Difference between CNC lathes and turning centers


CNC lathes can be divided into two major categories: horizontal and vertical. Horizontal lathes can be further divided into two types: flat guide and slant guide. High-grade CNC horizontal lathes generally use slant guides. They can also be classified based on the number of tool holders, as single-turret CNC lathes and double-turret CNC turning centers, with the former having two-coordinate control and the latter having four-coordinate control.

Most double-turret horizontal lathes use slant guides.Like conventional lathes, CNC lathes are used to process rotating surfaces of parts. They can generally automatically complete the processing of external cylindrical surfaces, conical surfaces, spherical surfaces, and threads, and can also process some complex turning surfaces, such as hyperboloids. The method of workpiece installation for lathes is basically the same as that of conventional lathes. In order to improve processing efficiency, CNC lathes mostly use hydraulic, pneumatic, and electric chucks.

The appearance of CNC lathes is similar to that of conventional lathes, consisting of a bed, a spindle box, a tool holder, a feed system, a pressure system, a cooling and lubrication system, etc. The feed system of CNC lathes is fundamentally different from that of conventional lathes. Traditional lathes have a feed box and an exchangeable gear rack, while CNC lathes use servo motors to directly drive the carriage and tool holder through ball screws to achieve feed motion, thus simplifying the structure of the feed system greatly.

There are various types and specifications of CNC lathes, which can be classified by the following methods.

Classification by spindle position:

(1) Vertical CNC lathe, also known as CNC vertical lathe, has a spindle that is perpendicular to the horizontal plane and a large circular worktable for clamping workpieces. This type of machine is mainly used for processing large, complex parts with large radial dimensions and relatively small axial dimensions.

(2) Horizontal CNC lathe: categorized into rail types – horizontal and inclined guide rail variations.The inclined guide rail structure can make the lathe more rigid and easier to remove chips.

Classification by basic types of machined parts:

(1) Chuck-type CNC lathe, which does not have a tailstock and is suitable for turning disc-type (including short shaft-type) parts. The clamping method is often electric or hydraulic control, and the chuck structure often has adjustable jaws or non-quenched jaws (i.e., soft jaws).

(2) Center-type CNC lathe, which is equipped with a common tailstock or CNC tailstock, is suitable for turning longer parts and disc-type parts with a smaller diameter.

Classification by number of tool holders:

(1) Single-tool CNC lathe, which is typically equipped with various forms of single-tool holders, such as a four-position horizontal indexing tool holder or a multi-position turret automatic indexing tool holder.

(2) Double-tool CNC lathe, which has two tool holders arranged in parallel or perpendicular to each other.

Classified by Function:

(1) Economical CNC lathe: a simplified lathe with stepper motor and microcomputer feeding system. It has low cost but low automation and functionality, and the machining accuracy is not high. It is suitable for the turning processing of rotary parts with low requirements.

(2) General CNC lathe: custom-designed with universal CNC system for turning processing needs.The CNC system has strong functions, high automation, and machining accuracy. It is suitable for the turning processing of general rotary parts. This type of CNC lathe can simultaneously control two coordinate axes, namely X-axis and Z-axis.

(3) Turning centers: based on the general CNC lathe, it adds the C-axis and power head. Advanced CNC turning centers have tool magazines and can control X, Z, and C three coordinate axes. The linkage control axis can be (X, Z), (X, C), or (Z, C). Due to the addition of the C-axis and milling power head, the machining functions of this type of CNC lathe are greatly enhanced. In addition to general turning, it can also perform radial and axial milling, contour milling, drilling of holes that are not in the center of rotation of the workpiece, and drilling of radial holes, etc.

Other Classification Methods:

According to different control modes of CNC systems and other indicators, CNC lathes can be classified into many types, such as linear control CNC lathes, dual-spindle control CNC lathes, etc. According to special or specific process performance, they can be classified into various types such as thread CNC lathes, piston CNC lathes, crankshaft CNC lathes, etc.