In October 2004, Austrian SML Lenzing delivered a world-leading modern stretch-wrap film production line to Orbita Film GmbH, a European manufacturer of stretch-wrap film in Weißandt Gölzau, Germany, with a production speed of 600m. /min, the output per hour is 2000kg/h. The commissioning of this production line has increased the company's annual production of stretch film from 100,000 tons to 115,000 tons, which is regarded as a very economical high-performance production line.

â—† Austrian SML Lansing Company According to Mr. H?ndel, General Manager of Orbita Film GmbH, Orbita Film GmbH is a specialized manufacturer to supply the market with a wide range of special stretch film widths from 250mm to 700mm. There is an urgent need for a production line that is versatile and can often change the width of the film in a very short period of time. SML Lenzing Company put the line into operation in only four weeks. He believes that the production line not only satisfies these requirements, but also has many unique features. It is a very economical high-performance production line.

This line shows the following superior performance in terms of technology and economy:
● The actual production speed reaches 600 m/min.
The production line consists of five extruders and can produce 2000 kg of 5-layer stretch film at a width of 2500mm per hour. According to the width of the production line, the maximum extrusion volume is 4500kg/h, and the annual output can reach 36,000 tons. The high-standard, high-volume production lines provided by SML Lenzing ensure the processing scale, efficiency and profitability of the processing companies.
● The edge packet structure guarantees stable and continuous production. The production line adopts a die-packing system, which reduces the necking of the film and ensures the stable production of film products at high speed. Even when the raw material or product thickness of the product is frequently changed, the system can ensure the stability of the film edge. The reason why SML Lenzing adopts this system is that a modern production line must satisfy the user's various needs, for example, to produce a very small product order, which requires frequent replacement of production process recipes. If there is no packet system, the edges of the film will become very unstable. The packaging system always puts the same raw material (such as LLDPE) on the edge of the film, so that the melt at the edge of the die is always in the same production environment.

● Film thickness from 12 μm to 50 μm
The market's demand for stretch-wrapping films has increased year by year. At the recent international conference on stretch-wrapping films held in Cologne, Germany, most participants believed that the current annual growth rate of the demand for stretch-wrap films is 5 to 7%. Demand for the European market is 1 million tons in the year, with manual stretch film accounting for 40%, medium stretch film 48%, and high stretch film 12%. Its thickness is generally between 12 μm and 50 μm. SML Lenzing's stretch film production line fully meets this thickness range.

●The product structure is flexible. The adhesive layer can be in the inner layer, the outer layer or both. The film winding angle can be adjusted. At present, the production process of the stretched and wound film is more and more complicated. A typical example is that the adhesive layer can be in the film. The inner or outer surface of the film is even located on the inner and outer surfaces of the film. During production, some air is also entrained along the surface of the film into the reel being wound, which can adversely affect the quality of the reel. The higher the speed, the greater the negative effect. Due to the different locations of the adhesive layer, the roughness of the inner and outer surfaces of the film is different, which affects the amount of air entrained on the inner and outer surfaces. In this regard, SML Lenzing Co.'s winders use a special planetary roller system that adjusts the winding angle of the film relative to the contact roller to prevent air ingress, eliminating the need for air entrainment to wind up the film. The negative impact.

● Overcoming the limitation of 3in(1in=25.4mm) reel's critical rotational speed under high-speed production With the birth of new resin, the bottleneck problem of high-speed production is no longer an extrusion problem, but a winding problem. In fact, all winders on the market today operate at critical speeds below the 3in reel, and cannot cross critical speeds, thus limiting the development of the line to high speeds.

SML Lenzing's winder successfully solved this problem. It adopts the horizontal rail design of two rewinding stations. The 400mm thick side walls on both sides are equipped with numerous anchoring piles and filled with concrete. Any vibration will be immediately transmitted to the anchoring piles in the side walls and pass through the concrete. Damping is attenuated. Therefore, with this winder, there is no problem of the critical rotational speed of the 3in reel, and it can automatically and smoothly cross the critical rotational speed.

This is the only winder in the world that can use the 3in reel to exceed the critical speed or over 700 ~ 800 m/min. It has become the new winding technology of SML Lenzing. milestone.

● Film roll diameter up to 450 mm (using 3in reel) or 800 mm (using 6in reel)
In Europe, there is a tendency to produce huge mother rolls first and then rewind them onto 1.5-in or 2-in paper cores, especially when producing artificially packed films. The SML Lenzing line can be wound up to 450 mm in diameter (using 3 in reel) or 800 mm (using 6 in reel) and can convert 3 in and 6 in reels in minutes. To obtain a hand-stretched stretch film, the stretch film on the parent roll can be re-wound onto a paper core having a diameter of 1.5 in or 2 in.
Due to the advantages of SML Lenzing's stretch-wrapping film line with the ability to quickly change take-up reels, Orbita Film GmbH currently increases the proportion of 700-mm diameter rolls produced with 6-inch take-up reels. They operate this way because a large parent roll can extend the unwind time during rewinding and reduce the number of downtime changes, thereby saving frequent shipping and rollover time. According to statistics, with a large parent roll, a rewinder can save about 60 hours of wait time for roll-off change in a month.

● When changing the roll, no waste film is produced. When the roll change is not required, the new roll is automatically changed by a special blue basket that is compatible with the 3in and 6in take-up reels. No tape, glue, or electrostatic device are required to assist the roll change. . No loose or misaligned film will be produced when the film is cut. This is because the new rewinding station is only a few millimeters away from the contact roll. When the film is cut, ultra-light carbon fiber contact rolls with extremely high dynamic sensitivity can press the film against the new reeled paper core in 1/1000th of a second. , thus completing the non-waste film replacement. In this way, product film rolls do not need to be sorted and packaged directly from the factory, which greatly reduces the amount of waste film produced and reduces production costs.

● In the production process, the width of the product can be changed very flexibly. According to the specifications of the market, the width of the normal stretch-wound film is between 250 mm and 700 mm. The winder can quickly and easily change the width of each film roll. The 9 cutters equipped with the winder can divide the entire film roll into 10 small film rolls with a width of 250 mm, and no additional support device is needed in the middle of the take-up reel. The operator can easily change the width of each film roll in a very short time, for example from five 500 mm film rolls to four 450 mm / 1100 mm / 500 mm / 450 mm film rolls and vice versa.

●Independent edge trimming pellet recycling system for rapid change between different colors or with the colorless packaging machine'target=_blank>transparent film. Some customers often need some different color stretch film, the most important is black, Be blue, white, and orange. As these orders and demands increase, it becomes more and more important to reduce the cleaning time during equipment replacement. Therefore, it is necessary to replace the traditional cut-grind-direct feed-back system with a new pellet recycling system.

For the conventional vertical recycling device, since many scraps of raw material are accumulated in the entire system, it is not possible to completely complete the return of the raw material in a short time. At the same time, the edges of the film are heavier and it takes more time to clean the system to eliminate the different colors on the edges of the film. That is, the conventional vertical recovery system that generates more scraps reduces the productivity of the equipment, causing additional trouble and expense. Therefore, it is undoubtedly important to adopt a pellet recycling system that can be operated independently.

● Fully automatic production line, including paper core automatic machine and film roll automatic processing. The system has an automatic paper core feeding system. It can not only pass the new paper core into the winding shaft of the winder and reach the servo position. It is also possible to automatically roll the film roll with different weights and widths after winding, and even roll the film roll into the designated tray to mark, weigh, and package the film roll for further processing. This system can save labor and logistics costs, and more importantly, it completely separates the workers from the winding station, thus greatly improving the production safety and reliability of high-frequency roll change.

Attached :
How to reduce the production cost of stretch film The various cost factors for the production of stretch film include: 83% of raw materials; 6% of equipment; 3% of paper core and other accessories; 4% of energy consumption; , Marketing accounted for 4%. It can be seen that raw materials have become the primary factor influencing the production cost of stretch film. Therefore, reducing the amount of raw materials and improving process recipes have become the main methods to reduce the production cost of stretch film, the specific methods are as follows:

● Reduce film thickness. From 1975 to 2003, the average thickness of stretch-wound films has been reduced from 30 μm to 20 μm, while the stretch rate has increased from 50% to 300%. This is due to the development of new materials, such as metallocene materials, which provide higher tensile strength and elongation.

● Adopt new raw materials and process recipes. Recently, raw material suppliers provided another opportunity for processors. This means that the slip layer and the adhesive layer are made of the same raw material as the core layer, but a small proportion of the additive masterbatch (usually 10% to 30% of the layer) is added to the cement layer. Similarly, a certain proportion of additive masterbatch (up to 50% of this layer) is also added to the slip layer. At this point, the same large material station can be used to store and optimize the raw materials, and the additive masterbatch can be directly stored in the original small package. Therefore, the processing companies can reduce the diversity of raw materials by their larger orders of single raw materials, and thus get better prices and business conditions.

Although the impact of production equipment is only 6%, its reliability and quality are also very important factors. Because any loss of raw materials due to poor performance of the production line and equipment failure will immediately have a large and direct negative impact on the overall project yield. Considering that even if we increase the investment of equipment by 10% to select better equipment, the cost ratio will only increase from 6% to 6.6%. Therefore, choosing a more reliable and higher quality production line is also a key factor in reducing the production cost of stretch film.