Motorola Technical Bulletins
Richard Scott Torkington - Author
Motorola Inc. February 1994
English (United States)
2 pages / 105.0 KB
MO-LA Technical Developments Volumb 21 February 1994
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...