Classification by processing program
Machining centers can be classified into two categories: boring and turning-milling.
1. Boring and milling
2. Turning and milling
According to the number of control axes
According to the number of control shafts, it can be divided into:
1. Three-axis machining center
2. Four-axis machining center
3. Five-axis machining center.
Location classification
(1) Horizontal machining center: refers to the machining center with the spindle axis parallel to the workbench, which is mainly suitable for machining box parts.
Horizontal machining centers generally have indexing turntable or numerical control turntable, which can process all sides of the workpiece; It can also be used for the joint motion of multiple coordinates in order to deal with complex spatial surfaces.
(2) Vertical machining center: refers to the machining center with the spindle axis perpendicular to the workbench, which is mainly suitable for machining complex parts such as plates, disks, molds and small shells.
Vertical machining centers generally have no turntable, and only process the top surface.
In addition, there are compound machining centers with vertical and horizontal spindles, and vertical and horizontal adjustable machining centers whose spindles can be adjusted into horizontal or vertical axes, which can process five surfaces of workpieces.
(3) Universal machining center (also known as multi-axis linkage machining center): refers to a machining center that can control the linkage change by machining the included angle between the spindle axis and the rotary axis of the workbench, and complete the machining of complex spatial curved surfaces. It is suitable for machining impeller rotors, dies, cutters and other workpieces with complex spatial curved surfaces.
The form of multi-process centralized machining is extended to other types of CNC machine tools, such as turning centers. The CNC lathe is equipped with multiple automatic tool changing devices, which can control more than three coordinates. In addition to turning, the spindle can stop or index, and the cutter rotates for milling, drilling, reaming and tapping, which is suitable for processing complex rotating parts.
According to the type of machinable workpiece
(1) boring and milling machining center
Boring and milling machining center is the earliest developed and most widely used machining center at present, so the machining center usually refers to boring and milling machining center. Its feed shaft can realize stepless speed change and multi-axis linkage control, the main shaft can also realize stepless speed change, and it can realize automatic clamping and loosening of tools (loading and unloading tools), with automatic chip removal and automatic tool change devices. Its main technological ability is mainly boring and milling, and it can also be used for drilling, expanding, reaming, sinking and tapping. Its processing objects mainly include: plane parts with a fixed angle (constant) between the processing surface and the horizontal plane, such as disk, sleeve and plate parts; The included angle between the machined surface and the horizontal plane is constantly changing. Box parts; Complex curved surface (cam, integral impeller, mold, spherical surface, etc.). ); The irregular shape of special-shaped parts requires multi-station mixed machining of points, lines and surfaces.
(2) Turning center
On the basis of CNC lathe, the turning center is equipped with a tool magazine and a manipulator, which greatly increases the number of tools it can choose to use. The turning center mainly focuses on turning, and can also be used for milling, drilling, expanding, reaming and tapping threads. Its machining objects mainly include: conical surface of complex parts and revolving body with complex curve as generatrix. In the turning center, we can also drill radial holes, milling cutter keyways, milling cutter cam grooves and spiral grooves, taper threads and variable pitch threads. Turning centers usually have the following two advanced functions.
1) The function of power tool means that some or all cutter positions on the tool rest can be rotated by rotating cutters (such as milling cutters and drills) through the power in the tool rest.
2)c-axis position control function can realize arbitrary position control in the circumferential direction of the spindle. Realize x-c and z-c linkage. In addition, some turning centers also have Y-axis function.
(3) Five-sided machining center
In addition to the functions of ordinary machining centers, five-sided machining centers are characterized by the vertical and horizontal conversion of spindle heads. With the support of CNC indexing table or CNC rotary table, hexahedral parts (such as box parts) can be clamped at one time for five-sided processing. This kind of machining center can not only greatly reduce the auxiliary time of machining, but also reduce the influence of positioning error caused by multiple clamping on the accuracy of parts.
(4) Turning and milling compound processing equipment
As the name implies, turn-milling compound processing equipment refers to processing equipment with turn-milling function. In this sense, the above-mentioned turning center also belongs to this kind of processing equipment. However, what is mentioned here generally refers to the complex machining equipment for large and heavy vehicles, in which the turning and milling function is equally powerful, and it can realize the machining of multiple curved surfaces of some large and complex parts (such as the integral propeller of large ships) at one time, so that the machining accuracy of the parts' surfaces and the mutual position accuracy of the machined surfaces (such as the mutual position accuracy of propeller blade surfaces, positioning holes and mounting and positioning surfaces, etc.) are guaranteed by the accuracy of the equipment. This kind of equipment is listed as a national strategic material by western developed countries because of its high technical content, high price and obvious military application background, and is usually restricted and blocked in China.