In recent years, with the advancement of numerical control machine tools and precision machining techniques, the demands on the guidance systems of these machines have significantly increased. The guidance system plays a crucial role in determining the machining accuracy, work efficiency, and service life of the machine. Many equipment manufacturers use specialized craft equipment factories—both domestic and international—to produce linear guide rails. These linear rolling guides feature hardened guide rails and preloaded balls or roller sliders as contact elements, offering advantages such as low friction, high load capacity, good rigidity, and long service life. They can achieve high feed rates and positioning accuracy. However, compared to traditional sliding guides, rolling guides tend to have lower vibration damping performance due to their point or line contact. Some manufacturers have attempted to enhance damping by increasing preload, but actual tests show this method is not very effective. While it may shift the resonant frequency, it doesn't significantly improve damping. In fact, higher preload increases deformation of the rolling elements, raises displacement resistance, accelerates surface wear, and ultimately reduces the lifespan of the guide components.
To effectively reduce vibration, adding a vibration-damping element is a more promising solution. During the development of the “SHZ1044 Twin-spindle Vertical Turning Center,†a collaborative project involving industry, education, and research, we implemented two types of rolling guide vibration-reduction measures, achieving excellent results. One approach involved using a damper carriage with a linear rolling guide. The front end of the "SHZ1044" features an inverted spindle motor that rotates at high speed and moves in the horizontal (X) and vertical (Z) directions, making it prone to vibration. To address this, we selected a roller guide mechanism equipped with a damper carriage for the X-axis guide (Figure 1).
The damper carriage consists of a steel structure body with its inner surface coated with a sliding bearing material via a special spraying process. The guide rail is then ground to create a 0.03 mm gap between the sliding bearing layer and the rail surface. This oil film acts as a squeeze film shock absorber, providing effective damping. Due to the thinness of the oil film, capillary action ensures minimal oil consumption. During operation, lubricating oil is simply dropped into the oil hole of the slide alongside the rolling slider. This vibration-reducing rolling guide system retains the original benefits of smooth and fast motion while also offering superior damping performance.
Another type of vibration-reducing mechanism involves attaching a damping block to the rolling guide. For a linear rolling guide pair made of a rectangular steel rail and a roller sliding shoe, a damping block can be added to the working plane. This damping block, also known as a damping shoe, is typically manufactured by specialized bearing or machine tool component factories. It is used in some imported machines and has shown good damping performance after installation (Figure 3). The damping block is placed within the guide mechanism, covering as much area as possible, and leaves a gap to form a squeeze film. This design allows it to function like a sliding guide without direct contact. We designed and manufactured a damping block for the inverted front Z-axis rail of the SHZ1044 machine. Made from steel or cast iron, the damping block is processed and fitted with a TURCITE soft band material before being matched with the corresponding guide rail to create a 0.03 mm gap. Oil holes are drilled, and the block is installed between two roller sliding shoes, forming a rolling guide with vibration-damping capabilities.
Using a damping slide or damping shoe also enhances impact safety, suppresses plastic deformation caused by impacts, and reduces mechanical damage. These two vibration-reducing methods were successfully applied to the SHZ1044 twin-spindle vertical turning center. The X-axis guide rails are equipped with RUDS damping slides from Germany's INA Bearing Co., Ltd., while the Z-axis guide rails use self-designed and manufactured plastic damping blocks. The cost of the self-made damping blocks is lower than imported alternatives, and their length can be customized based on the size of the guide mechanism, making them economically viable.
Currently, damping rolling guide systems with damper slides or shoes are rarely used in Chinese machine tools. A major reason is the lack of professional manufacturers in China to support such technology. Through this article, we hope to promote the domestic production and manufacturing of these vibration-damping components, encouraging the use of locally-made equipment and contributing to the global advancement of China's machine tool industry.
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