Tap Forms Internal Threads in Half a Second

Emuge’s Punch Tap enables helical thread forming in cast and wrought aluminum alloys, as well as similar lightweight materials. The short, helical tool path produces internal threads in less than half a second to reduce energy consumption and threading time.

The punch tap is made from an HSSE-PM alloy optimized for toughness and long wear. Its teeth have a geometry that produces threads in a single step. It also features two rows of flutes offset 180 degrees from each other and extending in a helical curve down to a usable application depth. This speeds threading by reducing toolpath length.         

The tool punches into a pre-drilled hole, with the first tooth of each flute producing a helical groove that guides the tap to the application depth. Threading commences by cold forming with a synchronous movement of feed and rotation. The thread is produced with a half left turn in the pitch, and each tooth produces half a thread (approximately 180 degrees). After the threads have been formed, the tool retracts from the hole in a helical motion. The finished, cold-formed thread is interrupted by two helical grooves offset by 180 degrees.

Thread strength is comparable to conventionally-machined threads from a depth of thread of 3×D, according to the company. The tool is custom-designed for coatings and dimensions according to application requirements.

The taps are used on modified CNC machines with a specialized Sync Control System and an Emuge Punch Tap software program. They are reportedly useful for blind and through-holes, and for the production of M4 through M8 metric threads with depths as low as 3×D. Featuring internal coolant supply capability, the tools are suitable for use with emulsion or minimum quantity lubrication (MQL).