Double-column CNC vertical lathe and single-column CNC vertical lathe are two common CNC vertical lathes, and they have some differences in structure and function. Here are their main differences:

1. Structural design: Double-column CNC vertical lathe has two columns to support the worktable and headstock. This structure provides better rigidity and stability, and is suitable for processing larger and heavier workpieces. The single-column CNC vertical lathe has only one column to support the worktable and the spindle box, and its structure is relatively simple.
2. Processing range: Due to the more stable structure of double-column CNC vertical lathes, they are usually used to process larger workpieces, such as large brake discs, rollers, etc. The single-column CNC vertical lathe is suitable for processing smaller workpieces, suitable for small-scale parts production and batch processing.
3. Machining precision: Due to its stable structural design, the double-column CNC vertical lathe usually has high machining precision. Due to the relatively simple structure of the single-column CNC vertical lathe, the precision is slightly lower. This does not mean that single-column CNC vertical lathes cannot achieve high-precision machining, but that due to structural limitations, they may face some challenges when machining large workpieces.
4. Table size and load capacity: Double-column CNC vertical lathes usually have larger table sizes and higher load capacity, which can accommodate and process larger workpieces. The single-column CNC vertical lathe has a relatively small worktable, which is suitable for processing small workpieces.
5. Rigidity and stability: The double-column structure of the double-column CNC vertical lathe provides higher rigidity and stability, can withstand large cutting forces, and reduces vibration during processing. However, the structure of the single-column CNC vertical lathe is relatively simple, and it may be affected by vibration and deformation when processing larger workpieces.

The choice of double-column CNC vertical lathe or single-column CNC vertical lathe mainly depends on the specific processing requirements and workpiece characteristics. If you need to process larger and heavier workpieces, and require higher machining accuracy and stability, then a double-column CNC vertical lathe may be a better choice. For the production and processing of small workpieces, single-column CNC vertical lathes can provide sufficient performance and precision.