Introduction To CNC Machine Tools
CNC machine tool is the abbreviation of digital control machine tool, which is an automatic machine tool equipped with a program control system. The control system can logically process the program with control codes or other symbolic instructions, and decode it, so as to make the machine tool move and process the control unit of the parts. The operation and monitoring of the CNC machine tool are all completed in this CNC unit. It is the brain of CNC machine tools.
High processing precision and stable processing quality;
Multi-coordinate linkage can be carried out, and parts with complex shapes can be processed;
When machining parts change, generally only need to change the CNC program, which can save production preparation time;
The machine tool itself has high precision and high rigidity, can choose a favorable processing amount, and has high productivity (generally 3~5 times of ordinary machine tools);
The machine tool has a high degree of automation, which can reduce labor intensity;
The requirements for the quality of the operators are higher, and the technical requirements for the maintenance personnel are higher.
CNC machine tools generally consist of the following parts:
The host is the main body of the CNC machine tool, including the machine body, column, spindle, feed mechanism and other mechanical components. It is a mechanical part used to complete various cutting processes.
The numerical control device is the core of the numerical control machine tool, including hardware (printed circuit board, CRT display, key box, paper tape reader, etc.) and corresponding software, used to input digital part programs, and complete the storage of input information and data Transformation, interpolation calculation and realization of various control functions.
The drive device is the drive component of the CNC machine tool actuator, including the spindle drive unit, feed unit, spindle motor, and feed motor. It realizes the spindle and feed drive through the electric or electro-hydraulic servo system under the control of the numerical control device. When several feeds are linked, the processing of positioning, straight line, plane curve and space curve can be completed.
Auxiliary device, some necessary supporting parts of the index control machine tool, used to ensure the operation of the CNC machine tool, such as cooling, chip removal, lubrication, lighting, monitoring, etc. It includes hydraulic and pneumatic devices, chip removal devices, exchange worktables, CNC turntables and CNC indexing heads, as well as cutting tools and monitoring and detection devices.
Programming and other ancillary equipment can be used to program and store parts outside the machine.
CNC machining process description
CAD: Computer Aided Design, that is, computer-aided design. 2D or 3D workpiece or three-dimensional drawing design
CAM: Computer Aided Making, that is, computer-aided manufacturing. Use CAM software to generate G-Code
CNC: CNC machine tool controller, read in G-Code to start processing
CNC machining program description
CNC program can be divided into main program and subprogram (subprogram). Any part of repeated processing can be written by subprogram to simplify the design of main program.
Characters (numerical data) → words → single block → processing program.
As long as you open the Notepad in the Windows operating system, you can edit the CNC code, and the written CNC program can be simulated with simulation software to simulate the correctness of the tool path.
Description of basic functions of CNC machine tools
The so-called function commands are composed of address codes (English letters) and two numbers. Actions or functions with a certain meaning can be divided into seven categories, namely G function (preparation function), M function (auxiliary function), T function (tool function), S function (spindle speed function), F function (feed rate function), N function (single section number function) and H/D function (tool compensation function).
CNC machine tool reference point description
Usually when programming a CNC machine tool, at least one reference coordinate point must be selected to calculate the coordinate value of each point on the work drawing. These reference points are called zero point or origin. Commonly used reference points include mechanical origin, return reference point, Work origin, program origin.
Machine reference point : The machine reference point or called the machine origin, it is a fixed reference point on the machine.
Return reference points (Reference points): There is a return reference point on each axis of the machine. The position of these return reference points is accurately set in advance by the limit switch of the travel monitoring device as the return point of the worktable and the spindle.
Work reference points: Work reference points or work origins, which are the origin of the work coordinate system. The points are floating and set by the programmer according to their needs. They are generally set on the workbench ( Work) any position.
Program reference points (Program reference points): Program reference points or program origins, which are the reference points of all turning points in the work. This point must be selected when programming, so the programmer must select one when selecting Convenient points to facilitate the writing of programs.
Steel telescopic guide rail guard is made of high-quality 2-3mm thick steel plate by cold pressing, and it can also be stainless steel according to requirements. Special surface polishing will increase its value. We can provide corresponding rail protection types (horizontal, vertical, inclined, horizontal) for all types of machine tools.