SAMPE Journal - January/February 2012 - (Page 6)

Feature Article In-Process Fiber Orientation Measurement and Foreign Object Damage (FOD) Prevention for Complex Preform or Prepreg Lay-ups K. Hazra, University of Bristol, UK S. Blake, Assembly Guidance Systems, Inc., Chelmsford, MA USA K. Potter and M. Wisnom, University of Bristol, UK Email: Abstract Process control in both automated and manual production of composites structures is essential to ensure that the “as-built” part is an accurate realization of the characteristics chosen by the part designer. Manufacturing variations from the nominal design can result in compromised part performance or even structural failure. The lack of efficient, near-real-time, quantitative reporting of part characteristics during part fabrication results in an uncertainty requiring overdesign, with corresponding extra material and weight. An in-process vision system that compares design model and as-built characteristics has been operated on a complex preform as well as hand laid prepreg material. The system and its operation are described along with results achieved in initial applications. Background As new manufacturing processes and materials enter production, there is a requirement for verification and documentation that these new processes have been carried out as designed. Currently, high demand in composites fabrication is driving many new manufacturing processes. Development of verification and documentation systems for these new processes has not kept pace with the new manufacturing processes. Process control is principally carried out by human inspectors. While humans are flexible and mobile, they are subjective, and prone to distraction and error. People are not able to make rapid, accurate measurements or evaluations. The robustness of quality processes using visual inspection by the lay-up operator or QA specialist are reliant on their continuous skill and integrity. Robust methods of verifying and documenting correct fabrication must be available in order for new processes to gain long term acceptance1. A fully integrated, automated inspection system would, therefore, take out the human element and identify conformity and discrepancies in real time. Also, the information gathered through an automated vision system can be linked to the final NDT results to produce an effective non-conformance database; supporting improvements in process control and quality. Approach The effort documented in this article involves operating a laser projector that has been enhanced so as to provide a calibrated, machine-vision function. This system is called “ProjectorVision” (See Figure 1). The hardware and much of the software are mature products already in use in fabricating 6 hand laid prepreg parts. The process monitoring functions were developed and operated on a curved preform and a complex surface supporting hand lay-up of prepreg. Fiber orientation measurement, verification and documentation functions were run on the preform and the hand lay-up tool surface. In-process FOD (Foreign Objects/Debris) detection functions, identifying FOD on part surfaces about to be covered by a new layer of material, were run on both parts. Manufacturing data, similar to that which is in common use today, was used to drive the process-monitoring functions. The system was operated under a variety of lighting, data, FOD, and fiber orientation conditions. Examples of operational results from these varied process conditions are shown. The ProjectorVision System A laser projector is an optical aiming system driven by design data, that scans a dot of laser light along a path, where features, defined in a CAD model, should occur. The brightness of the laser dot, being scanned by the optical aiming Figure 1. ProjectorVision LASERGUIDE System. SAMPE Journal, Volume 48, No. 1, January/February 2012

Table of Contents for the Digital Edition of SAMPE Journal - January/February 2012

SAMPE Journal - January/February 2012
President’s Message
Technical Director’s Corner
In-Process Fiber Orientation Measurement and Foreign Object Damage (FOD) Prevention for Complex Preform or Prepreg Lay-ups
The World of the Future: What is SAMPE’s Material Contribution?
Corporate Partners
Europe News & Views
SAMPE Europe’s SEICO 2012, Paris
SAMPE Tech 2012 Call for Papers
SAMPE Books & CD’s Order Form
SAMPE Proceedings
New Processes for Large Scale Automotive Production of Composite Applications
The SAMPE Foundation
Materials & Products
SAMPE LinkedIn Communities
SAMPE Journal Editorial Calender
Welcome SAMPE’s Newest Members
SAMPE 2012|Baltimore
SAMPE 2012 Exhibition
Industry News
SAMPE Asia 2012|Kuala Lumpur, Malaysia
SAMPE Tech 2011 Ft. Worth Review
Upcoming SAMPE Events
12th Japan International SAMPE Symposium and Exhibition – JISSE-12
SAMPE China Review
Advertiser’s Index
Resource Center
Membership Application
Industry Events Calendar
Chapter Meetings Dates and Contacts

SAMPE Journal - January/February 2012