Troubleshooting the extrusion process hanser publications. If melt fracture remained after the first 60 minutes of film extrusion, the fx 9614 level was increased to. Process parameters blown film properties handbook of industrial polyethylene and technology. In experimental study, nonisothermal experiments were conducted using lowdensity polyethylene. Blown film extrusion view abstracts add to favorites email download citations supplemental material download full text pdf select all. Dy namic modeling enables the examination of strategies for process startup, for handling process upsets, and for process control. The degree of draw and orientation is significantly lower in the cast film process than in the blown film process. Crawford, butterworthheinemann blown film process blown, or tubular, film extrusion is one of the major processes used for manufacturing. Labtech blown film attachment attached to a 25 mm singlescrew extruder lf400. Animation of extrusion of ldpe film and shrinking on a 6 x pet bottles and closed cycle at the end. Gels causess possible solutions dirty air ring cont. Definitive guide to manufacturing, properties, processing, applications and markets. The use of degassing or vented extruders used for the extrusion of ps and pmma is possible, but the following is recommended.
Decrease output rate gradually to decrease acceleration rate of minor layer slower screw rotation speed. This book explains certain effects in the blown film process so readers are better able to troubleshoot and improve their operations. 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. C increments and wait 15 to 20 minutes for process to stabilize.
Yet avenues of improvement are open for even the most overextended entrepreneur. Selecting the proper polyamide for multilayer food. 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. Modern plastic handbook, 2000, edited by charles a harper, mcgraw hill. The blown film extrusion process is illustrated in figure 2. There are two main categories of interaction between ppa and. Strategies to avoid interfacial instability in multilayer. 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. Blown film as a process is covered in more detail in part 7, extrusion processes. The process of producing film by extrud ing molten resin. The majority of polymer films are manufactured by film blowing blown film extrusion. 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. If you want the best blown film quality with maximum output rates and optimum material efficiency, the varex ii is the machine of choice.
This allows for higher production line speeds resulting in higher production rates with superior optical properties of the product. Features of the labtech blown film attachment lf250 and lf400. 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. 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. 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. Pdf blown film extrusion an introduction nonoy aguilar. Without her help, it would have been impossible to simulate the blown film processing. Blown film cast film lamination co extrusion 2002 alpine 7layer, 80 blown film extrusion line, 2. Yan ding, my supervisor in the school of mathematics and geospatial sciences. Integrity because no successful bond can be formed without trust, we are fair and honest in all our relation. It has been shown that antiblock additives in blown film applications can adversely affect ppa performance by interacting with the ppa 25.
In all cases, the plastic must be converted from its raw material statepellet or powderand melted and pressurized via the extrusion process. 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 bubble is then collapsed and used as a layflat film or can be made into bags. The second edition of extrusion is designed to aid operators, engineers, and managers in extrusion processing in quickly answering practical daytoday questions.
The bubble is blown vertically, creating a long bubble like a party balloon. 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. This is a small line compared to the larger production facility shown with the large tower and windup from macchi 2 in figure 31. 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. Each evaluation began with an fx 9614 level of 100 ppm. Table 1 presents a very useful polyethylene film processing troubleshooting guide. Schematic of blown jzh extrusion a circumferential tension on the bubbletube.
Blown film processes and troubleshootingand troubleshooting the ultimate quality control tool presented by. Here the system of pdes for the dynamic modeling of blown film extrusion is solved using numerical methodoflines nmol 2. And some of the most effective modifications cost little more than a phone call or a small change in procedures. This is done either in line with the blown film process or at a later stage. Paul waller president plastics touchpoint group, inc. 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. The blown film extrusion process can produce magnificent arrays of products however. The effects of antiblocking agents on the performance of.
The polymer processing additive used in part i blown film experiments was dynamar fx 9614. The resulting thin film has a form of a tube, also called a bubble blown film. 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. This creates a bubble in the molten plastic, just like a person blowing a bubble in chewing gum. Our blown film offering is defined by maximum value with a global approach. 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. The blown film process consists of injecting molten plastic into a blow film machine and blowing air through the molten plastic. A single screw extruder is used to melt the polymer and pump it into a. Conditions reduce extensional viscosity and stress at layer interface by increasing melt temperature of minor layer. Troubleshooting the extrusion process a systematic approach to solving plastic extrusion problems 2nd edition maria del pilar noriega e. At the same time, current practices and equipment are emphasized to keep readers uptodate with the most productive and efficient technology. Kirk cantor blown film extrusion an introduction hanser publishers, munich hanser gardner publications, cincinnati the author. Enabling our partners throughout the blown film value chain to.
In the event of excessive slip, treat only side of film which contacts rollers. Unlike the blown film process, the cooling of the film with cast extrusion is highly efficient. She helped me to understand the numerical techniques of the blown film modelling and simulation. The blown film extrusion process was investigated both experimentally and theoretically. Fundamentals of cast film extrusion technologymacro. The vent opening should be plugged or sealed to prevent escaping of the gas generated by the foaming agent. Blown film extrusion is a technology that is the most common method to make plastic w films, especially for the packaging industry. Publishers pdf, also known as version of record includes final page, issue and.
The re sulting biaxial stress can further induce crystalliza tion, an action termed flowinduced crystallization. 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. 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 ppa was added to the lldpe as a 3% concentrate in a 2.