Servo system for injection moulding machines

2 week ago

2 0 

4 year

Product details

I. System Composition & Core Components

1. Servo Motor

• Acts as the power source, outputting precise rotational speed and torque based on controller commands to drive the screw for plastic melting, injection, and other actions.

• Types include AC induction servos and permanent magnet servos (synchronous servos), with the latter becoming mainstream due to higher efficiency and faster response.

2. Driver

• Control technologies include variable frequency control and servo control; the former suits simple speed regulation, while the latter achieves high-precision control via closed-loop feedback.

• Receives encoder signals to adjust motor speed and torque in real time, ensuring system operation per preset parameters.

3. Pump Unit

• Types cover gear pumps, piston pumps, and vane pumps. Gear pumps (external, internal, and helical) are widely used for their simple structure and low cost.

• Converts mechanical energy from the motor into hydraulic energy to provide pressure and flow support for injection moulding machines.

4. Sensors & Feedback Devices

• Rotary Encoder: Monitors motor position and speed in real time, feeding data back to the driver for closed-loop control.

• Pressure Sensor: Installed at the pump outlet to monitor hydraulic system pressure, ensuring stability at set values.

• Control Card (PG Card): Converts communication interfaces to enable precise recognition of encoder signals by the driver.

II. Working Principles & Control Modes

1. Flow Control Mode

• When the pressure sensor detects pressure below the set value, the system enters flow control mode.

• The driver adjusts servo motor speed to make the pump output flow reach the preset value, meeting requirements for injection moulding stages (e.g., injection, holding, cooling).

2. Pressure Control Mode

• When the pressure sensor detects pressure at or above the set value, the system switches to pressure control mode.

• The driver regulates servo motor torque to stabilize pump output pressure and flow at set values, preventing overpressure or underpressure.

3. Closed-Loop Control Mechanism

• Through real-time feedback from encoders and pressure sensors, the driver continuously adjusts motor parameters to ensure output flow and pressure precisely match load demands.

• Eliminates overflow losses in traditional fixed-displacement pump systems, significantly reducing energy consumption.

III. Technical Advantages & Performance Characteristics

1. Significant Energy Savings

• Compared to traditional fixed-displacement pump systems, servo systems reduce electricity consumption by 30%–80%.

• Standby power consumption drops to as low as 3W; during holding and injection, power consumption is only 0.25KW (e.g., for an 11KW, 1500rpm, 80-bar hydraulic system).

• During cooling phases, the motor runs at low speed, consuming minimal energy; savings increase with longer cooling times.

2. High Control Precision

• Achieves precise control of position, speed, and pressure, significantly improving dimensional accuracy and quality consistency of moulded products.

• Uses speed control during injection to avoid stress concentration and mould sticking; employs pressure control during holding to ensure uniform density.

3. Fast Dynamic Response

• Servo motors start quickly and respond instantly to pressure and speed change commands.

• Maintains stability under sustained loads with short steady-state response times, ideal for short-cycle, high-frequency production.

4. Low-Noise Operation

• Adopts low-noise oil pumps (e.g., German gap pressure auto-compensating internal gear pumps), operating at noise levels as low as 63dB(A).

• During holding, injection, and standby cooling, the motor and pump run at low speed, minimizing noise interference.

IV. Application Scenarios & Selection Guidelines

1. Typical Application Fields

• Medical Industry: Producing high-precision medical devices (e.g., syringes, IV drips).

• Automotive Industry: Manufacturing automotive components (e.g., dashboards, bumpers).

• Consumer Electronics: Producing precision plastic parts (e.g., phone casings, computer accessories).

• Packaging Industry: Manufacturing food and consumer goods packaging.

2. Key Selection Factors

• System Compatibility: Choose manufacturers offering complete systems to avoid instability from mismatched components.

• Power & Torque: Select servo systems with appropriate power and torque for the injection moulding machine specifications to ensure stable pressure during high-pressure output.

• Magnet Grade: Opt for high-grade magnet servo motors to prevent demagnetization during prolonged overload operation.

• Installation Dimensions: Ensure motor and driver dimensions match for easy integration into existing equipment.

• After-Sales Service: Prioritize suppliers with comprehensive after-sales support for system maintenance and upgrades.

V. Market Trends & Development Directions

1. Intelligent Control Technologies

• Servo drive systems integrate intelligent algorithms to automatically adapt to complex production environments, adjusting parameters in real time for diverse needs.

• Leverage big data analytics to optimize production workflows, enhancing equipment utilization and efficiency.

2. Integrated Design

• Combine multiple control units into a single system to simplify structure, reduce failure points, and lower maintenance costs.

• Modular designs facilitate system expansion and upgrades to meet future production demand changes.

3. Advanced Energy-Saving Technologies

• Develop regenerative current storage and reuse technologies to further cut energy consumption.

• Optimize pump-motor matching to improve energy conversion efficiency.