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In this era of rapid development, the use of mechanical equipment processing, CNC processing, has been very common, but to achieve the quality, or accuracy, or the details of the processing, or the level of operators, many people will have doubts, what are these CNC, in fact, CNC, which we often say processing center, plays an increasingly important role in modern furniture production The more important the position is, you can say that it is the “production line standard configuration”, or you can think of it as a “necessary good tool”.

CNC processing, CNC processing economy will be affected by what factors

What principle should the arrangement of processing sequence follow? The arrangement of machining sequence should be considered according to the structure and blank condition of the parts, as well as the need of positioning and clamping. The key point is that the rigidity of the workpiece will not be damaged. Generally, the sequence should be carried out according to the following principles:

① The processing of the previous process cannot affect the positioning and clamping of the next process, and the machining process of general machine tool should be considered comprehensively.

② The inner shape and inner cavity processing sequence is carried out first, and then the contour processing process is carried out.

③ In order to reduce the times of repeated positioning, tool changing and pressing plate moving, it is better to connect the processes with the same positioning, clamping mode or the same tool.

④ For multiple procedures in the same installation, the process with less damage to the rigidity of the workpiece should be arranged first.

How to determine the tool setting point is reasonable? The tool setting point can be set on the part to be processed, but the tool setting point must be the reference position or the position that has been finished. Sometimes the tool setting point is damaged after the first process, which will lead to the second process and subsequent tool setting point can not be found. Therefore, in the first process of tool setting, it is necessary to set up a relative tool setting position where there is a relatively fixed dimension relationship with the positioning datum, so that the original tool setting point can be retrieved according to the relative position relationship between them. This relative tool setting position is usually set on the machine tool table or fixture, and the selection principle is as follows:

① Easy to find

② Programming is convenient

③ Small tool setting error

④ Inspection during processing

Self inspection content:

1. Stretching must be carried out on the drawing frame after the aluminum alloy profile is cooled to below 50 degrees. If the temperature is too high, the drawing will not only damage the human body and the wool top, but also cause twists and turns, twisting, poor function and other absolute waste products before and after aging due to the failure to completely eliminate the internal stress of aluminum alloy profiles.
2. The control of stretching amount is controlled at 1%, and it should be noted that if the stretching amount is too high, the scale error of head, middle and tail will occur, and the appearance of water ripple like twist (fish scale) mark, low elongation, high hardness and brittle (low plasticity). If the tensile strength is too low, the compressive strength and hardness of the profile will be low, even aging (quenching) can not improve the hardness, and the profile is easy to curve (commonly known as big knife bend).
3. In order to control the tensile deformation and the scale change of the whole profile, appropriate special clamp pad and appropriate method should be selected. In particular, the opening material, arc material, cantilever material, as well as the bending shape of the profile should pay more attention to the reasonable and useful use of stretch clamp pad.
4. Pay attention to the stress conditions of small feet, thin teeth, long legs, arc surface, inclined surface, opening and viewpoint of profiles with high width thickness ratio, long cantilever wall, large radian, great wall thickness difference and strange shape, so as to avoid the defects such as deformation, twisting and spiral of section or point scale.
5. Due to the heat blocking effect of wool top, the aluminum profiles with high demand for decorative appearance must be turned up and down, back and forth, so as to facilitate uniform heat dissipation and reduce the transverse bright spot defects caused by uneven heat dissipation and different crystallinity. Especially for aluminum profiles with large width and thick wall, more attention should be paid to them.
6. In the process of reclaiming, moving and stretching, it is not allowed to touch, pull, stack, jam and entangle with each other, and a certain space shall be reserved between them. The aluminum alloy profiles with easy twists and turns and the length of discharge shall be disposed in time, and the maintenance and disposal between them shall be done when necessary.

Self test range:

1. Before processing, the processor must clearly see the content of the process card, clearly know the parts, shapes and dimensions of the workpiece to be processed, and know the processing content of the next process.
2. Before clamping the workpiece, the blank size should be measured to see if it meets the requirements of the drawing, and the placement of the workpiece must be carefully checked whether it is consistent with the programming operation instruction.
3. Self inspection should be carried out in time after rough machining, so as to adjust the data with errors in time. The self inspection content mainly includes the position and size of the processing parts. 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 drawing requirements;

(4) The position and size between the processing parts. After checking the position and size, measure the rough machined shape ruler (except arc).

1. After rough machining self inspection, finish machining is carried out. After finishing, the workers should check the shape and size of the processing parts: check the basic length and width of the vertical processing parts; measure the base point size marked on the drawing for the processing parts of the inclined plane.
2. The worker can remove the workpiece and send it to the inspector for special inspection after completing the self inspection of the workpiece and confirming that it meets the drawing and process requirements.

Computer gong processing route:

(1) the shortest cutting feed route. The cutting feed path is the shortest, which can effectively improve the production efficiency and reduce the tool loss. When arranging the shortest cutting feed route, the rigidity of the workpiece and processing technology should be ensured.

(2) the shortest empty route.

① Use the starting point skillfully. A general example of rough turning with rectangular circulation. The setting of tool setting point a takes into account the need for convenient tool change in the process of finishing turning, so it is set far away from the blank, and at the same time, the tool starting point and tool setting point are overlapped together

② Skillfully set up tool changing point. In order to consider the convenience and safety of tool change, sometimes the tool change point is also set far away from the blank. Then, when the second tool is replaced, the empty travel route of finishing turning must be longer; if the tool change point of the second tool is also set at the no point position in the middle, the empty travel distance can be shortened.

③ The route of “returning to zero” should be arranged reasonably. In order to simplify the calculation process and facilitate the verification, the programmer sometimes returns the end point of each tool to the position of tool setting point by executing the “return to zero” operation command, and then execute the subsequent program. This will increase the distance of the feed path and reduce the production efficiency. Therefore, in order to meet the requirement of the shortest feed path, the distance between the end point of the previous cutter and the starting point of the next cutter should be as short as possible or zero when arranging the “return to zero” route reasonably. In addition, when selecting the command to return to the tool point, on the premise of no interference, the direction of “return to zero” in both directions of x-axis and z-axis is adopted as far as possible, and the “return to zero” route of this function is the shortest.

(3) step cutting feed route of large surplus blank. Two kinds of cutting feed routes of too much stock are listed. It is the wrong step cutting route. Cutting in the order of one bucket and five times is the correct step cutting feed route. Because in the same amount of back knife.

(4) the continuous cutting feed route of the part contour finishing. One or several finishing operations can be arranged for the finish machining of part contour. The finished contour shall be machined continuously by the last tool. At this time, the advance and retreat position of the tool shall be selected appropriately. It is not necessary to arrange cutting, cutting out, tool changing and stopping in the continuous contour, so as to avoid damaging the balance state of the process system due to the sudden change of cutting force, resulting in scratches on the part contour Injuries, abrupt changes in shape or retention of knife marks.

(5) special feeding route. In the NC turning process, in general. The longitudinal feed of the tool is along the negative direction of the coordinate, but sometimes it is not reasonable to arrange the feed path according to the conventional negative direction. It may even damage the workpiece.

2、 Advantages of computer gong processing:

① A large number of tooling is reduced, and complex tooling is not needed to process parts with complex shapes. If you want to change the shape and size of parts, you only need to modify the part processing program, which is suitable for the development and modification of new products.

② The machining quality is stable, the machining precision is high, and the repetition precision is high, which can meet the processing requirements of aircraft.

③ In the case of multi variety and small batch production, the production efficiency is higher, the time of production preparation, machine tool adjustment and process inspection can be reduced, and the cutting time is reduced due to the use of the best cutting amount.

④ It can machine complex surface which is difficult to process by conventional method, and even can process some parts which cannot be observed. The disadvantage of NC machining is the high cost of machine tools, which requires maintenance personnel to have a high level.

1. The oxide scale of the parts shall be removed. There shall be no scratch, scratch and other defects on the surface of the parts, and the burr and flash shall be removed;
2. After quenching and tempering, high frequency quenching, tempering at 350-370 ℃, hrc40-45, carburizing depth 0.3mm, and aging treatment at high temperature.
3. The undeclared shape tolerance shall meet the requirements of gb1184-80, the allowable deviation of undeclared length dimension shall be ± 0.5mm, and the casting tolerance zone shall be symmetrical to the basic dimension configuration of blank casting;
4. The undeclared fillet radius is R5 and the undeclared chamfer is 2 × 45 ° and the acute angle is blunt;
5. The temperature shall not exceed 100 ℃. After the gear is assembled, the contact spot and side clearance of the tooth surface shall meet the provisions of GB10095 and gb11365;
6. When assembling the hydraulic system, it is allowed to use sealing filler or sealant, but it should be prevented from entering the system. Parts and components (including purchased parts and outsourcing parts) entering the assembly must have the certificate of inspection department before assembly.

At present, the level of precision and metal precision machining technology is one of the important symbols of a country’s manufacturing industry level. Computer gong processing, Dongguan high speed computer gong processing, Dongguan mold processing, Dongguan Mechanical parts processing, CNC precision machining can achieve the accuracy, surface roughness, processing size range and geometry shape are important symbols of a country’s manufacturing technology level – precision and metal precision machining technology has become the key technology to achieve success in International competition. The development of cutting-edge technology, the development of national defense industry, the development of microelectronics industry, etc., all need precision and special processing technology to manufacture relevant instruments and equipment.

The precision of metal precision machining is more than one order of magnitude higher than the traditional precision machining. In addition to the need for new processing methods or new processing mechanisms, there are special requirements for workpiece material, processing equipment, tools, measurement and environmental conditions. The material of the workpiece must be extremely fine and uniform, and properly disposed to eliminate the internal residual stress, ensure the dimensional stability of the height, and prevent deformation after processing. The precision machining equipment should have high motion accuracy, the straightness of guide rail and the rotation accuracy of spindle should reach 0.1 micron level, and the micro feed and positioning accuracy should reach 0.01 micron level.

In the production process of precision parts, the process of directly changing the shape, size and performance of raw materials (or blanks) into finished products is called technological process. The main part of the production process. For example, casting, forging and welding of blank, heat treatment of changing data performance, machining of parts, etc. all belong to technological process. In order to pass the process, the process of cutting out the thickness of the parts is also called the process of cutting out the thickness of the parts.

In the precision machining of titanium alloy parts, many factors have an impact on the surface processing quality. Computer gong processing, Dongguan high-speed computer gong processing, Dongguan mold processing, Dongguan Mechanical parts processing, CNC processing, such as the geometric parameters of cutting tools, spindle rotation accuracy, slide motion accuracy, natural vibration and vibration isolation, system stability, etc. These factors themselves have certain regularity, and these regular influencing factors have an impact on the surface processing quality with their inherent rules. In order to achieve ultra precision turning, it is necessary to optimize the cutting parameters, so it is necessary to predict the surface roughness to be obtained. Computer gong machining, Dongguan high-speed computer gong machining, Dongguan mould processing, Dongguan Mechanical parts processing, CNC machining, through the research on the model theory of influencing factors of external surface roughness, we can further study the machine tool, unit parts, cutting tools, cutting mechanism and cutting technology. There are many factors affecting the surface quality of machining, such as cutting performance of additive material, motion precision of spindle, motion precision of slide plate, natural vibration and vibration isolation, tool and cooling, cutting parameters and environmental conditions.

1. Feasibility analysis of high-speed CNC machining technology: it mainly aims at the transformation target and processing object, and makes a comprehensive analysis on the structure, performance and accuracy of the transformed machine tool, including whether the original structural design of the machine tool is reasonable, whether the basic components and structural parts of the machine tool are still in good condition, and whether the ordinary machine tool is changed into a numerical control machine tool, It is necessary to investigate whether the mechanical transmission structure of each coordinate axis and the form of guide rail pair are applicable; whether there is a gap between the current accuracy of the measuring machine tool and that of the factory.
2. Economic feasibility analysis of high-speed CNC machining: Based on the actual operability, the paper lists several situations that should be considered: considering the value of the machine tool, analyzing whether the input required to achieve the transformation goal is too high; analyzing the transformation value from the position and importance of the machine tool in the unit’s product manufacturing; estimating whether the investment can be recovered quickly from the input-output rate of the machine tool, And then it can produce better benefits quickly.
3. It is a key problem for high-speed CNC machining to choose the machine tool reformer. If it is well chosen, the transformation task can be successfully completed and the transformation goal can be achieved; if the selection is not good, it is not only the failure of machine tool transformation, but also a waste of money and time, affecting production. Installation and adjustment of high speed CNC ball screw nut

High speed CNC ball screw nut pair is only used to bear axial load. Radial force and bending moment will cause additional surface contact stress and other adverse loads on the ball screw pair, which may cause permanent damage to the ball screw. Therefore, when the ball screw nut pair is installed on the machine tool, attention should be paid to: 1. The high-speed CNC ball nut should move within the effective stroke, and the limit must be set at both ends of the stroke, so as to avoid the nut out of the lead screw shaft and cause the ball to fall off. 2. Due to the high transmission efficiency of the ball screw nut pair, it is not self-locking. When it is used for vertical transmission, if the weight of the components is not balanced, the reverse transmission caused by the dead weight of the components after the transmission stops or the motor loses power must be prevented. The methods to prevent reverse transmission can be worm gear drive, electric brake, etc.

1. The axis of the high-speed CNC screw must be parallel to the axis of the supporting guide. The center of the bearing seat at both ends of the machine tool and the center of the nut seat must form a line at three points.
2. When the ball screw nut pair is installed on the machine tool, do not remove the nut from the screw shaft. If it must be removed, use the auxiliary sleeve, otherwise the ball may fall off during loading and unloading.
3. When the nut is installed into the mounting hole of the nut seat, the impact and eccentricity should be avoided.
4. In order to prevent chip from entering and wearing the nut pair of ball screw, high-speed CNC can install protective devices such as wrinkle protection cover and spiral steel belt protection sleeve to protect the screw shaft completely. In addition, dust ring can be added at both ends of screw nut when there is much floating dust.

Basic characteristics of large iron plate processing

1. Large scale iron plate processing precision requirements, a pair of die is generally composed of a female die, a punch and a mold base, some may also be a multi piece assembly module. Therefore, the combination of upper and lower dies, the combination of inserts and cavities, and the assembly of modules all require high machining accuracy. The dimensional accuracy of precision die is often up to μ m level.
2. The shape and surface of some products, such as automobile panels, aircraft parts, toys and household appliances, are composed of a variety of curved surfaces, so the mold cavity surface is very complex. Some surfaces have to be treated mathematically.
3. The production of small batch mould is not mass production, in many cases, only one set is produced.
4. There are many working procedures for large-scale iron plate processing, such as milling, boring, drilling, reaming and tapping.
5. The use of repeated production mould has life. When the use of a pair of dies exceeds its service life, it is necessary to replace a new mold, so the production of mold is often repetitive.
6. Sometimes there are no drawings or data in the production of profiling mould, and the profiling processing should be carried out according to the actual object. This requires high precision and no deformation.
7. The die material for large-scale iron plate processing is excellent, and the hardness is high. The main material of the mold is made of high-quality alloy steel, especially the mold with high life. This kind of steel has strict requirements from blank forging, processing to heat treatment. Therefore, the preparation of processing technology can not be ignored, heat treatment deformation is also a serious problem in processing.

The basic knowledge of high speed computer gong processing feeding mechanism

1. Auxiliary device

Computer gong processing index control feed machine some necessary components, to ensure the operation of CNC feeder, such as cooling, chip removal, lubrication, lighting, monitoring and so on. 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.

1. Driving device

Gong machining is the driving part of the executive mechanism of CNC feeding machine, including spindle drive unit, feed unit, spindle motor and feed motor. Under the control of the numerical control device, he realizes the spindle and feed drive through the electric or electro-hydraulic servo system. When several feed linkage, positioning, straight line, plane curve and space curve processing can be completed.

1. Host computer

It is the main body of CNC feeder, including body, column, spindle, feed mechanism and other mechanical components. 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.

1. Numerical control device

High speed computer gong machining is the core of CNC feeding machine, including hardware (printed circuit board, CRT display, key box, paper tape reader, etc.) and corresponding software, which is used to input digital parts program, complete input information storage, data transformation, interpolation calculation and realize various control functions.

1. 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. Dongguan mold processing 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.
2. In order to adapt to different processing conditions, servo has a wide range of speed regulation and excellent speed control characteristics.
3. High rigidity and high speed stability servo for large CNC machining should keep the feed speed constant under different load conditions or when cutting conditions change. Dongguan machine parts machining requires servo to have excellent static and dynamic load characteristics.
4. Fast response and no overshoot. 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.
5. 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.
6. 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.

1. Three basic requirements for selecting datum: (1) the selected datum should be able to ensure accurate positioning of workpiece, convenient and reliable loading and unloading. (2) The size calculation of the selected datum and each processing part is simple. (3) Ensure the machining accuracy.

(2) the positioning accuracy of the workpiece should be controlled strictly when the fixture is installed; (2) the positioning accuracy of all parts should be controlled strictly when the fixture is installed; (4) the positioning accuracy of all parts should be controlled strictly when the fixture is installed The selected datum should ensure the completion of as many processing contents as possible; (5) during batch processing, the part positioning datum should coincide with the tool setting datum of workpiece coordinate system as much as possible; (6) when multiple clamping is needed, the datum should be unified before and after.

Determination of fixture for machining center:

1. The basic requirements of the fixture: (1) the clamping mechanism shall not affect the feed, and the processing part shall be open; (2) the fixture can be installed in the machine tool in a directional way; (3) the rigidity and stability of the fixture shall be good.
2. Types of commonly used fixtures: (1) general fixture: such as vise, dividing head, chuck, etc.; (2) modular fixture: modular fixture is composed of a set of universal components with standardized structure and dimension; (3) special fixture: fixture specially designed and manufactured for one or several similar processing items; (4) modular fixture Adjustable fixture: the combination of modular fixture and special fixture can not only ensure the accuracy of processing, but also make clamping more flexible; (5) multi position fixture: the fixture that can clamp multiple workpieces at the same time; (6) Group Fixture: it is specially used for clamping workpieces with similar shape, size and positioning, clamping and processing methods.

The selection principle of machining center: 3

(1) On the premise of ensuring the machining accuracy and production efficiency, the general fixture is preferred;

(2) Simple special fixture can be considered for batch processing;

(3) Multi position fixture and high efficiency special fixture such as air pressure and hydraulic pressure can be considered for mass processing;

(4) Group fixture should be used when group process is adopted;

1. The best clamping position of the workpiece on the machine tool table: the clamping position of the workpiece should ensure that the workpiece is within the processing stroke range of each axis of the machine tool, and make the length of the tool as short as possible, so as to improve the processing rigidity of the tool.

1、 Pause instruction

G04X（U）_ /P_ It refers to the tool pause time (feed stop, spindle does not stop), the value after address P or X is the pause time. The value after X should have a decimal point. Otherwise, it should be calculated by one thousandth of this value in seconds (s). The value after P cannot have a decimal point (i.e., an integer), and the unit is Ms.

For example, G04 x2.0; or G04 X2000; pause for 2 seconds

G04 P2000；

However, in some hole series processing instructions (such as g82, G88 and g89), in order to ensure the roughness of the hole bottom, when the tool is machined to the hole bottom, there should be a pause time. At this time, it can only be expressed by the address P. if the address x is used, the control system thinks that x is the x-axis coordinate value for execution.

For example, g82x100.0y100.0z-20.0r5.0f200p2000; drilling (100.0100.0) to the bottom of the hole for 2 seconds

G82x100.0y100.0z-20.0r5.0f200x2.0; drilling (2.0100.0) to the bottom of the hole will not be suspended.

2、 The difference and relation of M00, M01, M02 and M30

M00 is the program unconditional pause instruction. When the program is executed, the feed stops and the spindle stops. To restart the program, you must first return to the og state, press CW (spindle forward rotation) to start the spindle, and then return to the auto state and press the start key to start the program.

M01 is the program selective pause instruction. The op stop key on the control panel must be opened before the program is executed. The effect after execution is the same as that of M00. Restart the program as above.

M00 and M01 are often used in the inspection or chip removal of workpiece size in the process of machining.

M02 is the end instruction of main program. Execute this command, feed stop, spindle stop, coolant off. But the program cursor stops at the end of the program.

M30 is the main program end instruction. The function is the same as that of M02, except that the cursor returns to the program head position, regardless of whether there are other program segments after M30.