Laser Imaging Material Speeds Aircraft Parts Into Production

A simple product is having a significant impact on composites fabrication at the Boeing Phantom Works' Accelerated Digital Design and Manufacturing (ADDM) group in St. Louis. RegiStar, a trademarked laser-imageable tape from Rohm and Haas Electronic Materials (Marlborough, Mass.), was developed as a marking system for use with laser ply placement technologies. When exposed to light from "green"-type scanning lasers, the tape reproduces the laser image on its surface. The tape consists of five layers: an outer opaque cover sheet, a polyester resin sheet coated with a proprietary light-sensitive "lacquer" layer, a low-tack adhesive layer and a backing release paper. When the opaque cover is peeled back, the lacquer turns white where exposed to laser projection light. The portion of the lacquer exposed to simple ambient light darkens, enhancing the white marks. Available in 150-ft rolls in widths from 2 inches to 6 ft, the tape can be placed onto a tool as a semi-permanent registration marking aid to increase manufacturing flexibility.

According to Orval "Jack" Nobles, tool design engineer with the ADDM group, RegiStar reduced labor man/hours by 92 percent on a recent inner wing box demonstrator project. A Laser Projection Technology (LPT, Manchester, N.H.) projector already was used to indicate ply locations for part layup. Use of RegiStar tapes delivered benefits downstream, in post-cure operations. According to Nobles, the tape was applied to each part and exposed to the projector, which indicated precisely where drill holes and trim cuts were needed. This permitted parts to be removed from the layup tool and drilled and trimmed in one operation, eliminating the need to build typical "hard" tools like drilling and assembly jigs for post-processing. "The use of the tape essentially helped us to eliminate an entire set of tools, which, in addition to the time and materials needed to build them, would have required storage and extensive documentation and tracking," explains Nobles. Boeing ADDM senior manager Jeff DeGrange notes that with the imageable material, engineering data can be marked on multiple parts and passed downstream faster, which speeds the production process.

Registar tape can be re-covered with the opaque layer, to save the markings for several months. Further, in addition to outlines or hole locations, actual written instructions can be projected to help operators with processing steps or identify tools and parts, in some cases eliminating third-party documents. Nobles says that the product really pays off for low-run production, where the high cost of multiple tools is difficult to justify.