It is now common for CNC machine tools to maintain a constant feed rate during machining, which is preset by the machining program. In order to ensure the safety of production, the compiler must set the feed rate according to the maximum load condition, but in fact this condition may only account for 5% of the entire process. So how to improve the machining efficiency of CNC machine tools, optimize the tool feed, and automatically protect the spindle system of the machine tool and expensive tools without damage has become a concern of end users and machine tool manufacturers. In order to solve this problem, Israel OMAT has applied adaptive control technology to CNC machine tools and developed a mature product, the OMAT CNC machine tool adaptive system, which has been widely used in the world.
2, the working principle
The adaptive control technology is applied to CNC machining by detecting the load of the machine tool spindle, using the internal expert system to analyze the collected spindle load signal and the corresponding tool and workpiece material data, and calculate the optimal feed of the machine tool in real time. The rate is applied to the CNC machining process, which greatly increases the production efficiency, and controls the feed rate stably, continuously and automatically during the machining process, and realizes the dynamic tool protection function (as shown in Fig. 1).
Figure 1 Adjust the tool feed rate in real time according to the change of cutting conditions
In the process of processing, the adaptive control system can learn and re-learn according to the input and output data of the control object, continuously identify the model parameters and correct them. As the production process continues, the model becomes more and more accurate, closer to reality, and finally adjusts itself to an optimal working state to optimize the machining process.
3, the main function
1) Greatly improve processing efficiency
The OMAT adaptive control system samples the load change of the machine tool spindle in real time, increases the feed rate under the condition of small load, reduces the feed rate under the condition of large load, and achieves the purpose of shortening the processing cycle and improving the processing efficiency.
2) Protect tools, machine tools and workpieces from damage
Conventional machining tool breakage is undetectable and control, tool wear is manually monitored, and efficiency is low. Under the control of the adaptive control system, the machining parameters are automatically adapted to the tool load and cutting conditions in real time. If an unexpected event occurs during processing, such as an impact on the tool or workpiece, the diameter of the workpiece blank increases too much, etc., the adaptive control system automatically reduces the feed rate to the safety value allowed by the internal expert system. If necessary, force the machine to stop. When these emergencies pass, the system increases the feed rate to the maximum allowed by the internal expert system, thereby effectively protecting the tool, reducing tool wear and thus extending tool life.
The OMAT adaptive control system has the following protection features:
Milling cutter break protection (alarm and stop to prevent damage to workpiece and subsequent tools)
Deep hole drill prop break protection (alarm and stop)
Tool wear monitoring (digital display wear)
Spindle overload protection (alarm or shutdown)
3) Real-time monitoring and recording of cutting conditions
The adaptive control system can monitor the CNC machining process in real time, and all the performance data (spindle cutting load, feed rate change, tool wear amount, number of workpieces, cutting time, etc.) in the cutting process can be generated in real time. Process report, and output graphics and data to the Windows user interface to form a complete machine file for management to evaluate and analyze, thus assisting production management. This data can also be stored on the hard drive for later review.
4, significant effect
Increasing processing efficiency is equivalent to reducing manufacturing costs! Typical application statistics: contour milling saves about 38%; milling slots save about 34%; 3D milling saves about 37%; drilling saves about 28%. If the processing efficiency of each equipment is calculated by 30% to 40%, then installing three Israeli OMAT excellent milling controllers (optimizing the adaptive control system for CNC milling machine processing) is equivalent to adding one CNC machine tool or machining center. Processing rate. According to the existing domestic and international use data calculation, it takes only 4 to 9 months to recover the investment for purchasing OMAT products.
In production, the adaptive control system learns to monitor tool wear while machining the first part. In subsequent machining, the system continues to monitor the condition of the tool and display it as a percentage of the tool's current wear level as a percentage of maximum wear. With the wear of the tool, the adaptive control system can automatically calculate the optimal feed rate according to the tool wear amount in real time, and remind the operator to change the tool when the tool wears to a certain extent. In this way, the NC programmer can set the feed as if using a new sharp tool. That is, the adaptive controller compensates for the wear of the tool.
In summary, factors such as protecting tools to extend their service life, protecting machine tools from downtime, and protecting workpieces from waste can further reduce costs and shorten your return on investment.
5, OMAT adaptive system application status and prospects
OMAT adaptive control system has been used by many famous foreign companies such as Siemens, Turbinenwerke, Chevron Aerospace, Boeing, General Electric, Mitsubishe Motors, Toshiba GE and Toyota Motors because of its remarkable practicability. Well-known enterprises in the domestic aerospace, textile, home appliances and other industries are also using this product. Jiaoda Kunji Technology Co., Ltd. cooperated with Israel OMAT Company to successfully integrate the system into the 840D system of the THM4680 horizontal machining center. It also made a large-face workpiece cutting comparison experiment, and the cutting rate increased by about 33%. These companies that have already used the OMAT CNC optimization system have achieved considerable economic benefits.
It is believed that with the continuous development and application of CNC machining technology, adaptive processing technology will be widely used, bringing rapid development to Chinese manufacturing enterprises.
Other Bearings,Angular Contact Ball Bearings,Deep Groove Ball Bearing,Bike Ball Bearings
HEBEI HAILAN BEARING MANUFACTURE CO.,LTD , https://www.hhbbearing.com