Characteristics of Additional Load Losses of Spindle System of Machine Tools

Abstract

Energy consumption of machine tool has drawn wide attention in recent years. The additional load losses of machine tools are of great importance for investigating the energy consumption of machine tools because those account for 15-20% of the cutting power and may even be up to nearly 30% of the cutting power in our researches. For lack of adequate understanding of the characteristics of additional load losses in the past, the additional load losses coefficient, defined as the ratio of additional load losses to cutting power, was regarded as a constant while the spindle speed was unchanged. However, it is discovered in our practical measurements that it is not so. In this paper, it proposes an additional load losses model based on power flow model, under the condition of the slip of spindle motor being small, in order to fully understand the characteristics of additional load losses. The characteristics of additional load losses include the relationship between additional load losses and cutting power, the relationship between additional load losses and spindle speed, and the relationship between additional load losses and cutting torque. Further more, an experimental system is developed to acquire the additional load losses through measuring cutting torque, spindle speed and input power of machine tool. As an example, several experiments are carried out on the CNC lathe by adjusting cutting parameters including spindle speed, feed rate and cutting depth. The experimental results show that the additional load losses coefficient varies with spindle speed and cutting torque, which can be fitted by a 1st order polynomial.

Energy Survey of Machine Tools: Separating Power Information of the Main Transmission System During Machining Process

“…Use ( ) a P t to substitute them, then formula (4) could be written as formula (5) (14) show that it's more accurate to approximate ( ) 1 α and 2 α are coefficients of the additional load loss. If we plug formula (6) into formula (4), we will get formula (7).…”

“…This method also faces the problem of accuracy, due to the difficulty to obtain enough optimized sample data in training the neural network. Kordonowy (13) sees the cutting power as the difference between total power and the idle power, which ignored the additional load power (1) .As the additional load power can sometimes reaches over 20% of the cutting power (14) , it clearly cannot be overlooked.…”

A new approach for calculating the input power of machine tool main transmission systems

“…The proposed PPF approach for calculating the input power of the MTS is available and convenient for machine tool users because only the motor input power is required, allowing a greater and wider practicability than the methods proposed by Liu et al 20 and Hu et al 22 Furthermore, the method can be implemented without any use of a torque (or moment) sensor, as is required in the traditional method. Furthermore, the PPF method can be widely used to study the energy efficiency and energy-saving technologies of machine tools, as discussed below: …”

The Analysis of Key Technologies for Sustainable Machine Tools Design

“…The studies concentrate on the energy transfer in the machining process, energy consumption and energy efficiency analysis and information monitoring, etc., based on the power and efficiency calculation of the main drive system. Furthermore, power balance equations of the main drive system frequency control of motor speed machine tool is established through the research of machine tool energy flow characteristics [45], which reveals the complex features of dynamic load loss of the main transmission system during the operation process of machine tools [46]. The factory-integrated machine tools are studied [47] to quantify the energy consumption at the level of the factory.…”