retracts to the specified position, that is, when the weighing is completed, the main screw 7
The main screw 7 is driven forward by the driving of the injection driving means 9 to inject the raw material. The retracted position (measurement) of the main screw 7 and the speed at which the main screw 7 is advanced are arbitrarily set depending on the molding conditions such as the product to be molded.

As is known in the art, the raw material supply device 1 has a feed cylinder 21 and a feed screw 22 rotatably fitted in the feed cylinder 21.
And a drive means 23 for driving the number of revolutions per unit time for rotating the feed screw 22, that is, the rotational speed of the feed screw 22 to be adjustable. Between the raw material supply device 1 and the injection mechanism 2 in this embodiment, a communication passage 25 for communicating the raw material conveyed in the feed cylinder 21 to the raw material dropping port 10 of the heating cylinder 6 is provided. .

As shown in FIG. 2, the feed cylinder 21
A material dropping port 21a that opens upward is formed near the rear end (right side in the figure) of the hopper 20. A hopper 20 for storing the raw material and supplying it to the feed cylinder 21 is provided at this material dropping port 21a. Installed. Feed cylinder 2
A raw material discharge port 21b opening downward is formed near the front end (left side in the drawing) of 1, and a communication passage 25 for connecting to the raw material dropping port 10 of the heating cylinder 6 is connected. The feed screw 22 is provided with blades 22a spirally provided around the shaft 22b to feed the raw material supplied from the hopper 20 into the feed cylinder 21 to the raw material discharge port 21b by rotating around the axis. . In this embodiment, since the raw material discharge port 21b is formed near the other end of the feed cylinder 21, the feed screw 2
2 is a blade 22 at a portion substantially corresponding to the raw material discharge port 21b.
a is not provided, and the blades 22 extend from the rear end to the raw material discharge port 21b and from the raw material discharge port 21b to the front end.
a is formed in the opposite direction.

The level sensor 24 detects the level of the raw material in the raw material dropping port 10 of the heating cylinder 6, and uses ordinary light or infrared rays such as a distance setting type photoelectric switch, a distance sensor and a beam sensor. Alternatively, a reflection type using ultrasonic waves is adopted. The level sensor 24 emits the detection beam B and receives the detection beam B reflected by the raw material in the raw material dropping port 10 of the heating cylinder 6 to set the raw material in the raw material dropping port 10 of the heating cylinder 6. It is detected that the level reaches a predetermined upper limit value. The level sensor 24 may be of a two-contact detection type that detects both the upper limit value and the lower limit value. However, since this sensor is expensive and large, the upper limit value of the upper limit value is not used in this embodiment. An inexpensive and compact one-contact detection type that detects the level and detects the lower limit value based on reset by hysteresis is used. As a specific example of the reflection type level sensor in this embodiment, as a distance setting type photoelectric switch, E3S-CL manufactured by OMRON Corporation is used.
Type 2 was used, DL-S100TC type manufactured by Takenaka Electronics Co., Ltd. was used as the distance sensor, and EQ-34 type manufactured by Sunkus Co., Ltd. was used as the beam sensor.

As shown in FIG. 5, the level of the upper limit value detected by the level sensor 24 (referred to as the upper limit level UL) is, for example, 10 to 1 from the upper surface of the thread 7a of the main screw 7.
The lower limit level (referred to as lower limit level DL) is set at a position of 5 mm, and is automatically set, for example, 7 mm below the upper limit level UL that exceeds the range of the hysteresis difference of the level sensor 24, due to the characteristic characteristic of the level sensor 24. Has been done. Therefore, usually 5 to 10 mm from the upper limit level UL
If a level sensor that is reset based on hysteresis is selected at a slightly lower level, a sensor that can detect only the upper limit will suffice, so it will be inexpensive, and the operator will not have to set the lower limit. Then, the level sensor 24 outputs an ON signal when the level of the raw material in the heating cylinder 6 is at a position exceeding the upper limit level UL,
When the level of the raw material in the heating cylinder 6 is lowered below the lower limit level DL, the output ON signal is reset and the OFF signal is output.

At the position where the level sensor 24 is provided, as shown in FIG. 3, the level of the raw material in the raw material dropping port 10 of the heating cylinder 6 is controlled so that the main screw 7 is desired above the raw material dropping port 10 of the heating cylinder 6. The feed cylinder 2 avoiding the shaft 22b of the feed screw 22 so that it can be detected.
It is set above 1. Also, as shown in FIG.
Since the raw material falls into the communication passage from one side of the feed screw 22 that rotates around the axis (left side of FIG. 4, referred to as the raw material dropping side), the level sensor 24 is affected by the falling raw material as much as possible. The side opposite to the raw material falling side (Fig. 4
On the right side of). Further, in front of the raw material dropping port 10 of the heating cylinder 6, the raw material supply device 1 is used to connect the communication passage 2
As the raw material falls through 5 and the main screw 7 is pushed into the heating cylinder 6 and conveyed forward in the heating cylinder 6, the raw material level may not be stable, so as shown in FIG. The level detection point P of the sensor 24 is the heating cylinder 6
It is aligned with the rear of the raw material dropping port 10. The mounting flange 24a of the level sensor 24 is appropriately provided with a through hole or a gap (not shown) for releasing gas or the like generated from the plasticized raw material in the heating cylinder 6.

The control device 26 includes a CPU 30 and an input unit 3.
1. The output unit 32, the storage unit 33, and the setting / display unit 34 are connected by a bus line, respectively, for setting and controlling the rotation speed of the feed screw 22 that supplies the raw material to the heating cylinder 6. Is performed.

The CPU 30 calculates an appropriate number of revolutions of the feed screw 22, that is, a feed amount of the raw material, based on the data from the input unit 31 and the like, and outputs a control signal to the output unit 32 and the like. is there.

The level sensor 24 is connected to the input section 31, and the ON and OFF signals output from the level sensor 24 are input. In addition, the input unit 31
Limit switches and operation switches (not shown) of the actuator are connected. The input unit 31 is
A confirmation timer (not shown) is provided. FIG.
The relationship between the operation of the level sensor 24, the operation of the confirmation timer, and the output of the raw material filling confirmation signal is shown. (A) is the time when the ON signal input from the level sensor 24 to the input unit 31 is set. When it is shorter than Ts, (b) shows the case where the ON signal input from the level sensor 24 to the input unit 31 reaches the set time Ts.

When the ON signal input from the level sensor 24 to the input section 31 is shorter than the set time Ts of the confirmation timer (a), the raw material filling confirmation signal is not output. On the other hand, if the ON signal is continuously longer than the set time Ts of the confirmation timer (b), the raw material filling confirmation signal is output because the raw material is filled in the heating cylinder 6.

The raw material filling confirmation signal is sent to the feed screw 2
The rotation of No. 2 is stopped, and the level sensor 2 described above is used.
It is reset by the OFF signal of No. 4, and the rotational drive of the feed screw 22 is restarted by this. FIG. 7 is a flowchart showing this operation, in which the feed screw 22 is rotationally driven (S1), whereby the raw material is dropped into the raw material dropping port 10 of the heating cylinder 6, and the level sensor 2
When the raw material reaches the upper limit level UL of 4 and the ON signal is output (S2), the confirmation timer of the input unit 31 of the control device 26 starts measuring the output time of the ON signal (S3). Next, it is judged whether the output time of the ON signal timed by the confirmation timer has reached the set time Ts (S4), and ON
When the output time of the signal reaches the time Ts, the raw material filling confirmation signal is output (S5), and the feed screw 22
Is stopped (S6). On the other hand, when the output time of the ON signal has not reached the time Ts, the confirmation timer is reset (S7). Then, when the raw material in the heating cylinder 6 is lowered to the lower limit value DL exceeding the range of the hysteresis difference of the level sensor 24 by the rotational driving of the main screw 7 (S8), the level sensor 24 outputs an OFF signal and the raw material filling confirmation signal. Are reset (S9). The raw material filling confirmation signal may be the timer signal itself output from the timer for confirming the set time Ts, or may be another signal output based on the signal. In this way, when the ON operation of the level sensor 24 is shorter than the predetermined time, it is considered that a part of the raw material being dropped or the unstable raw material level is detected, and this is excluded as noise, and the predetermined level is determined. Only when the time (Ts) ON operation continues, the raw material fullness signal is output as confirmation of the raw material fullness level, and the rotation of the driving means 23 of the feed screw 22 is stopped.

The output section 32 includes a rotation driving means 8 for the main screw 7, an injection driving means 9 and a feed screw 22.
Is connected to the drive means 23 of the main screw 7, and controls the rotation drive means 8 and the injection drive means 9 of the main screw 7 at the set rotation speed, timing, stroke, etc., and
The control signal of the proper rotation number of the feed screw 22 calculated by the CPU 30 is received to receive the feed screw 2
2 drive means 23 is controlled.

The storage unit 33 stores the main screw 7 and the feed screw 2 which are sampled a predetermined number of times.
The rotational drive times Tm and Tf of the second example are stored, and the data of the rotational drive times Tm and Tf sampled as necessary are output to the CPU 30 and the setting / display unit 34.

The setting / display unit 34 comprises an input means such as a keyboard and a display means such as a CRT, and is provided with an automatic setting switch for automatically setting the supply amount of raw material (not shown). ). The input means sets and inputs the rotation speed of the rotation drive means 8 of the main screw 7, the timing and stroke of the injection drive means 9, and the like. Further, the display means displays the number of times of sampling, the sampled data and the like, in addition to the number of rotations of the rotation driving means 8 of the main screw 7 and the timing and stroke of the injection driving means 9 which have been set and input.

Next, the method for automatically setting the raw material supply amount according to the present invention will be described with reference to FIG. 8 using the injection molding machine configured as described above and capable of automatically setting the raw material supply amount.

The method for automatically setting the amount of raw material supply according to the present invention roughly includes rotating the main screw 7 at a predetermined number of revolutions and rotating the feed screw 22 at a set number of revolutions so that the main screw 7 and the feed screw 22 are rotated. Of the feed screw 22 and the ratio of the set number of revolutions to the maximum output of the drive of the feed screw 22 are multiplied by this ratio and the ratio of the set number of revolutions of the feed screw 22 to the rotation of the feed screw 22 is calculated. The number set value is calculated.
The method for automatically setting the supply amount of the raw material according to the present invention can be performed not only before the start of the molding operation but also when the supply amount of the raw material is not suitable during the molding.

The method for automatically setting the amount of raw material supply according to the present invention will be described in detail below. When performing the automatic setting, first, the automatic setting switch of the setting / display unit 34 of the control device 26 is turned on (S11), and then the rotational speed n = X% of the feed screw 22 is set and input ( S12). The rotation speed n of the feed screw 22 to be set is set to the maximum rotation speed capability (maximum output) of the feed screw 22, that is, 100% in order to shorten the time required for sampling and reduce the amount of raw material used for sampling. However, if the raw material is supplied to the raw material dropping port 10 of the heating cylinder 6 in a short time, the degassing of the gas generated from the plasticized raw material in the heating cylinder 6 is affected. It is set to an arbitrary value (X%) so that it will not be adversely affected.

The feed screw 22 is rotationally driven at a rotational speed n = X% to supply the raw material to the heating cylinder 6, and the main screw 7 is rotationally driven to heat the raw material supplied into the heating cylinder 6 while plasticizing the raw material. When the raw material filling confirmation signal is first output after the main screw 7 is conveyed backward to the cylinder 6 and the main screw 7 retracts and starts weighing, sampling of the drive time of each of the main screw 7 and the feed screw 22 is performed. Start, integrate each driving time, Tm, Tf
Is calculated (S13). This sampling is repeated a predetermined number of times.

Next, the raw material supplied into the heating cylinder 6 is plasticized by the rotational driving of the main screw 7, and it is judged whether the main screw 7 is retracted to a predetermined position to complete the measurement (S14). . When the weighing is not completed in S14, it is determined whether the raw material filling confirmation signal is output (S15). When the raw material filling confirmation signal is not output, the rotation of the feed screw 22 is started and , Tf sampling is started (S1
6). When the raw material filling confirmation signal is output, the rotation driving of the feed screw 22 is stopped and the sampling of the driving time Tf is interrupted (S1).
7). For the output of the raw material filling confirmation signal and its reset, the means already described in detail with reference to FIG. 7 is applied. On the other hand, when the measurement is completed in S14, it is determined whether the number of times of sampling has reached a predetermined value (S18), and next, the total value of the driving times Tm and Tf sampled a predetermined number of times is calculated, and The rotation speed set value of the feed screw 22 is calculated as nf by multiplying the total ratio of the driving times Tm and Tf by the setting coefficient Y and the set rotation speed n of the feed screw 22 (S1).
9).

The setting coefficient Y is set in the heating cylinder 6 which gives the optimum result when the raw material is filled with the heating cylinder 6, that is, 100% when the raw material is actually plasticized. It is the ratio of the amount of raw materials supplied, and is empirically 85-95.
%, Preferably about 90%.

The calculated rotation speed nf is set as the rotation speed setting value of the feed screw (S20), and the automatic setting switch is turned off.
It becomes FF and ends the automatic setting (S21). In addition, here, the rotation speed n of the feed screw in S12,
The rotational speed nf of the feed screw in S19 and S20 is shown as a ratio (%) to the rotational speed of 100%, but it goes without saying that the rotational speed itself may be indicated by the value of the rotational speed itself.

[0049]

According to the present invention, the driving time of the main screw and the raw material supply device from the output of the first raw material filling confirmation signal to the completion of the measurement is sampled, and the sampled main screw and the raw material supply device are sampled. The main screw and the feed screw are calculated in order to calculate the ratio of the driving times, and to multiply the calculated ratio by the ratio of driving to the maximum output of the raw material supply device and the setting coefficient for the filling of the raw material in the heating cylinder. For each of the above, it is not necessary to set and input the raw material supply amount per one revolution as a coefficient for each raw material to be used, and the content of calculation can be simplified.

Further, according to the present invention, a reflection type level sensor is provided above the raw material supply port of the heating cylinder on the side opposite to the raw material dropping side so as to avoid the feed screw shaft so that the main screw is desired. To detect the level of the raw material in the raw material supply port of the heating cylinder, and to check that the raw material level in the heating cylinder is continuously higher than the set upper limit value for a predetermined time or more. If detected, the raw material filling confirmation signal is output and the drive of the raw material supply device is stopped, so the raw material level is detected stably without being affected by the temporary change in the raw material level supplied to the heating cylinder. can do. Further, when it is detected that the level of the raw material is lower than the set lower limit value, the raw material supply device is driven, so that the supply of the raw material is not insufficient, and an appropriate amount of the raw material is placed in the heating cylinder. Can be supplied.

Further, in the present invention, when the level sensor is provided so as to detect the level of the raw material behind the raw material supply port of the heating cylinder, the level of the raw material can be detected more stably. Further, in the case of using the one-contact detection type level sensor that detects the upper limit value and the lower limit value based on the reset due to the hysteresis, it can be made inexpensive and compact, and injection molding is performed. It is possible to reduce the troublesomeness of the operator's setting in half.

From the above, according to the present invention, it is possible to properly set the raw material supply amount of the injection molding machine regardless of the type of raw material by using a relatively simple and inexpensive device.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a main part showing an embodiment of an injection molding machine capable of automatically setting a raw material supply amount according to the present invention.

FIG. 2 is a partially enlarged view including a raw material supply device in FIG.

FIG. 3 is a plan view showing a mounting position of a level sensor with respect to a feed screw.

FIG. 4 is a sectional side view of FIG. 3;

FIG. 5 is a diagram showing an upper limit level and a lower limit level for outputting ON and OFF signals of a level sensor.

FIG. 6 shows the operation of the level sensor and the operation of the confirmation timer,
It is explanatory drawing which showed the relationship with the output of the raw material filling confirmation signal.

FIG. 7 is a flowchart showing control of a feed screw by a level sensor.

FIG. 8 is a flowchart showing a raw material supply amount setting method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 raw material supply device 2 injection mechanism 6 heating cylinder 7 main screw 8 rotation drive means 9 injection drive means 10 raw material dropping port (raw material supply port) 21 feed cylinder 22 feed screw 23 drive means 24 level sensor 26 control device B detection beam

Claims (9)

[Claims] 1. An injection mechanism comprising a main screw fitted in a heating cylinder, a rotation drive means for rotationally driving the main screw around an axis, and an injection drive means for axially driving the main screw. A feed cylinder, a feed screw fitted into the feed cylinder, and a rotation drive means for rotationally driving the feed screw so that the speed of the feed screw can be adjusted, and a raw material supply device for supplying a raw material to the injection mechanism, A level sensor that detects when the raw material in the raw material supply port of the heating cylinder has reached the set upper and lower limit levels, and the level of the raw material in the heating cylinder is continuously higher than the upper limit for a predetermined time or more. When it is detected that the temperature has become high, a raw material filling confirmation signal is output to stop the rotation of the feed screw, and the raw material level becomes lower than the specified lower limit value. When it is detected, the feed screw is driven to rotate, the driving amounts of the main screw and the raw material feeding device are sampled, and the calculation for setting the raw material feeding amount is performed based on the sampled driving. An injection molding machine capable of automatically setting a raw material supply amount, which is provided with a control device for setting and controlling rotation of a feed screw according to a result of the calculation. 2. The level sensor is a reflection type level sensor which is provided on the side opposite to the raw material falling side while avoiding the axis of the feed screw so that the main screw is desired above the raw material supply port of the heating cylinder. The injection molding machine according to claim 1, wherein the raw material supply amount can be automatically set. 3. The automatic setting of the raw material supply amount according to claim 1 or 2, wherein the level sensor is set to detect the level of the raw material behind the raw material supply port of the heating cylinder. Injection molding machine capable of. 4. The level sensor is a one-contact detection type for detecting an upper limit value, and is a reflection type level sensor for detecting a lower limit value based on resetting due to hysteresis. An injection molding machine capable of automatically setting the raw material supply amount according to any one of 1. 5. The controller according to claim 1, further comprising a timer for measuring the driving time of each of the main screw and the feed screw as an element for sampling the driving amount of the main screw and the feed screw. An injection molding machine capable of automatically setting the raw material supply amount described in. 6. A raw material is supplied into the heating cylinder by a raw material supply device, and a main screw fitted in the heating cylinder is rotated around an axis to plasticize the supplied raw material to the front of the heating cylinder. The main screw is conveyed and retracted to a predetermined position to complete the measurement of the plasticized raw material, the rotation of the main screw is stopped, and the raw material supply amount to the injection mechanism for injecting the plasticized raw material is automatically adjusted. A method for automatically setting the raw material supply amount of the injection molding machine for setting, which drives the raw material supply device at a predetermined ratio to the maximum output, detects the level of the raw material in the raw material supply port of the heating cylinder, and heats it. When it is detected that the cylinder is filled with the raw material and the level of the raw material is continuously higher than the preset upper limit value for a predetermined time or more, the raw material filling confirmation signal is output and the raw material supply device Operation is stopped, and when it is detected that the raw material level is lower than the set lower limit value, the raw material supply device is driven, and the predetermined sampling frequency is completed from the output of the first raw material filling confirmation signal. The drive amounts of the main screw and the raw material supply device until the sampling are sampled, the drive amount of the sampled main screw and the raw material supply device, the ratio of the drive to the maximum output of the raw material supply device, and the raw material in the heating cylinder. A raw material supply amount automatic setting method for an injection molding machine, comprising: performing a calculation for setting a raw material supply amount based on a setting coefficient for filling. 7. The calculation for setting the supply amount of the raw material is
Obtaining the ratio between the sampled main screw and the drive amount of the raw material supply device, and multiplying the obtained ratio by the ratio of drive to the maximum output of the raw material supply device and the setting coefficient for filling the raw material in the heating cylinder. The raw material supply amount automatic setting method for an injection molding machine according to claim 6, wherein. 8. A drive amount of a main screw and a raw material supply device is sampled after the first detection that the raw material level continuously rises above a predetermined upper limit value for a predetermined time or more until the sampling is completed. The element is a drive time for each of the elements, characterized in that
5. The method for automatically setting the raw material supply amount of an injection molding machine according to any one of 1. 9. The injection molding machine according to claim 6, wherein the setting coefficient for the filling of the raw material in the heating cylinder is a numerical value within the range of 0.85 to 0.95. Automatic setting method of raw material supply.