The Conventional Gantry Type Milling Machine, often referred to as a Gantry Mill, is a large and powerful milling machinery used for precision machining of heavy and oversized work-pieces. It is characterized by its unique gantry-style structure. This kind of milling machine is typically operated manually, don’t have CNC Control System, with the operator manual controlling the machining process. 

There are three main types of Double Column Machining Center in the industry which includes Moving Gantry Machining Center, Conventional Gantry Type Milling Machine and Fixed Gantry Machining Center.

The most distinctive feature is the presence of two vertical columns that are widely spaced apart, creating a bridge-like structure. This design provides exceptional rigidity and stability, reducing vibrations and ensuring accurate machining. And the worktable is positioned between the two columns and is capable of supporting large and heavy work-pieces. It can move vertically (Z-axis) and horizontally (X-axis) to position the work-piece for machining.

The Double Column Machining Center is a type of computer numerical control (CNC) Milling Machinery designed for precision machining of large and heavy duty work-pieces. It is characterized by its unique double column structure, where two vertical columns provide support and stability for the machine's components and the work-piece. This design allows the machine to handle exceptionally large and heavy work-pieces while maintaining high precision and accuracy.