JP2002153999A - Press device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press device capable of suppressing variance of the temperature of a hot plate to heat and press a printed circuit board, etc. SOLUTION: Electric heaters 16A-16F are loosely fitted to through holes 14A-14F in the hot plate to form heating flow passages 28A-28F for allowing thermal medium to flow in a space between the electric heaters. A temperature sensor 34 is provided on the hot plate, the temperature signal actually measured thereby is transmitted to a control unit 8, and the difference between the actually measured temperature and the target temperature is operated to determine the power requested for the heaters 16A-16F according to the difference. The output signal for the requested power is transmitted to a thyristor unit 35, and the power is adjusted by the thyristor and supplied to the heater. Variance of the temperature of the hot plate is suppressed by this closed feedback control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a workpiece such as a plastic IC card (integrated circuit card) or a printed circuit board (PWB).
The present invention relates to a press device for forming under pressure.

[0002]

2. Description of the Related Art The above-mentioned press apparatus is provided with a pair of upper and lower pressing plates each having a hot plate mounted thereon, a heater arranged and fixed in a hole formed inside the hot plate, and an inner wall of the hole and a heater. There is known a heating flow path formed in a gap between the outer circumference of the heating element and a heating medium such as oil. The heating of the heater detects the temperature of the hot plate and supplies power to the heater when the detected temperature is lower than the target temperature, and stops power supply to the heater when the detected temperature is higher than the target temperature. Control was done.

[0003]

As described above, when manufacturing a printed circuit board or the like which is required to have higher accuracy due to a higher density or the like, a hot plate for controlling on / off of a heater as described above is used. In temperature control, the amount of power supplied to the heater is always constant regardless of the difference between the actual temperature of the hot plate and the target temperature, so that the temperature of the hot plate can be maintained at an appropriate temperature. It is difficult, and temperature fluctuations such as continually deviating from the target temperature and repetitively moving up and down are increased, resulting in increased occurrence of defective products.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a press apparatus capable of accurately controlling the temperature of a hot plate so that the temperature does not deviate significantly from a target temperature as compared with on / off control.

[0005]

According to the present invention, there is provided a press apparatus comprising:
It has a pair of platens that can approach and separate from each other, and can press a workpiece such as a printed circuit board. A hot plate is provided between the surface plates,
The hot platen is attached to the platen or arranged between the platens so that at least one of them is interlocked with the platen so that the workpiece can be sandwiched. Further, a multi-layer structure in which one or more hot plates are further disposed between the hot plates on the side of the platen may be employed. A hole is formed inside the hot plate, and a heater is inserted into the hole. A gap having an annular cross section is formed by the inner peripheral wall of the hole and the outer peripheral portion of the heater, and the gap is formed as a heating flow path through which a heat medium such as oil flows. On the other hand, a temperature sensor for detecting a temperature related to the temperature of the hot plate and outputting an actually measured temperature signal is provided. Control the measured temperature signal output from this temperature sensor.
The control unit calculates the difference between the measured temperature and the set target temperature, determines the amount of power required for heating the heater according to the difference, and outputs a required power output signal. The feedback control is performed as follows. Further, a thyristor unit is provided which receives a required power output signal from the control unit and supplies power to the heater while adjusting the magnitude of the supplied power with the thyristor based on the required power output signal.

In the above press apparatus, the temperature of the hot plate is detected by the temperature sensor and output to the control unit as an actually measured temperature signal. The control unit calculates the difference between the measured temperature signal and the target temperature signal. Next, the amount of power required for heating the heater is determined according to the magnitude of the difference, and a required power output signal is output to the thyristor unit. In the thyristor unit, the required power output signal is received from the control unit, the power is adjusted by the thyristor to a size corresponding to the required power output signal, and supplied to the heater. The heating medium heated in the heating flow path is heated by the heater thus heated, and the heating plate is heated by heat transfer by the heating medium. Therefore, with the above configuration, it is possible to perform closed feedback control in which the amount of electric power supplied to the heater is supplied to the heater while constantly adjusting the magnitude thereof according to the temperature condition of the hot plate. Variations in temperature can be reduced as compared with the on / off control.

[0007] The temperature sensor is preferably mounted on one of the pair of stools, and controls the electric power supplied to the electric heaters on both stools based on the measured temperature signal of the temperature sensor. This makes it possible to control the electric heaters of the hot plates on both platens with one temperature sensor.

The heating passage is preferably connected to a cooler, and when the measured temperature of the heating plate or the temperature of the heating medium is higher than a predetermined value, the heating medium flowing out of the heating passage is guided to the cooler. When the value is equal to or less than the value, the heat medium is switched so as to bypass the cooler. This makes it possible to control the temperature of the hot plate by the thyristor unit and to quickly lower the temperature of the heat medium by guiding the heat medium to a cooler and cooling it during overheating. As a result, the heated hot plate can be quickly lowered to the target temperature, and more precise control can be performed.

Preferably, the predetermined value is set so as to have a hysteresis between a temperature at which the heat medium is introduced into the cooler and a temperature at which the cooler is bypassed. As a result, hunting for switching the cooler can be prevented, and stable operation can be ensured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows the entire press apparatus 1.
In the drawing, a fixed platen 3 is fixed to an upper portion of a frame 2 and a movable platen 4 is provided below the fixed platen 3 in the press device 1. The movable platen 4 can be moved up and down by a hydraulic cylinder 5. The hydraulic cylinder 5 is connected to a hydraulic source 7 such as a hydraulic pump via a hydraulic pipe 6, and oil is supplied and discharged by a switching valve 17 provided in the hydraulic pipe 6. The operation of the switching valve 17 and the hydraulic source 7 is controlled by the control unit 8. In FIG. 1, these control wires and the like are omitted. In the press apparatus 1, an upper hot plate 10 is attached to the lower surface of the fixed platen 3 via a heat insulating material 9, and a lower hot plate 12 is attached to the upper surface of the movable platen 4 via a heat insulating material 11. Have been.

FIG. 2 shows a cross section of the upper hot plate 10 on the side of the fixed platen 3, and a hydraulic circuit of the hot plate and a control circuit of the heater. Although the hot plate has a different pressing direction and the like between the upper hot plate 10 and the lower hot plate 12, both have substantially the same configuration except that the lower hot plate 12 does not have a temperature sensor described later. is there. As shown in FIG. 2, the hot plate body 13 having a rectangular parallelepiped shape is provided.
In this example, six through-holes 14A to 14F parallel to one side are formed at predetermined intervals, and the through-holes 14A to 14F are formed at predetermined intervals.
At both ends of 4F, communication through holes 15A and 15B are formed orthogonal to the through holes 14A to 14F, respectively. Therefore, each of the through holes 14A to 14F communicates at both ends through the communication through holes 15A and 15B. Electric heaters 16A to 16F smaller in diameter than these through holes are inserted into the through holes 14A to 14F, and a heating flow path having an annular cross section is formed in a gap between the inner wall of the through hole and the outer peripheral portion of the heater. 28A to 28F are formed so that oil as a heat medium flows. Here, the entrance 26, the exit 27,
The cross-sectional areas of the communication through holes 15A and 15B are the same. Also, the cross-sectional area of the heating flow paths 28A to 28F is
6, the outlet 27 and the communication through-holes 15A and 15B are set to be substantially equal to the respective cross-sectional areas, but are drawn smaller than the communication through-holes 15A and 15B in the figure.

The electric heaters 16A to 16F are provided with flange portions 18A to 18F provided at one end thereof.
3 is liquid-tight on one end side surface with a seal packing interposed therebetween, and fixed with bolts. On the other hand, at the other end of the through holes 14A to 14F of the hot plate main body 13, a columnar support member 23A having bottomed holes 24A to 24F formed.
To 23F are fixed by welding in a liquid-tight manner. These bottomed holes 24A to 24F have respective electric heaters 14A to 14A.
The other end of 14F is loosely fitted with a gap between the radial direction and the axial direction, so that the electric heater vibrates due to the flow of oil along the electric heaters 14A to 14F, and the flange portions 18A to 18F are damaged at an early stage. I try to prevent that. The radial gap between the inner peripheral portion of the bottomed hole and the outer peripheral portion of the heater, although exaggerated in the figure, has a diameter difference of about 0.2 mm to 0.4 mm in a state where thermal expansion by heating is stable. It is set to be.

From one end of each of the heaters 16A to 16F projecting outward from the flanges 18A to 18F, wirings 22A to 22F are respectively taken out and connected to the thyristor unit 35 so that power can be supplied. The thyristor unit 35 is controlled by the control unit 8 as described later. At the center of the other end of the upper heating plate 10, a temperature sensor 34 is attached, detects the temperature of the heating plate 10, and outputs a measured temperature signal to the control unit 8.
Output is possible to.

The control unit 8 includes, for example,
It is constituted by a microcomputer or the like, receives a measured temperature signal of the hot plate from a temperature sensor 34 attached to the hot plate body 13, compares the measured temperature signal with a preset target temperature of the hot plate, and determines the difference. It is designed to calculate. Next, the electric power required for the electric heaters 16A to 16F is determined based on the difference, and the electric power is output to the thyristor unit 35 as a required electric power output signal.

The thyristor unit 35 has a thyristor, receives a required power output signal from the control unit 8, and controls the output of the thyristor.
That is, a power output signal is output from the thyristor to the electric heaters 16 </ b> A to 16 </ b> F according to the required power output signal, that is, the power corresponding to the difference between the measured temperature and the target temperature. In this case, the thyristor unit 35 supplies the electric power to both the electric heater of the upper heating plate 10 and the electric heater of the lower heating plate 12. Thus, the temperature sensor 34, the control unit 8, the thyristor unit 35, the electric heaters 16A to 16F
This allows closed feedback control of the hot plate temperature. In this feedback control, PID (proportional, integral, differential) control or the like is used.

On the other hand, the hydraulic circuit for the hot plate will be described. The hot plate main body 13 has heating passages 28A to 28F formed therein and a communication through hole 15A located at one end (lower side in FIG. 2). Are left open, and in FIG.
The opening on the right end side is an oil inlet 26, and the opening on the left end side is an oil outlet 27. Further, column-shaped closing members 25A to 25G are provided at the connection portions of the communication through holes 15A and 15B connecting the adjacent through holes 14A to 14F with one end side (the lower side in FIG. 2) and the other end side. (Upper side in FIG. 2) and weld every other two to close. As a result, the through holes 14
A to 14F are arranged in series in this order, and the adjacent through holes 14A to 14F, and thus the heating flow path 28A
28F are alternately connected by a communication through hole 15A on one end side and a communication through hole 15B on the other end side. Accordingly, the oil supplied from the inlet 26 is supplied to the heating flow path 28A (from one end to the other end), the communication through path 15B at the other end, the adjacent heating flow path 28B (from the other end to one end),
One end side communication through hole 15A, adjacent heating flow path 28C (from one end side to the other end side), the other end side communication through hole 15B, adjacent heating flow path 28D (the other end side to one end side), one end Side communication through hole 15A, heating channel 28E (from one end to the other end),
The connection through hole 15B on the other end side and the adjacent heating flow path 28F (from one end side to the other end side) meander, and are finally discharged from the outlet 27.

A discharge port of a hydraulic pump 30 driven by an electric motor 38 is connected to an inlet 26 of the hot plate body 13 through a hydraulic pipe 29, and a hydraulic pipe 29 is connected to an outlet 27 to The oil can be supplied and circulated by connecting to the suction port of the pump 30. Upstream of the suction port of the hydraulic pump 30 is a tank 39 for adjusting thermal expansion.
Are connected to adjust the volume change due to the temperature expansion of the oil in the hydraulic circuit. Further, a branch pipe 32 is provided which branches from a middle of a hydraulic pipe 29 connecting the outlet 27 of the hot plate body and the hydraulic pump 30, and an oil cooler 33 in the branch pipe 32 upstream of the hydraulic pipe 29 to the hydraulic pump 30. They are joined. 33a is an oil inlet of the oil cooler 33, 33b is an oil outlet, 33c is a cooling water outlet, and 33d is a cooling water inlet. A switching valve 31 (three-way valve) is provided at the branch portion,
The oil discharged from the outlet 27 is returned directly to the hydraulic pump 30 through the hydraulic pipe 29 or flows to the branch pipe 32 and is cooled by the oil cooler 33.
It is possible to switch to return to. Control·
The unit 8 opens the branch pipe 32 when the temperature detected by the temperature sensor 34 becomes higher than a predetermined value, sends the oil discharged from the outlet 27 to the oil cooler 33, and cools it.
If the temperature is equal to or lower than the predetermined value, it is determined that the oil from the outlet 27 is prevented from flowing into the branch pipe 32 and returned directly to the hydraulic pump 30. A control signal based on this determination result is sent to the switching valve 31, and the switching of the oil flow by the switching valve 31 is enabled. In this case, it is preferable that the predetermined value is provided with a hysteresis between temperatures at which the switching valve 31 is opened and closed. That is, the switching valve 31 is opened so that the branch pipe 32 is opened and the oil flows to the oil cooler 33.
The predetermined temperature at which the switching valve 3 is switched is set such that the branch pipe 32 is closed and the oil bypasses the oil cooler 33.
1 is set higher than the predetermined temperature at which the switching is performed. Therefore,
The former predetermined temperature is preferably set to a value higher than the target temperature, and the latter predetermined temperature is preferably set to a value lower than the target temperature. In addition, these hydraulic circuits and control circuits share the upper heating plate 10 side and the lower heating plate 12 side as shown in FIG.
Although the temperature of the upper heating plate 10 is detected, the temperature of the lower heating plate 12 may be detected. Alternatively, the temperature of each heating plate may be detected and a separate hydraulic circuit and control circuit may be used. May be provided.

Next, the operation of the above press device will be described. When the press apparatus 1 is started, the hydraulic pump 30 starts supplying oil to the hot plates 10 and 11. At the same time, since the actually measured temperature detected by the temperature sensor 34 is lower than the target temperature, the thyristor unit 35 outputs a required power output signal that has a large difference from the target temperature calculated by the control unit 8 and maximizes the required power. Send to As a result, the thyristor unit 35 includes the electric heaters 16A to 16A.
Continue to supply large electric power to F, and quickly heat the electric heater. The heating of the electric heaters 16A to 16F causes the temperature of the oil as the heat medium to rise, and the heat from the oil also causes the heat plates 10, 12 to rise in temperature. At this time,
Since the temperature of the hot plate 10 detected by the temperature sensor 34 is equal to or lower than a predetermined value, the switching valve 31 closes the branch pipe 32 and the oil discharged from the outlet 27 of the hot plates 10 and 11 is directly sucked into the hydraulic pump 30 to the suction port. The temperature is increased by increasing the temperature of the oil and the hot plate by feeding the fluid and circulating it again to the hot plates 10 and 11.

When the measured temperature reaches the target temperature, the control unit 8 outputs to the thyristor unit 35 a required power output signal for reducing the required power output so that the magnitude falls within a range from a decrease to a stop. Thereby, the thyristor unit 35 is connected to the electric heater 16.
The power supplied to A to 16F is reduced so that the target temperature does not become excessive. Thereafter, the control is shifted to control for maintaining the hot plates 10 and 12 at the target temperature. That is, the control unit 8 determines the magnitude of the required power amount according to the difference between the measured temperature and the target temperature, and inputs the required power amount to the thyristor unit 35 as a required power output signal. The thyristor unit 3 is based on the required power output signal,
Supply or stop power of a magnitude suitable for maintaining the target temperature of the hot plate, and continue the feedback control. On the other hand, while controlling the heating of the electric heaters 16A to 6F,
When the temperature of 0 is higher than a predetermined value, the branch pipe 32 is opened by the switching valve 31 and the oil is cooled by the oil cooler 33 to prevent the temperature of the hot plates 10 and 11 from becoming excessive. Maintain the temperature at the target temperature. Use of this cooler is desirable in that the temperature of the oil can be rapidly reduced. As described above, the temperature control of the hot plates 10 and 12 is performed based on the difference between the measured temperature of the hot plate 10 and the target temperature.
Since feedback control is performed, and the power supplied to the electric heaters 16A to 16F is adjusted optimally by the thyristor unit 35, it is possible to suppress the temperature of the hot plates 10, 12 from greatly varying from the target temperature.

Although the temperature sensor 34 is provided on the upper heating plate 10 in the above embodiment, it may be provided on the lower heating plate 12. Further, a temperature sensor may be provided on each of the upper and lower heating plates, and the electric heaters of the upper and lower heating plates may be independently controlled. In this case, although the cost is higher than in the case of a single temperature sensor, it is possible to perform control with higher accuracy in consideration of the difference in the state of each hot plate.

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire press apparatus of the present invention.

FIG. 2 is a diagram showing a cross section of the hot plate of FIG. 1 and a hydraulic circuit and a control circuit thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Press apparatus 3 Fixed surface plate 4 Movable surface plate 7 Hydraulic power source control unit 10 Upper heating plate 12 Lower heating plate 13 Hot plate main body 14A-14G Through-hole (hole) 15A, 15B Communication through-hole 16A-16H Electric heater 25A -25G closing member 26 inlet 27 outlet 28A-28F heating channel 30 hydraulic pump 31 switching valve 33 oil cooler 34 temperature sensor 35 thyristor unit

Claims (4)

[Claims] A hot plate is provided between a pair of approachable / separable surface plates, and a heater is inserted into a hole formed inside the hot plate,
An outer peripheral portion of the heater and an inner peripheral wall of the hole form a heating passage having an annular cross section through which a heating medium flows through a gap formed in a radial direction, and the heating medium in the heating passage is heated by the heater. In a press apparatus configured to heat the hot plate, a temperature sensor that detects a temperature related to the temperature of the hot plate and outputs an actually measured temperature signal; A control unit that calculates a difference, determines a power amount necessary for heating the heater according to the difference, and performs feedback control so as to output a required power output signal, and a thyristor; A thyristor unit that supplies the power to the heater while adjusting the amount of power supplied by the thyristor based on the required power output signal output from the unit; Further comprising a pressing device according to claim. 2. The temperature sensor is mounted on one of the pair of surface plates, and based on an actually measured temperature signal of the temperature sensor, electric power supplied to both electric heaters of the surface plate is controlled. The press device according to claim 1, wherein: 3. The heating flow path is connected to a cooler, and when the measured temperature or the temperature of the heating medium is higher than a predetermined value, the heating medium flowing out of the heating flow path is guided to the cooler. 3. The press device according to claim 1, wherein the heat medium is switched so as to bypass the cooler when the value is equal to or less than the value. 4. The press apparatus according to claim 3, wherein the predetermined value is set so as to have a hysteresis between a temperature at which a heat medium is introduced into the cooler and a temperature at which the cooler is bypassed. .