Blow Molding Machines
Blow molding machines make the plastic bottles that millions of people drink from each day. This technology is used in other plastic products as well. It is one of the most interesting and useful inventions in modern manufacturing.
This process is called extrusion blow molding. The melted plastic is fed through a nozzle to a parison, which is clamped and inflated by air.
1. Extrusion Process
The process used to make many of the bottles and jars we use every day is known as extrusion blow molding. It begins with plastic pellets that enter the extruder where frictional and shear heat melt them. The molten material is then shaped into a parison, which is then captured within the mold and inflated to form a finished part.
The extrusion system may work with a reciprocating screw or an accumulator head. The former gathers melted plastic resin, and blow molding machine once enough has accumulated a rod pushes it into the die to create the parison. This reduces the weight of the molten parison, which allows for precise control of wall thickness.
Once the pliable parison is formed it is suspended between two clamping mold halves. A pin, called a blow pin, is then inserted into the center of the parison and pressurized air is blown in, which conforms the molded plastic to the mold.
The mold is then closed, which is important to prevent the product from being ejected during the cooling process. Once the plastic has sufficiently cooled and solidified, it is released from the mold. The mold can then be reopened for the next cycle. This is a continuous process, and there are many variations in the equipment used to produce this type of product including equipment made to extrude multiple parisons simultaneously, equipment that utilizes injection blow molding to create a preform which is then transferred to an extrusion machine for stretching and blowing.
2. Molding Process
Blow molding is a manufacturing process that allows for the creation of hollow plastic products. It has its roots in glass blowing, and it is now one of the most popular methods for creating bottles and jars. During the process, soft molten plastic is inflated like a balloon by compressed air in order to take the shape of the mold. The amount of air pressure used and the plastic type itself determines how thick the final product will be.
The melted plastic is fed through an extruder and then into a hot-runner manifold. From there, it’s injected into a preform mold that has the shape of the product’s body. A core pin then forms the internal structure of the preform. Once the preform has been formed, it’s then clamped around a blowing die. The pressurized air is then blown into the preform, inflating it and filling the space within the product mold.
This air pressure creates the desired shape of the product, allowing it to take on the mold’s shape as it cools and hardens. Depending on the type of plastic being used and its intended application, there are different methods for doing this. These include continuous, intermittent and single-stage blow molding. Each method has its own advantages and disadvantages.
3. Finishing Process
Blow molding is a production process for crafting hollow plastic items. Like glass blowing before it, the process involves heating a polymer until it becomes malleable and then moulding it to form a thick tube that takes on the shape of a bottle or other item being produced. This initial shape is known as a parison and it serves as the foundation that will be modified in later stages to create the final product design.
Once the parison is formed, it’s transported through a metal mold that’s closed around it. A heated balloon of compressed air is then forced through the hole at the end of the parison to inflate it and mould it to the desired shape of the final product. Once the inflated parison cools, the mold is opened and the finished product is ejected from the machine.
The final product is then ready to be inspected, labelled, and shipped. Though the basic blow molding process is fairly simple, manufacturing plants often employ additional processes based on the design and intended application of the final product. Constraints in material selection can also limit blow molding capabilities, particularly when working with certain polymers that aren’t well-suited to the process. This can limit design flexibility and necessitate a shift to alternative production techniques. Nonetheless, this remains a highly cost-effective and efficient production method for crafting a wide range of plastic items.
4. Packaging
Blow molding is a versatile manufacturing process capable of producing a blow molding machine factory variety of hollow plastic products. It’s used to produce everything from small custom bottles and containers for consumer products like water or shampoo, to larger industrial jobs like plastic storage tanks or big plastic drums. Today’s blow molding machines are designed to accommodate a wide range of raw materials, including lightweight plastics that can decrease overall production costs without compromising product quality.
The basic principle of the blow molding process is to heat and then inflate a molded piece of plastic with compressed air. This inflated plastic takes the shape of the mold and is then clamped in place until it cools. The resulting hollow plastic product is then ready to be finished and shipped.
Our rotary blow molders are capable of creating a wide variety of standard and complex containers, from three to ten liters. The machine can also be configured for stretch blowing to handle thick-walled preforms for five-to-ten liter bottles, with high preform stretch ratios to support a wide range of bottle shapes.
Rotary wheel blow molding machines utilize multiple molds located on the periphery of a rotating wheel allowing for continuous production and high output rates. Our BM 2001 model, for example, is designed to manufacture 1000L IBCs and L-Ring drums as well as other large plastic packaging like water tanks, and septic tank liners. This enables us to provide you with a full solution for all of your blow-molded container needs.
