Types of plastic moulding
In today’s world of manufacturing, plastics are used to make a whole range of products, from automotive body parts to in some cases human body parts. Each moulding process requires a special manufacturing process that moulds the parts based on their specifications. In this article, we will be looking at 4 different types of plastic moulding techniques and their advantages and applications.
This type of moulding is well suited for hollow objects, like bottles. The blow process follows the basic steps that you would find in glass blowing. A parison, or heated mass of plastic, is placed in a tube and then inflated by air. The air then pushes the plastic against the mould meaning that it takes the form of its desired shape. The plastic is then left to cool, then ejected once it is at its desired temperature.
The blow mould process is perfectly designed to manufacture at high volume for one-piece hollow objects. This moulding process creates uniformed walled containers, perfect if you’re looking to manufacture lots of bottles.
This process is well suited for larger objects such as auto parts. The name of this moulding method says it all; the heated plastic material is placed into a heated mould and is then compressed into shape. The heating process, which is also known as curing, ensures that the part will maintain its shape and functionality when in use. Like with other moulding methods, once this part has been shaped, it is then cooled and removed from the mould. If sheeting plastic material has been used, then it is first trimmed whilst still in the mould before the part is removed.
Compression moulding is suitable for high-strength compounds such as thermosetting resins, fiberglass and reinforced plastics. The superior strength properties of the plastic material used in the compression mould help make this method a valuable process for the automotive industry.
This moulding method is well suited for high-quality, high-volume part manufacturing. Plastic injection moulding is seen to be the most versatile of all moulding techniques. The presses that are used in this moulding process vary in size and are rated based on their pressure and tonnage. Large injection machines can create car parts, whereas, smaller machines can produce very precise parts. During the injection moulding process, there are many types of plastic resins that can help increase its flexibility.
This production process itself is fairly straightforward; however, there are a variety of enhancements and customisation techniques that can be used to help produce a unique and desired finish or structure to the product. Injection moulds contain cavities so that when the melted plastic is injected it will fill the cavities and therefore, take the desired shape. Once the plastic is cool, the parts are then ejected using pins.
The initial mould making costs is relatively high; however, the cost per part is very economical. Low part cost along with resin and finish options have all contributed to injection moulding’s popularity in today’s manufacturing industry.
This moulding process is well suited for large, hollow, one-piece parts. It is done by using a combination of high temperatures and rotational movements to help coat the inside of the mould and form its shape. By having a constant rotation of the mould, it helps to create centrifugal force which produces evenly-walled products. Due to the fact this type of moulding is suited to large, hollow containers, it is not a fast moving process.
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You might like to read our previous article on ‘The importance of plastics in the modern day.’