Metal CNC machining center is developed from CNC milling machine. The biggest difference from the CNC milling machine is that the machining center has the ability to automatically exchange machining tools. By installing tools for different purposes on the tool magazine, the machining tools on the spindle can be changed by the automatic tool changer in one clamping to realize multiple machining. Features.
The CNC machining center is a high-efficiency automated machine tool that is composed of mechanical equipment and a CNC system and is suitable for processing complex parts. The CNC machining center is currently one of the most widely used CNC machine tools in the world. Its comprehensive processing ability is relatively strong. After the workpiece is clamped, it can complete more processing content.
The processing accuracy is high. For batch workpieces with medium processing difficulty, its efficiency is 5 to 10 times that of ordinary equipment, especially it can complete Many processings that cannot be completed by ordinary equipment are more suitable for single-piece processing with more complex shapes and high precision requirements or for small and medium batch production of multiple varieties. It concentrates the functions of milling, boring, drilling, tapping and cutting threads on one equipment, so that it has a variety of processing methods. Machining centers are classified into horizontal and vertical machining centers according to their spatial position during spindle machining.
Classified according to process use: boring and milling machining center, compound machining center. According to the special classification of functions, there are: single workbench, double workbench and multi-workbench machining center. Machining centers with single-axis, dual-axis, three-axis and interchangeable headstocks. According to the classification of guide rails, there are linear rail machining centers, hard rail machining centers, etc.
Determination Of Machining Route
The feed processing route of the CNC lathe refers to the path that the turning tool moves from the tool setting point (or the fixed origin of the machine tool) until it returns to this point and ends the processing program, including the path of cutting processing and non-cutting such as cutting in and out of the tool Empty travel path.
The feed route of finishing is basically carried out along the part contour sequence. Therefore, the focus of determining the feed route is to determine the feed route of rough machining and idle stroke.
In CNC lathe processing, the determination of the processing route generally follows the following principles.
- It should be able to guarantee the accuracy and surface roughness of the workpiece to be processed.
- Make the processing route the shortest, reduce the idle travel time, and improve the processing efficiency.
- Simplify the workload of numerical calculation as much as possible and simplify the processing procedure.
- For some reusable programs, subroutines should be used.
Pros And Cons
CNC machining has the following advantages:
- The number of tooling is greatly reduced, and complex tooling is not required for processing parts with complex shapes. If you want to change the shape and size of the part, you only need to modify the part processing program, which is suitable for new product development and modification.
- The processing quality is stable, the processing precision is high, and the repeat accuracy is high, which is suitable for the processing requirements of the aircraft.
- The production efficiency is higher in the case of multi-variety and small batch production, which can reduce the time of production preparation, machine tool adjustment and process inspection, and reduce the cutting time due to the use of the best cutting amount.
- It can process complex profiles that are difficult to process by conventional methods, and even process some unobservable processing parts.
The disadvantage of CNC machining is that the cost of machine tools is expensive and requires a high level of maintenance personnel.
Metal CNC machining center is a high-efficiency automatic machine tool that is composed of mechanical equipment and CNC system and is suitable for processing complex parts. The CNC machining center is currently one of the most widely used CNC machine tools in the world. Its comprehensive processing ability is relatively strong. After the workpiece is clamped, it can complete more processing content. The processing accuracy is high. For batch workpieces with medium processing difficulty, its efficiency is 5 to 10 times that of ordinary equipment, especially it can complete Many processings that cannot be completed by ordinary equipment are more suitable for single-piece processing with more complex shapes and high precision requirements or for small and medium batch production of multiple varieties.
Metal CNC machining center is a kind of CNC machining machine with more functions. It concentrates the functions of milling, boring, drilling, tapping and cutting threads on one device, so that it has a variety of technological means. The machining center is equipped with a tool magazine, which stores different numbers of various tools or inspection tools, which are automatically selected and replaced by the program during the machining process. This is the main difference between it and CNC milling machine and CNC boring machine. Especially for workpieces that must use tooling and special equipment to ensure product quality and efficiency. This will save a lot of time and cost for the development and remodeling of new products, so that the company has strong competitiveness.
Machining centers are often divided into vertical machining centers and horizontal machining centers according to the state of the main shaft in space. The main shaft of the machining center in the vertical state in the space is called vertical machining center, and the main shaft in the horizontal state of the space is called horizontal. Type machining center. The spindle can be converted vertically and horizontally, called a vertical-horizontal machining center or a five-sided machining center, also called a compound machining center. According to the number of columns in the machining center, there are single-column type and double-column type (gantry type).
According to the number of coordinates of the machining center movement and the number of coordinates controlled at the same time: there are three axes and two linkages, three axes and three linkages, four axes and three linkages, five axes and four linkages, and six axes and five linkages. Three-axis and four-axis refer to the number of motion coordinates of the machining center. Linkage means that the control system can control the number of motion coordinates at the same time, so as to realize the position and speed control of the tool relative to the workpiece.
According to the number and function of the workbenches: there are single-workbench machining centers, double-workbench machining centers, and multi-workbench machining centers.
According to the machining accuracy: there are ordinary machining centers and high-precision machining centers. Ordinary machining center, the resolution is 1μm, the maximum feed speed is 15-25m/min, and the positioning accuracy is about l0μm. High-precision machining center with a resolution of 0.1μm, a maximum feed speed of 15-100m/min, and a positioning accuracy of about 2μm. The ones between 2～l0μm are more than ±5μm, which can be called precision level.
CNC Machining Center
The CNC machining center is a CNC machine tool that has a tool magazine and can automatically change tools, and can perform a variety of processing operations on the workpiece within a certain range.
The characteristics of the parts processed on the machining center are: After the parts to be processed are clamped once, the CNC system can control the machine tool to automatically select and replace the tools according to different procedures; automatically change the spindle speed, feed rate and the motion path of the tool relative to the workpiece. And other auxiliary functions, continuously and automatically perform multi-process processing such as drilling, countersinking, reaming, boring, tapping, and milling on each processing surface of the workpiece.
Since the machining center can complete a variety of processes intensively and automatically, it avoids human operation errors, reduces workpiece clamping, measurement and machine tool adjustment time and workpiece turnover, handling and storage time, greatly improving processing efficiency and processing accuracy , So it has good economic benefits. The machining center can be divided into a vertical machining center and a horizontal machining center according to the position of the spindle in the space.
In CNC machining centers, there are usually two programming methods today:
- Simple contours-contours composed of straight lines and arcs, directly programmed with G codes of the CNC system.
- Complicated contours-three-dimensional surface contours. Use automatic programming software (CAD/CAM) to draw three-dimensional graphics in the computer, set various corresponding parameters according to the surface type, and automatically generate CNC machining programs. The above two programming methods can basically meet the requirements of CNC machining.
But it is very difficult to process the contour of the function equation curve, because the early milling machine numerical control system does not have the function of function calculation, and the processing program of the function equation curve cannot be compiled directly with G code, and the (lower version) CAD/CAM software usually does not It has the function of directly inputting graphics from equations. Therefore, the cutting function equation curve profile is usually used: calculate the coordinates of each point on the curve according to the requirements of the drawing, and then use the straight line or arc command code to compile the program according to the calculated coordinate value, and manually enter the system for processing.
The machining center is a high-efficiency, high-precision CNC machine tool. The workpiece can be processed in multiple procedures in one clamping. At the same time, it also has a tool library and an automatic tool change function. These rich functions of the machining center determine the complexity of the programming of the machining center.
The machining center can realize three-axis or more linkage control to ensure that the tool can process complex surfaces. In addition to linear interpolation and circular interpolation, the machining center also has various machining canned cycles, automatic tool radius compensation, automatic tool length compensation, processing graphics display, man-machine dialogue, automatic fault diagnosis, offline programming, etc. .
The machining center is developed from the CNC milling machine. The biggest difference from the CNC milling machine is that the machining center has the ability to automatically exchange machining tools. By installing tools for different purposes on the tool magazine, the machining tools on the spindle can be changed by the automatic tool changer in one clamping to realize multiple machining. Features.
Machining centers can be divided into vertical, horizontal and compound machining centers in terms of appearance. The main shaft of the vertical machining center is perpendicular to the worktable, which is mainly suitable for processing plate and shell workpieces, and can also be used for mold processing. The spindle axis of the horizontal machining center is parallel to the worktable surface. Most of its worktable is a CNC rotary table controlled by a servo motor. In the one-time clamping of the workpiece, the machining of multiple processing surfaces can be realized through the rotation of the worktable, which is suitable for Box-type workpiece processing. The compound machining center mainly refers to a machining center with two vertical and horizontal spindles or the spindle can change the angle by 90°, so it can realize the processing of five faces in one clamping of the workpiece.
- Fault 1: The serial encoder communication error alarm of the CNC machining center, the reason: the unit detects that the motor encoder of the CNC machining center is disconnected or the communication is poor. Check whether the connection between the encoder feedback wire of the motor and the amplifier is correct and firm. If the feedback line is normal, replace the servo motor (because the encoder of the motor is integrated with the motor and cannot be disassembled), if it is an α motor, replace the encoder. If it happens occasionally, it may be caused by interference. Check whether the shielded wire of the motor feedback wire is intact.
- Fault 2: The encoder pulse count error alarm of the CNC machining center (LED display 6, the system PMM screen displays 303/304/305/308 alarm) Cause analysis: The serial encoder of the servo motor loses pulses or does not count during operation . Turn off and on again, if the same alarm still exists, replace the motor (replace the encoder if it is an α motor) or the feedback cable. If the alarm disappears after restarting the CNC machining center, you must return to the reference point before running other instructions. If the PMM of the system is 308 alarm, it may be caused by interference, turn off and then turn on.