It uses small plastic resins that are first stretched vertically and then stretched horizontally to give its molecules a cross shape. The mechanical behavior of polyethylene terephthalate pet under the severe loading conditions of the injection stretch blow molding process is strongly dependent on strain rate, strain, and temperature. Pdf parameter study of stretchblow moulding process of. A new process for making a labeled container using a stretch blow molding process wherein a label sleeve is positioned over at least a portion of the exterior surface of a preform to produce a sleeved preform and the sleeved preform is stretch blow molded to. Difference between extrusion blow molding and injection. Injection blow moulding is used for the production of hollow objects in large quantities. If you blow air into a plastic tube that is closed on all sides except the point at which the air enters, the tube will. It is used to provide optimum optical and barrier properties, which are obtained through biaxial orientation of the polymer chains. Us20020166833a1 process for making labeled containers using. Method for the evaluation of stretch blow molding simulations. The process begins with an injection molded perform. Injection blow molding blow molding blow molding process.
This process of has been around since the 1970s and stretch blow molding is used widely to package detergent and soda bottles. Pdf numerical study of stretchblow molding of pet bottles. It is also used for forming glass bottles or other hollow shapes in general, there are three main types of blow molding. Method to evaluate biaxial stretch ratios in stretch blow molding. After each defect an explanation gives more background into why. A lot of research has been done so far to capture the complex material behavior during sbm or related processes like thermoforming and extrusion blow molding. Hyperelastic model for polyethylene terephthalate behavior yun. Blow molding pgoduces bia ial orient ati o n greatly figure 46 twostage reheat blow molding. Blow molding process extrusion injection stretch intermittent continuous reciprocating screw accumulator head side ram accumulator shuttle wheel special multilayer biaxial orientation 1 step 2 step dip displacement neck ring drape for small, high production clear parts, injection blow molding would be the process of choice. In this paper, the analysis of the stretchblow moulding sbm process of polyethylene terephthalate pet bottles is studied by the finite element method fem.
The process is ideal for both narrow and widemouthed containers and produces them fully finished with no flash. What follows is an explanation of the extrusion blow molding process and how it differs from injection molding. Mar 25, 2016 in extrusion blow moulding ebm, plastic is melted and extruded into a hollow tube a parison. This process is used primarily with polyethylene terephthalate pet. The perform is typically preheated then stretched in the axial direction and blown into its final shape by a stretch blow molding machine. This parison is then captured by closing it into a cooled metal mold. Injection stretch blowmoulding moulding process spectra. Injection blow molding ibm is similar to extrusion blow molding, except that the parison is formed by an injection molding process around a core rod or metal shank as shown in position 1 in the schematic in fig. Mei luo laboratoire modelisation et simulation multi echelle, msme umr 8208 cnrs, universite paris. In early approaches the material is regarded as purely hyperelastic 15, since pet and other thermoplastics show a rubberlike behavior.
In this handbook, ottmar brandau introduces the technology of stretch blow molding, explores practical aspects of designing and running a production line and looks at practical issues for quality control and troubleshooting. Sfl stretch blow molding equipment is in operation at sipa customers all around the world. It was concluded that the proposed model is applicable for simulating the stretch blow molding process of pet bottles. In extrusion blow moulding ebm, plastic is melted and extruded into a hollow tube a parison. An aneurysm starts to form in the middle of the preform figure 2b and continues to get larger until a prebottle is. Implement a quality assurance syste stearate is identifies any trends and allows for develop and publish the quality standards change to become apparent, record changes in continued on page 2 introduction injection blow molding incorporates particular characteristics and advantages over other. This model is capable to offer a helpful knowledge in design of optimum. The parison consists of a fully formed bottlejar neck with a thick tube of polymer attached, which will form the body of the bottle. In the stretch blow molding process, the preform is placed inside the blow mold and preblow low pressure air is introduced. Blow molding moulding is a specific manufacturing process by which hollow plastic parts are formed and can be joined together. How does injection stretch blow moulding process work. Singlestage injectionstretchblow molding isbm machines. Air is then blown into the parison, inflating it into the shape of the hollow bottle, container, or part. Phd has the actuators of choice to keep your blow molding lines running while increasing productivity and reducing downtime and scrap.
Injection stretch blow moulding british plastics federation. Troubleshooting guide for blow molding problem possible causes possible solutions 1. Sfl stretchblow molding equipment is in operation at sipa customers all around the world. The molecule crosses create a higher quality plastic by increasing barrier strength. Injection blow molding an overview sciencedirect topics. Injection stretch blow moulding is the process of manufacturing high quality and very high clarity bottles. As neck finishes become smaller, as is often the case for custom containers, stretch rods have to be smaller too. Injection stretch blow moulding is used for the production of high quality containers. The preform is then pre heated before being held inside two halves of a mould.
In this process, the polymer is plasticized in a standard extruder and screw assembly. Difference between extrusion blow molding and injection blow. The blow molding process begins with melting down the plastic and forming it into a parison or in the case of injection and injection stretch blow moulding isb a preform. In general terms, blow molding is the process in which a hot parison or preform is inflated within a closed mold to impart the shape of the mold cavity. Dec 06, 2011 stretch blow molding is the blow molding process used to produce bottles of the strength required for carbonated drinks. Vents neck ring pinchoff mold body bottom insert pinchoff tail grabber slots for automatic trimmer a blow molding mold for a container with a handle. Extrusion blow molding ebm is a manufacturing process whereby plastic is melted and extruded that is, expelled to form a shape into a hollow tube. The preform then undergoes the stretchandblow process. Read this guide to understand all about the technology, how it differs from injection molding and the companies that offer blow molding services. Stretch blow molding can be a 1step or 2step process depending on the requirements of the package. After the plastic has cooled sufficiently, the mold is opened and the part is ejected. Twostage stretch blow molding is the same as singlestage, except the preforms are already made. All of the processes share distinct production stages. Stretch blow molding is the common method for producing soda bottles.
Processors appreciate it for its wide processing window, its ease of use, its production stability, its energy efficiency, its low cost of maintenance, and its ability to produce a broad range of container types, including oval shapes and hotfillables. The injection blow moulding process produces bottles of superior visual and dimensional quality compared to extrusion blow moulding. The preform then undergoes the stretch and blow process. Troubleshooting tips for injection blow molding used. Injection blow molding is the process whereby the plastic preform is injection molded and the preform travels on the core rod to the blow mold station, where blow air enters through the core rod and lifts the hot preform material off the core rod and forms it by air pressure to the design of the female blow mold. Simulation of the injection stretch blow molding process. This allows companies to either make or buy their own preforms. Molten polymer flows into the injection cavity via the hot runner block, to produce the desired shape of the preform with a mandrel the core pin producing the inner diameter and the injection cavity the outer. Introduction understanding the mechanical behavior of pet and resulting implications in the design of packaging containers has advanced significantly in the past four decades 1, 2, 3, 4. Stretch blow molding this process is a bit more complex than the others. Extrusion blow molding process is slightly different than injection blow molding process. In this updated handbook, ottmar brandau introduces the technology of stretch blow molding, explores practical aspects of designing and running a production line, and looks at practical. The main applications are bottles, jars and other containers. The singlestage process is usually done using one machine, where the twostage process uses preforms that have already been made and cooled.
Blow molding and reheat in guelph, on, is part of the twostage process of making bottles from pet or other resins. These tips are separated for both single and twostage stretch blow molding. After a set time the injection moulds and core pins part and the preform held in a neck carrier. Us20020166833a1 process for making labeled containers. The plastic is melted and then injected into a mould to form a preform. Stretch blow molding is the common method for producing pet bottles. Stretch blow molding machine stretch blow moulding. Biaxial orientation is gained through the supplemental use of a. Method to evaluate biaxial stretch ratios in stretch blow. In this simulation, owing to the symmetry of bottle geometry, the parts are considered as an axisymmetric model. Solve four common problems in pet stretchblow molding.
As that distance increases, the preform may slip to one side. The twostage process has separate injection for the preforms, and separate blow moulding in which the preform is stretched and blown to its final shape. Blow molding explained manufacturing solutions group. Blow molding design guideline blow molding design guideline 3 radii corners material will freeze when it comes into contact with the mold, causing it to stretch into corners if parison is trapped pinched off at parting line, it must stretch into the cavity preblowing the parison prior to mold closure helps minimize stretch. How extrusion blow molding differs from injection molding. Plastic blow molding fundamental manufacturing processes study guide, dv03pub21 1. As pressure starts to build within the preform, there is very little initial expansion figure 2a.
Stretch blow molding, third edition, provides the latest on the blow molding process used to produce bottles of the strength required for carbonated drinks. When the preform is in the mould it is then inflated using high pressured air while. Parison not being blown defective blow timer, clogged blow lines, or too sharp pinchoffs replace blow timer clean blow lines stone pinchoffs to create more pinch area reset cushion clean tooling 2. Injection blow moulding british plastics federation. Others include injection blow molding, biaxial stretch blow molding, and coextrusion blow molding. Injection blow molding is the process of inflating a hot, hollow, thermoplastic preform or parison inside a closed mold, so its shape conforms to that of the mold cavity. In this updated handbook, ottmar brandau introduces the technology of stretch blow molding, explores practical aspects of designing and running a production line, and looks at practical issues for quality control and troubleshooting. A typical extrusion blow molding process is shown in fig. During the first stage, injection machines produce vial or testtube shaped preforms. Pet stretch blow molding handbook of troubleshooting.
Stretch blow molding is the blow molding process used to produce bottles of the strength required for carbonated drinks. This is a troubleshooting guide that should be in every operators toolbox or on hisher smartphone or tablet. In the ibm process, the polymer is injection molded onto a core pin. Lomont molding provides fully customized blow molding services for your project needs. Blow molding reheat guelph, on apex container tech inc. The 2step process, similar to that of injection blow molding, begins with an injection molded perform. Jan 24, 2015 the twostage process has separate injection for the preforms, and separate blow moulding in which the preform is stretched and blown to its final shape. At this point of the process this material is generally referred to as a parison, which is a round melted mass that will then be molded. On 125 pages 31 common defects of pet bottles are analyzed and tips given to solve them. All of which utilize elements of either extrusion or injection, or both. Injection stretch blow molding is a significant variation of this process. The parison is a tubelike piece of plastic with a hole in one end through which compressed air can pass.
The stretch blow molding process is usually used for producing pet bottles for juices, water, soda, and several other products. The rapid guide to perfect pet bottles blow molding. A new process for making a labeled container using a stretch blow molding process wherein a label sleeve is positioned over at least a portion of the exterior surface of a preform to produce a sleeved preform and the sleeved preform is stretch blow molded to produce a labeled container having a snugfit label. Silgan plastics technologies injection stretch blow molding.