Add to subtract: People & Companies

It might seem counterintuitive to build up something to tear down another object, but toolmakers are using additive manufacturing technology to 3D-print cutting tools. However, the objective is not to eliminate conventional production of cutting tools but rather to print ones that would be impossible or cost-prohibitive to create another way for targeted applications.

“We don’t just print tools because we have the capability to do it,” said Ingo Grillenberger, product manager for Pittsburgh-based Kennametal Inc. “Rather, we’re strategically leveraging the unique benefits of 3D printing where it makes sense from a customer standpoint in order to solve specific challenges.”

Going Electric

One cutting tool that the company found suitable for 3D printing some of the components is the RIQ stator bore tool for finishing three diameters of an aluminum electric vehicle engine housing in one operation.

According to Kennametal, by machining three diameters in one operation, the tool ensures the alignment and concentricity of the machined surfaces while significantly reducing setup and cycle times.

This 3D-printed stator bore tool has a carbon-fiber body that weighs 7.3 kg (16.1 lbs.). Image courtesy of Kennametal Inc.” data-entity-type=”file” data-entity-uuid=”0d0d7126-c8dd-4438-a48f-89c57ac1d925″ height=”463″ src=”/wp-content/uploads/legacy/inline-images/LightestWeight-StatorBoreTool_1.jpg” width=”512″ />”Some of the features on this tool are simply not possible to manufacture with traditional manufacturing methods,” Grillenberger said.He said one specific feature is the coolant channels through the tool’s airfoil-shaped arms, enabling coolant to be applied at the exact position and angle required after flowing smoothly through corners and bends.”You cannot manufacture that in the traditional way because there are too many corners,” Grillenberger said. “You would have to drill too many angles. Here, 3D printing is a real problem-solver.”He said the tool manufacturer used finite element analysis and calculation methods to design the tool and prints it with laser powder bed melting.The latest version of the stator bore tool is about 20% lighter than the first-generation one and weighs 7.3 kg (16.1 lbs.).”We reduced weight as much as possible without compromising the tool’s performance and durability,” Grillenberger said.The lightweight, 3D-printed combination tool reportedly enables a fast tool change and rotation even on low-horsepower machines.”You can accelerate and decelerate light tools faster than heavy tools,” Grillenberger said. “It’s also more energy-efficient to speed up and slow down lighter tools than heavier ones, and machine components, such as bearings, are less stressed when running lighter tools. Part manufacturers must also account for a tool’s tilting moment in addition to its weight. If they are too heavy, the toolchanger will have difficulties to move the tool to the spindle, and the connection process will not work properly.”Last but not least, he said lightweight tools enhance worker safety.”Imagine you have a machine spindle that is difficult to reach,” Grillenberger said. “It’s much easier to bring a 7-kg (15.4-lb.) tool to that spindle than a 20-kg (44.1-lb.) tool.”Tools on a DietStar Cutter Co. in Farmington Hills, Michigan, is another cutting tool manufacturer 3D printing tools to significantly reduce their weight, said Jamie Dunneback, sales manager of round tool divisions. The company has an exclusive contract to sell tools from Ostrach, Germany-headquartered Neher Group, which Star Cutter distributes through its sister company Star SU LLC in Hoffman Estates, Illinois.Star Cutter distributes Neher 3D-printed cutting tools through the sister company Star SU. Image courtesy of Star SU

He said Neher purchased its first 3D printer in 2016 and began printing tools in 2020 on DMG Mori Lasertec 30 Dual selective laser melting machines. Nearly all of Neher’s 3D-printed tools are specials focused on large interpolating tools, such as reamers and milling cutters. Similar to Kennametal, one targeted application is machining stator housings for electric vehicles.

By 3D printing those tools for finishing large diameters, as well as other large cutters, Dunneback said Neher can reduce tool weight by up to 30%.

“It still maintains its torsional stiffness,” he said, “so the performance of the body is intact. Lightening up can be very important, especially in the aerospace business where they specify the actual max weight that a tool can be that they’re using in their process, and sometimes it is a struggle trying to get those weights.”

Dunneback said weight reduction primarily is achieved by creating a honeycomb internal lattice structure in tool bodies.

“The inner structure is where we lighten the product more than anything,” he said.

Dunneback said less tool weight means that less weight is exerted on the machine spindle, which helps with overall preventive maintenance for the spindle. In addition, when an end user has a machining center with an HSK 63 spindle interface, for example, and it should be an HSK 100 based on the weight of a conventionally manufactured tool, running a lighter 3D-printed tool can make the machine more capable.

“The worst case that we’re seeing is a tool getting dropped because of its weight,” he said, “falling out of the toolchanger because it slips from the spindle.”

In addition to being able to accurately place coolant channels of any size at any direction and anywhere they are needed in a tool body, Dunneback said additive manufacturing enables toolmakers to optimize those channels for minimal quantity lubrication applications. For both MQL and high-pressure coolant applications, consistently and correctly targeted coolant delivery can extend tool life.

“We’ve reported improvement in tool life up to 50% in some cases,” he said.

When a 3D-printed tool body becomes too worn, Dunneback said it can be reconditioned many times like any conventional body. Star Cutter reconditions tools at its facility in Farmington Hills.

“We will remove the diamond that was originally manufactured, install new diamond and finish the tool to the original condition,” he said.

Stanley X, the innovation business of Stanley Black & Decker Inc., is another company researching 3D-printed tools to optimize cooling channels, said President Michelle Bockman, who is based in Sunnyvale, California.

“Those are high-value applications that we’re trying to dig into and determine if there’s value there for our end customer,” she said.

Printing Carbide

The tool bodies that manufacturers have introduced to the market use conventionally produced inserts made of carbide and other cutting tool materials or have superhard cutting edges brazed onto them. Hyperion Materials & Technologies in Columbus, Ohio, however, developed a printable carbide powder and acquired a binder jetting system to 3D-print carbide, said Biju Varghese, vice president of the engineered solutions business and global research development.

Hyperion Materials & Technologies can 3D-print carbide rods with optimized coolant channels. Image courtesy of Hyperion Materials & Technologies

Although cutting tools, including solid-carbide cutters with special features, are part of the company’s focus in 3D printing carbide, he said other applications, such as wear parts and flow control components, are the bigger focus. The main challenge for 3D printing carbide inserts, for example, is producing them at anywhere near the speed that is achieved with conventional compacting and sintering technology.