Unitech Coreless ST005 automatic pre-stretch rewinder
Unitech Coreless ST005 is an automatic rewinding machine to perform pre-stretch film rolls WITH and / or WITHOUT core (coreless).
The automatic rewinder mod. ST005 works at the average speed of 500 m/min in “Coreless Mode” and at 700 m/min in “Cored Mode”; these speeds may be adjusted depending on the quality and the thickness of stretch film.
The rewinding process is made on a station complete with double arm with automatic change of the roll, cut of the stretch film and exit of the rewinded roll on a powered belt conveyor positioned at the outfeed.
Pre-stretch ratio can be adjusted on the HMI, then elaborated from the PLC controlling the machine, to allow a fine adjustment of the relationship between the pre-stretch rollers. The maximum elongation (until the breaking point of the elastic memory is reached) will depend on the stretch film being used.
All motors are controlled by “inverter” with linked communication through “BUS net”; this system, together with the two dancing arms installed on the group, allow to have the maximum control of the motors and of the stretching tension.
The HMI (touch screen) and all the control devices (such as pressure regulators) are installed on the structure of the machine for an easy and immediate use.
Main operative items:
- Pre-stretch system adjustable from 0 to 500% controlled by PLC. Pre-stretch percentage is done through two powered rubbered rolls (diameter mm. 100) linked through electronic control.
- Distance between the pre-stretch rolls is adjustable up to 60 mm.
- The rewinding process is done in contact with a rubbered roll with adjustable speed up to 750 m/min.
- The rewinding tension is adjustable with automatic compensation made by two dancing arms controlled by a sliding proportional valve electronically controlled by PLC.
- The rewinding process is made on a station with double shaft complete with mandrels, with automatic control of the pressure of the reel on the rewinding roll driven by brushless motor.
- Adjustable air blowers to stabilize the stretch film are installed on the pre-stretch unit and on the rewinding roll.
- Double hot air blowing device to allow a homogeneous distribution of film thickness during the pre-stretch operation.
- Maximum standard diameter of the rewinded roll is 250 mm, with automatic change at the end of the rewinding cycle, stretch cutting and start of a new rewinding process. (please contact us for larger diameter requirements).
- Automatic core loader complete with core magazine (50 or 76 mm).
- Pair of mandrels with diameter 50 or 76 mm and plates for diameter 84 (coreless)
- Outfeed of the rewinded rolls on a powered belt conveyor.
- Pneumatic moving arms to load feed stretch rolls, installed on the back side of the machine; the feed roll is pneumatically centered by two mandrels (diameter of 76 mm).
- Inspection catwalk positioned at the side of the machine.
- Maximum diameter of the feed roll: 600 mm.
- Maximum width of the feed roll: 600 mm.
- Main control board controlled by PLC, asynchronous motors controlled through vectorial inverters and driven by “brushless motor.
- Operating touch screen panel complete with digital display to control:
- Autodiagnosis program and visualisation of the alarms
- Selection of manual operation
- Settings of the rewinding cycle
- Stretch film thickness of the feed roll : 8 - 35 micron.
- Thickness of the rewinded roll: from 5 micron.
- CARBONIUM free rolls.
- Maximum diameter of the rewinded rolls: mm. 250.
- Power consumption: 16 kW.
- Compressed air supply: 6-7 bar.
- Automatic device to detect holes in the stretch film by electronic card and visual/audible alarm without stopping the machine.
- Automatic detection of the end of the feed roll by photocell with automatic machine stop when last roll has been rewinded.
- Rewinding Speed: max 1.200 m/min - average 1.100 m/min.
- Rewinding speed depends on several data: thickness of the stretch film on the feed roll, desired thickness on the rewinded roll, quality of the stretch film used.
Teleservice via Internet is included in the standard configuration of the machine.
- Dispensing system for homogeneous distribution of the stretch film with side-folders to reinforce the rewinded roll
- Additional pair of mandrels for different inner diameters (mm. 50 / 76 / 110)
- Load cell to detect the weight of the rewinded roll installed under the powered belt conveyor (tolerance +/- 10 grams)
- Motorized device for centring the jumbo reel from the operator's panel (only for rolls with cardboard core)