Injection Molding Machines (All You Need To Know)

Types of Injection Molding Machines

Injection molding machines produce high-volume parts. But they can't produce those parts without auxiliary equipment. For example, large-scale deliveries require specialized unloading systems. These systems move the resin over long distances (up to 1,000 feet) and lift it high enough to fill a silo. Cycling loaders can push bulk material over shorter distances and move smaller loads.

Definition of molding machine

Injection molding machines are widely used in the manufacturing of plastic products. These machines are controlled by varying the pressure in the press to control the amount of molten plastic that flows out of the nozzle.

The process is very repeatable and produces high volumes of finished products, resulting in less wastage and better consistency. Injection molding machines also make it possible to create plastic parts with multiple features, such as a wide range of shapes.

To achieve an accurate color, a material must be tested for shore hardness. A stereoscope is used for this test. It uses a conical hammer with a diamond point to strike the material under test. The degree of rebound is noted on a graduated scale; the higher the number, the harder the material.

The yield of a molding process is the amount of material produced from one mold cycle, including the cull, runner, and flash. The machine's shot capacity refers to the maximum weight that a workpiece can hold.

Plunger Injection Molding Machine

Initially introduced by Interplas in 1961, the plunger-type injection molding machine was an innovation in the thermosetting polyester molding compound industry. This type of machine has since gained popularity in the plastics industry.

Prior to the advent of plunger-type machines, compression and transfer types dominated the market. Today, however, the plunger-type injection molding machine is the most popular type of plastic injection machine. This article looks at its various advantages and disadvantages.

The Plunger Injection Molding Machine has two main parts. The first part is a plunger and is located at any axial position of the machine barrel. The second part is a cylinder with a screw at its end. The material being injected is forced out of the machine barrel via a gap. The resulting part is shaped into the desired shape. The Plunger Type Injection Molding Machine can produce a variety of plastic products, including toys and other consumer items.

Screw Plunger Injection Molding

A screw plunger injection molding machine is an alternative to the more common and commonplace plunger-type machines. Screw-type machines work by forcing plastic material into a mold by means of direct fluid pressure. The pressure from the ram drives the moving platen while the clamping unit holds the mold closed during the injection. It is used to create intricate parts such as car bumpers, automobile parts, and more.

This system consists of a feeding device, a cylinder, and a screw that moves back and forth in the injection mold. The feeding device and the screw work together to move the material into the mold. This simple structure provides consistent plasticizing, making the entire process more efficient. Here are some characteristics of the screw-type injection molding machine:

The screw-type injection molding machine has two chambers, one to plasticize raw material and the other to inject it into the mold. The plasticizing chamber is located in the upper section of the machine. The plasticized material is then sent through the diverter shuttle into the injection chamber. This process begins with the injection of the material into the mold cavity. The plastic material is then conveyed back and forth between the two chambers, creating the desired part.

Plunger-Plunger Injection Molding

The gearbox 22 and injection cylinder 11 of Plunger-Plunger Type Injector Molding machines are mechanically interconnected. The gearbox contains a straight-through passage 59 and a plug 60 that prevents material from flowing backward during injection and check head operation. A piston or pump drives the material into the mold during the injection. The injection takes place as the machine rotates.

The screw-plunger coaxial-type injection molding machine overcomes the problems of prior art by its simple design and operation. The axial temperature difference between the injection and clamping cylinders is low, thereby ensuring that the material precursor is the first to come out of the mold cavity. A screw-type Injection Molding machine consists of a reciprocating screw and barrel assembly, injection nozzle, and hopper.

Plunger-Plunger Type Injector machines are similar to screw-type Injection Molding machines. They do the same thing, except that plunger-type injection machines do not contain a screw in the plasticizing chamber.

Whether a machine uses a screw or plunger-plunger injection system, both are effective for producing plastic parts. So, which one is the better option?

Reciprocating Injection Molding

A Reciprocating Screw Injection Molding machine is a type of plastic injection molding machine. It is a horizontal extruder that uses a screw to move plastic material forward through a barrel.

The plastic material transforms from granular to molten as the screw rotates. The screw backs up to a limit switch that controls the amount of material in the barrel and moves forward to displace the material. In this way, the screw functions as a ram and a plunger.

The reciprocating screw injection molding machine offers several advantages. It plasticizes heat-sensitive materials more efficiently. It also blends colors more quickly, since the screw has a mixing cation.

This means that a plastic object produced on a reciprocating screw machine will have a better color consistency than a plastic part made on a traditional injection molding machine. Listed below are some benefits of using a Reciprocating Screw Injection Molding Machine.


There are many advantages to hydraulic injection molding machines. Injection molding is usually done with high pressure to create precision parts, and these machines are capable of holding parts weighing as much as 50 pounds.

The clamping force of these machines is usually 3 to 4 tons per square inch. However, this technology is still evolving and some machines can hold parts as heavy as 500 pounds. If you're considering purchasing a hydraulic injection molding machine, you should read up on these advantages.

A hydraulic machine will be less expensive than a comparable electric machine. The hydraulic machine's smaller footprint means it will use up to ten to twenty percent less floor space. This machine also delivers the highest part productivity and quality, which increases the overall profitability of the operation. In addition, the machine's integrated thermal control systems help keep the machine's operating temperature within the 110 to 120-degree range. The benefits of hydraulic injection molding machines are well worth considering for any production-level molder.


Injection molding machines are critical parts of production processes. If these machines fail to work properly, they can lead to increased maintenance costs, lower quality products, and delays in master production scheduling.

Maintenance regulations are established for these machines, and they are inspected on a regular basis. The production company finds some developments in this area helpful for making decisions. Here is an example of a breakdown of maintenance processes:

The main process involves applying pressure to the mold material to produce a molded part. Injection pressure generally ranges from 100 to 150 MPa. Pressure is applied continuously for a period of time after the injection process. Some force is required to lock the molded part in its final position.

This process is referred to as 'hot-shot molding.' Some processes are prone to contamination or malfunction. These factors should be taken into account before investing in an injection molding machine.

In addition to manufacturing plastic injection molding machines, Windsor is also a leading supplier of plastics processing machinery. Its factory covers an area of 100,000 square meters, employs more than 1750 workers, and exports its products worldwide. Apart from this, the company also offers OEM and OBM services. The company also exports its products to numerous regions worldwide, including Russia, Brazil, and India. When you are looking for a supplier of industrial injection molding machines, consider a company in China, which was founded in 1986.


The clamping unit of an Electric Injection Molding Machine is responsible for holding the mold closed during the process of molding plastic. These clamps are either hydraulically or electrically driven.

They ensure that no plastic escapes the mold when the injection occurs. When selecting a clamping unit, make sure that the machine has a clamping force that will keep the mold closed. The clamping force of an Electric Injection Molding Machine will be based on the clamping force needed to produce a specific plastic part.

The hydraulic-operated injection molding machines are noisy and lack the precision of an electric machine.

However, the electric-operated machines use less energy and can run unattended throughout production. Electric-operated machines are also quieter than their hydraulic counterparts. Additionally, they require less maintenance and capital investment.

These advantages make them the more popular option for many businesses. Electric machines are also more energy-efficient than their hydraulic counterparts, saving up to 70% on electricity costs.

 Injection molding machines can be classified by the type of plunger that forces the material into the die. The three types are plunger type, screw plunger, and plunger-plunge. Screw plungers are further subdivided into the reciprocating screw and rotating screw. Which type of injection molding machine do you think would work best for your needs?

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