Graphite electrodes, as high-temperature and oxidation-resistant conductive materials, play a crucial role in the steelmaking process of the iron and steel industry. However, the yield and production cost of graphite electrodes place stringent demands on controlling process parameters. Selecting appropriate processing methods and closely monitoring each production process are essential to ensure that production parameters match the established process parameters.
To meet the automation needs of graphite electrode processing, Shanghai FANUC Robotics Co., Ltd. has developed a system that works with FANUC robots to automatically load and unload graphite electrodes and automate corner clearing, roughing, and contouring. The system mainly consists of one ROBOCUTα-C400iB wire EDM machine, one ROBODRILLα-D14MiB small machining center, one FANUC CR-7iA/L collaborative robot, and other supporting equipment. This system enables the robot to work in conjunction with multiple intelligent machines and allows for combined processing by different intelligent machines.
Figure 1 Automated system for graphite electrode processing
The loading and unloading of graphite electrodes is automated using the FANUC CR-7iA/L collaborative robot. As a small collaborative robot, the CR-7iA/L has a maximum payload of 7kg and a movement radius of 911mm. Its compact and agile size makes it ideal for human-robot collaboration in areas such as machine tool loading and unloading and electronic product assembly. Comprehensive safety features allow this green robot to work alongside humans without safety barriers.
The automated graphite electrode machining system showcases FANUC's latest series of slow-travel four-wire EDM machines, the α-C400iB. This series of linear EDM machines boasts advantages such as high speed, high precision, high performance, and high reliability. Equipped with the latest 31i-WB system, its superior operability, high degree of automation, and high machining accuracy significantly improve the efficiency of graphite electrode corner clearing.
Meanwhile, the automated graphite processing system uses the α-D14MiB mini machining center for electrode roughing and contour machining. This mini machining center can perform T-to-T tool changes within 0.9 seconds and offers some protection for graphite processing. The machine tool loading and unloading system, integrating the mini machining center with an intelligent robot, combines advantages such as high-efficiency production, stable operation, and space saving.
The system's workflow is as follows:
1) The robot uses vision to locate the machining center and then changes the material at the machining center;
2) The robot uses vision to locate the wire cutting position and then changes the material for the wire cutting machine;
3) After cleaning the workpiece, the robot returns the workpiece to the rack;
4) The machining center performs contour machining of the graphite electrode;
5) The graphite electrode is cleaned using a wire EDM machine.
The entire system also has the following features and advantages:
1) The combined processing of FANUC wire EDM and machining center equipment improves yield and production efficiency;
2) FANUC wire EDM machines feature the highly reliable AWF2 function, achieving a wire threading success rate of up to 99%; their CCR spindles have an indexing accuracy of ±4”.
3) The perfect integration of FANUC robots and intelligent equipment ensures safe and accurate loading and unloading of workpieces, improving system efficiency;
4) The Quick Start Package (QSSP) enables rapid connection between the robot and the target loading/unloading equipment.
This automated graphite electrode system boasts a high degree of automation and processing precision, meeting the daily production requirements of most domestic graphite electrode manufacturers. It effectively improves production efficiency, automation level, and product performance, while reducing labor intensity and labor costs, enabling products to stand out in the market.
