High-efficiency CNC lathes are classified according to process use:
Spindle large aperture lathe performance characteristics
1. The bed is made of high-quality high-strength cast iron, and the guide rail is treated by super-audio quenching with high precision and long service life.
2. The pallet adopts the guide surface surface molding technology, which is finely ground and scraped, with precise lubrication, with good processing dynamic performance and high precision retention.
3, the main shaft adopts independent spindle structure, large diameter, high rigidity, equipped with gearbox, low speed and large torque, suitable for heavy cutting; stepless speed regulation in each gear, wide application range.
4. The guide rail pair and ball screw pair are lubricated by single-line damping centralized lubrication pump, which is accurate and reliable.
5, semi-closed or fully enclosed protection, safety glass windows, bright work lights, user-friendly operating height, pleasant appearance.
High-efficiency CNC lathes are classified according to process use:
A CNC system has many functions, including basic functions----the necessary functions of the numerical control device; the selection function--the function for the user to select. Some of the selection functions are for solving different processing objects, some for improving the processing quality, some for the convenience of programming, and some high-efficiency CNC lathes for improving the operation and maintenance performance. Some selection functions are related, and you must choose another one. Therefore, according to the design requirements of the machine tool, do not add analysis, high-efficiency CNC lathe selection function too many steps, and the relevant functions are missed, so that the function of the CNC machine tool is reduced, causing unnecessary losses.
High-efficiency CNC lathe is the abbreviation of digital control machine tool, which is an automatic machine tool with program control system. The control system can logically process and decode the program with control code or other symbolic instructions to cause the machine to operate the CNC bending machine and machine the part.
High-efficiency CNC lathes are classified according to process use
Heavy cutting CNC lathes, including CNC lathes, CNC drilling machines, CNC milling machines, CNC grinding machines, CNC boring machines and machining centers. These machines are suitable for single-piece, small-batch and multi-variety and part machining, with excellent processing dimensional consistency, high productivity and automation, and high equipment flexibility.
Metal forming CNC machine tools; such machine tools include CNC bending machines, CNC combination punching machines, CNC pipe bending machines, CNC rotary head presses, etc.
CNC special processing machine tools; such machine tools include CNC wire (electrode) cutting machine tools, CNC EDM machines, CNC flame cutting machines, CNC laser cutting machines, special combination machine tools.
Other types of numerical control equipment; non-processing equipment uses numerical control technology, such as automatic assembly machines, multi-coordinate measuring machines, automatic plotters and industrial robots.
The basic components of high-efficiency CNC lathes include machining program carriers, numerical control devices, servo drives, machine tool bodies and other auxiliary devices. The basic working principle of each component is outlined below.
1, processing program carrier
When working on a heavy-duty CNC lathe, workers are not required to directly operate the machine. To control the CNC machine, a machining program must be programmed. The part processing program includes the relative motion trajectory of the tool and the workpiece on the machine tool, the process parameters (feedrate spindle speed, etc.) and auxiliary motion. The part processing program is stored in a program carrier, such as a punched paper tape, a cassette tape, a floppy disk, etc., with a certain format and code, and the program information is input to the CNC unit through the input device of the numerical control machine tool.
2, numerical control device
The core of high efficiency CNC lathes. Modern numerical control devices are all in the form of CNC. This CNC device generally uses multiple microprocessor shot blasting machines to realize numerical control functions in the form of programmed software. Therefore, it is also called Software NC. The CNC system is a position control system that interpolates the ideal motion trajectory based on the input data and outputs it to the parts required to machine the actuator. Therefore, the numerical control device mainly consists of three basic parts: input, processing and output. All of this work is reasonably organized by the computer's system program, allowing the entire system to work in harmony.
(1) Input device The numerical control command is input to the numerical control device, and there are different input devices depending on the program carrier. At present, there are mainly keyboard input, disk input, CAD/CAM system direct communication mode input and DNC (direct digital control) input to the upper computer. There are still many systems that still have the paper tape input form of the optical reader.
1) Paper tape input method. The paper tape photoelectric reader can be used to read the part program, directly control the movement of the machine tool, or read the contents of the paper tape into the memory, and control the movement of the machine tool by using the part program stored in the memory.
2) MDI manual data input method. The operator can use the keyboard on the operation panel to input the instructions of the machining program, which is suitable for relatively short programs.
In the control unit edit state (EDIT), the high-efficiency CNC lathe is used to input the machining program into the memory of the control unit. This input method can be used repeatedly. This method is generally used for manual programming.
On the numerical control device with session programming function, different menus can be selected according to the prompts on the display, and the machining program can be automatically generated by inputting the relevant size numbers by means of human-machine dialogue.
3) High-efficiency CNC lathe adopts DNC direct CNC input mode. The part program is saved in the upper computer, and the CNC system receives the subsequent block from the computer while processing. The DNC method is mostly used for complex workpieces designed with CAD/CAM software and directly generates part programs.
(2) The information processing input device transmits the processing information to the CNC unit, compiles it into a computer-recognizable information, and the information processing portion gradually stores and processes the information according to the control program, and then sends a position and speed command to the servo through the output unit. System and main motion control section. The input data of the CNC system includes: contour information of the part (starting point, end point, straight line, arc, etc.), machining speed and other auxiliary machining information (such as tool change, shifting, coolant switch, etc.). The purpose of data processing is to complete the insertion. Preparation before the complement operation. The data processing program also includes tool radius compensation, speed calculation, and processing of auxiliary functions.
(3) Output device The output device is connected to the servo mechanism. The output device receives the output pulse of the arithmetic unit according to the command of the controller, and sends it to the servo control system of each coordinate, and drives the servo system through power amplification, thereby controlling the machine tool to move according to the specified requirements.
The tool selection and cutting amount determination of the high-efficiency CNC lathe is completed under the human-computer interaction state, which is in sharp contrast with the ordinary machine tool processing. At the same time, the programmer must also master the basic principles of tool selection and cutting amount determination, high precision. CNC lathes fully consider the characteristics of CNC machining when programming, and can correctly select the cutting tool and the cutting amount. High-precision CNC lathes must be adapted to the high-speed, high-efficiency and high-automation characteristics of CNC machine tools. Generally, general-purpose tools, universal connecting shanks and a small number of special shanks should be included. The shank is connected to the tool and mounted on the power head of the machine, so it has been standardized and serialized.
High-efficiency CNC lathe control technology is a collection of computers. electronic. electric. Power drag. Automatic control and automatic measurement. mechanical. Hydraulic. Pneumatic as one of the high-tech. It better solves the complicated shape. Precision. Small and medium batch parts processing problems, along with computer-aided design. Computer aided manufacturing. The application of new technologies such as computer-aided processes, especially in automation and flexible manufacturing systems, plays an irreplaceable role, contributing to the continuous upgrading of products. To this end, it has also promoted the continuous improvement and development of CNC technology itself.
The narrow sense of high-precision CNC lathes is the machine tool that controls the movement of machine tools in the form of digital characters and completes machining. The CNC we often say refers to the emergence of computer numerical control machine tools in the late 1950s, and the rapid development of microcomputer technology after the 1970s. Now it has become an indispensable processing equipment in the machine industry.
The specific numerical values of high-efficiency CNC lathes should be based on the machine manual, the cutting amount manual, and the experience. High-precision CNC lathes should consider the following factors:
1. Cutting depth t. In the case where the machine tool, workpiece and tool stiffness allow, t is equal to the machining allowance, which is an effective measure to improve productivity. In order to ensure the machining accuracy and surface roughness of the parts, it is generally necessary to leave a certain amount of allowance for finishing. The finishing allowance of CNC machine tools can be slightly smaller than that of ordinary machine tools.
2. Cutting width L. Generally, L is proportional to the tool diameter d and inversely proportional to the depth of cut. In the processing of economical CNC machine tools, the general value range of L is: L = (0.6 ~ 0.9) d.
3. Cutting speed v. Increasing v is also a measure to increase productivity, but v is more closely related to tool durability. As v increases, tool durability drops dramatically, so the choice of v depends primarily on tool durability. In addition, the cutting speed is also very much related to the processing material. For example, when milling the alloy just 30CrNi2MoVA with an end mill, v can be about 8m/min; when milling the aluminum alloy with the same end mill, v can be more than 200m/min. .
4. Spindle speed n (r/min). The spindle speed is generally selected based on the cutting speed v. The calculation formula is: v=∏nd/1000. The control panel of the CNC machine tool is generally equipped with a spindle speed trimming (magnification) switch, which can adjust the spindle speed during the machining process.
5. Feed rate vF. The vF should be selected based on the machining accuracy and surface roughness requirements of the part as well as the tool and workpiece material. The increase in vF can also increase production efficiency. When the surface roughness of the machined surface is low, the vF can be selected to be larger. In the process of high-precision CNC lathe, vF can also be manually adjusted through the trim switch on the machine control panel, but the large feed rate of Zui is limited by the stiffness of the equipment and the performance of the feed system.
The programmable controllers in the selection function are available in both built-in and stand-alone models. Zui chooses the built-in type, it has different models, firstly according to the number of input and output signal points between the numerical control device and the machine tool. The number of points to be selected is slightly more practical, and a cup may add and change the need for control performance. Taiwan's CNC lathes secondarily estimated the sequential program size to select the storage capacity. As the complexity of the machine increases with the complexity of the machine, the storage capacity also increases, and it should be reasonably selected according to the specific situation. There are also technical specifications such as processing time, command function, timer, counter, internal relay, etc., and the quantity should also meet the design requirements.
High efficiency CNC lathe feed drive selection
(1) AC servo motor is preferred because it has smaller rotor inertia, better dynamic response, higher output power, higher speed, simple structure, lower cost and unlimited application environment compared with DC motor.
(2) Taiwan CNC lathes select the servo motor of the appropriate specification by correctly calculating the load conditions imposed on the motor shaft.
(3) The feed drive manufacturer provides a series of complete sets of products for the feed rate control unit and servo motor produced. Therefore, after selecting the servo motor, the corresponding speed control unit is selected from the product manual.
High efficiency CNC lathe spindle drive selection
(1) The main spindle motor is preferred because it does not have the same commutation, high speed and large capacity as the DC spindle motor. The constant power speed range is large, the noise is low, and the price is low. At present, 85% of CNC machine tools in the world use AC spindle drive.
(2) Select the spindle motor according to the following principles:
1 Calculate the cutting power according to different machine tools, the selected motor should meet this requirement;
2 According to the required spindle acceleration and deceleration time, calculate that the motor power should not exceed the maximum output power of the motor;
3 In the case where the spindle is required to frequently start and brake, the average power must be calculated, and the value cannot exceed the continuous rated output power of the motor;
4 Where constant surface is required to be controlled, the sum of the cutting power required for constant surface speed control and the power required for acceleration shall be within the power range that the motor can provide.
(3) Taiwan CNC lathe spindle drive manufacturer provides a series of complete sets of products for the spindle speed control unit and spindle motor produced. Therefore, after selecting the spindle motor, the corresponding spindle speed control unit is selected from the product manual.
(4) When the high-efficiency CNC lathe needs the spindle for directional control, according to the actual situation of the machine, the position encoder or magnetic sensor is used to realize the spindle orientation control.