Case Study:

TOW^® Missile Housings

Buckeye Shapeform used deep-draw technology to produce missile housings for the tube-launched, optically-tracked, wireless-guided (TOW®) weapon system.

Industry

Military & Aerospace

Product

TOW® Missile Housings

Project Summary

Some customers ask for products that are so mission-critical that failure is not an option. The liners that are used in compressed natural gas containers in buses, vans and light trucks can never fail. The aluminum liners inside a breathing apparatus used by a miner or a firefighter must always be dependable. And, so too, must the missile skins that surround a weapon that the military will use in battle.

A company that supplies equipment to the United States government for military purposes contracted with Buckeye Shapeform to use our deep-draw technology, machining capabilities and 3-D scanning technology to produce missile housings for the tube-launched, optically-tracked, wireless-guided (TOW^®) weapon system. The TOW missiles are used widely throughout the world for NATO, coalition, United Nations and peacekeeping operations.

Customer Profile

The customer, a tier-two supplier to the U.S. military, was familiar with our work. But we still had to prove our capability in order to be added to the supply chain for military parts.

Buckeye Shapeform has a long history of using deep draw technology to produce mission-critical parts that never fail. Previously we had designed and produced a skin for Hellfire missiles. Using our deep draw technology, our engineers designed a single-piece part with multiple wall thicknesses, a design far superior to the original concept because it did not require welds.

After demonstrating that the same process could be used to produce the skins for the TOW missiles, we were awarded a contract for an initial production build. The missile that these skins are being produced for, however, is forecast to be produced for years to come and is expected to be procured well into the future.

The Challenges

The challenges with this project were two-fold:

We first had to prove our capabilities to handle the project and deliver a product on time, on budget and to specifications.
Secondly, we had to develop in-depth engineering analyses to ensure that the product and its mission-critical features met the military’s tight requirements.

400 Critical Features

To overcome both of these challenges, we invested in tooling, machining capabilities and 3-D scanning technology that would ensure as precise of an outcome as possible. The skins that we produced for this client have more than 400 critical features that need to be near-exact to meet the military’s tight specifications since the mission outcome is critical.

Prior to engaging in this contract, a previous supplier had been producing this part. However, that supplier had great difficulty meeting the production specifications, holding tolerances and meeting its delivery commitments. We had been working for five years to re-establish a relationship with this customer and had positioned ourselves to take advantage of the opportunity.

Varying Wall Thicknesses with Tight Tolerances

In addition to the 400 unique features of the part, the housing also has varying wall thicknesses, ranging from three-eighths inch to four-hundredths of an inch thickness over a seamless length of 14 inches.

Many of the enclosures that we produce do not require such tight tolerances; the components being designed into the enclosure have room to accommodate the dimension of the unit. But when it comes to military applications, our engineers and technicians understand that the military components we produce are part of an assembly in which all mating parts must match up exactly. A single failure could prove fatal for a soldier, and we understand that there is no room for error in the development and manufacturing of weapons.

“Because of the critical nature of the product, meeting the customer’s demands for tight specifications is a requirement, and part of what makes this work challenging. Precision is crucial when making this part because it is only one piece of a very complex missile design and has to mate perfectly to all other components. Buckeye Shapeform’s precision manufacturing process is able to achieve geometric positional tolerances of three thousandths of an inch.”

—Carl Estock, Project Manager at Buckeye Shapeform

The Solutions

Deep Draw Technology

Buckeye Shapeform’s deep draw technology and five-axis machining with live tooling, combined with the latest 3-D scanning technology, were the perfect applications to manufacture the housings for the TOW missiles. Deep draw technology is used to create small, medium and large cylindrical shells, tubes and other shapes that require close tolerances.

Our own deep draw process, however, is a reverse draw:

Material is first pulled, or drawn, through a ring, forming a cup-shaped cylinder with uniform wall thickness.
The cylinder is simultaneously turned inside out, or reversed, combining two draws in one operation, which saves time and money.
We also iron the part during the deep draw process, which allows sections of the material to be ironed to different wall thicknesses.
Once the part is drawn or shaped, we begin the necking and expanding process to create multiple diameters in a form that more exactly matches the product engineer’s specifications. This series of drawing and ironing steps controls the flow of metal to deliver the desired configuration within the required tolerances.

Buckeye Shapeform’s deep draw technology differs from other traditional processes, such as impact or spinning. Those traditional processes cannot deliver consistent, reliable results, and they also use more raw materials, increasing the overall cost and weight of the product. Our deep draw process, however, results in a seamless, one-piece part with multiple wall thicknesses and diameters created through minimal operations.

3-D Scanning Technology

In addition, Buckeye Shapeform invested in the latest 3-D scanning technology to scan the part and verify the correct placement of all the critical features. This scanning technology allows quick quality checks to be made on a part that has hundreds of critical features. The process saves time and money because the 3-D scanner can measure the placement of the features much more quickly and accurately than if the checking were done manually.

In this step, we use a 3-D scanner to scan the part—in this case the missile skin—and then create a 3-D model that is matched up to the dimensional engineering CAD model of the original product design. Our engineers are able to look at how the two models line up to see if the part they have manufactured is matching up within the tight specifications to the original CAD model. The features that match up perfectly show in green, and those that don’t match up show up in red. Engineers can then make adjustments in the manufacturing and correct the errors in a much faster, precise fashion.

The Results

Buckeye Shapeform began delivering the first shipments of TOW missile skins in February.

Precise & Rugged – Our technology and investment in the latest 3-D scanning technology has resulted in a finished product that is precise and rugged, both qualities that are required of a product for use in the military industry.
Eliminated Weaknesses – Our deep draw technology has enabled us to produce a part that contains multiple wall thicknesses and is absent of any seams or welding, which eliminates potential weaknesses in the part.
Zero Defects – Through our investment in the latest 3-D scanning technology, we have been able to ensure that it is delivering a part that has zero defects and meets the customer’s required tight specifications.

Our team understands that precision is critical when it makes a difference in whether or not a soldier comes home safely from battle. With that in mind, Buckeye Shapeform is providing an unmatched product through our engineering expertise and meticulous attention to detail.