JPS6331935Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a high-frequency welder device that uses high-frequency dielectric heating to weld polymeric materials.

Conventionally, a high frequency welder apparatus is constructed as shown in FIG. That is, the high frequency output from the high frequency power supply 1 is applied between the upper electrode 2 and the base 3 which is the lower electrode, and the two polymer materials 4 and 5 sandwiched between the electrode 2 and the base 3 are heated by high frequency dielectric. Join and weld. In this case, the electrode 2 is pressed onto the polymeric materials 4, 5 by a press 6, as shown in FIG. In such a conventional high frequency welding device, the pressure of the press 6 is kept constant, and the heating operation is completed according to the intermittent operation of the high frequency power source 1 by a timer.

When the polymer materials 4 and 5 are heated by high-frequency dielectric heating, their hardness changes, and if the pressure of the press 6 is constant, the sinking speed of the electrode 2 changes. Normal thermoplastic materials soften at high temperatures, so the rate of sinking increases as the temperature rises. As the amount of sinking increases, electrode 2 and base 3
The distance between the two electrodes becomes shorter and the electric field becomes stronger, increasing the heating effect and increasing the rate of temperature rise. Therefore, in conventional high-frequency welding equipment, the rate of temperature increase of the polymeric material is low at the beginning of heating, and the rate of temperature increase increases rapidly over time. Therefore, the sinking speed of the electrode 2 is low at the beginning of heating and accelerates with time. Therefore, the timer setting at the end of the welding process must be extremely precise, and a slight deviation in the end time will result in a significant change in the welding finish. For this reason, the precision of the timer is required to be higher than necessary, and the mechanical precision of the press is maintained at a high level, which causes an increase in costs and still leaves variations in product finish.

This idea was made in view of the above circumstances.
By keeping the sinking speed of the electrode constant or limiting it to a certain value due to mechanical pressure, it is possible to prevent excessive sinking as heating progresses, and there is no need to particularly increase the accuracy of the timer. An object of the present invention is to provide a high-frequency welding device that can eliminate variations in the finish of materials.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention, in which two sheets of materials 12 and 13 to be welded, such as flat plate-shaped thermoplastic polymer materials, are placed on a base 11 which is a lower electrode. An upper electrode 14 is placed on the materials 12 and 13. This electrode 14 is connected to a pressurizing device, such as a press 16, via a connecting rod 15, and a speed sensor 17 is provided on this connecting rod 15, and the output end of this speed sensor 17 is connected to the press 16 through a servo amplifier 18. electrically connected. A high frequency power source 19 is connected to the base 11 and the electrode 14.

That is, the high frequency output from the high frequency power supply 19 is applied between the electrode 14 and the base 11, and the two sheets of welded materials 12 and 13 sandwiched between the electrode 14 and the base 11 are
are joined and welded using high-frequency dielectric heating. in this case,
When the welding materials 12 and 13 are heated by high-frequency dielectric heating, their hardness changes, and if the pressure of the press 16 is constant, the sinking speed of the electrode 14 changes. Therefore, the sinking speed of the electrode 14 is detected by a speed sensor 17, the output thereof is given to a servo amplifier 18, and the press 16 is controlled by the output of this servo amplifier 18. The servo amplifier 18
compares the output of the speed sensor 17 and the set speed value, and controls the press 16 so that the two become equal. In this way, the sinking speed of the electrode 14 can be kept constant.

Note that the control by the servo amplifier 18 may be limited so that the sinking speed of the electrode does not exceed a predetermined set value.

As described above, according to the present invention, heating is performed by adding speed control to the pressurizing system so that the sinking speed of the electrode due to mechanical pressurization does not exceed a certain limit and maintains the set speed. It is possible to provide a high-frequency welding device that can prevent excessive sinking due to the progress of welding, eliminates the need to particularly increase the accuracy of the timer, and can eliminate variations in the finish of materials.

[Brief explanation of the drawing]

FIG. 1 is a structural explanatory diagram showing a conventional high frequency welding device, FIG. 2 is a side view showing the electrode section of FIG. 1, and FIG. 3 is a structural explanatory diagram showing an embodiment of the present invention. 11...base, 12,13...material to be welded,
14... Electrode, 16... Press, 17... Speed sensor, 18... Servo amplifier, 19... High frequency power supply.

Claims (1)

[Scope of utility model registration request] A high-frequency power supply that supplies high-frequency power between a base that is an upper electrode and a lower electrode, a pressurizing device that mechanically pressurizes the upper electrode in the direction of the base, and a sinking speed that is detected by mechanically pressurizing the upper electrode. and a speed sensor that applies speed control to the pressurizing device so that the sinking speed due to mechanical pressurization of the upper electrode to which the output of the speed sensor is applied does not exceed a certain limit or maintains the set speed. A high frequency welding device characterized by comprising a servo amplifier.