January 2021 – Page 5 – CNC Machining & Turning, Milling, Metal parts

What is CNC three axis linkage

CNC machining center refers to the spindle axis and vertical machining center setting table, which is mainly suitable for processing plate, plate, shell and small complex parts. Vertical machining center can complete milling, boring, drilling, tapping and thread cutting process. Vertical machining center is at least 3-axis linkage device, generally can realize three-axis linkage. Some five axis and six axis controls can be implemented.

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.

Vertical machining center

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: using compressed air flow pipe, the continuous flow of transmission oil along the pipe, stirring and transportation of oil and gas processing center spindle 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.

Four processing stages of CNC model

When the requirements of surface precision and roughness of parts are relatively high, it is often impossible to complete the processing in one process, and it is divided into several stages for processing.

Four processing stages in the process of making CNC model

(1) Rough machining stage. Rough machining is mainly to cut off most of the machining allowance on each surface to make the shape and size of the blank close to the finished product. This stage is characterized by the use of high-power machine tools, the selection of larger cutting tools, as far as possible to improve productivity and reduce tool wear.

(2) Semi finishing stage. Semi finishing is to finish the machining of secondary surface and prepare for the finishing of primary surface.

(3) Finishing stage. Finish machining is to ensure that the main surface meet the requirements of the drawing.

(4) Finishing stage.

Finishing is a kind of surface with high requirements for surface roughness and machining accuracy, and it also needs finishing. This stage can not be used to improve the position accuracy of parts.

It should be pointed out that the division of processing stages is based on the whole process of parts processing, and cannot be judged by the processing of a certain surface or the nature of a certain process. At the same time, in the specific application, it can not be absolute. For some heavy parts or parts with small allowance and low precision, rough and finish machining can be completed after one clamping.

How to prevent the spindle from colliding with the workpiece

The feed speed of CNC machining center has increased from 16m / min in 1980s to 24-40m / min now. The spindle speed of CNC machining center has also increased from 2500r / min to 6000-40000 R / min now. The structure of CNC machining center has also changed from open type to closed type. Under the condition of such high speed and structure, once the operator has no time to press the emergency stop button due to programming and operation errors, the tool has collided with the workpiece.

In order to prevent machine tool and personal troubles, the following methods can be adopted in programming and operation (take FANUC system as an example).

Under normal conditions, the origin of workpiece coordinate system can be set anywhere, as long as the origin has a certain connection with the origin of machine coordinate system. But in practice, if the command value is zero or close to zero, the tool will point to zero or close to zero. In milling, the cutter will run to the table or fixture base surface; in turning, it will run to the chuck base surface. In this way, the tool will penetrate the workpiece and point directly at the reference plane. At this moment, if you want to move quickly, you will have trouble.

FANUC system generally set: when the decimal point is omitted, it is the minimum input unit, generally μ M. When the decimal point is omitted, the input value will be reduced to one thousandth. At this moment, the input value will be close to zero. Perhaps, due to other factors, the tool should be separated from the workpiece, but the practice is not separated from the workpiece and into the workpiece. In this case, the zero point of the workpiece coordinate system should be set outside the workpiece or on the base surface of the worktable (or fixture), and the result will be different.

Programmers and operators should be more careful about decimal points when writing programs.

FANUC system is the minimum setting unit when the decimal point is omitted, while most domestic systems and some European and American systems are mm when the decimal point is omitted, which is the input method of calculator. If you are used to calculator input method, there will be problems in FANUC system. Many programmers and operators may use both systems. In order to prevent the scale from getting smaller due to decimal point, decimal point should be added to the input program of calculator. To do so is surplus for a certain kind of system, but after the habit is formed, there will be no problems due to the decimal point.

In order to make the decimal point eye-catching, the isolated decimal point is usually written as “. 0” in programming. Of course, when the system is executed, the zero after the decimal point of the value is ignored.

When adjusting the workpiece coordinate system, the operator should set the reference point beyond the physical (geometric) length of all tools, at least on the tool position of the longest tool.

For the workpiece coordinate system on the workpiece installation drawing, the operator obtains it by setting the machine coordinate system offset on the CNC machining center. In other words, the operator sets a reference point on the CNC machining center, finds the scale between the reference point and the zero point of the workpiece coordinate system set by the programmer, and sets this scale as the workpiece coordinate system offset.

On the lathe, the datum point can be set on the base of turret rotation, the datum tool tip or other directions. If there is no additional movement, the zero of the programmer’s instruction is the zero position of the tool rest (CNC machining center) moving to the offset. At this moment, if the datum point is set at the base of turret rotation, the turret must collide with the workpiece. In order to avoid collision, the datum point of CNC machining center should not only be set outside the tool holder, but also outside all tools. In this way, even if the tool is installed on the tool holder, the datum point will not collide with the workpiece.

In CNC machining center, the datum points of X and Y axes are on the axis line of spindle. However, the reference point of the z-axis can be set at the spindle end or at a point other than the spindle end. If it is at the spindle end, when the command is zero, the spindle end will reach the zero position specified in the coordinate system. At this moment, the end key of the spindle end will collide with the workpiece: if the spindle is equipped with a tool again, it will collide with the workpiece. To ensure that there is no collision, the reference point on the z-axis should be set beyond all tool lengths. Even if no other motion is attached, the reference point will not hit the workpiece.

Computer gong processing to prevent accuracy error

It is impossible to make the machining exactly the same as the ideal part, and there will always be different deviations. The deviation degree of the actual geometric parameters after machining from the ideal geometric parameters is called machining error. These machining errors often appear in “large machining process”,

The details are as follows:

Processing economic precision

Because there are many factors affecting the machining accuracy in the machining process, the same machining method can achieve different accuracy under different working conditions. The processing error delta is inversely proportional to the processing cost C. The processing economic precision of a certain processing method should not be understood as a certain value, but as a range, which can be said to be economic.

Original error

There are all kinds of errors in the machining process system composed of machine tool, fixture, cutter and workpiece. These errors will be reflected as the machining errors of workpiece in different ways (or expanding or shrinking) under different working conditions.

The original errors of process system mainly include geometric error, positioning error, processing error caused by force deformation, processing error caused by heat deformation, deformation caused by redistribution of internal stress, principle error, adjustment error, measurement error, etc.

2、 Set error of process system

Geometric error of machine tool

In machining, the forming movement of the tool relative to the workpiece is generally completed by the machine tool. Therefore, the machining accuracy of the workpiece depends on the accuracy of the machine tool to a great extent. The manufacturing errors of machine tools have great influence on the machining accuracy of workpieces: spindle rotation error, guide rail error and transmission chain error. The wear and tear of the machine tool will reduce the working accuracy of the machine tool.

Spindle rotation error

The spindle of machine tool is the datum for clamping the workpiece or cutter, and transmits the motion and power to the workpiece or cutter. The rotation error of spindle will directly affect the accuracy of the workpiece to be processed.

The spindle rotation error refers to the variation of the actual rotation axis of the spindle at each instant relative to its average rotation axis. It can be divided into three basic forms: radial circular runout, axial movement and angular swing.

The main reasons for the radial rotation error of the spindle are: the coaxiality error of several sections of the Journal of the spindle, various errors of the bearing itself, coaxiality error between the bearings, spindle winding, etc. But their influence on the radial rotation accuracy of the spindle varies with different machining methods.

The main reason for the axial movement is the verticality error between the end face of the spindle shoulder and the bearing end face of the spindle rotation axis.

In the process of large-scale machining, the machining error caused by spindle rotation error is different with different machining methods. When machining outer circle and inner hole on lathe, the radial rotation error of spindle can cause roundness and cylindricity error of workpiece, but it has no direct effect on the end face of workpiece. The axial rotation error of CNC machining spindle has little influence on machining outer circle and inner hole, but has great influence on the perpendicularity and flatness of machined end face. When turning the thread, the spindle rotation error can make the lead of the processed thread produce periodic error.

High speed computer gong processing power

Large gantry milling machining center has a strong ability, the workpiece can finish more processing content after clamping at one time, and the processing accuracy is high. For the batch workpiece with medium processing difficulty, its power is 5-10 times of that of general equipment, especially it can finish the processing that many general equipment can’t finish, and it is more suitable for the single piece processing with messy shape and high precision or small and medium batch production with many kinds Use. Here is a brief introduction to the idea of gantry milling machine.

The safe operation of large gantry milling machining center has the following points:

The working object should be clamped by pressing plate, screw or special tool. The general wrench is not allowed to add casing, so as to avoid slipping and injury.

The cutting tool must be clamped firmly, otherwise it is not allowed to drive.

Before work, check the operation of the transmission part of the machine tool, and install the baffle of the machine tool before operation.

When milling various workpieces, especially rough milling, slow cutting should be carried out at the beginning.

When moving the worktable and tool rest, loosen the fixing screw first.

When loading and unloading tools, use copper hammer or wooden mallet to gently hit to prevent tool fragments from flying out and injuring people.

In cutting, it is not allowed to change the speed and adjust the cutting tool. It is not allowed to touch or measure the workpiece by hand.

The gantry milling machine bed is equipped with X-axis guide rail, and the gantry milling machine worktable is fixed on the bed. A gantry is erected on the movable span above the worktable, and the gantry also includes a gantry carriage, which is clamped on the x-axis guide rail. The z-axis guide rail is installed on the gantry. The crossbeam is provided with a Z-axis carriage, the crossbeam is movably clamped on the z-axis guide rail through the z-axis carriage, and the crossbeam is also provided with a Y-axis guide rail.

The milling device of the gantry milling machine is movably installed on the y-axis guide rail, so that the gantry can be milled in the three-dimensional space of X, y and Z axes under the control of the numerical control circuit control system. The CNC gantry milling machine has high precision milling, drilling, boring, cutting and other operations.

a. Reasonable selection of equipment. High machining accuracy is required. Roughing is mainly to cut off most of the machining allowance. Rough machining should be carried out on the machine tool with high power and low precision, while finish machining should be carried out on the machine tool with high precision. Rough machining and finish machining are processed on different machine tools, which can not only give full play to the equipment capacity, but also extend the service life of precision machine tools.

b. In order to ensure the machining accuracy, rough and finish machining should be carried out separately. The amount of cutting is large, because when rough machining. For some parts with high machining accuracy. After roughing and before finishing, low temperature annealing or aging treatment should be arranged to eliminate the internal stress. The cutting force and clamping force of the workpiece are large, the calorific value is large, and there is a significant work hardening phenomenon on the surface of the workpiece. There is a large internal stress in the workpiece. If the rough and rough machining is carried out continuously, the precision of the finished part will be lost quickly because of the redistribution of the stress.

c. Heat treatment process is often arranged in machining process. In order to improve the mechanical properties of parts, quenching and tempering are generally arranged after machining. The location of heat treatment process is as follows: in order to improve the cutting performance of metal, such as annealing, normalizing, quenching and tempering, it is generally arranged before machining. In order to eliminate internal stress, such as aging treatment, quenching and tempering treatment, it is generally arranged after roughing and before finishing. There are many tool materials that can be used in large spark machining, such as diamond, graphite, Cu. Cu based alloy and Cu based composite, and polymer composite is also one of the tool materials for spark machining.

At present, the components of polymer composites used in spark machining are still in the stage of research and development. Good plastic electrodes should have high thermal conductivity, good formability, low resistivity, dimensional stability in water, low coefficient of thermal expansion, and thermal cycling. Compared with graphite electrode, a tool material for spark machining, it has the advantages of low cost, and can be molded into complex geometry. Its manufacturing speed is much faster than milling. The other advantage is that the density is relatively low and the resistivity is relatively high. Therefore, the loss rate of the electrode will be relatively high, but the electrode is in the process of milling In the process of use, it can be trimmed by re molding.

At present, a conductive thermoplastic polymer composite material is used as the electrode, and air and water are used as the working medium to process or polish the surface of the workpiece. Then 60% – 65% of the solid carbon material is evenly distributed in the thermoplastic matrix material to make the electrode. The required geometry can be softened and molded repeatedly.

Influence of tool material on machining quality

Numerical control technology is also called CNC (computerized numerical control). At present, it is the technology of using computer to realize digital program control. In this technology, the computer can control the movement track of the equipment and the operation sequence logic of the peripheral equipment according to the control program stored in advance. Because the numerical control device composed of hardware logic circuit is replaced by computer, all kinds of control functions such as storage, processing, operation and logic judgment of input operation instructions can be realized by computer software, and the micro instructions generated by processing are transmitted to the servo driving device to drive the motor or hydraulic actuator to drive the equipment.

The traditional machining is operated by hand, the ordinary machine tool is used to cut metal by hand, and the accuracy of products is measured by eyes with calipers and other tools. Modern industry has already used computer digital control machine tools for operation, CNC machine tools can automatically process any product and parts directly according to the pre programmed program of technicians. This is what we call NC machining. NC machining is widely used in all fields of machining, and it is the development trend and important and necessary technical means of mold processing. Over the years, users in accordance with the standard, interchange the use of a variety of tool manufacturers produced by the milling cutter and blade. However, these standards make various restrictions on milling cutters and inserts, including the shape and thickness of the inserts, the inscribed circle of the cutting inserts, the size of the holder and wedge clamping parts, and the size of the cutter body. Due to the limited design range of blade material, edge and chip breaking groove, the tool suppliers and users who abide by the standard are limited by the machining function.

However, today, the concept of milling cutter tends to be flexible, which provides tool developers with the freedom to adopt new tools and blade design. These designs can be optimized, and the use of new tool concept can better solve the problems of machining safety, accuracy, appearance quality, metal removal rate, tool overhang, high-speed cutting, and the ability of different cutting paths.

Today’s milling tools are constantly optimized to meet the needs of modern production, machine tools and data, and are widely accepted by all industries. The new tool can remove metal several times faster, with smaller cutting force and better orientation. Its typical runout is only a fraction of the old standard tool. Therefore, the machining tolerance can always be controlled in a smaller range, and the loss of cutting edge is also smaller and more ideal. The axial and radial runout are very small, which means that the accuracy of the cutting edge is improved, so the appearance quality of the workpiece is better, the tolerance is smaller, the tool life is longer, and the cutting load is more uniform, so as to improve the cutting speed and reduce the noise, vibration and loss.

The use of tools also helps to increase spindle speed, high-speed feed and hard part milling, and expands the opportunities for dry cutting. The design of these cutting tools is more concise, and the workload and time required for adjustment and maintenance are very small. The cutter body is rigid and accurate in size. It is made of pre hardened steel, which ensures that the blade is accurately and firmly installed on the milling cutter body, and the appropriate pitch can be selected according to different applications.

The new milling tools use the blade material and groove type developed for specific data or process. The functions and achievements of the new milling tools with these blades are far better than those of ISO or ans standard tools and blades. Compared with most standard inserts, modern new inserts and tools can provide larger rake angle and more complex groove, thus reducing the cutting force and forming the synergistic effect of faster and more stable metal removal.

The transformation brought by CNC machining

NC machining skills have been widely promoted. Most of the machining workshops have NC machining ability. The most common NC machining methods in typical machining workshops are NC milling, NC lathe and NC EDM wire cutting. Because the machining center can complete a variety of processes in a centralized and automatic way, it can avoid man-made operation errors, reduce the time of workpiece clamping, measurement and machine tool adjustment, as well as the time of workpiece turnover, transfer and storage, greatly improve the processing efficiency and accuracy, so it has good economic benefits.

There are many kinds of large CNC machining and CNC lathe machining; from the main categories, there are special CNC lathe machining and general CNC lathe machining; from the processing varieties, there are CNC lathe machining shell, CNC milling machine, processing base, CNC lathe machining shaft, turning center, cam CNC grinder, etc.; from the control request of CNC lathe machining, there are Single axis CNC Abrasive Belt polishing machine includes five linkage CNC gear cutting machine and CNC hob grinding machine; from the complexity of control, there are simple CNC and multi-channel CNC; from the driving method, there are stepper motor, DC servo motor, communication synchronous servo motor, communication asynchronous servo motor and linear motor; from the spindle driving method, there are three parts, There are DC spindle motor, communication spindle motor and communication motorized spindle; in terms of azimuth response method, there are full closed loop response, half closed loop response and open loop control.

The parts processed by CNC lathe should be able to give full play to the technical characteristics of multi process centralized processing of CNC grinder. When CNC grinder processes parts, the condition of grinding wheel cutting workpiece is completely the same as that of corresponding non CNC grinder, but it can carry out some complex processing with machining accuracy requirements. For example, in the grinding range, the general grinder is mainly used for grinding cylindrical and circular CNC lathe The end face of conical surface or stepped shaft shoulder is usually ground by lathe. In addition, CNC cylindrical grinder can also grind torus, as well as the complex combination of the above forms.

High grade and efficient universal active metal cutting machine tool, fine numerical control system with CNC standardization function, computer gong processing can realize the vast majority of drilling, milling, boring, expanding, twisting and other active processing technology, accurately and efficiently finish all kinds of chaotic cam, template, die, arc groove and other typical parts active processing, and can process DNC chaotic parts through RS232 serial port.

As far as the hydraulic buffer for machinery is concerned, it has been oriented to all-round customized planning. For example, it can be used in field and military machinery, crane, high temperature and humid places, etc. Therefore, in planning, it needs to withstand long-term testing before it can become a functional and all-weather commodity. In manufacturing technology, the surface and interior of this type of commodity are highly hardened, heat treated to HRC60 degree and chrome plated, rust resistant and anti-corrosion treatment.

In the high-speed machining base, because the cutting speed is greatly improved, the active tool changing equipment and tool magazine equipment should consider shortening the tool changing time as much as possible, and then cooperate with the high-speed cutting machine tool. The tool changing equipment in the base is generally composed of tool magazine and tool communication organization, and the commonly used methods are manipulator type and non manipulator type. The way and position of tool magazine are also different. In order to meet the needs of high-speed movement, the structure of high-speed machining base is different from that of traditional machining base. It has become the main stream of high-speed machining base planning to reduce the quality of moving parts mainly by tool movement.

Main body description of high speed CNC system

NC machining process is completed in a NC machining process system composed of NC machine tool, cutting tool, fixture and workpiece. CNC plus program controls the movement path of cutting tool relative to workpiece. Therefore, the unity of CNC machine tools, fixtures, tools and workpieces is called CNC machining process system.

numerical control machine. The machine tool that adopts numerical control technology or is equipped with numerical control system is called numerical control machine tool. Numerical control machine tool is a kind of machine integration processing equipment with relatively high technology intensity and automation degree. It is the main body of numerical control processing and the working machinery of parts processing.

High speed CNC fixture. In mechanical manufacturing, the device used to clamp the workpiece and guide the tool is called fixture. In the process of mechanical manufacturing, fixture is widely used, from blank manufacturing to product assembly and testing of each production link, there are many kinds of fixture. The fixture is used to fix the workpiece and keep the correct position, which is the link to realize the data processing.

Tool. Metal cutting tool is an important tool in modern machining, whether it is ordinary machine tool or CNC machine tool, must rely on the tool to complete the cutting work. Tool is the bridge to realize NC machining.

Main elements of high speed CNC programming technology

According to the principle of giving full play to the function of CNC machine tool, the reasonable machining method and process route are determined.
When designing and selecting NC machining tools, the factors such as machining methods, cutting parameters and workpiece materials should be considered to meet the requirements of convenient adjustment, good rigidity, high precision and good durability. When designing and selecting NC machining fixture, it should be able to quickly complete the positioning and clamping process of the workpiece, so as to reduce the auxiliary time. And try to use modular fixture to shorten the production preparation cycle. In addition, the fixture used should be easy to install on the machine tool to coordinate the dimensional relationship between the workpiece and the machine coordinate system.
The selection of high-speed CNC tool setting point is the starting point of program execution. The selection should be based on the principles of simplifying programming, easy alignment, easy inspection in machining process and reducing CNC machining error. The tool setting point can be set on the workpiece to be processed, or on the fixture or machine tool. In order to improve the machining accuracy of parts, the tool setting point should be set on the design basis or process basis of parts as far as possible.
In order to improve the utilization rate of the machine tool, the pre adjustment outside the machine tool should be used as far as possible, and the pre adjustment size should be input into the CNC system in time before running the program, so as to realize the tool compensation.
CNC machining route is determined to ensure the accuracy and surface roughness requirements of the machined parts; shorten the tool path as far as possible, reduce the empty tool travel; it is conducive to simplify the numerical calculation, reduce the number of program segments and programming workload. The process route is formulated to process the parts on the machining center. Due to the many processes of parts processing and the variety of tools used, rough machining, semi finish machining and finish machining have to be completed even under one-time clamping.
The cutting parameters include cutting depth, spindle speed and feed speed. The specific value of cutting parameters should be comprehensively considered according to the provisions of the manual of CNC machine tool, the material of the workpiece to be processed, the processing content and other high-speed CNC process requirements, and combined with the experience data.

The quality of NC process design will directly affect the size accuracy and surface quality of NC machining, the length of processing time, the consumption of materials and labor, and even directly affect the safety of processing. Using large computer gong to process CNC machine parts, the general process from parts drawing to qualified products is as follows:

According to the shape and size of the workpiece, material and technical requirements specified in the part drawing, the large-scale computer gong processing carries out the design and calculation of the process program (including the processing sequence, the relative movement path of the cutter and the workpiece, the stroke and the feed speed, etc.).
Then, according to the form of “numerical control device identification code”, it can be programmed.
The control medium (such as perforated paper tape) is made according to the number code, text code and symbol number on the part processing program sheet.
Through the photoelectric reader, the perforated paper tape converts the optical signal with or without holes into electrical signal and inputs it to the numerical control device.

Processing method of computer gong

Computer gong processing is a complex processing by computer-controlled machine tools. The most complex part of the computer gong is the control system. The computer sends all kinds of instructions to control the three-axis servo motor of the machine. According to the established route, it cooperates with each other to process all kinds of complex processes and ensure high machining accuracy.

What are the common computer gong processing methods

Plane hole parts

Generally, point and line control computer gong machine tools (such as computer gong drilling machine) are used for processing. When selecting the process route, the two principles of processing accuracy and processing efficiency are mainly considered.

Rotating parts

Commonly used computer gong lathe or grinder processing.

a. Consider the processing efficiency: when processing on the lathe, usually the machining allowance is large, we must reasonably arrange the rough machining route to improve the processing efficiency. In actual programming, it is generally not suitable to use cycle instruction (otherwise, there are too many empty tools at work speed). A better way is to cut off the material as soon as possible with rough turning, and then finish turning.

b. Consider the strength of the tool tip: low strength tools are often used in computer gongs and lathes to process small grooves.

Plane contour parts

Commonly used computer gong milling machine processing. It should be noted that:

a. Cut in and cut out direction control: radial cut in, there are pits on the surface of the workpiece; horizontal cut in and cut out, the surface of the workpiece is smooth.

b. First approximation method selection: when machining irregular curve contour, the computer gong machine tool with only linear and circular interpolation function needs to use small linear segment or circular segment to approximate the machined contour (its error is called first approximation error). When approaching, the workpiece error should be within the qualified range, and the number of program segments should be less.

In the production and processing, there are two main forms: solid heat treatment and melt heat treatment. There is a certain difference between the two ways to make precision hardware processing parts. What’s more, they use different steel to make different workpieces.

CNC lathe is composed of bed, headstock, turret feed system, cooling and lubrication system and CNC system. Different from the ordinary lathe, the feed system of CNC lathe is qualitatively different from the ordinary lathe. It does not have the traditional tool box, slide box and change gear frame, but directly uses the servo motor or stepper motor to drive the slide and tool through the ball screw to realize the feed movement. The NC system consists of NC unit, input and output module and operation panel.

(1) Processing methods of precision hardware parts

Solid solution strengthening: because the solute atoms enter into the gap or node of the solvent lattice, the lattice will be distorted and the hardness and strength of the solid solution will be increased. This phenomenon is called solid solution strengthening.
Compound: a new crystal solid structure with metallic properties is formed by the combination of alloy components.

Mechanical mixture: an alloy consisting of two crystal structures. Although it has two kinds of crystals, it is a component with independent mechanical properties.

Ferrite: interstitial solid solution of carbon in a-Fe (body centered cubic iron).
Austenite: interstitial solid solution of carbon in g-fe.
Cementite: stable compound (Fe3C) formed by carbon and iron.
Pearlite: a mechanical mixture of ferrite and cementite (F + Fe3C contains 0.8% carbon)
Ledeburite: a mechanical mixture of cementite and austenite (containing 4.3% carbon) Metal heat treatment is one of the important processes in mechanical manufacturing. Compared with other processes, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but endows or improves the performance of the workpiece by changing the microstructure inside the workpiece or the chemical composition on the surface of the workpiece.

How to electrify CNC machining center

CNC machining center in the process of work, if there is no power on, how to solve the problem

There are two lights on the power supply of CNC machining center unit, one is the power indicator light, which is green, and the other is the power alarm light, which is red. Here, the power supply unit includes the power input unit and the power control part.

First of all, we need to know if the power indicator (green) doesn’t light up when the CNC machining center can’t be connected. The fuse F1 and F2 of the power supply unit have been blown. This is caused by the high input voltage, or the components of the power supply unit itself have been damaged.

The input voltage of CNC machining center is low. Please check the voltage entering the power supply unit. The allowable voltage is ac200v + 10%, 50 Hz ± 1 Hz. The power supply unit is bad, the internal element is damaged, the power indicator light is on, the alarm light also disappears, but the power supply cannot be connected. This is because the power on condition is not satisfied. By the following switch circuit, the conditions of power on are as follows:

There are three conditions for CNC to be connected

First, the source on button is closed.

Second, close the power button.

Third, the external alarm contact is opened.

The alarm light of power supply unit of CNC machining center is on: the fuse of 24 V output voltage is fused, and the + 24 V voltage is used for 1.9 “display screen, as shown in the figure below. Check whether the + 24 V is short circuited to the ground. 2. Poor display / manual data input board.

The above introduction is about how to deal with when the power supply unit of CNC machining center cannot be powered on.