What is a CNC machining center?
The CNC machining center, also known as a multi-process automatic tool switching CNC machine tool, is a metal cutting equipment with the largest output in the world. it is the most widely used in the modern machinery manufacturing industry.
The control system of a CNC machining center has many functions. The machine has at least three coordinate axes of motion and as many as a dozen axes. Its capabilities require at least two-axis control to achieve tool movement linear interpolation and circular interpolation. Some CNC manufacturing workshops are equipped with 5-axis, and 6-axis CNC equipment to complete the machining of more complex surfaces.
The CNC machining center also has various supporting functions. These play a positive role in improving the machining efficiency of the equipment and ensuring the machining accuracy and quality of the products.
- Machining fixed cycle
- Automatic tool radius compensation
- Automatic compensation of tool length
- Tool breakage alarm
- Tool life management
- Automatic protection for overload and overtravel
- Screw pitch error compensation
- Screw gap compensation
- Automatic fault diagnosis
- Graphic display of workpiece and machining process
- Human-machine dialogue
- On-line workpiece inspection
- Off-line programming
The outstanding feature of the CNC machining center is that it is built with a tool library in which various tools or inspection tools are stored. It is automatically selected and replaced by the program during the machining process. This is the main difference between it and the CNC milling machine and the CNC boring machine.
The 4 types of CNC machining centers according to the different functional characteristics.
- Boring and milling CNC machining center
The boring and milling machining center is mainly used in boring and milling parts or prototypes. It is suitable for manufacturing cases, shells, and various complex parts with special curves and curved contours. The term “machining center” generally refers specifically to the boring and milling machining center. Other functions of the machining center need special descriptions, such as turning CNC machining center, drilling CNC machining center, etc.
- Drilling CNC machining center
The drilling machining center is used for drilling processing. The tool holder is based on the turret head. It is suitable for producing small and medium-sized parts such as drilling, reaming, reaming, and tapping threads.
- Turning CNC machining center
The turning machining center is mainly for turning. The master object is a CNC lathe. The machine tool is equipped with a turret-type tool library or a tool library consisting of a tool changer robot and a chain tool library. The machine tool CNC system is mostly two or three axes, i.e. X, Z, and C axes. Some high-performance turning centers are equipped with milling power heads.
- Complex precision CNC machining center
If a CNC machining center can complete multi-process machining such as turning, milling, boring and drilling on one piece of equipment, it is called a compound machining center. It can replace multiple machine tools to realize five-sided composite machining. This method can not only reduce loading and unloading time, and improve production efficiency, but also ensure and improve shape and position accuracy.
Vertical machining center and horizontal machining center
This classification is mainly based on whether the CNC machining center spindle is placed vertically or horizontally.
Vertical CNC machining center
A vertical CNC machining center is a machining center with a vertical axis. Its structure is mostly in the form of a fixed cylinder with a rectangular table and no indexing rotary function. It is suitable for machining disc, sleeve, and plate-type components.
It generally has two linear motion coordinate axes and can install a rotary table along the horizontal axis of rotation on the table, which is used to process spiral parts.
The vertical machining center is convenient to install and operate. It is also easy to debug the program.
However, due to the limitation of the column height and tool changer, it cannot machine parts that are too high. When machining cavities or concave surfaces, chips are not easily discharged and can seriously damage the tool and the machined surface.
Horizontal CNC machining center
Horizontal machining center refers to the machining center whose axis is horizontal. The horizontal machining center usually has a rotary table with automatic indexing. It usually has 3 to 5 motion axes. The common one is three linear motion axes and one rotary motion axis.
The workpiece is machined on the remaining four surfaces except for the mounting surface and the top surface after a single setup. It is most suitable for machining box-type parts.
Compared with the vertical machining center, the horizontal machining center is easy to discharge chips, but the structure is complicated and the price is higher.
What are the differences between horizontal machining centers and vertical machining centers?
- Different axis structure
The axis of the horizontal machining center is horizontal.
The axis of the vertical machining center is vertical.
- Different working table
The table of the horizontal machining center, designed to move in X or Y direction, the table is usually a rotatable dotted screw hole table.
The table of the vertical machining center is usually a T-slot table with cross slide structure. There are two sets of motion mechanisms for the mutual vertical direction of movement.
The difference in structure column
The columns of horizontal machining centers are designed as moving columns. The structure of the moving column requires that the column must be as light as possible while meeting the premise of rigidity.
Vertical machining center column is generally designed not to move. In the pursuit of rigidity, they are generally manufactured to be as stout as possible.
Different chip discharge
The vertical machining center is not easy to discharge the chips when machining the cavity or the concave surface.
The horizontal machining center is easy to discharge chips when machining.
Different machining objects
The horizontal machining center is suitable for machining box-type parts and can realize five-sided machining after adding an angle head.
Vertical machining center, suitable for processing disk, set, and plate parts. The size of the machined workpiece is relatively small.
The horizontal machining center machined workpieces are bigger. Clamping operation debugging is relatively difficult.
And the vertical machining center clamping is usually very convenient. Operation and debugging program is easy.