SU929439A1 - Apparatus for high-frequency welding of polymeric materials - Google Patents

Description

one

The invention relates to the welding of polymeric materials, in particular, using high-frequency heating ..

A device for high-frequency welding of polymeric materials, containing an electrode made in the form of a metal plate, is known.

The disadvantage of the device is that when welding plastics, the material being welded is thinned in the weld zone and the formation of sagging in the heat-affected zone, which leads to a decrease in the quality of the welded joint.

The closest in technical essence and the achieved result to the invention is a device for high-frequency welding of polymeric materials, containing a base with an elastic substrate fixed on it, on which is installed an electrode, made in the form of a metal tape, and a counter electrode 2.

A disadvantage of the known device is that during welding there is a sharp temperature difference between the seam zone and the surrounding leg and zone, which results in residual stresses in the material (especially in rigid and oriented materials), causing the formation of microcracks, reducing the quality of welded joints.

The purpose of the invention is to improve the quality of the welded joint.

This goal is achieved by the fact that in a device for high-frequency welding of polymeric materials containing a base (j with a fixed substrate fixed on it, on which an electrode made in the form of a metal tape and a counter electrode are mounted, the base is made with a longitudinal groove and the substrate is installed in it has a thickness of 1.01 -1.3 height

15 of the longitudinal groove, the width of the latter being equal to .1 -1.05 of the width of the substrate, and the metal tape is made wider than the width of the longitudinal groove, but not more than the width of the base.

Claims (2)

The proposed implementation of the device provides for smoothing the boundaries of the schv and the surrounding zone, eliminates the formation of residual stresses in the material, thereby improving the quality of welded joints. FIG. 1 shows the device before welding; in fig. 2 - the same at the time of welding. A device for high-frequency welding of polymeric materials comprises an upper electrode assembly comprising a base 1 with a longitudinal groove 2, in which an elastic substrate 3 is installed, an electrode made in the form of a metal tape 4, the ends of which are fixed (not shown) on the base of the longitudinal groove in a rigid base I practically corresponds to the predetermined width of the weld (the width of the welds is usually in the range from 3 to 20 mm). The ratio between the width of the groove Zpaz and the width of the substrate Zpodl. as shown by experiments, there should be Snasa (1-1.05) S With a groove width of 2 less than the width of the substrate 3, the latter is not included in the groove. therefore, good weld quality cannot be obtained. In the case where the width of the groove 2 is greater than 1.05 of the width of the substrate 3, a significant air gap occurs between the substrate 3 and the side edges of the groove 2, resulting in deformation of the metal strip 4, hence a reduction in the quality of welding. To provide the required welding pressure (1-3 kgf / cm), which in this case is created due to the deformation of the elastic substrate 3, for example, from. rubber, the latter should protrude above the surface of the base 1, and its thickness when using rubber with a modulus of elasticity of 10-100 - should be 1.01-1.3 of the height of the groove in the rigid base 1. To ensure a specified temperature distribution across the width of the seam the width of the tape 4 must be greater than the width of the groove, but not more than the width of the base 1. Welding is carried out on a metal plate 5 (counter electrode). The counter-electrode can be made in the form of a metal tape similar to the electrode of the upper electrode assembly. The device operates as follows. In the initial position, the upper electrode assembly is raised relative to the counter electrode 5. After the material 6 is laid on the counter electrode 5, the upper electrode assembly is lowered under pressure, the elastic substrate 3 is deformed, and the metallic tape 4 contacts the rigid base 1. When high frequency voltage is applied electrode - metal strip 4 And the counter-electrode - plate 5 is heated material b throughout the volume. Since the heat conductor from the surface of the material b at its contact with the tape 4, which is in contact with the elastic substrate 3, has a lower thermal conductivity than the metal base 1, is minimal, this zone has a maximum temperature corresponding to the temperature of welding - as far as from the substrate 3 heat removal from the surface of material b increases and the temperature in the joint zone gradually decreases to a temperature lower than the melting point of the polymer. The proposed device provides high strength of welded joints, reduces the likelihood of electrical breakdown. The invention of the Device for high-frequency welding of polymeric materials, containing the base with an elastic substrate fixed on it, on which the electrode is mounted. made in the form of a metal tape and a counter electrode, characterized in that. In order to improve the quality of the welded joint, the base is made with a longitudinal groove, and the substrate is installed in it and has a thickness of 1.01 -1.3 of the height of the longitudinal groove, the width of the latter being 1 -1.05 of the substrate width, and the metal tape is wide; greater than the width of the longitudinal groove, but not greater than the width of the base. Sources of information taken into account in the examination 1.Trost Nska, E. B. and others. Welding of plastics. M., “Mashinostroenie, 1967, p. 144 2.Zaitsev K. I. and others. Welding of plastics. M., “Mechanical Engineering, 1978, p. 91 (prototype). xwwwvxx to yyyyyyyxx w Р FIG. 2