Structural Features of the Longmen CNC Machining Center

The following section explains the structural features of the gantry-type CNC machining center.

　　1. Workbench

　　The worktable of the gantry-type CNC machining center is generally rectangular. Large castings such as the worktable, bed, column, crossbeam, and ram are made of cast iron or welded components. The internal cavities of these castings feature a honeycomb‑type composite structure, reflecting an advanced design. All components undergo stress‑relief treatment and secondary tempering to eliminate residual internal stresses and stabilize the material, thereby ensuring consistent machining accuracy and extending the machine tool’s service life.

　　2. Dragon Gate

　　The gantry consists of a crossbeam and two upright columns, and is available in three configurations: fixed crossbeam, crossbeam secured by positioning blocks, segmented lifting, and arbitrary crossbeam lifting.

　　3. Sliding saddle

　　Structurally, they can be classified into two types: open‑type and closed‑type. In the open‑type design, the ram is clamped to the spindle housing by a pressure plate, resulting in a larger cross‑sectional area; in the closed‑type design, the ram is housed within the spindle housing, with a smaller cross‑sectional area.

　　4. Tool magazine

　　There are three basic types of tool magazines: turret-type, drum-type, and chain-type.

　　5. Attachment Header Library

　　Machining large components typically requires numerous tooling attachments, which are specially designed to meet the specific machining requirements of the workpiece. These attachments are generally categorized into right-angle heads, extension heads, special‑angle heads, and universal heads.

　　6. CNC System

　　Currently, there are numerous CNC system suppliers, offering a wide range of brands and models to suit various requirements.

　　7. Accuracy

　　The accuracy of a machine tool refers to its initial precision under unloaded conditions. Accuracy is typically expressed as the deviation of its corresponding dimensions from the ideal state—commonly referred to as error. The smaller the error, the higher the accuracy.

　　Analysis of the CNC Lathe Industry and Program Development

　　CNC lathes are the cornerstone of modern machining equipment and underpin efficient, highly reliable, and highly flexible manufacturing processes. By fully leveraging the advantages of CNC lathes, production can reduce labor costs and minimize defective parts, while also controlling machining errors and achieving fully automated operation on a single machine.

　　Under conditions of fixed material, finishing allowance, and tool clamping, surface roughness is determined by the feed rate and cutting speed. When turning end faces on a conventional lathe, since the spindle speed remains constant throughout the cut, in theory only a specific diameter will yield relatively low roughness; in practice, however, end-face roughness often varies. By leveraging the constant‑linear‑speed cutting capability of a CNC lathe, one can select an optimal linear speed to produce end faces with lower, more uniform roughness. Moreover, CNC lathes are well suited for machining parts with differing surface‑roughness requirements: by increasing spindle speed while reducing feed rate and cutting allowance, it is possible to achieve very low roughness—something unattainable on conventional lathes. In applications where precision requirements are modest, a lathe can even substitute for grinding. Any planar curve can be approximated by an infinite series of short straight lines or small circular arcs; CNC lathes feature linear and circular interpolation functions, and some CNC controllers further support interpolation of non‑circular, complex curves. Consequently, they can machine rotationally symmetric components with intricate shapes, as well as parts whose dimensions are difficult to control due to combinations of straight lines and planar curves—for example, housings with enclosed internal cavities. Thanks to the computer’s powerful computational capabilities, which enable instantaneous, highly accurate determination of the torque and angular momentum required for each coordinate axis, CNC lathes can handle complex contouring that would be either extremely challenging or entirely beyond the reach of conventional lathes.

　　That’s all for today’s explanation. If you have any questions, feel free to contact me directly.