In CNC vertical lathes, line rails and hard rails are common types of guide rails, each of which has its own advantages and applicable scenarios.

1. Line rail (linear guide rail):
Advantages: The line guide adopts the design of bearing and ball raceway, which has the characteristics of low friction, high rigidity and high precision. It provides smoother and quieter motion and is suitable for high-speed machining, high-precision machining and small machine tools. The track structure is simple, easy to disassemble and assemble, and the maintenance cost is relatively low.
Applicable scenarios: Suitable for processing scenarios that require high speed, high precision and high rigidity, such as electronic product parts processing, precision machinery parts processing, etc.
2. Hard rail (rolling guide rail):
Advantages: The hard rail adopts the rolling method, and the worktable is carried by balls or rollers, which has high load capacity and wear resistance. It is suitable for large machine tools and heavy-duty processing, and has good absorption capacity for vibration and shock. Rigid rails are usually better than line rails in terms of load capacity and rigidity.
Applicable scenarios: Suitable for large workpieces or heavy load processing scenarios, such as auto parts processing, ship parts processing, etc.

The comprehensive selection should be judged according to the specific processing requirements and workpiece characteristics. If the requirements for high-speed, high-precision processing are high, and the load is small, line rails are a good choice. And if you need to handle heavy loads, large workpieces, and have high requirements for vibration and shock, hard rails are more suitable.
In addition, the specific machine tool model, manufacturer and configuration will also have a certain impact on the type of guide rail. Therefore, it is recommended to consult a professional machine tool manufacturer or technical expert to choose according to the specific situation.