The Boeing Company

Jim S Piszar

Neal A Froeschner

Jeffrey J Kilwin

Christopher B Mathiesen

An adhesive injection process for a Pi-joint assembly comprises the steps of: machining at least two ports into a female part of a Pi-joint assembly; inserting a filler into a gap between a male part and the female part; applying a sealant above the filler; creating a vacuum with a vacuum pump at one port; injecting an adhesive through another port; and drawing the adhesive towards the vacuum pump until the gap under the filler is completely filled with the adhesive. The adhesive injection process incorporates lean technologies that enable increased productivity during the assembly of a Pi-joint design using adhesive bonding. The adhesive injection process is suitable for, but not limited to, applications in the aerospace industry, such as the aircraft airframe assembly. The adhesive injection process may be used for the bonding of upper and lower skins to airframe structure as well as for structure-to-structure bonding.

Adhesive injection process for Pi-joint assemblies

A tool for trimming the ends of stiffeners on aircraft composite skin panels accurately, rapidly and without damaging the underlying skins includes an expandable guide frame adapted to straddle and clamp to the stiffener at a selected longitudinal position thereon. The frame includes a pair of planar guide faces disposed on opposite sides of the stiffener and lying in a common plane transverse thereto. The rotatably supported opposite ends of a rotating abrasive drum are slid along respective ones of the guide faces such that the drum grinds away the stiffener in a plane parallel to the plane of the guide faces and thereby forms a trimmed end on the stiffener. The frame includes mechanisms for adjusting the angular inclination of the plane of the guide faces relative to the plane of the composite skin, and for preventing the grinding mechanism from cutting into the composite skin.

Trimming composite skin stiffener ends

A tool used to direct the pressure applied to features of a plastic laminate part layup during co-curing or co-bonding is manufactured using direct digital manufacturing techniques. A CAD drawing representing the tool is generated and converted into digital data file suitable for controlling the operation of a rapid prototyping machine. The tool is formed in the rapid prototyping machine by additive layering of material until the features and dimensions of the layered material correspond to the CAD drawing. The resulting tool exhibits geometries and dimensions virtually identical to the theoretical dimensions of the CAD model of the tool.

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Chesterfield, MO, United States of America

Jim S Piszar