Slip shaft

Slip shaft

Slip shaft, also known as friction shaft. It is used for the winding shaft of the slitting machine and also for the unwinding shaft in special occasions, so as to
Based on the principle of slip of each slip ring on the slip difference shaft, multiple reels on the shaft can always be reeled in and out with constant tension.
The slitting machine is a kind of equipment that splits a roll into multiple rolls. It is widely used.
The function of the winding shaft is to evenly and orderly wind the multi roll materials after various materials are divided into strips on one or two shafts at constant tension from the core to the outer layer. However, due to the uneven thickness of the material itself, there is a certain thickness error. After continuous coiling, each coil diameter will produce greater accumulated error. This leads to a greater difference in the coiling speed and tension of each strip.
As a result, the tightness of the coil is not uniform, and the end face is uneven. In serious cases, the material is damaged and scrapped due to excessive tension, especially the polyester film, which not only has a large thickness error, but also has a large elongation, so it is easy to stretch and deform and cause waste products.
The slip shaft has a special structure and is composed of multiple slip rings, which can overcome the above phenomena. During operation, the slip ring is controlled to slip with a certain value of slip torque (torque), and the slip amount just compensates for the resulting speed difference, so as to accurately control the tension of each roll of material and ensure the coiling quality with constant tension.
With the improvement of people's living standards and the development of science and technology, higher and higher requirements are put forward for flexible packaging products. The requirements for the elongation of the film are getting smaller and smaller, and the evenness of the winding end face is getting higher and higher, which puts forward higher requirements for the tension control of the material film.
The tension control accuracy of the winding shaft directly determines the elongation of the slitting product and the evenness of the end face, so it is necessary to use the slip shaft.
With the use of slip shaft, the speed of the slitter, the winding accuracy, the degree of automation and the preparation time are reduced, and the humanization of the operation is improved. In particular, slip shafts are used for cast polyester thin materials with poor tensile elongation and large thickness error,
The difficulty of rolling is reduced.
The application of slip shaft winding for precious metal foil can greatly improve the quality rate and reduce the production cost.
Special production costs. Special paper is the first application of this technology.
Slip shaft has been widely used in plastic film (including electronics, capacitors, battery film, fresh-keeping film, packaging, composite film); Metal foil (copper foil, aluminum foil, etc.); Paper roll; Cutting and winding of PVC sheets and rolls. At present, it is continuously extending to other fields, other industries, and the slitting and winding of other special materials.
The forms of coiling include center coiling, surface coiling and surface center coiling. The following focuses on the central coiling and receiving shaft,
There are four main structural forms:
Center air pressure slip shaft,
Differential pressure and slip shaft at pneumatic side,
Mechanical side differential pressure shaft,
Air expansion shaft.
（1） Center air pressure slip shaft
It is a tension adjusted slip shaft, and the slip ring slips independently. Controlled by the tension system, the shaft core is supplied with compressed air under a certain pressure,
The friction torque is generated between the shaft core and the slip ring through the friction parts, so as to achieve constant tension coiling. It can be applied to the range from very low tension to the highest tension, and is applicable to the requirements of high speed, large material thickness error, multi section tension control, high tension control accuracy, and neat end winding.
It is most suitable for the use of double axis central coiling slitter.
The central pneumatic slip shaft is divided into pneumatic locking type and mechanical locking type.
The central pneumatic slip shaft is composed of mandrel, slip ring, air bag, friction parts, sealing ring, etc.
1、 Start the locking type central pneumatic differential slip shaft,
It is the slip shaft with the highest performance. It can lock the core coil and generate friction torque during ventilation. It can realize full automatic unwinding, forward and reverse coiling, and no film breaking or unwinding during coiling and no offset.
Representative products:
Japan extends the slip axis to the east and the slip axis to the west. Its control accuracy is high and the cost is relatively high.
2、 Mechanical locking type central pneumatic slip shaft.
Friction torque is generated by air pressure, and core locking is completed by mechanical eccentricity.
Representative products: ball type sliding differential shaft, sheet steel sliding differential shaft, non-ferrous sliding differential shaft, key type sliding differential shaft, tooth type sliding
Differential axis. Germany, Britain, Italy and other European countries mostly adopt this structure. Some factories in Taiwan and Japan
Home also adopts this structure.
Features: stable performance, strong adaptability, durability, and relatively low cost.
（2） Pneumatic side pressure differential shaft
Differential pressure and slip shaft at pneumatic side,
The principle and structure are basically similar to the mechanical side pressure slip type winding. The difference is that the compression spring is changed to the cylinder compression, and the compression pressure can be adjusted digitally. The constant tension error is large when equipped with an electro pneumatic converter. If one slip ring fails,
Defects that will lead to uncontrollable tension of the rear slip ring.
The advantage is that large air pressure can be applied by pressing the cylinder, so as to achieve high torque and high friction tension coiling.
（3） Mechanical side pressure slip ring
The mechanical side differential pressure shaft is mainly composed of a mandrel and a plurality of slip rings sleeved on the mandrel.
Both ends of the slip ring are made of friction materials, and a metal spacer ring is installed between the rings. The slip ring is closely attached to the end face of the spindle by the end face compression spring,
The spindle rotates under the drive of the motor, drives the slip ring to rotate under the action of the end friction, drives the core of the take-up cylinder and the coil fixed on the slip ring to rotate, and completes the multi winding function.
In order to control the tension and friction heat generation, there is a diameter detection device to make the linear speed of the reel surface driven by the take-up mandrel faster than that of the host machine
Rotate at a speed of 5~10%. Under the action of slip ring, the material is wound on the receiving shaft at the set tension value.
The reeling applicability of this method is greatly improved compared with that of the air expansion shaft, and it is suitable for reeling materials with low speed (200M/MIN), certain thickness error, less reels and moderate tension. The disadvantage is that only constant torque control can be achieved, the tension error is large, and it can not adapt to high speed. The tension consistency is poor when multi winding. The biggest disadvantage is that tension adjustment can not be achieved during winding.