CompositesWorld
Issue link: https://cw.epubxp.com/i/919214
TRENDS JANUARY 2018 22 CompositesWorld Despite the availability of fast, efficient automated fiber placement (AFP) and automated tape laying (ATL) machinery and AFP/ATL-compatible composite materials, commercial aircraft production has often not been very fast and efficient because mandated inspection of parts is still a production bottleneck. Careful visual inspection and verification is needed after each ply, by trained human inspectors, to meet quality assurance requirements. For a large composite part, such as a fuselage barrel requiring hundreds of plies, the negative impact of inspection (and any rework) on automated process efficiency is significant, according to information presented at recent industry gath- erings. For example, in a paper presented several years ago by Robert Harper of Fives Cincinnati (Hebron, KY, US) and Allen Halbritter of The Boeing Co. (Chicago, IL, US), based on a generic fuselage barrel and using an optimized AFP process, inspection and rework still made up more than 60% of the total part production time. David Maass of Flightware (Guilford, CT US) puts it in more stark terms: "We've got to get rid of an 18 th Century methodology being used for a 21 st Century part." Fortunately, that situation is changing, for two reasons. First, increasing percentages of newer aircraft are made from composites and, second, resulting pressure for higher production rates is driving development of new technolo- gies for automated, in-process inspection — taking inspec- tion out of the hands of humans and performing inspection as the part is being fabricated. Groups around the world are working on the necessary technology development and taking great strides toward the goal of making inspection as fast as the production process. CW is in the process of gathering information about these new automated inspection processes, and plans to publish a series of articles in print (in CompositesWorld magazine) to bring these technologies to light. "It's been said that automated inspection is 'low-hanging fruit' and the easiest way to really reduce aerospace AFP part production time," says Maass. His Real Time Automated Ply Inspection (RTAPI) system is one example. It consists of a laser profilometer, available commercially, off the shelf. This very powerful but very low-cost sensor, contains a laser line generator and a camera. The sensor collects measurements of height and width points (about 1,000 points for every tow course) and delivers point cloud data to a software program and user interface that Maass has developed, which converts the data into layup features of interest, such as tow edges, tape ends (adds and drops), gaps, overlaps, etc. Maass' system mounts the profilometer directly on the layup head, from where it measures the heights of the fiber tows following the compaction roller, generating "millions of data points for each course in a very dense point cloud," states Maass, adding that the data-processing step of the RTAPI technology is patented. In early work, the system was capable of detecting all features of a single course in fewer than 10 seconds, but in recent work that time is being reduced to near real-time operation. The software compares the as-made layup against the automated machine's part design program to identify gaps, overlaps, dislocated plies, late adds, perform foreign object detection (FOD) and more, explains Maass. Flightware worked with CGTech (Irvine, CA, US) to adapt the latter's VCP AFP programming software to read and display layup flaws automatically detected by the RTAPI system. Flaw types are shown using symbology and color codes, so the operator knows where to look and what to look for. The system was designed to accept and allow operator-selected QA criteria. The API (Automated Ply Inspection) technology was devel- oped in 2014 under a NASA-funded program. Then the US Department of Defense's Defense Logistics Agency funded work to enable "real-time" operation (hence the acronym, RTAPI). The current program includes funding to demon- strate the system on actual, complex aerospace parts. Watch a YouTube video produced by Maass, which shows how the software works to identify problem tows | https://www.youtube.com/watch?v=_2KuzbHe4eU&feature;=youtu.be CW's Automated Inspection Series preview: Real-time automated ply inspection (RTAPI) system AEROSPACE Source | Flightware