Gantry mounted ultrasonic wire bonder with orbital bonding tool head

Abstract

An automatic ultrasonic wire bonding machine for bonding interconnecting wires to electrically conductive sites on a workpiece includes a gantry which supports a generally downwardly cascaded series of support platforms linearly translatable with respect to the gantry and to one another in response to translation drive signals provided from a remote source to a separate translation motor for each platform. A head support assembly mounted to the last translatable platform in the series rotatably supports via a hollow elongated spindle an orbital bonding tool head rotatable with respect to the head support assembly in response to a rotational drive signals provided to a head rotation motor from a remote source. The orbital bonding tool head in turn supports via a novel parallelogram linkage an ultrasonic transducer having fitted therein a downwardly protruding ultrasonic bonding tool, the parallelogram linkage enabling the tool tip to be displaced only vertically in response to reaction forces exerted on the tip in translating the tip downwardly into contact with a workpiece. Attached to a transducer support block comprising one element of the parallelogram linkage is a wire clamp located rearward of the bonding tool which has a pair of laterally opposed, laterally reciprocally actuable blades which move apart to receive and allow free movement therebetween wire from a wire supply reel, and together to grip the wire, and a clamp actuator for reciprocally moving the clamp blades in unison towards and away from the bonding tool to thereby feed wire through a wire feed bore disposed diagonally through the tool. The clamp actuator includes a hollow drive shaft which is disposed vertically and axially through a bore provided through the head drive spindle, the drive shaft having pinned to its upper end a belt-driven pulley and pinned to its lower end an eccentrically mounted cam wheel on which rides a cam follower protruding from a bell crank pivotably coupled to a parallelogram linkage bar and rigidly coupled to a clamp blade support. Wire from a supply reel located above the head courses through a bore disposed axially through the clamp actuator drive shaft, exiting through a central coaxial bore through the cam wheel, and through a vertically disposed bore through the transducer into a diagonally disposed channel formed between the jaw blades. Preferably, the machine includes a drag tube for frictionally resisting motion wire supplied from the wire supply interposed between the exit opening in the bottom of the cam wheel, and the clamp blades, the drag tube having a vertically disposed straight lower portion which fits in a bore vertically disposed through the transducer, an arcuately curved intermediate portion connected to an upper end of the vertical portion, and a straight upper portion connected to an upper end of the intermediate portion, which is angled upwardly and forwardly towards the cam wheel at an elevation angle of about sixty degrees.

Dependencies are inferred from the claim text.