In recent years, with the advancement of numerical control (NC) machine tools and precision machining technologies, the demand for machine tool guidance systems has significantly increased. These systems play a crucial role in determining the machining accuracy, operational efficiency, and service life of the machines. Many industrial equipment manufacturers rely on linear guide rails produced by specialized domestic and international factories as key functional components. Linear rolling guides, which utilize hardened guide rails and preloaded ball or roller sliders as contact elements, are widely adopted due to their low friction coefficient, 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 inferior vibration damping performance because their contact surfaces are point- or line-based.
To address this issue, some rail manufacturers have attempted to increase the preload of the rolling guide system in an effort to enhance damping performance. However, practical testing has shown that this approach is not very effective. While increasing the preload may shift the resonant frequency, it does not significantly improve damping. On the contrary, higher preload increases deformation of the rolling elements, raises displacement resistance, and accelerates surface wear, all of which negatively impact the longevity of the guide system.
An effective solution to reduce vibration is to incorporate a vibration-damping element into the system. During the development of the "SHZ1044 Twin-spindle Vertical Turning Center," a collaborative project between industry, education, and research, we implemented two types of rolling guide vibration-reduction measures, achieving excellent results.
One method involves using a linear rolling guide equipped with a damper carriage. The front end of the SHZ1044 uses an inverted spindle motor, and during operation, the front spindle rotates at high speed while moving horizontally (X-axis) and vertically (Z-axis), making it prone to vibration. To mitigate this, we selected a roller guide mechanism with a damper carriage (Fig. 1a) for the X-way guide.
The damper carriage is made of a steel structure and features a special spraying process that coats its inner surface with sliding bearing material. The guide rail is then ground to form a 0.03 mm gap between the sliding bearing layer and the rail surface (Fig. 1b). This oil-filled gap acts as a squeeze film damper, providing excellent damping performance. The thin oil film also allows for capillary action, minimizing oil consumption. During operation, lubricating oil is simply dropped into the slide’s oil hole alongside the rolling slider. This type of vibration-reducing rolling guide maintains the original advantages of light and fast movement while adding significant damping capability.
Another method involves attaching a damping block to the rolling shoe of a linear rolling guide system. This damping block, also known as a damping shoe, is typically manufactured by specialized bearing or machine tool component factories and is used on imported machines. It is placed within the guide mechanism to cover as much area as possible, leaving a small gap between the block and the guide rail to create a squeeze film. We designed a damping block for the inverted Z-axis rail of the SHZ1044, using TURCITE soft band material on the mating surface to create a 0.03 mm gap. Oil holes were drilled, and the block was installed between the two roller slides, forming a rolling guide with vibration-damping functionality (Fig. 3).
Both methods—damper carriages and damping blocks—have been successfully applied to the SHZ1044 twin-spindle vertical turning center. The X-axis guides use RUDS damping slides from Germany’s INA Bearing Co., Ltd., while the Z-axis guides feature self-designed plastic damping shoes. These custom-made damping shoes are more cost-effective than imported alternatives and allow for flexible length adjustments based on the guide system size, making them economically viable.
Currently, damping rolling guides are rarely used in Chinese machine tools due to a lack of domestic manufacturing support. Through this article, we aim to promote the development and production of such components within China, ultimately contributing to the global competitiveness of the country’s machine tool industry.
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