CNC Technology Archives - CNC Machining & Turning, Milling, Metal parts

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The function of CNC computer gong processing

Computer gong processing is now widely used in daily life

The parts with complex structure and shape, which are difficult to be processed by ordinary machine tools, need multi coordinate linkage processing when the main surface is composed of complex curves and curved surfaces, which is difficult or even impossible to be completed on ordinary machine tools. Numerical control processing equipment is the most effective equipment for processing such parts. The common typical parts of computer gong processing are cam, integral impeller and mold.

① There are various kinds of curved disc cam, cylindrical cam, conical cam and end face cam. When machining, according to the complexity of the cam surface, three axis, four axis or five axis machining center can be selected.

② Integral impellers are commonly used in aero-engine compressors, air compressors, marine underwater propellers, etc,

In addition to the characteristics of general curved surface machining, there are many special machining difficulties in mold machining, such as narrow channel, easy tool contact with machined surface and adjacent curved surface.

The CNC center of parts with both plane and hole system has automatic tool changing device. In one installation, it can complete the milling of the upper plane of parts and the multi-step machining of hole system, such as drilling, boring, reaming, milling and tapping. The processing part can be on one plane or on different planes. The pentahedron machining center can complete the machining of five surfaces except the clamping surface. Therefore, the parts with both plane and hole system are the preferred processing objects of computer gongs. The common parts include box parts and plate, sleeve and plate parts.

① There are plane, curved surface and hole system on the end face of parts, and some radial holes are often distributed in the radial direction. The vertical processing equipment should be selected for the disc, sleeve and plate parts whose processing parts are concentrated on a single end face, and the horizontal processing equipment should be selected for the parts whose processing parts are not located on the surface in the same direction.

② Box parts are common box parts. Box parts generally need multi station hole system and plane processing, with high accuracy requirements, especially the shape accuracy and position accuracy. They usually need to go through milling, drilling, expanding, boring, reaming, countersinking, tapping and other steps, and need more tools. It is difficult to process on ordinary machine tools, and the number of tooling sets is large. It needs multiple clamping and alignment, and manual measurement times are many, so the accuracy is not easy Guarantee. The last installation of CNC machining center can complete 60% ～ 95% of the process content of ordinary machine tool, with good consistency of parts precision, stable quality and short production cycle.

Now, the middle and low-grade CNC has such a large function that it may also be accepted by users to process molds. It is generally considered that CNC is the limiting factor to determine the maximum feed rate of die processing, but now, the limiting factor is often the structure of the machine tool itself. If the machine itself is already running at its performance limit, a better CNC will not transmit more functions

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CNC five axis computer gong processing technology

It is a difficult point for five axis parts to process multi-dimensional surface parts. In addition to the application of multi axis machine tool, multi axis programming technology is the key. Reasonable setting of machining tool path is an important guarantee for the surface accuracy and dimensional accuracy of parts. Five axis parts processing taking human head image processing as an example, this paper discusses and analyzes the practical application of five axis cutting to multi-dimensional surface parts processing.

Five axis parts processing has the characteristics of high efficiency and high precision, the workpiece can complete complex processing with one clamping. It can adapt to the processing of modern molds such as auto parts and aircraft structural parts. There is a big difference between five axis machining center and pentahedron machining center. Many people don’t know the five axis machining, and mistakenly regard the pentahedron machining center as the five axis machining center. Five axis machining center has x, y, Z, a, C five axis, XYZ and AC axis form five axis linkage processing, good at space surface processing, special processing, hollow processing, drilling, oblique hole, oblique cutting and so on. Five axis parts processing and “pentahedron machining center” is similar to the three-axis machining center, but it can do five faces at the same time, but it can’t do special-shaped processing, oblique hole, cutting slope, etc.

A five axis machining type for mechanical parts relates to a five axis manipulator. Its main features are that the shoulder mechanism and the reducer shaft of the waist mechanism fixed on the fixed seat are fixedly installed to realize the radial swing of the shoulder mechanism and the reducer shaft of the fixed seat, the elbow mechanism and wrist mechanism for five axis mechanical parts processing realize the relative swing between the shoulder mechanism and the elbow mechanism, and the elbow mechanism and wrist mechanism respectively, and the five axis mechanical parts processing claw mechanism is installed on the bevel gear shaft of the wrist mechanism and passes through A pair of gears installed on the wrist mechanism reducer are meshed with the bevel gears of the claw mechanism.

Five axis machine parts processing type has simple structure, comprehensive functions, good reliability, stability and accuracy of the whole machine. It can perfectly replace the existing manipulator, and is suitable for welding, assembly, processing and other industrial systems. Five axis mechanical parts processing CS Series manipulator is suitable for 500 ~ 3000 tons of various types of horizontal injection molding machine products and nozzle extraction. The upper and lower arm type is variable section type; the up and down stroke is 800 ~ 3000mm, and the X, y, Z three axes are driven by AC servo motor. The installation can increase the production capacity (20 ~ 30%), reduce the defective rate of products, ensure the safety of operators, reduce labor, accurately control the production volume, and reduce waste.

The five axis mechanical parts processing is driven by drive components such as motor, reducer, pulley mechanism, sprocket mechanism, etc. it is characterized in that: the manipulator includes waist mechanism, shoulder mechanism, elbow mechanism, wrist mechanism and claw mechanism. The five axis mechanical parts processing shoulder mechanism and the reducer shaft of waist mechanism fixed on the fixed seat are fixed together The elbow mechanism and wrist mechanism are respectively installed in the shoulder mechanism and the reducer in the elbow mechanism to realize the relative swing between the shoulder mechanism and the elbow mechanism, and between the elbow mechanism and the wrist mechanism. The five axis mechanical parts processing claw mechanism is installed on the bevel gear shaft of the wrist mechanism, and is installed on the reducer of the wrist mechanism The engagement of a pair of bevel gears with the claw mechanism realizes the swing or rotation of the claw mechanism.

Five axis impeller machining supports four axis roughening, and some manual settings can be made in the control of the axis. Of course, in the process of generating the program, automatic avoidance can adjust these parameters. Channel finishing method is mainly used to finish the channel surface of five axis impeller. Various finishing strategies provide different optimization path distribution and tool inclination calculation methods for tasks. Similarly, the five axis impeller machining also supports the four axis mentioned above and the manual setting of tool tilting and other functions.

Five axis impeller machining point is to use the tool point contact method to process the blade surface with continuous and spiral circular action. In this method, a variety of machining modes and feeding strategies are provided to adapt to different tasks, such as the cavity mode of five axis impeller machining to reduce the vibration of adjacent blades. The strategy also supports the four axis and manual tool tilting functions mentioned above.

Five axis impeller machining is a kind of typical free-form surface parts. If the traditional cam machining strategy is adopted, different machining directions need to be tested repeatedly, and the paths of different directions need to be connected through human intervention, which will take a lot of time to adjust. Traditional machining methods are time-consuming and difficult to ensure accuracy. HyperMILL? Provides professional machining modules for both open and closed five axis impeller machining, so that even users with less experience in machining can program NC programs of this kind of parts which are difficult to complete by using conventional programming strategy in a short time through simple settings. This specialized module is commonly used in various fields of five axis impeller processing.

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CNC computer gong processing tool

The work of determining the tool path is the focus of machining programming. Because the tool path of finishing cutting program is basically carried out along the contour sequence of parts, the main content is to determine the tool path of rough machining and empty stroke. Tool path generally refers to the path that the tool moves from the tool setting point until it returns to the point and ends the machining program. It includes the path of cutting and the non cutting empty stroke such as tool introduction and cutting out.

The shortest tool path can save the execution time of the whole machining process, and also reduce some unnecessary tool consumption and the wear of the sliding parts of the feed mechanism of the machine tool. The following figure 1 shows three taper turning methods, which are processed with rectangular circular command to analyze the reasonable determination of tool path. This method is that after each feed, the moving path of the turning tool is parallel to the generatrix of the cone. With each feed, the z-phase size increases in a certain proportion, which is the same as the common turning method, so that beginners can understand it easily. The calculation method of Z-direction dimension is based on the formula C = D-D / L. If C is 1:10, it means that 1 mm is removed from diameter x and 10 mm is added to length Z. According to this ratio, it is easy to program, and can ensure the same turning allowance every time, so that the cutting is uniform. The taper angle turning method is to keep the z-direction dimension as the drawing dimension with each X-direction feed. The taper angle of each cut is changed, and only the last cut is the taper angle required by the drawing. This taper turning method does not need to calculate the Z dimension every time, but because of the same Z dimension in machining, the machining path is longer, and the cutting allowance is not uniform, which affects the surface size and roughness of the workpiece. It is generally suitable for the taper with short taper and small allowance. Step table processing cone method, this processing method is that each time the tool path is parallel to the axis of the workpiece, many small steps are processed, and the last turning tool moves along the bevel of the cone. This processing method needs to make a 1:1 scale diagram first, otherwise it is easy to turn the waste workpiece, because it is a step shape, so the allowance is not uniform, which affects the processing quality of the cone.

Obviously, in the above three cutting routes, if the starting point is the same, the parallel turning cone route is the most reasonable, which is commonly used in production. The analysis of part drawing is the primary work in the process preparation, which directly affects the preparation and processing results of parts. It mainly includes the following contents:

Analysis of the geometric conditions of machining profile: the main purpose is to deal with the unclear dimension and closed dimension chain on the drawing.

Analyze the dimensional tolerance requirements on the part drawing to determine the processing technology to control the dimensional accuracy, such as the selection of cutting tools and the determination of cutting parameters.

Analysis of shape and position tolerance requirements: for CNC machining, the shape and position errors of parts are mainly affected by the accuracy of machine tool mechanical motion pairs. In turning, if the direction of movement along the z-axis is not perpendicular to the axis of its main axis, the shape tolerance requirement of cylindricity cannot be guaranteed; if the direction of movement along the x-axis is not perpendicular to the axis of its main axis, the position tolerance requirement of perpendicularity cannot be guaranteed. Therefore, before programming, we should consider the relevant scheme of technical processing.

Analysis of the surface roughness requirements of parts, material and heat treatment requirements, blank requirements, the number of pieces requirements is also the process arrangement and the determination of the tool path are parameters that can not be ignored. In NC turning, the program runs through the whole process of parts. Because each person’s processing method is different, the programming is also different, but the ultimate goal is to improve the production efficiency of CNC lathe, so it is particularly important to choose the most reasonable processing route. This paper will analyze the programming method in NC turning from the details of determining the tool path and selecting the appropriate g command. According to each individual geometric element (i.e. straight line, oblique line, arc, etc.), the corresponding processing program is worked out, which constitutes each program of the processing program, i.e. program segment. In the process of programming, we always hope to process the parts with the least number of program segments, so as to make the program concise, reduce the probability of error and improve the efficiency of programming.

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Introduction of cam processing with computer gong

For the processing of camshaft and large crankshaft, we hope that the equipment has better controllability, multi-functional and flexible turn milling head, and strong anti-collision protection function. Generally, in addition to the advanced and stable CNC system, the static geometric accuracy should be reliable, stable and have a long retention. The dynamic positioning accuracy should be implemented according to the vdi3441 standard, especially exaggerating the acceptance and assessment of the repeated positioning accuracy PS. since the positioning accuracy and reverse clearance can be compensated by the CNC system, the repeated positioning accuracy is the manufacturing precision It can’t compensate for the combination of degree and transmission chain precision.

When machining slender shaft, it is required to be able to measure the bending degree in the middle of crankshaft during clamping, and compensate the center frame through the numerical control system. At the same time, it is required to realize the function of online measurement through the instrument during machining. The key points to be achieved in Camshaft machining are: the perpendicularity of the two outer faces of flange relative to the camshaft axis, the runout of flange is 0.02mm, and the distance between the two flanges is 0.02mm The position degree of two road holes relative to the axis of the boss on the same side, the coaxiality of one hole relative to the other, the dimensional accuracy of each cam profile, and the shape and position accuracy include the profile degree, the runout of the base circle relative to the axis of the boss at both ends of the camshaft, and the parallelism of the generatrix of the cam profile relative to the axis of the boss at both ends of the camshaft. Similarly, for the crankshaft connecting rod neck processing, it is necessary to maintain a number of requirements such as coaxiality and parallelism.

Generally, it doesn’t need a lot of complex process equipment. The parts with complex shape and high precision can be processed by programming. When the product is modified and the design is changed, as long as the program is changed, there is no need to redesign the tooling. Therefore, CNC lathe processing can greatly shorten the product development cycle, and provide a shortcut for new product development, product improvement and modification.

CNC lathe processing is mainly aimed at the characteristics of wood products processing industry, combined with the operating habits, using the Chinese character operation, easy to learn and use (primary school education can operate the CNC system), can process cylinder, cone, arc, spherical and other complex shapes of rotary wood parts, can be set flexibly at any time, quickly change the processing style, the processing batch of parts should be more than For various reasons, the pure cutting time only accounts for 10% – 30% of the actual working time when machining medium and small batches of parts on non CNC grinding machine by ordinary lathe and batch CNC lathe.

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CNC computer gong processing workpiece overcut

Computer gong processing has become an important development direction of modern processing, with high degree of automation, high processing accuracy and strong adaptability to parts, so it is widely used in modern machining. But CNC machining will also occur on the workpiece overcut phenomenon. Overcutting will directly affect the machining accuracy of the workpiece, and even lead to the scrapping of the workpiece.

Causes of workpiece overcutting in CNC machining:

Improper operation of the operator.
The cutting allowance is not uniform.
Improper cutting parameters.
The strength of the tool is not enough, too long or too small.

CNC machining workpiece overcutting solution:

Reasonable adjustment of cutting parameters, large allowance, corner rounding.
Using SF function of machine tool, the operator can fine tune the cutting speed to achieve the best cutting effect.
The principle of using a knife: big but not small, short but not long.
Add the corner cleaning procedure, the allowance should be as uniform as possible, and the allowance on the side and bottom should be the same.

CNC processing problems can not be as easy as ordinary machine tools can be manually adjusted, so we must pay attention to every detail of the processing process, careful consideration, strive to be accurate, avoid overcutting problems, do not waste, improve resource utilization. Novices often encounter the situation that the score is not accurate, sometimes they have to score more than ten times to be accurate. To this end, today I will introduce the reasons and solutions of inaccuracy in CNC machining.

Reasons for inaccurate CNC machining

The operator’s manual operation is not accurate, and the manual operation number is wrong.
There are burrs around the mold.
The center bar has magnetism.
The four sides of the mold are not vertical.

The solution to the inaccuracy in CNC machining is as follows:

The manual operation should be carefully checked repeatedly, and the points should be at the same point and at the same height as far as possible.
Deburring the periphery of the mould with oilstone or file, wiping it with rag, and finally confirming with hand.
Demagnetize the center bar before centring the mold (ceramic center bar or others can be used).
Check whether the four sides of the die are vertical (the verticality error is large, so we need to review the scheme with the fitter).

Points are not complex, according to the above method can operate several times, I hope to help you.

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Grinding method of CNC lathe

The structure of computer gong machining center is mainly composed of the following parts.

Basic components. It is the basic structure of the machining center, which is composed of bed, column and worktable. They mainly bear the static load of the machining center and the cutting load during machining, so they must have enough stiffness. These large parts can be cast iron or welded steel structural parts. They are the largest volume and weight parts in the machining center.
Spindle assembly. It is composed of spindle box, spindle motor, spindle and spindle bearing. The start, stop and speed change of the spindle are all controlled by the numerical control system, and the tool installed on the spindle participates in the cutting movement, which is the power output component of cutting.
Numerical control system. The CNC part of machining is composed of CNC device, PLC, servo drive device and operation panel. It is the control center to execute the sequence control action and complete the machining process.
Automatic tool changing system. It is composed of tool magazine, manipulator and other parts. When the tool needs to be changed, the numerical control system sends out a command, and the manipulator (or by other means) takes the tool out of the tool magazine and loads it into the spindle hole.
Auxiliary devices. It includes vortex sliding, cooling, chip removal, protection, hydraulic, pneumatic and detection system. Although these devices do not directly participate in the cutting movement, they play a role in ensuring the machining efficiency, machining accuracy and reliability of the machining center, so they are also indispensable parts of the machining center.

Tool grinding method of CNC lathe for high speed CNC machining posture and method of tool grinding of CNC lathe are as follows:

People stand on the side of the grinder to prevent the fragments from flying out to hurt people when the grinding wheel is broken;
The distance between the two hands holding the knife is released, and the two elbows are clamped at the waist to reduce the shaking when grinding the knife;
When grinding, the turning tool should be placed in the horizontal center of the grinding wheel, and the tool tip should be tilted up about 3 ° to 8 ° slightly. After the turning tool contacts the grinding wheel, it should move horizontally in the left and right directions. When the turning tool leaves the grinding wheel, it should be lifted up to prevent the grinding edge from being damaged by the grinding wheel;
When grinding the flank, the end of the cutter bar is deflected to the left by an angle of main deflection angle; when grinding the flank, the end of the cutter bar is deflected to the right by an angle of auxiliary deflection angle;
When sharpening the arc of the tool tip, the front end of the tool is usually held by the left hand as the fulcrum, and the rear end of the tool is rotated by the right hand.

The precautions for CNC lathe tool grinding are as follows:

Before grinding tools, first check whether the grinding wheel has cracks and whether the grinding wheel shaft nut is tightened, and use it after trial run, so as to avoid the grinding wheel breaking or flying out to hurt people.
Don’t use too much force on the sharpener, otherwise it will make the hand slip and touch the grinding wheel surface, resulting in industrial accidents.
Wear protective glasses when sharpening to avoid grit and iron filings flying into the eyes.
Do not stand in the direction of rotation of the grinding wheel when grinding, in case of accidents.
When grinding the small cutter head, the small cutter head must be installed on the cutter bar.
The clearance between the grinding wheel bracket and the grinding wheel shall not be greater than 3 mm. If it is too large, it shall be adjusted properly.

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CNC five axis computer gong processing quality components

Five axis machining is a mode of NC machining.

According to ISO, the right-hand rectangular coordinate system is used to describe the motion of CNC machine tools. The coordinate axis parallel to the spindle is defined as Z axis, and the rotation coordinates around x, y and Z axis are a, B and C respectively. The movement of each coordinate axis can be realized by the table or by the movement of the tool, but the direction is defined by the movement direction of the tool relative to the workpiece. Generally, five axis linkage refers to the linear interpolation movement of any five coordinates in X, y, Z, a, B and C.

In other words, five axis refers to x, y, Z three moving axes plus any two rotating axes. Compared with the common three-axis (x, y, Z three degrees of freedom) machining, five axis machining means that when machining the parts with complex geometry, the machining tools need to be able to locate and connect in the five degrees of freedom.

The machine tool used in five axis machining is usually called five axis machine tool or five axis machining center. Five axis machining is often used in aerospace field to process body parts, turbine parts and impellers with free-form surfaces. Five axis machine tool can process different sides of the workpiece without changing the position of the workpiece on the machine tool, which can greatly improve the processing efficiency of prismatic parts. Five axis machining center manufacturing technology features:

With the continuous development of mold manufacturing technology, some weaknesses of vertical machining center itself are more and more obvious. Dongguan high-speed computer gong processing, modern mold processing generally uses ball end milling cutter to process, ball end milling cutter brings obvious benefits in mold processing, but if the vertical machining center is used, its bottom surface linear speed is zero, so the bottom surface finish is very poor, if the five axis machining center processing technology is used to process the mold, the above shortcomings can be overcome.

The use of five axis machining center makes the workpiece clamping easier. There is no need for special fixture during processing, which reduces the cost of fixture, avoids multiple clamping, and improves the accuracy of mold processing. Five axis technology can reduce the number of fixtures.

In addition, because the five axis machining center can save a lot of special tools in processing, so it reduces the cost of tools. Five axis machining center can increase the effective cutting edge length of the tool, reduce the cutting force, improve the service life of the tool and reduce the cost. Using five axis machining center to process the mold can quickly complete the mold processing, fast delivery, better guarantee the processing quality of the mold, make the mold processing easier, and make the mold modification easier. In the traditional mold processing, the vertical machining center is generally used to complete the workpiece milling.

Machining center a machine tool, centralized milling machine, drilling machine, tapping machine and other equipment functions, it can reduce the number of enterprise machine tools, because one person can operate multiple machining centers at the same time, reduce the operator, labor costs correspondingly reduced; in addition, it has a CNC machining center.

Five axis machining center has strong adaptability and good flexibility. The machining center can easily carry out multiple different processing procedures for box parts, such as drilling, reaming, reaming, boring, tapping, milling end face and trenching, so it can process parts with complex contour shape or difficult to control size, such as fan blade, automobile engine box and so on.

Five axis machining center supporting fixture stiffness, machining center’s own stiffness and accuracy maintenance requirements are very high; machining center technology is complex, and has high requirements for use, maintenance and management; machining center has a large one-time investment, and needs to be equipped with other auxiliary devices, such as CNC tool system. The operation and monitoring of CNC machining axis-0 are all completed in the control unit of CNC machine tool, which is the brain of CNC machine tool.

Compared with ordinary machine tools, CNC machine tools have the following characteristics:

High machining accuracy and stable machining quality;

It can carry out multi coordinate linkage and process complex parts;

When the machining parts are changed, generally only the NC program needs to be changed, which can save the production preparation time;

The machine tool itself has high precision, high rigidity, and can select favorable processing amount, with high productivity (generally 3-5 times of that of ordinary machine tool);

High degree of automation of machine tool can reduce labor intensity;

Five axis CNC machining requires higher quality of operators and higher technical requirements of maintenance personnel. CNC machine tools are generally composed of the following parts:

A. Host: it is the theme of CNC machine tools, including machine body, column, spindle, feed mechanism and other mechanical parts. It is used to complete a variety of cutting machinery.

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CNC lathe parts processing design

CNC processing and production design is based on the actual CNC processing technology level and production capacity of the enterprise, emphasizing the combination of design and CNC processing technology and production. Product design is not only graphic design, but also includes CNC processing technology design and production design. Production design should be mainly studied from the following aspects:

A. simplify the function or shape of parts;

B. maximize the standardization, generalization and serialization of products;

C. make the material grade, variety and specification specified in the design drawings consistent with the use of existing materials as far as possible;

D. combining the CNC machining process of computer gong with CNC machining process of computer gong more effectively;

E according to the CNC processing technology, operation rules and relevant information of the current normal production of the enterprise to judge the rationality of CNC processing technology design of the computer gong;

F select the dimension tolerance and surface roughness that can be guaranteed by mature CNC processing technology;

G comprehensive analysis of information related to the production process, the main parts of the necessary value engineering analysis.

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Application of CNC five axis computer gong processing

Five axis machining is a kind of machining center with high technology content and high precision, which is specially used for machining complex curved surface. This machining center system of five axis machining has a great influence on a country’s aviation, aerospace, military, scientific research, precision instruments, high-precision medical equipment and other industries. At present, five axis CNC machining center system is the only way to solve the problems of impeller, blade, marine propeller, heavy generator rotor, steam turbine rotor, large diesel engine crankshaft and so on.