chengcg – Page 40 – CNC Machining & Turning, Milling, Metal parts

Basic introduction of drilling and tapping machine

Drilling and tapping center is a kind of metal cutting equipment. Its style and function are basically similar to machining center, but it is smaller than machining center. Generally, the stroke is no more than (x / y) 800 × 400mm. It is mainly used for drilling and tapping of nonferrous metals, 3C industry, aluminum substrate, etc. Although it can realize boring and milling, due to the low power of main motor, it can’t carry out heavy tapping of ferrous metals Cutting, but the efficiency and quality of drilling and tapping speed is more than 10 times of that of ordinary machining center. For 3C, communication industry and other industrial customers, it is the most ideal processing equipment.

Current overall market analysis:

Due to the rise of mobile phone industry, communication industry and tablet computer industry in recent years and the continuous upgrading to please consumers, the accompanying supporting processing industry is also rising, especially the demand for drilling machine is growing.

In the early stage of drilling and tapping center, the water-based cutting fluid (water-based) was used in the separate cooling water tank, and both stations were used. However, after a period of time, it was found that the water-based cutting fluid of drilling and tapping center was not good for drilling and tapping threads, especially for taps, which were “astringent” during machining and were very easy to break, and the quality of the tapped holes was not good. Therefore, we changed the drilling center to dry machining. When we arrived at the tapping station, kerosene was used for lubrication (kerosene was supplied by the pump alone, and the electrical control) to produce good thread quality, and the tap was rarely broken. The processing form of drilling and tapping Center: manually push the material to the conveying position, press the “swing up” button to enter the automatic cycle, and the two headstocks act at the same time. After the second feeding, the two headstocks return to the original position.

CNC machine tool is a widely used drilling and tapping center. CNC machine tool is a kind of advanced equipment with excellent performance, wide range of technology, high precision of drilling and tapping center and high production efficiency. One time clamping can complete drilling, reaming, boring, grooving and plane milling. In addition, it can also process holes with high precision. CNC machining is used for heavy machinery, engineering machinery, rolling stock, mining equipment, large motor and water turbine , steam turbine, shipbuilding, steel, military and other industrial sectors essential processing equipment. The CNC machine tool has the characteristics of good rigidity, high precision, strong reliability, convenient operation, beautiful appearance, etc., especially in the end face of square ram, it can also install various accessories or cooperate with the rotary table, which can further expand the application scope of CNC machine tool. CNC machine tools are mainly used for boring large and medium-sized parts of the hole, but also can complete drilling, expanding, reaming, milling plane and other work. The CNC machine tool is equipped with a change gear device, which can process metric or English internal thread. The end face can be turned by using the flat disc radial tool rest, which can be used online with the rotary table, and the inner hole and outer circle with large diameter and short length can be processed.

Installation process of CNC machining

The automatic tool changing device of machining center is composed of tool magazine and tool changing mechanism. There are many kinds of tool magazine, including disc type and chain type. The storage capacity of chain magazine is large.

In order to further shorten the non cutting time, some machining centers are equipped with two pallets which automatically exchange workpieces. One is loaded with workpieces for processing on the worktable, and the other is loaded and unloaded outside the worktable.

The tool change mechanism exchanges tools between the machine tool spindle and the tool magazine, commonly known as the manipulator; there are also no manipulator and the spindle directly exchanges tools with the tool magazine, known as the armless tool change device.

Machining center is divided into vertical type and horizontal type according to the arrangement of spindle. Horizontal machining center generally has indexing turntable or numerical control turntable, which can process all sides of the workpiece; it can also make joint movement of multiple coordinates to process complex space surface. The vertical machining center generally does not have a turntable, only for the top surface processing.

In addition, the machining center and spindle can be adjusted into horizontal axis or vertical axis of the vertical and horizontal adjustable machining center, they can process five surfaces of the workpiece.

The common lathe has a wide range of processing objects, a wide range of spindle speed and feed adjustment, and can process the internal and external surfaces, end faces and internal and external threads of the workpiece. This kind of lathe is mainly operated by manual workers with low production efficiency. It is suitable for single piece, small batch production and repair workshop.

Turret lathe and turret lathe are equipped with turret turret or return wheel turret which can hold multiple cutters. Workers can use different cutters to complete a variety of processes in one clamping process, which is suitable for batch production.

The automatic lathe can automatically complete the multi process processing of small and medium-sized workpieces according to a certain program. It can automatically load and unload materials and repeatedly process a batch of the same workpieces. It is suitable for mass production.

Multi Tool semi-automatic lathe can be divided into single axis, multi axis, horizontal and vertical. The layout of the single axis horizontal lathe is similar to that of the ordinary CNC lathe, but the two groups of tool holders are respectively installed in the front and back or up and down of the spindle, which are used to process disc, ring and shaft workpieces, and their productivity is 3-5 times higher than that of the ordinary CNC lathe.

The lathe can imitate the shape and size of the template or sample, and automatically complete the processing cycle of the workpiece. It is suitable for small batch and batch production of the workpiece with complex shape. The productivity is 10-15 times higher than that of the ordinary lathe. There are multi turret, multi axis, chuck type, vertical and other types.

The spindle of the lathe is perpendicular to the horizontal plane, the workpiece is clamped on the horizontal rotary table, and the tool rest moves on the beam or column. It is suitable for machining larger, heavier workpieces which are difficult to install on ordinary lathe. It is generally divided into single column and double column.

When lathe is turning, the tool rest makes radial reciprocating motion periodically, which is used for forming tooth surface of forklift milling cutter, hob, etc. Usually with grinding accessories, a small grinding wheel driven by a separate motor is used to grind the tooth surface.

Lathe is used to process a certain kind of workpiece specific surface lathe, such as crankshaft lathe, camshaft lathe, wheel lathe, axle lathe, roll lathe and ingot lathe.

The lathe is mainly used for turning, but after adding some special parts and accessories, it can also carry out boring, milling, drilling, inserting, grinding and other processing, with the characteristics of “one machine with multiple functions”, which is suitable for the repair work of engineering vehicles, ships or mobile repair stations.

Processing has the following advantages:

① The number of tooling is greatly reduced, and complex tooling is not needed to process complex parts. If we want to change the shape and size of the parts, we only need to modify the processing program of the parts, which is suitable for the development and modification of new products.

② The machining quality is stable, the machining accuracy is high, and the repetition accuracy is high, which can meet the machining requirements of aircraft.

③ In the case of multi variety and small batch production, the production efficiency is high, which can reduce the time of production preparation, machine adjustment and process inspection, and reduce the cutting time due to the use of the best cutting quantity.

④ It can process complex surface which is difficult to be processed by conventional methods, and even some parts which cannot be observed.

The working principle of CNC machining is divided into several points

Firstly, in the process of clamping, in order to simplify the machining origin of each positioning surface relative to the work center, there should be accurate coordinate dimensions. Secondly, the orientation of mechanical parts installation is consistent with the orientation of workpiece coordinate system and machine coordinate system selected in programming, and directional installation. In the production and processing of batch precision mechanical parts, it should be considered that the fixture suitable for new workpiece can be changed after a short time of disassembly. As the auxiliary time of machining center has been compressed very short, the loading and unloading of supporting fixture can not take up too much time.

In the production of the fixture, should have as few workpieces and higher stiffness. The fixture should be open as far as possible, the space position of clamping workpiece can be low as possible, and the installation fixture should not interfere with the tool path. In order to avoid affecting the processing process, ensure that the processing content of the workpiece is completed within the stroke range of the spindle!

When there is an interactive worktable, the fixture design must prevent the space interference between the fixture and the machine tool due to the movement, up support, down support and rotation of the worktable. Try to complete all the processing contents in one clamping. When it is not necessary to replace the clamping point, special attention should be paid not to damage the positioning accuracy due to replacing the clamping point. If necessary, it should be explained in the drawing processing technology.

How to achieve control balance in CNC machining

CNC (numerical control machine tool) is the abbreviation of computer numerical control machine tool, which is a kind of automatic machine tool controlled by program. The control system can logically process the programs with control codes or other symbolic instructions, and decode them by computer. Thus, the machine tool can perform the specified action, and the blank can be processed into semi-finished parts by cutting tools.

The computer gong machining center is a highly mechatronic product. After the workpiece is clamped, the CNC system can control the machine tool to automatically select, change the tool, set the tool, change the spindle speed and feed rate according to different processes. It can continuously complete drilling, boring, milling, reaming, tapping and other processes, thus greatly reducing the workpiece clamping time, measuring and machine tool adjustment and other auxiliary processes It has good economic effect for the parts with complex machining shape, high precision and frequent variety replacement.

CNC milling machine is developed on the basis of general milling machine. The processing technology and structure of the two machines are basically the same. However, CNC milling machine is an automatic processing machine controlled by program, so its structure is very different from that of ordinary milling machine. Considering the limitation of traditional reliability method, the superiority evaluation principle of extension engineering method is applied, This paper defines and calculates the influence degree and influence factor of each subsystem and its failure mode of machining center on the reliability of machining center. Combined with the failure example of a machining center, the detailed calculation is carried out under the condition of comprehensively considering all failure factors, and the reliability improvement measures are put forward.

It is correct that not all tools need to be balanced, especially when the process results in increased costs and additional steps. Whether to balance the cutting tools depends on the specific situation. At high speed, the balance effect is the most prominent, but at any speed, the balance tool produces better shape and position accuracy, improves surface finish and prolongs tool life.

How to improve wear resistance in parts processing

Avoid sliding friction pairs made of the same materials

Avoid too large thickness of white alloy

Avoid increasing the requirements for the whole part in order to improve the wear resistance of the part surface
Avoid local wear of large parts and scrap the whole parts
When white alloy is used as bearing liner, attention should be paid to the selection of bearing material and the design of bearing structure
The lubricant supply is sufficient, covering the working face
The lubricating oil tank should not be too small
Do not let the filter filter out the additive in the lubricant
The size, position and shape of oil groove of sliding bearing shall be reasonable
The amount of grease added into the rolling bearing should not be too much
Add a certain amount of wear allowance to the easily worn surface of parts
Pay attention to the adjustment of worn parts
The velocity and pressure difference between different points on the same contact surface should be small
Adopt dust-proof device to prevent abrasive wear
Avoid step wear
Contact oil seal cannot be used for sliding bearing
The easily worn parts shall be protected
For easily worn parts, the structure of automatic wear compensation can be adopted
Avoid the distance between the force point and the support point
Avoid cantilever structure or reduce cantilever length
Don’t ignore the beneficial effect of working load
Avoid using friction to transfer force for parts under vibration load
Avoid the unbalanced force in the mechanism
Avoid considering only one way of force transmission
High speed computer gong processing should not ignore the influence of part deformation on stress distribution during working
Avoid large tensile stress on iron castings
Avoid bending stress on thin rod
Avoid excessive rigidity of parts under impact load
Avoid rough surface or scratch of parts under variable stress
Residual tensile stress should be avoided on the surface of parts under variable stress
The stress concentration of parts under variable load should be avoided or reduced
Avoid that the local structures that affect the strength are too close to each other
Avoid pre deformation in machining of mechanical parts, and the deformation direction is the same as that produced by working load
The diameter of pulley and drum of wire rope shall not be too small
Avoid too many times of wire rope bending, and pay special attention to avoid repeated bending during machining of mechanical parts
Allowance shall be left at the joint of wire rope and drum during lifting
The intermediate parts of CNC machining center that can not transfer force should be avoided as far as possible
Try to avoid additional force caused by misalignment of axis during installation
Minimize the force acting on the foundation.

The reason why the machining center does not grasp the tool

There are two ways of tool change in vertical machining center: manipulator tool change and direct tool change. There are many reasons why the tool magazine can not grasp or change the tool correctly. To sum up, there are the following 7 points.

It is caused by solenoid valve or magnetic induction switch of tool magazine

Vmc750 vertical machining center adopts direct tool change mode, and the tool magazine has two actions: swing and rotation. A three position five way solenoid valve is used to control the cylinder to drive the tool magazine to swing, and a single-phase tool magazine motor is used to realize the rotation of the tool magazine. There is a progressive switch in the magazine for counting. When changing the tool, the tool magazine should be placed at the spindle position first, put the original tool back into the tool sleeve, and then rotate the tool magazine to find the next tool. The spindle position and original position of Dongguan high-speed computer gong machining tool magazine are determined by two magnetic switches on the cylinder of the tool magazine. When the solenoid valve and magnetic switch fail and give an alarm [39-12], the tool magazine does not move to the spindle position within the specified time; when [39-15], the tool magazine does not move to the original position within the specified time. At this time, check whether the solenoid valve has action. If the swing magazine can’t hear the action sound of the solenoid valve all the time, check the valve manually (at this time, it’s better to disconnect the output end of the valve). If it’s broken, replace it.

The three switch values in the headstock are incorrect

Whether the state of the spindle after grasping the tool is correct or not is judged by the three progressive switches (sq7 clamping switch, SQ8 release switch, sq9 no tool switch) in the spindle box. The three switches are distributed in a triangle and sense different parts of the loose broach cylinder. The correct position switch value should be (1) normal no knife: sq9 and sq7 lights on; (2) normal knife: only sq7 lights on; (3) press the knife release key: only SQ8 lights on. Usually, the three switch states are not correct. The alarm code is [39-4]: rod failure; [39-13]: rod loosening failure; [39-14]: rod clamping failure; [39-34]: tool not clamped. These kinds of alarms are related to the three progressive switches. It is necessary to check whether the switches are good or bad and adjust them to the appropriate position to make the switch indication correct.

Damage of light board

If the valve is correct, it is necessary to check the status of I / O switch value: whether the signal of spindle position slidrum spdl000:00 / 15 or original position slidrum park000:00 / 16 has been given. Check whether the corresponding 24 V level signal on the light disaster board, the fuse on the board and the 110 V voltage signal from the light disaster board are sent to the solenoid valve, and check the signal voltage all the way to find out the fault point. Vertical CNC machine tools are usually more likely to damage the safety tube and light tube. Just buy the same glass safety tube or light tube and replace it.

Mechanical jamming

If the handle of the knife is stuck, you can hear the pressing sound of the cylinder by pressing the release key, but the knife just can’t come off. This is due to the tool handle not pay attention to maintenance and rust, or due to the spindle taper hole or tool handle with iron chips caused by stuck. At this time, just press and hold the release key. Under the condition of confirming that the cylinder of the release broach is pressed down, use wood to act on the edge of the handle and knock the tool off gently. Another problem is that the pull rod is stuck. It is necessary to remove the spindle and knock out the pull rod. At this time, there are usually scratches on the surface of the pull rod. If it is serious, you need to mill off the scratches and knock them in again.

Sometimes the cutterhead is mechanically jammed. In addition to mechanically cleaning the iron filings stuck in the cutterhead, the operator is required to remove the iron filings in the cutterhead in time to keep the cutterhead and the handle clean.

It is caused by incorrect counting switch of tool magazine

Incorrect counting switch of tool magazine can also lead to incorrect tool change or grabbing. There are [39-38] alarms: the tool sleeve does not turn to the correct position; [39-44] the tool magazine cannot be placed to the spindle position. Check whether the switch is damaged and adjust the switch state to the correct sensing position.

CNC system failure

During the maintenance, some strange phenomena have been encountered, such as normal start-up of the equipment, self inspection, loading system, secondary power on, calibration of the mechanical zero point, and then calibration of the tool magazine, the tool magazine can neither rotate nor swing. After checking the I / O switch value, it is found that the switch value pridrum Park and pridrum SPDL are both 0 when pressing the fl key (Park home position) and the F2 key (SPDL spindle position), indicating that the signal is not given and the magazine will not move naturally. Check the self-test table, computer gong processing, mechanical parts processing, CNC machine tool processing, Dongguan high-speed computer gong processing found that the left main board, right main board, bridge board, servo board, I / O board, touch screen and keyboard board passed normally. However, when the electrical cabinet was opened for inspection, it was found that the bridge board indicator of CNC system was incorrect. Through the exchange and comparison test of two machine tools, the fault point is finally locked on the bridge plate and recovered after replacement.

Machine tool protection

Sometimes, due to misoperation, the protection action of the machine tool makes it impossible to grasp the knife correctly. At this time, just press the emergency stop switch to power on again, or directly shut down the machine and restart it.

Computer gong processing – high strength steel

When the material is formed by stamping, it hardens. The hardening degree of different steels is different. Generally, the increase of 3 Ksi of high strength low alloy steel is less than 10%. Note: the yield strength of dual phase steel increases by more than 40% by 20ksi! During the forming process, the metal will become completely different, completely unlike before the stamping process begins. The yield strength of these steels increases a lot after being stressed. The higher yield stress and work hardening of the materials processed by CNC lathe are equal to the great increase of flow stress. —-This results in the need for more tonnage to make parts – it increases the deformation temperature of the metal (which may burn or destroy improper lubricants), hard spots increase die wear – and the coating may not help or last as long as expected.

In the past, in the production of deep drawing or re punching parts, everyone thought that pressure resistant (EP) lubricating oil was the best choice to protect the mold. Sulfur and chlorine EP additives have been mixed into pure oil to improve mold life for a long time. However, with the emergence of new metal high strength steel and strict environmental protection requirements, the value of EP oil-based lubricating oil has decreased or even lost its market.

The development trend of modern CNC lathe precision machining is high speed, high precision, high reliability, multi-function, compound, intelligent and open structure. The main development trend is to research and develop intelligent full-function universal CNC device with open structure in both software and hardware. CNC technology is the foundation of machining automation and the core technology of CNC machine tools. Its level is related to the national strategic position and the level of national comprehensive strength. It develops with the development of information technology, microelectronics technology, automation technology and detection technology. CNC lathe precision machining is a kind of CNC machine tool with tool library and automatic tool change, which can carry out a variety of processing operations on the workpiece in a certain range.

CNC lathe precision machining is the use of CNC technology to control machining machine tools, or equipped with CNC system. The use of CNC machine tools to process mechanical parts, known as CNC machining. NC machining is different from ordinary machine tools. CNC machining needs control information, such as tool feeding, the sequence of various actions, and various auxiliary functions (such as soil shaft speed, speed, tool change, coolant switch, etc.), etc. the program is stored in the control in digital form, and the automatic machining machine tool is realized through digital control device.

CNC lathe precision machining is an efficient automation tool, is a typical electromechanical products, it can achieve high-speed processing, high precision, high degree of automation. Mechanical parts processing is an important difference from other types of automatic machine tools: CNC machine tools use flexible automation technology, that is, when the processing object changes, in addition to clamping parts and replacement tools, only need to change the processing program can automatically find out new parts, without changing other hardware equipment.

The precision of computer gong forming

How to control the accuracy of mechanical parts in the process of aluminum oxidation treatment? If there is a precision request for the thickness process dimension of fine mechanical parts, the process size or negative difference dimension of the machined parts can be increased according to the accurate size after oxidation treatment, so as to ensure that the fine and dense machined parts meet the process requirements on the drawing after the oxygenation treatment. In the machining process of mechanical parts, not only the paper size thickness has precision, but also the size request of fine hole, step, hole to edge, etc., which is the same as the processing method of thickness request.

Aluminum oxidation has an impact on the accuracy of mechanical parts, but it can be controlled in the machining process of mechanical parts, which can ensure and meet the process requirements on customer drawings!

The content of mold precision includes four aspects: dimensional accuracy, shape accuracy, position accuracy and appearance accuracy. Because of the working time of the mold, the upper and lower die position accuracy is the most important among the four kinds of precision.

Mold precision is to serve the accuracy of products, high-precision products must be guaranteed by higher precision molds, mold accuracy generally must be higher than the product accuracy of 2 or more levels.

Methods of improving die precision

1。 The precision guarantee of mould processing equipment

2。 Precision requirements of parts in mould manufacturing

①。 Die material accuracy requirements

The processing tolerance of die steel should be controlled within 300×300 + 0.005-0 ± 0.005300×500 + 0.01-0 ± 0.01500×800 + 0.01-0.01 ± 0.015800×1200 + 0.02-0.02 ± 0.02. Precision requirements of mould parts

a。 The precision of Sumi series is within 0020.002mm, and the precision of guide sleeve can be controlled.

b。 The edge forming punch is made of Misumi standard material: SKD-11, hardness: 60-62hrc, and the edge shape is: dregth, which is usually used to form the inner hole or cylinder shape of products. The precision of punching needle can be controlled within ± 0.01mm, and it can be about 2um for special requirements, and keep mirror like.

3。 The size of die gap is the main basis of die design and manufacturing accuracy. In order to ensure the accuracy of product size and shape position, as well as the product quality (such as the cross-section quality and burr height), the gap between the concave and convex dies must be ensured.

4。 The requirements of die construction precision are as follows. Luo Baihui said that from the perspective of processing and assembly, the accuracy of mold base mainly includes the following aspects:

a。 The size and position of the upper and lower plane of the template are consistent;

b。 Flatness and parallelism of large plane of formwork;

c。 Perpendicularity of guide hole to large plane;

d。 Perpendicularity between adjacent sides of formwork;

e。 The fitting accuracy between guide pillar and guide sleeve.

The main methods to ensure the accuracy of mold base are as follows:

a。 The one-time processing method is that after the large plane processing of the template is completed, the upper and lower templates are clamped together, and the plane dimensions and guide holes of two templates are processed at one time.

b。 One of the four guide holes is deviated from the symmetrical position to ensure the assembly orientation of the die.

c。 Datum is used to calibrate the table.

d。 Guide pillar and guide sleeve with high matching precision are adopted.

e。 Improve the machining accuracy of parts.

②。 From the perspective of machining and assembly, the accuracy of punch mainly includes:

a。 The shape and size accuracy of punch;

b。 Perpendicularity between adjacent sides of punch.

③。 From the perspective of processing and assembly, the accuracy of female die mainly includes:

a。 The accuracy of shape and dimension of female die;

b。 Perpendicularity between adjacent sides of die;

c。 Perpendicularity of die side to large plane;

d。 Position degree of die.

5。 The precision of forming process ensures that in the process of forming structure, the coordinate processing method is adopted whether it is processed by computer gong, EDM, WEDM or ordinary milling machine. The guarantee of the accuracy mainly depends on the accuracy of the machine tool and the accuracy of the operator’s calibration table and score. It is considered that the concept of die precision should also run through the whole process of mold design and manufacturing, just as the guiding principle and guiding ideology of establishing enterprise product quality assurance and management system.

Processing range of different types of CNC lathes

High speed, precision, turning center and four axis linkage CNC lathe.
High speed, high precision CNC milling and boring machine and high-speed, high-precision vertical and horizontal CNC machining center. It mainly meets the processing requirements of large and complex structure supports, shells, boxes, light metal material parts and precision parts in automobile engine cylinder block and cylinder head, aerospace, high-tech industries and other industries.
Heavy and Super Heavy CNC machine tools: CNC Floor milling and boring machine, Heavy CNC gantry boring and milling machine and CNC gantry machining center, Heavy CNC horizontal lathe and vertical lathe, CNC heavy hobbing machine, etc. these products meet the requirements of parts processing in energy, aerospace, military, ship main engine manufacturing, heavy machinery manufacturing, large mold processing, steam turbine cylinder block and other industries.
CNC grinding machines: CNC ultra precision grinder, high-speed and high-precision crankshaft grinder and camshaft grinder, all kinds of high-precision high-speed special grinding machines, etc., to meet the requirements of precision and ultra-precision machining.
CNC EDM machine tools: large precision CNC EDM forming machines, CNC low-speed WEDM machines, precision small hole EDM machines, etc., mainly meet the special needs of large and precision mold processing, CNC machining precision parts processing, taper hole or special-shaped hole processing, aerospace, aviation and other industries.
CNC metal forming machine tools (forging equipment): CNC high-speed precision sheet metal stamping equipment, laser cutting compound machine, numerical control powerful spinning machine, etc., mainly meet the needs of sheet metal mass production in automobile, motorcycle, electronic information industry, household appliances and other industries, as well as the processing requirements of various thin-walled, high-strength and high-precision rotary parts in automobile hub and military industry.
CNC special machine tools and production lines: FMS / FMC and various special CNC machine tools. This kind of production line is aimed at the processing requirements of cylinder block, cylinder head, gearbox case and other parts of various varieties and variable batches in automobile, household appliances and other industries.

Economic CNC lathes have different processing methods. When the program of economical CNC lathe is finished, the tool can’t return to zero. Generally, this phenomenon is caused by control system failure. When the cutting tool is feeding or processing, it is required to run at a low speed. At this time, the stepper motor runs at a low speed and uses low-voltage power supply. When the program returns to zero, it requires fast return. At this time, the stepping motor is required to run at high speed, and the high-voltage drive power supply is used to increase the output torque and ensure normal return to zero. A switch triode is used to control the output of the high-voltage drive power supply. When the switch triode is damaged and returns to zero at high speed, the high-voltage power supply cannot be opened, and the output torque of the stepping motor is not enough, resulting in the return to zero and step loss, resulting in the cutter can not return to the original point. In view of this fault, the switch triode can be replaced.

Economical CNC lathe is an automatic machine tool with high precision and high efficiency. Equipped with multi station turret or power turret, it has a wide range of processing performance, and can process complex workpieces such as linear cylinder, oblique cylinder, circular arc and various threads, grooves, worms, etc. It is widely used in the processing and manufacturing of electrical appliances, instrumentation industry, automobile, motorcycle accessories, fasteners, bearings, photographic equipment, film machinery, hardware tools, clocks, eyes, cultural and educational supplies, motors, valves, gas pipe fittings and other high-precision and complex parts. It is the most ideal high-efficiency equipment in the hardware machinery processing industry.

Economical CNC lathe is developed on the basis of common lathe, but its automation degree has been greatly improved. The automatic control system of economical CNC lathe is mainly composed of single chip microcomputer. Through the control program, the longitudinal and transverse feed device and tool changing device of the machine tool are controlled, and the parts are processed automatically.

When the program of economical CNC lathe is finished, the tool can’t return to zero. Generally, this phenomenon is caused by control system failure. When the cutting tool is feeding or processing, it is required to run at a low speed. At this time, the stepper motor runs at a low speed and uses low-voltage power supply. When the program returns to zero, it requires fast return. At this time, the stepping motor is required to run at high speed, and the high-voltage drive power supply is used to increase the output torque and ensure normal return to zero. When the switch triode is damaged and returns to zero at high speed, the high-voltage power supply cannot be turned on, and the output torque of the stepping motor is not enough, resulting in the return to zero and loss of step, so that the cutter can not return to the original point. In view of this fault, the switch triode can be replaced.

Decomposition of CNC machining process

CNC machining center is an efficient automatic machine tool suitable for machining complex parts by mechanical equipment and CNC system. Its comprehensive processing capacity is stronger, and it can finish the processing after clamping the workpiece. The efficiency of the batch workpiece with high processing accuracy and medium difficulty is 5 ~ 10 times higher than that of the ordinary equipment. In particular, it can complete the processing that many ordinary equipment can not complete, and the complex shape, high-precision single processing or small batch and multi variety production are more suitable.

Here are some tips to teach you how to operate the CNC machining center easily

1。 In order to simplify the positioning and installation, the machining center of each fixture positioning surface should have accurate coordinate size.

2。 In order to ensure the part installation position and programming direction consistency of workpiece coordinate and machine coordinate system, and installation direction.

3。 Can be deleted after a short period of time to adapt to the new workpiece fixture. Because the auxiliary time of CNC machining center is compressed very short, it can not take too much time to support fixed loading and unloading.

4。 Fixtures should have as few elements and high stiffness as possible.

5。 Try to open the fixture. The space position of clamping elements can be very low, and the installation fixture and tools can not interfere in one step.

6。 Ensure that the parts within the range of spindle travel are processed.

7。 Due to the movement of worktable and rotation movement, fixture design must prevent the space interference of fixture and machine tool.

8。 Try to finish everything in the clamping process. When replacing the clamping point, pay special attention not to damage the positioning accuracy of the replacement clamping point, if necessary, during this process.

9。 The flatness of fixture base, worktable and fixture bottom must be within 0.01-0.02 mm, and the surface roughness should not be greater than ra3.2. CNC CNC lathe is a kind of high-precision and high-efficiency automatic machine tool. The use of CNC lathe can improve the processing efficiency, To create more value, the appearance enterprises of CNC lathe get rid of backward processing technology. The processing process of CNC lathe is similar to that of ordinary lathe. However, due to the clamping and automatic processing of CNC lathe, the following aspects should be paid attention to.

Reasonable selection of cutting parameters

For effective metal cutting, machining materials, cutting tools and cutting conditions are the three main factors. These determine the processing time, tool life and machining quality. Cutting conditions must be selected reasonably for economical and efficient processing methods.

The three elements of cutting conditions: cutting speed, feed and cutting depth directly cause damage. With the increase of cutting speed, the point temperature will rise, resulting in mechanical, chemical and thermal wear. 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 behind, cutting temperature rise, wear. It is less than the effect of cutting speed. Cutting depth has no effect on cutting speed and feed, small cutting depth, but cutting material in hardened layer will also affect tool life.

According to the user’s processing material, hardness, cutting conditions, material selection, feed and cutting depth, the cutting speed is used.

Based on the selection of the most suitable process conditions, these factors are selected. Regular life and stable wear are the most ideal conditions.

However, in practice, the selection of tool life and tool wear, through machining size, surface quality, noise reduction, heat and so on. Under certain treatment conditions, it is necessary to study according to the actual situation. Difficult to machine materials such as stainless steel, heat-resistant alloy, can use coolant or choose a good rigid blade.

Reasonable selection of cutting tools

1。 Rough rotation, should choose high strength, good durability knife, in order to meet the large car turning, feedback.

2。 The essence of automobile is to select high precision, durable and good cutting tools to ensure the machining accuracy.

3。 Reduce the conversion time and knife convenience, should try to use machine knife and machine clip blade.

Select fixture

4。 General fixture should be selected to clamp workpiece as much as possible, and special fixture should be avoided;

5。 The coincidence of parts positioning datum reduces the positioning error.

Determine the processing route

Machining path is the part of tool path and direction relative to each other in the process of exponential control.

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

2。 Shorten the processing route as far as possible and reduce the idle travel time of the tool.

Computer gong processing – product processing center

Product processing center refers to the processing center used to process products. There are large products and small products here. However, large machine tools are usually used to process molds, and there are a small number of products. Product processing center is the most widely used in the field of CNC machining center, because there are more products than molds. The products of many industries need to be processed by vertical machining center.

The main functions of the equipment are as follows:

Milling, CNC milling machine generally should have three coordinate linkage function, which can carry out linear interpolation and arc interpolation, and automatically control the rotation of the milling cutter relative to the workpiece movement for milling.
Drilling, reaming, reaming, countersinking, boring, etc. can be carried out by using fixed size hole processing tools, or milling cutter can be used to mill holes of different sizes;
Tool compensation function, generally including tool radius compensation function and tool length compensation function.
For the conversion of metric and English units, metric units (mm) and English units (inch) can be selected for programming according to the marking of drawings, so as to adapt to the specific situation of different enterprises.
Absolute coordinate and incremental coordinate programming, the coordinate data in the program can be absolute coordinates or incremental coordinates, so that the data can be calculated or between 20%. The programming is more convenient.
Adjustment of feed speed and spindle speed. The control panel of CNC milling machine is generally equipped with multiple switch of feed speed and spindle speed, which is used to adjust the actual feed speed and actual spindle speed at any time according to the processing status and program setting value during program execution, so as to achieve the best cutting effect. Generally, the feed speed adjustment range is between 0% ~ 150%, and the spindle speed adjustment range is 50% ~ 1.

This machining center is the commonly used equipment in CNC industry. The CNC equipment is composed of mechanical equipment and CNC system. It is an efficient automatic CNC machine tool used to process complex shaped workpieces. This equipment is originally developed from the CNC milling machine, but also in the later application process in the technical aspects of change. Moreover, this equipment is also a highly mechatronic product. After the workpiece is clamped, the CNC system can control the machine tool to automatically select according to different working procedures. In addition, it can automatically change the cutting tool and automatically change the spindle speed and feed rate. In addition, the equipment can also continuously complete drilling and boring Milling, reaming, tapping and other processes, which can greatly reduce the clamping time of the workpiece, as well as the auxiliary process time such as measurement and machine tool adjustment, and the more complex processing shape and higher accuracy requirements in application, as well as good experience in parts with frequent variety change Moreover, the current application equipment can gradually become the most important equipment in the mechanical processing industry,

The supporting parts of machining center mainly refer to machine bed, upright, beam, base and other large parts. Its function is to support parts, bear force and ensure their mutual position. Although the shape, geometric size and material of the support are various, they all satisfy the following points.

The anti vibration property of the supporting part refers to its ability to resist forced vibration and self-excited vibration. Vibration will not only make the machine produce noise, but also affect the processing quality. Therefore, the support should have sufficient vibration resistance and have the required dynamic characteristics. The main factors affecting the vibration resistance of the support are: the stiffness of the support, the natural frequency of the support, the damping of the support, the support condition of the support and the material of the support, etc. in practice, the vibration resistance of the support is often improved by selecting the high damping material, adopting the high damping component, and improving the support condition of the support with the Linjia vibration damping pad.
Stiffness requirements the stiffness of the supporting part refers to the ability of the support to resist deformation under the action of constant load and alternating load. The former is called static stiffness and the latter is dynamic stiffness. The static stiffness depends on the structural stiffness and contact stiffness of the supporting timber body. The dynamic stiffness is not only related to the static stiffness, but also to the damping and natural frequency of the supporting system. The most important factors affecting the stiffness of the support are the material and structure of the support. The stiffness of the support can be improved by using high rigid materials and increasing the elastic modulus of the material; the contact stiffness can be effectively improved by increasing the surface contact area, increasing the preload and improving the surface quality; It is an effective measure to improve the stiffness of supporting parts by adopting reasonable cross-section shape and configuring the stiffeners and stiffeners.
The main factors affecting the thermal deformation of the supporting parts of machining center are: the structure of the support, the heating of the moving parts and the external heat source. The thermal deformation can be reduced by adopting the thermal symmetry structure, isolating the heat source, forced cooling and quick chip removal