chengcg – Page 41 – CNC Machining & Turning, Milling, Metal parts

Computer gongs processing – Requirements for CNC clamps

CNC milling machine is generally suitable for various types and small and medium-sized batch production. In order to clamp workpieces of different shapes and sizes, the fixture processed by CNC milling machine should be flexible, and the workpieces of various shapes and sizes can be clamped by proper adjustment. The special fixture of CNC milling machine has four functions: positioning, clamping, guiding and tool setting. The CNC machine tool is usually equipped with touch test head, tool presetting instrument and tool setting parts.

The precise positioning accuracy controlled by the program on the CNC machine tool can complete the tool guiding function in the fixture. Therefore, the fixture in NC machining usually does not need the function of orientation and tool setting, only needs the function of positioning and clamping, which can meet the needs of use.

(1) NC machining fixture should be able to use pneumatic, hydraulic, electric and other active clamping equipment to clamp quickly, so as to shorten the auxiliary time and provide the efficiency of NC machining.

(2) CNC milling machine model is used to NC multi-faceted processing. To prevent the fixture layout including the components on the fixture from interfering with the tool motion track, the fixture layout should not hinder the tool from multi-faceted machining of various parts of the workpiece.

(3) The fixture itself should have enough rigidity to adapt to large cutting parameters. Numerical control machining has the characteristics of process convergence. In one clamping of workpiece, it is necessary to carry out rough machining with large cutting force and finish machining to meet the demand of precision at the end of the workpiece. Therefore, the stiffness and clamping force of the fixture should meet the demand of large cutting force.

(4) The positioning of the fixture should be firm, the positioning elements should have high positioning accuracy, and the positioning position should be convenient for chip removal without chip accumulation. If the positioning surface of the workpiece is too small, the technical boss or auxiliary datum can be added.

(5) For the type of CNC milling machine, the minimum clamping deformation shall be ensured for the workpiece with small stiffness,

For example, make the clamping point close to the supporting point and prevent the clamping force effect on the hollow area of the workpiece. When rough machining and finish machining are finished in the same process, if the above methods can not control the workpiece deformation within the range of machining accuracy requirements, the program shall be suspended before finishing, and the operator shall change the clamping force (properly reduced) before finishing after rough machining, so as to reduce the influence of clamping deformation on machining accuracy.

Numerical control milling machine is a kind of machine tool which integrates digital control system on ordinary milling machine, and can carry out milling more accurately under the control of program code. It has the following features:

Parts processing has strong adaptability and flexibility, and can process parts with extremely disordered shape or difficult to control scale, such as mold parts, shell parts, etc;
At present, the pulse equivalent of CNC equipment is usually 0.001mm, and the high-precision CNC system can reach 0.1 μ M. in addition, the CNC machining also avoids the operator’s error;
It can process the parts which are difficult to machine or cannot be processed by machine tools, such as the disordered curve parts described by mathematical model and the three-dimensional curved surface parts;
It can process parts that need to be processed in multiple processes after one clamping and positioning;
With high production efficiency, CNC milling machine usually does not need to use special fixture and other special process equipment. When replacing the workpiece, it only needs to call the processing program stored in the CNC equipment, clamp things and adjust tool data, thus greatly shortening the production cycle. Secondly, CNC milling machine has the functions of milling machine, boring machine and drilling machine, so that the process is highly concentrated and the production power is greatly improved. In addition, the spindle speed and feed speed of CNC milling machine are stepless, so it is helpful to select the best cutting parameters;

What is CNC machine tool

CNC milling machine is the abbreviation of digital control machine tool, which is an automatic machine tool equipped with program control system

The control system can process the program with control code or other symbol instructions logically, decode it, express it with coded number, and input it into CNC device through information carrier. After calculation and processing, the CNC device sends out various control signals to control the action of the machine tool. According to the shape and size required by the drawing, the parts can be processed automatically.

Similarities and differences between machining center and CNC milling machine:

Like CNC milling machine, machining center is also composed of CNC system, servo system, mechanical body, hydraulic system and other parts.

But machining center is not the same as NC milling machine. The biggest difference between machining center and NC milling machine is that machining center has the function of automatic tool exchange. By installing different tools in the tool magazine, they can pass through in one clamping. In addition, the machining range of the two is different. The functions of machining center include milling workpiece, drilling workpiece, setting space, etc The machine can only mill the workpiece. The automatic tool changing device can change the cutting tool on the spindle to realize the functions of drilling, boring, reaming, tapping and grooving.

CNC machine tools, machining centers, is a kind of high precision, high efficiency automatic machine tools. It has a wide range of processing properties, and can process straight line cylinder, oblique line cylinder, circular arc and various threads. It has various compensation functions of linear interpolation and arc interpolation, and has played a good economic effect in the mass production of complex parts.

Five skills of CNC engraving machine

As we all know, engraving skill is an art that has been spread since ancient times, but with the rapid growth of economy in China, it is no longer only relying on hand to complete.

Next into the world of CNC engraving machine.

Skill 1:

The main shaft of CNC engraving machine, as a focus part, is mainly due to rust and blockage, which will cause the machine can not operate normally. The reason is that when we are in bad luck, the coolant in the coolant pipe is still left in it. In addition, the water also contains a large amount of elements. After high temperature, heavy water will gradually form. Heavy water contains a lot of impurities and precipitates After coming down, it will form dirt and form rust and blockage.

Therefore, the surface of motorized spindle should be coated with antirust oil and the cooling water should be changed regularly. And to prevent water temperature too high, but also to ensure the cleanliness of cooling water, if allowed, in case of spindle blockage.

Skill 2:

If the cooling system of the engraving machine is not grounded, the success rate will drop, the cold water head will fall off, and the service life will be greatly reduced. If the environment is severe, even the equipment deployment can not start things.

Skill 3:

If the fans and air ducts are not cleaned up, many smoke and dust inside will not be discharged. At this time, the lenses and laser tubes will also be seriously polluted. Finally, they will oxidize the electronic parts of the machine and cause the war is not good. This is why the response of engraving time is slow.

Skill 4:

Focus mirrors and mirrors should also be checked regularly. Because its frame is easy to heat, if not real-time disposal punishment, will make the appearance of oxidation, a long time will rust. Especially is the use of air pump and air compressor users, but also to regularly check the lens, so as not to cause irreparable place display.

Skill 5:

In order to make the engraving machine connected to the best state, to make its power cooling connection smooth, but also fair, the current should be connected within 50%, otherwise, it will cause the effect of increasing the rate of obstruction.

The most prominent feature of professional CNC carving machine is: professional carving CAD / CAM software and CNC carving machine for professional and strict matching!

When a professional computer (CNC) engraving machine is used for batch processing, the professional engraving software can ensure that the operator can make a plan smoothly and generate a reasonable and efficient processing program; when the data is loaded and the tool is adjusted and started to work, the operator only needs to listen to the cutting sound of the cutter on time to determine whether the tool is worn or not, and to replace the cutter when necessary, which is not necessary When the processing is completed, if it is found that the processing in some areas does not meet the requirements, the operator can use the repair function on the machine to make up for it on site, and a batch of work is completed so fluently. It’s easy to work like this!

The main performance is: tool adjustment is difficult to accurately locate and difficult to repair the deficiencies in the processing! This may be formed: low positioning accuracy of cutting tool affects the accuracy of products, and it is necessary to repeat processing to reduce processing power!

Taking professional carving CAD / CAM software as planning channel — the central computer (CNC) for efficient carving with small cutting tools usually carves out precise and disordered shapes. Its appearance and processing method are different from traditional CNC machining methods. If there is no professional carving CAD / CAM function as support, it is difficult to achieve high efficiency in practical application

Using precision high speed spindle motor

High speed and precision spindle motor features high speed, high precision, low noise, low vibration and high-speed constant power, which ensure that the small tool can obtain high cutting line speed, adhere to high rotation accuracy and stable working shaft system, and can produce satisfied high-speed cutting force.

CNC carving skills based on equal cutting skills

Equal cutting is a cam professional skill for high-speed carving of small tools. No matter how messy the processing area is, this skill can ensure the generation of a stable cutting amount and plan a reasonable carving way. Only the equal cutting method can ensure the efficient carving of small tools in terms of skills.

Safe and stable CNC control skills — the fundamental guarantee of efficient carving of small tools

CNC carving using small cutting tools, single cutting data removal is small, in order to improve the processing power, it is necessary to improve the average speed of feed, and can safely and quickly back. The safe and stable CNC control skills of the fine carving CNC system ensure that the small tool can receive stable cutting force and maintain a high and stable average feed speed in carving, so that the high power of small tool machining can be completed.

Stable mechanical structure — a solid channel for high speed carving with small cutting tools

The mechanical structure of the engraving machine is composed of all castings, and the moving guide rail is directly installed on the stable structure. Under the guarantee of high-precision machining parts and precise installation skills, it can ensure that the fine carving machine has good movement stability, low motion noise, provides a stable operation channel for high-speed machining of small cutting tools, and provides the completion of the motion method of “high-speed feed and quick return” A solid guarantee.

Useful function of repairing unexpected condition — to ensure that the machining of small tools is true and efficient

Because CNC engraving uses small tools to process, the unexpected situation that small tools wear quickly and break easily can not be completely changed. Therefore, the computer engraving machine is required to have a useful function of repairing unexpected conditions. The operator can repair the carving errors directly in the operation channel. Otherwise, once an accident occurs, it needs to be reprogrammed or processed from scratch, which will result in a lot of meaningless repetitive work The processing power is reduced.

Computer gong processing – tapping problem

Drilling, milling and tapping center machine is a kind of machining equipment which has different specifications of through-hole or blind hole in the shell, equipment end face, nut and other tools of CNC machine tool, and the thread, screw or thread are machined on the inner side of parts. Let’s first understand the characteristics of drilling and milling center machine.

The drilling, milling and tapping center machine is very simple when adjusting the model. The automatic reverse device can freely adjust the working stroke of the drilling and milling tapping center machine. The processing workpieces with shallow holes and holes can be easily adjusted. In the double installation device, the screw tap can be prevented from damage, and the spindle can be back and forth and up and down. The double safety clutch is specially designed for the advance and retreat of the cutter. The spindle can stop automatically and the tool will not be damaged by the reversing tool withdrawal. The gear of drilling and milling center machine matches with the pitch between the spindle and the spindle to promote complete matching, vertical stability, accuracy, and high precision. When the screw taps, it can move forward and backward without output. At the same time, it can be configured with multi axis synchronous processing, and the production efficiency will be greatly improved

It can also reduce and save labor: drilling, milling and tapping center machine combines tapping and stamping of parts into a process, which can be fully automated, thus saving labor costs. It can also reduce adverse effects. Accurate positioning of drilling and milling center machine can reduce the damage probability of taps. At the same time, it can also reduce the accurate positioning of drilling and milling center machine, and provide the probability of waste products caused by errors. So what are the common problems in the use of drilling milling tapping center machine? How to solve this problem? Well, today’s editor will help you solve these problems.

Breaking of drill tap

Solutions: when the tap of drilling and milling center machine is broken, the diameter of thread bottom hole should be correctly selected; the drilling depth of grinding edge angle or spiral groove tap should reach the specified standard; the cutting speed should be appropriately reduced and selected according to the standard; when tapping, correct the tap and bottom hole to ensure its coaxiality meet the requirements, and select floating tapping chuck; increase the tap The front angle, shorten the length of the cutting cone; ensure that the hardness of the workpiece meets the requirements, select the safety collet; the anti County tap wear should be replaced in time.

Tap tooth breakage

Solution: tap tooth chipping, properly reduce the tap front angle; appropriately increase the length of the cutting tap; reduce the hardness and replace the tap in time. If the tap is worn too fast, the cutting speed should be reduced properly; the front angle of the tap should be reduced to lengthen the length of the cutting cone; the cutting fluid with good lubricity should be selected; the workpiece to be machined should be properly heat treated; and the tap should be properly sharpened.

Excessive pitch diameter of thread

Solutions: if the pitch diameter of the thread is too large, select the tap pitch diameter with reasonable accuracy level; select the appropriate cutting fluid and reduce the cutting speed appropriately; correct the coaxiality of the tap and the bottom hole of the thread when drilling and milling the tapping center machine, and use the floating chuck; appropriately reduce the front angle and the back angle of the cutting tap; remove the burr generated by the grinding tap and appropriately increase the length of the cutting tap.

Too small pitch diameter of thread

In addition, it is necessary to increase the cutting accuracy of the tap and to select the proper cutting angle of the tap.

The surface roughness of thread is too large

Solution: if the surface roughness value of thread is too large, properly increase the front angle of the tap to reduce the cutting angle; conduct heat treatment to properly improve the hardness of the workpiece to ensure that there is a low surface roughness value on the front cutter surface of the tap; select the cutting fluid with good lubrication; appropriately reduce the cutting speed; replace the worn tap for the drilling and milling center machine.

Drilling, milling and tapping center machine is a kind of metal cutting equipment, of course, it can also drill holes, but from this name, we can see that it is also very aggressive. Well, after a simple understanding of the drilling and milling center machine, the next step is to analyze the current situation of the overall market.

The function of drilling, milling and tapping center machine is to drill the hole and tap together. From here, we can see that one of its characteristics is high efficiency, because it combines the two processes and completes it at one time.

In the absence of drilling and milling tapping center machine, we need to work together with drilling machine, lathe or manual wire drilling tools to complete what it has done now

CNC computer gongs hobbing

In the process of equipment design and manufacturing, manual calculation method was used, which was not only inefficient, but also prone to errors, and modern design methods could not be used, especially for local conjugate meshing gears such as spiral bevel gears and gears. Tooth design, process parameter selection, tooth contact analysis and stress-strain analysis are closely related, Such as mechanical optimization design, finite element analysis and Simulation of machining process, perfect application software and machine tools have become the necessary conditions for modern enterprise product development.

Here, we will introduce typical gear and metal materials.

Typical gear materials:

S45C (mechanical structure and carbon steel): S45C 0.45% carbon, medium carbon steel (steel). Gear, bevel gear, rack, bevel gear, worm gear use this material more.

SCM415 (chromium molybdenum alloy steel): low carbon alloy steel (C = 0.15%) represents the material. Generally speaking, after carburizing and quenching, the strength of the material after heat treatment is higher than that of S45C scm440. The service surface hardness is about 55 to 60.

Sus303 (Cr – 8 nickel steel stainless steel: 15): stainless steel, as the name implies, is not easy to rust steel (stainless steel). The austenitic stainless steel of the system is basically non-magnetic; the stainless steel gear is mainly used in the machinery which needs to avoid rusting, similar to sus303 and SUS304 stainless steel, and it is more corrosion resistant than sus303.

Casting copper alloy, casting copper alloy is the main material for manufacturing worm gear. Usually there is a phosphor bronze casting (cac502), aluminum bronze (cac702) and other meshing hands. Most of the materials used for worm meshing are S45C / scm440 / SCM415 steel, etc. Use different materials to prevent worm gear worm gear meshing tooth surface sliding agglutination and excessive wear due to etc.

Above is our original gear, typical gear selection material. CNC hobbing machine and ordinary lathe CNC lathe processing, but because of fixture, CNC hobbing, large and small modulus gear processing continuous automatic processing to complete all processes, should pay attention to the following aspects.

Choose reasonable cutting parameters

For metal processing, high efficiency, processing materials, cutting tools and cutting conditions are the three main factors. These determine the processing time, tool life and machining quality. The economical and effective treatment is to choose the cutting condition reasonably. Cutting conditions are three elements: cutting speed, cutting depth of the tool direct damage. With the increase of cutting speed, the temperature will rise, there are mechanical wear, chemical and thermal. If the cutting speed is increased by 20%, the tool life will be reduced by 1 / 2.

Back feed conditions and tool wear are kept to a minimum. But feeding is big, cutting temperature, wear. Large module gear processing. It is affected by the cutting speed of the tool. Although the cutting depth of the tool cutting speed and feed has no big impact, but in a small cutting depth and cutting, cutting material hardening layer, will also affect the tool life.

However, in practice, the selection of tool life, tool wear, machining size change, surface quality, noise, heat and related treatment is reduced. It is necessary to study according to the actual situation. Stainless steel and heat resistant alloy and other hard small modulus gear processing materials, can choose coolant or rigid blade.

Choosing the right tool for CNC gear hobbing

Thick selection of high strength, good durability tools to meet the rough turning depth, feed requirements.
Automobile, high selection accuracy, good tool durability, to ensure the machining accuracy requirements.
In order to reduce the conversion time and tool convenience, machine tools and blades should be used as much as possible.

Selection of fixture for CNC gear hobbing

In the special points of NC gear hobbing, general fixture should be used as far as possible, and special fixture should be avoided;
The coincidence of parts positioning datum reduces the positioning error.

Determination of machining route for special points of NC Gear Hobbing

The special points of NC Hobbing should be able to meet the requirements of machining accuracy and surface roughness;
CNC gear hobbing processing special place should try to shorten this process, reduce the travel time of the tool.

Contact machining allowance of machining line

At present, the conditions used are not in line with the popular CNC lathe, the edge should be too rough, especially for forging, casting hard pad placed in the ordinary lathe. If you have to use CNC lathe processing, pay attention to the flexible arrangement of the program. The following points: first, use the hydraulic clamping nut wrench to clamp the hydraulic cylinder, delete the slide, take out the spindle, and then manually chuck the fixing screw, which can unload the chuck.

Effective and reasonable turning

The comprehensive index of G200 turning center processing unit is modular, with high-power dual spindle and four axis linkage function, so as to further shorten the processing time. Work axis clamping means other concepts, on the other hand, the product uses an integrated intelligent processing unit to automatically clamp the workpiece position and treatment. In other words, automatic clamping does not affect other spindle machining, and a function can shorten processing time by about 10%.

In order to improve the accuracy and production efficiency

With the improvement of productivity level, users also have high precision. The tolerance of workpiece after machining by G200 turning center and cold start is + / – 6 mm. In the process of machining, it is usually 2 mm. Therefore, index company provides customers with complete solutions with high precision, high efficiency and high precision. It also provides solutions, which requires careful selection of spindle, bearing and other characteristics

Difference between fast wire and slow wire in NC WEDM

Fast wire in the professional terminology is called: high speed reciprocating wire EDM wire cutting machine

Slow wire is called low speed unidirectional WEDM in professional terms

The wire speed of reciprocating WEDM is 6-12 m / s. The biggest characteristic of the product is that it has 1.5 degree taper cutting function, and the processing thickness can be more than 1000 mm. It is used in all kinds of medium and low-grade mold manufacturing and special parts processing, and has become one of the most widely used machines in China’s CNC machine tools. However, due to the fact that the reciprocating WEDM machine can not implement constant tension control on the electrode wire, and the computer gong processing, the electrode wire jitters greatly and is easy to break in the process of processing. Because the electric grade wire is used repeatedly, it will cause electrode wire loss, machining accuracy and surface quality reduction.

The electrode wire of low-speed WEDM uses copper wire as tool electrode and generally moves unidirectionally at the speed of less than 0.2m/s. A pulse voltage of 60-300v is applied between the copper wire and the processed materials such as copper, steel or superhard alloy, and a gap of 5-50um is maintained. The gap is filled with insulating medium such as deionized water (close to distilled water), which causes spark discharge between the electrode and the workpiece This is consumed and corroded, and numerous small pits are etched on the surface of the workpiece. Through the monitoring and control of NC control and the execution of servo mechanism, the discharge phenomenon is uniform and consistent during the machining of mechanical parts, so that the processed products can be processed into products with the required size and shape accuracy. At present, the accuracy is up to 0.001mm, and the surface quality is close to the grinding level. The electrode wire is no longer used after discharge, and no resistance anti electrolysis power supply is adopted. Generally, it is equipped with automatic threading and constant tension device. It has the advantages of stable, uniform, small jitter, high machining accuracy and good surface quality, but it is not suitable to process large thickness workpieces. Due to the precise structure of the machine tool, high technology content, high price of the machine tool, the use cost is also high.

It can form plastic parts with deep holes and complex shapes.

Under heat and pressure, the plastic can be heated quickly and evenly through the mold pouring system to ensure short hardening time.

The dimensional accuracy of plastic parts is easy to ensure and the flash of parting surface is thin. It is difficult to extrude plastics with fluidity less than 80mm. The forming pressure is higher than that of the glue pressing method. The consumption of plastic must be increased (pouring part).

Injection method: the granular or powdered plastic is heated and melted into the flowing state in the barrel of the injection machine, and then the whole cavity is filled with a narrow nozzle and the pouring system of the mold with a very high pressure and poor speed. After a certain period of setting, the mold is opened, and the plastic parts can be taken out from the mold. The characteristics of injection molding: short forming cycle, easy to realize. The dimensional accuracy of plastic parts is easy to guarantee.

The mold is usually designed to be fixed. When there are many metal inserts in the plastic parts, the installation of the inserts is more difficult. Plastic mould can be divided into thermosetting plastic pressing mould, thermosetting plastic extruding mould, thermosetting plastic injection mould and thermoplastic injection mould.

According to the form of material cavity, thermosetting plastic pressing mold can be divided into:

(a) Open die, that is, the cavity is the feeding cavity;

(b) Semi closed die, that is, the cross section of the feeding chamber;

(c) The feeding cavity is the continuous part of the cavity, and the forming pressure is completely transmitted to the pressed plastic parts through the upper die.

According to the structure, it can be divided into:

(a) Mobile press mold,

(b) Fixed press mold.

Factors affecting the quality of EDM

There are many factors affecting the processing quality, which are related to the selection of electrode materials, electrode manufacturing, electrode clamping and alignment, the selection of machining standards and the appropriateness of operation process. To prevent the production of waste products, the following should be noted.

Correct selection of electrode materials

In cavity machining, graphite is a common electrode material. However, due to the variety of graphite, not all graphite materials can be used as electrode materials for EDM. Special graphite with high strength, high density and high purity should be used. Copper electrode is often used in precision. One is: the discharge end of EDM, which is used to process cavity, lettering, etc., and is usually made into the required shape. The material is graphite, copper or aluminum (rare). The other is: the discharge end of WEDM is made of molybdenum wire. Its principle is to apply high-frequency and high-voltage to the discharge end through the electric control part. When the electrode (molybdenum wire) contacts with the grounding end (workpiece), it will form high-frequency ignition and generate high temperature, which will quickly dissolve the workpiece surface (a very small gap) in contact with molybdenum wire, which is called wire cutting.

The so-called multi electrode machining refers to the parts to be processed with high precision, and the discharge parts should be discharged twice or more. In the early stage, it is rough discharge machining with larger translation, and the later is fine discharge machining with small translation.

Selection of processing materials for computer gongs

CNC precision machining engineers summarize their experience in actual machining, mainly including the following situations:

The tubular material will bend and deform when it is cut open;
When the center of the part is hollowed by WEDM, the stress and deformation will occur;
POM deforms due to excessive cutting amount or high processing temperature;
Customized materials have not been properly and scientifically aged;
Other complex parts in the process of processing due to improper process settings resulting in subsequent processing deformation;

In order to avoid the deformation caused by the above conditions in the processing, thus affecting the precision of the workpiece, the technical personnel put forward the following countermeasures:

Appropriate and scientific aging treatment should be carried out for customized materials and hollow materials;
The stress effect of each process should be considered in the processing of complex structural parts,

Set up scientific and reasonable process flow;

In the processing of POM and PVC materials, it is necessary to consider the particularity of materials, set appropriate machining allowance, and adopt the principle of “a small number of times” for processing and measuring;
The processing of curved surface needs to design and make good fixture,

Balance the clamping force on the workpiece;

CNC machining center structure can be divided into two parts: host part and control part! The host part includes the body, headstock, worktable, base, column, beam, feed mechanism, tool magazine, tool changer, auxiliary system, etc

The structure of CNC machining center is as follows

CNC machining center structure can be divided into two parts: host part and control part!

The host part includes the body, headstock, worktable, base, column, beam, feed mechanism, tool magazine, tool changer, auxiliary system, etc. the control part includes hardware part and software part

The hardware part includes: computer digital control device (CNC), programmable logic controller (PLC) input and output equipment, spindle drive device, display device, etc.

Software part includes: system program and control program two parts!

The purpose of the automatic tool changer is to meet the processing requirements,

The tool installed on the spindle is automatically replaced. The automatic tool changer is a set of independent and complete parts.

The tool changing process of the automatic tool changing device consists of two parts: tool selection and tool change!

Tool selection means that the tool magazine will automatically move the tool to be used to the tool change position according to the tool selection instruction. Tool change is to take down the used tool on the spindle and install the selected tool on the spindle!

Knowledge of using computer gongs

CNC computer gongs usually use vacuum chuck because the workpiece has high requirements for surface smoothness, or when the fixture of CNC computer gong itself cannot clamp the workpiece well, it is a relatively cheap special fixture in CNC machine tools.

Vacuum chuck used on CNC computer gongs: the vacuum chuck plays the role of fixture in CNC machining center. Some workpieces require high surface smoothness, so they can not use the fixture of common CNC computer gongs. At this time, the vacuum sucker can be put into use. However, we seldom use rubber vacuum cups in CNC computer gongs, but we use CNC vacuum cups more. The so-called CNC vacuum sucker is a kind of special vacuum sucker with vacuum generator and switch. The suction principle is the same as rubber vacuum chuck, which creates a vacuum environment to make the suction cup press on the workpiece under atmospheric pressure, but CNC vacuum chuck is the only one The vacuum environment is produced by the vacuum generator. The rubber vacuum chuck is a simple vacuum component, while the CNC vacuum sucker is like a large plate.

The computer gong machining of CNC machine tools is mainly used to process parts with complex shapes, but the structure of the fixtures used is often not complicated. The selection of fixture for CNC milling machine can be firstly determined according to the batch of production parts. For the single piece, small batch and heavy workload mold processing, the positioning and clamping can be realized directly on the machine table by adjusting, and then the position of the parts can be determined by setting the machining coordinate system.

What is CNC computer gong vacuum sucker: vacuum sucker, also known as vacuum spreader, is one of vacuum equipment actuators. Generally speaking, it is the cheapest way to grab the product with vacuum sucker. There are various types of vacuum suction cups. Rubber suction cups can be operated at high temperature. The suction cups made of silicone rubber are very suitable for grasping products with rough surface, while those made of polyurethane are very durable. In addition, in the actual production, if the sucker is required to have oil resistance, polyurethane, nitrile rubber or polymer containing vinyl can be used to make sucker. Generally, in order to avoid scratches on the surface of the products, it is better to choose the suction cup with bellows made of nitrile rubber or silicone rubber. The material of suction cup is made of nitrile rubber, which has large breaking force, so it is widely used in various vacuum holding equipment.

Machining is a process of changing the overall dimension or performance of the workpiece with processing machinery. According to the temperature state of the workpiece to be processed, it can be divided into cold working and hot working. Generally, it is processed at normal temperature and does not cause chemical or physical changes of the workpiece, which is called cold working. Generally, the processing above or below the normal temperature will cause the chemical or physical phase changes of the workpiece, which is called thermal processing. Cold working can be divided into cutting and pressure machining according to the difference of processing methods. Heat treatment, forging, casting and welding are common in hot working.

The machines needed for machining include digital display milling machine, digital display molding grinder, digital display lathe, EDM machine, universal grinder, machining center, laser welding, middle wire feeding, etc., which can be used for turning, milling, planing and grinding of precision parts. Such machines are good at turning, milling, planing and grinding of precision parts, and can process various irregular shape parts with the machining accuracy of 2 μ M

In addition, cold and heat treatment is often used in assembly. For example, during the assembly of bearing, the inner ring is often cooled in liquid nitrogen to shrink its size, the outer ring is heated properly to enlarge its size, and then it is assembled together. The outer ring of the wheel of the train is also sheathed on the substrate by heating, and the bonding firmness can be ensured when it is cooled (this method is still applied to the transfer process of some parts).

Mechanical processing includes: filament power winding, laser cutting, heavy processing, metal bonding, metal drawing, plasma cutting, precision welding, roll forming, sheet metal bending, die forging, water jet cutting, precision welding, etc.

Computer gong processing – machine failure

Fault analysis is the first step of machine tool maintenance. Through fault analysis, on the one hand, it can quickly find out the cause of the fault and eliminate the fault; at the same time, it can also play a role in preventing the occurrence and expansion of the fault. Generally speaking, the main methods of machine tool fault analysis are as follows:

Conventional analysis method conventional analysis method is a method of routine inspection on the mechanical, electrical, hydraulic and other parts of the machine tool, so as to determine the cause of the failure. On machine tools, conventional analytical methods usually include the following contents:

1) Check whether the specifications of power supply (including voltage, frequency, phase sequence, capacity, etc.) meet the requirements

2) Check whether the connection of CNC servo drive, spindle drive, motor and input / output signal is correct and reliable

3) Check whether the printed circuit board in CNC servo drive device is firmly installed and whether the connection part is loose

4) Check whether the setting end and potentiometer of CNC servo drive and spindle drive are correct

5) Check whether the oil pressure and air pressure of the hydraulic, pneumatic and lubricating parts meet the requirements of the machine tool

6) Check the electrical components and mechanical components for obvious damage, etc

The action analysis method is a method to determine the bad action position by observing and monitoring the actual action of the machine tool and trace the root cause of the fault. Generally speaking, the hydraulic and pneumatic control parts of the machine tool, such as: automatic tool change device, exchange table device, fixture and transmission device, can be determined by action diagnosis.

State analysis method state analysis method is a method to determine the cause of failure by monitoring the working state of the actuator. This method is most widely used in the process of machine tool maintenance. In modern CNC system, the main parameters of servo feed system, spindle drive system and power module can be tested dynamically and statically. These parameters include: input / output voltage, input / output current, given / actual speed, position, actual load condition, etc. In addition, the status of all input / output signals of CNC system, including internal relays and timers, can also be checked by the diagnostic parameters of CNC system. Through the state analysis method, the cause of failure can be quickly found out according to the internal state of the system without instruments and equipment. It is widely used in the process of machine tool maintenance, and the maintenance personnel must master it skillfully.

Operation and programming analysis method operation and programming analysis method is a method to confirm the fault cause through some special operation or compiling special test program section. For example, through manual single step to execute automatic tool change, automatic table exchange action, execute single function processing instructions and other methods to detect the action and function. By this method, the cause and components of the fault can be determined and the correctness of the program can be checked.

Self diagnosis of CNC system is a self diagnosis and testing method for the key hardware and control software of the system by using the internal self diagnosis program or special diagnosis software. It mainly includes boot self diagnosis, online monitoring and offline testing. Adjustment of machine tool accuracy and function,

Using precision level instrument and other detection tools, mainly by adjusting the pad iron way to fine adjust the level of the main bed of the computer gong processing machine tool, so that the geometric accuracy of the machine tool can reach the allowable tolerance range;
For the automatic tool change device, adjust the position of the tool magazine, manipulator, travel parameters, etc., and then check the action with the command, which is required to be accurate;
For the machine tool with APC automatic exchange table, after adjusting the relative position, carry out automatic load exchange;
After the adjustment of the machine tool, carefully check whether the parameter setting values in the numerical control system and the programmable controller conform to the data specified in the random index, and then test the main operation functions, safety measures, execution of common instructions, etc.

Computer gong processing – sheet metal

Purpose of sheet metal:

There are a lot of sheet metal materials suitable for stamping. Sheet metal materials widely used in electronic and electrical industry include:

⒈ the common cold-rolled plate SPCC refers to the continuous rolling of steel ingot into the required thickness of steel coil or sheet. SPCC surface without any protection, exposed to the air is very easy to be oxidized, especially in humid environment, oxidation speed is accelerated, dark red rust appears, the surface should be painted, electroplated or other protection.

The base material of SECC SECC galvanized steel sheet is a common cold-rolled steel coil. After degreasing, pickling, electroplating and various post-treatment processes in the continuous electro galvanizing production line, it becomes the electro galvanized product. SECC not only has the mechanical properties and approximate processability of general cold-rolled steel sheet, but also has superior corrosion resistance and decorative appearance. In the market of electronic products, home appliances and furniture, it is very competitive and replaceable. For example, SECC is widely used in computer cases.
Hot dip galvanized steel sheet SGCC hot-dip galvanized steel coil refers to the semi-finished products after hot-rolled pickling or cold-rolled, which are cleaned and annealed, immersed in the solution zinc bath at about 460 ° C, and the steel sheet is coated with zinc layer, and then quenched, tempered, leveled and chemically treated. SGCC material is harder than SECC material, with poor ductility (avoiding deep drawing design), thicker zinc layer and poor weldability.
The content of Cr (CR) in SUS301 is lower than that in SUS304, and its corrosion resistance is poor. However, after cold working, it can obtain good tensile strength and hardness, and has good elasticity. It is mostly used in spring spring and anti EMI.
Stainless steel SUS304 is one of the most widely used stainless steels. Because it contains Ni (nickel), it is more corrosion-resistant and heat-resistant than the steel containing Cr (CR). It has very good mechanical properties, no heat treatment hardening phenomenon and no elasticity.

2、 Features of sheet metal:

Sheet metal, B ǎ N J ī n (metal plate; Sheet metal in English) has not yet had a relatively complete definition. According to a definition in a foreign professional journal, it can be defined as: sheet metal is a comprehensive cold working process for sheet metal (usually less than 6 mm), including shearing, punching / cutting / compounding, folding, welding, riveting, splicing, forming (such as automobile body), etc. Its remarkable feature is that the thickness of the same part is the same.

Sheet metal has the characteristics of light weight, high strength, conductive (can be used for electromagnetic shielding), low cost, good mass production performance and so on. It has been widely used in the fields of electronic appliances, communication, automobile industry, medical equipment, etc., for example, in computer case, mobile phone, MP3, sheet metal is an essential part. With the application of sheet metal more and more widely, the design of sheet metal has become a very important part in the process of product development. Mechanical engineers must master the design skills of sheet metal parts, so that the designed sheet metal can not only meet the requirements of product function and appearance, but also make the stamping die manufacturing simple and low cost.

Sheet metal processing is the key technology that sheet metal technical staff need to grasp, and it is also an important process of sheet metal forming. Sheet metal processing includes the traditional cutting and blanking, blanking processing, bending and pressing forming and other methods and process parameters, as well as various cold stamping die structures and process parameters, various equipment working principles and operation methods, as well as new stamping technology and new technology. Parts sheet metal processing is called sheet metal processing.

What should we pay attention to when we look at the sheet metal processing plant.

The unfolded drawing of sheet metal processing plant is based on the part drawing

If there are mistakes (similar and asymmetric), it should be highlighted
Reasonable selection of clearance and hemming methods: clearance 0.3 below T = 2.0, 0.5 clearance between T = 2-3, and long edge wrapping with short edge (door panel)
The deployment method should be suitable, convenient, material saving and processability
Burr direction
Draw the sectional view according to the position and direction of tooth extraction, riveting, tearing and bumping
Check the material, plate thickness and plate thickness tolerance
The place to be protected by spraying must be indicated
Enlarge the drawing where the size is large
For special angle, the inner radius of bending angle (generally r = 0.6) should be tested and unfolded
Reasonable consideration of tolerance dimensions: negative difference goes to the end

CNC lathe processing

CNC machining classifies robots according to the motion track of CNC lathe

(1) Point control CNC lathe processing robot. The CNC lathe robot of CNC equipment can only control the moving parts of the lathe from one position to another accurately, that is to say, only the value of controlling the end point of coordinate travel does not have any reduction in the moving process, as for the speed and path between the relevant two points depends on the productivity.

In order to locate accurately on the basis of as high productivity as possible, the movement between the two related points is first to move quickly to the new position, and then slow down the 1-3 stage, let it slowly locate the point, so as to ensure its positioning accuracy.

(2) Point line control CNC lathe processing robot. This kind of NC lathe robot processing, not only to control the position between the two related points, but also to control the movement speed and route between the two related points.

Its route usually consists of straight lines parallel to each axis. The difference between the control and the point of NC lathe robot is that when the moving parts of the machine tool move, it can be processed along an axis direction (generally it can be cut at 45 ° oblique line, but not any slope linear cutting). The auxiliary function is the position control of the NC lathe robot, such as improving the spindle speed control, feed processing cycle, tool selection, and other functions.

(3) Contour control CNC lathe processing robot. The control device of this kind of CNC lathe can control two or more coordinate axes continuously at the same time.

In the process of machining, we should not only control the starting point and the end point, but also control the speed and position of each point in the whole processing process, so that the CNC lathe robot can process complex shaped parts according to the drawing requirements. Its auxiliary functions are also relatively complete.

CNC machining is classified according to CNC device

(1) Hard wire CNC lathe robot processing (commonly known as ordinary CNC, namely NC). The input, interpolation and control functions of the system are realized by integrated circuits or discrete components.

Generally speaking, the CNC system is not flexible, so it is composed of different hardware functions. This system was widely used before the 1970s.

(2) Flexible wire CNC lathe robot processing (also known as computer numerical control or computer numerical control, namely CNC or MNC). This system uses medium, large-scale and super large-scale integrated circuits to form numerical control equipment, or uses microcomputer and special integrated chips. Its main numerical control functions are almost completely realized by software. For different CNC lathe robots, it only needs to compile different software implementation, and hardware is almost universal.

So it has flexibility and adaptability, and it is easy to produce in batch. The quality and reliability of the system are improved by modularization of software and hardware. Therefore, the modern CNC lathe robot all uses the numerical control device.

CNC machining is classified according to the process use

(1) General CNC lathe robot processing. Compared with the traditional lathe processing, this kind of NC lathe robot processing has CNC turning, milling, boring, drilling, grinder and other mechanical processing methods. The possibility of this kind of CNC lathe robot processing technology is similar to that of ordinary machine tools, but it can process complex parts.

(2) CNC lathe robot processing. This kind of NC lathe robot processing is developed on the basis of ordinary NC lathe robot processing.

In the general CNC lathe robot is equipped with a tool library (can accommodate 10-100), the equipment composed of cutting tools and automatic tool equipment uses automatic tools to change the CNC lathe robot (also known as multi-step or boring and milling machining center, CNC lathe robot is usually called machining center), and the development direction of NC lathe robot processing is further automation and efficiency.

(3) Multi coordinate CNC lathe robot processing. Some complex shape parts can not be processed by three-dimensional CNC lathe, such as propeller, aircraft surface parts processing, need more than three-dimensional comprehensive movement to process the required shape.

Then the multi coordinate CNC lathe robot is used to process the robot. Its characteristics are that the number of control axes of CNC equipment is more, and the structure of lathe is also more complex. The number of coordinate axes usually depends on the processing technology requirements of the parts to be processed.