Smooth flight: Medical Manufacturing

Courtesy of All images: Brush Research Manufacturing

Heule cutting tools, along with BRM’s Flex-Hone tools, remove burrs and caps created when drilling holes in nickel, Inconel, Waspalloy, titanium and stainless steels. A precise, smooth though-hole is critical for aerospace parts.

A set of tools is used to automate drilling, reaming, deburring and edge blending of chamfered through-holes for jet-engine fasteners.

Jet-engine manufacturing typically requires through-holes that accommodate fasteners for various components and subassemblies. These through-holes must be chamfered, free of burrs and have radiused edge transitions.

“Every jet engine includes many static and rotating parts,” said Gary Brown, vice president and general manager of Heule Tool of North America Corp., Cincinnati. “Hole drilling and edge-breaking processes must be performed perfectly so that these parts stay together—particularly rotating parts. We stress making good through-holes by drilling, milling or reaming—whatever process is called for.”

Brown added that aircraft engine manufacturers demand controlled holemaking and edge-breaking processes so the parts come off their CNC machines finished and to spec. In particular, these manufacturers want to avoid costly and time-consuming bench operations, where components are deburred and finished by hand.

When cutting nickel-base and titanium alloys, drills and reamers quickly dull and can create large, extruded burrs that are difficult to remove. Burrs created from improper machining are also difficult to remove because they tend to workharden.

Combination of Tools

To avoid delays and reduce tool costs, some aerospace manufacturers are automating holemaking and finishing processes that incorporate cutting, edge-breaking and deburring tools as well as ball-style flexible hones for the edge blending process. Some jet-engine manufacturers are recommending or requiring that suppliers use these automated processes.

One such combination uses Heule’s DEFA chamfering tool, its COFA universal deburring tool and a miniature Flex-Hone tool from Brush Research Manufacturing Co. Inc. (BRM), Los Angeles.

The DEFA tool, available in sizes from 0.157 ” to 1.750 “, is a double-bladed chamfering tool that creates pre-adjusted front and back chamfers in a single pass without stopping or reversing the spindle. Using this tool, Heule reports that exact chamfer diameters can be set without trial and error.

The COFA tool blade, available in sizes from 0.157 ” to 1.614 “, cuts a smooth, tapered edge break from 0.005 ” to 0.020 “, based on the tool size. A cassette option is available for larger holes. The patented design incorporates a unique TiN- or TiAlN-coated carbide blade that allows for faster feeds and speeds and provides long tool life, according to Heule.

In combination with Heule cutting tools, a major jet engine component manufacturer applies the Flex-Hone from Brush Research Manufacturing on the machining center for final deburring of through-holes, which is usually an expensive and time-consuming manual operation.

In combination with Heule cutting tools, the BRM Flex-Hone is used for final deburring and edge blending of through-holes. “Our tool produces radiused edges on the front and back of the metal part and removes the drill burrs and drill caps created by the drill, reamer or endmill,” Brown said. “Our tools also perform the edge-breaking step, but we recommend the Flex-Hone to go in after the beveled edges have been created to round the transition between the beveled edge and the hole.”

Brown noted that drilling workpiece materials that produce long chips, such as stainless steel and titanium, can create raised material around the hole. The Flex-Hone is effective for removing such burrs up to 0.003 ” in length.