Issue 191 2021-03-25 Souscrire

5 Minutes to Know HDPE Blow Molding

5 Minutes to Know HDPE Blow Molding

What is HDPE Blow Molding?
HDPE Blow Molding is the process of molding a softened thermoplastic hollow form called a Parison. This Parison is first vertically extruded from the Die Head of a Blow Molding Machine and then, it is inflated against the cooled surface of a closed mold, the expanded plastic then solidifies into a hollow HDPE product that needs none or very little finishing processes after the Blow Molding.

There is a variety of HDPE plastic products in the market today made by Blow Molding, the most common examples include plastic bottles for cleaning agents and lubricant oils, jerry cans for edible oils, water tanks and drums for chemical liquids.

Extrusion HDPE Blow Molding: Types of Extrusion Systems
There are 2 types of Extrusion systems in HDPE Blow Molding, which are:

Continuous Extrusion
Non-continuous Extrusion (with an Accumulator Head)

How can we know which HDPE Extrusion system is adequate for the product that will be made?
The key is in the size and weight of the product, and the amount of HDPE material necessary to produce it, this is called the shot size. The shot size is the length and weight of the Parison that will be ejected from the extrusion die head of the Blow Molding Machine.

In a Continuous Extrusion Blow Molding system, as the Parison is extruded continuously during the blowing cycles, the product’s weight and size should not be too big, as it will require a larger shot size and can make it difficult to control that the temperature of the bottom and top of the Parison remains constant.

In a Non-Continuous Extrusion Blow Molding system, the melted HDPE plastic material is first accumulated into a chamber in an Accumulator Head, it is then vertically extruded between 2 clamping plates in a single shot with high injection speed, then the 2 clamping plates close, and the blowing cycle begins.

At the time of calculating the shot size, it is extremely important to consider not only the dimensions and weight of the plastic product, but also the flasher. The flasher is the excess plastic that remains in the product after the blow molding process is finished and the plastic product is formed and then taken out of the mold.

In this article, we will introduce a little bit about the Non-Continuous type of Extrusion HDPE Blow Molding, the industries that benefit from this technology, the applications, the advantages of using an Accumulator Head, and some examples of these machines.

First, it is important to know what these types of Blow Molding Machines are called: Accumulator Head Blow Molding Machines.

HDPE Blow Molding Machines – Accumulator Head

To start, these are some of the industries that benefit from Accumulator HDPE Blow Molding and the products that can be made with this technology:

Automotive (Air ducts and different HVAC system ducts)
Household products (Tables, Seats, Baby Potty, HDPE Water tanks, PC Water Tanks)
Industrial (Open top drums, L ring drums for chemical liquids, IBC tanks, Floats for Solar Panels, Packing vessels)
Fitness & Sports equipment (Basketball Hoop base, Stackable Steps).

READ ALSO: HDPE Blow Molding Application

Advantages of Using Accumulator Head Blow Molding Machines

A non-continuous type Blow Molding Machine (Accumulator Head Blow Molding Machine) has many advantages over a Continuous type Blow Molding Machine when it comes to producing high quality large hollow plastic products, some of them are:

Better Control of the Parison Temperature.
When the mold is ready to close, the plastic Parison is ejected at once and the blowing cycle can start, this means that the Parison does not have to be kept outside for a long time, and therefore, its temperature remains constant along all the points of the Parison, resulting in a high-quality product.

Increased Strength of the Production.
As the die head can stock the melted plastic material, a two heart-shape flow channel can be designed for the plastic flow inside the die head, this design allows a weld line-free extrusion, which increases the strength of the production.

Stronger Clamping Force.
The structural design of the Accumulator type Blow Molding machines allows the clamping unit to have a stronger clamping force, this force is equally distributed along the clamping plates, avoiding any air leaking during the product formation.

Examples of HDPE Blow Molding Machine with Accumulator Head

As customers' production demands become higher, we are challenged to step up our machines' designs and production cycle times, without compromising our so renowned efficiency and good quality. Thanks to our team of Engineers and specialty technicians, we have managed to achieve this goal in many of our most recently manufactured Blow Molding machines, thus, improving overall performance.

One example is our latest Double L Ring Drum making machine, with production ranges from 200L to 250L, with this machine, we have achieved a faster Injection Speed and Mold close-open movement, therefore, reducing the cycle time by 5 to 6 seconds!

Furthermore, our customers can also increase the strength of the HDPE drums for the drop test standards, by adding a Post Cooling Unit, especially designed for the narrow mouth 200L to 250L Double L Ring HDPE drum. Due to its high cooling capacity, it cools down the drum again and helps to complete its formation with an enhanced strength.

READ ALSO: Blow Molding HDPE Drums

Accumulator Head HDPE Blow Molding Machines Installation during COVID-19 times.

For a machine to be successfully installed, Chen Way is always committed to train the machine operator personnel and further give the corresponding commissioning services, this to assure the HDPE Blow Molding Machine can run smoothly and the customers can reach their production output goals without trouble.

And during these difficult times, it has not been the exception; Chen Way team has done their best to assist our International customers through different channels for several machines’ installations that were planned before the COVID-19 travel restrictions. We dispatched machines to Dubai and India that arrived when the pandemic was still very serious, thus our engineers could not travel to the customer’s factory. However, the installation was successful after online assistance and thanks to the efforts of our agent partner in India, KYMC team.

To find out more insight details about the issues faced in the Blow Molding market in India during the pandemic, please watch the below interview made to our Indian agent, in which he talks about the advantages of having a local partner in India, suggestions to foreign manufacturers/companies who plan to enter the Indian market, and how manufacturers provide support to local dealers under pandemic circumstances: