Injection Moulding Machine

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An Overview on Injection Moulding Process

Injection molding is a highly versatile and efficient manufacturing process used to create a wide variety of products and components. It involves the use of molds, which are usually made of steel or aluminum, to form the desired shape of the product. These molds are precision-engineered to ensure accuracy and consistency in the final output.

The process starts with raw materials, typically synthetic resins in the form of small pellets or granules. These materials are loaded into a hopper and fed into a heated barrel. Inside the barrel, the pellets are heated to a molten state, becoming a viscous fluid that can easily flow into the mold cavities. Once the material is sufficiently melted, a screw-like plunger pushes it forward into the mold through a nozzle. The mold consists of two halves, an injection side, and an ejection side. The molten material fills the empty space inside the mold, taking the shape of the cavity and any additional features or details in the mold design.

After the mold is filled, the material is allowed to cool and solidify, which typically happens quickly due to the high thermal conductivity of the mold material. Once the material has hardened, the mold is opened, and the finished product is ejected. Often, the mold may have multiple cavities, allowing the production of several parts simultaneously in each molding cycle, which enhances the production efficiency. Injection molding offers several advantages over other manufacturing methods. It can produce complex shapes with high precision and repeatability. This makes it an ideal choice for mass production of items like automotive parts, electronic components, medical devices, household goods, and more.

Moreover, the process is highly automated, which leads to reduced labour costs and faster production rates. This makes it suitable for large-scale manufacturing, where high volumes of identical parts are required. However, setting up the injection molding process can be expensive as it requires designing and manufacturing the molds, which can be time-consuming. Nevertheless, once the molds are ready, the cost per part becomes relatively low, making it economically viable for mass production of injection moulding products.

What is Injection Moulding Machine?

An injection molding machine is a specialized manufacturing device used to produce various plastic products and components through the injection molding process. It consists of two main parts: the injection unit and the clamping unit. 

The injection unit is responsible for melting the plastic pellets or granules and then injecting the molten material into the mold. It comprises a hopper to hold the raw plastic material, a heating barrel to melt the material, and a screw or plunger to push the molten plastic into the mold cavity. The clamping unit is designed to securely hold the mold in place and provide the necessary force for the mould’s closing and clamping actions. It ensures that the molten plastic remains in the mold until it cools and solidifies, taking the desired shape.

Injection molding machines are known for their fast processing speed and cost-effectiveness, making them suitable for high-volume production. There are different types of injection molding machines, including motorized machines driven by servo motors, hydraulic machines powered by hydraulic motors, and hybrid machines that use a combination of servo and hydraulic motors.

In recent years, computer numerical control (CNC) technology has been integrated into injection molding machines, allowing for high-speed and precise injection under programmed control. This advancement has contributed to the popularity of models capable of producing complex and detailed products with greater efficiency.

Working Principle of Injection Moulding Machine

The injection moulding machine process involves several sequential steps to produce plastic products and components.
The process begins with the preparation of the raw material, usually in the form of plastic pellets or granules. These pellets are loaded into the machine’s hopper.

  1. Injection Phase: The injection molding process starts with the injection phase. The plastic pellets are fed from the hopper into the heating barrel of the machine. Inside the barrel, the pellets are heated and gradually melt into a molten state, becoming a viscous fluid.
    The molten plastic is then forced forward by a screw or plunger within the barrel, which creates pressure. The screw or plunger acts as a piston, pushing the molten plastic through a nozzle and into the mould’s cavity. The mold is a carefully designed hollow space that represents the shape and features of the desired product.
  2. Cooling and Solidification: Once the mold cavity is filled with the molten plastic, the cooling and solidification phase begins. The mold is equipped with cooling channels through which water or another cooling agent circulates to rapidly cool the molten plastic. Cooling is a critical step as it determines the final properties and quality of the product.
    As the plastic cools down, it solidifies and takes the shape of the mold cavity. The cooling time can vary depending on the thickness and complexity of the product. Once the plastic has solidified, the mold remains closed during the cooling period.
  3. Ejection: After the cooling and solidification phase, the mold is opened, and the finished product is ejected from the mold cavity. Ejection is typically achieved by ejector pins or plates that push the product out of the mold.
  4. Clamping and Reset: Once the product is ejected, the mold is closed again in preparation for the next cycle. This clamping phase ensures that the mold is tightly shut to start a new injection cycle. The clamping unit of the machine provides the force required to keep the mold closed during injection and cooling.
  5. Repeat Cycle: The process described above is a continuous cycle, and the injection molding machine can repeat these steps to produce multiple products in a rapid and automated manner. The cycle time varies depending on factors such as the size of the product, the material used, and the complexity of the mold.

Overall, the injection molding machine’s working principle involves melting and injecting plastic into a mold cavity, cooling and solidifying the plastic, ejecting the finished product, and then resetting the machine for the next cycle. This process allows for efficient and high-volume production of various plastic products used in different industries.

Types of Injection Moulding Machine

Method 1: Power Drive

  1. Hydraulic Injection Molding Machines: Hydraulic injection machines are powered by hydraulics, offering high efficiency. However, they require continuous operation to maintain a constant temperature for the melted plastic. Start-up and shutdown procedures need special attention to avoid damage. During start-up, plastic not at the proper temperature must be discarded for recycling. Shutdown may require removing unwanted resin to prevent clogging during start-up.
  2. All-Electric Injection Molding Machines: All-electric machines are pricier but do not require continuous operation or temperature adjustments. They provide stable and efficient injection molding, without the risk of hydraulic leaks.
  3. Hybrid/Servo Hybrid Injection Molding Machines: Hybrid machines combine hydraulic and all-electric advantages. They are cost-effective and energy-efficient, offering higher injection and clamping pressures than all-electric types.

Method 2: Operating Direction

  1. Vertical Injection Molding Machines: Operate in a vertical position and are suitable for manufacturing small parts, saving space. Often combined with a rotary table or conveyor belt for improved production efficiency.
  2. Horizontal Injection Molding Machines: The most widely used injection machines, featuring low body height, fast molding, and easy operation and maintenance.

Method 3: Applicable Raw Materials

  1. Thermoplastic Injection Molding Machines: Used for thermoplastics like PE, PP, ABS, TPU, etc. The plastic pellets are heated and injected into molds, solidifying upon cooling.
  2. Thermoset Plastic Injection Molding Machines: Used for thermosetting plastics like FRP and Melamine. The plastic undergoes irreversible solidification upon heating, making recycling challenging.
  3. Powder Injection Molding Machines: Utilized for “metal injection molding” (MIM) or “ceramic injection molding” (CIM). Precision-treated metal or ceramic powders and bonding materials are used to produce small, high-precision parts.

Method 4: Clamping Structure

  1. Single-Cylinder/Double-Cylinder/Four-Cylinder Direct Pressure Injection Molding Machines: Differentiated by the number of hydraulic cylinders operating them. Multiple-cylinder direct-pressure machines offer better control and accuracy, while four-cylinder machines provide automatic balance correction during clamping.
  2. Toggle Type Injection Molding Machines: Feature a mechanical device with two bars connected by a pivoting toggle to amplify force. These machines have a simple operation and lower operating costs.

Method 5: Injection Structure

  1. Monochrome Injection Molding Machines (Single-Component Injection): Inject a single color for the entire plastic component or products with two different colours using sequential injection.
  2. Multi-color Injection Molding Machines (Multi-Component Injection): Simultaneously inject plastic components with two or more different colours, popular for its environmental friendliness, efficiency, and performance.

Main Components of Injection Molding Machine

The main components of an injection molding machine are:
  1. Injection Unit: This unit is responsible for melting and injecting the plastic material into the mold. It comprises three main components:
    • Screw Motor Drive: The screw motor drive controls the movement of the screw, which helps in feeding and melting the plastic pellets.
    • Reciprocating Screw and Barrel: The reciprocating screw and barrel work together to transport, melt, and homogenize the plastic material before injection.
    • Heaters, Thermocouple, Ring Plunger: The heaters are used to heat the barrel, maintaining the required temperature for melting the plastic. The thermocouple monitors the temperature, and the ring plunger helps push the melted plastic into the mold.
  2. Clamping Unit: This unit is responsible for holding the mold in place and exerting the required force during the injection process. It comprises three main components:
    • Mold: The mold is a hollow cavity in which the molten plastic is injected and takes the desired shape to form the final product.
    • Clamping Motor Drive: The clamping motor drive controls the movement of the clamping mechanism, ensuring the mold remains closed during injection.
    • Tie Bars: The tie bars are sturdy metal rods that hold the two halves of the mold together and keep it securely clamped during the injection process. These tie bars are fixed into the edge of a workbench.
    These main components work together to carry out the injection molding process effectively and produce various plastic products with precision and consistency.

Injection Moulding Machines offered by Pratishna Engineers

Pratishna Engineers offers a range of Injection Moulding Machines designed to meet various industrial needs. Here’s a brief overview of the different moulding machine types:

Which Plastics are used in Injection Moulding?

Injection molding offers a vast array of plastic material options, with over 85,000 commercial choices and 45 polymer families available for use. These plastics can be broadly categorized into two groups: thermosets and thermoplastics.

Some of the commonly used plastics in injection molding include:

  1. Polycarbonate (PC): Known for its strength and impact resistance, PC exhibits low shrinkage and good dimensional stability. Transparent grades of PC are available, offering a high cosmetic finish and good heat resistance.
  2. High-Density Polyethylene (HDPE) and Low-Density Polyethylene (LDPE): HDPE and LDPE are popular choices due to their high ductility, good tensile strength, strong impact resistance, resistance to moisture absorption, and recyclability.
  3. Acrylonitrile Butadiene Styrene (ABS): A tough and impact-resistant plastic, ABS finds widespread use in various industries. It offers good resistance to acids and bases, low shrinkage rates, and high dimensional stability.
  4. Aliphatic Polyamides (PPA) or Nylons: Nylons come in different types, each with its own advantages. Generally, nylons offer high strength and temperature resistance, as well as chemical resistance (except against strong acids and bases). Some nylons also provide abrasion resistance, hardness, stiffness, and good impact strength.
  5. Polymethyl Methacrylate (PMMA) or Acrylic: PMMA offers good optical properties, high gloss, scratch resistance, low shrinkage, and reduced sink for geometries with varying sections.
  6. Polypropylene (PP): An economical resin, PP delivers high impact resistance in certain grades. Copolymers provide greater impact resistance, and PP is also wear-resistant, flexible, and can exhibit high elongation. It is resistant to acids and bases.
  7. Polyoxymethylene (POM) or Acetal: POM is characterized by high hardness, stiffness, strength, and toughness. It is resistant to hydrocarbons and organic solvents, with good lubricity and elasticity for specific applications.
  8. Polybutylene Terephthalate (PBT): PBT is known for its good electrical properties, making it ideal for power components and automotive applications. It comes in various grades, with some being tough and flexible. PBT is also resistant to fuels, oils, fats, and many solvents.
  9. Polyphenylsulfone (PPSU): PPSU offers dimensional stability, high toughness, temperature and heat resistance, along with resistance to radiation sterilization, alkalis, and weak acids.
  10. Polyether Ether Ketone (PEEK): PEEK is a high-performance resin with exceptional heat resistance, flame retardancy, strength, dimensional stability, and chemical resistance.
  11. Polyetherimide (PEI) or Ultem: PEI provides high temperature resistance, flame retardancy, strength, dimensional stability, and chemical resistance.

These are just a few examples of the wide range of plastics used in injection molding, each chosen for its specific properties and suitability for different applications.

Advantages of Injection Moulding Machine

Injection molding machines offer several advantages, making them a popular choice for manufacturing plastic products:

High Production Rate

Injection molding machines can produce a large number of parts in a short period, meeting high demand and reducing lead times.

1

High Efficiency

  1. Injection molding machines can produce a large number of identical parts quickly and consistently, making them highly efficient for mass production.
2

Versatility

Injection molding machines can process a wide range of plastic materials, allowing the production of diverse products with different properties and characteristics.

3

Low Labour Costs

Once the machine is set up and running, minimal manual labour is required, reducing production costs and improving productivity.

4

Reduced Material Waste

Injection molding minimizes material waste as any excess plastic can be recycled and reused in the manufacturing process.

5

Complex Shapes and Design Flexibility

The process enables the creation of intricate and complex shapes that may be challenging or impossible to achieve with other manufacturing methods.

6

Precision and Consistency

These machines ensure high accuracy and repeatability, resulting in consistent and uniform products with tight tolerances.

7

Surface Finish and Detail

The process produces smooth and detailed surfaces on the moulded parts, reducing the need for additional finishing or polishing.

8

Low Scrap Rates

The precise control of the injection process helps minimize scrap rates, leading to cost savings and better resource utilization.

9

Environmentally Friendly

Injection molding generates less waste compared to other manufacturing processes, and with the use of recyclable materials, it can be an eco-friendly option.

10

Automation and Integration

Injection molding machines can be integrated into automated production lines, streamlining the manufacturing process and improving overall efficiency.

11

Cost-Effective for Large Runs

For large production runs, the cost per part decreases significantly, making injection molding economically viable.

12

Overall, the advantages of injection molding machines make them an essential tool for various industries seeking efficient, cost-effective, and reliable plastic product manufacturing.

Key Considerations for Purchasing an Injection Molding Machine

Before proceeding with injection molding, it is crucial to consider the following factors:

  1. Production Quantity: The number of parts you intend to manufacture plays a crucial role in determining the cost-effectiveness of injection molding. It is important to analyse whether the volume of production justifies the initial investment.
  2. Financial Considerations: Injection molding requires significant upfront investment in machinery and molds. The cost of setting up the manufacturing process can be high, so careful financial planning is essential.
  3. Production Considerations: Reducing cycle times through optimization, using hot runner molds, and well-designed tooling can significantly improve production efficiency. These small changes can lead to cost savings, especially when producing large quantities of parts. Minimizing assembly requirements also reduces production costs, particularly for high-volume production runs.
  4. Design Factors: Simplifying the design and reducing the number of parts can make the injection molding process more efficient. Complex designs may lead to longer cycle times and higher production costs. Additionally, the design of the mold is crucial to ensure defect-free production.

By taking these considerations into account, businesses can make informed decisions about the feasibility and cost-effectiveness of using injection molding for their manufacturing needs. Proper planning and optimization of the injection molding process can lead to significant cost savings and improved overall production efficiency.

Injection Moulding Machine Applications

Injection molding machines are widely used across various industries for a multitude of applications due to their versatility, efficiency, and precision. Some common applications of injection molding machines include:

  1. Industrial Equipment: Injection molding is employed to produce a wide range of industrial equipment parts, including machinery components, gears, and housings.
  2. Consumer Products: Injection molding machines are used to manufacture a wide range of consumer products, including plastic bottles, containers, caps, and closures, household appliances, kitchenware, and toys.
  3. Medical Devices: Injection molding is essential for producing medical devices like syringes, IV components, medical tubing, inhalers, and various surgical instruments with high precision and cleanliness.
  4. Electronics: The electronics industry relies on injection molding for the production of items such as phone cases, connectors, computer components, and power adapters.
  5. Automotive Parts: Many components in the automotive industry are produced using injection molding machines, such as bumpers, dashboards, interior trims, door panels, and various under-the-hood parts.
  6. Packaging: Injection molding machines play a significant role in producing packaging materials, including thin-wall containers, food packaging, and closures for bottles and jars.
  7. Construction: In the construction industry, injection molding is used to create various plastic components such as pipes, fittings, roofing materials, and insulation products.
  8. Sports Equipment: Many sports equipment items, such as helmets, protective gear, and grips, are produced using injection molding.
  9. Aerospace: Injection molding is used in aerospace for manufacturing parts with specific requirements like lightweight, high-strength materials, and intricate geometries.
  10. Agriculture: Injection molding machines are utilized in the agricultural sector to manufacture irrigation components, greenhouse parts, and agricultural equipment.

These are just a few examples of the extensive applications of injection molding machines across diverse industries, demonstrating their vital role in modern manufacturing processes.

Why Choose Us?

Pratishna Engineers stands out as the leading injection moulding machine manufacturers in India. Our primary focus is on ensuring the satisfaction and happiness of our buyers, as we believe that it brings manifold benefits to any company. We have streamlined the payment process, offering convenient options both offline and online. With a strong commitment to essential business values such as integrity, trustworthiness, and loyalty, we treat each customer and employee with utmost respect. Our machines are designed to cater to the diverse preferences of consumers across various market segments, showcasing exceptional performance and capability. If you are seeking a distributorship opportunity for injection molding machines with a renowned and reliable company, Pratishna Engineers, please feel free to contact us

FAQs

Back Pressure in an injection molding process is often defined as “the resistance of the screw to recover as the metering section pumps molten plastic through the non-return valve to the front of the screw.” The pressure that is built up in front of the screw forces the screw back to the desired set-point.

The right size and capacity of an injection molding machine depend on factors like the size and complexity of the parts to be produced, the required production rate, and the type of plastic material used.

Clamping force is crucial for holding the mold closed during injection. It is determined based on the projected area of the part and the required safety factor.

Safety features may include safety guards, emergency stop buttons, interlocks, and safety sensors to prevent accidents during operation.

Yes, injection molding machines can be integrated into automated production lines, leading to increased productivity, reduced labour costs, and improved efficiency.

Regular maintenance and proper care, such as cleaning, lubrication, and timely replacement of wear parts, can extend the machine’s lifespan and ensure optimal performance.

Lead times and delivery schedules depend on factors like the machine’s configuration and current demand. It’s best to inquire directly for specific details with Pratishna Engineers, a leading injection moulding machine manufacturers in India.

Yes, Pratishna Engineers offer customization options to tailor the machine to specific production requirements.

Pratishna Engineers typically offer technical support, training, and after-sales service to ensure smooth operation and customer satisfaction.

Pratishna Engineers offer training programs and resources to educate operators on proper machine operation, maintenance, and safety protocols.

Energy consumption and operating costs depend on factors like machine type, production volume, and energy efficiency. All-electric and hybrid machines are generally more energy-efficient compared to hydraulic machines.

Market Area of Pratishna Engineers

Pratishna Engineers Ltd is a prominent company in India that specializes in manufacturing, supplying, and exporting Injection Moulding Machines. We cater to a wide range of customers across various industries and are dedicated to ensuring their satisfaction by offering competitive market prices. Our products are manufactured, supplied, and marketed to cities all over India, and we also export to Europe, the Middle East, and Africa: –

Pratishna Engineers Supplying to these Indian Cities: –
Ahmedabad | Indore | Pune | Ludhiana | Surat | Delhi | Kolkata | Noida | Mumbai | Chennai | Jaipur | Gurugram | Hyderabad | Bangalore | Vadodara | Faridabad | Rajkot 

Pratishna Engineers Exporting to these Countries: –
Netherlands | Mexico | Kenya | Tanzania | Oman | USA | Poland | Italy | Nigeria | Indonesia | United Kingdom | Malaysia | Sri Lanka | Australia | Qatar | Spain | Canada | Uganda | Maldives | Saudi Arabia | United Arab Emirates | Germany | Djibouti | Mauritius