Plastic is one of the world's most widely used materials. Think of almost any purpose and you will find a kind of plastic that can fulfill that purpose. Of course, there are different methods to produce different types of plastic. One of these methods is structural foam molding.
This method of producing plastic products is closely related to injection molding. In the latter method, the polymer is melted and then injected into the mold. Most plastic parts are made in this way.
In the manufacturing of products made of thermoplastics, structural foam molding is often the preferred method of processing. Thermoplastics are polymer resins products that liquefy when heat is applied and solidify when they are cooled. Because this process can be repeated time after time, thermoplastics are ideal for recycling.
In the injection method conventionally used to produce plastic parts, an extremely high pressure is applied to get the polymer to flow into the mold. When using the structural foam method to process thermoplastics, however, low pressure is applied instead. There are two methods of making the polymer flow into the mold at low pressure.
In the one method, you need to use a special machine that adds an inert gas into the molten polymer. This gas causes the polymer to froth. The foamy polymer then spreads into and throughout the entire mold.
Another method is to use polymer that has special chemicals added to it. These chemicals act as blowing agents. When the polymer melts, the blowing agents cause a chemical reaction which releases gases. These gases then cause the polymer to froth. For this method, you can use conventional molding machines.
No matter what method is used to get the frothy polymer into the mold, the end product is the same. It is a thermoplastic that has five to fifteen millimeter thick outer walls that make it strong, hard and impact resistant. The center is foamy so that the plastic part is light. It is also a good insulator against sound and changes in temperature.
One of the main advantages of applying low pressure to produce a foaming action is that the frothy polymer can spread much further throughout the mold. This makes it ideal to fill up large molds. The result is that only the size of the machines can really limit the size of the parts it is possible to produce.
While other injection methods use molds made of steel, the structural foam method uses aluminum molds. These are not only lighter, but also much cheaper to use. In addition, the cost of setting up the tools and machines for this process is lower too. This improved cost efficiency makes the method ideal for producing parts in low volumes.
The thermoplastic most commonly used for structural foam molding is high density polyethylene, also known as HDPE. Polyethylene is typically used in making pipes, plastic bottles for drinks, as well as gas tanks for cars. Other thermoplastics that can be processed at low pressure include acrylonitrile-butadiene-styrene and polypropylene. Acrylonitrile-butadiene-styrene or ABS is commonly found in cars, the outer parts of computers and other electronic products, waste pipes and pipe fittings. Polypropylene or PP is also found in car interiors, as well as plastic beakers and syringes.
This method of producing plastic products is closely related to injection molding. In the latter method, the polymer is melted and then injected into the mold. Most plastic parts are made in this way.
In the manufacturing of products made of thermoplastics, structural foam molding is often the preferred method of processing. Thermoplastics are polymer resins products that liquefy when heat is applied and solidify when they are cooled. Because this process can be repeated time after time, thermoplastics are ideal for recycling.
In the injection method conventionally used to produce plastic parts, an extremely high pressure is applied to get the polymer to flow into the mold. When using the structural foam method to process thermoplastics, however, low pressure is applied instead. There are two methods of making the polymer flow into the mold at low pressure.
In the one method, you need to use a special machine that adds an inert gas into the molten polymer. This gas causes the polymer to froth. The foamy polymer then spreads into and throughout the entire mold.
Another method is to use polymer that has special chemicals added to it. These chemicals act as blowing agents. When the polymer melts, the blowing agents cause a chemical reaction which releases gases. These gases then cause the polymer to froth. For this method, you can use conventional molding machines.
No matter what method is used to get the frothy polymer into the mold, the end product is the same. It is a thermoplastic that has five to fifteen millimeter thick outer walls that make it strong, hard and impact resistant. The center is foamy so that the plastic part is light. It is also a good insulator against sound and changes in temperature.
One of the main advantages of applying low pressure to produce a foaming action is that the frothy polymer can spread much further throughout the mold. This makes it ideal to fill up large molds. The result is that only the size of the machines can really limit the size of the parts it is possible to produce.
While other injection methods use molds made of steel, the structural foam method uses aluminum molds. These are not only lighter, but also much cheaper to use. In addition, the cost of setting up the tools and machines for this process is lower too. This improved cost efficiency makes the method ideal for producing parts in low volumes.
The thermoplastic most commonly used for structural foam molding is high density polyethylene, also known as HDPE. Polyethylene is typically used in making pipes, plastic bottles for drinks, as well as gas tanks for cars. Other thermoplastics that can be processed at low pressure include acrylonitrile-butadiene-styrene and polypropylene. Acrylonitrile-butadiene-styrene or ABS is commonly found in cars, the outer parts of computers and other electronic products, waste pipes and pipe fittings. Polypropylene or PP is also found in car interiors, as well as plastic beakers and syringes.
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