chengcg – Page 42 – CNC Machining & Turning, Milling, Metal parts

CNC computer gong programming and processing

Advantages: 1. High reliability

The reliability of large-scale mechanical parts processing equipment is guaranteed by using highly integrated electronic components, chips and VLSI.

Many functions are realized by software, which reduces the number of hardware.

Rich fault diagnosis and protection functions (mostly realized by software) can reduce the frequency of system failure and the repair time after failure.

Easy to use and maintain

Easy to operate and use: Dongguan computer gong processing users only need to follow the menu prompts, you can operate correctly.

Easy to program: with a variety of programming functions, automatic program verification and simulation functions.

Convenient maintenance and repair: some routine maintenance work is carried out automatically (lubrication, regular inspection of key components, etc.), and the self diagnosis function of CNC machine tool can quickly realize accurate fault location.

Easy to realize mechatronics

Numerical control system control cabinet small size mold processing (using computer, the number of hardware is reduced; the integration of electronic components is higher and higher, and the hardware is constantly reducing), which makes it possible to combine it with machine tool in physics, reduce the floor area and facilitate operation.

Flexibility and versatility

Most of the functions of mechanical parts processing device are realized by software. The modular structure of software and hardware makes the modification and expansion of system functions more flexible.

The basic configuration of mechanical parts processing device is universal. Different CNC machine tools only configure corresponding specific function modules to achieve specific control functions.

Rich CNC functions

Interpolation function: quadratic curve, spline, spatial surface interpolation

Compensation function: motion precision compensation, random error compensation, nonlinear error compensation, etc

Man machine dialogue function: dynamic and static tracking display of processing, advanced man-machine dialogue window

Programming function: G code, basket chart programming, partial automatic programming function.

CNC computer gong processing batch parts

Automatic tool setting system can be used for precision CNC machining. The tool is loaded up one time and one button is used. The machine tool can automatically adjust the tool and process directly. The error is within 0.001 ~ 0.0003 mm, which is not much slower than the automatic change time. If it is a machining center, the efficiency of the machine tool without automatic tool setting device is much higher than that of the machine tool without tool magazine but with automatic tool setting device.

For the domestic manufacturing industry, especially for mold manufacturing enterprises, it is generally single piece production, and labor resources are sufficient. Therefore, for the processing of small batch industrial parts, we should fully consider the use value of funds, and do not use machining center equipment. What’s more, there are still many problems in the tool magazine of domestic manufacturers.

The precision CNC has high machining precision and high machining quality;
CNC machining can carry out multi coordinate linkage, and can process complex shape parts;
When the parts processed by CNC machine tools are changed, only the NC program needs to be changed, which can save the production preparation time;
CNC lathe processing itself has high precision and rigidity. It can choose favorable processing amount and high productivity (generally 3 ~ 5 times of ordinary machine tool);
CNC CNC lathe has high degree of automation, which can reduce labor intensity;
CNC CNC lathe processing batch production, product quality is easy to control;

CNC CNC lathe processing shortcomings:

CNC CNC lathe processing requires lower quality of operators and higher technical requirements of maintenance personnel.
CNC machine tool processing route is not easy to control, not as intuitive as ordinary machine tools.
The lathe is inconvenient to maintain and has high technical requirements;
The processing technology of CNC lathe is not easy to control.

CNC computer gongs machining circular interpolation instructions

When I and K are zero, they can be omitted; regardless of G90 or G91 mode, I, J, K are programmed according to relative coordinates; when circular interpolation, tool compensation instruction G41 / G42 cannot be used.

The advantages and disadvantages between G92 and G54-G59 are the coordinate system set before machining, while G92 is the coordinate system set in the program. If G54-G59 is used, there is no need to use G92 again, otherwise G54-G59 will be replaced and should be avoided, as shown in Table 1. Table 1 difference between G92 and working coordinate system`

Note: (1) once G92 is used to set the coordinate system, G54-G59 will not work unless the system is restarted after power failure or G92 is used to set the required new workpiece coordinate system. (2) After using G92 program, if the machine tool does not return to the original point set by G92, the program will be started again, and the current position of the machine tool will become the new workpiece coordinate origin, which is prone to accidents. Therefore, we hope that readers will use it carefully.

The program of tool changing is compiled.

In the machining center, tool change is inevitable. However, there is a fixed tool change point when the machine tool leaves the factory. If it is not in the position of tool change, it is impossible to change the tool. Moreover, before changing the tool, the tool compensation and circulation must be cancelled, the spindle is stopped and the coolant is turned off. There are many conditions. It is not only easy to make mistakes but also inefficient to ensure these conditions before each manual tool change. Therefore, we can compile a tool change program to save the memory and MDI status

Under the call of M98, the tool change action can be completed at one time.

Taking pmc-10v20 machining center as an example, the program is as follows:

O2002; (program name)

G80g40g49; (cancel fixed cycle, cutter compensation)

M05; (spindle stop)

M09; (coolant off)

G91g30z0; (Z axis returns to the second origin, i.e. tool change point)

M06; (tool change)

M99; (end of subroutine)

When the tool needs to be changed, just type “t5m98p2002” in MDI state to replace the required tool T5, thus avoiding many unnecessary mistakes. According to the characteristics of their own machine tools, the majority of readers can work out the corresponding tool change program.

other

The sequence number of the program segment is represented by address n. Generally, the memory space of NC device itself is limited (64K). In order to save storage space, the sequence number of program segment is omitted.

N only means the segment label, which is convenient to find and edit the program, and has no effect on the processing process. The sequence number can be increased or decreased, and the continuity of the value is not required. However, some loop instructions, jump instructions, calling subroutines and mirror instructions can not be omitted.

In the same program segment, the last occurrence of the same instruction (the same address symbol) or the same set of instructions will work.

For example, tool change procedure, t2m06t3; instead of T2, T3 is replaced;

G01g00x50.0y30.0f200; G00 is executed (although there is f value, G01 is not executed). If the instruction codes are not in the same group, the effect is the same if they are exchanged in the same program segment

CNC high gloss and high precision machining method

Machining surface roughness is one of the important marks to measure the quality of machined surface. It has a great influence on the wear resistance, corrosion resistance, fatigue strength and matching properties of parts. However, there are many factors affecting the surface roughness in machining. In order to achieve good surface roughness, we will learn what these factors are.

1、 The reason of rough machining surface

Residual area: residual area refers to the area that remains on the machined surface after cutting by the main and auxiliary cutting edges of the tool.
Scale: when high-speed steel cutter is used to cut plastic metal materials at low or medium speed, such as low-carbon steel, medium carbon steel, stainless steel, aluminum alloy, etc., fish scale like burr is often produced on the machined surface, which is called scale bone. The appearance of scale will increase the surface roughness of the machined surface significantly.
Chip accretion: in the process of cutting, when the chip accretion is generated, the protruding part can replace the cutting edge to cut into the workpiece, and draw grooves with different depth on the machined surface; when the chip accretion falls off, some of the accumulated debris adhere to the machined surface, forming small burr, resulting in the increase of surface roughness.
Vibration: in cutting process, due to the periodic vibration of the process system, the machined surface appears streaks or ripple marks, and the surface roughness value increases significantly.

Machining: all factors that affect the residual area, scale, scale and vibration affect the surface roughness.

Cutting parameters: feed rate has the greatest influence on the residual area. When the feed rate decreases, the residual area decreases. When cutting plastic metal, when cutting speed is very low or high, the surface roughness value is small. The reason is that it is not easy to produce chip lump at low speed, and the plastic deformation decreases when cutting speed is high, which can eliminate the formation of scale. When cutting brittle materials, the influence of cutting speed is small, because the deformation of material is small, the surface roughness value also decreases.

Geometric parameters of tool: the radius of tool tip arc, main deflection angle and secondary deflection angle have great influence on residual area and vibration. Generally, when the radius of the tool tip arc increases and the main and secondary deflection angles decrease, the surface roughness value is small. However, if the machine tool stiffness is low, the tool tip arc radius is too large or the main deflection angle is too small, the vibration will occur due to the increase of cutting force, which will increase the surface roughness value.

Tool material: the size of the edge arc radius and the time to keep sharp are different with different tool materials. High speed steel tools can be sharpened very sharp, but the time is short, so the surface roughness value is small when cutting at low speed. After grinding, the radius of the edge arc is larger, and the surface roughness is smaller at high speed.

Workpiece material: when processing plastic materials, the lower the plasticity and the higher the hardness of the workpiece material, there will be scaling, scaling and hardening, and the surface roughness will be smaller. Therefore, the surface roughness value of high carbon steel, medium carbon steel and quenched and tempered steel is smaller than that of low carbon steel. When processing cast iron, the chip is of crumbling type, so under the same processing conditions, the surface roughness value of cutting cast iron is larger than that of steel

CNC computer gong machining complex parts

CNC machining center is locked by software. When the automatic operation button is pressed during simulation processing, it is not possible to directly see whether the machine tool has been locked in the simulation interface. In the simulation, there is often no tool setting. If the machine tool is not locked, it is easy to hit the tool. Therefore, before the simulation processing, you should go to the operation interface to confirm whether the machine tool is locked. Forget to turn off the idle switch during processing. In order to save time, the idle switch is often turned on when the program is simulated. Idle running means that all moving axes of the machine tool run at the speed of G00. If the running switch is not turned off during machining, the machine tool will ignore the given feed speed and run at G00 speed, which will cause the accident of cutting and hitting the machine tool. There is no return to the reference point after running the simulation without load. When checking the program, the machine tool is locked, and the tool relative to the workpiece processing is in simulated operation (absolute coordinates and relative coordinates are changing). At this time, the coordinates are inconsistent with the actual position. It is necessary to use the method of returning to the reference point to ensure that the zero point coordinate of the machine is consistent with the absolute and relative coordinates. If there is no problem found after the calibration program, the machining operation will cause tool collision. The direction of override release is wrong.

When the machine tool overtravel, press and hold the overtravel release button and move in the opposite direction with manual or manual mode, which can be eliminated. However, if the direction of release is reversed, it will cause damage to the machine tool. Because when pressing the override release, the over travel protection of the machine tool will not work, and the travel switch of the over travel protection is already at the end of the stroke. At this time, the table may continue to move towards the overtravel direction, and eventually the screw will be broken, causing damage to the machine tool. The cursor position is not correct when the specified line is running. When the specified line is running, it is usually executed from the cursor position down. For the lathe, it is necessary to call the tool offset value of the tool used. If the tool is not called, the tool in the running program section may not be the required tool, which is very likely to cause a tool collision accident due to different tools. Of course, in the machining center, CNC milling machine must first call the coordinate system such as g54 and the length compensation value of the cutter. Because the length compensation value of each knife is different, it may cause knife collision if it is not called.

CNC machining center CNC machine tool as a high-precision machine tool, anti-collision is very necessary, require the operator to develop a careful habit, according to the correct method to operate the machine tool, reduce the occurrence of tool collision. With the development of technology, there are some advanced technologies, such as tool damage detection, anti-collision detection and adaptive machining, which can better protect CNC machine tools. After the industrial revolution, the pace of production can be said to be faster and faster. Nowadays, CNC machine tools seem to be used in many fields, because of the precise control and high-end technology, the product specifications produced by them are also more standardized. All of this, thanks to CNC complex parts processing technology is becoming more and more high-end, because of this, so modern we can enjoy the production mode and efficiency that we did not dare to think of before.

Since the advent of CNC machine tools, more and more manufacturers have begun to introduce such good machinery into their respective industries. Businesses hope to pursue high output, but also require products to meet production standards. This is a very strict requirement for the machine tool. It not only requires the working efficiency of the whole machine tool to maintain high efficiency, but also has many fine requirements for each internal part. CNC complex parts processing can be said to be the basis for ensuring the overall quality of CNC machine tools. Only by ensuring that the processing technology of CNC complex parts remains at a high level, can many manufacturers be assured of using it Create more and better products.

Therefore, for businesses, the first thing to do is to be ingenious in the selection of CNC complex parts processing, can not rely on the price alone, also can not be blindly selected. For manufacturers, the best way is to select the best quality CNC through a variety of ways, which can not only increase more safety scores for future production

CNC computer gong processing fault analysis

Fault analysis: after measuring the workpiece, it is found that the relative positions of all dimensions of the parts are correct, but all the coordinate values of X axis are different by 10 mm. By analyzing the causes, the whole pitch deviation of x-axis dimension (the pitch of this axis is 10 mm) is caused by the offset of reference point position.

For most systems, the reference point is generally set on the “zero pulse” of the first programmer after the release of the deceleration iron at the reference point; if the reference point deceleration block is released, the encoder happens to be near the zero pulse, and due to the random error of the deceleration switch action, the reference point position may be shifted by one whole pitch. This fault is especially easy to happen when using small pitch ball screw.

Troubleshooting: for this kind of fault, as long as the position of the deceleration stop at the reference point is readjusted so that the difference between the release point of the stop and the “zero pulse” position is about half a pitch, the machine can resume normal operation. After the above treatment, the fault is removed and the machine returns to normal operation. After the above treatment, the trouble is eliminated, the machine tool returns to normal, and all parts are processed normally.

1、 Machine parts processing plant – types of mechanical parts:

The first type is mainly used in precision machinery, which has high requirements for the stability of the fit. It requires that the wear limit of the parts should not exceed 10% of the dimensional tolerance value of the parts in the process of use or after many times of assembly. This is mainly applied to the surfaces of precision instruments, meters, precision measuring tools, and friction surfaces of extremely important parts, such as the inner surface of cylinder, the main journal of precision machine tools, and the coordinate boring machine Main journal, etc.

The second type is mainly used in ordinary precision machinery, which requires high stability of fit. The wear limit of parts shall not exceed 25% of the dimensional tolerance value of the parts. It is mainly used in machine tools, tools, surfaces matching with rolling bearings, taper pin holes, and contact surfaces with higher relative speed, such as the mating surfaces of sliding bearings and gears Gear tooth working face, etc.

The third category is mainly used in general machinery, which requires that the wear limit of mechanical parts shall not exceed 50% of the dimensional tolerance value. The contact surfaces of parts without relative movement, such as box cover and sleeve, shall be close to each other, the working surface of key and keyway, and the contact surface with low relative movement speed, such as support hole, bushing, working surface with wheel axle hole, reducer, etc.

2、 Mechanical parts processing plant — manufacturability of mechanical parts:

When designing mechanical parts, we should not only make them meet the requirements of use, that is, they should have the required working capacity, but also meet the production requirements. Otherwise, they may not be manufactured, or they can be manufactured, but they are costly and uneconomical. Under specific production conditions, if the designed mechanical parts are easy to process and the processing cost is very low, then such parts are said to have good processability. The basic requirements for processability are as follows:

(1) The method of blank preparation in mechanical manufacturing includes: direct use of profile, casting, forging, stamping and welding. The selection of blank is related to the specific production technical conditions, and generally depends on the production batch, material properties and processing possibility.

(2) When designing the structural shape of parts with simple structure, the simplest surface (such as plane, cylindrical surface and spiral surface) and their combination should be adopted. At the same time, the number of machined surfaces and the area of machining should be minimized.

(3) With the increase of precision, the machining cost of parts increases with the increase of precision, especially in the case of high precision. Therefore, high precision should not be pursued without sufficient basis. In the same way, the surface roughness of parts should also be regulated according to the actual needs of the mating surface.

CNC computer gong machining thin wall parts

In a broad sense, it refers to the process that all products can be manufactured by mechanical means; in a narrow sense, it refers to the process of making parts by special machinery such as the lathe, milling machine, drilling machine, grinding machine, stamping machine, die-casting machine, etc.

There will be some errors in machining. Let’s talk about the original error related to the initial state of the process system itself

① Principle error is the error of machining method.

② Geometric error of process system

The relative position errors between workpiece and tool exist in static state, such as manufacturing error of tool and fixture, adjustment error and installation error;

The relative position error of workpiece and cutter exists in the motion state, such as the spindle rotation error of machine tool, the guide error of guide rail, the transmission error of transmission chain, etc.

The deformation caused by the force effect of the process system, such as the deformation caused by the stress deformation of the process system and the deformation caused by the generation and disappearance of the internal stress of the workpiece.

② Deformation caused by thermal effect of process system, such as the error caused by thermal deformation of machine tool, cutting tool and workpiece. In the machining process of mechanical parts, when the position relationship between the tool and the workpiece processing surface is reasonable, the machining surface accuracy can meet the processing requirements, otherwise it can not meet the processing requirements. CNC machining accuracy analysis is to analyze and study various factors when the machining accuracy can not meet the requirements, that is, the possibility of various original errors, and take effective technological measures In order to improve the machining accuracy.

What is CNC five axis machining

What is CNC five axis machining center? What are the characteristics of five axis machining center

Definition of five axis: there are at least five coordinates on a machine tool, which are three linear coordinates and two rotation coordinates

Five axis machining features:

a. 3-axis machine tools can not process or need to clamp too long; B. improve the accuracy, quality and efficiency of free space surface

The difference between five axis and three axis; the difference between five axis and three axis; the establishment of five axis coordinate and the expression of its code

Determination of z-axis: the axis direction of machine tool spindle or the vertical direction of worktable for clamping workpiece is z-axis

Or the direction of the axis parallel to the axis of the workpiece in the horizontal plane

Linear coordinate X axis Y axis Z axis rotation coordinate a axis, b axis and C axis

Axis A: axis A is rotated around X axis

B axis: rotate around Y axis to b axis

C axis: rotate around Z axis for C axis

XYZ + A + B, XYZ + A + C and XYZ + B + C five axes

Five axis can be divided into two categories: horizontal and vertical

The five axis linkage is determined by the relationship between the rotating spindle and the linear motion

Double rotary table (a + B as an example)

Add a rotating table of a-axis on the b-axis rotary table, small turbine, impeller and compact die

High rigidity precision of a + B B + C
The double swing head worktable is large and powerful, suitable for processing large workpieces, gantry type

Rotation range of five axis linkage structure:

Rotation range of double rotary table + 20a-100 b360 + 30a-120 C360

Rotation range: 30b-120 C360

Rotation range of double pendulum head is + 90a-90 C360 + 30

ISO knowledge of CNC machining

ISO9000 has several main characteristics, which can be summarized as “one essence and one center, two basic points; three characteristics, four general affairs and four major products, five major modules, six documents and eight principles”. I will simplify it to “112 344 568”

① One essence: speaking, writing and doing are consistent;

② One center: customer centered

③ Two basic points: customer satisfaction and continuous improvement

④ Three characteristics: suitability, sufficiency and effectiveness.

⑤ Four things: everyone is responsible for everything, there are rules to follow for everything, there is evidence for everything, and there is someone to supervise everything.

⑥ Four products: service, software, hardware and process materials.

⑦ Five modules: (1 total process, 4 major processes)

Quality management system; management responsibility; resource management; product realization; measurement, analysis and improvement

⑧ Six documents: the six procedure documents clearly put forward by ISO9000:2000 standard must be formulated

Document control procedures, quality record management procedures, internal audit procedures

Control procedures of unqualified products, corrective measures and preventive measures.

⑨ Eight principles: customer centered, leadership role, CNC computer gong processing in Dongguan

Staff participation, process method, system management, continuous improvement, fact based, mutually beneficial relationship with suppliers.

Seven techniques of IE

① Program analysis;

② Time analysis;

③ Movement analysis

④ Pipeline analysis;

⑤ Dynamic analysis of crops;

⑥ Material analysis;

⑦ Environmental analysis

Types of common surface treatments:

① Grinding (polishing)

② Electroplating

③ Spraying / baking

④ Heat treatment

⑤ PVD (vacuum coating)

⑥ Sandblasting

⑦ Vehicle pattern

⑧ Scratch (wire drawing)

⑨ Oxidation (coloring)

⑩ Matte

Making black

(12) trimming

The flower of the flower`

Ten steps to RoHS compliance

The first step is to determine the correlation between enterprise products and ROHS directive. (if it is determined that the products produced by the enterprise are within the jurisdiction of RoHS, then go to the second step

Step 2: set up a company wide “compliance” team within the enterprise.

Step 3: establish RoHS compliance statement.

Step 4: establish the implementation plan of RoHS compliance within the enterprise.

CNC computer gongs processing design basis

Design datum: the datum used to determine the position of other points, lines and planes on the part drawing, which is called design datum.

Process datum: the datum used in the process of machining and assembling parts, which is called process datum. According to different uses, process datum can be divided into assembly datum, measuring datum and locating datum.

(1) Assembly datum: the datum used to determine the position of parts in parts or products during assembly, which is called assembly datum.

(2) Measurement datum: the datum used to check the size and position of machined surface, which is called measuring datum.

(3) Positioning datum: the datum used for workpiece positioning during machining, which is called positioning datum. For the surface (or line, point) as positioning reference, only the rough surface can be selected in the first working procedure. This positioning surface is called rough datum. The machined surface can be used as the positioning datum in the following processes, and the positioning surface is called the precise datum.

In the process of turning a blank into a finished product, the total thickness of the metal layer cut off on a machining surface is called the total machining allowance of the surface. The thickness of the metal layer cut by each process is called the machining allowance between processes. For the rotating surface such as outer circle and hole, the machining allowance is considered from the diameter, so it is called symmetrical allowance (i.e. bilateral allowance), that is, the actual thickness of the metal layer cut off is half of the machining allowance on the diameter. The machining allowance of the plane is the unilateral allowance, which is equal to the actual thickness of the metal layer removed. The purpose of leaving machining allowance on the workpiece is to remove the machining errors and surface defects left by the previous process, such as the surface cold and hard layer, air hole and sand inclusion layer on the casting surface, oxide scale, decarburization layer and surface crack on the forging surface, internal stress layer and surface roughness after cutting. The precision and surface roughness of the workpiece are improved. The size of machining allowance has great influence on machining quality and production efficiency. If the machining allowance is too large, it not only increases the labor of machining, reduces the productivity, but also increases the consumption of materials, tools and power, and increases the processing cost. If the machining allowance is too small, it can not eliminate all kinds of defects and errors in the previous process, and can not compensate for the clamping error in this process, resulting in waste products. The selection principle is to make the allowance as small as possible on the premise of ensuring the quality. Generally speaking, the more finish machining, the smaller the process allowance.

Applicability: