Small injection molding machine is a type of injection molding equipment used to produce small-sized plastic cups.
Usually with a low injection volume and clamping force.
Key features include a compact design, a high degree of automation and flexibility for small batch production.
Small injection molding machines definition
Generally refer to low-pressure machines and low-parameter standard machines with low injection volume and clamping force of less than 1,000kN, and their common feature is that they can only make small-sized plastic products and have a relatively small appearance.
Small injection molding machines basic structure
- Injection System
- Mold clamping system
- Hydraulic drivetrain
- Electrical control system
- Heating system
- Cooling system
Injection System
This is the core part of the injection molding machine.
Which is responsible for heating and melting the plastic and injecting it into the mold cavity at a certain pressure and speed.
The injection system usually consists of a hopper, a barrel, a heater, a screw (plunger and shunt shuttle in the case of plunger injection molding machines), a nozzle and an injection cylinder.
Mold clamping system
Fix the mold to ensure that the mold is reliably tightened during injection and pressure holding, and perform the mold release operation.
The clamping system includes a fixed platen, a moving platen, a tie rod, an oil cylinder and a push-out device.
Hydraulic drivetrain
Provides power to meet the pressure, speed, and temperature requirements required for each part of the injection molding machine.
Hydraulic systems usually include hydraulic pumps, hydraulic cylinders, hydraulic valves, etc.
Electrical control system
Control the whole injection molding process, including temperature control, pressure control, time control, etc.
Electrical systems typically include PLC controllers, sensors, actuators, etc.
Heating system
Used to heat the barrel and mold to ensure that the plastic remains molten during the injection process.
Heating systems typically include heaters and temperature sensors.
Cooling system
It is used to cool the mold and the plastic to prevent the plastic from curing prematurely during the injection process.
A cooling system typically consists of a cooling channel and a cooling fan.
Small injection molding machines working principle
Heating system
The heating cylinder or heating plate heats the plastic particles to a molten state, ensuring the plastic reaches the desired temperature.
Injection cylinder
The molten plastic is fed from the heating cylinder to the injection cylinder and consists of a screw and a piston that pushes the plastic forward to rotate and compress.
Injection nozzle
The molten plastic enters the injection nozzle, and by controlling the valve switch, the plastic enters the mold smoothly.
Control system
Precise control of the speed, pressure and time of the injection process to ensure that the plastic forms the desired shape in the mold.
Cooling and curing
The plastic is cooled and cured in the mold to form the final product.
Take out the finished product
The mold is opened, and the finished product is taken out of the mold.
Small plastic injection machine types
- High-speed thin-walled special injection molding machine
- Servo injection molding machines
- All-electric injection molding machine
- Vertical Injection Molding Machine
- Hydraulic servo injection moulding machine
- Vertical injection molding machine
- Horizontal injection molding machine
- Low-pressure injection molding machine
High-speed thin-walled special injection molding machine
This type of injection molding machine is designed for the thin-walled structure of cup products.
Which has the characteristics of rapid prototyping and high precision.
Servo injection molding machines
In addition, there are servo injection molding machines, which can achieve high-speed cycles (e.g., the molding cycle can be as low as 10 seconds).
Which is suitable for mass production of thin-walled products such as disposable plastic cups and lunch boxes.
All-electric injection molding machine
At the same time, electric injection molding machines are the preferred choice for the production of small cups.
Due to their high precision,low noise and energy saving characteristics.
Typical parameters include clamping force of 160 tons, cycle time of 10 seconds, material PS, unit weight of 14 grams.
Suitable for the production of high-precision medical cups or food-grade containers.
Vertical Injection Molding Machine
In addition, the vertical structure occupies a small area, and the mold is easy to disassemble and assemble.
Which is suitable for small batch production or test stage.
However, it needs to be picked up manually, and the efficiency is low.
Hydraulic servo injection moulding machine
The hydraulic drive system provides a stable clamping force and combines servo technology to optimize energy consumption.
For example, some hydraulic servo plastic cup thermoforming machines support PP, PET and other materials.
And the quality of the finished product is stable, which is suitable for the production of beverage cups, jelly cups, etc.
Vertical injection molding machine
Occupies a small area, the mold is easy to disassemble and assemble, and is suitable for small batch production (such as models below 60 tons).
It is suitable for the production of small cups or special-shaped cups (such as double-grid cups and frosted cups) below 50ml.
Especially for scenarios that require manual pick-up or complex insert design.
However, the product needs to be taken out manually after ejection, and the stability is slightly worse than that of the horizontal model.
Which is not suitable for mass production.
Horizontal injection molding machine
It has high stability, easy operation, convenient mold installation and maintenance, and is suitable for medium and large-scale production.
It is suitable for the production of PP injection molded cups with standard diameters (e.g. 50ml, 70ml, 90ml),
Especially in scenarios that require high-precision wall thickness control (e.g., deep cup type).
One of the advantages of this injection moulding machine is that the screw type preplasticizer guarantees a stable melt quality and is suitable for the homogeneous filling of highly transparent PP materials.
Low-pressure injection molding machine
Low parameters, small appearance, suitable for overmolding or thin-walled products.
Production of lightweight milk tea cups or cups made of environmentally friendly materials.
Such as PLA suitable for processes with low injection pressure requirements.
