Tech Front: Connecting the Digital Threads
Connecting the digital data threads between machines, devices, and software that are used in integrated manufacturing was demonstrated at AeroDef 2011 Manufacturing Exposition and Conference by the Computational Manufacturing Alliance, a consortium of companies dedicated to expanding the scope of integrated manufacturing systems.
In the first of two demonstrations, the Compufacturing Alliance demonstrated how an integrated and automated assembly process called Fastener Installation Live Link Systems (FILLS) can reduce fastener installation time on aircraft parts by up to 30% using automation for data handling. The second demonstration, called In-Process Metrology (IPM), showed how an application using the Compufacturing concepts and digital-thread data flow could tightly integrate metrology and automation.
The development of FILLS was a collaborative effort between Variation Reduction Solutions Inc. (VRSI; Plymouth, MI), Right Hemisphere (San Ramon, CA), Delta Sigma (Kennesaw, GA), Northrop Grumman Corp. (El Segundo, CA), and Lockheed Martin Corp. (Bethesda, MD), under an SBIR funded by the F-35 program and administered by AFRL. According to the presenter, VRSI’s Michael Kleemann, "The original scope for FILLS was to eliminate re-work by incorporating in-process grip measurement with a dynamic bill of materials (BOM). During the course of development, the scope was enhanced with additional functionality to become a fully-integrated skin installation assistance tool."
The FILLS process was designed to overcome the limitations of traditional fastener installation on aircraft. "It generally requires paper drawings, a bin of fasteners, some masking tape, a sharpie, some sticky notes, and a lot of patience," Kleemann explains. "As production rate increases and engineering changes are made, the drawbacks to this traditional process become evident. Paper drawings and visual aids are difficult to read—there are nearly 1000 holes on just this small demonstration part [shown above]. Mechanics must measure grip length and step height, mark the results on paper or masking tape, and then install parts until tolerances are achieved."
To eliminate the non-value-added time manipulating data and performing re-work, the Alliance began by generating engineering data in the CAE environment when the product was designed. "This is the beginning of the digital thread which will connect all of the subsequent operations," explains Kleemann. "Next, Right Hemisphere Deep Access collects the engineering and joint definition data and allows manufacturing engineers to create process plans and work instruction, updating engineering changes seamlessly.
"Then, using the Right Hemisphere process plan data, Delta Sigma Assembly Works Authoring Tool allows manufacturing engineers to create projection routines for assembly and measurements tasks. These projection routines replace the paper-based drawings and visual aids with direct projection of data on the part for each task."
Preparing the structure surface before the skin is installed involves using the ProjectionWorks system to highlight the fuel-seal groove in the understructure to show where sealant should be applied. "Once the surface is prepared, upstream process data are used to predict optimum shim thicknesses based on as-built measurements of skin and structure. Shim locations and types are projected directly onto the structure and also represented at the HMI as part of a digital BOM for the as-built condition for the aircraft. Before installing the skin, a focused white light from the projection is used to illuminate cavities for the final critical check for foreign objects and debris [FOD]."
Once the skin is fit, grip lengths can be measured to update the BOM. Guided by the projected target, mechanics use the Delta Sigma wireless grip gun to measure as-built grip length. This information is collected by AssemblyWorks and used to update the fastener BOM in real time. Colored feedback at the HMI indicates when a fastener grip has changed from engineering nominal. Upstream process data can also be used, if a drilling system or other measurement system or other measurement system provides grip length measurements.
"Now that the bill of materials is updated and fastener kits are assembled, fastener installation begins. Guided by projected targets, mechanics install the fasteners either by type, or in an optimum order specified by manufacturing engineering. Any special assembly notes are called out in the Right Hemisphere work instructions. Engineering data can be presented to mechanics as nut plates color-coded by part number or by following a fastener installation sequence based on BOM, with each line item highlighted at point of task.
"Once fasteners are installed, the system prompts the operator to measure step and gap conditions using a handheld wireless laser profile sensor. Data are collected automatically and out-of-tolerance areas are flagged with projected markers. Software enables mechanics and quality personnel to mark up directly into the work instruction environment to capture process anomalies and lessons learned for the next product," Kleemann explains.
The second demonstration, called In-Process Metrology (IPM) was developed by VRSI, Faro Technologies Inc. (Lake Mary, FL), and Kuka Robotics (Clinton Township, MI) with assistance from Cenit North America Inc. (Auburn Hills, MI) and Verisurf Software Inc. (Anaheim, CA). It shows how a combination of automation, high-resolution scanning, and high-accuracy global measurement can facilitate rapid, accurate quality measurement and digital data capture. In this setup, a Kuka KR-150 robot with Faro’s AMP 3-D imager attached uses accordion fringe interferometry to scan a volume of 20 × 20 × 9" (508 × 508 × 229 mm) with resolution of 0.011" (0.28 mm) and accuracy up to 0.001" (0.03 mm). A Faro ION laser tracker is used to measure targets on the 3-D Imager, registering each scan into a single global coordinate system for a highly accurate large-volume scan. VRSI software ties together the control systems of the robot, imager, and laser tracker to synchronize data measurement and collection.
"The IPM process allows us to take advantage of a combination of automation and metrology systems. In the time it would take a laser tracker crew to manually measure a set of key characteristics on the assembly, we can automatically scan, digitize, and analyze the entire OML with accuracy of 0.002–0.003" [0.05–0.08 mm] globally. Along with FILLS, it shows how digital thread integration between systems can empower new types of automated manufacturing processes. The Alliance is preparing to take the next step in digital thread integration—defining and developing a new standard for data exchange between aerospace manufacturing systems," Kleemann concludes.
For more information on the Computational Manufacturing Alliance, go to www.compufacturing.org.
Zeroing Out Gravity
The Equipois Inc. (Los Angeles) zeroG arm allows tools, parts, and payloads to be maneuvered as if weightless, but with full range of motion. The patented zeroG arm system is designed to support a range of manufacturing, heavy industrial, bioresearch, medical, and other applications, reducing workplace injuries and associated costs from repetitive motion ailments, all while increasing productivity. In addition to supporting industrial tools including grinders, sanders, drills, nut-runners, and torque tools, applications for the zeroG arm have been extended to medical procedures, materials handling, and military field use, as well as to devices for assisting disabled individuals.
Because operators are guiding tools with the zeroG arm, rather than lifting tools, the most common causes of shoulder, arm, and back injuries—overexertion and repetitive stress—are virtually eliminated. Workers can use heavy, powerful tools for extended periods with fewer work stoppages due to fatigue, significantly reducing task times and increasing throughput. The result is that operators work with greater precision, make fewer mistakes due to fatigue, and produce higher work quality. The zeroG arm is entirely mechanical and, unlike conventional tool-support products, doesn’t require electricity, air, or hydraulics to operate.
For more information on Equipois Inc., go to www.equipoisinc.com, or phone 866-601-2070.
CNC Productivity Enhancers
Siemens Industry Inc. (Elk Grove Village, IL) has introduced solutions and services intended to enhance productivity of machine-tool end users and OEMs. Value-added services range from condition monitoring and manufacturing IT to CNC training and machine-tool retrofit, as well as the latest CNC, motor, and drive technology. The new Sinumerik 828D numerical control is designed for mid-range complex milling and turning machines in the job shop. The 828D, which combines CNC, PLC, operator panel, and axis control for six CNC measurement circuits, supports ISO programming and is capable of high-level language command. Programming time can be further reduced for small-batch production with the use of ShopMill and ShopTurn graphical workstep programming system. To reduce programming time for large-scale production, the high-level language programming can be used in conjunction with programGuide.
The Condition Monitoring value-added service is an Internet-based service that supports maintenance processes while simultaneously forming a platform for cross-company service and support between OEMs and machine operators. Services can be configured over secure Internet connections from anywhere in the world via a standard PC, and Internet connection, and a Web browser. Manufacturing IT solutions provide software tools for fast, easy integration of machines in a production network, while ensuring that production planning, scheduling, and execution are always problem-free and based on the latest available data. Software modules for production machines include production data management, numerical control program management, tool management, maintenance management, service management, and computer interfacing.
For CNC training, SinuTrain, based on the new Sinumerik Operate user interface, enables actual NC programs to be developed and simulated to speed the program generation protocol: Machine tool operators not only learn the control language commands, but also visualize part programs on a PC screen identical to the machine tool’s screen. Programs generated through SinuTrain can then be used on actual machines. SinuTrain is available in a trial version, a study version, and single-user license, and an educational license in English, Spanish, French, German, Italian, and simplified Chinese.
For more information from Siemens Industry Inc., Motion Control Business—Machine Tools, go to www.usa.siemens.com/cnc, or phone 800-879-8079.
This article was first published in the June 2011 edition of Manufacturing Engineering magazine. Click here for PDF.