Punched, not formed

Engineers at Emuge-Franken and Audi have revolutionized a small but mighty part of automotive production with a new method for thread forming. Production time has been reduced by 75% compared with conventional technologies. 

Drilling, milling, forming – internal threads have been produced based on one of these three technologies for decades. It used to be clear to many industry experts: This is how it is and there is no way to change it. Think again. “With Punch Tap, experts at the tool manufacturer Emuge-Franken and the automotive manufacturer Audi have created a new technology – and we were able to support them with our mechatronics experts,” says Alois Penzkofer of Siemens. 


The so-called helical thread forming is a combination of punching and forming – a revolution. Compared with the other processes, the internal threads can be produced 75% faster.


Have a look at the new thread technology .

Vital impetus from Audi

“Audi initiated the development of the Punch Tap technology and provided crucial impetus,” says Penzkofer. The automotive manufacturer emphasized a clear geometry and strong retention forces for the punched internal threads. Emuge-Franken managed to produce the thread size M6, the size most used in motor blocks, in aluminum at a comparable quality using the new, patented principle.

To find out what forces occur at specific spots on the machine during punch tapping, Emuge-Franken got mechatronics experts from Siemens on board. Virtual data also supported the development of the new technology. Using a finite-element model, the engineers simulated the stresses occurring during Punch Tap on a computer. They then examined the sensitive spots in the machine and determined benchmark data based on their findings that processing centers must fulfill in order to be suitable for Punch Tap.


“At the same time, we developed a cycle that enables operators to simply integrate the helical thread forming in a CNC program, which is possible with the latest generation of controls from Siemens,” explains Penzkofer.

Huge demand

The new technology is much in demand because it provides a huge competitive advantage. That is why Audi and Emuge agreed on a retention period for companies in the automotive sector. Automotive suppliers can already use Punch Tap, but manufacturers will only be allowed to use it beginning in January 2018. Good news for all other industrial branches: They have access to the new technology immediately.