JPH01262100A - Control method for compacting machine - Google Patents

Abstract

PURPOSE:To perform the control of a compacting machine so as to obtain a good part by controlling the speed reduction control prior to switching to the pressure control from the speed control of the die of one part by the moving speed of a hydraulic cylinder to smoothly transfer to a pressure control, in the case of compacting a resin work inside the cavity of between a pair of dies. CONSTITUTION:One part of the die of a pair of dies 11, 12 is moved by a hydraulic cylinder 4 or 7 and a resin work is compacted inside the cavity 13 of between both dies 11, 12. In this case, the moving speed of the hydraulic cylinder 4 or 7 is controlled until the pressurizing of the work starts and the pressurizing force of the cylinder 4 or 7 is controlled after the pressurizing starts. The speed reduction control in the speed control prior to switching to the pressure control from the same speed is controlled by the speed V shown by an equation at the moving speed of the cylinder 4 or 7. The transfer to the pressure control is thus made possible smoothly, the pressure corresponding to a resin can be given and a good part can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a compression molding machine for compression molding synthetic resin materials.

[Conventional technology]

A conventional compression molding machine includes a heath, an applied installed vertically on the heath, a crown provided above the apply 1, a hydraulic cylinder provided on the crown, and supported at the lower end of the rond of the hydraulic cylinder. A lower mold is fixed to the upper surface of the hese, an upper mold is fixed to the lower surface of the slide, and the resin is compressed in the cavity between the upper and lower molds. It was meant to be molded.

In the conventional compression molding machine, SMC material (Shee
To compression mold the molding compound (thermosetting sort material), a hydraulic cylinder was used as shown in FIG. That is, the period from when the slide descends from the top dead center until the mold is clamped (t+, t2.
tz) adopts speed control that controls the speed of the hydraulic cylinder in multiple stages, and after the monthly charge fills the mold cavity until compression molding is completed (ta, ts),
Pressure control was adopted to keep the pressurizing force of the hydraulic cylinder constant, and the speed control was switched again from completion of molding to mold opening (1, 3, L7).

As shown in Figure 11, the pressure behavior of the SMC material inside the mold is such that the pressure rises rapidly the moment the mold touches the resin, causing it to flow and fill. The heated SMC4A moon expands as shown by "a" in the figure, and its pressure increases. Then "b"
With the correct amount of ``c'', G-saitri 1(?i) occurs and the pressure decreases.After that, curing progresses with the correct amount of ``c''.

In other words, for materials that expand, contract, and harden after being filled with resin, optimal pressure control must be performed for each state, and if pressure control is inappropriate, hairs and cracks may occur. It is shown that.

Therefore, when compression molding a thermosetting resin material, it is extremely important to appropriately transition from the speed control to pressure control and to maintain an appropriate pressure during pressure control.

[Problem to be solved by the invention]

However, conventionally, the transition from speed control to pressure control has been performed by switching the speed of the slide in multiple stages, as shown in FIG.

Therefore, at the speed switching point, the speed becomes discontinuous,
Smooth casting speed may not be obtained, and the mold may touch the resin suddenly or slowly, or may touch the resin without vibrating, resulting in improper filling of the resin (material fill). This was not done and had a negative impact on subsequent pressure control.

Also, depending on the type of resin, it is necessary to lower the slide at high speed and then decelerate rapidly and smoothly in the final stage, but the conventional multi-step deceleration pattern is impossible, so it is difficult to mold the slide optimally for each resin. The problem was that it couldn't be done.

On the other hand, in the pressure control ff1l, as shown in Part 10, pressure was conventionally applied at a substantially constant pressure, so it was difficult to obtain a good quality molded product for resins that undergo expansion, contraction, and curing. There was a problem.

Therefore, the present invention makes it possible to smoothly shift to pressure control in speed control, and in pressure control, to apply pressure according to the state of the resin, so that good products can be obtained. The purpose of the present invention is to provide a method for controlling a compression molding machine.

[Means to solve the problem]

A method for controlling a compressor according to the present invention to achieve the above object is to move one of a pair of molds using a hydraulic cylinder, and compression mold a resin processed product in a cavity between the molds. In the compression molding machine control method, the moving speed of the hydraulic cylinder is controlled until the start of pressurization of the workpiece, and the pressurizing force of the hydraulic cylinder is controlled after the j3a pressure starts, in which the speed control is switched to pressure control. The deceleration control following the previous speed control changes the moving speed V of the hydraulic cylinder to v-(Z+Zz) 'e-! ” α Zl: Hydraulic cylinder stroke position Z2 at the start of deceleration control; Hydraulic cylinder stroke position it when switching from speed control i+11 to pressure control α: Time constant e: Base t of natural logarithm, deceleration control The feature is that the pressure control is controlled based on the time from the start.Furthermore, the pressure control is performed at a constant pressure P for a certain time T after the start of the pressure control.

and the subsequent pressure P is 1) =I], -1-(+). -p+)・-haP1;
Pressure β of the hydraulic cylinder at the end of compression molding; time constant e; base t of natural logarithm; constant time T. It is characterized by the fact that it is controlled by the time since Pi.

[For production]

Claim] iid+li! According to the present invention, since the speed control of the hydraulic cylinder is performed using an exponential function,
The deceleration becomes smoother and uniform material flow can be obtained. Furthermore, by changing the deceleration position and time constant, an optimal deceleration pattern corresponding to each resin can be obtained. As a result, subsequent pressure control can be maintained at optimal molding conditions.

According to the second aspect of the present invention, the pressurizing force is exponentially controlled, and this exponential control closely matches the actual pressure behavior within the mold. That is, since the pressure is controlled to correspond to the expansion-contraction-hardening reaction that occurs during resin molding, molding can be performed under optimal pressure conditions depending on each resin.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

The one shown in Fig. 6 is a compression molding machine for SMC, which includes a head 1 fixed to the floor, amp lights 2 erected at the four corners of the bed 1, and the upper end of the upride 2 of the four trees. It has a crown 3 that connects and fixes the parts. A single-acting main cylinder 4 is attached to the center of the crown 3. A piston rod 5 of the main cylinder 4 protrudes below the crown 3, and a slide 6 is connected to the lower end of the piston rod 5. This slide 6 is guided by the four Ameplites 2 and is movable up and down. Also, double-acting sub-cylinders 7 are provided on both the left and right sides of the crown 3.
A piston rod 8 of this sub-cylinder 7 is connected to the slide 6.

Leveling cylinders 9 are provided at the four corners of the heel 1" 1, and the screws 1 and 10 of this cylinder 9 are
The F end surface abuts on the lower surface of the slide 6 so as to be able to move toward and away from it.

An upper mold 11 is detachably attached to the lower surface of the slide 6, and a lower mold 12 is detachably attached to the -L surface of the bed 1.

The upper and lower molds 1L12 are configured such that a cavity 13 is formed at the mating portion of the two when the molds are clamped, and a mold pressure sensor for detecting the pressure inside the cavity 13 is installed in the lower mold 12. is built-in.

A rotary encoder 15 is attached to the side of the hend 1 L.
-1, and a sprocket 16 attached to the input shaft of the encoder 15, and a sprocket 17 rotatably attached to the side surface of the crown 3.
is wound around it, and both ends of this chino 18 are locked to a bracket 9 attached to the slide 6. Thus, the encoder 15 detects the position and moving speed of the slide 6.

An oil tank 20 is mounted on the crown 3, and the oil tank 20 and the main cylinder 4 are connected via a full oil valve 21. Further, the main cylinder 4 and the sub cylinder 7 are connected to a pressurizing cylinder hydraulic unit 25 via hydraulic pipes 22, 23, and 24. Further, the leveling cylinder 9 is connected to a leveling hydraulic unit 27 via a hydraulic pipe 26.

The pressure cylinder hydraulic unit 25, the leveling hydraulic unit 27, the mold pressure sensor 14, and the rotary encoder 15 are electrically connected to a control means 28.

In addition, 29 is a mold general entry/exit stand.

What is shown in FIG. 7 is a hydraulic circuit diagram inside the hydraulic unit 25 for the pressurizing cylinder.

In the figure, 30 is an oil tank, and M, L are first and second mokes for driving the hydraulic pump.

The first motor drives two speed control first and second servo pumps PiP2, and the second motor M2 drives third and fourth hydraulic pumps P:1. P4 and servo hydraulic pump P,
and is driving.

The discharge ports of the first to fourth pumps (P1 to P4) are the first to fourth pumps (P1 to P4).
They are connected to hydraulic lines 3L32, 33, and 3.1, respectively. The first to fourth hydraulic lines 3L32, 33.34 are collected into a fifth hydraulic line 35, and the fifth hydraulic line 35 branches into sixth and seventh hydraulic lines 36,37. The sixth hydraulic line 36 branches into the hydraulic pipe 22 connected to the main cylinder 4 and the hydraulic pipe 23 connected to the head side of the sub cylinder 7. The seventh hydraulic line 37 is connected to the hydraulic piping 24 connected to the rond side of the sub cylinder 7.

The pilot hydraulic piping 38 connected to the discharge port of the Nervo hydraulic pump P is indicated by a dotted line in the figure.

Remote control relief valves 39.40, 41.42 are interposed in the first to fourth hydraulic lines 3], 32, 33, and 34, respectively, and each relief valve 39, 4o, 4t:42 is connected to a thin line 43. It is connected to the. A cooler 44 is interposed in the train line 43.

The sixth hydraulic line 36 includes first to third on/off valves 11.
5.46.47 is interposed. 1st on/off valve 4
5 allows the sixth hydraulic line 36 to be opened and closed. The second on/off valve 46 connects the sixth hydraulic line 36 to the oil tank 30.
open to The third on/off valve 47 allows the main cylinder piping 22 to be opened and closed. Each of these on/off valves 45
．． 46 and 47 are operated by the hydraulic pressure of the pilot hydraulic pipe 38. This operation is performed by a command from the control means 28.

A sixth valve between the first on-off valve 45 and the third on-off valve 47
A pressure control valve 48 is interposed in the hydraulic line 36 . The pressure control valve 48 is capable of changing its set pressure steplessly or stepwise according to a command from the control means 28.

The seventh hydraulic line 37 also has fourth to sixth on/off valves 49.
50.51 are interposed. Each of these on/off valves 4
9.50.51 is also opened and closed by commands from the control means 28.

A check valve 52 is built into the full oil valve 21, and the check valve 52 is turned ON/OFF by the hydraulic pressure of the pilot hydraulic piping 38. This operation is also performed by the control means 28.
This is done under the direction of

FIG. 8 is a hydraulic circuit diagram of the rehering hydraulic unit 27, and the hydraulic oil in the oil tank 53 is supplied to the hydraulic pump P+1.
, and is connected to the hydraulic pipe 26 which is connected to the rehering cylinder 9 through an eighth hydraulic line 54. A servo valve 55 is interposed in this eighth hydraulic line 54, and the servo valve 55 is operated by a command from the control means 28. Four servo valves 55 are provided corresponding to each leveling cylinder 9.

What is shown in FIG. 9 is an operational flow diagram of the compression molding machine having the above configuration, and what is shown in FIG. 1 is an operational diagram thereof.

In these drawings, 5TEPI indicates the starting point when the slide 6 is at the top dead center position. In this state, the gear 13 of the F mold 12 is filled with SMC material 456.

Next, 5T11) 2 +;l shows a state in which the slide 6 descends at high speed. At this time, in the hydraulic circuit diagram of FIG. 3, the first to fourth pumps Pl, P2. P3. Hydraulic oil from P- flows into the 1st to 4th hydraulic lines 31.32, 33.34
The oil is supplied to the main cylinder 4 and the sub-cylinder 7 through the sixth hydraulic line 36 and the hydraulic piping 22, 23 of the main cylinder 4 and the sub-cylinder 7. At this time, the 1.3.5.6 on-off valves 45.47, 50.51 are open, and the second and fourth on-off valves 46.49 are closed. At this time, the rod side oil of the sub cylinder 7 is returned to the tank 30 through the fifth on/off valve 50.

5TEP 3 indicates the middle speed descending state of the slide 6, and the discharge amount of the speed control servo pumps PI, P2 is controlled by the control means 2B.
Each time the slide 6 is controlled, the descending speed of the slide 6 is set to a medium speed. This switching from 5TEP 2 to 5TEP 3 is performed upon detection of the position of the slide 6 by the rotary encoder 15.

In 5TEP 4, speed control and leveling control are performed simultaneously. That is, based on the position detection of the slide 6 by the low-return encoder 15, it is switched from 5TEP 3 to STEP 4, and at this time, the lower surface of the slide 6 comes into soft touch with the upper end surface of the LONG 1 river O of the rehering cylinder 9. After that, the slide 6 is moved to the lower part of the rehering cylinder 9.
Descend while pressing 0. leveling cylinder 9
Each i-novo valve 55 is controlled so that both the secondary and fourth trees are at the same level, and the horizontality of the slide 6 is maintained with high precision.

In this 5TIiP/l, speed control servo pump P
1°P2 is controlled, and the descending speed of the slide 6 is exponentially controlled steplessly. This exponential function control will be explained in detail later. At the end of this 5TEP 4, the forming of the upper mold 11 and the lower mold 12 is completed, and the SMC material 56 in the cavity 13 is filled.

Since the slide 1'6 position at the time of completion of filling is set in advance, the speed control is switched to the next pressure control when the slide 6 position is detected by the encoder 15.

The control switching for each is indicated by 5TEP 5.

5TEII 6 +J indicates a state in which pressure control and leveling control are performed simultaneously.

That is, the discharge amount from the hydraulic pump is kept constant, and the pressure in the hydraulic circuit is controlled by the pressure control valve 48.

This pressure control is performed according to an exponential function, which will be explained in detail later. This control command is issued by the control means 28.

In the pressure control, the leveling cylinder 9 is controlled in response to pressure changes in the main cylinder 4 and the sub cylinder 7 to maintain the slide 16 horizontally.

When the compression molding is completed, the slide 6 is slightly raised through a pressure release step, and in-mold coating 1 is performed. This step is indicated by 5TEP7. The speed of this 5TIiP 7 is controlled by a servo valve 55. When raising this slide, please refer to 2.3.5.
The on-off valves 46, 47.50 are closed and the 1.4.6
On-off valves 45, 49.51 are opened. Therefore, the hydraulic oil flows from the fifth hydraulic line 35 to the sixth and seventh hydraulic lines 3.
6.37, it is supplied to the cylinder side and the rond side of the sub cylinder 7, and the 4J sub cylinder 7 becomes free. Oil in the main cylinder 4 can flow into the oil tank 2o via the full oil valve 21 by operating the change valve 52 with pilot pressure.

Then, by raising the rehering cylinder 9 via the servo valve 55 of the rehering cylinder 9, the slide 6 is raised twice.

Even when the slide I-6 is raised, the leveling cylinder 9 is controlled to maintain the horizontal state and raise the slide [6].

The rising speed and position of the slide 6 are detected by a low reencoder 15 and footbanked to the speed control.

When the in-mold coating is completed, the slide 1'6 is lowered again, and when it reaches a predetermined position, speed control is switched to pressure control. The switching is also carried out in response to pressure detection by the mold pressure sensor 14. This step is shown at 5TEI'8.

In 5TEP 8, exponential stepless pressure control is performed as in 5TEP 6, and in-molt control is performed.
Compression molding including 1. is completed. Thereafter, after the pressure is released, the slide 6 is raised to the original top dead center. This rising process is shown after 5TEI'9, and this 5TEI'9
TEP 9 and later are speed control.

When the slide is raised after 5TIEP 9, the 1.3.5th on-off valve 45, 47.50 is closed, and the 2.4.6th on-off valve 46, 49.51 is opened. Thus, the hydraulic oil is supplied to the rond side of the sub-cylinder 7 from the fifth hydraulic line 35 through the seventh hydraulic line 37. The oil on the no cylinder side of sub cylinder 7 is
The oil in the main cylinder 4 is returned to the tank 30 through the second on-off valve 46 of the sixth hydraulic line 36, and the oil in the main cylinder 4 is transferred to the full oil valve 21 by operating the change valve 52 with pilot pressure.
The oil is returned to the oil tank 20 via.

Thus, the entire compression molding process is completed.

Next, the exponential function control in the speed control will be explained.

As shown in FIG. 2.3, the following initial values are first input and set in the control means 28.

■o: Movement speed of the hydraulic cylinder (slide) before entering exponential control (constant speed at STEP 3) ZI: Slide position at the start of N speed (STEP 3 to 5T)
) 8P4 position) Z2; Slide position at which pressure control starts (position to switch from STEP 4 to 5TEP 5) α2 time constant, speed control bong P,, minimum control speed of P2, and as shown in Figure 2 As shown, the position Z of the slide 6 is set by the encoder 15.
The detected value Z and the deceleration start position 2. Compare with
If the detected value Z is higher than the deceleration start position Z1, the speed is constant V. Meteor control with speed control pumps p, , p2 so that]
I (STIEP 3).

If the above-mentioned test 1's straight line Z and deceleration start position Z1 are Z≦Z1, the deceleration pattern according to the exponential function v = (zl-Z2) -Le ''' -
--=(+)α e: Control to slow down Sly 16 by the time from the base of the natural logarithm, t, at the start of the castle series (STEP 4)
).

At this time, Bi control flow rate or speed 1. t control pump Pl
+l'2, if it is controllable, the same pump 11. ．． Control is performed with P, and in the case of small flow control, LJ,
Flow control is performed by operating the remote control relief valves 41 and 42 (at this time, the speed control pump P1.P
2 flow rate is O).

As the default value of the time constant α, ZI 72 　 　 　 ・ ・ (2) v.

There is. Using this time constant α, the constant speed range (STE
The speed transition from P3) to the deceleration region (1 to ST) 4) is l
Becomes boneless.

Figure 3.4 shows a control circuit diagram and control '60 flowchart 1 when all hydraulic pumps are variable pumps P.
-, and in this case, the switching valve 57 and the flow controller 58 are interposed in parallel in the hydraulic circuit.

If the control/A amount can be controlled by the variable pump PI, the control is performed by the same pump P1. Otherwise, in the case of small flow control, the switching valve 57 is turned on and the flow controller I/A is controlled.
The flow ffj is controlled by the roller 58 to perform the exponential function control.

By decelerating using the above-mentioned exponential function, -
Because the deceleration of the slide 6 at the time (STIiP4) becomes smoother and a uniform material flow can be obtained,
The pressure in the next process can be controlled under optimal conditions, and high-quality molded products can be obtained. In addition, the slow speed position Z1,
By changing the time constant α, it is possible to set the optimum molding conditions for various resins.

Next, the exponential function control in the pressure control will be described in detail.

First, as shown in FIG. 5, this control is performed at a constant pressure for a certain period of time after the start of the pressurization i1i control (STIiP5). After holding the exponential function 1) −11,+(Po−哩))e−β −
= -(3)l), pressure Po of pressure cylinders 4 and 7; initial pressure l"l; 1 ball force β at the end of compression molding; diagonal constant 1; change the set value based on time do.

In the exponential function control circuit, the control means 28 sends an electric signal corresponding to the equation (3) to the relief valve (electromagnetic proportional pressure control valve) 48 to adjust the hydraulic pressure of the cylinders 4 and 7 to the set pressure. It is done by controlling.

Note that P in equation (3). , Pl, and β are determined depending on the resin.

In pressure control, the reason for using the (3) second exponential function is
This is because the pressure fluctuation within the mold shown in FIG. 11 matches an exponential function.

Therefore, by performing pressure control using an exponential function, it is possible to apply a pressing force that corresponds to each state of the resin, which undergoes expansion-contraction = hardening state changes during compression molding, resulting in high-quality molding. You can get the goods.

Note that the present invention is not limited to the above embodiments.

(Effects of the Invention) According to the invention set forth in claim 1, the deceleration of the hydraulic cylinder when pressurizing is lowered becomes smooth, a uniform material flow can be obtained, and the resin processed product is uniformly deposited into the mold cavity. Since it can be filled, the pressure in the next process can be controlled under optimal conditions, and a molded product of good quality can be obtained.

According to the invention as claimed in claim 2, the resin molding 1. ′
In order to control the pressurizing force corresponding to the expansion-shrinkage-hardening reaction that occurs in l, molding can be performed under optimal pressurizing conditions.
Good quality molded products can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a press operation diagram showing an embodiment of the present invention, Fig. 2 is a graph showing the relationship between the slide position and time of deceleration control in speed control, Fig. 3 is a control circuit diagram, and the fourth round 5 is a graph showing the relationship between pressure and time during pressure control, FIG. 6 is a constant cross-sectional front view of a compression molding machine used in an embodiment of the present invention, and FIG. Figure 8 is a hydraulic circuit diagram of the main cylinder, Figure 8 is a hydraulic circuit diagram of the rehering cylinder, Figure 9 is an operation flow diagram showing the compression molding process, and Figure 10 is a stroke diagram showing the conventional compression molding control method. Time-time and pressure-time diagrams, Figure 11 is a pressure-■)° quantity diagram showing the pressure inside the mold, and Figure 12 is a slow-I/low-cooking time diagram that does not show the conventional multi-stage deceleration control. It is. 4.7...Hydraulic syringe, 11. ．． 12...Mold, 1
3. Capacity, 14... Mold pressure sensor, 15... Encoder, 25. Hydraulic unit, 28. Control means. Patent Applicant Kobe Steel Co., Ltd. Agent Patent Attorney Yasu 1) Toshi Yuaki RidllB N Separating Makudan H Processing X ”'-0(). shi) Nu (Hase Kakusajo) Mi, Thea 04-

Claims (2)

[Claims] (1) When one of a pair of molds is moved by a hydraulic cylinder and a resin processed product is compression molded in the cavity between the molds, the hydraulic cylinder is moved until the workpiece starts to be pressurized. In a compression molding machine control method in which the speed is controlled and the pressurizing force of the hydraulic cylinder is controlled after the start of pressurization, the deceleration control in the speed control before switching from the speed control to the pressure control is performed by controlling the moving speed V of the hydraulic cylinder. , V=(Z_1-Z_2)(1/α)e^-^(^1^/
^α^)^tZ_1; Stroke position of the hydraulic cylinder at the start of deceleration control Z_2; Stroke position α of the hydraulic cylinder when switching from speed control to pressure control; Time constant e; Base of natural logarithm t; From the start of deceleration control A method for controlling a compression molding machine, characterized in that it is controlled in a time of . (2) When one of a pair of molds is moved by a hydraulic cylinder and a resin processed product is compression molded in the cavity between the molds, the hydraulic cylinder is not moved until the workpiece starts being pressurized. In a compression molding machine control method that controls the speed and controls the pressurizing force of a hydraulic cylinder after the start of pressurization, the pressure control is performed by maintaining a constant pressure P_0 for a certain period of time T_0 after the start of pressure control, and then The pressure P is P=P_
1+(P_0-P_1)e-^(^1^/^β^)^t
P_1; Pressure β of a hydraulic cylinder at the end of compression molding; Time constant e; Base t of natural logarithm; A control method for a compression molding machine, characterized in that control is performed using the time from after a certain time T_0 has elapsed.