Application and development trend of CNC Turret Punch Press O-305

CNC Turret Punch Press O-305 is an important category of nc machine tools, mainly by the control system, the main transmission system, feed system, the turntable, mold and peripheral components, such as the programming software is a set of machine, electricity, liquid, gas in integration, can carry on the blanking on the board and other forming high speed precision flexible processing equipment.CNC turret punch press, as a key equipment in the field of sheet metal processing, has more than 70 years of application and development history, has become the most important process equipment in automobile manufacturing, construction machinery, hardware, household appliances, computers, instruments and meters, electronic information, textile machinery and other industries.Classification and characteristics of  CNC turret punch machine

According to the power source of the main drive, the CNC turret punch press can be divided into the following three categories:

Mechanical turret punch.This structure has been basically eliminated by the market because of its single motion characteristics, narrow processing range, low stamping frequency, large noise, easy wear of clutch and brake and low life.

The hydraulic turret punch press.This type of product has been the mainstream product in the market for quite a long time in the past.Compared with the mechanical type, its advantage is that the punching process is expanded, the stamping frequency is increased and the noise is reduced.However, it has disadvantages such as oil pollution, high power consumption, poor environmental and temperature tolerance, low reliability and difficult maintenance.

All electric servo turret punch press.With the improvement and promotion of large torque servo motor and drive system in recent years, all-electric servo turret punch press has made great progress and gradually replaced the hydraulic structure, becoming the mainstream product of the industry.

Compared with the traditional mechanical and hydraulic type, the all-electric servo main drive has many advantages:

1) Good versatility and high level of intelligence.Due to the servo function, the punch motion curve is no longer just a sine curve, but an arbitrary curve that can be optimized and designed according to the process requirements, which greatly improves the machining performance and expands the machining range.

2) High accuracy.Encoder on the servo motor to the rotation of the crank Angle information feedback to the CNC system, and then through the punch displacement as a function of crank Angle between processing and can obtain the punch position of real-time data, forming half closed loop control, realize the precise control of the punch movement, bottom dead center precision can be controlled within + / - 0.05 mm.

3) High production efficiency.Servo punch press can adjust the stroke of punch according to the different processing technology.There is no need to complete 360° rotation in a working cycle, but only a certain Angle of swing can complete the processing, which further reduces the cycle time and greatly improves the production efficiency.

4) Energy saving and environmental protection.CNC turret punch driven by servomotor completely depends on the torque of the motor, and the motor rotates only when the punch moves, so the energy-saving effect is very obvious.

5) Low vibration and noise.By setting the speed characteristic curve of the punch, the movement speed of the punch can be reduced appropriately at the moment when the upper die touches the plate, and the noise can be reduced by 8 ~ 12dB compared with the traditional mechanical and hydraulic CNC turbo punch press.

At present, the main servo drive structure mainly has three forms.These three forms of mechanism are mature in technology and have their own characteristics, and they all occupy a large market share.

(1) Double motor driven crank slider mechanism, representative model is Japan AMADA COMPANY'S EM2510NT CNC turret punch.The double motors are arranged symmetrically on both sides of the fuselage, compact and compact, which can guarantee the crankshaft to have enough torque output and obtain high stamping frequency.

The crank toggle mechanism, on behalf of the Japanese MURATEC company MOTORUM - 2048LT CNC turret punch.Although the structure is relatively complex, it can reduce the load torque of the servo motor by using the unique force enhancement characteristic of the crank toggle mechanism. Moreover, the crank rotates once and the slider moves up and down twice, so as to achieve a higher stamping frequency.

(3) The crank slider mechanism driven by a single water-cooled large torque servo motor represents the EP series and H series all-electric servo tower punch of Jiangsu Yangli CNC Machine Tool Co., LTD.Due to the use of a single water-cooled large torque servo motor as the power source, continuous load capacity is strong, there is no dual motor drive synchronization control problem, mechanical efficiency is higher, stability and reliability is better, the product has a very high cost performance.

Typical processing techniques

The typical processing technology of nc turret punch mainly includes blanking and forming.

The blanking process

Blanking process, also known as material separation process, refers to the material to be processed under the action of external forces, along the closed or non-closed contour shear crack and separation.Blanking processing can be directly blanked into finished parts, but also for bending, drawing, forming and other next process to prepare blank.

Generally speaking, blanking process can be divided into the following four modes:

(1) single shot.Punch hole, including linear distribution, circular distribution, circular distribution, grid hole stamping.

The film is moving in the same direction.The use of rectangular mold partial overlap processing, processing can be long holes, cutting edge, etc.When the cutting mode is used, in the process of blanking die stack will deviate from mold cutting load by the center (partial), will cause the torsional deformation of machine tool structure, serious when it might damage the mould, so in the big pore diameter and thick plate cutting load, should as far as possible the reduction of mould amount of overlap, reduce the partial load.

The multi - direction of the continuous impulse.This is a way of using small molds to process large holes, which can increase the flexibility of the machine tool and expand the processing scope of the mold.In this blanking mode, it is usually necessary to rotate the punch at different angles by rotating the station and coordinate with the positioning movement of the feeding mechanism in the XOY plane.

(4) Nibble cutting.This is a type of continuous blanking with small round die at a small step to produce arc or spline curve, is a common processing mode.Because small circle is used for fitting, the contour precision and section quality are usually not high, and the punching efficiency is low. When the punching size is large and the number is large, a special punching die is recommended.

Forming process

Forming process refers to the processing method in which the plate is formed by plastic deformation after the stress exceeds the yield point of the material under the action of external forces. It mainly includes rolling rib, shallow drawing, flanging, bending, etc., and the main forming characteristics and supporting molds of some typical parts.

1 single forming, according to the mold shape of a shallow drawing forming processing method, using this forming mode, the shape and size of the mold must correspond to the characteristics of the processing, and the ordinary press processing mode is completely the same, is a completely "rigid" processing mode.

The continuous forming, forming larger than the mold size of the forming method, such as large size shutter, rolling rib, rolling steps and other processing methods.

Sheet forming process of the material mechanical properties, plate thickness, forming temperature and forming rate of various factors such as comprehensive effect of elastic deformation, plastic deformation involves the anisotropy, strain hardening, material aspects of content, present a highly nonlinear and its forming mechanism is very complex, it is difficult to through the traditional mechanics formula in practical production were analyzed.In the computer virtual environment, the finite element method is used to simulate the material forming process, which can predict and evaluate the elastic rebound, crack and fold in the forming process, so as to further study the forming mechanism.In the industrial production, the finite element analysis can guide the die design and optimize the forming process parameters, which has inestimable practical application value.At present, the commonly used software mainly includes ANSYS, ABAQUS, MAC, LS-DYNA, DYNAFORM and so on.

Future trends

With the development of CNC technology, network technology, servo control technology and large torque servo motor, CNC turret punch press presents the following development trend.

1 high speed, high precision.

High speed, high precision machine tool industry is the eternal pursuit of development, improve the speed and precision of the CNC turret punch press content mainly includes the following aspects: 1) improve the dynamic performance of conveying mechanism, the conveying mechanism with ball screw and gear rack and two main traditional way of mechanical transmission is given priority to, and half closed loop control is adopted to locate the speed, acceleration and location accuracy is usually not high.With the development and application of linear motor drive technology in recent years, linear motor drive technology is adopted to provide real-time motion position feedback through grating ruler to form a closed-loop control, which may improve the positioning speed, acceleration and positioning accuracy of CNC turret punch feed mechanism to an unprecedented height.2) All-electric servo main drive is adopted. On the one hand, its bottom dead point accuracy is high, which can be controlled within ±0.05mm; on the other hand, this drive mechanism has rich stamping modes, such as high-speed crankshaft positive and negative swing machining mode, and the time required to complete a 4mm stroke can be controlled within 40ms.3) Adopt new technologies to reduce downtime as much as possible, such as automatic detection of mold wear, automatic replacement of mold, automatic loading and unloading technology, etc.

The real-time intelligent.

With the development of science and technology today, the market's pursuit of CNC turret punch press is no longer limited to accuracy and reliability, but starts to be based on intelligent solutions.Key technologies: 1) Online workpiece quality monitoring technology;2) Online monitoring technology of mold wear;3) Automatic mold selection and replacement technology;4) Remote intelligent fault diagnosis and troubleshooting;5) Establishment and optimization of process expert database.

(3) Energy conservation and environmental protection.

The CNC turret punch press mainly involves the following three aspects: 1) Noise pollution, which can be processed by silent processing mode, optimized machine structure, sound insulation materials and other methods to reduce vibration and noise;2) Oil pollution, all-electric servo main drive mode to replace the traditional hydraulic main drive mode is the inevitable trend of industry development;3) Based on the green design concept of life, using advanced design concept and design method, strive to make the most rational material application, the machine is no longer stupid thick.

(4) Single flexible processing unit (FMC) and function compound.

Large multi-machine Flexible manufacturing System (FMS), also known as Flexible manufacturing System, is the future development trend. However, in terms of the current domestic market and industrial structure, small single-machine Flexible processing units with complex functions have a better market prospect.This kind of small single machine flexible processing unit takes the CNC turret punch as the main body, has the auxiliary functions such as deburring and tapping, and at the same time is equipped with the three-dimensional warehouse, automatic loading and unloading system, has the extremely high processing flexibility and efficiency, even can realize the unmanned operation.Compared with large flexible manufacturing system, it has small floor space, low equipment purchase cost, better operation reliability and stability, and is more easily accepted by customers, especially suitable for some medium and small professional sheet metal processing enterprises.