Many plastic products are made by the use of the process known as rotational molding or rotomolding. It is a great way to manufacture everything from custom recycling bins to ping pong balls. It is a great process to make any plastic products that are hollow. This is a very versatile technique to cast plastic products without using any pressure in the process.
Because of the lack of pressure involved, the process of custom plastic rotational molding can be used to make a wide variety of plastic products for a lot less money. Creating molds for custom recycling bins or plastic bulk containers is a cost effective process. The cost effectiveness of the process to make the molds combined with the short time it takes to complete production of various plastic products makes rotomolding an ideal way to manufacture new products. If you are an entrepreneur who has developed a new product, using this process to manufacture your new product may help you get it into stores faster and for less.
What happens in the rotomolding process?
First a mold in the shape of the product is made. The shape is determined by the kind of product that is being made. Custom recycling bins will have a much different kind of mold than what is needed for a ping pong ball. The mold is normally created using sheet metal or an aluminum cast.
- Next a plastic powder is added to the mold. There are other forms of plastic that can be used but powder is the most common kind that is used.
- The mold with the plastic is placed in an oven and heated so it will melt completely.
- As the plastic polymer is melted, the mold is rotated very slowly. As this happens, the plastic coats the sides of the mold until the entire mould is covered with the melted plastic.
- After the plastic has coated the sides of the mold, the mold is moved to a cooling area. Air or water is used to cool the plastic inside the mold. The cooling process causes the melted plastic to return to a solid state only now it is in the shape of the product that is being made.
- Lastly, the new product is removed from the mold and the process is complete.
- That seems like a simple process, is it?
The idea of rotational molding for custom recycling bins and other products is a simple one but the process is more complicated than it may seem. While it is an effective process for making a host of plastic products, you do not have the exact kind of control that you might have in other kinds of molding processes such as injection molding. Ambient humidity and temperature can have impacts on the final project in ways that are different when other molding techniques. The quality of the powder or the material specifications can also impact the end result.
What kinds of plastics are used?
For the most part polyethylene (PE) is used the most in products made by the rotomolding process. It is used in 97% of instances when this is the process used to manufacture plastic products. PE is used because it is easy to mold. It is a versatile material and is easy to acquire. Powders are used because they melt more easily and with a better consistency that other forms of plastic. PE is easy to work with and get into powder form. Sometimes other kinds of polymers are used. They include PVC, polypropylene and polyamide.
What are the other advantages to rotomolding?
- The tooling costs are low. It is very cost effective to design and manufacture the molds that are used to make new plastic products. If you are not sure how many of your new product you are going to want to make, this is a good way to go as the initial investment costs are low.
- It is great for all kinds of shapes. If the product you are working on developing is a shape that is unique or complicated, you can make it easier with rotomolding. It is easy to create just the right shaped mold for your new product.
If you are working on developing a new plastic product, rotomolding can make the process easier for much less.