Machine Control Aimed At Job Shops And Beyond
The Sinumerik 828D control is said to bring to the "job shop machine tool" a range of features and functionality typically reserved for high-end machine tools.
Traditionally, there has been a distinction between the machine tool control technology applied to machine tools for job shops and that applied to machines for complex mold work and high-volume production. The Sinumerik 828D control, recently introduced by Siemens Drive Technologies Motion Control (Elk Grove Village, Illinois), largely erases this difference, thus bringing to the "job shop machine tool" a range of features and functionality typically reserved for high-end machine tools, the company says. The intent is to give job shops a boost in four areas considered key to profitable growth: innovation, productivity, globalization and process capability. These are the same areas on which large manufacturers and corporations rely to stay competitive in world markets.
The Sinumerik 828D is being billed as a control that allows machine tool builders to meet the needs of machine tool buyers around the world. For example, the control is capable of graphical, high-level language command but also supports ISO programming. Likewise, the control can be configured for milling or turning applications to simplify builders’ installation requirements while providing users with a common operator interface panel and highly similar interfaces.
The milling version is designed for VMCs with additional rotary axes for machining cylindrical workpieces or inclined workpiece planes. The turning version is designed for slant-bed lathes with turrets that have live tooling, including those with Y-axis capability, thus supporting a fully functional counter spindle. For both versions, a system called Easy Extend makes it simpler for the machine tool builder to interface with additional components such as indexers, rotary tables, chip conveyors or bar feeders.
Several of the control’s more advanced features are of special interest to shops doing complex contouring and mold machining. For example, 80-bit floating "NANO Accuracy" allows the control to process contouring commands that have resolution in nanometers. This feature is said to enhance high speed finish machining of complex surfaces that must meet tight dimensional tolerances and high surface quality requirements.
Another feature, "Advanced Surface," also benefits mold machining. This feature is designed to improve workpiece surfaces while significantly reducing machining time. According to the company, mathematical lookahead algorithms calculate back and forth tool paths in the same way, thus creating smooth workpiece surfaces.
Other features deal with asset utilization issues. For example, "Production Status" automatically sends a mobile phone text message when a machine needs new blanks, is out of tolerance or any alert/alarm parameter (as selected by the user) is tripped. "Contour Calculator" allows the shopfloor programmer to define complex or simple shapes from a drawing, while "CAD Reader" allows a CAD-generated DXF file to be imported into the format the 828D needs. "Animated Elements" allows the CNC operator to open help screens for the field that is highlighted in the graphical user interface rather than consult a paper manual. Automatic measuring cycles simplify setup of a workpiece or tool offset. Finally, the control has provisions to ease integration into shop networks, including the use of USB, Compact Flash and Ethernet ports for high speed data transfer and storage.
The Sinumerik 828D will be displayed on machine tools from 11 builders at the upcoming EMO show in Milan, Italy.
It is common to machine several identical workpiece attributes from within a single program. Consider the four identical circular counter-bored holes that must be milled in the workpiece shown in Figure 1.
Today, computer numerical control (CNC) machines are found almost everywhere, from small job shops in rural communities to Fortune 500 companies in large urban areas.
This perspective for a good programmer is a practical one, since the CNC operator must understand the machine's basic components, its directions of motion, and all buttons and switches available on the machine tool itself.