Injection Molding Machines: A Comprehensive Introduction
Injection molding machines, also known as injection machines, are specialized devices for manufacturing plastic products. They play a crucial role in the plastic manufacturing industry.
What is an Injection Molding Machine?
Most injection molding machines are mainly composed of two parts: the injection unit and the clamping unit. The injection unit is responsible for heating plastic pellets into a liquid state. The clamping unit holds the mold and provides the force required for actions such as mold closing and locking. Injection molding machines offer two major advantages: high processing speed and cost - effectiveness.
How to Select an Injection Molding Machine?
Special attention should be paid when choosing the type and size of the injection molding machine. Larger products require larger machines and usually need more professional attention to operate properly. Injection requirements such as mold opening stroke, clamping force, injection volume, screw compression ratio, injection speed, appearance and performance of the finished product also need to be carefully considered. The range of required products will determine the type of injection molding machine needed.
Types of Injection Molding Machines
There are various types of injection molding machines, which are generally classified in the following ways:
Classification Method 1: Power Drive Method
- Hydraulic Injection Molding Machines: As the name implies, they are driven by hydraulics. Although this method is highly effective, it has a drawback in that they cannot be left idle. They must operate continuously to maintain a constant temperature of the molten plastic. Starting and shutting down require time and special attention to avoid damaging the machine. During startup, plastic that has not reached the appropriate temperature needs to be discarded for recycling. During shutdown, it may be necessary to remove unwanted resin from the barrel and screw to prevent the resin from hardening and clogging the barrel during startup.
- All - Electric Injection Molding Machines: Compared with hydraulic injection molding machines, all - electric injection molding machines are more expensive. However, they do not need to operate continuously and do not require temperature adjustment. Injection molding is relatively stable, and the efficiency is higher. All - electric injection molding machines have no hydraulic system, so there is no risk of machine leakage.
- Hybrid Injection Molding Machines: Hybrid injection molding machines are highly efficient and cost - effective, combining the advantages of hydraulic and all - electric types. They are currently widely used by many companies. These machines are moderately priced and quite energy - efficient, which is important when energy costs are a major consideration. Hybrid injection molding machines use a servo motor to drive a hydraulic pump, and the hydraulic pump provides hydraulic pressure to power the components of the machine. The clamping mechanism is simpler, more precise, and more durable, greatly reducing maintenance costs. Servo - hybrid machines can provide higher injection pressure and clamping pressure than all - electric machines.
Classification Method 2: Operation Direction
- Vertical Injection Molding Machines: As the name suggests, vertical injection molding machines operate vertically. They are usually used to manufacture relatively small parts and take up less floor space, which is very space - saving. Vertical injection molding machines are often combined with a rotary table or conveyor belt to improve production efficiency.
- Horizontal Injection Molding Machines: Horizontal injection molding machines are the most widely used injection molding machines. They have a lower body height, fast molding speed, and are convenient for operation and maintenance.
Classification Method 3: Applicable Raw Materials
- Thermoplastic Injection Molding Machines: Thermoplastics melt into a liquid when heated and solidify when cooled. Common thermoplastics include PE, PP, ABS, TPU, etc. Thermoplastic injection molding machines heat plastic pellets and then inject the liquid molten plastic into the mold. After cooling, the plastic returns to a solid state, and the plastic part is ejected from the machine.
- Thermosetting Plastic Injection Molding Machines: Thermosetting plastics change from a liquid to a solid when heated. This transformation usually occurs only once, so they cannot be recycled like thermoplastics and are thus less harmful to the environment. Common thermosetting plastics include FRP and melamine. Thermosetting plastic injection molding machines inject the plastic liquid into the mold and heat it. The plastic solidifies to complete the final product.
In conclusion, injection molding machines come in a wide variety of types, each with its own characteristics and applications. Understanding these aspects can help manufacturers make more informed decisions when choosing and using injection molding machines.
