Contech Custom Sheeter Stacker
The system is composed of three main modules, the Unwind modules, the Sheeter module and the Stacker module.
Material Unwind Modules
Each unwind module consists of an inflatable support shaft, two safety support chucks, a magnetic particle brake, a pneumatically actuated dancer/accumulator, an end of roll sensor, a material splice station, and a self-contained automatic web guide.
As material is pulled from the parent material roll, tension on the material web causes the dancer to begin to swing forward while the pneumatic cylinders attempt to resist this motion. At the same time, the dancer position encoder senses this movement and sends a signal telling the mag brake to release thus allowing the parent material roll to begin unwinding more material.
Once the tension of the web is overcome by the resistance provided by the dancer cylinders, the dancer swings back to a stable position providing a stable web tension. As the web tension decreases, the dancer moves back, and more brake is automatically applied to the parent material roll… always trying to maintain the dancer in “mostly” vertical position(as shown). The relationship between the dancer and the mag brake is essential in establishing a smooth stable material web for the sheeter to process accurately and at the fastest speeds possible.
If the parent roll is not properly wound, the edge of the material will tend to “wander” as it is fed from the unwind. To help prevent this wandering from leaving undesirable effects at the sheeter or stacker, an automatic web guide can be used to relocate each unwind module laterally thus maintaining the edge of the material in a stable location relative to the rest of the machine.
When a parent roll has been depleted, the end of roll sensor triggers the machine to stop processing so the old roll can be changed for a new one that can be “spliced” to the tail of the existing web at the splice station.
The sheeter consists of a servo driven increment roller and positive stop nip roller, a pneumatically biased down acting cutter blade set, a three station driven slitter mandrel with Tidland Class I slitters, two Meech static control bars, custom dust removal system, and an Allen Bradley touch screen interface for entire system controls.
The sheeter uses an increment roller to feed a single layer or dual layers of material from the unwind modules through a series of idler rollers and across a stationary lower blade where the material web can be cut to any given length… at any given speed… any number of times… that is programmed into the system controller.
When running a single layer of material, that layer can also be slit to any given width in addition to being cut to length. The sheeter’s servo increment drive can be programmed to accelerate and decelerate at different rates, maintain peak velocities ranging from 1-100%, as well as prefeed distances to allow for better gripper clamping on the leading edge of the material.
The gripper is a servo driven “clamp” that grips the leading edge of the material web exiting the sheeter and pulls the material as it is incremented by the sheeter. Once the material has been cut to length, the gripper slowly pulls the material from the blade and onto the stack cart where it releases the material and accelerates back to the sheeter to grip the next sheet. As sheets of material accumulate on the stack cart, the stack height sensor detects when the stack is too tall for safe operation and sends a signal telling the stack table to lower the cart. When the stack cart is full or when the batch count has completed (whichever comes first), the table will lower the stack cart to the ground and machine operations will cease until the material and cart have exited the machine.
The gripper has the capability to stack material to close tolerances… even when slitting. The gripper also has the capability to collate or “stagger” a given number of sheets within the stack and at a given stagger distance.