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. 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. This allows companies to either make or buy their own preforms. Difference between extrusion blow molding and injection. Mar 25, 2016 in extrusion blow moulding ebm, plastic is melted and extruded into a hollow tube a parison. After a set time the injection moulds and core pins part and the preform held in a neck carrier. Injection stretch blow molding is a significant variation of this 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 issues for quality control and troubleshooting. Stretch blow molding machine stretch blow moulding. Blow molding and reheat in guelph, on, is part of the twostage process of making bottles from pet or other resins. In this simulation, owing to the symmetry of bottle geometry, the parts are considered as an axisymmetric model. 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. Extrusion blow molding process is slightly different than injection blow molding process. Simulation of the injection stretch blow molding process.
Us20020166833a1 process for making labeled containers. The molecule crosses create a higher quality plastic by increasing barrier strength. After the plastic has cooled sufficiently, the mold is opened and the part is ejected. In this paper, the analysis of the stretchblow moulding sbm process of polyethylene terephthalate pet bottles is studied by the finite element method fem. It is also used for forming glass bottles or other hollow shapes in general, there are three main types of blow molding. Stretch blow molding, third edition, provides the latest on the blow molding process used to produce bottles of the strength required for carbonated drinks. Stretch blow molding is the common method for producing pet bottles. 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.
Troubleshooting tips for injection blow molding used. In extrusion blow moulding ebm, plastic is melted and extruded into a hollow tube a parison. A typical extrusion blow molding process is shown in fig. Method for the evaluation of stretch blow molding simulations. The process is ideal for both narrow and widemouthed containers and produces them fully finished with no flash. Method to evaluate biaxial stretch ratios in stretch blow molding. Lomont molding provides fully customized blow molding services for your project needs. This parison is then captured by closing it into a cooled metal mold. What follows is an explanation of the extrusion blow molding process and how it differs from injection molding. Injection blow moulding is used for the production of hollow objects in large quantities. Troubleshooting guide for blow molding problem possible causes possible solutions 1.
Blow molding explained manufacturing solutions group. The preform then undergoes the stretch and blow process. 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. Stretch blow molding can be a 1step or 2step process depending on the requirements of the package. This process of has been around since the 1970s and stretch blow molding is used widely to package detergent and soda bottles.
As pressure starts to build within the preform, there is very little initial expansion figure 2a. This is a troubleshooting guide that should be in every operators toolbox or on hisher smartphone or tablet. Sfl stretchblow molding equipment is in operation at sipa customers all around the world. Stretch blow molding this process is a bit more complex than the others. The preform then undergoes the stretchandblow process. 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. The rapid guide to perfect pet bottles blow molding. The main applications are bottles, jars and other containers. The plastic is melted and then injected into a mould to form a preform. Injection blow moulding british plastics federation. Pdf numerical study of stretchblow molding of pet bottles. 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. The parison is a tubelike piece of plastic with a hole in one end through which compressed air can pass.
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. 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 this process, the polymer is plasticized in a standard extruder and screw assembly. 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. 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. How does injection stretch blow moulding process work.
Solve four common problems in pet stretchblow molding. As neck finishes become smaller, as is often the case for custom containers, stretch rods have to be smaller too. Biaxial orientation is gained through the supplemental use of a. Mei luo laboratoire modelisation et simulation multi echelle, msme umr 8208 cnrs, universite paris. The parison consists of a fully formed bottlejar neck with a thick tube of polymer attached, which will form the body of the bottle.
Stretch blow molding is the blow molding process used to produce bottles of the strength required for carbonated drinks. The singlestage process is usually done using one machine, where the twostage process uses preforms that have already been made and cooled. Injection stretch blow moulding british plastics federation. Pet stretch blow molding handbook of troubleshooting. These tips are separated for both single and twostage stretch blow molding. This model is capable to offer a helpful knowledge in design of optimum.
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. 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. All of which utilize elements of either extrusion or injection, or both. In the stretch blow molding process, the preform is placed inside the blow mold and preblow low pressure air is introduced. The injection blow moulding process produces bottles of superior visual and dimensional quality compared to extrusion blow moulding. It was concluded that the proposed model is applicable for simulating the stretch blow molding process of pet bottles. 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. Injection stretch blow moulding is the process of manufacturing high quality and very high clarity bottles. The perform is typically preheated then stretched in the axial direction and blown into its final shape by a stretch blow molding machine. All of the processes share distinct production stages. Dec 06, 2011 stretch blow molding is the blow molding process used to produce bottles of the strength required for carbonated drinks. Plastic blow molding fundamental manufacturing processes study guide, dv03pub21 1. On 125 pages 31 common defects of pet bottles are analyzed and tips given to solve them.
This process is used primarily with polyethylene terephthalate pet. The process begins with an injection molded perform. Pdf parameter study of stretchblow moulding process of. The preform is then pre heated before being held inside two halves of a mould.
As that distance increases, the preform may slip to one side. 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. Phd has the actuators of choice to keep your blow molding lines running while increasing productivity and reducing downtime and scrap. Singlestage injectionstretchblow molding isbm machines. Sfl stretch blow molding equipment is in operation at sipa customers all around the world.
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. Hyperelastic model for polyethylene terephthalate behavior yun. It uses small plastic resins that are first stretched vertically and then stretched horizontally to give its molecules a cross shape. Read this guide to understand all about the technology, how it differs from injection molding and the companies that offer blow molding services.
In the ibm process, the polymer is injection molded onto a core pin. Stretch blow molding is the common method for producing soda bottles. 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. 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. How extrusion blow molding differs from injection molding. 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. The 2step process, similar to that of injection blow molding, begins with an injection molded perform. The stretch blow molding process is usually used for producing pet bottles for juices, water, soda, and several other products. In early approaches the material is regarded as purely hyperelastic 15, since pet and other thermoplastics show a rubberlike behavior. 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.
Injection stretch blow moulding is used for the production of high quality containers. Difference between extrusion blow molding and injection blow. It is used to provide optimum optical and barrier properties, which are obtained through biaxial orientation of the polymer chains. Method to evaluate biaxial stretch ratios in stretch blow. Injection blow molding an overview sciencedirect topics. Blow molding pgoduces bia ial orient ati o n greatly figure 46 twostage reheat 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. Biaxial orientation provides enhanced physical properties, clarity, and gas barrier properties, which are all important in products such as bottles for carbonated beverages. Injection blow molding blow molding blow molding process. Injection stretch blowmoulding moulding process spectra. Twostage stretch blow molding is the same as singlestage, except the preforms are already made.