Rotational Moulding: The Process & Advantages


Rotational moulding, also known as rotomoulding, is a plastics moulding technology which is ideal for making hollow articles. It is a casting technic but unlike most other plastics processes there is no pressure involved. Moulds for the process are relatively inexpensive as they do not have to withstand pressure and therefore relatively short production runs can be made very economically.


Rotomoulding is used to make a very diverse range of products. The process offers the product designer exceptional freedom as just about any shape can be produced. There is almost no limit to the size of mouldings and there are literally thousands of applications.


The Process


The concept of rotational moulding is very simple. A plastic material, normally in powder form is placed into a hollow mould, usually made from cast aluminium or fabricated from sheet steel. The mould is closed and rotated slowly on two axis. The mould is then heated in an oven whilst rotating and the polymer gradually melts and ‘lays-up’ on the inside of the mould. Once the polymer powder has fully melted the mould is moved to a cooling station and cooled usually with air and sometimes a fine mist of water. As the mould cools the part solidifies. When the material has finally cooled sufficiently to release away from the mould surface the process is stopped and the product is taken out of the mould (de-moulded).


Whilst the concept of rotational moulding is extremely simple anyone who has ever been involved in the process will tell you that it is in fact extremely complicated. It is a casting process and there is normally no pressure involved which means that the material cannot be controlled in the same way as high pressure processes such as injection moulding. There are many variables that can affect production and the end product such as ambient temperature and humidity, type of mould, material specification and powder quality.


Materials


Today the industry is heavily dependent on Polyethylene (PE) and 97% of rotomoulded products are made from this material. Polyethylene is a versatile, easily mouldable and readily available polymer which has come to dominate the process. Rotomoulding is a casting technique in which powder is nearly always used rather than granules, meaning the material must be ground. Polyethylene is relatively easy to grind at ambient temperatures.


The development of other polymers has been hindered by the fact that the process is relatively long and therefore aggressive on polymers, however there is some usage of PVC (usually in liquid plastisol form), Polypropylene and Polyamide (PA6, PA11 & PA12). Many of these non-Polyethylene materials are difficult to grind and most need to be made into powder using cryogenic grinding – that is freeze grinding, which is a more costly process. There is a welcome increase in R&D to expand the range of materials available to the industry.


Uses And Advantages Of High-Quality Plastic Pulverizer Machine


When deliberating on high-quality pulverizer machines, take a look at the plastic pulverizer machine.


The plastic pulverizer is a piece of magnificent equipment used in crushing plastic into small and tiny sizes.


Former plastic pulverizers are highly difficult and complex and the results it produced are inaccurate sometimes.


To solve this problem customized powder pulverizer machines are introduced, and they generate colorful masterbatch.


All thanks to the manufacturer of the high-quality pulverizer. With this machine, you have the chance to achieve standard quality and colorful powder used in the manufacturing and compounding of masterbatch.


Also, the plastic pulverizer machines give the perfect and equal size of particles which ensures an adequate blending and mixing of additives.


Furthermore, plastic compounds such as Polycarbonate (PC), Polyamide (PA), and Polyethylene terephthalate (PET) are processed in an ambient heat through this processor.


Once this is ongoing, the downstream fan will transfer the end product into a cyclone from the disc mill.


One notable thing is that this whole process is totally mechanical but the control cabinet will maintain and regulate all the activities.


However, for advanced and latest high-quality pulverizer to smash your plastic materials, buy PVC pulverizer from a reliable manufacturer.


Obviously, this is the most recommended option for your best processing services.


Materials That Can Be Ground Using Plastic Pulverizer Machine


PVC pulverizer machine can be used to grind many items such as buckets, bottles, pipes, and jugs.


After grinding, these materials are converted into granules which are afterward ready to be remolded into different other products.


A plastic granulator is normally large which allows it to grind much plastic at once.


More so, you can also buy PVC pulverizer which is smaller in size for home use.


High quality plastic pulverizer machine can be used to grind thermoplastic materials such as Low-density polyethylene (LDPE) and ethylene vinyl alcohol (EVA).


Other materials include Polyvinyl Chloride (PVC), Polyester, cross-link, ABS, High-Density Polyethylene (HDPE), polyethylene terephthalate (PET), and Nylon.


When you buy PVC pulverizer, you can also use it to pulverize film waste, sheets, and tubes of soft and hard, impact, and brittle resistant materials.


High-quality pulverizer is easy to clean and maintain and has an economic option. It doesn't consume power and it has a robust design. In fact, time and effort are saved by its ease of operation.


Why You Should Go for an Air Cooler Over an Air Conditioner?


In the ongoing debate of air conditioners vs air coolers, we list down few important pointers that will offer a clear idea of why you should opt for an air cooler.


But first things first, should you buy an air cooler?
A cooler can be used by everyone, especially people living around hot and dry weather. One can choose from a dessert cooler, a window cooler or even a personal cooler, depending on the requirements.


Read on to know more about why to choose an air cooler over an air conditioner.


Have you ever wondered about how an AC or an air cooler functions and how does it affect the quality of air in your home?


An air conditioner circulates the internal air of the room over and over again, whereas an air cooler pulls fresh air from outside and then cools it down. Also, air cooler doesn’t make the air overly dry like an air conditioner. Because of the way it operates, an air cooler offers better quality of air for your room. So much so, that the air circulated from an air cooler is preferable for people with asthma or dust allergy.


Economical Alternative


When it comes to value for money, an air cooler definitely scores high over an AC. Even though both end up cooling the room, an AC can cost anything ranging from ?30,000 to ?60,000, whereas a cooler will be available from ?5000 to ?15,000. Also, apart from the initial cost of purchasing, even the operating cost of an air cooler is less than an AC. You can approximately expect 80% less electricity bill from a cooler as compared to an AC, making it economical in the long run.


Going green is something that concerns all of us, and air coolers trumps the card here as well. Air conditioners use CFC (Chlorofluorocarbon) and HFC (hydro-chlorofluorocarbons) as their refrigerant, which is quite harmful to the environment. On the other hand, air coolers are eco-friendlier, since they use water as the refrigerant.


Industrial Cooling Fans: Overview, Benefits, and Applications


It is quite common to see various types of fans in industrial facilities. They are used to regularize the airflow to various structures or parts of the building. There are several types of industrial fans, which are categorized based on their designs, applications, and so on. Industrial cooling fans and industrial cooling blowers are two types of industrial fans used across the industrial facility for cooling purposes. Do you want to know how these fans differ from other types?


This post gives an overview of industrial cooling fan, their beneficiary features, and industrial applications.


What are Industrial Cooling Fans?


Industrial fans are the mechanical devices that create fluid flow for industrial purposes. The industrial fans often considered as fluid displacers since the air or gas is displaced from one point to another due to the rotational motion of blades. The primary purpose of the industrial cooling fans is to blow cold air and drive hot air out of the environment. Therefore these industrial fans are also called industrial cooling blowers. However, cold air intake or hot air exhaust depends on the design and construction of the specific fan. Unlike other industrial fans, the cooling fans have large diameters, which help them produce large volumes of air and low pressures, as required in several environments. Regardless of the fan design, the fundamental components of industrial fan remain the same. They are discussed in detail in the next section.


Fundamental Components of an Industrial Cooling Fan Assembly


Industrial cooling fans comprise a motor, a rotor shaft, and the blades or impellers. These are the fundamental components of the assembly. Check out on the function of these fundamental components and other important features in a fan assembly.


Motor:


An electrical motor is the primary input source in an industrial cooling fan assembly. The motor can be AC or DC as per the design and performance requirements. The motor transfers’ electric power to the hub of the rotor shaft as the energy input.


Rotor Shaft:


The rotor shaft is connected to an electric motor with an intermediate hub. The hub transfers electrical energy to the rotor shaft. The shaft rotates on receiving this electrical energy. This all suggests the conversion of electrical energy into mechanical to get the desired output.


Impellers/Blades:


The blades or impellers are the components that cut through the surrounding air to form a fluid drag. The blades are mounted on the rotary shaft at a specific distance. The blades rotate to push or exhaust air drag. These blades can be designed in multiple shapes according to aerodynamic standards.


Fan Casing:


The fan casing is a metal casing that houses the whole assembly. The main purpose of fan casing is to protect the assembly from dust, external damage, as well as the environmental impact such as corrosion, moisture, dust, etc.


Fan Mountings:


The mountings are bearing on which the fans are fixed on. The industrial cooling fan assembly can be mounted by using a ball or sleeve bearings. The bearings are the foundation of the fan assembly therefore, the quality and function are very important.


These components of the industrial fan assembly remain constant irrespective of the types of industrial cooling fans.