In-process vision detection of flaws and FOD by back field illumination

Abstract

A flaw and foreign object debris (FOD) detection system (11) for use during fabrication of a structure (12) includes an illumination device (13). The illumination device (13) is configured to be in proximity with a fabrication system (10) and illuminates a portion (18) of the structure (12). The illumination device (13) directs light rays (16) at acute angles relative to the portion (18). A detector (14) monitors the portion (18) and detects FOD in the portion (18) during fabrication of the structure (12) in response to the reflection of the light rays (16) off of the portion (18).

Description

TECHNICAL FIELD [0001] The present invention relates generally to the fabrication of composite structures. More particularly, the present invention relates to systems and methods of detecting flaws and foreign object debris (FOD) during the fabrication of a composite structure. BACKGROUND OF THE INVENTION [0002] Composite structures have been known in the art for many years. Although composite structures can be formed in many different manners, one advantageous technique for forming composite structures is a fiber placement or automated collation process. According to conventional automated collation techniques, one or more ribbons of composite material, known as composite strands or tows, are laid down on a substrate. The substrate may be a tool or mandrel, but more conventionally, is formed of one or more underlying layers of composite material that have been previously laid down and compacted. [0003] Conventional fiber placement processes in the formation of a part utilize a heat...

AI Technical Summary

Benefits of technology

[0011] The embodiments of the present invention provide several advantages. One such advantage is the provision of a composite structure in-process fabrication inspection technique that allows for the simultaneous detection of flaws and FOD for a single field of inspection.

[0012] Another advantage provided by an embodiment of the present invention, is the provision of a composite structure in-process fabrication inspection technique that allows for the simultaneous detection of flaws and FOD using a single illumination level.

[0013] Furthermore, the present invention simplifies the composite structure inspection process and minimizes the time involved therein.

Problems solved by technology

Unfortunately, defects can occur during the placement of the composite strips onto the underlying composite structure.

Such defects can include tow gaps, overlaps, dropped tows, puckers, and twists.

Additionally, foreign objects and debris (FOD), such as resin balls and fuzz balls, can accumulate on a surface of the composite structure.

In the meantime, the fabrication process has been disadvantageously slowed by the manual inspection process and machine downtime associated therewith.

The flaws in the composite structure are detectable within the bright field, but are indistinguishable in the dark field.

The use of dual illumination levels complicates the inspection process by causing a single field to be viewed twice, which is time consuming.

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