From the early 20th century through the post-World War II period, Long Island, New York, was a center of aircraft manufacturing. Builders including Grumman, Republic, Curtiss, Fairchild, and Sikorsky operated plants that turned out combat and commercial aircraft. While major manufacturers have relocated or been acquired by other companies, one job shop associated with their history combines past experience and the latest technologies to meet some of the most difficult applications for an international customer base.

Founded in 1960 as a screw machine shop, family-owned Alro Machine Co. Inc., of Lindenhurst, Long Island has evolved, now supplying parts and services for fixed- and rotary-wing aircraft. Ultimately, a strategic decision was made to concentrate on the machining and assembly of close-tolerance aerospace components and complex parts requiring hard machining, including tungsten, titanium, and high-temperature steel alloys.

Alro President Steve Young explains, “Although we’re a relatively small shop – we have just 14 people – we’ve invested in an extended capacity that enables us to machine large and small parts. Our work includes landing gear components and structural products. All our tolerances are under 0.001" and some parts require a 2µm finish. Our customers have worked with us for years and know that we can deliver. We’ve made parts for the F-35, C-130, B-1B, and 767, among many others, and we’ve invested heavily to meet our customers’ needs.”

Among the significant investments Alro has made are two high-capacity Niles- Simmons lathes with mill-turn capability. The most recent purchase is a pre-owned N30MC, a double machining head design based on two 5-axis turning-boring-milling units and equipped with a counter spindle with pick-up function. A similar machine, in use at a leading jet engine manufacturer, allows complete machining of turbine discs within two clamping operations simultaneously in a single machine. When purchased, the N30MC was equipped with a Hainbuch centroteX system. Developed for high-precision workholding of large rotational parts, the centroteX is also a quick-changeover clamping system.

Hainbuch America Corp. Northeast Regional Sales Manager Brian Eaton, says, “centroteX uses a machine adaptor plate equipped with bayonet coupling receptors that are fitted to the lathe. The plate accommodates clamping device adaptors in various sizes to easily fit into the coupling which are further strengthened by quick-tightening rapid-action screws. Alro’s system includes 100mm Spanntop collet chucks, Mando T812 ID gripping mandrels for ID work, and a 3-jaw chuck mounted to the interface plates. Changeover time is 10 minutes or less. Changeover accuracy is <0.002mm (2µm).”

Because of the sizes of the components involved, the centroteX system includes a Monteq mounting aid for larger and heavier clamping devices. An arc-shaped holder, suspended from a spring-mounted attachment, is equipped with quick-action bolts. The operator can quickly and easily secure a chuck or other clamping device for installation or removal. A specially designed roller cart provides clean, orderly, and secure storage for the clamping devices.

“When we first purchased the Niles- Simmons machine, we were unsure of how the Hainbuch system worked and why it had been installed,” Young says. “Once we learned about the quick-change capability, we were extremely happy to have it. Although large engine manufacturers might use a machine like this for long production runs, in our business, medium to short runs have become the norm, and the faster we can change over between parts, the more productive we become.”

As an example, Young cites two parts machined on the N30MC:

• 15-5PH stainless steel expansion arbor - Operations performed: milling, turning, boring; cycle time: 20 minutes to 4 hours, depending on job’s complexity
• 4340 steel chucking operation - Operations: milling, turning, boring, with similar cycle times; approximate changeover time between operations: no more than 10 minutes between chuck, collet/arbors

Eaton adds, “Steve and the team at Alro were quick to realize the potential that the Hainbuch centroteX system offers, both in terms of maintaining repeatability in hard machining operations and time savings in quick changeover. While our standard clamping devices excel in most operations, our engineering group is always ready to work with customers like Alro on the development of special customized sizes and designs for unique applications. Alro’s forward-looking attitude keeps the company ready to meet new challenges in the ever-changing aerospace industry.”

Young says, “The fascinating thing about what we do is the fact that we are at the forefront of manufacturing technologies. Methods and materials that start in aviation and aerospace find their way into other industries in time, and at Alro, we are proud to say, ‘We did it first.’”

Alro Machine Co. Inc.

Hainbuch America Corp.

Neutron imaging, a powerful nondestructive testing (NDT) method, can see through complex materials and catch flaws and defects that would otherwise go unnoticed, such as cracks and voids in energetic materials, ceramic remnants in turbine blades, and structural weaknesses in composites and 3D-printed components.

How it works

Neutron radiography (N-ray) uses a stream of neutron radiation to visualize an object’s internal structure. Similar to X-ray imaging, neutron radiation behaves differently from X-rays, producing images with new, valuable details.

X-rays can pass through light materials more easily than dense ones. The more electrons an element has, the more energy an X-ray needs to pass through it, and heavier atoms have much larger and more populated electron clouds, making them more opaque. Neutron radiation only interacts with the atomic nucleus, ignoring those sometimes dense electron clouds. Generally, it’s difficult for neutron radiation to penetrate through lighter materials because there is less space between the atomic nuclei for the radiation to pass through. Therefore, neutron radiation penetrates dense materials more easily than light materials.

There are many items used in aerospace, such as turbine blades, energetic devices, and composite materials, for which neutron imaging can provide more insight than other nondestructive testing methods.

Turbine blades

Cast from lightweight metal around ceramic cores, turbine blades have hollow air-cooling channels running through them to prevent them from breaking or melting in a jet engine’s high-temperature operating environment. In manufacturing, small amounts of ceramic can get trapped in the cooling channels, impeding airflow. Since failure of a single blade can prove disastrous for a jet engine, manufacturers trust a rigorous quality assurance (QA) process to identify any blades with this dangerous flaw.

Neutron radiation interacts in interesting ways with certain elements, such as gadolinium and boron. These elements are neutron absorbers, as their physical properties render them effectively opaque to neutron radiation. Soaking a turbine blade in a liquid gadolinium solution to tag it allows the gadolinium to settle into porous ceramic fragments but not the blade’s metal structure. So, when taking a neutron image of the tagged blade, even the smallest bits of ceramic will appear in stark contrast to their surroundings.

Neutron radiography is such a critical nondestructive testing method for turbine blade manufacturers that manufacturing output depends on the availability of neutron imaging facilities. Many neutron imaging facilities are fission reactors maintained by public universities and often have planned maintenance shutdowns coinciding with university schedules, straining supply. If neutron sources are unavailable, it impacts the entire turbine blade supply chain.

Energetic devices

Energetic devices (explosives) power the ejection mechanism in fighter planes, for example, using a series of tiny explosive charges that fire in order to blow off the plane’s canopy and eject the pilot. In rockets that send satellites into orbit, similar explosive charges in the payload fairing separation system allow release of the payload.

Energetic devices also enable explosive signal transfer systems, which are useful for high-radiation environments where traditional circuitry can damage easily. A single energetic device misfire can spell the difference between success and a messy failure. However, they are difficult to inspect for flaws with most forms of NDT, since these devices consist of a dense outer shell encasing a payload of lighter energetic material.

The energetic material within these devices tends to be a solid, hydrogen-rich chemical compound. Physical flaws, such as voids, cracks, gaps, and bubbles, can denote breakdowns in the chemical composition that can lead to misfires. Hydrogen’s high neutron cross-section makes energetic compounds more opaque to neutron radiation; unlike X-rays, then, neutron radiation can pass through the device’s dense outer shell without passing through the energetic material.

3D-printed composites

As 3D printing technology advances, additive manufacturing is quickly becoming essential for aerospace manufacturers due to its ability to construct complex designs more efficiently and with less waste than traditional subtractive methods. 3D printing technology allows aerospace manufacturers to quickly design and test prototypes of new components and composite materials.

Composites combine two or more substances in order to imbue the resulting material with the advantages of both (for example, strength from one substance and flexibility from another). However, they can be frustrating to inspect nondestructively. One component substance of the composite material may X-ray well, while another may not, making it difficult to get the full picture with just one testing method.

This is where neutron radiography complements X-rays. Applied together, both can give two halves of the whole picture. N-rays are especially useful for boron composite materials due to boron’s high neutron cross-section.

Composite materials are an especially exciting matter for aerospace manufacturers, as they can be used to create lighter, stronger, and more environmentally friendly components for aircraft and spacecraft. As composites use increases, new opportunities for NDT methods such as neutron imaging will present themselves in product testing and design, QA, and failure analysis.

Improving N-ray access

Although neutron imaging provides great NDT insight in aerospace, outside of turbine blade manufacturers, it’s not often used due to long-standing accessibility issues. Until recently, only a handful of nuclear fission research reactors could provide enough neutron output to create clear and detailed neutron images for industrial NDT. Neutron imaging has been underused for inspecting devices such as ejection and payload fairing separation mechanisms since most facilities are not equipped to handle energetic material.

However, new neutron imaging facilities are emerging with significant advantages compared to aging and dwindling reactor facilities that can provide equivalent image quality with a smaller footprint, fewer regulatory burdens, and fewer safety risks. Since its emergence as a viable industrial NDT method in the 1950s, neutron imaging has had a long history of critical use within the aerospace industry, and as newer, more accessible facilities emerge, its usefulness as a tool for research and development, quality assurance, and failure analysis will increase.

Phoenix LLC
https://phoenixwi.com

1) What does Greenleaf offer aerospace parts manufacturers?

We’ve all heard the sayings time is our most precious commodity and time is money! That couldn’t be truer than in aerospace parts manufacturing where machining hourly rates are high, the materials are exotic and difficult-to-machine, and the quality requirements are strict. This creates a tremendous opportunity to add value through great, high-performance tooling solutions, technical applications support, and outstanding customer service. Greenleaf is the world leader in high-performance ceramic tooling and technical ceramics, so we know the ins and outs of saving time and money.

2) What performance advantages are possible?

We like to keep things simple for our customers. When ceramics are applicable, we will make a commitment to do the same job in much less time, equaling more profit for our customers. In most cases, we can reduce overall machining time by 6x to 10x, a value proposition that’s tough to beat. Getting more parts across the machine and out the door faster will free up machining time to manufacture other products or take on more volume.

3) What are the right applications for ceramics?

Ceramic tooling is applicable to a broad range of workpiece materials including nickel- and cobalt-based alloys, hardened materials, select stainless steels, cast and ductile irons, and materials with heavy interruptions and scale. Once the workpiece material is deemed a good fit for ceramics, we need to be sure the machine has a good, solid spindle capable of the required speeds. You also need good fixturing for the workpiece to avoid vibration and harmonics, which are detrimental to ceramic machining.

4) How do you know when to choose ceramic, carbide, or CBN?

As we’ve seen advancement in ceramic material science, we are expanding the field of operation where ceramics can be applied. We’ve successfully machined medium carbon steels with XSYTIN^®-1, our newest ceramic, at 1,600sfm compared to 1,000sfm with carbide. XSYTIN^®-1 also works well in heavy, interrupted cuts and cutting through the nasty scale of forgings or heat-treated materials.

I continue to be amazed at what XSYTIN^®-1 will cut. Every day we find opportunities to convert customers to ceramics. When hard turning shafts with ceramics, we successfully replace CBN inserts and offer greater value.

5) What sets Greenleaf apart from other cutting tool manufacturers?

Greenleaf prides itself on running toward opportunities that others walk away from. Our custom-engineered tooling solutions offer unique features and capabilities that allow customers to process their parts in the most efficient manner possible. We start by looking at the entire process and understanding what the customer wants to achieve. Once we know the goal, we assess the machine, fixture, part, material, and coolant needs to make sure we develop the best custom-engineered solution available. Greenleaf has more than 150 years of design engineering expertise, and we have developed more than 125,000 unique custom tooling solutions for our customers.

Custom steel and insert tooling is a core part of what we do for our customers. When you wrap innovative technology, custom engineering, superior customer service, and on-time delivery into one package, customers keep coming back for more. We like that!

For more info: http://www.greenleafcorporation.com