Numerical control center is developed from CNC milling machine. The biggest difference is that a machining center and CNC milling machine has the ability of automatic exchange tool, through the libraries installed on the different USES of the knives, can be in a clamping on the automatic tool change device to change the spindle tool, implement a variety of processing capabilities.
Nc machining center is an efficient automatic machine for machining complex parts, which is composed of mechanical equipment and nc system. Nc machining center is one of the most widely used CNC machine tools in the world. Its comprehensive processing ability is stronger, a clamping workpiece can be completed after more machining, the machining accuracy high, moderate difficulty of batch workpieces, its efficiency is 5 ~ 10 times of general equipment, in particular, it can accomplish many ordinary equipment can't finish machining, the shape is complex, high precision single processing or small batch more varieties of production is more suitable. It concentrates the functions of milling, boring, drilling, tapping and cutting thread on a single device, which has many technological means. The machining center is classified according to the space position of the main shaft: horizontal and vertical machining center. According to the technological use classification: boring milling machining center, compound machining center. According to the special classification of functions: single table, double table and multi-workbench processing center. Single shaft, double-axis, three-axis and the machining center of the main axle box.
The processing principle of
The determination of the processing route
CNC lathe feed processing route tool from the knife point movement began fixed origin (or machine), until the return to that point and end the route processing program, including cutting paths and cutting tool cut, cut out of the empty travel path.
The feed route of the precision machining is basically carried out along the contour sequence of its parts, so the key to determining the route is to determine the route of rough machining and empty stroke.
In nc lathe processing, the determination of processing route generally follows the following principles.
The accuracy and surface roughness of the workpiece shall be guaranteed.
The shortest route is to reduce the time of air travel and improve machining efficiency.
Try to simplify the work of numerical calculation and simplify the processing procedure.
A subroutine should be used for certain repetitive programs.
The advantages and disadvantages
Numerical control machining has the following advantages:
There is a lot of reduction in the quantity of work, and the complex parts are not required to be complicated. If you want to change the shape and size of the parts, you only need to modify the parts processing procedure for new product development and modification.
The processing quality is stable, the machining precision is high, the repeatability is high, and the processing requirements of the aircraft.
(3) many varieties, small batch production situations production efficiency is high, can reduce the production preparation, machine tool adjustment and process the test of time, and due to the use of optimal cutting quantity and reduces the cutting time.
It is difficult to process the complex surface of the conventional method, and can even process some unobserved machining parts.
The disadvantages of nc machining are the high cost of machine tool equipment and the higher level of maintenance personnel.
In nc machining center, there are usually two kinds of programming methods: simple contours - straight lines and circular arc shapes, which are directly programmed with the G code of nc system. Complex contours -- three-dimensional curved contour, draw 3d graphics with automatic programming software (CAD/CAM) in the computer, set various corresponding parameters according to the surface type, and automatically generate nc machining programs. The above two programming methods can basically meet the requirements of nc machining. But the function equation curve contour machining is difficult, because the early milling machine CNC system does not have functional operation function, with G code doesn't directly out of function equation curve machining program, version (lower) CAD/CAM software is usually does not have the function that directly by equation input graphics. So cutting function equation curve contour, the commonly used method is: according to the drawing requirements, calculate the coordinates of each point on the curve, and then according to the calculated coordinates with straight line or arc instruction code programming, manual input system for processing.