Thermosets and thermoplastics are the two most common types of plastic used in blow molding. The main difference between them is the way they process heat: under high temperatures, thermoplastics will melt, whereas thermosets will solidify.
Characteristics of Plastics
This is because under heat, a thermosetting polymer cannot be weakened; its three-dimensional chain will cross-link and strengthen irreversibly. On the other hand, thermoplastic polymers hold the shape of a one-dimensional string of monomers whose bonds weaken rapidly under heat, thus causing the plastic to melt and allowing it to be re-shaped. When cooled, the thermoplastic bonds will strengthen and the plastic will re-solidify.
Needless to say, many molding processes require the use of thermoplastics or thermosets, including extrusion blow molding.
Extrusion Blow Molding
Extrusion molding is an industrial process that melts raw thermoplastics in the form of granules. The plastic is fed into a machine through a revolving chamber, which will melt it and force it through something called a “die,” which is similar to a mold in that it provides shape, but it does so by cutting materials as they are forced through. The finished products are often long and rough shapes such as rods, sheet metal, or pipes.
The Process of Molding Plastic
Blow molding is the process of molding plastic into a hollow shape. It can be done through either an Extrusion method. In the Extrusion method, the melted plastic is forced through a die to be shaped like a tube. The product’s mold then entraps the tube. From the top, a blow pin is inserted through the tube and air pressure inflates the plastic into the hollow shape of the mold it is trapped in. In the Injection method, the process is very similar except a die is not used to form the tube; the tube is formed when melted plastic is directly injected into a mold made specifically for it.
Ejecting a molten liquid plastic material into a preformed mold creates extrusion blow molded plastics. The two halves of the mold are pressed together and air pressure is used to blow in the liquid plastic until it fully fills the preformed cavity conforming to the mold’s shape. When the molding process in completed, the molded plastic component is emptied from the mold and trimmed of any over molded plastic fragments that are not part of the intended finished piece.
The component is allowed to cool until totally solid and the plastic fully congeals and any additional finishing work is then done to the piece. Some molds have multi-injectors and several plastic components can be fabricated at the same time. Multi-molding allows for a more rapid fabrication process.
Advantages of Extrusion Blow Molding for Blow Mold Plastics
The extrusion blow molding fabrication process is appropriate for creating parts that do not have to be highly precise, can have only one thickness, and do not need to have precise exterior finishes. Extrusion blow molding may be a superior and more inexpensive process for you, since injection molding and injection blow molding can be a more costly process due to higher cost of the injector apparatus. The Western Case team can assist you in figuring out which particular molding process suits your product fabrication needs so that you can plan accordingly.
We have fabricated and helped launch successful projects for all of the world’s top automotive companies. We are proud to be a supplier and we seek to provide our utmost in the area of quality assurance, precision engineering, and project management support.
Western Case’s time honored experience extends to the following manufacturing areas:
Automotive components for exteriors
- Paneling and Railing
- Bumper Support
- Mud Guards
- Door Locking Systems
Automotive Molded Systems – Interior Components
- Garnish Pillars
- Storage Systems
Interior Wrapping for Automotive applications
- Console Lids
- Shifter Knobs
- Steering Wheels
Under the Hood plastic components
- Fan Shroud
- Cooling Systems
- Fuel Tank Systems
- Electrical Covers
Decorative Automotive plastic components
- Interior /Exterior Trim
Extrusion blow molding is a highly versatile manufacturing process and it is used in many different industries. It allows you to create a product that has a uniform cross section. It seems unlikely that the same process that gives us candy canes and drinking straws also forms PVC pipe and automotive hoses, but it does. Using different materials, extrusion blow molding can produce an astonishing variety of products.
How Extrusion Blow Molding Works
Plastic extrusion molding uses thermoplastic pellets. The pellets are placed in a hopper and moved along to the heated barrel where they are melted. The melted thermoplastic is then forced through the die, which is shaped like the intended finished product. The result of this process is a continuous, long part that can then be cut into any size desired.
Advantages of Extrusion Blow Molding Plastic Products
The advantages of extrusion blow molding plastic products are far too numerous to mention, but among the most important is the low production cost. The cost is so low because the initial setup takes very little time and is very inexpensive. In addition to this, the process itself is amazingly efficient. On top of an already minimal production cost, there is very little waste produced during manufacturing, which brings the cost down even more.
The lack of excessive waste is due to the fact that the nature of thermoplastics allows any waste that accumulates to simply be melted down and used again. Not only does less waste mean lower material costs, but it puts less stress on the environment as well; both in landfill space and the raw materials used to produce the thermoplastics.
Western Case Produces Quality Blow Molded Plastics
Blow molded plastics have vastly changed the face of the shipping industry worldwide. Western Case strives to keep abreast of the latest technology to continue producing the quality custom blow molded plastics that our customers have come to expect.
Contact us at 877-593-2182 or email at firstname.lastname@example.org for a quote on your project.
Extrusion plastic blow molding works by having molten plastic poured into a water-cooled mold. As soon as the molds are closed, air is run into the container, blowing the plastic into the desired shape of the mold. The mold is removed once the plastic has cooled, leaving the desired product.
Advantages to Extrusion Blow Molded Plastics
Although extrusion blow molding is simplistic, it still has major advantages. These benefits include a larger variation of container/neck shapes and sizes. Even handle-ware can be made.
Extrusion blow molds are far less expensive and can be produced significantly quicker. With these types of molds, they altogether have a higher rate of production, low cost of tools, and a variation of machines.
Western Case’s manufacturing facility for plastic blow molding has the ability to turnaround small and large orders for production. Our machinery makes for low cost production and efficiency.
Process of Extrusion Blow Molding
The plastic is first melted down into a liquid state. Once this is done, it is then placed together between two molds. The plastic is then filled with air to make it inflate until it reaches the molds. After it cools, a new mold has been made.
Contact Plastic Blow Molding Company, Western Case
Western Case strives to produce the highest quality plastic blow molding for our customers. With our commitment to high quality and attention to inspecting products, we ensure we meet the requirements needed for your products. Contact Western Case at 877-593-2182 of email us at email@example.com to get a quote.