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At last, manufacturing interconnects with design and engineering.
Design engineers have been sharing data for years with Step (Standard for Product Data Exchange), which became an ISO standard in 1994. Now, that same data has made its way to the shop floor and is running machine tools.
Basically, the standard is the smooth and seamless exchange of part information between CAD, CAM, and NC programming. While the standard is now in use at companies worldwide, it typically encompasses just the sharing of CAD geometry. But thanks to two recent initiatives, one in Europe and one in the U.S., the chain is complete, and the Step standard is spreading to NC programming in the form of Step-NC. It supports the feature-based link of the CAD world within the CAM/NC world.
Currently, a Step-NC prototype is being tested at the DaimlerChrysler plant in Stuttgart, Germany, and involves the cooperation of a number of industrial companies, information-technology vendors, and universities. DaimlerChrysler is providing the machine and performing user tests, Siemens is responsible for the controller, and software vendors (Dassault Systemes and OpenMind) handle the CAD/CAM integration.
The focus of the testing is prismatic milling and drilling applications. After the first exchange of data for 2.5D milling, the test will expand to cover 3D milling. The NC machine tool, a 5-axis Hermle, is equipped with a Siemens 840D controller, which is modified with a Step-NC interpreter and the appropriate user interface.
In test scenarios, generated code from Dassault and OpenMind systems feeds into the Siemens control. For this, a Step-NC output filter expands the Catia V5 and OpenMind/Vamos CAM applications. The Step-NC control understands the new data format and displays the necessary working steps on the operators panel.
If necessary, all the information belonging to the working step can be displayed and modified. This includes deleting or generating working steps. Operators can also edit the sequence of working steps to optimize machine movements.
When a machine's supplied tooling is not defined, the type of operation can also be changed -- for example, enlarging a hole by milling instead of drilling. These modified data sets then directly generate a new physical file, which is archived.
After this, operators simulate the working steps and make any last corrections, such as...