2021 – Page 34 – CNC Machining & Turning, Milling, Metal parts

Classification of CNC computer gong processing

The common ones are classified by the following four methods.

Classification by process use

(1) General CNC machine tools. This kind of machine tools is the same as the traditional general machine tools. There are CNC turning, milling, boring, drilling, grinding machines, etc., and there are many kinds of each kind. For example, CNC milling machines include vertical milling, horizontal milling, tool milling, gantry milling, etc. The technological possibility of this kind of machine tool is similar to that of general machine tool, but the difference is that it can process complex shape parts.

(2) CNC machine tool center machine tool. This kind of machine tool is developed on the basis of general CNC machine tool. It is a kind of NC machine tool with automatic tool changing device (also called multi process NC machine tool or boring milling machining center, conventionally referred to as machining center) which is composed of a tool magazine (which can hold more than 10-100 tools) and automatic tool changing device on the general NC machine tool, which makes the NC machine tool further develop towards automation and high efficiency.

The difference between NC machining center machine tool and general NC machine tool is: after the workpiece is clamped once, the NC device can control the machine tool to automatically change the cutting tool, and continuously complete the milling (turning), boring, drilling, reaming, tapping and other processes on each processing surface of the workpiece. This kind of machine tools are mostly boring and milling, mainly used to process box parts. Compared with general NC machine tools, it has the following advantages

① Reduce the number of machine tools, easy to manage, for multi process parts as long as a machine can complete all processing, and can reduce the inventory of semi-finished products;

② Since the workpiece is clamped only once, the positioning error caused by multiple installation is reduced, and the machining quality can be guaranteed by the accuracy of the machine tool;

③ Process concentration reduces the auxiliary time and improves the productivity;

④ As the parts can be processed in multiple processes in one clamping on one machine tool, the number of special fixtures is greatly reduced, and the production preparation time is further shortened.

Due to the advantages of CNC machine tools, it is very popular with users, so it plays an important role in the production of CNC machine tools.

In addition, there is a kind of machining center, which is developed on the basis of lathe, with shaft parts as the main processing object. In addition to turning and boring, it can also drill, mill and tap any part of the end face and peripheral surface. This kind of machining center also has a tool magazine, which can install 4-12 tools. It is used to call this kind of machine tool turning center (TC).

(3) Multi coordinate CNC machine tool. Some complex shape parts can’t be processed with three-dimensional CNC machine tools, such as propeller, aircraft surface parts, etc. it needs more than three coordinate synthetic motion to process the required shape. Therefore, the emergence of multi coordinate CNC machine tools, which is characterized by the number of axes controlled by the CNC device is more, the structure of the machine tool is more complex, the number of coordinate axes usually depends on the processing requirements of parts. Now commonly used is 4, 5, 6 coordinate CNC machine tools. Figure 1 is the schematic diagram of five axis NC machining. At this time, the X, y, Z coordinates can be linked with the turntable rotation and tool swing at the same time to process wing and other parts.

According to the movement track classification of CNC machine tools

According to the relative motion path between the tool and the workpiece, the CNC machine tools can be divided into point control CNC machine tools, point line control CNC machine tools, contour control CNC machine tools, etc. It is described as follows:

(1) Point position control CNC machine tool. The numerical control device of this kind of machine tool can only control the moving parts of the machine tool to move accurately from one position (point) to another position (point), that is, it only controls the coordinate value of the end of the stroke, and does not carry out any cutting during the moving process. As for the moving speed and route between the two related points, it depends on the productivity. In order to have as high productivity as possible on the basis of accurate positioning, the movement between the two related points first moves to the new position quickly, and then decelerates by 1-3 levels to make it approach the positioning point slowly, so as to ensure its positioning accuracy. This kind of machine tool mainly includes CNC coordinate boring machine, CNC drilling machine, CNC punch machine and CNC measuring machine, and its corresponding CNC device is called point position control device.

(2) CNC machine tool controlled by point and line. When this kind of machine tool works, it is necessary to control not only the position (i.e. distance) between two related points, but also the moving speed and route (i.e. trajectory) between two related points. Its route is generally composed of straight lines parallel to each axis. It is different from the point control CNC machine tool in that when the moving parts of the machine tool move, it can cut along the direction of a coordinate axis (generally, it can also cut along a 45 ° oblique line, but it can not cut along a straight line with any slope), and its auxiliary functions are more than those of the point control CNC machine tool, for example, to increase the spindle speed control, cycle feed processing, cutting tool Selection and other functions. This kind of machine tool mainly has the simple numerical control lathe, the numerical control boring milling machine and the numerical control processing center and so on. The corresponding numerical control device is called point position linear control device.

(3) Contour control CNC machine tool. The control device of this kind of machine tool can continuously control two or more coordinate axes at the same time. When machining, it is necessary to control not only the starting point and the end point, but also the speed and position of each point in the whole machining process, so that the machine tool can process complex shape parts that meet the requirements of the drawing. Its auxiliary functions are also quite complete.

This kind of machine tools mainly include CNC lathes, CNC milling machines, CNC grinding machines and electrical machining machines. The corresponding numerical control device is called contour control device (or continuous control device).

According to the control mode of servo system

CNC machine tools can be divided into open-loop and closed-loop according to whether there is a detection feedback device for the controlled quantity. In the closed-loop system, according to the position of the measuring device, it can be divided into full closed-loop and half closed-loop. Based on the open-loop system, an open-loop compensation CNC system is developed.

(1) Open loop control of CNC machine tools. In the open loop control, there is no feedback device

The signal process of numerical control device is unidirectional, so there is no system stability problem. Because of the unidirectional flow of the signal, it does not check the actual position of the moving parts of the machine tool, so the machining accuracy of the machine tool is not high, and its accuracy mainly depends on the performance of the servo system. The working process is: the input data is calculated by the numerical control device, the command pulse is distributed, and the controlled worktable is moved by the servo mechanism (the servo element is usually a stepping motor).

This kind of machine tool works stably, reacts quickly, debugs conveniently and maintains simply, but its control precision is limited. It is suitable for medium and small CNC machine tools with general requirements.

(2) Closed loop control of CNC machine tools. Because the accuracy of open-loop control can not meet the requirements of precision machine tools and large-scale machine tools, it is necessary to detect its actual working position. Therefore, the detection feedback device is added to the open-loop control CNC machine tools to detect the position of the moving parts of the machine tools at any time during processing, so as to make it consistent with the position required by the CNC equipment, so as to achieve high processing accuracy.

Classified by numerical control device

CNC machine tools can be divided into hard wire (part) CNC and soft wire (part) CNC according to the CNC devices that realize the control of CNC logic function.

(1) Hard wire numerical control (called ordinary numerical control, namely NC). The input, interpolation and control functions of this kind of CNC system are realized by integrated circuits or discrete components. Generally speaking, different CNC machine tools have different control circuits, so the universality of the system is poor. Because it is all composed of hardware, the function and flexibility are also poor. This kind of system was widely used before 1970s.

(2) Flexible wire numerical control (also known as computer numerical control or microcomputer numerical control, namely CNC or MNC). This kind of system uses medium, large scale and super large scale integrated circuits to form CNC device, or microcomputer and special integrated chip. Its main NC functions are almost completely realized by software. For different NC machine tools, only different software can be programmed, while hardware can be almost universal. Therefore, it has strong flexibility and adaptability, and is also convenient for mass production. Modular software and hardware improve the quality and reliability of the system. Therefore, modern CNC machine tools all use CNC device.

Repetitive production of CNC lathe

CNC CNC lathe processing repeatability of production parts: the use of CNC grinder process preparation time occupies a higher proportion. For example Process analysis and preparation, programming, first part adjustment and trial cutting, etc., the sum of these comprehensive working hours is often tens to hundreds of times of the working hours of a single part, but these CNC lathe work contents can be saved and reused, so a part is successfully trial produced on the CNC grinder, and then put into production repeatedly, the production cycle is greatly reduced, the cost is also less, and better results can be achieved The economic benefit of the project is very good.

It is required that the CNC grinding machine can achieve high precision, high quality and high efficiency grinding under the control of computer. Compared with special grinding machine, it can save a lot of special process equipment, has strong flexible manufacturing capacity and obtains better economic benefits. Compared with ordinary grinding machine, it can eliminate many artificial interference factors in the long process of complex processing, and has good precision consistency and interchangeability of processing parts, and high processing efficiency.

The parts processed by CNC lathe should be able to give full play to the process characteristics of multi process centralized processing of CNC grinder. When CNC grinder processes parts, the situation of grinding workpiece with grinding wheel is exactly 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, ordinary grinder is mainly used for grinding cylindrical and circular CNC lathe In addition, it can also grind torus and complex combination surface of various forms.

The processing batch of the parts should be larger than that of the ordinary lathe to the batch CNC lathe. When the medium and small batch parts are processed by the non CNC grinder, due to various reasons, the pure cutting time only accounts for 10% – 30% of the actual working hours. When machining on the CNC grinding machine with multiple working procedures, such as grinding center, the proportion may rise to 70% – 80%, but the working hours for preparing to adjust are often much longer, so it will become uneconomic if the batch size of parts is too small.

CNC CNC lathe processing of some special parts to consider, there are some parts, although the processing batch is very small, ordinary lathe, but the shape is complex, high quality, good interchangeability, which can not meet the above requirements on non CNC grinder, can only be arranged to CNC grinder processing, such as parabola, cycloid cam and special surface mirror, etc.

CNC computer gong processing range

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

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 impeller is commonly used in aero-engine compressor, air compressor, marine underwater propeller and so on. In addition to the characteristics of general curved surface machining, it also has many special machining difficulties, such as narrow channel, easy tool to curve with the machined surface and adjacent.

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 on the same direction surface.

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.

CNC processing technology in mobile phone

First generation iPad let more people know CNC technology

The first generation iPad, released on January 28, 2010, quickly won the market. In addition to its high performance, the back shell process of CNC processing technology is also one of the highlights. Its color is still “high value” in its shape, which is liked by more consumers. It can be said that the adoption of iPad generation CNC technology will let more people know about the technology.

The first generation iPad sold high-precision and high complexity polishing CNC process back shell, which is a lot of “bonus”. The first generation iPad was initially applied to the fuselage thickness of 13.4mm, and the first generation iPad fuselage thickness of 13.4mm. CNC molding technology combined with magnesium alloy material back shell brings a strong metal texture to the product. Although from our current perspective, the thickness of the fuselage is somewhat unsatisfactory, but in terms of the background at that time, its technology has just been applied to flat products, it is not easy to achieve this.

The thickness of the first generation iPad is 13.4mm, and its technology is not so perfect. It focuses more on the appearance and interior without too much design. At the beginning of the design, the main focus of the iPad generation CNC back shell is the appearance. When holding, the body is smooth, but there is just the right grain feeling, which makes it feel better when playing with the product. In addition, the round corners around the back shell increase its portability and give people a great visual experience.

In terms of internal design, the internal performance of the first generation iPad back shell is relatively rough, the internal screw fixation method and “baffle” design are relatively abrupt, and the overall design of the back shell is poor. However, the existence of its stripe design can better provide space for components and ensure the performance of the product. The thickened design at the key position of the back shell can ensure the fixation of its function keys to a certain extent.

In addition, the internal screw fixation method and “baffle” design of the iPad with CNC process are relatively abrupt. It can be seen that the preliminary CNC process applied to the flat products is relatively rough, and there are still many areas for improvement in the internal design. However, the strict product precision and outstanding texture make the process superior to the injection molding and stamping molding processes. Of course, this is only the initial CNC process. What progress has this process made? Let’s go on.

CNC processing technology tends to be mature. Both Nokia N1 and iPad air2 adopt this technology. With the development of CNC technology, more and more tablet products are applied. The most representative ones are Apple’s latest series of tablet iPad air2 and Nokia N1 tablet computer. The back case of these two products adopts CNC technology. What are the improvements in technology and design?

Nokia N1 adopts the latest CNC process back shell, which makes the appearance more beautiful. In appearance, the products made by this process are more “slim”. The back shell gives people an overall sense of visual impact, and the appearance of the products becomes more exquisite (of course, this has a lot to do with the upgrading and improvement of the screen). The borders around the products become more rounded, which is not a rigid “frame” design, It’s more comfortable to hold it in hand. This change can be said to be a big improvement in technology.

The Nokia N1’s peripheral borders become more rounded, rather than rigid “frame” design. In addition, there are certain improvements in the details of the key position, so that the key position does not stay on the side border, but to a certain extent close to the backplane. In this way, the thickness of the body will not affect the user’s operation, which can be said to kill two birds with one stone. The realization of the design, to a certain extent, also depends on the improvement of the process.

The details of the key position have also been improved, which is easy to operate and more beautiful at the same time. The concave design of the interface has also been improved in the previous technology. There is a certain gap between the two key positions. The design makes the volume key position and the shutdown key position adjacent, which makes the side of the machine more beautiful.

The precision of CNC technology perfectly supports the design. We can see that the appearance of today’s CNC technology has been greatly improved compared with before. The round frame, the appearance is more refined, and the polishing process is more mature. The high-precision polished fuselage will have a kind of aesthetic feeling of industrial design. And these are only the improvement of appearance technology, so does the internal technology of back shell also have a qualitative improvement? Please go on to see.

The design is more reasonable while the interior design is beautiful. Compared with the exterior of the back shell, the improvement of the interior of the CNC back shell is more attractive to the author. Now the interior of the CNC back shell has become “clean” and the screw fixing place has become “small”. The position is close to the frame, which does not give people a sudden feeling of design. The overall design has been greatly improved.

How to operate computer gong processing

Generally, the workpiece processed by computer gong has complex shape, many processes, and many kinds of cutting tools. It is often necessary to complete the whole process from rough machining, semi finish machining to finish machining after one clamping. So the program is complicated. The following problems should be considered when programming.

Carefully analyze the drawings and determine the reasonable process route.
The size of the tool should be selected, and the measured actual size should be filled in the tool card.
Determine the reasonable cutting parameters. It mainly includes spindle speed, back feed, feed speed, etc.
There should be enough space for automatic tool change to avoid collision with workpiece or fixture. It is recommended to set the tool change position at the origin of the machine tool.
In order to check and debug the program, the processing contents of each step can be arranged in different subprograms, and the main program mainly completes tool change and subroutine call. This procedure is simple and clear.
Check and trial run the programmed program, and pay attention to whether there is interference among tools, fixtures or workpieces. When checking m, s and t functions, it can be carried out in the z-axis locking state.

Performance of computer gong deep hole drilling machine

The deep hole drilling machine with computer gong is different from the traditional way of hole processing. It mainly relies on specific drilling technology (such as gun drill, BTA drill, jet suction drill, etc.), and the special machine tools for drilling deep hole series and precision shallow holes with length diameter ratio greater than 10 are collectively referred to as deep hole drilling machine.

Deep hole drilling machine has the following five characteristics in practical application

The casting of the whole machine is made of high quality mihanna cast iron, which has been aged to make the casting structure uniform and stable, with high rigidity and good stability.
The 3-axis deep hole drilling machine adopts imported high rigidity, high speed CNC to process high-precision screw rod, which can provide more powerful torque and more durable during processing.
The high-quality servo motor and driver are used for the three-dimensional feed drive, and they are directly connected with the ball screw. The mechanical parts are processed, and the transmission is stable without back clearance. At the same time, its good rigidity and optimized shock absorption performance greatly improve the dynamic rigidity of the transmission system, and can realize rapid movement.
The spindle adopts powerful motor, which can meet the needs of high and low speed processing. CNC processing and automatic oil cooling system ensure the constant temperature during processing.
The operating system adopts Taiwan system, which can be compatible with CAD / CAM software

Processing and development of precision mould

Research on key technology of design and manufacture of continuous fine blanking die for complex parts

The continuous fine blanking die for complex parts is the frontier basic technology of fine blanking technology, and it is expected to promote the whole fine blanking technology in China. Taking the synchronizer gear ring, clutch plate, longitudinal compound continuous fine blanking process and continuous fine blanking die for complex parts as the breakthrough point, the key technology of fine blanking die design and manufacturing is studied, so as to realize the rapid improvement of fine blanking die technology in China and shorten the gap with advanced countries as soon as possible.

Study on the life promotion of fine blanking die and its related key technologies

Die life is a comprehensive reflection of die material, process and supporting product level. Taking die life of fine blanking as the leader to carry out technical research can not only solve the problem of low die life which is urgently needed in China, but also drive the technological development of die material, fine blanking process, supporting tooling and other auxiliary products.

Research and development of fine blanking precision forging composite technology

Precision blanking and precision forging are two advanced manufacturing technologies developed in parallel. If the precision blanking parts are too thick and need precision forging, the precision forging must be too thin. They are closely related. The basic idea of developing precision forging and fine blanking compound process is to find the combination point of the two processes (such as gear parts with wheel hub and cam parts with short shaft). The precision forging in China has a long history and has a high level, so it is a good way to improve the overall level of precision blanking technology in China.

Material selection and heat treatment of CNC computer gong

The first step of CNC lathe processing is to determine the technical requirements of parts and the batch of processed workpieces, formulate the functions that CNC lathe should have, make preparations in the early stage, reasonably select the conditions of CNC lathe, and satisfy the technical requirements of typical parts. The technical requirements of typical parts are mainly the structural dimension, processing range and accuracy requirements of parts. The control accuracy of CNC lathe is selected according to the accuracy requirements, that is, the requirements of scale accuracy, positioning accuracy and surface roughness of workpiece.

Lathe processing is a part of mechanical processing. There are mainly two processing methods: one is to fix the turning tool to process the unformed workpiece in rotation, and the other is to fix the workpiece to process the precision through the high-speed rotation of the workpiece and the lateral and longitudinal movement of the turning tool (tool holder). In the lathe can also be used to drill, reamer, reamer, tap, die and knurled things such as the corresponding processing. Lathe is mainly used to process shaft, disc, sleeve and other workpieces with reverse appearance. It is the most widely used machine tool in machinery manufacturing and repair factory.

There are several points in machining tools

The reasonable or unreasonable selection of machining skills will directly affect the machining accuracy, output power and economic benefits of the workpiece. The selection of technical equipment should be based on local production type, detailed processing conditions, workpiece structure characteristics and technical requirements.

Selection of fixture.

For single piece and small batch production, all kinds of general fixtures and machine tool accessories should be selected, such as chuck, flat vise for machine tool, division number one; for large-scale and large-scale production, special high-efficiency fixtures should be selected to improve the production rate; adjustable fixtures or group fixtures can be selected for multiple types of medium and small batch production.

Selection of cutting tools

Standard cutting tools are usually preferred. If mechanical convergence is selected, various efficient special tools, compound tools and multi edge tools can be selected. The type, standard and accuracy level of the cutting tool should be suitable for the machining request.

Selection of measuring tools.

General measuring tools, such as vernier caliper, micrometer and dial indicator, should be widely used for single piece and small batch production; limit gauge block and efficient special inspection fixture and gauge should be used for large-scale and large-scale production. It is necessary to adapt the accuracy of measuring tools to the machining accuracy.

The selection of the best span l of the spindle and the supporting span l of the spindle. The distance between the front bearing point of the spindle and the rear bearing point of the spindle is called span L. The support span of the spindle assembly has a great influence on the stiffness of the spindle itself and the support stiffness.

(1) Spindle bore diameter. The diameter of the inner hole of the spindle is used to fix the tool through the tool clamping device, drive the pneumatic or hydraulic chuck, etc. The larger the diameter of the spindle, the lighter the relative weight of the spindle components. The aperture size of the spindle is mainly restricted by the stiffness of the spindle.

(2) Spindle diameter. The larger the diameter of the spindle is, the higher its stiffness is, but the size of the bearing and other parts on the shaft increases accordingly. The larger the diameter of the bearing is, the larger the tolerance value of the bearing with the same grade accuracy is, and the more difficult it is to ensure the rotation accuracy of the spindle.

The determination of the spindle overhang a of CNC machining center, the spindle overhang a refers to the distance between the action point of the radial support reaction force of the front support of the spindle and the front end of the spindle, which has a great influence on the stiffness of the spindle assembly. According to the analysis and experiment, shortening the overhanging amount can significantly improve the stiffness and vibration resistance of the spindle assembly. Therefore, on the premise of meeting the structural requirements, the overhanging amount a should be shortened as much as possible.

CNC machining center spindle span diagram, discusses the structure design and progress of CNC machining center mechanical spindle, the influence of span L on the comprehensive stiffness K is not unidirectional. If l is larger, the deformation of the spindle is larger; if l is smaller, the deformation of the bearing has a greater impact on the displacement of the front end of the spindle. Therefore, l has an optimal value. If l is too large or too small, the comprehensive stiffness will be reduced. There is an optimal span l0 for the support span of the spindle, which can minimize the displacement of the front end of the spindle assembly. Due to the structural limitation and the guarantee that the center of gravity of the spindle assembly falls between the two supports, the actual support can be greater than the optimal support span.

Material selection and heat treatment of CNC machining center spindle

When the main shaft bearing of CNC machining center adopts rolling bearing, the journal can not be hardened. However, in order to improve the contact stiffness and prevent knocking from damaging the matching surface of the journal, many 45 steel main shaft journals are still subject to high-frequency quenching. When using sliding bearing, in order to reduce wear, the journal surface must have high hardness. Therefore, high frequency quenching is usually carried out at the journal; flame quenching can also be used for large diameter spindle to improve its surface hardness; 15 or 20 steel can be used for spindle with large impact, and carburizing, quenching and tempering can be carried out on the journal surface. 45 steel, GCr15, etc. are often used for spindle materials, which need nitriding and induction hardening.

The selection of spindle material is mainly based on the stiffness, load, wear resistance, heat treatment deformation and other factors. The stiffness of the spindle of CNC machining center is related to the elastic modulus E of the material, and the E value of the steel is larger, so the steel should be considered first. Moreover, the value of elastic modulus E of steel has nothing to do with the type of steel and heat treatment method. Therefore, the cheap medium carbon steel should be selected first. Alloy steel should be considered only when high load and large impact or when material deformation is reduced and high strength and wear resistance are required

The nature of CNC computer gong processing

High reliability

The reliability of CNC machine tool is a key index of product quality. Whether the CNC machine tool can play its high performance, high precision and high efficiency, and obtain good benefits depends on its reliability.

CAD design and modular structure design of CNC lathe

CAD can not only replace the manual to complete the tedious drawing work, but also can select the design scheme, analyze, calculate, predict and optimize the static and dynamic characteristics of the whole machine, and can simulate the working parts of the whole machine dynamically.

High speed and high precision

Linear motor has high driving speed, good acceleration and deceleration characteristics, superior response characteristics and tracking accuracy. By using linear motor as servo drive, the ball screw as an intermediate transmission link is eliminated, the transmission clearance (including reverse clearance) is eliminated, the motion inertia is small, the system has good rigidity, and the precision positioning can be achieved at high speed, thus greatly improving the servo accuracy.

The linear rolling guide pair has very good thermal stability because of its zero clearance in all directions and very small rolling friction, small wear and negligible heating, which improves the positioning accuracy and repeated positioning accuracy in the whole process. Through the application of linear motor and linear rolling guide pair, the fast moving speed of the machine tool can be increased from 10 ~ 20m / MIM to 60 ~ 80m / min, and the maximum speed can reach 120m / min.

High speed and precision is the eternal goal of machine tool development. With the rapid development of science and technology, the upgrading speed of mechanical and electrical products is speeding up, and the requirements for the machining accuracy and surface quality of parts are becoming higher and higher. In order to meet the needs of this complex and changeable market, the current machine tools are developing in the direction of high-speed cutting, dry cutting and quasi dry cutting, and the machining accuracy is constantly improving. On the other hand, the successful application of motorized spindle and linear motor, ceramic ball bearing, low-temperature and high-speed ball screw pair with high-precision and large lead hollow internal cooling and ball nut strong cooling, and linear guide pair with ball retainer and other machine tool functional parts have also created conditions for the machine tool to develop towards high speed and precision.

CNC lathe adopts motorized spindle, cancels belt, pulley, gear and other links, greatly reduces the moment of inertia of the main drive, improves the dynamic response speed and working accuracy of the spindle, and thoroughly solves the vibration and noise problems of belt and pulley when the spindle runs at high speed. With the motorized spindle structure, the spindle speed can reach more than 10000 R / min.

Machining path refers to the movement path and direction of the cutter relative to the part in the process of NC machining.

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

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

At present, under the condition that the CNC lathe has not been widely used, the excessive allowance on the blank, especially the allowance with forging and casting hard skin, should be arranged on the ordinary lathe. If must use the numerical control lathe processing, then needs to pay attention to the program flexible arrangement.

Key points of fixture installation: at present, the connection between hydraulic chuck and hydraulic clamping cylinder is realized by pull rod.

Reasonable selection of cutting parameters

For high efficiency metal cutting, the processed materials, cutting tools and cutting conditions are the three major elements. These determine the processing time, tool life and processing quality. The economic and effective machining method must be reasonable selection of cutting conditions. The three elements of cutting conditions: cutting speed, feed and cutting depth directly cause tool damage. With the increase of cutting speed, the temperature of tool tip will rise, which will produce mechanical, chemical and thermal wear. If the cutting speed is increased by 20%, the tool life will be reduced by 1 / 2.

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

Regular and stable wear is the ideal condition. However, in the actual operation, the selection of tool life is related to tool wear, dimension change, surface quality, cutting noise, processing heat and so on. In determining the processing conditions, it is necessary to study according to the actual situation. For stainless steel and heat-resistant alloy and other difficult to machine materials, you can use coolant or choose a rigid blade.

Reasonable selection of cutting tools

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

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

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

Reasonable selection of fixture

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

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

Processing principle of CNC computer gong

CNC processing is specialized in mechanical processing. With many years of practical experience, I would like to talk about the specific processing principles of mechanical processing

(1) In order to ensure the machining accuracy, rough and finish machining should be carried out separately. Because of the large amount of cutting during rough machining, the cutting force and clamping force on the workpiece are large, the heat value is large, and there is a significant work hardening phenomenon on the machined surface. There is a large internal stress in the workpiece. If rough machining and rough machining are carried out continuously, the precision of the parts after finish machining will be quickly lost due to the redistribution of stress. 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.

(2) Reasonable selection of equipment. Rough machining is mainly to cut off most of the machining allowance, and it does not require high machining accuracy, so rough machining should be carried out on the machine tool with high power and low accuracy, while finish machining requires high accuracy. High speed computer gong rough and finish machining in different machine tools, not only can give full play to the equipment capacity, but also can extend the service life of precision machine tools.

(3) Heat treatment process is often arranged in CNC machining process. 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. Mechanical parts processing to eliminate internal stress, such as aging treatment, quenching and tempering treatment, generally arranged after rough machining, before finishing. In order to improve the mechanical properties of parts, such as carburizing, quenching, tempering, etc., it is generally arranged after machining. If there is large deformation after heat treatment, the final processing procedure must be arranged.

Industrial control aluminum panel processing

Understand the shape, structure and corresponding graphic position of parts.
Look at the benchmark of the parts. Axis line, hole center line, surface, etc.
Look at important dimensions, accuracy, roughness, form and position tolerance, etc.
Look at the technical requirements, materials, etc.
Look at the three views, left view, right view, top view, section view, detail drawing, etc. to understand the outline structure and facilitate cutting.
Focus on the tolerance accuracy requirements of machining, including roughness, etc.
Heat treatment and hardness requirements in technical requirements.

Pay attention to tolerance, fit tolerance, finish and concentricity