2020 – Page 15 – CNC Machining & Turning, Milling, Metal parts

Self inspection of computer gong processing

The processing procedure of self inspection of computer gong 1. The processor must see the contents of process card before processing, know the parts, shape, drawing dimensions of the workpiece to be processed and know the processing contents of the next process. 2. Before clamping, the blank size shall be measured to meet the requirements of the drawing. When clamping, it is necessary to carefully check whether the placement of workpiece is consistent with the programming operation instruction. 3. After rough machining, self inspection shall be carried out in time to adjust the error data in time. The self inspection content is mainly the position dimension of the processing part. For example: (1) whether the workpiece is loose; (2) whether the workpiece is correctly divided; (3) whether the dimension from the processing part to the reference edge (reference point) meets the requirements of the drawing; (4) the position dimension between the processing parts. After checking the position dimension, the rough machined shape ruler shall be measured (except for circular arc). 4. After rough machining, the finishing can be carried out only after self inspection. After finishing, workers shall check the shape and dimension of the processed parts: check the basic length and width dimensions of the processing parts of the vertical plane; measure the base point dimension on the drawing for the machining parts of the inclined plane. 5. The workers can remove the workpiece and send it to the inspector for special inspection after they have completed the self inspection of the workpiece and confirmed that they are in conformity with the drawings and process requirements. High speed CNC is based on the characteristics of digital control technology. Because the effective control machine tool adopts servo motor and digital technology realizes the direct control of the working sequence and movement displacement of the parts executed by the machine tool, the transmission structure of traditional machine tool is cancelled or partially cancelled, so the mechanical structure also greatly simplifies the digital control, and requires the mechanical system to have high transmission rigidity and no transmission clearance To ensure the implementation of control instructions and the realization of control quality. At the same time, with the continuous improvement of computer level and control ability, it is possible to allow more functional parts to perform all kinds of auxiliary functions required at the same time on the same machine tool. Therefore, the mechanical cutting of CNC machine tool has higher integration function requirements than traditional machine tools. From the perspective of the requirements of manufacturing technology development, with the emergence of new materials and new processes, and the market competition for low cost requirements, metal cutting is developing towards the direction of higher cutting speed and precision, higher production efficiency and more reliable system. This requires that the CNC machine tools developed on the basis of traditional machine tools have higher precision, more driving power, better static and thermal stiffness of mechanical mechanism, more reliable work, and can achieve continuous operation and as little downtime as possible. The mechanical structure of the typical CNC milling machine is mainly composed of the basic parts, the main transmission system, the feed transmission system, the rotary table and other mechanical function accessories. The foundation of CNC milling machine is usually the structural parts of bed, column, beam, workbench and base. The size of the basic parts is large (commonly known as large piece), and the well constitutes the basic frame of the machine tool. Other components are attached to the base member, and some parts also need to move along the base member. Because the foundation plays a role of support and guidance, the requirements for the foundation are good stiffness

The importance of CNC machining spindle 1. The parameters of input starting point shall be reviewed in high-speed CNC processing. It is strictly forbidden to knock or impact the rotor end of spindle motor during operation. The operator is required to pay attention to the starting point of z-axis when aligning the tool to prevent misoperation. To avoid the impact and knife binding phenomenon in the operation process, the bearing of the spindle motor will be damaged. Once there is a phenomenon of knife binding, stop the machine immediately to prevent the bearing from causing more damage due to high-speed operation. Then, start running in from low speed, and the time is slightly longer than normal running in time, until the motor is running smoothly and normally before starting to work. 2. To ensure the motor cooling cycle system of the carving and milling machine works normally, before starting the machine. Then turn on the spindle motor, and it is strictly forbidden to use the spindle motor without cooling. The working environment temperature should not be higher than 30 ℃, when the ambient temperature is higher than 30 ℃, air conditioning shall be used, or forced cooling of the main shaft motor shall be performed by using a refrigerator. 3. The spindle motor of high speed CNC machining shall be preheated step by step according to the principle of running from low speed to high speed. When the motor reaches the required speed and the no-load operation is stable and the temperature is cooled, the machining can be carried out, so as to ensure the better machining accuracy. 4. When planning the cutter path, it is necessary to ensure the reasonable force on the spindle motor and carve according to the principle of knife provided by the technical service personnel. It is necessary to prevent vertical cutting, and it is strictly forbidden to overload the spindle motor, so as to ensure the normal service life of the spindle motor. 5. Generally, the spindle motor should be disassembled and reassembled for about one year, so as to ensure the bearing accuracy and extend the service life. In order to ensure the normal and good operation of the spindle motor, the assembly and assembly of the spindle motor must be carried out by experienced professional operators, in a clean environment and with appropriate tools. Do not knock it randomly. For the temporarily unused spindle, the residual water in the water chamber shall be blown out with compressed air, and the sleeve and shaft hole of shaft head shall be oil protected and put in a cool and dry place. 6. The high speed CNC processing water quality must be clean, and the cooling water of spindle motor uses pure water. In order to prevent the occurrence of microorganism and scale, water should be changed every seven days under normal conditions. When the surrounding environment is higher than 30 ℃ and there is no forced cooling measures, the purified water should be replaced once a day when the water temperature is the highest. In addition, operators should develop the habit of observing the water temperature during work, and change water when the water temperature exceeds 30 ℃

CNC milling machine programming

(l) Before writing or programming processing, the workpiece processing program should be prepared first. When the workpiece processing program is long and complex, it is better to program on the machine tool. When using the programming machine or computer programming sample to avoid occupying the machine, the short program should also be written on the program sheet

(2) Start the machine first and then turn on the machine. The system has the design of interlock. The power on of the machine tool is displayed on the CRT

(3) Back to the reference point for incremental control system (using incremental position detection element) machine tool, the first step must be taken to establish the coordinate moving datum of the machine tool

(4) According to the program storage medium (paper tape or magnetic tape, disk), the debugging program is input by paper tape reader, cassette tape machine, programming machine or serial port communication. If the simple program is directly input into CNC control panel by keyboard, if the program is very simple and only the workpiece program is not saved, it is necessary to use MDI mode to input and process segment by segment. In addition, the program uses workpiece origin, tool parameters, and so on Offset and various compensation must be input before processing

(5) If the program editing input program needs to be modified, the editing operation must be carried out. At this time, the mode selection switch is set to the editing position, and the edit key is used to add, delete and change. For the editing method, see the corresponding instructions

(6) Machine lock running program this step checks the program, if there is an error, you need to edit again

(7) The workpiece is loaded and the tool alignment and tool setting are continuously moved by manual incremental movement, or the tool starting point of the machine tool is moved to the start of the program and the tool reference is aligned

(8) Starting coordinate feed for continuous processing generally adopts memory program processing mode, which has lower failure rate than using program processing on paper tape. The feed speed is adjusted by feed rate switch. Press feed hold button to pause feed movement, observe processing condition or conduct manual measurement, and then press the cycle start button to resume processing, so as to ensure that the program is correct. Before processing, recheck the over milling It is more intuitive to use pencil instead of tool paper when machining plane curve workpiece. If the system has the function of tool path simulation, it can be used to check the correctness of the program

CNC manufacturers introduce the programming method of milling machine

1、 Programming method of NC milling machine

In order to learn NC milling machine programming well, we must understand the operation points of CNC milling machine. Most of the existing textbooks do not regard the operation and programming of CNC milling machine as a whole.

2、 Setting machine coordinate system of CNC milling machine

CNC milling machine manufacturers introduced CNC milling machine coordinate system determination method is similar to CNC lathe, but CNC milling machine has x, y, Z three axis. Confirm the machine coordinate system by returning to the mechanical zero point. After the machine is turned on, the worktable will return to the machine tool origin (or reference point, which is a point with a fixed distance from the origin of the machine tool). CNC milling machine return to zero, the steps are: the switch is placed in the “return to zero” position. Press the manual axis feed direction keys + X, + y, + Z until the return to zero indicator light is on. Setting the mechanical origin of machine tool is directly related to g54 instruction in programming.

3、 Setting workpiece coordinate system of CNC milling machine

Workpiece coordinate system is the coordinate system used in programming, also known as programming coordinate system. The coordinate system is artificially set. The establishment of workpiece coordinate system is an essential step before CNC milling machine processing. CNC milling machine establishes workpiece coordinate system by tool setting.

CNC mirror machining

The application of CNC mirror machining technology makes the metal surface roughness effect more ideal. For the mirror surface processed by CNC, its roughness is far less than 0.8um, which can reach 0.06, and the metal surface can reflect the image of the object more clearly. What’s more, the mirror machining efficiency of precision mold under the traditional technology is not high. The application of CNC mirror processing technology can effectively improve the processing efficiency of the mold. At the same time, CNC mirror processing technology can be used for mirror processing of raw materials of various materials, without too many limitations on the processing of raw materials. Although direct CNC mirror processing, the workpiece surface itself will always appear some knife marks, but in the later stage, there are subsequent processes of mold saving and polishing.

With time, when we are more proficient in the use of CNC mirror processing technology to cut metal, the surface roughness of machined parts will be lower, more in line with the desired finish, better applied to machinery. CNC lathe processing, is generally referred to in the CNC machine tool parts processing process. CNC machine tool is a kind of machine tool controlled by computer. The computer used to control the machine tool, whether it is a special computer or a general-purpose computer, is collectively referred to as the numerical control system. The motion and auxiliary action of NC machine tool are controlled by the instruction of NC system.

The instruction of CNC system is compiled by the programmer according to the material of the workpiece, processing requirements, characteristics of the machine tool and the instruction format (NC language or symbol) specified by the system. According to the program instruction, the CNC system sends operation or terminal information to the servo device and other functional components to control the various movements of the machine tool. When the processing program of the part is finished, the machine will stop automatically. Dongguan mold factory any kind of CNC machine tool, in its CNC system, if there is no input program instructions, CNC machine tools can not work.

The controlled actions of machining machine tools generally include the starting and stopping of the machine tool; the starting and stopping of the spindle, the change of rotation direction and speed; the direction, speed and mode of feed motion; the selection of cutting tools, the compensation of length and radius; the replacement of cutting tools, the start and close of coolant, etc.

At the beginning of CNC machine tool, aircraft parts with complex surface are selected as processing objects, which is the key to solve the problem of ordinary machining methods. The most important feature of NC machining is that the machine tool is controlled by perforated tape (or tape) for automatic processing.

Due to the different characteristics of aircraft, rocket and engine parts: the size of parts and components of aircraft and rocket is large and the profile is complex; the size of engine parts and components is small and the accuracy is high.

Therefore, the CNC machine tools used by aircraft, rocket manufacturing and engine manufacturing departments are different. In aircraft and rocket manufacturing, large-scale CNC milling machines with continuous control are mainly used, while in engine manufacturing, both continuous control CNC machine tools and point controlled CNC machine tools (such as CNC drilling machine, CNC boring machine, machining center, etc.) are used in engine manufacturing.

Computer gong processing acceptance

When engaged in precision machining, carefully do the following before work:

Carefully read the shift records to understand the operation and existing problems of the machine tool in the previous shift.
Check that the safety protection, brake (stop), limit and reversing devices are complete and in good condition.
Check the exposed guide rail surface, sliding surface, rotating surface and worktable of the machine tool. If there are tools, obstacles, impurities, oil stains and chips in the work center of computer gongs processing plant, they must be cleaned, wiped and oiled.
Check that the oil quantity of the oil storage part of the lubrication system meets the requirements and the sealing is good. The oil mark, oil window, oil cup, nozzle, oil line, felt, oil pipe and oil distributor shall be complete and in good condition and installed correctly. According to the performance requirements of lubrication diagram, carry out manual oil filling or motor-driven pump oiling, and check whether oil is coming from oil window in large gantry machining center.
Check whether there are new pulling, grinding and bumping on the working table, guide rail surface and main sliding surfaces of the machine tool. If any, inform the team leader or equipment personnel to check together and make records.
Check that the mechanical, hydraulic and pneumatic operators, such as C, valve, switch should be in the non working position.
Check that the electrical distribution box should be closed firmly and the electrical grounding is good.
If the machine tool is shut down for more than one shift, it shall run in idle for more than five minutes according to the operation procedures and requirements specified in the manual and the use of hydrostatic device.

1、 Acceptance requirements

Appearance inspection

(1) Check whether the finish of machined parts meets the drawing requirements.

(2) Check whether the surface of machined parts is damaged, rusted and bruised, and whether the thread shape and angle are correct.

(3) If the above problems are found, detailed records shall be made for future reference.

Quantity acceptance

(1) Based on the supply contract and processing voucher, check the material, specification and quantity of processed parts strictly against the drawings, and check them one by one.

(2) Make a record of quantity acceptance, indicating the place, time, participants, type, product name, quantity to be arrived and actually arrived.

Quality acceptance

(1) Assembly shall be carried out in strict accordance with the requirements and procedures of the general assembly drawing.

(2) Record carefully during quality acceptance. In case of quality problems of machined parts, the outsourcing processing unit shall be informed of the details in writing. Decide whether to return or replace according to the situation.

(3) In case of special requirements, the processing unit can be consulted for joint acceptance and assembly, and the acceptance documents can be signed after the installation is qualified.

2、 Acceptance procedure

After the processing parts of large mechanical parts are received, the full-time acceptance personnel shall be sent to check and accept the material, specification, model and quantity of the processed parts according to the requirements of the contract drawings.
The acceptance period is generally 1-2 days. The special situation depends on the effect of use. In case of quality problems, we can return the products to the processing unit, claim for compensation, and bear the economic losses of the processing unit.
Generally, the processing contract signed by the non production department will be directly accepted by the user department, and the acceptance report will be filled in.
If the unqualified parts are accepted by experience, the acceptance personnel must handle the maintenance and return procedures within the specified acceptance period.
For the acceptance of special precision machining parts, the full-time acceptance personnel shall organize relevant personnel for joint acceptance, and fill in the acceptance report in detail. For the unqualified parts, fill in the inspection form in detail. CNC machining is the condition to improve the machining accuracy and determine the selection direction of the parts outsourcing manufacturer in the future.

five axis linkage processing

Five axis linkage is the term of numerical control. Linkage means that the axis of CNC machine tool reaches a certain set point at a certain speed at the same time. Five axis linkage means that all five axes can be used. Five axis CNC machine tool is a kind of machine tool with high technology content and high precision, which is specially used for machining complex curved surface.

Five axis machine tools include vertical, horizontal and cradle type two axis NC table, NC table NC dividing head, NC table 90 axis, NC table 45B axis, NC table a axis, two axis NC spindle and so on. There are 7 kinds of five axis linkage modes in the above six categories. They all have their own characteristics. It is impossible to say which form is better, but what type of five axis machining is suitable for your products.

(1) Five axis linkage double turntable machine tool

(A) The rotation coordinate has enough travel range and good process performance

Five axis linkage 3

(B) The rigid part of the machine tool is much higher than that of the whole machine tool

(C) It is easy to develop into a machining center. It only needs to install independent tool magazine and tool changing manipulator. However, the coordinate driving power of the turntable of double turntable machine tool is large, and the coordinate conversion relationship is complex;

(2) Five axis linkage double swing head machine tool

The driving power of swing coordinate of double swing head machine tool is small, the loading and unloading of workpiece is convenient, and the relationship of coordinate transformation is simple

(3) Five axis linkage machine tool with one swing head and one turntable

The performance of a swing head and a rotary table type machine tool is between the above two

It can effectively avoid tool interference
For ruled surface parts, side milling can be used to form one tool
For general solid surface, especially for large flat surface, the end face of large diameter end milling cutter can be used for machining
It can carry out multi face and multi process processing for multiple space surfaces on the workpiece at one time
In five axis machining, the tool can be in the most effective cutting state relative to the workpiece surface. The error distribution on the part surface is uniform
In some cases, larger size tools can be used to avoid interference.

Current and future research focus of 5-axis CNC machining

The so-called line contact machining refers to the processing method of line contact forming in the process of machining, such as cylindrical peripheral milling, conical milling, camphor shaped hole cutting and abrasive belt grinding, etc. the characteristics of this processing method are: due to the high cutting speed at the cutting point, it can obtain higher machining accuracy, at the same time, due to the line contact molding, it has higher processing efficiency, and has developed to the corresponding task Research on line contact machining of Italian curved surface.

The use of five axis machine tool makes it easy to clamp the workpiece. No special fixture is needed in the process, which reduces the cost of the fixture, avoids multiple clamping and improves the machining accuracy of the die. Using five axis technology can reduce the number of fixtures. In addition, because the five axis machine tool can save many special tools in the processing, so the tool cost is reduced. Five axis machine tool can increase the effective cutting edge length, reduce the cutting force, improve the tool life and reduce the cost.

The use of five axis machine tool processing mold can quickly complete the mold processing, delivery, better guarantee the mold processing quality, make the mold processing easier, and make the mold modification easier. Ball end milling cutter is widely used in modern mold processing. The advantages of ball end milling cutter in mold processing are obvious. However, if the vertical machining center is used, the linear speed of the bottom surface is zero, so the bottom surface finish is very poor. If the four or five axis linkage machine tool processing technology is used to process the mold, the above shortcomings can be overcome.

Firstly, linear motor drive technology is used. The advantages of linear motor are linear drive, no drive chain, no wear, no reverse clearance, so it can achieve the best positioning accuracy. The linear motor has high dynamic performance, and the acceleration can exceed 2G. Linear motor drive also has the characteristics of high reliability and maintenance free.

The second is the use of dual drive technology. For the wide worktable or gantry type, if the middle drive is adopted, it can not guarantee that the driving force is in the center, which is easy to cause inclination and poor dynamic performance. Using double drive, double grating ruler and one driving module, the dynamic performance is perfect. A driver instruction, dual drive work at the same time, grating ruler to detect whether the two points are balanced, if not, through different instructions to achieve balance.

Machining center is generally divided into vertical machining center and horizontal machining center. The most effective machining surface of vertical machining center (three axis) is only the top surface of workpiece, and the horizontal machining center can only complete the four sides processing of workpiece with the help of rotary table. The high-grade machining center is developing towards the direction of five axis control. The five axis linkage machining center has the characteristics of high efficiency and high precision. The workpiece can be processed in one clamping. High grade CNC system can also be used for high precision machining of high-end space, such as automobile

Heat treatment of plastic mould

The main reason for the failure of plastic mold is due to improper heat treatment process, such as heating temperature, holding time, cooling speed and so on. Plastic mold in the process of processing, cracks or deformation, surface oxidation and decarburization phenomenon, is mainly because the mold failure.

First of all, on the impact of oxidation and decarburization, mainly because the mold quenching is stopped at high temperature, but can not be strictly controlled. In addition, after decarburization on the surface of the die, quenching cracks are caused due to the difference of microstructure between the inner and outer layers and the larger structure stress during cooling.

The second is about the rate of heating. Because the die steel contains more carbon and alloy elements and poor thermal conductivity, the heating speed should not be too fast and should be stopped slowly to avoid deformation and cracking of the die. In order to avoid oxidation and decarburization during heating and quenching in air furnace, the heating speed should not be too fast and the diathermy should be slow.

The above will not produce large thermal stress, relatively safe. If the heating speed of the mold is fast and the diathermy is fast, the thermal stress inside and outside the mold will be very large. If the control is not good, such as deformation or crack, it is very easy to occur, in the prevention, it is necessary to use preheating or slow down the heating rate.

Due to the large size of the worktable and die, it must be able to meet the requirements of large-scale worktable and die, In addition, small diameter end mills with large elongation are often used to process the mold cavity, so chatter is easy to occur in the processing process.

In order to ensure the machining accuracy and surface quality of parts, the high-speed universal milling machine manufactured by mould must have high dynamic and static stiffness to improve the positioning accuracy, tracking accuracy and anti vibration ability of the machine tool.

High speed and high-power high-speed machining is the development direction, high-speed milling has shown great advantages in mold processing. In order to adapt to the processing of the mold cavity surface, the radius of the tool should be less than the minimum radius of the cavity surface, so as to avoid “interference” between the tool and the workpiece. Because of the small diameter of the tool, the spindle speed is required to be very high. The main shaft speed of foreign high-speed machine tools has reached 40000-100000 R / min, and the rapid feed speed can reach 30000-60000 min. The rough and finish machining of the cavity and other parts of the mold parts is often completed in one-time clamping of the workpiece, so the spindle power should be high. The spindle power of the medium-sized mold milling machine and machining center is usually 10-40kw, some even higher.

The die cavity is composed of complex six curved surfaces and grooves, and many dies have deep cavity. In order to achieve high precision, high speed and high stability machining of 3D surface, the machine tool needs multi axis linkage, and has good comprehensive cutting ability of deep hole cavity. Five axis linkage machining center can be used, in addition to the linear motion of three coordinates, there are also two rotation coordinates of feed motion. The milling head or worktable can realize continuous rotary feed by multi axis linkage, so it is suitable for machining mold parts with complex cavity surface. It can be said that compound machining is one of the development directions of mold processing.

Processing center is written language, English Name: CNC machining center; computer gong is a common saying, more in Hong Kong, Taiwan and Guangdong. In this area, milling machines are called gongs when they are in the machining center, so milling machines are also called gongs, and computer gongs are also derived from this. Computer gongs, as the name implies, are gongs controlled by computers, so they are also called CNC milling machines. In fact, they are upgraded from CNC milling machines. The original principle is the same. The difference is that the machining centers use good materials with high precision, high speed and load The traditional CNC milling machine is half cover type, and most of the machining center has been changed to full cover type, which is more safe for processing and can effectively prevent the overflow of iron chips and the splashing of chips. Computer gong is an automatic machine tool equipped with program control system. The control system can process and decode the program with control code or other symbol instructions logically, so that the machine tool can move and process parts. Also known as CNC machining mold or CNC machine tools.

The computer gong can be divided into two parts, the body part and the system part.

Fuselage part:

1) Casting, which is the most important part of computer gongs, directly affects the accuracy, stability, wear resistance and the life of machine tools. After the casting is finished, it is not immediately used in production. A good casting is that it is subjected to wind and rain, sunlight exposure, natural weathering, and some of them are soaked in sea water. After the casting does not change, the machine tool is not easy to change and can maintain the stability and accuracy of the machine tool for a long time.

2) Spindle, the spindle is used to directly face the workpiece. It is driven by the motor to rotate at a high speed. If the tool holder is installed on the spindle, the workpiece can be cut to meet various production needs. The quality of the spindle will also directly affect the machining accuracy. If the internal bearing is worn, it will easily cause the spindle to swing, and the accuracy of the processed things will naturally have a deviation of several wires 。 At present, the speed of the spindle is generally around 8000 rpm, and the high-speed machine can achieve more than 20000 revolutions. Each machine has only one spindle.

3) Screw rod is also a machine

Accuracy of CNC cutting technology

The introduction of CNC cutting technology precision 1. Multiple cutting technology multi cutting technology is the fundamental means to improve the machining accuracy and surface quality of low-speed WEDM. It is a scientific integration of design and manufacturing technology, numerical control technology, intelligent technology, pulse power technology, precision transmission and control technology. Generally, through one-time cutting forming, secondary cutting to improve the accuracy, more than three times to improve the surface quality. In order to achieve high-quality surface, the number of times of cutting is as high as 7-9 times, but now it only needs 3-4 times. 2. The corner processing technology is constantly optimized and improved. Because of the lag of the electrode wire when cutting the corner, the corner will collapse. In order to improve the accuracy of corner cutting, researchers have adopted more dynamic corner processing strategies. Such as: change the wire path; change the processing speed (sheet); automatic adjustment of water pressure; control of processing energy. By using the integrated corner control strategy, the corner shape error can be reduced by 70% and the matching accuracy of 5 μ M can be achieved at one time. 3. High speed CNC adopts the technology of improving flatness. High precision finishing circuit is the technology of improving flatness, which is considered to be of great significance to thick workpiece processing. 4. The structure of the machine tool is more precise. In order to ensure high-precision machining, many technical measures are adopted to improve the accuracy of the host machine: ① control the temperature. Using water temperature cooling device, the temperature inside the machine tool is the same as the water temperature, and the thermal deformation of the machine tool is reduced. ② Linear motor is adopted. High response, precision positioning can achieve 0.1 μ m equivalent control, feed no vibration, no noise, improve discharge frequency, maintain stable discharge, twice cut ry5 μ M. ③ The thermal inertia of ceramic and polymer artificial granite is 25 times larger than that of cast iron, which reduces the influence of temperature change on cutting accuracy. ④ Fixed worktable and column moving structure are adopted to improve the bearing capacity of worktable, which is not affected by immersion processing and workpiece weight change. ⑤ Immersion machining is used to reduce the thermal deformation of the workpiece. ⑥ Motor servo, closed loop wire tension control. ⑦ High precision tool setting: using voltage modulation tool setting power supply. The tool setting accuracy can reach ± 0.005mm without damaging the workpiece, whether dry or wet. 5. In order to carry out the micro precision machining of small fillet, narrow slot, narrow slot and micro parts, high-speed CNC wire cutting technology is researched by many manufacturers. At present, the main manufacturing enterprises of EDM in the world can use 0.02-0.03mm electrode wire for cutting. Precision surface grinder is a common machine tool for machining. There are high requirements for the motion stability, commutation accuracy and commutation frequency. At present, the surface grinding machine is developing towards large-scale and high-speed, and the reciprocating speed of some surface grinding machines has reached 40% n []. Large high-speed surface grinder has a large inertia. When it changes direction, it will lead to a sharp rise in back pressure, resulting in reversing impact, which will have a disastrous impact on the machine tool. Therefore, the stability of reversing has become an important factor restricting the improvement of the working speed and machining accuracy of the grinder. The reversing mode and reversing control parameters in the system play a decisive role in reversing impact. The surface grinder adopts hydraulic transmission. It is urgent to design a new hydraulic reversing system. In this paper, the reversing impact of grinder is discussed from the perspective of commutation method and control strategy. 1. The mechanism of reversing impact is that in its hydraulic system, when the hydraulic transmission surface grinder changes direction. The valve port of the directional valve is closed instantaneously, and the oil circuit is suddenly disconnected, which makes the oil in the oil return chamber unable to drain. The larger m and V, we can see. The greater the kinetic energy, the greater the reversing impact. For the surface grinder with large inertia and high speed, its reversing impact is huge, which not only affects the machining accuracy of the machine tool, but also hinders the normal operation and service life. 1. Product analysis through product analysis should obtain certain composition information and some specific processing requirements. 2. Graphic design graphic design the graphic design should be based on the detailed analysis of the product, determine the type of graphics by analyzing the processing requirements, and draw through the graphics software. 3. Process planning is based on the analysis of the appearance and processing requirements of the workpiece products in the early stage, so as to reasonably establish each processing step from the overall processing situation. 4. In fact, the process of path generation is to realize the process planning through software, and optimize the tool path by setting parameters. 5. After the path simulation path is generated, we generally have no intuitive sense of its final performance on the machine tool. Here we can check the possible problems through path simulation, thus reducing the actual processing scrap rate. The general inspection focuses on the effect of workpiece appearance, whether it is overcut or undercut, and whether the process planning of the path is reasonable. 6. Path output path output is a necessary step for software design and programming to realize on the machine tool. Through the path output, the relationship between the two can be established by the intermediate reference. If you have a professional background in CNC, it can also be understood as the post-processing of tool path.

New energy development

In China, the amount of conventional energy resources is only 60% of the world average level. In order to meet the growing energy demand, it is necessary to accelerate the development and utilization of new energy. At present, the 9% share of new energy in the energy structure is relatively low compared with the developed countries in the world, and there is still a lot of room for development.

Although the latest statistics of 2008 have not been released yet, the proportion of China’s new energy production in the overall energy structure will exceed 9% based on the data from various aspects, especially the growth rate of China’s new energy production and consumption in the past 10 years.

2008 is an extraordinary year for China’s energy work. Affected by the changes of the world macro-economic situation and natural disasters, the supply and demand of energy has experienced a roller coaster like operation from “tight supply” at the beginning of the year to “demand slowing down” at the end of the year. Authoritative experts pointed out that the easing of the tense situation of energy supply and demand does not mean that China’s energy demand has dropped significantly, nor does it mean that China’s energy supply can achieve absolute self-sufficiency. Therefore, the task of developing new energy is still urgent. Compared with the level of developed countries, 9% of new energy in China is still at a relatively low level.

In 2007, China produced 2.35 billion tons of standard coal, of which coal accounted for 76.6%, oil accounted for 11.3%, natural gas accounted for 3.9%, and other unconventional energy accounted for 8.2%; while the total energy consumption in this year was 2.66 billion tons of standard coal, including 69.5% of coal, 19.7% of oil, 3.5% of natural gas and 7.3% of unconventional energy. In terms of total amount, there is still a gap in energy consumption in China. From the structural analysis, in China’s energy structure, the dominant position of coal has not changed. Although the development speed of new energy is fast, its proportion is still too small.

China has a long way to go in developing new energy, whether in terms of structure or total demand. First of all, the development of new energy is an effective guarantee to maintain rapid economic growth. From 2003 to 2008, the average annual growth rate of China’s GDP is close to 10%. In order to maintain the stable and sustainable development of economy, we must have strong energy guarantee. Throughout China’s resource reserves, the total amount is large and the per capita share is small, so it is difficult to form a sustainable support only relying on traditional energy.

Secondly, the development of new energy is an effective way to alleviate environmental pressure. Compared with traditional energy, new energy has the characteristics of less pollution and high efficiency. Vigorously developing new energy will help to reduce economic losses caused by environmental damage and achieve the goals set in the eleventh five year plan.

Third, the development of new energy is an effective means to ensure the safe supply of energy. Energy security is an important part of a country’s economic security and an important barrier to ensure the independent and healthy development of a country’s economy. At present, China has to import a part of its oil every year, and its dependence on foreign countries is relatively high. To ensure the safe supply of energy, we must adhere to the diversified strategy, and vigorously developing new energy is the concrete embodiment of this strategy.

Fourth, the development of new energy is a powerful weapon to solve the dilemma of unbalanced regional development in China. There is a big gap among regions in China, which is unfavorable to the sustainable development of economy and society. The development of new energy in the vast western regions and remote rural areas not only improves people’s livelihood, but also promotes economic development.

Fifth, it is feasible to develop new energy. With the improvement of technical level, the cost of new energy development has dropped sharply, and the cost of some new energy has been close to or even lower than that of conventional energy.

The reporter interviewed the national energy administration and relevant people in the industry. The unanimous judgment is that the development trend of China’s new energy will, on the whole, maintain a sustained and rapid development momentum and have a bright future.

From the perspective of policy environment, the recently concluded energy work conference has determined the work direction with the theme of structural transformation, which indicates the arrival of a new era of new energy industry. Both the promulgation of new energy and renewable energy planning and the implementation of the new energy law in the future have brought unprecedented opportunities for the development of new energy.

From the perspective of investment, international capital is optimistic. Even in the context of the international financial crisis, investment in the field of new energy will still become the hot spot of capital pursuit. Under the influence of policy guidance, domestic capital will follow suit one after another. The continuous rise of new energy sector in A-share market is sufficient evidence.

From the perspective of the internal structure of new energy, the priority development direction in the future is still wind energy, solar energy and nuclear energy with high technology maturity and economic feasibility. Economic feasibility is an important bottleneck restricting the development of new energy, which will be solved gradually with the improvement of China’s technical level.

High speed computer gong processing feeder

The basic knowledge of high speed computer gong processing feeding mechanism

Auxiliary device computer gong processing index control feed machine some necessary supporting parts, to ensure the operation of CNC feeder, such as cooling, chip removal, lubrication, lighting, monitoring, etc. It includes hydraulic and pneumatic devices, chip removal device, exchange table, CNC turntable and CNC dividing head, as well as cutting tools and monitoring and detecting devices.
Driving device high speed Gong machining is the driving part of the executive mechanism of NC feeding machine, including spindle drive unit, feed unit, spindle motor and feed motor. Under the control of the electric servo system or hydraulic control of the spindle. When several feed linkage, positioning, straight line, plane curve and space curve processing can be completed.
The main machine is the main body of CNC feeding machine, including body, column, spindle, feed mechanism and other mechanical parts. It is a mechanical part used to complete various cutting processes. Programming and other auxiliary equipment: it can be used to program and store parts outside the machine.
High speed Gong machining of CNC device is the core of NC feeding machine, including hardware (printed circuit board, CRT display, key box, paper tape reader, etc.) and corresponding software, which are used to input digital part program, complete input information storage, data transformation, interpolation calculation and realize various control functions. Basic requirements of large CNC machining system
In the process of large CNC machining, the worktable may require forward or reverse operation at any time according to the shape of machining track. CNC lathe machining center prompts you to consider the conversion of electrical energy and mechanical energy between starting and braking during forward and reverse operation, so as to realize rapid braking.
In order to adapt to different processing conditions, servo has a wide range of speed regulation and excellent speed control characteristics.
High rigidity and high speed stability servo for large CNC machining should keep the feed rate constant under different load conditions or when the cutting conditions change, which requires the servo to have excellent static and dynamic load characteristics.

In order to ensure the contour cutting shape accuracy and low surface roughness of the machined surface, the servo should have good fast response characteristics and no overshoot.

High precision in order to meet the machining accuracy, it is necessary to ensure the positioning accuracy and feed accuracy of the machine tool, that is to say, the servo should have high static resolution, and the dynamic characteristics should be at least a first-order error free system.
Large CNC machining low speed and high torque, the characteristics of machine tool processing is cutting at low speed, the feed drive should ensure rated torque output at low speed, that is to say, servo should have constant torque output.

Function debugging of high speed computer gong machine tool accuracy

High speed computer gongs use precision level instrument and other detection tools, mainly by adjusting the pad iron way to fine adjust the level of the main bed of the machine tool, so that the geometric accuracy of the machine tool can reach the allowable tolerance range;
For the automatic tool change device, adjust the position of the tool magazine, manipulator, travel parameters, etc., and then check the action with the command, which is required to be accurate;
For the machine tool with APC automatic exchange table, after adjusting the relative position, carry out automatic load exchange;
After the adjustment of the machine tool, carefully check whether the parameter setting values in the numerical control system and the programmable controller conform to the data specified in the random index, and then test the main operation functions, safety measures, execution of common instructions, etc.
Mold processing to check the machine tool auxiliary function and accessories normal work. It is usually composed of CNC system, main drive system, feed servo system, cooling smooth system and so on. 1. The spindle box contains the spindle box and spindle drive system, which is used to clamp and rotate the cutter. The spindle speed scale and output torque have a direct impact on the machining. 2. The feed servo system is composed of feed motor and feed actuator. According to the feed rate set by the program, the relative motion between the tool and the workpiece is completed, including linear feed motion and rotary motion. 3. Control system CNC milling machine motion control in the middle of the implementation of NC machining program control machine tools for processing. 4. Auxiliary equipment such as hydraulic, pneumatic, smooth, cooling system and chip removal, protection and other equipment. 5. The base parts of high-speed computer gong machine tools usually refer to the base, column, beam, etc., which are the foundation and structure of the whole machine tool. Die making technology of extrusion die for high speed CNC machining of aluminum profile 1. Due to the bad working conditions of aluminum alloy extrusion tools and dies, high temperature, high pressure and high friction are required in high-speed CNC machining. Therefore, high-strength heat-resistant alloy steel is required. The melting, casting, forging, heat treatment, electrical machining, mechanical processing and surface treatment of these steels are very complex, which brings about the development of die and mold A series of difficulties. 2. In order to improve the service life of tools and moulds and ensure the surface quality of products, it is required that the roughness of the working belt of the die cavity should reach 0.8-0.4 μ m, and the roughness of the die plane should be less than 1.6 μ M. therefore, special polishing process and polishing equipment should be adopted when making the mold. 3. Due to the development of extrusion products in the direction of high precision and sharp, the wall thickness requirement of some profiles and pipes is reduced to about 0.5mm, and the tolerance of extruded products is required to reach ± 0.05mm. In order to extrude such ultra-high precision products, the manufacturing accuracy of dies is required to reach 0.01mm

Wheeled Construction Machinery

The fuel consumption of Wheeled Construction machinery is one of the major construction costs. Therefore, the fuel oil with freezing point 3-5 ℃ lower than the minimum temperature should be selected according to the temperature of the construction area. The fuel saving measures for construction transport vehicles and engines are as follows:

(1) Try to reduce the weight of the vehicle. Increasing vehicle weight will increase fuel consumption correspondingly. Therefore, unnecessary additional equipment should be removed from the vehicle during construction without affecting the project quality

(2) The resistance to acceleration and fuel consumption should be reduced as much as possible.

In construction, if the speed is below 400km / h, the air resistance can be ignored. It should be noted that the rolling resistance. When the vehicle is driving on an uneven road surface, the deformation of suspension device and tire increases due to its frequent jumping, resulting in a large increase in rolling resistance. Compared with the situation of driving on good road surface, the fuel consumption increases by 30% – 50%. Therefore, it is necessary to repair and maintain the construction access road. At the same time, the tire pressure has a great influence on the rolling resistance. If the tire pressure is reduced on the hard road surface, the tire deformation will be large and the rolling resistance will be increased; if the tire pressure is reduced on the soft road surface, the contact area between the tire and the ground will increase, and the pressure per unit area will decrease, which will reduce the rolling resistance. Therefore, it is necessary to pay attention to the changes of road conditions in construction and select appropriate tire pressure to reduce fuel consumption.

The transmission ratio of each gear of vehicle transmission has a great influence on fuel consumption. The high-speed gear with small transmission ratio should be selected as far as possible in construction, so as to save fuel.

(3) Increase the engine compression ratio to the standard value. The compression ratio of diesel engine is generally between 16 and 22. With the increase of compression ratio, the temperature and pressure at the end of compression are increased, which is beneficial to the combustion and expansion of the mixture, the thermal efficiency of the engine is improved, the effective power is increased and the fuel consumption is reduced. The specific measures are as follows:

Reduce the resistance of the intake system. The filter should be cleaned and maintained in time to ensure that there is enough air to enter the cylinder in time.

Keep the vehicle in good condition. For the engine cylinder pressure, the general diesel engine should not be less than 20% of the original engine standard pressure, gasoline engine is not less than 30%. For the pressure difference between each cylinder, the diesel engine is generally required to be no more than 8%, and the gasoline engine is not more than 10%. If the cylinder pressure does not reach the specified standard, grind the valve and replace the piston ring as required. It should also be noted that the carbon deposit in the combustion chamber will make the compression ratio increase automatically. If the compression ratio is too high and the carbon deposit is too high, it is easy to cause the cylinder deflagration and increase the fuel consumption. Therefore, it is very necessary to remove the carbon deposit. In addition, the clearance between the inlet and exhaust valves must be adjusted to the specified value, because the fuel consumption will be increased if the clearance is too large or too small.

(4) Good engine fuel supply angle in advance. If the fuel supply advance angle is too large or too small, the fuel consumption of the engine will increase. Therefore, in order to make the engine have good performance, the fuel supply advance angle must be calibrated.

(5) Reduce fuel consumption per unit load. If the vehicle condition permits, the productivity can be increased and the fuel consumption per unit weight can be significantly reduced by increasing the vehicle load to the rated load.

(6) Master the economic speed. In construction, the roads are generally informal roads, that is, access roads. In this case, the correct relationship between safety, fuel consumption and vehicle speed should be grasped. Taking the half load of Tatra T815 as an example, the relationship between fuel consumption and vehicle speed is: when the vehicle speed is 25-30km / h, the fuel consumption is the least, that is, in the construction, this speed can not only ensure the production efficiency, but also be economical and reasonable.

(7) Choose lubricating oil correctly. The selection of lubricating oil is the key factor to reduce power consumption and fuel consumption. Different specifications and brands of lubricating oil should be selected in winter and summer.

First of all, strictly abide by the tire inflation standards, check whether the ministries and commissions have air leakage after inflation, and regularly check the tire pressure to ensure compliance with the standards. Develop the habit of using a barometer to measure air pressure. Do not judge with naked eyes. Ensure that the tire has a certain elasticity, when bearing the specified load, make its deformation not exceed the specified range, and ensure the vehicle has good stability and comfort in driving. The pressure of the spare tire should be higher to avoid running away for a long time.

Secondly, it is necessary to select and install the tire correctly, and use the corresponding inner tube according to the tire specification. Tires assembled on the same machine shall be of the same brand, structure and performance. If this is not possible, tyres of the same brand, specification, pattern and type should be assembled on the same axle; when replacing new tires, the whole vehicle or coaxial should be changed at the same time; tires with directional patterns should be installed in accordance with the specified rolling direction; when replacing new tires, the new tires should be installed on the front wheels, and the repaired tires should be installed on the rear wheels. In order to ensure driving safety, the retreaded tires are not allowed to be used as steering wheels (front wheels).

Third, regular tire rotation. After the vehicle has been running for a period of time, the front and rear tires are different in terms of fatigue and wear. Therefore, it is necessary to change the position in time according to the regulations. There are two ways to change tires: cross method and cycle method. The cross transposition method is suitable for the vehicles which often drive on the road with greater camber, while the cyclic transposition method is suitable for the vehicles that often drive on the flat road.

Fourth, it is also necessary to control the temperature of the tire. In the process of driving, the tire will generate heat due to friction and deformation, which will increase the temperature and pressure inside the tire. When the temperature of the tire is very high, we can’t use the method of deflating and depressurizing, and we can’t pour water on the tire to reduce the temperature, so as to avoid accelerating the damage of the tire. Should be in