What is An Injection Molding Machine? What are The Types?

16 Nov.,2022


horizontal injection moulding machine

What is An Injection Molding Machine? What are The Types?

Injection molding machine, also known as injection machine, is a special machine for manufacturing plastic products. There are many types of injection molding machines, which can usually be distinguished by the following methods: driving mode, mold opening and closing direction, applicable raw materials, mold clamping structure, and injection structure.

What is An Injection Molding Machine?

Injection molding machine, also known as injection machine, is a special machine for manufacturing plastic products. Most injection molding machines are mainly composed of two parts: injection device and clamping unit. The injection unit is responsible for heating the poured plastic pellets into liquid. The clamping unit is used to carry the mold and provide the force required for mold closing, mold clamping and other actions. In general, the injection molding machine has the advantages of fast processing and fare economical cost.

How to Choose An Injection Molding Machine?

Special attention should be paid to the selection of injection molding machines. After thinking about the nature of the injection product, you must first understand the size of the mold and the product. Larger products require a larger injection molding machine, followed by more professional injection molding. The machine performance of the machine should pay special attention to the injection requirements such as mold opening stroke, mold clamping force, injection volume, screw compression ratio, injection speed, finished product appearance, performance, etc. Each injection product has to be considered and the key point to note is to do your study before purchasing.

What are The Types of Injection Machines?

There are many types of injection molding machines, which are usually distinguished by the following methods:

Classification Method 1: Drive Method

Hydraulic Injection Molding Machine

The injection power of the hydraulic injection machine is mainly hydraulic. Because the hydraulic plastic injection molding machine cannot be idle, it needs to keep running all the time, otherwise the machine may be broken; when making plastic components, it is also necessary to control and adjust the temperature of the machine, otherwise it is easy to make scrap.

All-Electric Injection Molding Machine

Compared with the hydraulic injection machine, the price of the all-electric injection molding machine is higher, but the all-electric injection molding machine does not need to operate on standby, nor does it need to adjust the temperature, so the injection molding products are relatively stable and can be more efficient. The all-electric injection machine has no hydraulic system, and there is no risk of liquid leakage in the machine.

Hybrid/ Servo Hybrid Injection Molding Machine

Hybrid injection molding machine has the characteristics of high efficiency and economic benefits. It is a model that integrates the advantages of hydraulic type/all-electric type and is transformed. It is a plastic injection machine used by many companies now, which balances the other two. Advantages and disadvantages of hydraulic press, there are medium machine cost and energy cost. We all know that energy cost is definitely a major consideration when choosing an injection molding machine. For this purpose, the servo oil-electric injection machine is equipped with a high-precision servo motor to achieve the same saving as the all-electric type. Considering the cost of electricity, the machine and clamping mechanism are also simpler, more accurate and durable, which greatly reduces the cost of maintenance. The servo hybrid type not only has the advantages of cost saving, but also has higher injection and pressure holding pressure than the all-electric type, which is a major breakthrough in the hydraulic injection molding machine.

Classification Method 2: Trend of Switching Mode

Vertical Injection Molding Machine

As the name suggests, a vertical injection molding machine is a vertical injection molding machine. It is usually used to manufacture relatively small molds. It has the advantages of being able to inject more types of products and saving space. If the vertical injection machine is equipped with a rotary table or conveyor belt, it can effectively improve production efficiency.

Horizontal Injection Molding Machine

The horizontal injection molding machine is the most widely used and most used model. It is characterized by a relatively low-height body, fast molding, and convenient operation and maintenance. Automatic production.

Classification Method 3: Applicable Raw Materials

Thermoplastic Injection Molding Machine

Thermoplastics will melt into liquids after heating, and turn into solids after cooling. Common thermoplastics include PE, PP, ABS, TPU, etc. Generally, plastics that soften when exposed to heat are mostly thermoplastics. Thermoplastic plastic injection machine uses the characteristics of thermoplastic plastic to inject liquid plastic into the mold after heating the plastic pellets. After cooling, the plastic returns to a solid state, and then the plastic parts are pushed out of the machine.

Thermosetting Plastic Injection Molding Machine

The characteristics of thermosetting plastics are that they will change from liquid to solid after heating. This transformation can usually only be formed once and cannot be recycled like thermoplastics, so it is not environmentally friendly. Common thermosetting plastics include FRP and Melamine. The thermosetting plastic injection machine is to inject the plastic liquid into the mold after processing, and after heating, the plastic parts are solidified to complete the production.

Powder Injection Molding Machine

Powder injection molding can also be called "metal injection molding" (MIM), "ceramic injection molding" (CIM). The raw materials are precision-treated fine metal or ceramic powders and bonding materials. Common applications are portable products, smart devices, electronic products, etc. Powder injection is often used to manufacture small parts with high precision and complex appearance, especially metal. The parts produced by powder injection have the characteristics of high strength and high density. After the metal powder and bonding material of the powder injection machine are processed, they will become small molding raw materials similar to plastic particles, and then the injection molded workpiece will be cleaned, heated, etc. Post-processing, and finally complete the production of the workpiece.

Classification 4: Clamping Structure

Single-Cylinder/ Double-Cylinder/ Four-Cylinder Direct Pressure Injection Molding Machine

The direct pressure injection machine is also divided into different models such as single-cylinder, double-cylinder and four-cylinder according to the number of hydraulic cylinders. Because the single-cylinder type hydraulic cylinder has a large area, the production of parts will be more difficult, so there will be many problems when the single-cylinder model is used in a large machine. Accuracy is very important. Insufficient precision will directly affect the accuracy of mold clamping. At present, single-cylinder direct-pressure injection machines have been gradually replaced by multiple-cylinder direct-pressure injection machines. Double-cylinder injection represents two oil cylinders, which do the injection action in parallel. Usually, the injection speed of the double-cylinder will be slower than that of the single-cylinder under the same pressure, but the injection pressure will be increased. The template design of the four-cylinder direct pressure clamping is different, and the oil cylinder also has an automatic balance correction function, so it does not affect the accuracy of the clamping, and the scope of application is relatively wide. In the past, the most common problem of using the four-cylinder direct-pressure clamping model was the unbalanced force application, which resulted in damage to the mold and the size of the product could not meet the requirements. But most of this problem can be greatly improved as long as the components are processed accurately enough. Compared with the toggle type, the direct pressure type has the advantages of long life, direct mold clamping, no resistance during travel, so no need for frequent lubrication, and low maintenance costs. Although the machine is more expensive than the toggle type injection molding machine, the characteristics is more durable than that with the toggle type injection machine.

Toggle Type Injection Molding Machine

The characteristics of the toggle type injection machine are that it has the function of acceleration and deceleration, simple operation, lower operating cost and machine cost. The structure is also more complicated.

Composite Direct Pressure Injection Molding Machine

The components injected by the compound direct pressure injection machine are the same as the direct pressure type. The machine with a longer length has a larger mold opening force, and a longer clamping stroke can be designed. The durability of the components is a great challenge, and currently only a few manufacturers produce them in large quantities.

Classification Method 5: Injection Structure

Monochrome Injection Molding Machine (Single-Component Injection)

Monochromatic injection means that the entire plastic component is of the same color during injection. Monochromatic injection is the injection machine most people use at present. Monochromatic injection can also be used to inject products with two different colors. The color injection molding machine uses the first color to inject the first semi-finished product, and then uses the second color to process the semi-finished product to complete the production.

Multi-color Injection Molding Machine (Multi-Component Injection)

The multi-color injection machine can simultaneously inject plastic components with more than two different colors. At present, the most widely used multi-color injection molding machine is the two-color injection molding machine. It is an application in combination with LSR silicone rubber. In recent years, multi-color injection technology has gradually become a hot trend in the industry due to its environmental protection, high efficiency, good performance and other characteristics.

If you are worried about which injection molding machine should be used for the product you want to produce, you can first think about the characteristics of the product, the company's budget, use and longevity. Each type of injection molding machine has advantages and disadvantages. For example, if the company has a certain budget for energy expenditure, it can choose a type of injection molding machine that saves electricity. If there is a certain requirement for the precision of molding, it can also be given priority in quality aspect.