The die head is an extremely crucial component of the extrusion blow molding machine. It serves as the gateway through which the melted resin is transformed into a tubular parison, a fundamental step in the production of various plastic products.

When the extrusion blow molding process commences, plastic resin in pellet form is fed into the machine. Inside the heating barrel, the resin is subjected to high temperatures, gradually melting into a viscous, molten state. This molten resin then flows towards the die head under the pressure generated by the screw or other feeding mechanisms. Once it reaches the die head, the carefully engineered structure of the die head guides the resin's flow, causing it to emerge as a continuous, hollow tube - like structure known as a parison.

One of the most significant functions of the die head is its ability to adjust the thickness of the parison according to the requirements of different products. For products that require a more robust and durable structure, such as large - capacity industrial containers, the die head can be adjusted to produce a parison with a relatively thick wall. On the other hand, for more delicate items like small cosmetic bottles or thin - walled packaging containers, the die head can be fine - tuned to extrude a parison with a thinner wall. This adjustment is achieved through a combination of factors, including the design of the die head's internal channels, the temperature control within the die head, and the pressure applied to the molten resin.

• Continuous Type Die Head: In the continuous type die head, the molten resin is extruded continuously in a steady stream. This type of die head is well - suited for producing products with a relatively simple and consistent shape, such as standard - sized plastic bottles. It operates in a continuous manner, allowing for high - volume production with relatively stable output. The continuous extrusion process ensures a smooth and uniform flow of the molten resin, which is beneficial for maintaining the quality of the parison.

• Accumulator Type Die Head: The accumulator type die head, on the other hand, has a storage chamber where the molten resin is accumulated. When a sufficient amount of resin is stored, a valve is opened, and a large volume of resin is rapidly extruded in one go. This type of die head is particularly useful for manufacturing products with larger wall thicknesses or complex shapes. For example, when producing large - scale industrial drums or automotive parts, the accumulator type die head can provide the necessary amount of resin in a short period, enabling the formation of thick - walled and sturdy products.

• Single Die Head: A single die head is the most basic configuration, where there is only one extrusion point. It is commonly used for small - scale production or for manufacturing products that do not require high - volume output. For instance, in a laboratory - scale production setup or for producing specialized, low - volume plastic items, a single die head can be a cost - effective and straightforward solution.

• Multi Die Head: Multi - die heads come in various configurations, such as 2 - head, 3 - head, 4 - head, 6 - head, 8 - head, 10 - head, and 12 - head setups. These are designed to increase production efficiency significantly. Each head in a multi - die head setup can extrude a parison simultaneously. This is highly beneficial for high - volume production lines, especially in industries where a large number of identical products need to be manufactured quickly. For example, in the beverage packaging industry, multi - die heads can be used to produce a large quantity of plastic bottles in a short time, meeting the high - demand requirements of the market.

• Monolayer Die Head: A monolayer die head is designed to extrude a single - layer parison. This is suitable for products where a single layer of plastic material is sufficient to meet the product's requirements, such as basic food - grade packaging containers or simple plastic utensils. The monolayer die head is relatively simple in structure and is often more cost - effective for mass - producing basic plastic products.

• Multi - layer Die Head: Multi - layer die heads are more complex and are used when products require multiple layers of different plastic materials. These layers can have different functions, such as providing better barrier properties, improving product strength, or enhancing the aesthetic appearance. For example, in the packaging of sensitive products like pharmaceuticals or high - end food products, multi - layer die heads can be used to create parisons with an inner layer that is compatible with the product's content, a middle layer that provides strength and rigidity, and an outer layer that offers a smooth and attractive finish.