CNC Machining Prototype & Parts Manufacturing Service
- PRODUCT DETAIL
CNC machining prototype service. Refers to a process method for turning and milling parts on CNC machine tools. The process specifications of CNC machine tool processing and traditional machine tool processing are generally consistent, but significant changes have also taken place. A machining method that uses digital information to control the displacement of parts and tools. It is an effective way to solve the problems of variable parts, small batches, complex shapes, and high precision, and to achieve high-efficiency and automated processing.
What is CNC machining?
Numerical control processing means that the control system issues instructions to make the tool perform various movements that meet the requirements. In the form of numbers and letters represent the shape and size of the workpiece and other technical requirements and processing requirements of the processing. It generally refers to the process of processing parts on CNC machine tools.
CNC machine is a computer-controlled machine tools. Whether it is a special computer or a general-purpose computer, it is collectively referred to as a numerical control system. The movement and auxiliary actions of the CNC machine tool are controlled by the instructions issued by the CNC system. The instructions of the CNC system are compiled by the programmer according to the material of the workpiece, the processing requirements, the characteristics of the machine tool, and the instruction format (numerical control language or symbols) prescribed by the system. The numerical control system sends out operation or termination information to the servo device and other functional components according to the program instructions to control various movements of the machine tool. When the part processing program ends, the machine tool will automatically stop. For any kind of CNC machine tool, the CNC machine tool cannot work without inputting program instructions in its CNC system. The controlled actions of the machine tool roughly include the start and stop of the machine tool; Spindle start and stop, direction of rotation and speed of the transformation; The direction, speed and mode of the feed movement; Tool selection, length and radius compensation; Replacement of tools, the cooling liquid opened, closed, etc.
NC programming
There are manual (manual) programming and automatic programming methods for NC machining programming. Manual programming, the entire content of the program is manually written in accordance with the instruction format specified by the CNC system. Automatic programming is computer programming, which can be divided into automatic programming methods based on language and drawing. However, no matter what kind of automatic programming method is adopted, corresponding hardware and software are required. It can be seen that the realization of CNC machining programming is the key. But programming alone is not enough. Numerical control processing also includes a series of preparatory work that must be done before programming and post-programming work. Generally speaking, the main contents of CNC machining process are as follows:
⑴ Select and confirm the parts and contents for CNC machining;
⑵ Process analysis of CNC machining of parts drawings;
⑶ Process design of CNC machining;
⑷ Mathematical processing of parts drawings;
⑸ Compile the processing procedure list;
⑹ Make the control medium according to the procedure list;
⑺ Check and modify the program;
⑻ First piece trial processing and on-site problem handling;
⑼ Formulation and filing of CNC machining process documents.
In order to improve production automation, shorten programming time and reduce CNC machining costs, a series of advanced CNC machining technologies have been developed and used in the aerospace industry. Such as computer numerical control, that is, use a small or microcomputer to replace the controller in the numerical control system, and use the software stored in the computer to perform calculation and control functions. This soft-connected computer numerical control system is gradually replacing the initial state numerical control system. Direct numerical control is to use one computer to directly control multiple numerical control machine tools, which is very suitable for small batch and short cycle production of aircraft. The ideal control system is an adaptive control system that can continuously change processing parameters. Although the system itself is complex and expensive, it can improve processing efficiency and quality. In addition to the improvement of CNC systems and machine tools in terms of hardware, the development of CNC has another important aspect that is the development of software.
In order to improve production automation, shorten programming time and reduce CNC machining costs, a series of advanced CNC machining technologies have been developed and used in the aerospace industry. Such as computer numerical control, that is, use a small or microcomputer to replace the controller in the numerical control system, and use the software stored in the computer to perform calculation and control functions. This soft-connected computer numerical control system is gradually replacing the initial state numerical control system. Direct numerical control is the direct control of multiple numerical control machine tools with one computer, which is very suitable for small batch and short cycle production of parts. The ideal control system is an adaptive control system that can continuously change processing parameters. Although the system itself is complex and expensive, it can improve processing efficiency and quality. In addition to the improvement of CNC systems and machine tools in terms of hardware, the development of CNC has another important aspect that is the development of software. Computer-aided programming (also called automatic programming) is after the programmer writes the program in CNC language. Input it into the computer for translation, and finally the computer automatically outputs punched tape or tape. The most widely used CNC language is APT language. It is roughly divided into main processing program and post processing program. The former translates the program written by the programmer to calculate the tool path; The latter compiles the tool path into a part processing program of a CNC machine tool. Numerical control processing is to write programs on the computer in advance before processing the workpiece, and then input these programs to the machine tool controlled by the computer program for command processing. Or directly write instructions for processing on the machine tool control panel controlled by this computer program. The machining process includes: tool moving, tool change, speed change, direction change, stop cutting, etc., which are all completed automatically. CNC machining is an advanced method of modern mold manufacturing and processing. Of course, numerical control processing methods must not only be used for mold parts processing, but also have a wide range of uses.
Machining accuracy
Number of CNC machining errors: Is edited by programming error △, Machine tool error△machine, Positioning error △ fixed, The tool setting error is △ knife, and the equal errors are formed comprehensively.
Namely: △number plus=f (△editing+△machine+△fixing+△tool)
among them:
1. Programming error △ is composed of approximation error δ and rounding error. The approximation error δ is produced in the process of approximating a non-circular curve with a straight line segment or a circular arc segment, as shown in Figure 1.43.
The rounding error is the error caused by rounding the coordinate value to an integer pulse equivalent value during data processing.
Pulse equivalent refers to the displacement of each unit pulse corresponding to the coordinate axis. Normal precision CNC machine tools, the general pulse equivalent value is 0.01mm;
The pulse equivalent value of more precise CNC machine tools is 0.005mm or 0.001mm, etc.
2. Machine tool error △machine: It is caused by CNC system error and feed system error.
3. Positioning error △Fixed: it is caused when the workpiece is positioned on the fixture and the fixture is positioned on the machine tool.
4. Tool setting error △Knife: It is generated when determining the relative position of the tool and the workpiece.
