JP2016141101A - Heat welding device - Google Patents

Abstract

TECHNICAL PROBLEM: To stabilize weld strength by suppressing the variation of heat generation temperature of a heat welding edge in a heat welding device at the time of heat-welding a chip material such as a filter to a thermoplastic resin product.SOLUTION: A heat welding edge 3 having a weld shape outline is projected at a tip of a heat welding chip body 2, a bridge 5 for applying electricity is provided in a space surrounded by the heat welding edge 3, and an applied current is divided into three parts on the heat welding edge 3 side and the bridge 5 side by the action of the bridge 5, whereby the variation of heat generation temperature over the whole circumference of the heat welding edge 3 is suppressed to a small level to uniform the weld strength.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apparatus for thermally welding chip materials such as various filters to a thermoplastic resin product (hereinafter referred to as “thermoplastic resin product”) molded with a thermoplastic resin.

Usually, when fixing a sheet-like object to be fixed such as a resin film or cloth (hereinafter referred to as “an object to be fixed”) to a thermoplastic resin product, an adhesive or a double-sided adhesive tape is often used. When heat resistance, durability, and airtightness are required, a thermal welding (thermal fusion) method is used.

At this time, it is known to use a heat welding device that generates heat by an impulse method as a device that generates heat quickly and can immediately cool and fix the welded portion after the welding process (Patent Document 1).

However, in the case of the circular heat welding edge 3 shown in FIG. 6 and FIG. 7 attached to this document, the outer diameter is about φ10 mm (in the case of a rectangle, 8 mm × 8 mm) or less. In this case, since the heat generation portion of the heat welding edge 3 has a narrow heat generation range, variation in heat generation on the circumference of the heat welding edge 3 is not a big problem, but the outer diameter of the heat welding edge 3 portion is φ10 mm. When the diameter becomes larger, the temperature of both side parts closer to the power feeding part is lower than the middle part on the circumference of the thermal welding edge 3 compared to the middle part. Problems occur.

This is because the heating current flows from the power feeding part (+ pole) to the power feeding part (− pole) side in the shortest distance, so that the amount of heat generated on the power feeding part side is smaller than the central part of the heat welding edge 3. This is because the heat on the heat generating part side is transferred to the side wall side of the heat-welded chip body 2 and the amount of heat released from the side wall side is increased.

As a countermeasure against heat generation unevenness of the circumferentially shaped heat-welded edge, Patent Document 2 discloses two opposing locations on a ring-shaped heater as a container heat-sealing device for heat-sealing the peripheral edge of the container and the lid. There is disclosed a heater that is provided with a power feeding unit and that allows uniform heat generation by making the inner and outer dimensions of the power feeding unit different in the circumferential direction. However, since this heater is a thin plate, the heat generation temperature can be easily controlled, but the rigidity against the pressing force at the time of welding is low, so that a metal suppression means via a silicone rubber for heat insulation is necessary. In addition, since the heat resistance of silicone rubber is about 200 ° C., it is difficult to weld a resin that needs to be heated to 200 ° C. or more. Further, since silicone rubber is flexible, the movable dimensional accuracy of the heater in the pressing direction is ensured. This is difficult, and can only be applied to planar welded shapes such as seals between films.

Further, in Patent Document 3, a portion that divides the line length of the ring-shaped resistance heating element into an even number is set as a power receiving unit, and the power receiving unit adjacent to the power receiving unit is set as a different pole, and then the same polarity is gathered together. A thermoplastic resin welding device formed by forming a voltage application electrode is disclosed. Although this welding apparatus is excellent in the heat generation balance of the resistance heating element, since it is impossible to eliminate heat radiation from each power supply unit provided even times, a temperature drop in the heat generation part adjacent to the power supply unit is unavoidable.

Further, as a heating apparatus for bonding, Patent Document 4 includes a heat sink composed of a rectangular tube having a hollow portion, and the bottom surface is transmitted through a resistor that generates heat by energizing the lower open end surface of the heat sink. There has been disclosed a proposal of a technique for securing rigidity of a welded portion by combining a heat member to improve overall rigidity. However, since this heating element has a structure in which a feeding portion is provided on two opposite faces of the square tube and energizes, the two faces against the current flowing in the resistor that contacts the two current-carrying parts that are not adjacent to the feeding part. Since the current flowing through the resistor in contact with the power supply section is biased, the heat generated by the resistor becomes non-uniform.

Japanese Patent No. 5592911 Japanese Patent No. 3857619 JP-A-11-179808 JP 9-225632 A

The present invention is a thermal welding apparatus that welds a product having a contour shape in the welded portion, which has excellent dimensional accuracy, reduces unevenness in the heat generation temperature distribution at the welded edge portion, and additionally shortens the welding cycle time. An object of the present invention is to provide a heat welding apparatus that can be used.

In order to achieve the above-mentioned object, the invention according to claim 1 is an impulse heating type thermal welding in which a periphery of a chip material formed of a material having thermal weldability is thermally welded to a thermoplastic resin product in a thermal welding apparatus. A thermal welding edge having a contour of the welding shape is protruded from a tip portion of the thermal welding chip body of the thermal welding apparatus, and the thermal welding chip body surrounded by the welding edge is provided inside the thermal welding chip body. Forming a space, and by providing a bridge so as to cross the space, a current flow applied from the left and right electrode portions flows along the welding edge and along the bridge. The variation in the heat generation temperature of the heat welding edge is set to be small by dividing the current flow into three.

Furthermore, the invention according to claim 2 is the thermal welding apparatus according to claim 1, wherein the shape of the thermal welding edge in a front view is formed in a circle, a rectangle, or a polygon. It is.

Further, the invention according to claim 3 is the thermal welding apparatus according to claim 1, wherein a cooling air supply pipe is inserted into the thermal welding tip body, and a side wall of the thermal welding tip body is provided. A cooling air outflow slit is formed in the middle of the left and right electrode portions, and a cooling air outflow window is formed in the circumferential direction at the lower end of the slit, and the cooling air ejected from the cooling air supply pipe is the thermal welding tip. The heat welding edge portion is cooled from the inside of the main body, and then flows out of the heat welding chip main body through the slit and the cooling air outflow window.

Furthermore, the invention according to claim 4 is the thermal welding apparatus according to claim 1, wherein the bridge traverses the center of the space portion in the main body of the thermal welding chip, and the bridge has a width of the central portion at both ends. It is characterized by being set larger than the width.

In the thermal welding apparatus according to the present invention, the bridge is formed so as to cross the central portion in the inner diameter of the thermal welding edge of the thermal welding tip main body, so that the current flows between the current flowing through the bridge and the edge sides on the both sides. Divided into three currents. As a result, the variation in the heat generation temperature can be alleviated in the entire periphery of the heat welding edge.

In particular, in the case of a heat-welded tip having an outer diameter of approximately 10 mm or more than approximately 8 mm × 8 mm in the case of a rectangle, stable heat-welding can be achieved by reducing variations in the heat generation temperature. The welding time can be shortened by cooling. In addition, since the bridge portion can be easily formed at the front end portion of the heat-welded chip body, the manufacturing cost is low, and the maintenance is easy due to the simple configuration.

It is a perspective view of a heat welding apparatus. It is a front view of a heat welding apparatus. It is a center longitudinal section front view of a heat welding apparatus. It is a front view when a heat welding apparatus is seen from the lower part. The heat welding process of Example 1 is shown, (a) is before welding, (b) is the state immediately before the start of welding, (c) is the state at the end of welding, and (d) is the heat welding after the welding is completed. It is explanatory drawing which shows the state which the apparatus left | separated from the chip | tip material. It is a front view of the welding apparatus of patent document 1. FIG. It is a center longitudinal cross-sectional front view of the heat welding apparatus shown in FIG. It is a perspective view of the heat welding apparatus which consists of a rectangular heat welding edge. It is explanatory drawing of the temperature distribution by the heat_generation | fever simulation of this invention heat welding chip | tip main body, Comprising: (a) is a perspective view, (b) is the front view seen from the heat welding edge side. It is explanatory drawing of the temperature distribution by the heat_generation | fever simulation of the heat welding chip | tip main body of the prior art example shown to FIG. 6, 7, (a) is a perspective view, (b) is the front view seen from the heat welding edge side.

The heat welding apparatus of the present invention is used when directly fixing an object to be fixed to the surface of a thermoplastic resin product. For the purpose of fixing a sheet-like object to be fixed to a thermoplastic resin product, the shape of the thermoplastic resin product and the object to be fixed is not limited, and the surface of the thermoplastic resin product is a curved shape or the shape of the object to be fixed is The present invention can be applied to circular, rectangular, polygonal, and other arbitrary shapes. In addition, by applying a radius (R) or a gradient to the thermal welding edge of the thermal welding equipment, it can also be used for thermal caulking when deforming contour ribs and protrusions formed on thermoplastic resin products and fixing parts. Can be used.

When the object to be fixed is a thermoplastic resin, it is a condition that the heat melting temperature is almost the same as that of the thermoplastic resin product. Furthermore, since the molten thermoplastic resin product can be fixed if it soaks into the fixed object, the fixed object itself is not heat-meltable, but there is a cloth or non-woven fabric having voids from the surface to the inside. The present invention can also be applied to fixing a filter (material is cloth, non-woven fabric, glass fiber, felt, porous resin, etc.).

The first embodiment is an embodiment of the invention described in claims 1 to 4, and the configuration and welding process will be described in detail based on FIGS. 1 to 5 (a) to (d).

1 is a perspective view of the heat welding apparatus 1 as seen from the front, FIG. 2 is a front view, FIG. 3 is a front view of the center longitudinal section, FIG. 4 is a front view as seen from the heat welding edge side, and FIGS. d) It is explanatory drawing of a welding process.

In the thermal welding apparatus 1, a ring-shaped thermal welding edge 3 protrudes from the tip of a cylindrical thermal welding chip body 2, and an inner space surrounded by the thermal welding edge 3 is one step higher than the thermal welding edge 3. A bridge 5 for energization is provided in a horizontal position.

The bridge 5 is installed in parallel with the energization direction of the thermal welding edge 3, and the width (cross-sectional area) of the connecting portion 5 a with the thermal welding edge 3 is set smaller than the width (cross-sectional area) of the intermediate portion of the thermal welding edge 3. In addition, a gap 6 that is widened to the maximum in a range in which a certain gap can be secured between the intermediate portion 5b of the bridge 5 and the heat welding edge 3 is provided. For this reason, since the electrical resistance is small in the central portion of the bridge 5 and the electrical resistance of the connecting portion 5a is large, the bridge 5 generates a large amount of heat on the connecting portion 5a side at both ends, and generates a small amount of heat on the intermediate portion 5b side. For this reason, the surface of the filter 12 is not easily affected by heat generated by the bridge 5.

Further, since the cross-sectional area of the connecting portion 5a of the bridge 5 is smaller than the cross-sectional area of the heat-welding edge 3, the amount of heat generated by the connecting portion 5a of the bridge 5 is larger than that of the heat-welding edge 3. In order to escape by heat transfer to 2b, the heat welding edge 3 is controlled to a substantially uniform temperature over the entire circumference.

Here, the result of analyzing the amount of heat generated at the connecting portion 5a of the thermal welding edge 3 and the bridge 5 and the amount of heat transferred to the power feeding side 2b using thermal fluid analysis software (CFdesign (Blue Ridge Numerics, registered trademark of Incorporated)). Is shown in FIGS. 9 (a) and 9 (b). As is clear from this analysis result, the temperature difference of the heat generation temperature distribution of the thermal welding edge 3 is within 20 ° C.

Reference numeral 8 denotes a cooling air outlet window formed horizontally on both side surfaces of the thermal welding edge 3 in the thermal welding tip body 2, and 7 denotes a center of the outlet window 8 on the front and rear sides of the thermal welding tip body 2. A slit formed in a symmetric position upward from 9, 9 and 9 a are lead wires for voltage application, and 10 is through a central hole of a ceramic insulator 11 fitted in the upper end portion of the heat-welded chip body 2. A cooling pipe 10 for supplying cooling air inserted into the heat-welded chip body 2.

The rear end of the cooling pipe 10 is connected to a compressed air supply device (not shown), and the jet of the compressed air is controlled by a controller (not shown).

Although the heat welding apparatus 1 can be operated by hand, it is usually attached to the tip of an actuator (not shown) that can be moved up and down installed on a gantry (not shown). The heat welding apparatus 1 can also be used by being attached to an automatic heat welding apparatus that is performed at a plurality of locations using a three-axis controlled air cylinder, electric cylinder, or robot.

Next, the welding process will be described using [FIG. 5] (a) to (d).

12 is a filter to be welded, 13 is a thermoplastic resin product made of ABS, and 14 is a vent hole having a hole diameter of φ14 mm provided in the thermoplastic resin product 13. Attached to the entrance.

The filter 12 in this embodiment is (porous membrane made of PTFE) t = 0.3 mm φ22.0 mm.

The thermal welding edge 3 of the thermal welding chip body 2 has an outer diameter of φ20.0 mm and an inner diameter of φ18.0 mm.

[FIG. 5] (a) is a state in which the thermal welding apparatus 1 is on standby above the filter 12 disposed at the inlet portion of the vent hole 14 of the thermoplastic resin product 13.

[FIG. 5] (b) is a state in which the thermal welding apparatus 1 descends toward the thermoplastic resin product 13 and the thermal welding edge 3 is in contact with the surface of the filter 12, and this state is the thermal welding tip body. 2 is a state in which the filter 12 is sandwiched between the thermal welding edge 3 and the thermoplastic resin product 13. Here, when a voltage is applied to the lead wires 9 and 9a from a power supply device (not shown), the heat welding edge 3 of the heat welding chip body 2 generates heat due to electric resistance. At the same time, an appropriate pressing force is applied to the heat welding device 1 in the direction of the thermoplastic resin product, so that the heat welding edge 3 of the heat welding chip body 2 is in pressure contact with the filter 12.

The heat generated from the heat-welding edge 3 heats the filter 12 and at the same time heat is transferred to the thermoplastic resin product 13 through the filter 12 to heat the thermoplastic resin product 13, so that the thermoplastic resin product 13 is softened, It melts when it reaches the melting temperature.

In order to accurately control the heat generation temperature of the heat-welded chip body 2, it is effective to properly manage the heat generation temperature by attaching a thermocouple to the heat generating portion, detecting the heat generation temperature, and performing feedback control.

[FIG. 5] (c) shows that the molten thermoplastic resin product 13 is welded edge 3 together with the filter 12.
At the same time, a part of the molten resin is squeezed by the pressure of the filter 12 (porous membrane) and then cooled and solidified by the cooling air from the cooling air pipe 10, so that the filter 12 is thermoplastic. In this state, the resin product 13 is integrally fixed to the inlet of the vent hole 14.

Further, in this fixed state, the filter 12 sinks into the surface of the thermoplastic resin product 13 by the pushing force of the heat welding edge 3 of the heat welding chip body 2.

Further, the heat welding edge 3 applies a force that pushes the filter 12 from the center to the outer circumferential direction when descending (when sinking), so the filter 12 is not wrinkled and is welded cleanly. Will do.

The lowered position of the heat welding apparatus 1 is set in advance, and the lowered position is a space where the welded portion of the filter 12 is not damaged when the thermoplastic resin product 13 is melted and impregnated into the filter 12 and integrated. Select a value that can be secured. In the present embodiment, a space of 0.15 mm was set in the welded portion 12a with respect to a thickness of the filter 12 of 0.3 mm.

Up to this point, the bridge 5 does not come into contact with the filter 12 and heat generation due to energization is small, so there is no possibility of scratching the filter 12 or causing damage due to heat.

After the set heating time has elapsed, the controller switches the electromagnetic valve so that the cooling air 10a is supplied from the cooling air pipe 10 provided in the heat-welded chip body 2 at the same time as the application of voltage is stopped. The jetted cooling air cools the tip of the heat-welded chip body 2 from the inside.

In this way, the cooling air that has flowed out of the cooling air pipe 10 is discharged to the outside of the welding tip body 2 through the gap between the outflow window 8 and the slit 7.

When the heat welding edge 3 and the bridge connecting portion 5a of the heat welding tip body 2 are cooled for a preset time and the resin of the welding portion 12a is solidified, the controller switches the solenoid valve to stop the supply of cooling air, and the heat welding device 1 To raise. As a result, the filter 12 is welded around the inlet of the vent hole 14 of the thermoplastic resin product 13 and fixed as shown in FIG.

FIGS. 9 (a) and 9 (b) show the simulation results of changes in the heat generation temperature when the heat-welded chip body 2 (heat-welded edge 3) according to the present invention generates heat. As shown in this figure, the temperature distribution of the thermal welding edge 3 is in the range of 130 ° C to 160 ° C. On the other hand, in the conventional example (FIGS. 6 and 7) in which the bridges of FIGS. 10A and 10B are not provided, the variation in the heat generation temperature is extremely large from 130 ° C. to 200 ° C.

In the first embodiment, the case where the circular filter 12 is heat-welded with the circular heat-welding edge 3 has been described. However, if the shape of the heat-welding edge 3 can be processed into an ellipse, a rectangle, a polygon, etc., for example, FIG. It is also possible to heat-weld in a rectangular shape using a heat-welding tip body 2 having a rectangular heat-welding edge 3 as shown.
In FIG. 8, the same reference numerals as those shown in FIGS. 1 to 5 (a) to (d) indicate the same components, and the description of the reference numerals is omitted here to avoid duplication of description. .

DESCRIPTION OF SYMBOLS 1 Thermal welding apparatus 2 Thermal welding tip main body 3 Thermal welding edge 4 Opening part 5 Bridge 5a Bridge connection part 6 Gap 7 Air outflow slit 8 Air outflow window
9, 9a Lead wire 10 Cooling air pipe 11 Insulator 12 Filter 13 Thermoplastic resin product 14 Ventilation hole

Claims (4)

An impulse heating type thermal welding apparatus that thermally welds the periphery of a chip material formed of a material having thermal weldability to a thermoplastic resin product, and the tip of the thermal welding chip body of the thermal welding apparatus is Protruding a thermal welding edge consisting of the outline of the welding shape,
A space is formed inside the heat welding chip body surrounded by the welding edge,
By providing a bridge so as to cross this space portion, the current flow applied from the left and right electrode portions is divided into three parts: a current flow flowing along the welding edge and a current flow flowing along the bridge. By doing so, the variation in the heat generation temperature of the heat welding edge was set small,
A thermal welding apparatus for thermally welding a chip material to a thermoplastic resin product. It is a heat welding apparatus of Claim 1, Comprising: The shape of the front view in the said heat welding edge is formed in circular, a rectangle, or a polygon, The heat welding apparatus characterized by the above-mentioned. 2. The heat welding apparatus according to claim 1, wherein a cooling air supply pipe is inserted into the heat welding tip body, and the side wall of the heat welding tip body is cooled between the left and right electrode portions. An air outflow slit and a cooling air outflow window are formed in the circumferential direction at the lower end of the slit, and the cooling air ejected from the cooling air supply pipe passes through the thermal welding edge portion from the inside of the thermal welding tip body. After cooling, the heat welding apparatus is characterized in that it flows out of the heat welding chip body through the slit and the cooling air outflow window. It is a heat welding apparatus according to claim 1, wherein the bridge crosses the center of the space part in the heat welding chip main body, and the bridge is set such that the width of the center part is larger than the width of both ends. A heat welding apparatus characterized by

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