CNC Technology – Page 33 – CNC Machining & Turning, Milling, Metal parts

Operation process of milling head in CNC machining

CNC milling head can increase the application range, if there is no milling head, boring machine can only process one station, and after installing the milling head, it can install more than 8 stations, and the extension range of spindle can also be expanded.

The use of milling head should also be based on the parameter characteristics of each model, in the appropriate processing conditions, that is to select milling head products for processing.
Avoid long time let milling head at the highest speed of continuous processing, this kind of shaft running mode is easy to cause overwork, will damage the service life of the machine.
It should be confirmed several minutes before commissioning. Each time processing, need to select the appropriate speed and feed processing. Pay attention to adjust the speed, feed and cutting depth gradually until the maximum machining efficiency is achieved.
In most cases, the milling head uses non-contact oil seal. If you want to use cooling water in the machining process, you should avoid adding it directly. Instead, you should run for a while before spraying water, and adjust the direction of the cooling water nozzle to spray water towards the tool, so as to prevent the cooling water from penetrating into the body and causing damage to the machine.

In the process of CNC machining center working, intermittent current alarm appears, English prompt appears on the display interface, 12 words appear in the spindle display module, and 0 display appears at the power module, which can be directly understood as zero voltage. From this point, it can be preliminarily inferred that there is current and leakage at the fault part of CNC machining center.

When checking other parts that may cause current alarm, there is no special phenomenon. The material of processing parts is in line with the operating conditions of CNC machining center, and there is no error in speed and processing mode, so there is no current overload phenomenon.

Check the circuit and find no abnormality,

CNC machining center is the use of three-phase power supply, the voltage is normal, so it is not circuit failure.

When observing the current alarm of CNC machining center again, it is found that the main position of the equipment is in the same feeding area every time the alarm is given. Further observation shows that the wire at the end of the threading slot is damaged, so when the spindle of CNC machining center moves to this area, the wire will cause short circuit fault.

After finding the cause of the fault, it is necessary to cut off all the power supply of CNC machining center, replace the damaged wire, and pass the new wire through the bend at the end of the slot.

The common sheet parts such as washer, friction plate, sample plate and thin plate, due to poor rigidity, heat dissipation difficulty, bending after heat treatment, clamping deformation during clamping and warping during grinding, usually use magnetic chuck to grind on the surface grinder. After grinding, the magnetic attraction is removed, and the sheet work is restored to its original state, so it is difficult to ensure the processing accuracy. If the following clamping methods are adopted to ensure the positioning and clamping of the sheet workpiece in the free state, and the double end face is used for grinding, good results can be achieved and the machining accuracy requirements of the parts can be met.

1 elastic gasket clamping mode, {i5 E3 U8 d * [9 F

When grinding the sheet workpiece on the surface grinder, the elastic clamping mechanism is adopted to realize the positioning and clamping of the sheet workpiece in the free state. A layer of rubber with thickness of 0.5mm is padded between the workpiece and the magnetic worktable. When the workpiece is affected by the magnetic attraction, the rubber is compressed and the elastic deformation becomes smaller, so that the flat plane of the workpiece can be ground. Repeated grinding for several times can meet the requirements of machining accuracy.

Using temporary measures to strengthen the rigidity of sheet workpiece: Z8 V2 I6 s * U2 E. I – [7 V

Epoxy resin is used to bond the sheet to a flat plate in free state. Place the plate and the sheet on the magnetic chuck. After grinding the plane of one end of the sheet, remove the sheet from the flat plate, put the flat side on the magnetic chuck, and then grind the plane of the other end of the sheet. Due to the fluidity of epoxy resin before hardening, it can fill the gap between the sheet workpiece and the flat plate. When the epoxy resin is hardened, the workpiece and the plate are bonded together to form a whole, thus greatly enhancing the rigidity of the workpiece. Under the magnetic force attraction, the sheet workpiece will not produce clamping deformation in CNC machining, which creates the conditions for grinding out the flat plane. Thick grease can also be used instead of epoxy resin to fill the gap between the sheet workpiece and the magnetic chuck, so as to enhance the rigidity of the workpiece, and good results can also be obtained.

Mechanical clamping mode ‘H9’) g% B x / J

Therefore, the small flat tongs of the worktable with magnetic force can absorb the workpieces. The feed rate is gradually reduced to grind one plane of the sheet workpiece and then take it off. At this time, the ground plane is put on the magnetic worktable, and then the other plane of the sheet workpiece is grinded again and again, and the flatness of the two planes meets the requirements. (Y4 @ 7 F. Z0 F “S9 X4 vacuum clamping mode ‘d0 L1 Q0 | 3 {8 h” g (V / K: l)

The pressure of atmosphere is used to clamp the workpiece for grinding.

Its working principle is: the clamp is provided with a rubber sealing ring, and the sheet workpiece is placed on the rubber sealing ring, so as to form a sealing cavity between the workpiece and the clamp. The vacuum pump is used to draw the indoor air from the air extraction hole, and the workpiece is clamped. Because of the small clamping force, the circular grinding method can be used for grinding. When one end of the workpiece is ground and the other end of the workpiece is ground, the above method can be used and satisfactory results can also be obtained.

How to deal with oil leakage of CNC machine tools

Design reasons

One of the main reasons for machine tool leakage is due to unreasonable design. Due to the neglect of the particularity of sealing technology, the design of sealing structure is unreasonable, resulting in the leakage of machine tool. Its performance is that the design scheme of the sealing structure is not suitable for the working pressure, working temperature, medium characteristics and environmental conditions; ventilation, oil return, liquid guide device and other measures are not considered in the design, such as the place where the oil return labyrinth groove should be set is not set; computer Gong processing | mechanical parts processing | Dongguan CNC machining center | Dongguan high-speed computer gong processing bearing seat is lubricated with thin oil and the limit value is high The rotation speed is very high, the oil temperature is very high, but there is no vent. Wechat for metal processing, with good content, is worthy of attention. In the design of sealing structure, we did not pay attention to anti-corrosion, anti vibration, pressure equalizing and dredging measures, but only one-sided considered plugging; the screw holes on the box were designed as through holes without sealing measures; the box cover did not take corresponding sealing gasket; the matching relationship between the shaft and the box hole was unreasonable, the gap was too large; the interference between the sealing ring and the shaft did not meet the standard requirements; the design of the sealing groove was not up to standard All these will cause oil leakage.

Manufacturing reasons

This is one of the important reasons for the leakage. The main problems are machining accuracy and surface roughness. For example, only turning is used in the place where grinding treatment is needed, resulting in the surface roughness of the processing place not meeting the requirements, resulting in leakage; for various pumps and valves in the hydraulic system, the leakage is controlled by clearance. If the manufacturing accuracy is out of tolerance and does not meet the design requirements, the internal leakage will be increased and the work efficiency will be reduced; the leakage often occurs in castings If preventive measures are not taken, these defects are often the source of oil leakage in the process of equipment use.

Reasons for equipment installation

The quality of equipment installation also has a greater impact on leakage. In practical work, equipment installation personnel do not assemble according to the correct assembly process, computer gong processing, mechanical parts processing, Dongguan CNC machining center, Dongguan high-speed computer gong processing or equipment installation personnel do not install correctly, assembly errors, or assembly process confusion, etc. are easy to cause equipment investment Leakage occurs after use. Moreover, when the equipment installation personnel carry out the assembly operation, if they use the big hammer and other tools to operate the place that should be knocked lightly, it will cause oil leakage due to the damage of individual parts of the equipment. Wechat for metal processing, with good content, is worthy of attention. Because the installation personnel do not pay attention to the working principle of the equipment or ignore the technical requirements of the drawings, the reverse installation of the framework oil seal and other seals will inevitably lead to leakage.

Reasons for sealing elements and materials

Improper selection of sealing elements and materials will shorten the service life of the sealing device, lead to poor sealing performance and easily lead to equipment leakage. For example, the use of hardness and working pressure does not adapt to the sealing rubber, or the selection of internal and external diameter is not suitable for the sealing ring. In addition, the oil resistant rubber products used for oil pipes and pipe joints will be aged, hardened and brittle due to long-term use, resulting in oil leakage at the joints of oil pipes and pipe joints.

Operational reasons

Improper operation and poor maintenance are the most direct causes of equipment leakage. If too much oil is added, the transmission shaft of the spindle box of the machine tool is completely immersed in the oil, the computer gong processing, mechanical parts processing, Dongguan CNC machining center, Dongguan high-speed computer gong processing, when the gear rotates, the pressure in the box increases and causes oil leakage; or the vent hole is blocked but not treated, the packing gland is not compacted, and the micro leakage is not treated in time, and the sealing element cannot be replaced after damage If the sealing parts and sealants are not used correctly, there are paint, burr, impurity or bruise on the joint surface of the upper and lower boxes of the reducer, which makes the joint surface not tight. If the sealants are not used after the equipment is sealed, the equipment will leak.

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.

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.

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 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.

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

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.

CNC computer gong programming and processing

Advantages: 1. High reliability

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

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

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

Easy to use and maintain

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

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

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

Easy to realize mechatronics

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

Flexibility and versatility

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

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

Rich CNC functions

Interpolation function: quadratic curve, spline, spatial surface interpolation

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

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

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

Category Archive CNC Technology

Operation process of milling head in CNC machining

How to deal with oil leakage of CNC machine tools

Installation process of CNC machining

The reason why the machining center does not grasp the tool

Processing range of different types of CNC lathes

Decomposition of CNC machining process

Computer gongs processing – Requirements for CNC clamps

CNC computer gongs hobbing

CNC lathe processing

CNC computer gong programming and processing

CNC Machining parts

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