1) How have wire EDM machines evolved and how has the technology improved?

Traditionally, many manufacturers viewed EDM as a niche industry. For decades, machinists considered EDM a necessary evil. With cutting speeds much slower than milling or turning machines, around 2 square inches per hour, nobody was using an EDM machine except for cutting steel or aluminum.

Modern wire EDM machines have made vast technological improvements. Cutting speeds exceed 32 square inches per hour, and with core stitch and automatic wire feeding, EDM machines can go head-to-head with mills and lathes in specific applications.

Wire EDM machines are getting even better at what they were designed to do – removing precise amounts of material with surgical precision.

2) What are the benefits of using a wire EDM machine in aerospace component manufacturing?

EDM machines can cut through various tough metals, from high-strength nickel alloys to titanium. Moreover, they can machine intricate paths with virtually zero recast layers. These two attributes make them perfect for any aerospace manufacturer.

FANUC wire EDM machines are ideal for cutting complex shapes or patterns commonly required in aerospace manufacturing, and they’re versatile. Since the wire and the workpiece don’t make physical contact, it’s easy to transition from machining tough-to-cut metals to delicate composites.

3) How can wire EDM machining effectively manufacture components for the aerospace industry?

The advent of AC power supplies changed how wire EDM machines operate and what materials they could cut. These newer FANUC power supplies reduce or eliminate metal deformations and the part’s heat-affected zone, making it a practical choice for aerospace manufacturing. By cutting with AC, heat is reduced and transferred away from the workpiece.

4) How can someone get the most out of their wire EDM machine?

No two operations are exactly alike. It’s essential to work with your machine tool supplier to determine which system best fits your shop. Having those in-depth discussions and exploring your machining opportunities is a critical step of any manufacturing process, laying the foundation for your organization. Shop owners must discuss some details with their supplier: wire diameter, part tolerances, machine options, floor space, part size, etc.

Once you have a good idea of what machine will work for you, consider automation as a next step – a host of standard and custom automation cells can maximize throughput. It’s the most straightforward way to get the most out of your machine. Whether you’re looking to decrease cycle time or run your wire EDM machine lights-out during off-hours, automation can open a world of opportunities.

5) What are some ways to reduce long cycle times commonly associated with wire EDM machining?

The best ways to improve cycle times are larger wire diameters, specialty coated wires, and occasionally stacking parts to produce more parts per cycle. By using a larger wire, more current can be applied for faster cutting. When you pair a large diameter wire with a coated wire, you can further increase cycle time. There are many types of coated wires, ranging from zinc to gamma-phase designed to pull cutting process heat away from the wire’s core, helping eliminate wire breaks.

For more information: https://www.methodsmachine.com

Simulation technologies, such as computer-aided design (CAD) or finite element analysis (FEA), allow aerospace engineers to visualize complex part geometries, understand how parts respond to applied loads (structural analysis), and optimize tooling resources. Digital twins allow machine- asset monitoring and supply chain management. These technologies reduce costs by pulling critical product decisions further upstream where processes and simulations are less expensive than physical prototyping and testing physical prototyping and testing.

Similar benefits extend to testing, where technology increases the efficiency of quality assurance processes. Real-time data acquisition and processing, digital repositories for customer specifications, and collaborative workflow tools accelerate product rollouts.

Virtual testing – using computational modeling and simulation to improve designs and material properties – exposes a design to real-world loading and material properties to identify undesirable results before they happen. Virtual testing also optimizes maintenance, improving sustainment costs and reducing warranty risk – results American Airlines discovered firsthand.

Case study

In 2007, the Federal Aviation Administration (FAA) mandated American Airlines to cold start auxiliary power units (APUs) for each of its Boeing 777 aircraft once per quarter. Increased testing led to three to four APU removals each year, which were expensive, left aircraft out of service, and produced an unpleasant cabin odor upon failure. Bearing failures were to blame, but American Airlines couldn’t pinpoint the source of the problem: Was it the material, design, lubricant, or operating protocol?

To find the answer, materials engineering software company Vextec performed virtual tests analyzing a new APU bearing as well as a bearing broken by operating. The team also evaluated general operating condition notes provided by American Airlines. Vextec’s simulations studied sensitivities related to normal versus cold start, load and design, and lubrication. The studies showed the bearing design was appropriate, but the way the cold starts were performed caused the failures – and the lubrication needed to be changed.

After receiving FAA approval of this solution, American Airlines introduced new lubricant and cold start protocols in August 2011. Since then, the carrier has experienced no APU failures and saved up to $4 million annually. That improvement came while avoiding exorbitant physical testing costs and time commitments for bearings. Plus, American Airlines didn’t have to redesign the bearing, which simulation testing showed would lead to more failures.

Industry 4.0 and AM

Virtual testing is one of many technologies transforming aerospace manufacturing as part of Industry 4.0. Additive manufacturing (AM) plays a bigger role in that transformation by presenting a fundamentally different way to build aircraft.

As AM becomes more capable in production of flight-critical metallic parts, it will impact original equipment manufacturers (OEMs) and maintenance, repair, and overhaul (MRO) operators. Better control of production volume and just-in-time manufacturing should lower costs for OEMs. Producing replacement legacy parts that would otherwise be difficult to source will be a key revenue generator for MRO.

Closely tied to making AM able to produce critical parts is effectively certifying AM-built parts for use. Since AM processes have shown to be more variable than conventional processes such as casting and forging, typical quality assurance/quality control sampling techniques (for example, testing only a small number of produced parts) are difficult to implement. Virtual testing using a computational simulation of product performance can increase confidence in AM for critical uses without the need to test each AM-built part – similar to what American Airlines did with its APU bearing.

Implementing technology

Steps to technology adoption include:

Optimize product lifecycle management (PLM). PLM extends from early design phases through user performance. Technologies that can address multiple areas of PLM at once – such as simulation software – optimize PLM with the largest repository of data possible to create a feedback loop throughout the life cycle.

Leverage third parties. Software subscriptions often include technical and product support, adding value when integrating the technology into an established PLM workflow. Subscriptions are also more affordable and flexible than purchasing software outright.

Think holistically. AM, known mostly for rapid prototyping, can handle production in some instances. Explore how new technologies fit holistically into the PLM to identify areas it can (or can’t) apply.

Aerospace manufacturers must see technology for what it truly is: the future of the industry. For all the advancements and improvements made in recent decades, they pale in comparison to what will be possible, and, in many cases, what’s already possible for those who embrace the opportunities.

Vextec Corp.

About the author: Dr. Robert Tryon is the co-founder and CTO of Vextec, a software and engineering services company specializing in predictive analytics, prognostics, and life extension for automotive, aerospace, industrial, and medical device products. He can be reached at rtryon@vextec.com or 615.372.0299.

Original equipment manufacturer (OEM) performance targets for aluminum demand higher production speeds and lower costs. A manufacturing method promises to produce complex, high-strength aluminum pressings, potentially reducing material use and the mass of conventionally pressed aluminum structures.

Impression Technologies Ltd. (ITL) was formed in 2012 to bring to market the hot form quench (HFQ®) process developed within Imperial College, London, UK (see Figure 1). The process heats a shaped aluminum blank to its solutionizing temperature (500°C to 550°C) before pressing and rapidly cooling the workpiece while still in the tool. The now-formed part can be subjected to further treatment, ensuring the material reaches its full strength.

The technique

Aluminum HFQ structural components could reduce weight up to 20% compared with lower strength, cold-formed aluminum counterparts. In addition, the material’s increased formability at HFQ temperatures means parts can be deep drawn in a single operation, reducing the need for reinforcements. Removing the requirement for secondary forming operations also reduces tooling costs.

The essential features of the technique, says ITL’s Director of Innovations Dr. Alistair Foster, are that “it combines mechanical and heat treatment into a single forming operation.”

He explains this is achieved by raising the material’s temperature until it reaches the relevant solution heat treatment level. At that point, the alloying elements form a solution within the material and stay in solution after the in-tool quenching process initially provides a “W temper that will naturally age to a T4 condition, which can be artificially aged to an alternative temper, such as T6 condition” – the latter being the strongest possible state for the material.

The blank is held in situ to allow quenching of the formed part. Quenching the part in this way combined with optimized age hardening stabilizes the aluminum’s microstructure, delivering strength, formability, and productivity.

HFQ virtually eliminates springback – also known as elastic recovery – compared with cold-forming aluminum. John Sellors, director – applications engineering at ITL, says this has important implications for dimensional control during assembly operations and is something of interest to OEMs.

“With cold-formed, high-strength aluminum especially, springback can be a problem, but with HFQ, it’s reduced to nearly zero,” he states.

Innovation

Recently, ITL management announced the company’s collaboration in the Future Advanced Nacelle Technologies and Structural Integration Concepts (FANTASTIC) project led by Bombardier and supported by the UK Aerospace R&T program, a partnership between Aerospace Technology Institute (ATI) for Business, Energy, and Industrial Strategy (BEIS) and Innovate UK. The FANTASTIC project seeks to enable design and delivery of high-strength, high-accuracy, lightweight HFQ-formed components in aerospace-approved aluminum at lower cost than existing processes.

In a separate development, aluminum rolling and recycling company Novelis Inc. has agreed to partner with ITL to explore innovative ways to increase adoption of aluminum through the hot-forming process.

Currently, ITL has inquiries from several aerospace companies for applications such as seat components, wing ribs, wing flaps, engine inlet lip skins, and leading-edge slats.

Any shape or form

HFQ technology can solve many forming and assembly problems caused by cold forming and superplastic forming techniques. ITL offers aerospace component suppliers the opportunity to install HFQ manufacturing technology within their organizations by becoming a licensee, which gives access to support services to assist in designing and manufacturing HFQ technology components.

These services include:

• Design & simulation – ITL team assists companies to maximize cost-effective mass reduction of complex, high-strength HFQ aluminum panels
• Development – ITL team reduces the number of press tools required to produce a part, significantly lowering the required investment
• Prototyping – ITL’s facility carries out in-house production runs, supports HFQ technology customers
• Tooling – In-house prototype, production tooling try-out facility, with assistance from expert know-how team
• Training – Customized training courses covering each aspect of the product life cycle

ITL plans to continually develop HFQ technology to ensure the benefits of the technology are maximized for future use.

Impression Technologies Ltd.