Structural members, such as composite structures used in the aerospace industry, are often joined together by drilling holes through the structural members and fastening the members together with bolts or other such fastening devices. To ensure proper drilling of holes and an appropriate fit, it is generally desired to have as tight an interface between the structural members as possible. However, due to part size, shape, and tolerances, voids or gaps often exist between such structural members.
A liquid shim can be used to reduce or eliminate a void or gap between such structural members so that holes can be drilled with precision and when bolts are applied, the interface between the structural members is tight. Liquid shim is typically a viscous, sticky resin. Examples of common liquid shims include epoxy resin material with a high compressive strength. When voids or gaps are found between two structural members, the liquid shim is applied between the structural members in an amount sufficient to fill the void or gap, and given time to cure to a hardened material. The liquid shim may be cured either at room temperature or at elevated temperatures. The application of heat greatly speeds up the curing process. Holes are subsequently drilled through the structural members and the liquid shim to permit the fastening devices to be applied.
Current methods of drilling holes in structural members when utilizing liquid shim typically require a large amount of time, a large number of steps and number of tools, and a large amount of manpower to apply and remove the tools. For example, in typical methods the liquid shim is first applied between the structural members and a special curing tool is applied to the structural members to cure the liquid shim. The curing tools then need to be removed before the drilling process begins. Once removed, drilling tools such as a drill jig may be applied to drill the holes through the structural members and the liquid shim Thus, current methods of drilling holes when utilizing liquid shim are inefficient.