547,313 active members*
2,994 visitors online*
Register for free
Login Register
Siemens - Banner
Siemens Blog

Digital Industries, Motion Control, Machine Tool Systems

Machining threads at the push of a button

June 2016
15
Author: cnc4you-ws
Company: Siemens AG, Digital Industries
 Machining threads at the push of a button

Engineers from Emuge Franken and Audi are revolutionizing the way that threads are machined. “Punch-tap” is the name of the new technology where internal M6 threads can be punched approximately 75 percent faster when compared to conventional thread-cutting techniques. As technology partner, Siemens supported the implementation of this new innovative technique using its Mechatronic Support group and generated a user-friendly cycle.

New technology Punch-tap

Punch-tap or helical thread forms – this is the name of the new technology jointly developed by Emuge Franken and Audi where internal M6 threads can be punched in aluminum at lightning speed. The market is very enthusiastic about this innovative technology, which is a combination of punching and forming. This should be of no surprise when considering that threads can be machined 75 percent faster.

This was also clearly demonstrated at the Emuge in-house exhibition at the end of 2015. At the in-house exhibition, visitors had the opportunity to watch a demonstration of the process at regular intervals during the course of the day. Many were clearly impressed, which was reflected in the high level of interest. Dietmar Hechtle, Head of the Technical Department with Emuge Franken, was very happy about this; however, he asked automotive industry customers to be patient.

Background: As Audi had initiated punch-tap technology – and had provided decisive input for its development – those responsible at Audi's head office in Ingolstadt, Germany and Emuge mutually agreed on sector exclusivity with the appropriate blocking periods. Or more precisely: Suppliers to the automotive industry can utilize punch-tap technology starting in January 2017 – and manufacturers from January 2018. Effective immediately, Emuge will offer the technology to all other industry sectors. "We are working flat out so that we can address the number of inquiries and orders that are increasing on almost a daily basis" stated a satisfied Dietmar Hechtle.

The patented principle: punch first – then form

And this is how it functions: A specially designed punch-tap tool with a twisted series of teeth arranged opposing one another is punched in a fraction of second into a predrilled hole with simultaneous helical motion. This operation creates two spiral grooves. The spindle then rotates through an additional 180 degrees while the axial feed axis is simultaneously withdrawn by half a thread pitch. And it is precisely this motion that forms the thread. The tool can then be quite simply withdrawn helically as the series of teeth are now again in the previously formed grooves. And that completes the operation. Numerous tests were carried out, and it was clearly verified that when compared to other techniques, this innovative process reduces thread machining times by 75 percent.

The geometry and holding forces of the internal threads punched in aluminum for thread size M6 – which is very frequently required – is comparable to conventionally machined threads. Engineer Hechtle stated that the helical groove form is decisive, and: "The thread depth must be at least twice that of the diameter."

A high quality machining center with a stable and high-performance spindle is also a crucial factor. This must provide a very high torque and must also be able to withstand enormous pulling and pushing loads. Emuge Franken engaged Siemens as technology partner early on in the development project to identify just which forces occur at which locations of the machine when punching threads.

Within the scope of mechatronic support, the engineers in the Technology and Application Center (TAC) were able to calculate the relevant forces using a finite element model of the production process. Based on these values, they defined the main data that the machining center must comply with in order to be suitable for the punch-tap technique.

In the meantime, several machining centers that satisfy all criteria have been investigated. If users are interested, but the planned machine has not been evaluated in the relevant detail, then Emuge urgently recommends that it should be thoroughly tested to evaluate its suitability. Both the OEM as well as SIEMENS offers this service.

Mechatronic support and cycle development

In parallel to the mechatronic support they were providing, Siemens engineers developed a cycle with which users can simply integrate the helical thread form into a CNC program. This is available as application for SINUMERIK 840D sl and SINUMERIK 828D of the latest generation V 4.7. Further, it can be subsequently integrated in the previous V4.5 version.

Machine operators and/or programming engineers can simply implement the thread punch cycle using the Sinumerik programGuide G code programming system. Once the coordinates have been defined then only a few menu-prompted keystrokes are required for the necessary twist and reversal points (drilling depth). And it's as simple as that.

 

 

 

 

0 comments

Blog Archiv

June 2021
February 2021
December 2020
July 2020
March 2020
February 2020
December 2019
September 2019
August 2019
May 2019
March 2019
January 2019
November 2018
October 2018
August 2018
May 2018
January 2018
December 2017
November 2017
September 2017
July 2017
May 2017
April 2017
January 2017
October 2016
September 2016
August 2016
July 2016
June 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
June 2015
May 2015
April 2015
February 2015
November 2014
September 2014
August 2014
July 2014
March 2014
November 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
February 2013
January 2013
December 2012
November 2012
October 2012
July 2012
November 2009