Blown film as a process is covered in more detail in part 7, extrusion processes. If kept as layflat, the tube of film is made into bags by sealing across the width of film and cutting or perforating to make each bag. This allows for higher production line speeds resulting in higher production rates with superior optical properties of the product. Definitive guide to manufacturing, properties, processing, applications and markets. Integrity because no successful bond can be formed without trust, we are fair and honest in all our relation. Blown film processes and troubleshootingand troubleshooting the ultimate quality control tool presented by. At the same time, current practices and equipment are emphasized to keep readers uptodate with the most productive and efficient technology. Before performing any procedure, it is the machine operators responsibility to be aware of their companys safety policy, to wear the appropriate personal protective equipment, and to make sure that only authorized personnel are in the area.
She helped me to understand the numerical techniques of the blown film modelling and simulation. Gels causess possible solutions dirty air ring cont. The use of degassing or vented extruders used for the extrusion of ps and pmma is possible, but the following is recommended. Blown film extrusion is a technology that is the most common method to make plastic w films, especially for the packaging industry.
The re sulting biaxial stress can further induce crystalliza tion, an action termed flowinduced crystallization. The ppa was added to the lldpe as a 3% concentrate in a 2. Animation of extrusion of ldpe film and shrinking on a 6 x pet bottles and closed cycle at the end. In a blown film process for manufacturing plastic film bags, the shape of the film bag being formed is dynamically controlled by sensors provided at specific locations. In india, extrusion based methods account for 75 % of the total plastic processed, out of which 27 % share is of blown films mutha et al. In all cases, the plastic must be converted from its raw material statepellet or powderand melted and pressurized via the extrusion process.
Modern plastic handbook, 2000, edited by charles a harper, mcgraw hill. Blown film extrusion view abstracts add to favorites email download citations supplemental material download full text pdf select all. Blown film cast film lamination co extrusion 2002 alpine 7layer, 80 blown film extrusion line, 2. Process parameters blown film properties handbook of industrial polyethylene and technology. Troubleshooting the extrusion process a systematic approach to solving plastic extrusion problems 2nd edition maria del pilar noriega e. The bubble is blown vertically, creating a long bubble like a party balloon.
Labtech blown film attachment attached to a 25 mm singlescrew extruder lf400. Decrease output rate gradually to decrease acceleration rate of minor layer slower screw rotation speed. If you want the best blown film quality with maximum output rates and optimum material efficiency, the varex ii is the machine of choice. The markets served by blown film extrusion process include industrial films and bags, agricultural and construction films, barrier films stretch films, pvc cling films, laminating films, can liners, and high barrier small tube systems. The degree of draw and orientation is significantly lower in the cast film process than in the blown film process. A single screw extruder is used to melt the polymer and pump it into a. Unlike the blown film process, the cooling of the film with cast extrusion is highly efficient. Dy namic modeling enables the examination of strategies for process startup, for handling process upsets, and for process control.
C increments and wait 15 to 20 minutes for process to stabilize. Features of the labtech blown film attachment lf250 and lf400. Each evaluation began with an fx 9614 level of 100 ppm. For example, this process can be used to improve the characteristics of paper by coating it with polyethylene to make it more resistant to water. Strategies to avoid interfacial instability in multilayer. The effects of antiblocking agents on the performance of. Schematic of blown jzh extrusion a circumferential tension on the bubbletube. There are two main categories of interaction between ppa and.
At these locations, any deviation of the bag shape from the ideal shape will result in significant differences in quality of the produced film bag, or may result in a break of the film bag. The majority of polymer films are manufactured by film blowing blown film extrusion. Our blown film offering is defined by maximum value with a global approach. The blown film process consists of injecting molten plastic into a blow film machine and blowing air through the molten plastic. Yan ding, my supervisor in the school of mathematics and geospatial sciences. Paul waller president plastics touchpoint group, inc. Here the system of pdes for the dynamic modeling of blown film extrusion is solved using numerical methodoflines nmol 2. Extrusion coating is using a blown or cast film process to coat an additional layer onto an existing roll stock of paper, foil or film. Chris rauwendaal isbns 9781569904701 1569904707 hanser hanser publishers, munich hanser publications, cincinnati sample chapter 1.
The blown film extrusion process was investigated both experimentally and theoretically. Publishers pdf, also known as version of record includes final page, issue and. The second edition of extrusion is designed to aid operators, engineers, and managers in extrusion processing in quickly answering practical daytoday questions. The blown film extrusion process can produce magnificent arrays of products however. Pdf blown film extrusion an introduction nonoy aguilar. Comprehensive process control large diameter, high speed winders a team approach to implementing blown high density film technology before and during installation, gloucester specialists not only apply their extensive, highly practical knowledge of blown hd film to your production line, but also teach it to you and your staff. Without her help, it would have been impossible to simulate the blown film processing. The development of the varex ii was driven by productivity, flexibility, ergonomics and sustainability. Polyethylene film processing guide quality, value and performance our guiding principles everything we do at formosa is measured against the following guiding principles. The polymer processing additive used in part i blown film experiments was dynamar fx 9614. This creates a bubble in the molten plastic, just like a person blowing a bubble in chewing gum. This is a small line compared to the larger production facility shown with the large tower and windup from macchi 2 in figure 31.
In experimental study, nonisothermal experiments were conducted using lowdensity polyethylene. Kirk cantor blown film extrusion an introduction hanser publishers, munich hanser gardner publications, cincinnati the author. From hardware and materials through processing and properties, this book presents a broad coverage of blown film extrusion and ensures a useful balance of theory and practice. The resulting thin film has a form of a tube, also called a bubble blown film. Table 1 presents a very useful polyethylene film processing troubleshooting guide. The first part of the book provides the fundamental principles, for operators and engineers, of polymeric materials extrusion processing in single and twin screw extruders. Blown film processors, many of them small enterprises with a single plant or a single costly line, may have limited resources, in both capital and manpower, to devote to optimizing their productivity. Crawford, butterworthheinemann blown film process blown, or tubular, film extrusion is one of the major processes used for manufacturing. The vent opening should be plugged or sealed to prevent escaping of the gas generated by the foaming agent. The process of producing film by extrud ing molten resin.
Fundamentals of cast film extrusion technologymacro. In the event of excessive slip, treat only side of film which contacts rollers. This bubble is then collapsed and used as a layflat film or can be made into bags. It has been shown that antiblock additives in blown film applications can adversely affect ppa performance by interacting with the ppa 25. A new video produced by borealis and gea, a leading global supplier of process technology for food, puts the spotlight on an innovative flexible packaging solution which both safeguards food freshness and improves the energy efficiency and sustainability of production processes. This is done either in line with the blown film process or at a later stage. Troubleshooting the extrusion process hanser publications. Enabling our partners throughout the blown film value chain to. We deliver more throughout the blown film process with highperformance extruders and equipment for processing eva, ldpe and lldpe films, as well as proven extrusion technology for soe slitonedge, bur blowup ratio and ddr drawdown ratio technology.
And some of the most effective modifications cost little more than a phone call or a small change in procedures. The blown film process is a continuous process, as such the machinery has to be designed to cope with both the high speeds involved and be able to operate on a 24 hour basis. Selecting the proper polyamide for multilayer food. Yet avenues of improvement are open for even the most overextended entrepreneur. Conditions reduce extensional viscosity and stress at layer interface by increasing melt temperature of minor layer. If melt fracture remained after the first 60 minutes of film extrusion, the fx 9614 level was increased to. The blown film extrusion process is illustrated in figure 2.