GB1122913A - Processes and apparatus wherein a mound of liquid is raised by vibrations - Google Patents

Abstract

1,122,913. Soldering. M.E.L. EQUIPMENT CO. Ltd. 3 Feb., 1967 [7 Feb., 1966], No. 5223/66. Heading B3R. [Also in Division H4] A mound of solder is caused to be raised in a body of liquid solder by vibrating a probe containing titanium below the surface of the body. A probe 15 comprising 11% tin, 5% zirconium and smaller amount of molybdenum, silicon and aluminium with the remainder titanium or 6% aluminium, 4% vanadium remainder titanium is coupled to the vibrating element 13 of an ultrasonic generator 14 having a winding 12 thereon connected to the secondary winding 11 of a transformer 4. The primary 3 of the transformer is connected to a current supply line 5 and to the anode 2 of an oscillator triode valve 1, the cathode 6 of which is connected to a supply line 7 and the grid 8 of which is connected to the line 7 by a grid leak resistor 10. A feedback magnetostrictive transducer forming part of the generator 14 has its winding 16 on a core 17 connected between the supply line 7 and via a capacitor 18 to the grid 8. In operation a D.C. voltage is applied to line 5 to cause the valve 1 to conduct and current to flow through primary 3 which causes current flow in the secondary 11 and thus the vibrator 13 to be energized. A feed-back potential is thus applied to the valve grid 8 to provide an automatic frequency control. The liquid solder is caused to fall with a horizontal velocity component over a lip in a curved fall and the probe is disposed radially within the fall to produce a mound over which flat printed circuits are passed. The fallen solder is pumped up to the lip again. The supply voltage to line 5 may be intermittent or alternating current as described in Specification 1,082,874.