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At present foreign production CNC turret punch manufacturers have a lot of, here also includes a number of famous manufacturers in other countries or subsidiaries. Since the advent of numerical control, turret punch 30 years, with the development of NUMERICAL control technology, hydraulic and pneumatic technology, moving components and computers, and other related technologies, the rapid development of numerical control turret punch (most manufacturers of high-grade models of technical indicators and functions), greatly beyond the imagination of most users. The products of each manufacturer constantly bring forth the new, wonderful, which is not only to evade the existing patent technology but also to display individual technology, in order to compete for the market.

The rapid progress of CNC punch technology has driven the development of its auxiliary machine, and the emergence and popularization of a flexible sheet metal processing system (FMS) are also closely related to this. We can understand the development trend of CNC turret punch by investigating the structure and technical indicators of CNC turret punch.

Structural Improvement of CNC Turret Punch

CNC turret punch press can be divided into different types in terms of the structure according to the form of bed, control shaft number, mold library, main transmission mode, etc. According to the form of bed can be divided into open C shape or J shape, closed O shape; According to the number of control axis can be divided into 3 axes or 5 axes; According to the mold library can be divided into turret type, knife library type, in-line type, array type; According to the main transmission mode can be divided into crank slider type, mechanical CAM type, toggle servo type, hydraulic type.

• Regardless of whether a bed is open or closed, its technical performance is either advanced or not. When the nominal force is below 400kN, the performance of the machine tool is basically not affected by the two bed forms. In manufacturing, user operation observation, open bed is better than closed. Of course, when the weight of the bed is the same, the closed bed is more favorable to reduce the deformation of the machine tool. Although most manufacturers are currently in the production of open bed CNC turret punch, but it can not be said that this is the development trend of CNC turret punch, and then deny the closed structure. AMADA and KOMATSU use dual construction to improve machining accuracy and die life.

• The X and Y axes feeding into the positioning of the plate and the t-axis of the die selection axis are the three basic CNC axes of CNC punch press. A CNC punch made by Trumpf in Germany with a straight line of moulds on an X-axis beam and a CNC punch made by Salvagnini in Italy with an array of moulds are special cases. The former selection axis and X axis are combined into one, the latter has no selection axis only two axes. Regardless of these two special cases, the fourth axis of CNC punch is the C axis of the die axis, and the fourth and fifth axes are the C1 and C2 (following axis) axes of the die axis. At present, manufacturers have basically no longer produce 3 axis or CNC punch without turning die. Rotary spindle will no longer be optional for CNC turret presses, but a basic feature.

• Static turret die library has always been the mainstream mode of CNC punch die library, which features simple structure, large capacity, reasonable die structure, quick die change and easy assembly and disassembly. Punch knife library type mould library is derived from the knife library and knife changing mode of gold cutting machine tool, now only Italian Omes company, Whitney company in the United States, Trumpf Company in Germany has eliminated the knife library type structure and unique invention of the in-line mould library. Salvagnini Italy company original array mold library. The above three manufacturers in the process of product development have improved their own structure, to meet the needs of the vast majority of customers, but in some aspects, each has its shortcomings, such as long mold change time, small capacity, adverse mold layout. Some manufacturers have developed an external mold library to reduce artificial auxiliary time to improve productivity or make up for the lack of small mold library capacity, but this is not the problem of CNC turret punch itself.

• The main drive part has always been one of the symbols of technological progress of CNC turret punch. The punching frequency of the main drive directly affects the production efficiency of CNC punch, so it becomes the focus of attention of manufacturers and users. From the original crank slider mechanism plus pneumatic clutch brake or hydraulic clutch brake main drive, developed to the present high frequency, low noise, performance of the hydraulic main drive system.

The complex mechanical cam-type structure, which is only a variation of the crank slider mechanism to reduce noise, is patented by the Japanese company Amada.

Toebar servo’s main drive is the original invention of the Japan Murata company. It innovatively uses a servo motor to drive Toebar mechanism to easily control stamping frequency and speed, and for this reason, it won the Design Award of Japan machinery industry in 1995 Tsukuba Machine Tool Exposition — Minister of Industry Award. This toggle servo main drive, the mechanism is more complex, the performance is not superior to the hydraulic main drive.

The hydraulic main drive system is composed of a fast hydraulic cylinder, control valve block, and hydraulic station. The key lies in the multi-point control of the up and down stroke of the cylinder and the rapid reversal. The smooth hydraulic system, easy speed regulation, controllable stroke, overload safety protection has been fully reflected in the CNC punch, and has brought unprecedented technical progress for CNC punch:

1. The noise is greatly reduced, basically only the sound of plate breaking.
2. Vibration is greatly reduced.
3. Increased stamping frequency, up to 1200 times /min.
4. Adjustable punching modulus reduces the time of mold adjustment.
5. There is no phenomenon of overloading and stuffy car even causing damage to parts.
6. Slide block can be kept in any stroke position, CNC punch can complete rolling and rolling shear process.

It can be seen that the hydraulic main drive to replace the mechanical main drive is an inevitable trend, the current output of the mechanical main drive CNC turret punch is in rapid decline.

CNC System Development And Secondary Development

The numerical control system is an important part of the numerical control turret punch. The progress of numerical control technology and computer is the premise of improving many technical indexes and realizing functions of numerical control turret punch. Most of the NUMERICAL control system uses 32-bit CPU to greatly improve its processing speed. Increased memory capacity; Many functions realized by external electrotype-mechanical combination began to become the functions of the numerical control system, greatly simplifying the electrotype-mechanical structure and improving reliability; The man-machine interface is more friendly. Numerical control system and the computer closer and closer, with the hard disk, Windows operating system for the platform more convenient host manufacturers personalized development, use more convenient.

Some famous CNC turret punches manufacturers through the external purchase of CNC system for secondary development so that it can more with the characteristics of machine tools (some of the automatic programming software embedded in the CNC system to make the field programming is very simple). Finn-power’s three-clamp program-controlled automatic transposition function ensures that the precision of the parts is not affected by repositioning, thanks to the speed and convenience of the CNC system.

The secondary development of numerical control systems and the innovation of machine tool structures can also make the operation more simple and convenient. Such as the system has the discharge display, real-time display of the processing process, automatic programming, clamp position programming, machine tool operation data statistics (stamping times, running time, mold use times, etc.), perfect fault diagnosis and other functions; Mechanical aspects of the continuous emergence of auxiliary mold lifting device, mold oil mist lubrication, automatic lubrication of motion pair, small channel, vacuum suction waste, hydraulic main transmission, multi-mode and multi-mode device, and other new devices and new structures, so that the operator of the machine intervention and maintenance is less and less, the non-production time is shorter and shorter.

CNC Turret Punch Technical Indicators Improved Significantly And Continuous Improvement

CNC turret punch is a high speed and high precision plate gold stamping equipment, its development direction to improve productivity as the primary goal, the other need to continue to increase the function, continue to expand the scope of technology, improve the degree of automation, improve the operation to make it more pleasant.

High-speed starting and braking, high-frequency stamping, high precision positioning at the same time requirements of CNC punch is quite harsh, but the technical indicators of CNC turret punch in recent years continue to improve. Most manufacturers have reached the highest index: mold change time is shortened to 1~2s; The stamping frequency is 900 times /min, up to 1200 times /min (Salvagnini Mold array S4 system), 25mm step stamping frequency is 450 times /min; Uniaxial feed speed up to 100m/min; The spacing between adjacent holes (within 300mm) is ±0.07mm.

In order to achieve these objectives, various measures have been adopted, such as Amada and Komatsu’s dual frame construction to improve machining accuracy (±0.07mm) and die life. The Y-axis of the Rainer machine tool adopts bilateral drive, which enables the table to accelerate 8~10m/min and can press at 100 ~900m speed.

The appearance of the rotary die device and the unique design of the die makes the scope of CNC punch processing technology continues to expand, in addition to punching, undulating molding outside arbitrary rolling shear, rolling rib, a large range of deep drawing, and other new technology can also be realized on the CNC punch. This technological development greatly exceeds the expectation of user demand, which is the embodiment of the technical strength of well-known foreign manufacturers, but also the fundamental reason for their leading position in the market competition.

Automatic programming software also began to become a part of CNC turret punch, its function affects the user’s evaluation of the host. Users began to demand automatic programming software with 3d deployment, automatic layout, multi-data statistics, and other functions.

Future Development of CNC Turret Punch Press

Manufacturers of CNC punch high speed, high efficiency, high precision pursuit, does make its technical performance has been constantly improved, but this makes the operator become an obstacle to the performance of machine tools. This is because the manual completion of the loading and unloading and mold replacement operation occupied too much auxiliary time, the operator became a slave of machine tools, more and more not to adapt to the high productivity requirements of machine tools. Therefore, punch automatic loading and unloading device, external mold store automatic die changing device to become a part of the efficient CNC punch has been put on the improvement agenda. For example, Komatsu’s APO3048 stamping center has up to 300 sets of molds built-in; Most manufacturers have different grades of loading and unloading devices, and some are even multi-axis NUMERICAL control devices. Thus, the continuous improvement of numerical control punch technical performance and function should be based on the development of related technologies and the emergence of new structures as the premise, and ultimately to the expansion of the machine (increase auxiliary machine) as a result.

Throughout the status quo and development of CNC punch, it can be considered that:

1. Mechanical main drive is eliminated by the hydraulic main drive has become a foregone conclusion.

2. Stamping (or compound) center without intervention is the development direction of CNC turret punch.

3. The increasing speed, open and reliable industrial computer is more adopted.

4. With the development of NUMERICAL control technology, servo technology, and moving components, especially the maturity of linear servo motor and the reduction of cost, the structure of numerical control turret punch press will have new breakthroughs. For example, the clamp can be directly connected with the moving part of the linear motor, without linear guide rail and ball screw, so as to simplify the structure, reduce the inertia of motion, and further improve the feeding speed; The grinding of the mold can be completed on the machine without assembling and disassembling the mold; Linear servo motor can replace the existing hydraulic main drive.

5. Develop the application and popularization of remote diagnosis technology. The development of network technology and numerical control systems will make it possible for manufacturers to remotely diagnose and repair their machine tools all over the world.