The plastic injection molding industry has developed for more than a century, and during this long evolution, injection molding machines have become more efficient, precise, and reliable. Today, when manufacturers plan new production lines or upgrade existing equipment, one question is asked again and again: should you choose an electric or a hydraulic injection molding machine?
To make a sound decision, it is important to understand how these two machine types work, how they differ in performance and cost, and which applications they are best suited for. This article provides a clear and practical comparison to help manufacturers select the right solution for their production needs.
Before comparing performance, it is necessary to understand how each machine operates, as the working principle directly affects efficiency, precision, and operating cost.
To begin with, hydraulic injection molding machines rely on hydraulic oil to generate force and movement. A hydraulic pump draws oil from a reservoir and sends it through valves and pipelines under high pressure. This pressure drives hydraulic cylinders that control key actions such as injection, clamping, mold opening, and ejection.
Because hydraulic systems can generate strong and stable force, they have long been used in injection molding, especially for applications requiring high clamping force or large molds. As a result, hydraulic injection molding machines remain widely used across many industries.
In contrast, electric injection molding machines use servo motors instead of hydraulic oil. Each major function—such as injection, screw rotation, clamping, and ejection—is controlled by its own electric motor. These motors convert electrical energy directly into mechanical motion.
Thanks to digital control systems, electric machines can precisely control speed, position, and pressure. As a result, they offer highly accurate and repeatable performance, which is especially important for precision plastic parts.
Once the basic principles are clear, the next step is to compare real-world performance factors that matter most in daily production.
First of all, energy efficiency is one of the biggest differences between the two machine types. Hydraulic injection molding machines typically consume energy continuously, even when the machine is idle, because the hydraulic pump often runs non-stop.
Electric injection molding machines, on the other hand, consume energy only when motion is required. Servo motors operate on demand, which significantly reduces wasted power. In practical production environments, this difference leads to much lower energy consumption for electric machines, making them attractive for factories aiming to reduce operating costs.
Equally important, precision plays a key role in product quality. Electric injection molding machines offer excellent control over injection speed, position, and pressure. This allows for consistent shot size and stable part quality over long production runs.
Hydraulic machines can also achieve good precision, but the nature of oil flow, temperature variation, and valve response makes fine control more challenging. Therefore, for products with tight tolerances, electric machines generally provide better repeatability.
When it comes to production speed, electric machines again show clear advantages. Servo motors respond faster than hydraulic systems, which improves injection speed and shortens cycle time. This is especially valuable in high-speed applications such as cap production or thin-wall parts.
Hydraulic machines, while reliable, usually have slower response times due to oil compression and system inertia. As a result, cycle times are often longer.
Another practical consideration is the working environment. Hydraulic injection molding machines generate more noise due to pumps and oil flow. There is also a risk of oil leakage, which can affect cleanliness.
Electric machines operate more quietly and do not use hydraulic oil. This creates a cleaner and more comfortable factory environment, which is particularly important in medical, electronics, and food-related applications.
Beyond performance, maintenance and long-term cost strongly influence purchasing decisions.
Hydraulic machines require regular maintenance, including oil replacement, filter changes, and leak inspection. Over time, seals and valves may wear out, leading to downtime.
In contrast, electric injection molding machines have fewer consumable parts. Without oil, pumps, or filters, maintenance needs are lower, and machine uptime is generally higher.
Although hydraulic machines often have a lower initial purchase price, their higher energy consumption and maintenance costs can increase total expenses over time. Electric machines usually have higher upfront costs, but energy savings and reduced maintenance can significantly lower the total cost of ownership during the machine’s lifetime.
Rather than asking which machine is “better,” manufacturers should focus on which machine is more suitable for their application.
Hydraulic injection molding machines are well suited for:
Their strong force output and proven reliability make them a solid choice for many traditional molding tasks.
Electric injection molding machines are ideal for:
For manufacturers producing high-value or precision parts, electric machines offer clear advantages.
In addition to pure hydraulic and electric machines, hybrid injection molding machines combine elements of both technologies. Typically, key movements such as injection or screw rotation are electric, while clamping remains hydraulic.
Hybrid machines aim to balance energy savings with strong clamping force. They are often used where some benefits of electric machines are needed, but full electric systems are not required. However, because hydraulic systems are still present, energy efficiency and maintenance advantages are not as high as with fully electric machines.
To make a smart investment, manufacturers should evaluate several factors:
By clearly defining production needs, it becomes much easier to select the most suitable injection molding machine.
In summary, both electric and hydraulic injection molding machines play important roles in modern manufacturing. Hydraulic machines offer strong force and cost-effective solutions for many applications, while electric machines deliver superior precision, energy efficiency, and clean operation.
There is no single best solution for every factory. The right choice depends on product requirements, production goals, and long-term cost considerations.
As an experienced plastic injection molding machine manufacturer, NPC is committed to helping customers choose the right injection molding solution based on real production needs. With professional R&D, reliable manufacturing, and comprehensive after-sales support, NPC provides practical and efficient solutions for manufacturers worldwide.
If you are looking for a trusted plastic injection molding machine manufacturer to support your current or future projects, NPC is ready to work with you to achieve stable production and long-term success.
