7 Injection Molding Machine Types and Their Advantages and Disadvantages

Injection molding machines are crucial for mass-producing high-precision parts across the automotive, electronics, medical devices, and consumer goods industries. As industry demands evolve, so does the technology behind these machines, offering diverse options tailored to specific production needs. This article will explore different machine types, advantages, and disadvantages.

Injection molding machines are fundamental in manufacturing various plastic products, each designed for specific purposes. Understanding the different types of injection molding machines—classified by power drive, clamping style, and injection molding materials—is essential for optimizing production processes and achieving the desired quality of products.

• Power Drive Classification：
  1. Hydraulic Injection Molding Machine: Powered by hydraulics.
  2. All-Electric Injection Molding Machine: Driven by servo motors.
  3. Hybrid/Servo Injection Molding Machin: Combining the best of hydraulic and all-electric machines.
• Clamping Style Classification：
  1. Vertical Injection Molding Machine: The machines operate vertically.
  2. Horizontal Injection Molding Machine: The machines operate horizontally.
     1. Toggle-Type Injection Molding Machine
     2. Two-Platen Injection Molding Machine
• Material Classification：
  1. Thermoplastic Injection Molding Machine: Designed for thermoplastics, which melt upon heating and solidify upon cooling.
     1. Single-Material (Single-Shot) Injection Molding Machine
     2. Multi-Material (Multi-Shot) Injection Molding Machine
  2. Thermoset Plastic Injection Molding Machine: Used for thermoset plastics, which undergo irreversible chemical changes upon heating.
     1. BMC Injection Molding Machine
     2. Rubber injection molding machine
  3. Powder Injection Molding Machine: Specialized machines for metal and ceramic powder injection molding.

Below, we explore 7 common injection molding machine types in detail, starting with hydraulic injection molding machines with their advantages and disadvantages.

Power drive classification in injection molding machines refers to the type of mechanism used to generate and control the power needed for the molding process. The three main types of power drives are hydraulic, electric, and hybrid. Each type has distinct advantages and disadvantages regarding energy efficiency, precision, maintenance, and cost.

Hydraulic Injection Molding Machines

Hydraulic injection molding machines, the most traditional type, have been used for decades. They utilize hydraulic cylinders to control machine components' movement. They utilize hydraulic cylinders to inject molten material into molds, offering consistent pressure and excellent control over molding.

Advantages

Hydraulic machines are famous for their durability and ability to handle various materials.

1. Lower Initial Cost: Hydraulic injection molding machines have a lower initial cost compared to electric and hybrid models, making them attractive for manufacturers looking to minimize upfront expenses.
2. Cheaper Replacement Parts: Hydraulic machines have cost-effective and easily obtainable replacement parts, reducing maintenance downtime.
3. Durability and Strength: The hydraulic components of these machines are designed to last, offering exceptional resistance to wear and tear, contributing to their longevity and reliability in production environments.
4. Powerful Clamping Force: Hydraulic machines require high clamping force to mold large or complex parts accurately and maintain product integrity.
5. Simplicity and Ease of Use: Hydraulic injection molding machines are simple to operate and maintain, with a design that enhances reliability and reduces the risk of mechanical failures.

Disadvantages

Hydraulic injection molding machines, while versatile and powerful, come with several disadvantages that may impact efficiency and operational costs:

1. Warm-Up Time: Hydraulic machines require a warm-up period to reach optimal operating conditions, which can delay production and reduce overall efficiency.
2. High Power Consumption: The machine's energy consumption is higher than that of all-electric machines, resulting in higher energy consumption costs and environmental impact.
3. Limited Precision Control: Compared to electric machines, hydraulic systems offer less precise control, making them less suitable for applications that require fine-tuned accuracy.

Electric Injection Molding Machines

Electric injection molding machines are gaining popularity due to their energy efficiency and precision. These machines are powered by electric servo motors, making them ideal for high accuracy applications.

Advantages

Electric machines are more energy efficient, offer faster cycle times, quieter operation, and better repeatability than hydraulic machines, making them ideal for high-precision parts.

1. Energy Efficiency: Electric injection molding machines are highly energy efficient, as they only consume power when in operation and the motor output is matched to the load requirements, minimizing energy wastage.
2. Faster and Repeatable Processes: Electric machines are digitally controlled, ensuring highly repeatable processes with minimal supervision for enhanced production speed and consistency.
3. Clean Operation: The lack of oil in electric machines makes them perfect for cleanroom environments needed for producing medical and food packaging products.
4. High Precision and Reproducibility: Electric machines provide precise control over injection parameters such as pressure and speed, ensuring consistent and accurate production.
5. Quiet and Eco-Friendly: Electric machines operate quietly and produce less noise pollution than hydraulic machines, contributing to a more comfortable and environmentally friendly workplace.

Disadvantages

Despite their numerous benefits, all-electric injection molding machines also present certain challenges and limitations:

1. Higher Initial Costs: The upfront cost of an all-electric injection molding machine is usually higher than that of a traditional hydraulic machine due to expensive high-precision servo motors and advanced control systems. The price of imported electric machines maybe 2-4 times higher than that of hydraulic machines, leading to a higher hourly production rate.
2. Clamping Force Limitations: All-electric machines may not be as effective as hydraulic presses for molding extremely large parts. 
3. Maintenance and Technical Expertise: Maintaining all-electric machines requires specialized technical knowledge due to their complex electronic control systems. It involves intricate maintenance and troubleshooting processes compared to hydraulic presses. Additionally, components like ball screws are more sensitive to wear and tear, requiring proper upkeep to prevent damage.
4. Electricity Dependence: All-electric machines are energy-efficient but depend on a stable power supply. In areas with unreliable electricity, this can cause production issues.

Hybrid/Servo Injection Molding Machines

Hybrid injection molding machines combine the best features of hydraulic and electric machines. They use a combination of electric servo motors and hydraulic power to optimize performance.

Advantages

1. Versatile Design: Hybrid injection molding machines combine the best features of hydraulic and electric machines, offering flexibility for greater customization and adaptability in various applications.
2. Balanced Performance: Hybrids combine the energy efficiency and precision of electric machines with the force-generating capacity of hydraulic units for versatile molding processes.
3. Efficient Motor Operation: Hybrid machines use servo drives instead of fixed-speed pump motors, allowing the pump to operate only when needed to optimize oil usage and improve process efficiency.
4. Balance Cost: Hybrid machines are a cost-effective alternative, popular in industries like medical device manufacturing, where precision and reliability are crucial.
5. Energy-Efficient and Eco-Friendly: Hybrid machines operate at lower temperatures using a closed-loop process, reducing energy consumption and environmental impact. They also offer exceptional clamping force and high-precision production, accommodating various part designs, including those with thick and thin walls.

Disadvantages

Although servo machines are efficient, they are still more expensive than hydraulic machines. Additionally, the performance of the servo motors used with different servo machines can vary greatly, so choosing the right injection machine manufacturer is crucial.

Related product: Servo machine – HRS series

The clamping style in injection molding refers to how the machine's mold halves are held together during the injection molding process. The main clamping styles are vertical and horizontal, with variations like toggle and two-platen systems.

Vertical Injection Molding Machines

Vertical injection molding machines differ from the traditional horizontal injection molding machines in that they inject material into the mold from above. These machines are particularly useful for insert molding and overmolding applications.

Advantages

Vertical machines are well-suited for complex inserts and overmolding, enabling easy insert placement and boosting production efficiency.

Disadvantages

Vertical machines have lower output rates than horizontal machines, making them less suitable for high-volume production.

Further reading: Comprehensive Guide to Vertical Injection Molding Machines

Toggle-Type Injection Molding Machines

Toggle-type injection molding machines utilize a toggle system to apply clamping force to the mold. There are two types of toggles.

• Toggle-Type：
  1. Inward Toggle: The general toggle machine type that toggle linkage compresses inward during clamping. 
  2. Outward Toggle: The toggle linkage expands outward during the clamping process, allowing for the production of small and medium-sized deep barrel-shaped plastic products.

Advantages

The toggle mechanism ensures consistent clamping force, making it ideal for complex part production. These machines are also generally more affordable, offering a cost-effective choice for many manufacturers.

Related product: Inward-toggle machine – HRN series

Related product: Outward-toggle machine – NRV series

Two-Platen Injection Molding Machines

Two-platen injection molding machines are designed to accommodate large molds with less overall machine length. This design reduces the machine's footprint and increases its efficiency in producing large parts.

Advantages

These machines are well-suited for large part injection molding. The two-platen design provides high clamping force with a compact footprint, making them ideal for manufacturing large automotive or industrial components.

Further reading: 2 Platen Injection Molding Machine vs 3 Platen

Related product: Twp platen machine – NRH series

Material classification in injection molding refers to the types of plastics that the machine can process, primarily divided into thermoplastics and thermosets. Thermoplastics can be melted and re-molded multiple times, while thermosets solidify irreversibly when heated.

• Thermoplastic Injection Molding Machines
  1. Advantages: Versatility in material use and reusability of material scraps.
  2. Disadvantages: Requires precision in temperature control and is limited to thermoplastics.
• Thermoset Injection Molding Machines
  1. Advantages: Suitable for high-heat, durable, and non-meltable application products
  2. Disadvantages: Irreversible chemical process and higher waste if not carefully managed 

Multi-Material Injection Molding Machines

Multi-material injection molding machines are designed to handle components made from two or more different materials. These machines enable the production of complex, multi-material parts in a single cycle.

Advantages

These machines enable the production of complex parts with multiple materials, reducing assembly time and improving product quality. They are particularly useful in industries like automotive and consumer electronics, where multi-material components are common.

Related product: Double-shot machine – HDC series

Related product: Tri-shot machine – HTC series

Today's most commonly used injection molding machines are horizontal-type servo-driven hydraulic injection molding machines. These machines have a combination of reliability, precision, and cost-effectiveness. The servo-driven hydraulic system offers superior energy efficiency compared to older fixed-speed motor designs, while still providing the robust clamping force required for large-scale production.

Further reading: Choosing the Right Injection Molding Machine: A Comprehensive Guide

Choosing the appropriate injection molding machine depends on your manufacturing requirements. Hydraulic machines provide power and flexibility, electric machines offer energy efficiency and precision, and servo machines combine both advantages. Vertical and horizontal machines are suitable for different spatial and production needs, while multi-material machines allow for the creation of intricate, multi-functional parts. 

If you are searching for machines, please contact Huarong, an experienced injection molding machine manufacturer to provide expert guidance and support to help you achieve your needs.

• Group Name: Huarong Group
• Brand: Huarong, Yuhdak, Nanrong
• Service Offerings: Injection Molding Machine, Vertical Injection Molding Machine, Injection Molding Automation
• Tel: +886-6-7956777
• Address: No.21-6, Zhongzhou, Chin An Vil., Xigang Dist., Tainan City 72351, Taiwan
• Official Website: https://www.huarong.com.tw/

Previous news : Celebrating Innovation and Excellence: Huarong at TaipeiPlas 2024

Next news: Case Study: Elevating Product Packaging with In-Mold Labeling (IML) Technology