ICEBOX PACKAGE

MO-LA Technical Developments Volumb 21 February 1994

ICEBOX PACKAGE

by Richard Scott Torkington

  Physical compartmentalization of electronic cir- cuitry prevents signal cross-talk and satisfies other EMI/isolation requirements. Relatively thick, custom- machined plates (often aluminum or alloys thereof) are usefully employed therefor when small quanti- ties (e.g., < 100 pieces) are needed and when the costs of this approach (ca. $500-3,000) are acceptable.

  Generic packaging elements which are easily modified for specific applications reduce costs while providing custom compartmentalized electronics packaging. An injection-molded conductive (metal, conductive or conductively-plated polymer) wall-web structure comprising partitions forming regular prisms (cubes are illustrated) is depicted in Figure
1. Modification for specific requirements is realiza- ble via subtractive methods, i.e., machining.

  Figure 2A illustrates removal of unwanted walls while Figure 2B depicts the result ofweb removal to provide a through-frame. Figure 2C shows added holes for connector mounting etc., while Figure 2D

provides an isometric view of a "re-outlined" pack- age. The operations providing the results illustrated in Figures 2A-D all involve relatively inexpensive machining operations such as low tolerance mill- ing, flycutting, drilling etc. When fashioned from non-conductive materials, a conductive plating step desirably follows the machining operations.

  A variety of distinct finish...