Entry sheet for drilling holes in printed circuit boards

摘要

An entry sheet comprising polymer material for drilling printed circuit boards is provided. The entry sheet is suitable for use with a broad range of diameters, including commonly available drill diameters. The entry sheet comprises an adhesive epoxy configured to, among others, resist drill deflection, resist mechanical damage, and reduce to dust such that the entry sheet may increase drilling accuracy, protect printed circuit board from damage, minimize entry burrs, and may addresses other issues such as fliers, bird nesting, and the like.

主权项

1. An entry sheet for drilling circuit boards, the entry sheet comprising:
a planar, sheeted substrate layer having a thickness of about 6 mils or less and configured to be positioned over at least one printed circuit board which is to be drilled; and an entry sheet component coated on the substrate layer, wherein the entry sheet component has a thickness of about 6 mils or less, and the entry sheet component comprising a coating coated on the substrate layer such that a drilling tool passes through the coating during drilling of the circuit boards, the coating comprising:
a salt, anda fully cured, completely hardened thermoset adhesive, the adhesive selected from the group consisting of an epoxy, an acrylic, a polyimide, a butyral phenolic, and a combination thereof; wherein the substrate layer comprises at least one layer of aluminum.