In recent years, with the vigorous development of China's equipment manufacturing industry, the machine tool industry—being the "mother machine" of equipment manufacturing—has become increasingly prominent. To meet the diverse needs of industrial enterprises, machine tool manufacturers have been actively introducing high-precision machine tools.

In recent years, with the vigorous development of China's equipment manufacturing industry, the machine tool industry—being the “mother machine” of equipment manufacturing—has become increasingly prominent. To meet the diverse needs of industrial enterprises, machine tool manufacturers have been actively introducing high-precision machine tools.

As China’s industrial heavy-duty manufacturing accelerates, an increasing number of machine tool enterprises are recognizing the value and business opportunities in the heavy-duty machine tool sector and are preparing to gradually enter the competitive market for large-scale machine tools. Moreover, in recent years, with the commercialization of high-tech functional components for CNC machine tool products, more and more companies have been joining the development of the heavy-duty machine tool market.

Currently, the development trends in heavy-duty machine tools mainly include the following aspects: the demand for increasingly higher machine tool load-carrying capacities; users’ requirements for ever-larger spindle turning diameters; and the high-precision demands placed on machine tools with large turning diameters and heavy load capacities. As the core component of a machine tool, the spindle’s rotational accuracy directly affects the roundness, cylindricity, and runout accuracy of the machined parts. Moreover, the spindle structure adopted by the machine tool influences both the machine’s turning diameter and the worktable’s load-carrying capacity.

The spindle journal and the inner bore of the bearing housing should be machined to precise fit tolerances, matching the dimensions of the inner and outer rings of the centering bearing. The mating surface between the bearing housing and the machine tool base must be scraped and lapped to ensure both surfaces meet the required flatness and contact area, as well as to guarantee perpendicularity between the plane and the spindle axis. Similarly, the mating surfaces between the lower end face of the spindle and the upper end face of the bearing housing, as well as those between the tight ring and the loose ring of the thrust cylindrical roller bearing, also need to be scraped and lapped.