Automating design and CAM programming

Automobiles have changed substantially over the past decades, and so has the way they are built. What had once been mass produced from components to the finished product now comes with a high degree of individualization. Automobile manufacturers need production equipment capable of producing large quantities of complex parts and assemblies with sufficient flexibility for fast and frequent workpiece changeover.

A pioneer in the construction of innovative and high-quality machine tools, GROB-WERKE GmbH & Co. KG (GROB) produced its first thread milling machine in 1933. The family-owned business has since become a leading manufacturer of innovative production and automation systems mainly for the world’s leading automotive manufacturers and their suppliers. The GROB product portfolio ranges from standalone 5-axis machining centers to transfer lines for mechanical part production. It also features production systems for hybrid and electric drives, including electric motors as well as assembly lines for battery modules and fuel cells.

For project planning, design, validation and CNC program generation, GROB uses Plant Simulation, NX and Teamcenter with a bidirectional ERP integration, covering five engineering and manufacturing sites around the globe. (image courtesy of GROB)

GROB owes a large part of its success to its ability to anticipate changing market requirements and respond with innovative solutions. This strategy has been supported by early adoption of future-oriented software tools and systems to help engineers design, engineer and manufacture automotive production equipment.

GROB introduced computer-aided design (CAD) using 3D modeling for both conceptional and detailed design around 2000. The company used NX™ software to replace 2D drawings that were often still done on paper. “Our design engineers work in close collaboration throughout our production facilities in Germany, Italy, China, Brazil and the U.S.,” says Christian Lisiecki, director and head of machining systems at GROB. “Standardizing CAD using NX was a global project meant to be rolled out across the entire company.”

This early digitalization project also included product lifecycle management (PLM) software. GROB chose the Teamcenter® portfolio of PLM software for its deep NX integration and superior performance in multisite installations. Along with NX, the Teamcenter installation has been rolled out globally. “Teamcenter is the single source of truth for all GROB design engineers worldwide,” Lisiecki confirms. GROB leverages the Machine Resource Library (MRL), a Teamcenter application that provides classification and data management for manufacturing engineering resources. “Its workflow capabilities allow us to form effective project teams across our global sites,” he continues.

Although bill-of-materials (BOM) were initially exchanged between Teamcenter and the company’s enterprise resource planning (ERP) software by other, less inefficient means, information now travels between these separate systems using the Teamcenter Gateway for SAP Business Suite (T4S). “Eliminating hitherto separate data silos reduced the time required for BOM compilation by at least 80 percent,” says Lisiecki. “It also reduced the notorious mismatch errors by 95 percent.”

GROB engineers use NX CAM for CNC program generation and simulation. (image courtesy of GROB)

GROB mainly uses NX CAM for creating computer numerical control (CNC) programs. The engineers do not exchange CNC programs but 3D models between production facilities, using Teamcenter as the central information hub. These models are turned into CNC programs locally, taking into consideration the local machinery and available tools.

Many designs come with variations, differing for instance in the number and sizes of bore holes or pockets. GROB used the user-defined feature (UDF) capability in NX to create a machining rule library containing standard bore types, pockets and surface definitions, including the tools required for machining operations. This resulted in substantial savings at various stages in the product creation process. “Using NX CAM for feature-based machining helped us automate design and CNC programming work,” says Zingerle. “Recognizing 95 percent of GROB standard bore types and 70 to 80 percent of other features, the automatic feature recognition has reduced CNC programming time by 30 percent and considerably reduced the number of different tools used.”

“For us to achieve these high levels of automation and data integration took some time and required three crucial factors,” says Lisiecki. “First, the software products from the Siemens Xcelerator business platform with their long-term stability and universal interoperability; second, reliable continuous application support by Siemens, a partner familiar with our requirements, and third, in-house expertise facilitating continuous improvements with great agility.”

Martin Wagner leads the information technology (IT) group supporting technical software and converting customer part designs for use in a GROB digital twin. As an example of functionality programmed in-house that requires IT experts familiar with all the different types of software involved, Wagner explains: “Exchanging information between Teamcenter and the ERP software does more than just move BOMs across the T4S interface. The part sequence is automatically adjusted to the requirements of, for example, purchasing, after which the BOM is fed back to engineering for automatic realignment.”

GROB production workers rely on valid information from Teamcenter the JT™ data format viewers on monitors rather than paper. Using an NX open application to extract features from the NX models, GROB IT experts implemented the automatic generation of workflow routing. “They are detailed enough to differentiate between weld nuts and rivet nuts and indicate their orientation,” says Stefan Schur, Group Leader, Manufacturing Support at GROB. “NX based, automatically generated workflow routing virtually eliminated error on the shop floor.”

Another example of design automation is that any Teamcenter design release triggers the change process in the ERP software. As a practical consequence, the software is used (along with all other drawings) to create a document indicating the changes.

GROB uses NX not only to design and manufacture their equipment. When the company developed a novel additive manufacturing (AM) technology for the fast and economical production of aluminum parts, they integrated the NX all-in-one AM solution. It is linked with the machine’s slicer software that generates all information required to manufacture parts. Users of this innovative AM machines also use NX to create the supporting structures of parts. “Using Siemens software, our digital transformation now extends to include the customer experience,” Lisiecki concludes.

GROB production workers rely on valid information from Teamcenter JT viewers on monitors rather than paper. (image courtesy of GROB)