The main motion of a machine tool should be speed-adjustable, and machine tool users pay more attention to the speed control function of frequency converters. Because machine tools have a wide processing range, different workpieces, different processes, and different cutting tools are used, frequency converters are most widely used in the lathe industry. Therefore, the main motion of a machine tool should be speed-adjustable, and machine tool users pay more attention to the speed control function of frequency converters. Currently, most of the frequency converters used in CNC machine tools in my country are Japanese brands. A frequency converter is a control device that uses the switching action of semiconductor devices to convert industrial frequency power into electrical energy of another frequency.
Currently, most of the frequency converters used in CNC machine tools in my country are Japanese brands. For example, Mitsubishi frequency converters are widely used in machine tools because their functions are similar to those of servo drives. Delta frequency converters, on the other hand, have similar functions to Mitsubishi but are much cheaper and have a high cost-performance ratio, so their market share has gradually increased in recent years.
In the lathe industry, frequency converters are used most extensively. However, Japanese brands such as Yaskawa, Fuji, and Mitsubishi, as well as Taiwanese brands like Delta, hold a significant market share. While some domestic brands of frequency converters are also used by machine tool manufacturers, in areas with higher performance requirements for frequency converters, such as grinding machines and forging presses, foreign brands like Mitsubishi, Fuji, Siemens, and Delta still dominate. Sales data for machine tools in 2008 and 2009 show that the inventory situation for general-purpose machine tools, especially complex lathes, is quite serious, while the market for composite machine tools and large heavy-duty products is better. These machine tools have a wide processing range, and their components have varying operating speeds, placing higher demands on the performance of frequency converters. Domestic frequency converter manufacturers should seize this opportunity to cultivate the machine tool market.
A frequency converter is a control device that uses the switching action of power semiconductor devices to convert mains frequency power into electrical energy of another frequency. It mainly consists of rectification (AC to DC), filtering, inversion (DC to AC), braking unit, drive unit, detection unit, and microprocessor unit. Generally speaking, a frequency converter must have several basic capabilities: 1. Speed regulation; 2. Protection functions. These can be divided into the following two categories:
(1) Automatically perform corrective actions after detecting abnormal conditions, such as overcurrent stall prevention and regenerative overvoltage stall prevention.
(2) Upon detecting an abnormality, the PWM control signal of the power semiconductor device is blocked, causing the motor to stop automatically. Examples include overcurrent cutoff, regenerative overvoltage cutoff, semiconductor cooling fan overheating protection, and instantaneous power outage protection.
Application of frequency converters in the machine tool industry
Because machine tools have a wide processing range, different workpieces, different processes, and different cutting tools require different movement speeds of the machine tool's actuators. Therefore, the main motion of the machine tool should be speed-adjustable, and machine tool users pay more attention to the speed adjustment function of frequency converters.
The spindle is a crucial component of a lathe, playing a vital role in improving machining efficiency, expanding the range of workable materials, and enhancing machining quality. Frequency converters are primarily used in spindle speed control systems. Currently, frequency converters offer excellent value for money for customers, making their use on lathes very common.
For general-purpose frequency converters to be used smoothly in the machine tool industry, two important considerations must be taken into account: first, choose products with sensorless vector control; and second, design them for overspeed operation to improve low-speed torque.
