如果不通过适当的冷却来精确控制温升，就无法开发出加工部件更精确、更稳定和更高精度的机床。机床冷却器是避免机床主轴中心线偏差的最佳油温（或水温）管理器。然而，在高速加工过程中，机床冷却器面临着冷却温度的控制波动和热负荷的剧烈变化。在本研究中，采用热气旁通方案进行了实验研究，以评估工艺冷却水的温度控制精度。研究了在工艺冷负荷和不同节流装置变化的情况下，采用脉宽调制（PWM）技术对旁通阀进行延迟时间控制的效果。温度控制的准确性以及开启频率- 综合比较了不同负载和不同延迟时间下的停机时间。实验结果表明，通过调节热气旁通阀控制5秒的延迟时间，可以实现冷却水温度0.2°C（0.36°F）以内的控制精度。提出的具有PWM控制延时方案的热气旁通冷却系统不仅比逆变器驱动系统更具成本效益，而且可以为旁通电磁阀提供更高的耐用性，并针对高精度过程冷却应用执行精确的温度控制。引文:内华达州拉斯维加斯ASHRAE会议论文

Machine tool with more accurate, stable and higher precision for the machining components cannot be developed without the precise control of the temperature rise by appropriate cooling. The machine tool coolers are the best managers of oil (or water) temperature in avoiding the deviation of spindle centerline for machine tools. However, the machine tool coolers are facing the control hunting of cooling temperature and the dramatic variation of heat load during high speed machining. In this study, the experimental investigation using hot-gas by-pass scheme were conducted to evaluate the temperature control accuracy of process cooling water. Effects of delay time control use pulse width modulation (PWM) techniques for by-pass valve under variation of process cooling load and different throttling devices been have investigated. The accuracy of temperature control as well as the frequency of ON-OFF times under different loading and different delay time has been compared comprehensively. The experimental results revealed that control accuracy within 0.2°C (0.36 °F) of cooling water temperature can be achieved with 5 seconds delay time controlled by adjusting hot-gas by-pass valve. The proposed hot-gas by-pass cooling system with PWM controlled time delay scheme is not only more cost-effective than inverter-driven system, but also can provide higher durability for by-pass solenoid valve and perform precise temperature control specific for high-accuracy process cooling application.