Product station film stretching line
This station shows part of a film stretching line in test operation - the inlet and outlet area of a transverse stretching unit (TDO), also known as an oven. In this section, the film passes through the oven, where it is stretched crosswise and brought to its final dimensions. The clips developed by DORNIER take over the guidance of the film: they grip the film, pull it through the oven and then open again at the right moment. The movement is precisely controlled, even at high speeds and under demanding process conditions. The setup shown is used for online presentations to demonstrate the latest technological developments in DORNIER film stretching systems in a clear and practical way.
How does a film stretching line work?
The starting material is plastic granulate, which is stored in a silo system and melted in an extruder to produce a liquid plastic melt.
The molten plastic, which resembles liquid honey, is poured through a wide-slot nozzle, creating a uniform, flat casting film that solidifies on the internally cooled casting roller. The largest casting roller we have supplied to date had a diameter of 4.2 m for a special application. A diameter and width of 3.5 meters are common.
In the MDO (Machine Direction Orienter), the solidified cast film is reheated by heated rollers. As soon as the temperature required for stretching is reached, the film is stretched lengthwise by rollers at different speeds. A longitudinal stretch consists of heating, stretching and cooling zones. The film is passed through different zones in several successive steps in order to stretch it lengthwise in a controlled and damage-free manner. The rollers in the heating and stretching zones are heated with thermo oil, hot water or steam. Finally, the film is cooled by rollers that are tempered with water or thermo oil.
In the transverse stretching oven (TDO), the film is guided through the oven on chain conveyors through several precisely controlled temperature zones using two endless chains with grippers - the clipper chains that hold the film at the edges. There it is stretched crosswise to achieve its final properties.
In the take-off unit, also known as the transfer section, the film is cut to its final size. The side edge strips are removed and recycled directly in a shredding mill. The surface of the film is also treated here - for example by corona or flame treatment - to change the surface so that it is suitable for further processing steps such as printing or laminating. Another important step in this area is thickness measurement: the film passes through a measuring system that records the thickness profile and thus ensures consistent quality.
In the final step of the process, the finished film is rolled up on the winder. As soon as a film roll is full, the roll is changed - without interrupting the ongoing process. The system has two winding stations. When one roll is full, the second station is moved into position and takes over the winding process. The film is then cut using a cutting device and transferred to the new, still empty winding core, where the winding process continues.
Zahlen, Daten, Fakten
24/7 top performance
Our film stretching lines are designed for continuous operation around the clock: 24 hours a day, 7 days a week, around 50 weeks a year.
From ultra-thin to ultra-wide
Our systems enable the production of extremely thin films - down to 0.8 µm (0.0008 mm), i.e. 60 times thinner than a hair. At the same time, they offer the capacity for film widths of up to 10.6 meters - for maximum efficiency and format diversity.
From Lake Constance to the Danube on one roll
Our systems wind an impressive 96,000 m of film onto a roll with a film thickness of 12 µm - the equivalent of 96 kilometers from Lindau to Ulm. The finished wrap measures 1,480 mm in diameter, weighs up to 25 tons and is completely filled in just 2.5 hours at a line speed of 600 m/min.
Around the world seven times a year
With the annual output that a single one of our systems can achieve at 12 µm film thickness, our customers could wrap the earth almost seven times with film - a strong statement for the performance and endurance of our technology.
This can be produced on our film stretching lines
Packaging films
Food packaging
From snacks to delicatessen – our technology keeps products fresh for longer.
Pharma & Medicine
Hygiene, safety, durability – in this sensitive area, quality and precision count down to the smallest detail.
Care & cleaning
Durable packaging films reliably protect hygiene products and preserve their cleanliness.
Labels & shrink film
Shrink films adapt perfectly to the product and are often used as labels to create an appealing design.
Technical films
Capacitor film
In electronic components, special plastic films enable reliable energy storage in capacitors.
Battery separator film
In lithium-ion batteries, extremely thin separator films ensure the separation of anode and cathode with simultaneous ion transport.
Solar backsheet film
In photovoltaics, backsheets protect sensitive solar cells from the effects of weather and UV radiation.
Display film
Modern displays use transparent functional films that meet the highest standards of optical quality.
Stations
Experience our plant Esseratsweiler virtually
Die construction
One and two-part nozzles for precise heat supply in the oven of the film stretching line.
Technology Center Composite Systems
Technology center for machines and systems in the composites industry.
Training workshop
Qualified training for future specialists with a focus on construction mechanics.
Flame cutting system
Cutting with multiple torches for high quantities and material thicknesses.
Frame and web girder construction
Production of the stove with frames & web beams and brackets.
Warehouse & Logistics (myDoX®)
Organization and control of spare parts and components for film stretching lines.
Assembly of film stretching systems
Efficient preparation and assembly of individual assemblies.