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Tag Archives: blow molding production

The Basics in Blow Molding Production

Plastic makes an appearance in almost everything, from normal keyboards to all the tiny plastic components, showing up in a myriad of different shapes and sizes. How does blow molding production, or plastic production, work?

The Process of Plastic Production

Many of these plastic products begin with a process known as plastic extrusion. Dating back to the late 18th century, the process involves heating small plastic pellets at a high temperature, forcing it into a die for its shape, and allowing it to cool and harden. The use of a heated screw feeder helps force the melted plastic into the die.

After this process is done, many of these forms are reheated again for another process called sheet or film extrusion. The re-melted plastic is then cooled and pressed through calendar rolls to spread and harden, creating plastic sheets.

Benefits of Extrusion Blow Molding

These sheets can be worked yet again in another process called co-extrusion. For this, multiple extruders are melted together and forced into a single die. This allows for the plastic product to have a softer touch, a matted finish, and have gripped surfaces.

The last type of plastic working is thermoforming. This process uses a plastic sheet that is heated until it is soft and forcing it into a mold. Vacuums are sometimes used to force it into the complex forms required.

Since plastics play such a wide range of roles, it is not surprising the amount of processes that occur to mold and shape them. Everything from keyboards to cars, plastic is an important industry.

Overview of Extrusion Blow Molding Process

Blow molding production helps make three-dimensional articles made from thermoplastics materials, such as granules or powders. Two parts on the tool help contain a closed cavity. The powder is softened in a cylinder and eventually extruded into a tube.

The Basics of Using a Parison

The parison is surrounded by the mold, which is closed to seal the lower end of the parison. The wall thickness depends on the size of the parison, along with the mold. Die design is based on factors such as melt flow pattern, band length and backpressure. These features help produce bottles with wall thickness.

The understanding of temperature is important. It is required that you have optimized screw design to handle the specific polymer. The die’s uniform pressure, temperature, and viscosity should not vary.

Backpressure should merge wild lines. You should clamp the two halves around the parison and then cut it as it goes to the blow station.

Expand the parison and then cut it as it goes to the blow station. Expanding the parison into the cavity allows the cooling of mold to take place. Ejection is carried out after the mold has exhausted air.

Disadvantages of Using Molds

However, there are some disadvantages. Wall thickness decreases as the mold diameter increases. This causes thinning to occur. Since the holes cannot be moulded in, that leads to a post-molding operation. Cooling times are longer for injections because the molding is cooled from the exterior. Due to wall thickness, the cycle time may be longer and the molding may be heavier.

The Extrusion Blow Molding Process in Plastic Bottle Production

Blow molded products are all around us. From water bottles to carrying cases for power tools, blow molding is a fast, efficient, and inexpensive way to manufacture many of the things we use every day.

Processes to Plastic Bottle Blow Molding

There are four different blow molding processes used to produce plastic containers and bottles: injection blow molding, stretch blow molding, reheat and blow molding, and extrusion blow molding. Of all the processes, the least complicated is perhaps extrusion blow molding. It is also among the most versatile and cost effective ways to produce a vast array of different products.

Extrusion Blow Molding Production

In extrusion blow molding production, a tube of hot plastic called a parison is extruded into a mold that has been water cooled. The mold is then closed and air is blown into the tube to inflate it to the dimensions of the mold. Once the hot plastic hits the cooled mold, it “freezes” and maintains the shape of the mold.

Extrusion blow molding is generally considered to be the most versatile of all the blow molding processes because it allows for a much wider variety of sizes, shapes, handles, and neck openings. Injection blow molding on the other hand, is suitable only for smaller containers with no handle ware involved. Extrusion blow molding products can be produced at a lesser cost in part because the molds are much less expensive to produce and can be made in a much shorter time span.

Blow Molding Products Produced with the Extrusion Process

Western Case Inc. produces a vast array of extrusion blow molded products, from reservoirs and tanks, to toys and sporting goods. Our manufacturing and engineering teamwork closely with each client to assure that their needs are met and even exceeded. Providing quality blow molded products around the world, pride ourselves on placing customer satisfaction at the top of our list of priorities.

Technology and Materials Used for Blow Mold Plastics and Production

Blow molding uses air pressure to inflate soft plastic into the cavity of a mold. It produces one-piece plastic parts that are hollow with thin walls, like bottles and other containers. These blow mold plastics typically are produced in very large quantities because many are utilized for mass-market consumer beverages.

Blow Molding Technology – Where It Originated

Blow molding technology originated with the glass industry, which competes with the plastics industry in the recyclable and disposable bottle market.

The Steps of Blow Molding Production

Blow molding has two steps.

1. The first step is fabricating a molten plastic tube, known as a parison. This is done either through injection molding or extrusion.

Injection molding uses an injection unit and a clamping unit and can form three-dimensional shapes. Extrusion pushes the material through a two-dimensional opening and through a series of sizes or shapes until it reaches the desired form. It produces linear shapes.

2. The second step in blow molding is inflating the tube until it reaches the desired shape.
Blow molding only is used for thermoplastics.

Materials Used for Blow Mold Plastics

The most commonly used polymer is polyethylene, especially high molecular weight polyethylene (HMWPE) and high density polyethylene (HDPE).

These more expensive materials are more economical than low-density polyethylene, since the stiff container walls can be thinner. Blow moldings also can be made from polyethylene terephthalate, polyvinyl chloride and polypropylene.

Most products from blow molding production are used for disposable containers for liquid consumer goods. Other products include 55-gallon shipping drums for powders and liquids, 2000-gallon storage tanks, automobile gasoline tanks, toys and small boat and sailboard hulls.

How Extrusion Blow Molding Production Works and Materials Used to Create Products

The process of extrusion blow molding is most commonly used in the manufacturing of hollow vessels that can be of nearly any size from small, squeeze bottles such as food coloring comes in, to large septic or water retention tanks.

Materials Used in Blow Molding Manufacturing

There are various materials used for blow molding, but they are limited to thermoplastics.

Polyethylene is the most commonly used of the entire blow molding materials, more specifically HDPE and HMWPE (High Molecular Weight Polyethylene). When compared to the properties seen in low density PE, it is more cost effective to use these higher quality materials.

While the materials may be more costly, the walls of the container can be thinner while still producing a quality end product. Other materials used in blow molding production include PP (polypropylene), PVC (polyvinylchloride), and Polyethylene terephthalate.

High Density Polyethylene

HDPE stands for High Density Polyethylene and its inherent properties make it suitable for a wide variety of applications. It has a high tensile strength, high rigidity, excellent chemical and solvent resistance, and it conforms to the FDA standards for direct contact with food. Each year, over eight million tons of HDPE is used in the manufacturing of such blow molded containers as detergent bottles, milk jugs, trash containers, etc.

That accounts for almost 1/3 of the total worldwide production of HDPE annually. While containers used for consumer goods make up a large portion of products made using blow molding, it is used for many other products as well. Toys, large storage tanks, 55 gallon drums for shipping liquids or powders, and gas tanks are just a few of the other products made with HDPE.

What Products Does Blow Molding Production Create?

Blow molding production can be used to produce high quality, functional, and lightweight containers that are well suited to many uses. While the materials may vary, depending on the product being manufactured, the durability and cost effectiveness of blow molding remains consistent from beginning to end.

Contact Western Case at 877-593-2182 of email us at info@westerncase.com to get a quote for your custom blow molding project.

The Variety of Markets Custom Blow Molding is Used In

The technology behind custom blow molding has made great strides in recent years that allow manufacturers to produce a wide variety of products. These blow molded products have extensive applications in nearly every aspect of life in today’s society. From plastic water containers to parts for the automotive industry, blow molding is producing durable, cost efficient products.

An in house engineering and design team enables Western Case to provide customers with a part design that will be cost effective in manufacturing and functional in its end application. The applications of custom blow molding are nearly endless and some of the products for which it is used may surprise you.

Blow Molding Production Reaches a Variety of Markets Today

  • Automotive ducts: The blow molding production process allows for astounding versatility when producing water and air delivery systems for automobiles. Duct systems can be manufactured using sing or double walled structures providing the sophistication needed in an ever-changing market.
  • Construction and Safety: It’s difficult to find a highway that isn’t under some type of construction. The traffic cones, barricades, and drums that keep the workers, as well as the motorists, safe, are often the result of blow molding production.
  • Sporting Goods: Whether you love hunting, fishing, camping, or all of the above, custom blow molding has probably had an impact on at least some of the equipment that you use. Equipment ranging from duck decoys to backpack frames can be produced using blow molding technology.

The number and variety of products that can be manufactured quickly and efficiently using blow molding are too numerous to mention. Whether you need customized display cases, liquid retention units, or something totally unique to your business, Western Case has the experience and expertise to get you the part you need at the price you want.

Contact Us for Custom Blow Molding

Contact Western Case at 877-593-2182 or email us at info@westerncase.com for a quote on your custom blow molding production project.

The Top 2 Advantages to Using Blow Mold Plastics Production

Blow molding production is a process that takes plastic and turns it into hollow items using an extruder and a mold. The result of this process has certain benefits that include environmental resistance, gas and vapor barriers, resistances against impact, clarity or color, and the ability to be printed on.

Advantages to Using Blow Mold Plastics

There are many advantages to using blow mold plastics, the first of which is the fact that it helps to lower the overall costs of molds. This is because those much lower pressures are used for production. Another benefit is that blow molding carries with it much lower machinery costs if you look at the costs in terms of each unit weight of materials that end up being processed with the machines.

Another advantage to using blow-molding production is the fact that threads can be molded externally on the bottles, adding to the way the bottle is shaped. Additionally, large open ends can be created if needed by choosing a symmetrical mold that can be evenly split open.

Depending on the geometry of the mold and the size of the parison used, we can determine the outside dimensions of each mold for a customizable fit. You can also control the thickness of the walls and manage the weight very specifically with customized design.

Contact Our Blow Molding Production Company to Get Started with Your Project

Contact Western Case at 877-593-2182 of email us at info@westerncase.com to find out more information about how we help you with blow molding. 

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