Servo turret punch is a compound sheet metal processing machine adapting to the development of the times, which occupies an irreplaceable important position in the sheet metal industry.
At present, although the laser cutting machine has developed rapidly and occupied a certain market share, due to its own limitations, it does not replace the position of servo turret punch. Servo turret punch still has many advantages in sheet metal processing.
Development of servo turret punch
Punch has a long history of development.
Today, there are generally three types: mechanical punch, hydraulic punch and servo punch.
After long-term market verification, the crankshaft structure of mechanical punch is the main force.
The hydraulic press uses high-pressure hydraulic oil to act on the piston to promote the reciprocating movement of the piston to form a stamping action.
The punching pressure is adjusted by the pressure of hydraulic oil.
Servo punch is based on mechanical punch.
Various mechanical transmission structures have existed, such as crankshaft structure, connecting rod structure, etc., or it is not a simple structure, but a composite structure with multiple structures at the same time.
Crankshaft structure punch.
The middle crankshaft part has simple structure and is easy to process, which is an advantage, but the disadvantage is also obvious.
It has a nominal force stroke, and the design impulse pressure can be reached within the nominal force stroke range.
Outside the nominal force stroke range, the crankshaft cannot exert force, so it can not meet the service conditions, resulting in the inability to punch through the iron plate and the phenomenon of holding.
After holding, it is difficult to deal with.
Holding will cause irreversible damage to the mechanical stability.
The application of connecting rod mechanism in punch has changed people’s traditional understanding of punch and innovated people’s concept.
The design of linkage mechanism is more flexible, and the layout of accessories can be more reasonable.
The simplest aspect is that it can set the length of the force arm, so as to change the impact force and give full play to the advantage of the lever.
“Give me a fulcrum and I can pry the earth”.
For punches with different tonnage in the same series, the data adjustment in design is also more convenient, which is unmatched by the crankshaft structure.
The hydraulic system is applied to the punch, which has revolutionized the punch at the beginning of its emergence.
The pressure of the hydraulic punch is constant in the whole stroke range, and there will be no nominal force stroke problem of the crankshaft structure punch.
In this way, it can punch some thick plates, large holes and deep draw thick plates, because stamping these thick plates requires a lot of punching pressure.
This advantage of hydraulic punch is unmatched by other types of punch.
Some people still stay on the inherent concept of hydraulic pressure in the early stage and think that the hydraulic punch is slow, which is the characteristic of large-scale hydraulic special machine.
Now the hydraulic punch of about 30t adopts high-quality hydraulic valves such as servo proportional valve, equipped with high-quality controller, and the stamping frequency can reach more than 1000 times / minute, which can greatly meet the needs of sheet metal production. However, the biggest disadvantage of the hydraulic system is that the oil pollution is unacceptable.
With the in-depth development of the manufacturing industry, the sheet metal industry needs to carry out fine division of labor, such as the separation of thick plate and thin plate, iron plate and non-ferrous metal plate, flat hole and deep drawing hole, etc.
After separation, different machines and equipment are used to process, and the quality and efficiency are greatly improved.
In this situation, servo turret punch came into being.
Advantages of servo turret punch
High speed, high precision and cleanliness are the biggest advantages of servo turret punch.
At the source of kinetic energy generation, the mechanical punch uses an ordinary motor to drive the large flywheel to rotate continuously, and drives the crankshaft to rotate through the clutch to form a reciprocating motion, so as to realize stamping.
The punching pressure comes from the inertial force generated by the high-quality flywheel rotating at high speed.
The clutch mainly includes hydraulic clutch and pneumatic clutch.
In principle, the crankshaft servo punch eliminates the ordinary motor, flywheel and clutch of the mechanical punch, and installs the high torque servo motor on the machine body to directly drive the crankshaft to rotate, form reciprocating motion and realize stamping.
In fact, the servo motor does not rotate continuously in one direction, but intermittently reverses and swings at high speed at the left and right positions near the bottom dead center.
It does not have to return to the top dead center to waste time.
It directly starts punching from a relatively low position, so as to realize high-frequency punching. The punching pressure is determined by the torque of the servo motor.
Sometimes, in order to reduce the cost and installation size, a small torque servo motor will be used.
At this time, in order to achieve the required punching pressure, another reducer needs to be configured to increase the torque, so that the punching speed will be reduced.
As a sliding bearing, copper sleeve is widely used in punch press.
Copper sleeve is basically used in each rotating joint.
The copper sleeve can play a good supporting role because it is face-to-face contact and the stress mode is face-to-face stress.
The advantages are large stress surface, large bearing capacity, not easy to be damaged under normal use and long service life.
Of course, there are disadvantages, that is, there is a certain friction, which will lose a small part of power.
In order to adapt to the development of high-speed punch, bearings are used instead of copper sleeves in some rotating joints of punch, which has the advantage of reducing friction and power loss.
However, the disadvantages are also obvious.
When the bearing is subjected to impact force, it is point or line force, that is, the steel ball or roller directly impacts the inner and outer rings of the bearing, which is easy to cause damage. Therefore, it is impossible to bear large impact pressure.
But for high speed, there must be some trade-offs.
For the servo turret punch press, it is a punch press specially designed for thin plate.
Most of them are less than 30t, and the use of bearings will not have an adverse impact on the punch press.
The servo press uses the power of the servo motor, has various functions such as speed change and execution, and has the characteristics of good controllability of speed.
It directly drives the stamping mechanism, and uses adaptive torque control technology, computer control technology, digital technology and feedback control technology to control the operation of the servo motor.
It can accurately control the position of the stamping head relative to the motor angle, and use the stamping mechanism to realize a variety of stamping processes.
By compiling different programs, various stamping motion curves required by the process are realized, different workpiece deformation speeds are obtained, the workpiece quality is guaranteed, and the service life of the die is improved.
It is an environment-friendly and energy-saving press, realizes the digital control of the press, and makes the press truly enter the digital era.
Compared with the traditional press, the characteristics of the servo press are as follows:
(1) It can effectively improve the production efficiency, and its stroke length can be set to the minimum value required for sheet metal processing, so as to realize the forming speed corresponding to the processing content.
(2) The product has high processing accuracy, which can always maintain the accuracy of the bottom dead center, avoid rough edges and prevent bad products.
(3) Low noise of equipment and long service life of mould.
The machine equipment is equipped with noise reduction device, which makes the stamping soft and greatly reduces the noise pollution;
At the same time, the stamping distance between the die and the plate is controlled to minimize the working stroke of the die, so as to prolong the service life of the die and greatly reduce the use cost.
(4) The movement of the punch is controllable.
Users can use this feature to compile the movement mode of the pressure head suitable for the requirements of sheet metal processing, effectively improve the processing accuracy and product quality stability of parts, improve the service life and productivity of the die, and realize silent blanking, and even expand the processing range, which is suitable for blanking, deep drawing, embossing, bending and other processes, as well as the characteristic curves of different materials.
For example, the stamping head can be stopped to maintain the pressure, so as to realize the manufacturing process of rolling rib and rolling table, and greatly improve the forming quality of sheet metal parts.