JPS5931127A - Plastics transfer molding apparatus - Google Patents

Abstract

PURPOSE:To effect a stable molding by controlling the negative pressure exerted on the tip part of a plunger simultaneously with the molding time, plunger speed and pressure force. CONSTITUTION:The revolution speed of a motor 21 used as a driving source for a plunger 17 is controlled to be a fixed speed by a controller 26 such as a microcomputer or the like. At the same time, the traveling distance of the plunger 17 as well as the negative pressure exerted to the tip part 17c of the plunger are detected by a measurement 19 and a pressure gauge 20 respectively. When the negative pressure is increased, the traveling speed of the plunger obtained by the measurement 19 and the negative pressure detected by the pressure gauge 20 are converted to an electric signal which is fed back to the revolution speed of the motor 21 by the controller 26 to increase the torque so that the plunger 17 can perform a uniform motion. The molding condition is stabilized and a stable product is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer molding apparatus for molding plastics.

A conventional transfer molding apparatus of this type is explained with reference to FIG.
7 is a plunger, 1a is a plunger tip, 8 is a moving piece, 9 is an upper limit switch, 10 is a play limit switch, 11 is a pot, 12 is a resin (tablet),
13 is an upper heat plate, 14 is an upper mold, 15 is a lower mold, and 16 is a lower heat plate. In this configuration, the upper mold 14 and the lower mold 15 are the upper heat plate 13 and the lower heat plate 16. The lower mold 15 is heated to a predetermined temperature, and the lower mold 15 is raised together with the lower heat plate 16 by means not shown, and the upper mold 14 is heated to a predetermined temperature.
It is designed to be joined and clamped.

The operation of this configuration is such that after the upper mold 14 and the lower mold 15 are clamped together, the resin 12 preheated to a predetermined temperature and rolled is put into the pot 11, and then the resin 12 is immediately placed in the hydraulic cylinder 3. Then, hydraulic oil is fed from the hydraulic supply and discharge pipe 4, and the piston 6 descends at high speed. A plunger 7 is connected to this piston 6, and the plunger 7 descends at high speed together with the piston 6, and the plunger tip 7a pressurizes the resin 12 at the bottom of the pot 11. The material is filled into the upper mold 14 and lower mold 15 through holes formed in the mold 14, and molded. When the movable piece 8, which is provided to move together with the plunger 7 that has descended at high speed, reaches a position where it comes into contact with the brake limit switch 10, the plunger 7 descends at low speed and high pressure and eventually stops. At this point, the resin 12 is injected and the resin pressure is obtained.Next, after a predetermined period of time has elapsed, hydraulic oil is fed into the hydraulic cylinder 3 from the hydraulic pressure supply/discharge pipe 5, and this causes the plunger to move together with the piston 6. 1 moves up at high speed and when the moving piece 8 comes into contact with the upper limit switch 9, the piston 6 and plunger 1 stop.

At this point, the lower mold 15 is replaced by the lower heat plate 16.
The molding is completed when 4ff is removed from the upper mold 14.

The above is a brief explanation of conventional plastic transfer molding equipment. In this equipment, the pressure and speed to pressurize the resin are given by the oil pressure of the hydraulic cylinder, so after the resin is put into the pot, the resin softens. ,
When the plunger tip receives load pressure from the resin (arrow A in Figure 1) during the flow and hardening process,
This method has problems in that it is not possible to adjust the pressure, and therefore the molding conditions vary and stable molding cannot be performed. In other words, the fluctuations in the load pressure from the resin mentioned above are caused by variations in the properties (particle size, pressure ratio, preheating temperature) of the molding resin from lot to lot, and the temperatures of the upper and lower molds, etc. In transfer molding equipment, when this load pressure becomes abnormally large, the molding pressure suddenly weakens, and in some cases, the plunger stops, making it impossible to obtain stable molding conditions, which has a large effect on the molded product. .

The purpose of the present invention is to solve these drawbacks. In order to achieve this purpose, a motor is used as a drive source for the plunger, and the rotational speed of the motor is kept at a constant speed by a control unit such as a microcomputer. At the same time, the moving distance of the plunger is detected by a length measuring device, and the load pressure applied to the tip of the plunger is detected by a pressure gauge, and when the load pressure increases, the plunger moving speed and the value obtained by the length measuring device are detected. The load pressure detected by the pressure gauge is converted into an electrical signal, which is fed back to the rotational speed of the motor by the control unit, and the torque is increased to control the plunger so that it can move at a constant velocity. Features.

The following will be explained with reference to the drawings. First, Fig. 2 is a block diagram showing the entire system for explaining the present invention in detail. In the figure, the signal A is the load pressure, and the load pressure at a certain plunger position is expressed as Al and A2. do. Also, LL+”
2 is the appropriate length of the plunger, LP is the low pressure load pressure limit, and HP is the high pressure load pressure limit. In the present invention, a motor is used as a driving source for the plunger, and when the motor rotates in the forward direction, the plunger descends, and when the motor rotates in the reverse direction, the plunger rises.

To explain the principle of the present invention step by step, (1) After heating the upper and lower molds to a predetermined temperature, when preheated resin is put into the pot, the 5TART shown in FIG.
It takes.

(2) At the same time as 5TART, the motor rotates forward and the plunger descends at high speed. This lowering continues until the plunger reaches the plunger position sensor. In other words, the motor is rotated until the plunger position sensor turns ON (feedback is provided from the plunger position sensor to normal rotation of the motor).

(3) When the plunger reaches the plunger position sensor, that is, when the plunger position sensor is turned ON, the motor speed is changed and low-speed descent starts at the preset plunger movement speed (42 Next, when the plunger descends at a low speed, the scale of the pressure gauge is Lp (A
□ (If HP is displayed, it means that the load pressure applied to the plunger tip is appropriate, so the motor speed will be changed again based on the detected values of the load pressure and plunger movement speed.) Under the control of the control unit, the pumping is carried out at a constant speed and then lowered at a low speed.Then, when the scale of the pressure gauge is displayed as LP (A2 (HP), the above cycle is repeated again until the filling of the resin is completed. Continue.

When filling with resin is completed, the lower limit of the plunger position is detected, the motor rotates in reverse and the plunger rises, and when it reaches the upper limit sensor, the motor stops and the plunger stops rising. The mold descends and molding is completed, marking END. Note that the moving speed of the plunger is obtained by dividing the plunger position detection by time.

(5) On the other hand, if LP ) Al or A1>HP occurs when the plunger descends at low speed due to variations in resin (tablet) lots or other changes in conditions, the load pressure exceeds the specified range. There is.

(6) Here, in the case of LP)AI, the load pressure applied to the tip of the plunger is in a low pressure state, and in this case, it passes through (B) and reaches the block of the length measuring device. When the plunger length measured by this length measuring device is ≧L1, that is, the plunger length is appropriate or long (a long plunger length means that the plunger position is too far down from the specified position) ) is a case where the load pressure applied to the plunger tip is extremely low. In this case, from ≧L1, change the motor speed and repeat the pressure gauge measurement through (C). This length measuring device is equipped with a timer, and if the predetermined resin filling time is O'VERt, then -
Stop the rotation of the evening, stop the descent of the Tefranja, and then (D
), the motor is reversely rotated to raise the plunger, and when the upper limit sensor is turned on, the motor stops and the plunger stops. Also, if the resin filling time is within the predetermined time, the motor speed is changed again through (E) and the pressure measurement using the pressure gauge is repeated (7) On the other hand, A1<
In the case of Hp, the load pressure is high against the tip of the granger.
If the pressure is appropriate, the motor is rotated in the forward direction, the motor speed is changed again through (G), and the load pressure measurement with the pressure gauge is repeated. If the load pressure is measured again and the pressure is still high, the pressure gauge is equipped with a timer, so when the resin filling time reaches 0VER, the motor rotation is temporarily stopped, is rotated in the opposite direction to finish molding.Also, if the load pressure is high and the resin filling time is within the specified range, pass (through) and measure the pressure again with the pressure gauge.During the above operation, (i1 The meaning of measuring the load pressure after stopping the motor through 1) is that even if the plunger has stopped descending, it is determined that load pressure is being applied to the tip of the plunger due to fluctuations in the resin.

(8) As mentioned above, if the load pressure on the plunger tip is appropriate (LP<Al<HP), the low pressure (LP)
Check the slow descent of the plunger for each case: Al) and high pressure (A1>HP).

In the case of low pressure or high pressure, the time, speed and pressure are controlled by a timer, motor, pressure gauge and length measuring device, and stable molding conditions are obtained by this method.

Next, an embodiment of the plastic transfer molding apparatus of the present invention based on the above-mentioned concept will be described with reference to FIG. In the figure, 1 is a bed, and 2 is a support stand installed on the bed 1. A pot 11 into which resin 12 is put is fitted into the support liner 2, and an upper part is placed on the lower side of the support stand 2. The heat plate 13 and the upper mold 14 are fixed together. 15 is a lower mold corresponding to the upper mold 14;
16 is a lower heat plate, and this lower mold 15 is a lower heat plate.
It rises together with the W heat plate 16, and is connected to the upper mold 14 to be clamped. Note that these components are the same as those in Figure 1, so the same symbols are used. .

17 is a plunger that is movable up and down on the upper surface of the support base 2, 11a is the tip of the plunger, and a movable plate 18 is fixed at an appropriate position in the middle of this plunger 17,
A length measuring device 19 for detecting the moving position of the plunger 11 is installed at a predetermined position on the moving plate 18, and a pressure gauge 2° for detecting the load pressure is provided at the rear end, that is, the upper end of the plunger 1T. .

21 is a motor, and this motor 21 is fixed to a column 22 provided on the bed 1, and a gear 23 is attached to its rotating shaft.024 is rotatably supported on the column 22 via a support plate or the like. The feed screw has a gear 25 at its upper end, and the gear 25 meshes with the gear 23. The feed screw 24 is screwed into a screw hole provided in a movable plate 18 that is integrated with the plunger 17, and is connected to the motor 2.
1 is correct.

When the feed screw 24 rotates in the reverse direction, the plunger 1T descends and rises in accordance with the rotation.

26 is a control unit such as a microcomputer, which controls the plunger 1T in accordance with the plunger movement speed obtained by the length measuring device 19 and the load pressure detected by the pressure gauge 20.
It functions to control the rotation of the motor 21 so that the moving speed of the motor 21 is controlled to a set value.

Next, to explain the operation of the above-mentioned configuration, first, the upper mold 14 and the lower mold 15 are heated to predetermined temperatures by the upper heat plate 13 and the lower heat plate 16, and then the lower mold 15 is heated together with the lower heat plate 16. is raised, thereby joining and clamping the lower mold 15 to the upper mold 14. After this clamping is completed, the resin 12 preheated to a predetermined temperature is put into the pot 11, and the plunger 11 is lowered immediately after the resin 12 is put into the pot 11. This lowering of the plunger 17 is performed by rotating the motor 21 in the forward direction. That is, when the motor 21 rotates, its rotational force is transmitted to the feed screw 24 via the gear 23.25.
As the feed screw 24 rotates, the movable plate 18 screwed with the feed screw 24 is pushed downward, so that the plunger 11 descends together with the movable plate 18.

When the plunger 17 descends, the plunger tip 17a pressurizes the resin 12 in the pot 11, and the pressurized resin 12 passes through the hole provided in the upper mold 14 and connects the upper mold 14 and the lower part. It is filled into the mold 15, but at this time, the 4F11 fat 12 softens.

During the flow and hardening process, load pressure (arrow A) may be applied to the plunger tip 17a due to variations in properties of the resin 12 depending on the lot. This load pressure is the plunger 1
7 is detected by the pressure gauge 20 provided at the upper end of the
Also, at Kaimei, the length measuring device 1 placed on the moving plate 18
9 also detects the moving distance of the plunger 11. Then, the detected load pressure and moving distance are converted into electrical signals, which are input to the control unit 26 to be output as a voltage, and the rotational speed of the motor 21 is controlled by this voltage. As a result, the time from the start to the end of molding of the resin 12, the descending speed of the plunger 1T, and the pressure applied to the resin 12 can be controlled simultaneously, so even if the load pressure increases, the torque of the motor 21 increases, and the plunger 11 is maintained at a constant velocity of descent. When a predetermined molding time has elapsed, the motor 21 reverses, the plunger 1T rises, and the mold 15 immediately below it descends together with the lower heat plate 16. It is separated from the upper mold 14 and molding is completed.

As explained above, the present invention provides a method for softening, flowing, and hardening the resin after pouring 1 gold and 1 degree fat into the pot.
The load pressure applied to the tip of the plunger is controlled simultaneously by controlling the molding time, plunger speed, and pressurizing force, so that uniform velocity movement of the plunger is obtained, so constant molding conditions are always obtained. This has the effect that stable molding can be performed. Therefore, it can be applied to all types of plastic molding, regardless of whether the molded product is large or small, and regardless of the size and shape of the molded product.It can also be applied to all kinds of plastic molding, regardless of whether the resin used is thermosetting or thermoplastic. Molds can be used for all types of molds, regardless of the number of cavities, structural dimensions, and materials.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a conventional plastic transfer molding device, Fig. 2 is a block diagram of the entire system showing the principle of the present invention, and Fig. 3 is a front view showing a plastic transfer molding device according to the present invention. be. 1... Bed 2... Support stand 11... Pot 1
2... Resin 13... Upper heat plate 14.
... Upper mold 15 ... Lower mold 16 ... Lower heat plate 17 ... Plunger 17a ... Plunger tip 18 ... Moving plate 19 ... Length measuring device 2
0... Pressure gauge 21... Motor 22... Support 23... Gear 24... Feed 9 screw 25... Gear 26... Suppression part patent Applicant Oki Electric Industry Co., Ltd. Agent: Patent Attorney Takashi Kanakura Procedural Amendment (spontaneous) May 19, 1981 Kazuo Wakasugi, Commissioner of the Patent Office 1, Case Description 1982 Patent Application No. 141878 2, Title of Invention: Plastic Transfer Molding Device 3, connection with the case of the person making the amendment Patent applicant address 1-7-12 Toranomon, Minato-ku, Tokyo Name (029) Oki Electric Industry Co., Ltd. 7 “Hashimoto”
Nankai Otoko 4, Agent 1, corrected "1 is bed" on page 2, line 9 of the specification and page 10, line 10 to read "1 is bed." 2. Amend "through the hole" to "through the sprue" on page 3, line 12 of the specification, and page 13, line 5. 3. Change "Bed 1" on page 11, line 9 of the specification to "Bed 1".
” he corrected. 4. Change "1... bet" on page 15, line 7 of the specification to "1.
...Bed,” he corrected.

Claims (1)

[Claims] 1. An upper mold, a lower mold that is joined and clamped to the upper mold, an upper heat plate and a lower heat plate that heat each mold, and a bot provided on the upper mold. , a vertically movable plunger that pressurizes the resin put into the pot and fills the resin into the upper and lower molds, a motor that raises and lowers the plunger, and a motor that is applied to the tip of the plunger. a pressure gauge for detecting the load pressure; a length measuring device for detecting the moving distance when the plunger is lowered; In addition to controlling the rotation speed, when the pressure exceeds the specified value, the rotation of the motor is temporarily stopped, and the motor is rotated again according to the plunger position and pressure, and after a predetermined period of time, the pressure still exceeds the specified value. A plastic transfer molding device comprising: a control unit that rotates a motor to raise a plunger when the plunger is raised.