Molding is an essential process for manufacturing different products in industries. There are various types of molding processes available for production activities. Blow molding and Injection molding are the two most common and popular methods for producing plastics products. They produce high-quality, cost-effective, and high qualified plastic parts.
We can prepare these molds by machining raw materials on CNC machines. CNC turning machining services are essential for manufacturing molds. These methods are different from each other and have different requirements and limits. The manufacturers need to know which molding process suits their required design and development. This article will discuss about blow molding and injection molding. We will explain these methods in the engineering of plastics. I hope these lines will help you in understanding the difference between both methods.
Blow molding is a plastic molding process that is quite like glass blowing. In this process, heated plastic blows into a mold cavity of some specific design to create the required hollow object. Industries design this molding process to produce one-piece open things. It is the best method to form different sophisticated types of plastic bottles.
For blow molding, the raw material in the form of plastic is heat to a specific temperature. Due to unique characteristics, the operator set different temperatures according to the material. Then this heated plastic shifts into a hollow tube like a parison using an extrusion machine.
This parison is then placed into the mold, and using controlled pressure; the air blows into the mold. In this way, the air forces the heated plastic to expand across the interior walls of the mold cavity. Finally, this hollow plastic transforms into the shape of a mold design on cooling. In this way, we can produce our desired product.
Advantages of Blow Molding:
- We use lower pressure level in manufacturing by using extrusion blow molding. Thus, the production and machinery costs are lower in the case of blow molding.
- Blow molding is ideal for producing unique one-piece components. It means no need to connect different parts to manufacture a component.
- This technique is ideal for producing high volume of outputs in minimal time.
Injection molding is generally designed for massive production of precise plastic components. It is ideal to manufacture millions of similar parts of same design. By the use of Injection molding, it is possible to manufacture various parts from small components to entire body panels of cars.
A high level of engineering involves in development of precise molds. Usually, we manufacture these molds on CNC machines using different materials. Xiaman Prime is a good company when it comes to CNC machining services.After finalizing the drawing of a product, the mold need to be manufacture. It is either process on a molding machine or any CNC machine in case of complex dimensions.
Injection molding process starts by melting the material at a very high temperature. Then, this molten material injects into the mold cavity to form the desired shape. In the next stage, the cooling process hardens the plastic polymer to form the mold shape. Later, this molded part ejects to complete this process.
Advantages of Injection Molding:
- High engineering involves in manufacturing of molds used in injection molding. We can produce precise and more efficient components in high volumes.
- Injection molding offers excellent flexibility materials used for molding. Many materials are compatible with injection molding, including thermoplastics, silicones, and resins.
- Injection molding provides the users with various color schemes to use in molding. Liquid colorants and pre-colored resins are helpful to achieve the desired color.
- Injection molding offers high repeatability to the industries. A single mold can be use again and again to manufacture many parts.
Comparison of Blow Molding and Injection Molding in respect of features:
We can understand the difference between these molding processes by their features. Following are the main characteristic differences between them;
Final product difference:
The most noticeable difference between blow and injection molding is the type of part they produce. Usually, blow molding creates hollow parts like bottles, fuel tanks, and containers. In contrast, injection molding is suitable for creating different solid plastic products. Some common parts that can be manufacture through injection molding are housings for computers, bottle caps, etc.
The difference according to the molding process:
The molding process is different in both types of methods. By applying heat, the plastic transformed into a hollow-like tube or parison in blow molding. Then we place the parison into the prepared mold for molding process. Air is generally blown using a plastic extrusion machine to form the final desired shape.
The molding process for Injection molding is different. After heating the plastic material, it injects into the prepared mold and kept under intense pressure,. In this way, the plastic solidified and converted into the same shape as the mold and then ejected to complete the molding process.
The difference according to mold design:
Another significant difference is about the difference in design and type of mold. A lot of precision and accuracy involves in case of injection molding due to the complex parts. It must have a high precision match between mold halves. In this way, the material flow can be perfectly executed. So, it is ideal for molding of plastic products of high complexity and versatile designs. The precision of injection molding makes it more expensive than blow molding.
Blow molding offers more design freedom and flexibility in contrary to injection molding. The precision between movement and molds halves is not that important. There are some other features that need regular monitoring. We track variables like wall thinning, air leaks, air pressure control, and flash to perform ideal process.