Louis Thomas Manzione

Low cost molded packaging for optical data links

In order to lower the cost of optical data link packaging, a new technology has been developed which integrates optical and electrical components in a single, sealed, transfer molded package. This technology utilizes leadframes for low cost and mass handling. Overmolding is used for package sealing and optical port alignment. A unique process, two-step transfer molding, allows for internal shielding, intermediate IC testing, ease of assembly, and IC package sealing. An injection-molded outer housing is used for connector insertion and external shielding (through the use of conductive plastics). The first application of this technology is a high performance optical transceiver package for the growing FDDI market (125 Mb/s). With a duplex MIC connector, this package conforms to an industry standard outline and pinout. The optical transceiver easily meets full FDDI specifications. The design integrates an LED, PIN, transmitter IC, receiver IC, and two capacitors in a single, overmolded package. The final assembly sequence was conceived using the latest Design For Simplicity (DFS) principles. This paper describes the design concept and prototype model performance results. >

Simulation of Cavity Filling and Curing in Reaction Injection Molding

Reaction injection molding1 is polymerization and processing in a single cyclic operation. It consists of several distinct processes. Reservoirs of one, two, or more components are metered according to a pre-determined ratio and then conveyed under pressure to a mixing head. The fluids are either mixing activated in the head or thermally activated upon injection into the mold cavity. Considerable viscosity increase can occur during cavity filling, the extent depending on the fill time and resin reactivity. Most of the chemical conversion usually occurs during the mold curing step after the mold has been filled. The part is ejected after some fixed mold residence time which allows the part to attain dimensional stability. The cycle time includes the time for cavity filling, mold curing, and mold preparation and it is often desirable for it to be a minimum. Excessive cycle times due to long cure times may eliminate or limit the use of a molding resin in a particular application.