The extrusion moulding process is known for making tube-like objects such as hoses and pipes. The products can be made up of various materials depending on their requirement. It is widely known among manufacturers for creating a variety of products with cross-sectional profiles. The raw material, in the moulding process, is pressed through a die. The shape of the die is decided upon by the profile of the product.
The hollowed PET bottles used in the industry of packaging are a great example to understand the process of extrusion moulding. The PET bottles are made with single stage molds through the process of extrusion moulding, which gives a desired shape to the bottle while retaining the hollow in its center.
Understanding Extrusion Moulding
The extrusion moulding process is accomplished via the means of an extrusion machine. In simple terms, the final product is made by pushing the raw material through a die. The motor of the machine feeds the raw material through a heating chamber. When the raw material gains the consistency of fluid, it is passed through dies where the shaping takes place. The product will take whatever shape the die has. Once the cooling is done, the finished product one gets is a solid tube.
However, when it is to manufacture hollowed objects, the process of extrusion blow moulding is used. It is a more specific process. In this process, one end of the object is kept open to introduce compressed air to the tube-like product. The compressed air is pushed through the object. The product is removed after it takes its shape, cooled off, and solidifies.
Invention of the Extrusion Process
The process of extrusion moulding is derived from the earliest methodology of extrusion. Extrusion tools were developed during the late 1800s. This was the time when the extrusion process was used for producing sausages. Gradually, evolution started to take place in the process of extrusion.
During the 1930s, a single-screw extrusion tool was devised for producing pasta. The machine was used to mix flour with water. Thereafter, the tool pressed it through the extruder for making the layers of pasta. As the shear rate was not sufficient enough, the process was not highly effective for the users. Besides, the process evolved with time, and extruders were developed to produce expanded curls.
The evolution in the area of extrusion continued with time. Therefore, it has gained importance in a variety of industries, today.
The Popularity of the Extrusion moulding Process
The extrusion process has gained momentum in different parts of the world because of its employability in creating the most intricate cross-sections. Moreover, processing of the most brittle materials becomes possible with extrusion methodology. Also, an enhanced surface finish of the product is ensured by the extrusion process.
Looking at the extrusion process in comparison to the process of drawing, one can observe the limitations posed by drawing. The process is used for making diverse objects like metal bars, wires, and other tube-like objects. However, it does not equip as many changes as required in a single step for developing various ranges of objects. Hence, this gives extrusion an edge over the process of drawing.
Different Processes of Extrusion
Although the net result of an extrusion process is to create tubular objects using different materials, there are different types of extrusion processes.
Cold Extrusion
In the process, the moulding material is pushed through the die at room temperature. The material is joined together to create a solid shape in a die.
Hot Extrusion
Contrarily, in hot extrusion, the material that is pushed through the die is in a molten state. Therefore, the metal is preheated before shaping. It is considered an ideal way for extrusion.
Micro Extrusion
It is a comparatively newer development in the area of extrusion moulding. It is useful for making objects of micro size. Micro-sized dies that can withstand extreme pressures are required for micro extrusion.
Advantages of Extrusion Technology
The most widely known advantages of extrusion technology are listed below.
- Consistent Cross-Sectional Design: A constant shape is maintained in the moulding due to the symmetry maintained in the cross-sections. It, also, gives the flexibility in creating a diverse and complex range of designs.
- Cost Factor: Extrusion technology is a cost-effective method. In the case of thermoplastics, the melting and hardening can be applied multiple times. In some cases, the leftover can be reused instead of disposed of them.
- Alterations post-extrusion: The material is still hot when it leaves the extruder. Therefore, it gives an opportunity for desired alterations to the manufacturer. If required, the manufacturer can make specific alterations to the product with the use of dies and rollers.
Summing Up
Hence, one can understand the importance of extrusion technology in the area of moulding, since its inception. The technology facilitates the manufacturing of different cross-sectional products for various industries.
Acme Drinktec Solutions is a renowned name in the domain of mold manufacturing. It is one of the leading single stage molds manufacturers in India, and has been operating in the industry for over a time span of 20 years.
