肯堂 – Page 5 – CNC Machining & Turning, Milling, Metal parts

Computer gong processing method

Using precision level instrument and other testing tools, the main bed level of the computer gong processing machine tool is precisely adjusted by adjusting the pad iron, so that the geometric accuracy of the machine tool can reach the allowable tolerance range;
For the automatic tool changing device, adjust the position of tool magazine, manipulator, stroke parameters, etc., and then check the action with instructions to ensure accuracy;
For the machine tool with APC automatic exchange table, after adjusting the relative position, carry out automatic exchange;
After adjusting 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, and the execution of common instructions.

Check the normal operation of the machine tool and accessories. CNC computer gong NC machining is the basis of modern manufacturing technology, the invention of electricity for the manufacturing industry, has epoch-making significance and far-reaching influence. When clamping the workpiece, according to the way of clamping and placing in the programming operation instruction, it should be considered to avoid the processing parts and the situation that the cutter head may encounter the fixture in the processing.

After the workpiece is placed on the pad iron, it is necessary to pull the table for the workpiece datum according to the drawing requirements. For the workpiece that has been ground on six sides, it is necessary to check whether its verticality is qualified.

The nut must be tightened after the work-piece is pulled to prevent the work-piece from shifting during the processing due to the loose clamping; pull the work-piece again to ensure that the error does not exceed the tolerance after the clamping.

3、 Number of workpieces touched

For the clamped workpiece, the contact head can be used to set the processing reference zero position. The contact head can be used in photoelectric type and mechanical type. There are two kinds of methods: middle collision number and unilateral collision number

Photoelectric static, mechanical speed 450 ~ 600rpm. Manually move the x-axis of the worktable according to the collision number to make the collision number head touch one side of the workpiece. When the collision number head just touches the workpiece and the red light is on, set the relative coordinate value of this point to zero. Then manually move the x-axis of the worktable to make the collision number head touch the other side of the workpiece. When the collision number head just touches the workpiece, record the relative coordinate at this time.

According to the relative value minus the diameter of the collision head (i.e. the length of the workpiece), check whether the length of the workpiece meets the requirements of the drawing.

Computer gong processing vertical processing

The height of the vertical machining center is limited, which reduces the processing range of the workpiece, which is the disadvantage of the vertical machining center. However, the workpiece clamping and positioning is convenient for vertical machining center; the cutting path is easy to observe and debug, the program inspection and measurement is convenient, the problems can be found in time, and the treatment or modification can be stopped; the cooling conditions are easy to establish, and the cutting fluid can directly reach the surface of the cutting tool and processing; the three-axis and Cartesian coordinate system, intuitive feeling, in line with the design point of view, the chip is easy to exclude and modify, Surface treatment to avoid scratches. Compared with the corresponding horizontal machining center, it has the advantages of simple structure, small floor area and low price.

Mainly used for:

Using grease and oil circulation in machining center will produce abnormal heating.
Spindle, need high-definition washing, high-speed bearing sealing place

working principle:

The use of compressed air flow pipe, transmission oil along the pipe caused by continuous flow, stirring and transportation of oil and gas processing center spindle part and other parts of the screw need lubrication. The constant pressure dry compressed air (bar) 5 – 8 continuous supply, according to the spindle and lubricating oil lubrication, screw oil and other parts of the fuel consumption different quantitative supply. Therefore, each lubrication circuit must use a separate micro pump power supply of oil. After the oil pump, it must enter the oil and natural gas mixing valve. In the oil and natural gas mixing valve, the compressed air flow blows into small oil drops and adheres to the wall to form an oil film. The flow direction of the air flow between the oil film and the pipe wall, and the thickness of the medium oil film gradually becomes thinner, but not together.

Maximum depth allowed for each cutting, actual m auxiliary function, s speed, t tool change, R radius, u, W are relative G: preparation command M: auxiliary command T: tool s: spindle speed, R: arc radius, and then p q R, where R means different.

Structure of computer gong machine

Casting, which is the most important part of the computer gong, directly affects the accuracy, stability, wear resistance of the computer gong and the service life of the machine tool. After the casting is finished, Dongguan computer gong processing is not immediately used in production. The good casting is that after wind and rain, sun exposure, natural weathering, some of them are soaked in sea water, and then processed until the casting does not change. The machine tool made in this way is not easy to change, and can maintain the stability and accuracy of the machine tool for a long time.
Spindle, the spindle is used to directly face the workpiece, it is driven by the motor to work, high-speed rotation, the spindle is equipped with a tool handle, it can chip the workpiece, meet various production needs, the quality of the spindle will directly affect the processing accuracy, if the internal bearing is worn, it is easy to cause the swing of the spindle, the accuracy of the processed things naturally has a few deviations . At present, the rotation speed of the main shaft is generally about 8000 rpm, and the high-speed machine can achieve more than 20000 rpm, and each machine has only one main shaft.
The screw rod is also a part of the fuselage. The machining of mechanical parts is driven by the servo motor. The displacement of the worktable is driven by the copper sleeve of the screw rod to meet the machining needs. If there is a gap in the screw rod, it is also directly reflected in the machining accuracy and finish.
There are two kinds of motors: servo motor and frequency conversion motor. The servo motor has good stability, high power of spindle drive motor and low coordination rate of three-axis drive motor.
The coupling is installed between the screw rod and the motor, which is just a linkage function.
The lubrication cooling system consists of an automatic oil pump, a spindle oil cooler and a chip liquid circulation system. The machine oil can be automatically fed and automatically pumped without manual operation

Elements of cutting conditions

For high efficiency metal cutting, the processed materials, cutting tools and cutting conditions are the three major elements. It determines the processing time, tool life and processing quality. The economic and effective machining method must be reasonable selection of cutting conditions.

The three elements of cutting conditions: cutting speed, feed and cutting depth directly cause tool damage. With the increase of cutting speed, the temperature of tool tip will rise, which will produce mechanical, chemical and thermal wear. If the cutting speed is increased by 20%, the tool life will be reduced by 1 / 2.

The relationship between the feed condition and the tool wear is very small. But when the feed rate is large, the cutting temperature rises, and the back wear is large. It has less influence on the tool than the cutting speed. Although the influence of cutting depth on the tool is not as big as cutting speed and feed rate, the hardened layer of the material to be cut will also affect the life of the tool.

Reasonable selection of cutting tools

① In rough turning, the cutting tools with high strength and good durability should be selected, so as to meet the requirements of large back feed and large feed.

② When finishing turning, the cutting tools with high precision and good durability should be selected to meet the requirements of machining accuracy.

③ In order to reduce the tool changing time and facilitate tool setting, the machine clamping tool and machine clamping blade should be used as far as possible.

Reasonable selection of fixture

① Try to use general fixture to clamp workpiece, avoid using special fixture;

② In order to reduce the positioning error, the positioning datum of parts coincides.

Determine the processing route, which refers to the movement path and direction of the cutter relative to the part in the process of NC machine tool processing.

① It should be able to meet the requirements of machining accuracy and surface roughness;

② The processing route should be shortened as far as possible to reduce the tool idle travel time.

Skills of tool changing in computer gong processing

When programming the computer gong, we should first consider the selection of tool setting point, and the determination of tool setting point and tool changing point. Tool setting point is the starting point of tool movement relative to the workpiece in NC machining. Since the program is also executed from this point, the tool setting point is also called the program starting point or tool starting point.

When the machining accuracy is not high, some surfaces on the workpiece or fixture can be directly used as the tool face; when the machining accuracy is high, the tool setting point should be selected on the design basis or process basis of the part as far as possible, for example, for the part with hole positioning, it is more appropriate to take the axis of the hole as the tool setting point. The tool setting point must have a certain coordinate relationship with the positioning datum of the workpiece. In this way, the relationship between the machine tool coordinate system and the workpiece coordinate system can be determined. The choice of tool setting point for computer gong processing should be convenient for coordinate value calculation and tool setting. During tool setting, the tool setting point should coincide with the tool position. The so-called tool position refers to the intersection of the tool axis and the tool bottom surface for flat end milling cutter; the ball end milling cutter refers to the ball center of the ball head part; the turning tool refers to the tool tip; the drill bit refers to the drill tip; the machining of mechanical parts refers to the focus of the wire electrode axis center and the part surface for wire electrode cutting machine.

Introduction of CNC machining center

Machining center is often divided into vertical machining center and horizontal machining center according to the state of the spindle in the space. The vertical machining center whose spindle is vertical in the space is called vertical machining center, and the horizontal machining center whose spindle is horizontal in the space is called horizontal machining center. Spindle can be vertical and horizontal conversion, known as vertical and horizontal machining center or five machining center, also known as composite machining center. According to the number of machining center columns, there are single column type and double column type (gantry type).

The technology of high-speed CNC machining is the premise to ensure the production of high-quality parts.

On lathe, the shape and size of the blank can be changed by the rotary motion of the workpiece and the linear or curvilinear motion of the cutter, and it can be processed to meet the requirements of the drawing.

Ordinary machine tools are more and more difficult to meet the needs of processing precision parts. At the same time, due to the improvement of production level, the price of CNC machine tools is falling from time to time. CNC precision parts processing mainly includes ultra precision turning, mirror grinding and grinding.

The primary premise of CNC precision parts processing is the accuracy of process datum. Datum on mechanical drawings are represented by capital letters a, B, C, D, etc. with a specific reference symbol with circle. When the reference symbol is aligned with the surface and its extension line or the dimension limit of the surface, the surface is taken as the datum. When the datum mark is aligned with the dimension line, it means that the solid center line of the dimension is taken as the datum. It is a more general statement that the process is accurate.

Assembly benchmark refers to the precision used to determine the position of parts in components or products during assembly. Measurement datum refers to the specification for the size and position of the machined surface to be measured during the inspection of parts. Positioning datum refers to the datum used for positioning the workpiece in the machine tool or fixture during machining.

CNC machining center

The biggest difference between CNC milling machine and machining center is that the machining center has the ability to exchange machining tools automatically. By installing different tools on the tool magazine, the machining tools on the spindle can be changed through the automatic tool changing device in one clamping, and a variety of machining functions can be realized.

CNC machining center is composed of mechanical equipment and CNC system, which is suitable for processing complex parts. CNC machining center is one of the most widely used CNC machine tools with the highest output in the world. Its comprehensive processing ability is strong, the workpiece can complete more processing content after clamping at one time, and the processing accuracy is high. For the batch workpiece with medium processing difficulty, its efficiency is 5-10 times higher than that of ordinary equipment, especially it can complete the processing that many ordinary equipment can’t complete, and it is more suitable for single piece processing with complex shape and high precision requirements or small and medium batch multi variety production. It concentrates the functions of milling, boring, drilling, tapping and cutting threads on one equipment, so that it has a variety of technological means. Machining centers are classified into horizontal and vertical machining centers according to the spatial position of the spindle. According to the classification of process uses: boring and milling machining center, composite machining center. According to the special functions, there are single table, double table and multi table machining centers. Machining center of single axle, double axle, three axle and changeable headstock.

Introduction of mould making process

Smelting quality for high-quality die steel, the processes of out of furnace refining, vacuum treatment, vacuum smelting, powder injection treatment and electroslag remelting are widely used at home and abroad to reduce the contents of harmful elements, oxygen, hydrogen and inclusions in the steel and fine tune the chemical composition and pouring temperature. By ESR, the macrostructure and density of the steel can be effectively improved, and the isotropy of the die steel can be improved. The tests in some domestic factories show that the transverse impact toughness of 4Cr5MoSiV1 steel produced by electric arc furnace is only 31% of the longitudinal impact toughness. After ESR, the transverse impact toughness of 4Cr5MoSiV1 steel is 70% of the longitudinal impact toughness, which is more than doubled. For the die steel with special requirements, the P / m high speed steel and P / m high alloy die steel can better improve the microstructure and properties of the steel.
On the basis of a certain forging ratio, upsetting drawing forging and cross rolling should be adopted as far as possible to improve the isotropy of die material. In order to reduce machining allowance and improve material utilization, precision forging machine, fast forging hydraulic press and high-precision continuous rolling mill are widely used to provide high-precision steel to meet the needs of mold manufacturing.
For heat treatment and finishing of forged and rolled products, controlled atmosphere or vacuum heat treatment should be adopted to avoid oxidation and decarburization. Some plastic die steel and hot work die steel should be pre hardened by Metallurgical Department. For some hot working die materials with high requirements, the Metallurgical Department should refine the structure in advance to eliminate the coarse carbides and chain carbides in the steel, and obtain fine and uniform carbides, so as to further improve the various properties of the steel, especially the isotropy. According to some foreign reports, some hot work die steels are produced with high quality and high directivity by electroslag remelting, multi-directional forging (rolling) and microstructural refinement. The transverse impact toughness can be equal to more than 90% of the longitudinal impact toughness. In addition, considering the metallurgical quality of various parts of steel, attention should be paid to make the main working face of the mold (such as cavity or edge) close to the surface of steel; because in general, the surface of steel is the clean part of steel, while the center of steel is the area where the macrodefects are concentrated; especially in the large section ledeburite steel, the center part is the center part The inhomogeneity of eutectic carbide in steel is 2-3 grades higher than that on the surface. In addition, the main load bearing direction of the die should be consistent with the deformation direction of the steel, so as to reduce the adverse effect of the anisotropy of the steel on the die.
Thermal conductivity thermal conductivity is also one of the main performance indicators of die steel, especially some hot work die steel and plastic die steel. Mold steel with good thermal conductivity can quickly transfer the heat generated in the processing and the heat from the workpiece, avoid overheating on the working surface of the mold, and improve the working conditions of the mold. For some thermoplastics forming dies and some die-casting dies, in order to speed up the pace of production, it is hoped that the pressed workpieces can be cooled and demoulded quickly to improve productivity. In order to solve this problem, sometimes some die materials with better thermal conductivity than steel are selected, such as high-strength copper alloy, high-strength aluminum alloy, etc.

What is machining center three axis, four axis

The spindle in the horizontal state of space is called horizontal machining center. Spindle can be vertical and horizontal conversion, known as vertical and horizontal machining center or five machining center, also known as composite machining center. According to the number of machining center columns, there are single column type and double column type (gantry type).

According to the coordinate number of machining center movement and the coordinate number of simultaneous control, there are three axis two linkage, three axis three linkage, four axis three linkage, five axis four linkage, six axis five linkage, etc. Three axis and four axis refers to the number of motion coordinates of the machining center. Linkage refers to the number of coordinates that the control system can control at the same time, so as to realize the position and speed control of the tool relative to the workpiece. Machining center can be divided into vertical, horizontal and composite machining center from the appearance. The spindle of the vertical machining center is perpendicular to the worktable, which is mainly used for processing plate and shell workpieces, and can also be used for mold processing.

The spindle axis of the horizontal machining center is parallel to the worktable, and its worktable is mostly a CNC rotary table controlled by servo motor. In the one-time clamping of workpieces, multiple machining surfaces can be processed through the rotation of the worktable, which is suitable for the processing of box workpieces. The compound machining center mainly refers to that there are two vertical and horizontal spindles on one machining center, or the spindle can change the angle by 90 degrees, so it can realize the machining of five surfaces in one clamping of workpiece.

What is vertical machining center

The spindle of the vertical machining center is perpendicular to the worktable, which is mainly used for processing plate and shell workpieces, and can also be used for mold processing. The spindle axis of the horizontal machining center is parallel to the worktable, and its worktable is mostly a CNC rotary table controlled by servo motor. In the one-time clamping of workpieces, multiple machining surfaces can be processed through the rotation of the worktable, which is suitable for the processing of box workpieces. The compound machining center mainly refers to that there are two vertical and horizontal spindles on one machining center, or the spindle can change the angle by 90 degrees, so it can realize the machining of five surfaces in one clamping of workpiece.

Machining center is usually divided into vertical machining center and horizontal machining center according to the state of spindle in space

The vertical machining center whose spindle is vertical in space is called vertical machining center, and the horizontal machining center whose spindle is horizontal in space is called horizontal machining center. Spindle can be vertical and horizontal conversion, known as vertical and horizontal machining center or five machining center, also known as composite machining center. According to the number of machining center columns, there are single column type and double column type (gantry type).