JPH0451344B2 - - Google Patents

Abstract

PURPOSE:To fusion-weld synthetic resin plates by heating the whole uniformly, while the shape of a magnetic sheet is not confined by a method in which two synthetic resin plates are lapped with the magnetic sheet intervening therebetween, and a conductive metallic plate is arranged in contact with the synthetic resin plate of one side, and then an induction heating coil including plate in which the straight parallel part of an eddy-coil is buried, is arranged in contact with the synthetic resin plate of the other side oppositely to the magnetic sheet. CONSTITUTION:A mild steel net is used as a magnetic sheet 3, and a steel plate is used as a conductive metallic plate 4. When high frequency current is applied to an induction heating coil 6, the magnetic flux as shown by solid line arrows is generated, resulting in the flowing of a induction current on the metallic plate 4 and the magnetic flux as shown by dotted line is generated. The magnetic fluxes are generated in reverse direction mutually left and right from a center in between the induction heating coil 6 and the conductive metallic plate 4. When a magnetic sheet 3 is arranged in said position, said sheet is heated by hysteresis loss. Since the magnetic fluxes pass uniformly through the magnetic sheet 3, the entire sheet is heated uniformly. The load caused by a press 9 is applied thereto simultaneously with the energizing of high frequency current, whereby the synthetic resin plates are uniformly welded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for welding synthetic resin plates to each other over a wide area using high-frequency induction heating.

[Conventional technology]

In order to weld thermoplastic synthetic resin plates to each other over a wide area using induction heating, as shown in FIG. An induction heating system in which an induction heating coil 6 is embedded in a heat-resistant insulating resin plate such as epoxy resin or epoxy resin, with linear parallel parts 6a formed opposite two parts of each turn, and an induction heating coil 6 wound spirally along the surface of the plate. A plate 5 with a built-in coil is placed on it, a thermoplastic synthetic resin plate 2, a metal net 3, and a thermoplastic synthetic resin plate 1 are placed on top of it in order, and a pressure plate 7 is placed on top of the plate 5, and a high frequency current is passed through the induction heating coil 6. A conceivable method is to heat the metal net 3, press the pressure plate 7 toward the pedestal 8 with a pressure press 9, and weld the two synthetic resin plates 1 and 2 through the holes of the metal net 3. However, in this method, the current flowing in the metal mesh 3 draws a closed loop as shown by the arrow in FIG. 6, and the current does not flow in the corners of the square metal mesh 3. This is because the current that flows in a closed loop tends to flow over a short distance. For this reason, the entire metal net 3 cannot be uniformly heated without generating Joule heat at the corners, and the synthetic resin plates 1 and 2 cannot be uniformly welded over the entire welding surface.

[Problem that the invention seeks to solve]

As described above, the present invention arranges a magnetic sheet between two synthetic resin plates, heats the magnetic sheet using high frequency induction heating, and melts the two synthetic resin plates with the heated magnetic sheet. It is an object of the present invention to provide a synthetic resin welding method and apparatus that can uniformly heat the entire magnetic sheet without any restrictions on the shape of the magnetic sheet and uniformly weld the entire welding surface when welding the magnetic sheet.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention stacks two synthetic resin plates with a magnetic sheet in between, and places a conductive metal plate in contact with one synthetic resin plate. was arranged, and at least one straight parallel part of an induction heating coil wound in a spiral shape was buried in the insulating board along the surface of the board to form a straight parallel part facing the two parts of each turn. A plate with a built-in induction heating coil is placed in contact with a synthetic resin plate on the other side so that the straight parallel part of one side embedded in the insulating plate faces the magnetic sheet, and a high-frequency current is applied to the induction heating coil. A method of welding synthetic resin plates by supplying and press-welding two synthetic resin plates, and a conductive metal plate on one side of the opposing pressure surface of a pressure press, and a method of welding each turn along the surface of the plate within an insulating plate. A synthetic resin plate having a built-in induction heating coil, in which at least one straight parallel part of an induction heating coil wound in a spiral with straight parallel parts facing each other formed in two parts is embedded, is arranged on the other side of the pressurizing surface. The present invention provides a plate welding device.

In the present invention, a thin plate or mesh made of iron or magnetic stainless steel is used as the magnetic sheet interposed between the two synthetic resin plates, but since heat generation is utilized, iron is inexpensive and suitable for the purpose of use. Matching boards are easily available. The thin plate can be either perforated or non-perforated. For plates without holes, the plates are coated with a hot-melt adhesive, and the synthetic resin plates are bonded via this adhesive. In the case of perforated plates and meshes, two synthetic resin plates are mainly welded together through holes or meshes.

As the conductive metal plate used in the present invention, a plate made of copper or aluminum, which has good conductivity and is not magnetic, is generally used.

The induction heating coil generally uses a copper tube that is used as a high-frequency heating conductor and is capable of passing cooling water.

A board with a built-in induction heating coil is a board made of heat-resistant insulating resin such as phenolic resin or epoxy resin, which is wound in a spiral shape by forming straight parallel parts facing the two parts of each turn along the surface of the board. At least one side of the induction heating coil is buried at the rear of the straight line. Of course, the two straight parallel parts may be embedded in the heat-resistant insulating resin plate, or the entire spiral part may be embedded. This vortex may be an oval vortex as shown in FIG. 2, or a rectangular vortex.

The conductive metal plate and the plate with a built-in induction heating coil may be curved along a gentle cylindrical or spherical surface along the welding surface.

[Effect]

As shown in FIG. 3, a conductive metal plate 4 is placed in parallel with the induction heating coil 6 formed as described above at an interval, and when a high frequency current is passed through the induction heating coil 6, the induction heating coil 6 is heated. The current flowing through 6 generates lines of magnetic force as shown by solid arrows. In the conductive metal plate 4 located within the lines of magnetic force, an induced current flows due to the lines of magnetic force, and the induced current generates lines of magnetic force as shown by dotted arrows. These two lines of magnetic force cancel each other because their directions are opposite to each other at the center of the induction heating coil 6, and the lines of magnetic force between the coil 6 and the conductive metal plate 4, which are directed toward the outside or inside of the coil 6, mutually cancel each other out. As a result, as shown in FIG. 4, lines of magnetic force in opposite directions are generated between the induction heating coil 6 and the conductive metal plate 4, as shown by solid arrows from the center to the left and right. If the magnetic sheet 3 is placed parallel to the line of magnetic force, that is, between the conductive metal plate 4 and the straight parallel part 6a on one side of the induction heating coil 6, the current flowing through the conductive heating coil 6 can be reduced. As the polarity changes, the directions of the lines of magnetic force are alternately reversed, and the magnetic sheet 3 generates heat due to hysteresis loss. As long as the magnetic sheet 3 is placed at a position corresponding to the linear parallel portion 6a on one side, the lines of magnetic force uniformly pass through the magnetic sheet 3, so the entire magnetic sheet 3 generates heat uniformly. be done. Therefore, the magnetic sheet 3 can be heated uniformly regardless of its shape, such as square, triangle, circle, or ellipse. From the viewpoint of efficiency, it is desirable that the winding surfaces of the conductive metal plate 4 and the induction heating coil 6 are parallel to each other, but they may be arranged at a slight angle to each other. This induction heating coil 6 is buried in an insulating resin plate in order to uniformly pressurize the resin plates that are welded together, and to keep the distance between the induction heating coil 6 and the magnetic sheet 3 as small as possible. This is to enable efficient use of magnetic lines of force.

[Example] A copper tube with an outer diameter of 4 mm and an inner diameter of 3 mm was used as the induction heating coil 6, and as shown in FIG. It was wound in an oval spiral shape with 5 turns along a plane with a distance between the wires of 15 mm. This was buried along the surface of the epoxy resin plate with a thickness of 6 mm so that the parallel straight part was buried.Plate 5 with built-in induction heating coil
was formed. Vertical as synthetic resin plates 1 and 2 to be welded
Two polypropylene plates 200 mm wide, 300 mm wide, and 5 mm thick were used. 200mm long as magnetic sheet 3,
A 150-mesh wire mesh made of mild steel wire with a width of 50 mm and a diameter of 0.5 mm was used. Vertical and horizontal as conductive metal plate 4
A copper plate of 200 mm and 5 mm thickness was used.

As shown in Fig. 1, place this plate 5 with a built-in induction heating coil on a pedestal 8, and extend the synthetic resin plates 1 and 2 by 50 mm.
, and the magnetic sheet 3 was inserted between them so that the magnetic sheet 3 was positioned on the straight parallel portion 6a on one side. Furthermore, a conductive metal plate 4 is placed on top of it.
Place it so that it overlaps the induction heating coil built-in board 5,
A pressure plate 7 was placed on top of it. The high frequency current passed through the induction heating coil 6 was 450 KHz, 150 A, and the oscillation time was 5 seconds. 200〓 to the pressure plate 7 by the pressure press 9 while passing a high frequency current. A load of f was applied toward the support table 8, and after 5 seconds of electricity had ended, it was cooled for 10 seconds.

As a result, the parts of the two synthetic resin plates with the magnetic sheet 3 interposed therebetween were uniformly and completely welded, and there were no parts where welding was incomplete due to insufficient heating or parts where welding was insufficient due to insufficient heating.

〔Effect of the invention〕

According to the present invention, when welding a large area of a synthetic resin plate with a magnetic sheet interposed on the welding surface, the magnetic sheet of the desired shape along the welding surface is used to uniformly weld the entire surface. can.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of one embodiment of the device of the present invention;
The figure is a plan view of the plate with a built-in induction heating coil in Figure 1, Figure 3 is an explanatory diagram of the action of the conductive metal plate, and Figure 4 is an illustration of the direction of the magnetic lines of force generated between the conductive metal plate and the induction heating coil. The explanatory diagram, FIG. 5, is a cross-sectional view for explaining the welding method based on the conventional concept, and FIG. 6 is an explanatory diagram of the loop-shaped current generated in the metal mesh of FIG. 5. 1, 2...Synthetic resin plate, 3...Magnetic sheet,
4... Conductive metal plate, 5... Induction heating coil built-in plate, 6... Induction heating coil, 7... Pressure plate, 8...
...Case, 9...Pressure press.

Claims (1)

[Claims] 1. Two synthetic resin plates are stacked with a magnetic sheet sandwiched between them, a conductive metal plate is placed in contact with one of the synthetic resin plates, and a conductive metal plate is placed inside the insulating plate on the surface of the plate. A board with a built-in induction heating coil, in which at least one straight parallel part of an induction heating coil wound in a spiral with a straight parallel part facing two parts of each turn is buried therein, is buried in the insulating board. A synthetic resin plate whose linear parallel portion on one side is placed in contact with a synthetic resin plate on the other side so as to face the magnetic sheet, and a high frequency current is supplied to an induction heating coil to press the two synthetic resin plates. Welding method. 2. A conductive metal plate was wound in a spiral shape on one side of the opposing pressure surfaces of the pressure press, with straight parallel parts formed along the surface of the plate and facing two parts of each turn inside the insulating plate. A welding device for synthetic resin plates, wherein a plate with a built-in induction heating coil in which a straight parallel portion of at least one side of the induction heating coil is embedded is disposed on the other side of the pressurizing surface.