Staying 100 per cent collision-free with VERICUT
Since 2012 the electronics group, Rohde & Schwarz, has been using NC simulation software VERICUT as the interface between programming and production at its facilities in Teisnach, Germany. Since its introduction, all program-related collisions between tool and workpiece, tool and fixture or machine components stopped completely. Errors in rapid motion and travel-limit axis movements, as well as incomplete material removal, have also been eliminated. A mid-2014 first interim report highlighted 2 years, 5 months and 27 days without a single crash caused by a defective NC program.
Rohde & Schwarz is slightly complacent about its integrated technologies with regard to smartphones, televisions, aeroplanes and cars; “Not everyone knows us, but no one can live without us,” is a typical utterance. However, Rohde & Schwarz is certainly a formidable global business with 9,800 employees and a turnover of 1.75 billion Euros in the financial year 2013/2014. The family-owned company is one of the world’s leaders in all fields of wireless communication technology.
Every mobile phone or smartphone around the globe has been developed and produced with equipment from Rohde & Schwarz; the company has installed TV transmitters in more than 80 countries, and its radio technology is used in more than 200 airports. And there’s more: Rohde & Schwarz supplies equipment and systems for radio monitoring and radiolocation in some 150 countries. With the five core business areas of measuring technology, radio and media technology, secure communications, cyber security, and wireless monitoring technology, the company addresses all possible market segments of the mobile, radio and electronics industry, through aeronautics and defence to homeland security and critical infrastructure.
Around 1,400 of the 5,900 Rohde & Schwarz employees in Germany work at its Teisnach location in the Bavarian Forest. Development, design and manufacture take place in a production area of over 62,000 m2. This ‘Centre of Excellence’ supports the manufacturing requirements of Rohde & Schwarz GmbH and, since 1991, has also accepted production work from external customers. From automotive through aerospace technology to medical technology, electromechanical assemblies, systems and custom-made devices of all kinds are produced. TV and radio stations, customised communication systems, micromechanical precision parts and circuit boards, housings, antennas and electrical charging stations complete the product range.
Given the diversity of products and manufacturing variety, there is a continuous and extensive need for development, design and programming. Ever since the introduction of the three VERICUT licences at the beginning of 2012 nearly 3,750 programmes for 3-, 4- and 5-axis milling and mill-turn machines have been written. VERICUT software is responsible for the NC code simulation of the post processed data. Konrad Früchtl, Head of the Programming Department for metal cutting production, has a clear message for the company’s 15 programmers: “VERICUT simulation is an absolute must – no NC program goes to the machine tool if it has not previously been simulated with VERICUT.”
He continues: “In total, with the retesting of some files we simulated 9,335 programs with VERICUT in two and a half years. It is true that 2,833 programmes had no collisions, but VERICUT detected collisions and more than 1,500 errors in the remaining 901 NC programs.”
Initially, the factory management asked the quite legitimate question of whether the company would actually ever need VERICUT, and how the system was to be amortized. Konrad Früchtl recalls: “The clear targets for me were the reliable production of new parts and minimal time spent proving out the programs, because until VERICUT was introduced each part, including repeated items, were running with reduced speeds and feed rates with subsequent higher costs.
“The simulation on the CAM system proved to be inadequate as it was incomplete. The reference to the machine tool’s axis end points and tool change processes was missing. Also, the comparison of the finished part to the part generated by CAM was incorrect, and the collisions on multiple set-ups were not highlighted by the software”
Noticeably since the introduction of VERICUT, the software has shown program errors exist to the same extent in 3-, 4- and 5-axis milling, while mill-turning applications proved to be particularly prone to error. With 1,500 errors detected by VERICUT the factory management realised the importance of machine simulation for collision monitoring for the protection of important production equipment. At the Teisnach factory, Rohde & Schwarz has a total of 10 Chiron and Stama 3-axis machining centres; 12 Heller 4-axis machining centres; eight 5-axis machines from Hermle and DMG, and four mill-turn centres from DMG and Index.
Around two-thirds of the program errors discovered so far have been attributed to the collision of tool and workpiece (41 per cent) and problems in machining at high speed (24 per cent). VERICUT user Thomas Schötz, a programmer at Rohde & Schwarz, adds: “In order to detect gouges, or excess material on the part, we use the AUTO-DIFF module. It automatically detects differences between the CAD model and the workpiece simulated with VERICUT.”
Given the range of components produced AUTO-DIFF provides an invaluable benefit. For example, as well as antenna adapters the Teisnach factory also manufactures micro parts by precision 5-axis milling to a design accuracy of ± 0.002 mm on the workpiece. Of course, sustainable quality work is natural part of the manufacturing philosophy at Rohde & Schwarz, as you might expect from the winner of the Bavarian Quality Award 2014. The company also holds industry-leading standards as well as highly complex certifications, such as approval as an aviation enterprise for aircraft of the German Armed Forces, the NATO AQAP-110 wireless communication technology and measurement technology and the CETECOM – Certificate of Approval, Full Quality Assurance (telecommunications and postal services) musts for the world market leader in the manufacture of mobile and EMC measuring technology and of transmitting and measuring technology for digital terrestrial television.Precision is just one side of the coin; economic production is the other. And both combine together to create an optimised solution. VERICUT, as an integral component in the transition from digital to real workpiece machining, has propelled the Teisnach factory forward significantly in this regard.