Cutting device for separating individual laminated chip assemblies from a strip thereof, method of separation and a method of making the cutting device

Cutting apparatus for use in separating one quad flat, no-lead, integrated circuit package from another by cutting through a bridging element which joins them, the apparatus comprising a plurality of abrasive wheels, each wheel comprising a disc formed of abrasive material comprising abrasive particles bonded in a matrix comprising cured polyimide resin and metal particles, the disc forming a cutting edge having a maximum thickness of the order of 350 micron, the wheels being mounted in parallel on a common shaft, whereby cuts in parallel bridging elements may be made when the shaft is rotated, and whereby the cut is substantially straight and is substantially free of smears and burrs.

A method of separating one quad flat, no-lead, integrated circuit package from another by cutting through a metal bridge elements joining adjacent packages, each package comprising a printed circuit board in a protective body therefor, the method comprising rotating an abrasive wheel to cut through a bridge element, the wheel having a cutting edge having a maximum thickness of the order of 350 micron and formed of bonded abrasive particles in a matrix comprising cured polyimide resin and metal particles, whereby the cut is substantially straight and little or no smears or burrs are formed on the cut surface.

A method of separating one quad flat, no lead, integrated circuit package from another by cutting through a metal bridge element by which one package is joined to the other, each package comprising a printed circuit body in a protective body, the method comprising rotating an abrasive wheel having a cutting edge to cut through the bridging element, the edge having a maximum thickness of the order of 350 micron and being formed of abrasive particles held in a matrix comprising cured polyimide resin and metal particles, whereby the cut is substantially straight and the cut surface is substantially free of smears and burrs.

A method of making an abrasive wheel having a cutting edge adapted to cut through a bridging element joining two integrated circuit packages and to leave a substantially straight cut substantially free of smears and burrs, the method comprising subjecting to temperature and pressure a composition comprising abrasive particles, metal particles and of a polyimide resin to cause the formation of a matrix having a high glass transition temperature containing the abrasive particles and the metal particles to weld together within the matrix, in a mould shaped to form an annulus defining a cutting edge having a maximum thickness of the order of 350 micron.