RFID and Composites Automated Manufacturing Processes

November 1, 2012

Commercial aircraft are increasingly using composite materials. In fact, Airbus and Boeing expect to produce more than 8,000 aircraft through 2019, all of which will incorporate 10 times the composite material of previous models.  As the rate of composite manufacturing increases, RFID technology (radio frequency identification) is helping to drive process efficiency and product quality.  Aircraft and component manufacturers, for example, are beginning to use RFID to track composite materials and tooling through its life cycle in order to manage perishable materials and duty cycles.

Aerospace manufacturers adopted RFID technology to provide real-time location and status of physical assets in assembly and logistics operations, and to track aircraft component history in accordance with the Air Transport Association’s Part Marking Initiative – ATA Spec 2000 chapter 9.  RFID is now helping aerospace and defense manufacturers tackle specific challenges inherent in composites manufacturing, such as tracking raw materials and tooling.  These processes span a host of varied environmental conditions, from sub-zero temperature freezers (used to store composite material at 0 F) to high temperature autoclaves (used to cure composite material at over 400 F).  Composite materials can expire or degrade if not monitored carefully through extreme temperature processes such as:

    • Out-times for uncured composite material as it moves through freezers and processing areas.
    • Duty cycles of composite tooling and other indirect materials used in autoclaves.
    • Work-in-Process status as material and lay-up kits move from freezer to autoclave to finishing process.

Traditionally, tracking assets in extreme temperatures had to be managed with barcode readers and manual processes.  With the advent of ruggedized “autoclave-proof” and “freezer-proof” RFID tags that are rated for extreme temperatures and other hazardous conditions such asradiation, chemical exposure, aerospace manufacturers can now automate asset tracking from the freezer to the autoclave.

Managing Composite Materials with RFID

Composite prepreg ( commonly used for fabricating curved structural components, is a perishable material that must be transported, stored and monitored at sub-zero temperatures.  Prepreg is generally rated with a freezer out-time between 350-400 hours. Once the recommended out-time has lapsed, the structural properties of the material degrade and it must be discarded.

Tracking freezer out-time in a systematic manner is time consuming and error prone, often leading to questionable material being discarded as scrap. Since the on-hand inventory of prepreg for a manufacturer can comprise close to $1 million at any time, trimming the percentage of scrap material can result in significant cost savings.

For example, my company OATSystems and ruggedized tag manufacturer Xerafy recently worked with an aerostructures manufacturer to automate prepreg material receipt and freezer out time tracking with RFID. In this scenario, temperature-sensitive composite material was automatically tracked as it moves in and out of storage freezers and processing areas like pattern cutting and lay-up).

At material receipt, dock doors were installed with RFID readers that track incoming shipments and tag each roll of prepreg material with RFID tags as they are placed in storage freezers.  The tags are then encoded by RFID software integrated with the manufacturer’s inventory system, noting receipt date/time and batch number to start out-time tracking. Material moving from the freezers to cutting rooms and lay-up areas are tracked by RFID readers installed within the freezer doors. Directional antennas detect whether a prepreg roll is moving in or out of the freezer when the doors are opened.  Freezer out-time is automatically tracked by software and updated to the manufacturer’s materials management system. Now, plant floor staff receive an alert whenever prepreg material is approaching the out time threshold and must be used immediately. These two automated processes help manage the inventory levels and quality of the prepreg material.

The manufacturer has recognized the following benefits to date: it now has auditable time-stamped records of check-out/check-in times and assigned personal responsibility. In addition, it has reduced scrap material due to missed expiration dates and inadvertent curing. And finally, it has realized an improved utilization of high-value materials and equipment.

Given the success of this case and others, we would expect that intelligent tags and tracking solutions will find their way into other industries as well. The RFID process automation will transform the life-cycle management and overall effectiveness of business assets.

Anurag Nagpal is director of Systems Engineering and Solutions at OATSystems.

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