Variable Pump Servo Injection Molding Machine

This hydraulic injection molding machine integrates an axial variable displacement piston pump with a high-response permanent magnet synchronous servo motor. Designed for medium-to-heavy industrial plastic processing, the system dynamically adjusts hydraulic oil flow and pressure based on real-time load demand across injection, holding, cooling, and ejection phases.
By eliminating idling overflow losses inherent to fixed-displacement pump designs, the servo variable pump system reduces total electrical energy consumption by 30% to 55%. The closed-loop pressure and speed control response time is under 40 ms, ensuring stable hydraulic output during high-pressure holding stages and low-speed movements. Available in clamping force capacities ranging from 900 kN to 12,800 kN, this series caters to thin-wall packaging, automotive components, technical industrial fittings, and consumer durables.
System Operation & Architecture: The core system links a closed-loop controller directly to the servo motor and variable displacement pump assembly. This dynamic setup constantly regulates oil flow and pressure, delivering precise hydraulic energy directly to the actuators only when required by the cycle.

Dynamic Swashplate Adjustment: The displacement pump uses a swashplate mechanism linked to the servo driver. Swashplate angle changes match proportional flow demands instantly without excess heat generation.
Five-Point Double-Toggle Clamping: High-tensile cast iron platens driven by hardened steel toggle pins distribute clamping force evenly, preventing platen deflection and mold flash.
Nitride-Treated Bimetallic Screw & Barrel: Ion-nitrided carbon steel barrel with SACM 645 screw flight tipping ensures wear resistance against glass-fiber filled resins up to 30% loading.
Proportional Back-Pressure Control: Digital proportional valves adjust back-pressure dynamically during plasticizing, preventing melt voids and optimizing batch-to-batch density uniformity.
Linear Guide Rails on Injection Unit: Twin linear guide bearings support the injection unit carriage, eliminating tilting torques and preserving nozzle alignment under peak injection pressures.

The machine layout isolates mechanical load stresses while optimizing hydraulic path distances through three integrated core sections:

Hydraulic Power Pack (Central Drive): Integrates an axial piston variable pump mounted directly to a synchronous servo motor shaft. It supplies dynamic hydraulic pressure and oil flow to both the clamping unit and injection unit. An integrated oil cooler unit maintains fluid stability under cyclic operation.

Clamping Unit (Left Section): Features spherical graphite cast iron platens housing a five-point double-toggle linkage system driven by the central hydraulic pack. Includes an automatic lubrication system, and high-tensile tie bars treated with ultrasonic flaw detection and hard-chrome plating (0.03 to 0.05 mm thickness) to minimize guide bushing wear.

Injection Unit (Right Section): Powered symmetrically along the screw axis by dual-cylinder hydraulics. Equipped with twin linear guide rails to preserve nozzle alignment, a nitrided bimetallic screw and barrel assembly, and ceramic heater bands managed by PID loop controllers.

Control Architecture: An industrial PLC runs real-time fieldbus communications (CANbus/Ethernet) with microsecond response times for precise monitoring of temperature, position, and pressure across all units.

Energy Consumption Efficiency: Standard fixed pump machines operate at continuous maximum power output (100% consumption throughout the cycle). In contrast, the servo variable pump dynamically scales motor output and oil flow to real-time machine demand, using only 45% to 65% of full load power during operation and cutting overall electrical consumption by 35% to 55% per production cycle.
Reduced Thermal Load on Hydraulic Fluid: Because the pump alters displacement rather than bypassing pressurized oil back to the reservoir during hold and dwell cycles, oil temperature remains stable below 45 degrees C. Oil cooling water consumption decreases by up to 60%, and hydraulic oil lifespan doubles from 2,000 operational hours to 4,000+ hours.
Position Precision & Repeatability: Closed-loop linear optical transducers monitor clamping and injection movement. Mold opening and closing position accuracy reaches +/-0.1 mm, while injection transition repeatability to holding pressure stays within +/-0.05 mm.
Low Noise Emissions: Operating noise levels remain between 68 dB(A) and 73 dB(A) even during high-pressure injection phases, meeting European CE workplace noise guidelines without full acoustic enclosures.

Automotive Interior & Exterior: Engine bay brackets, door panel clips, HVAC ducting, trim clips, and connector housings requiring high structural integrity and tight dimensional tolerances.
Industrial & Plumbing: Pipe couplings, valve bodies, electrical junction boxes, cable glands, and heavy-duty utility enclosures.
Household Products & Furniture: Structural furniture components, appliance chassis, crate handles, and storage bin lids requiring long hold times without thermal degradation.
Thin-Wall Packaging: Food containers, lids, and packaging caps produced on high-speed injection cycles using multi-cavity hot-runner molds.

High-Torque Hydraulic Motors: Recommended for high-viscosity resins like PC, PBT, and thick-wall POM components requiring elevated plasticizing torque.
Corrosion-Resistant Electroplated Screw Sets: Specially designed for PVC, Flame-Retardant ABS, or CPVC applications to prevent chemical erosion of metal surfaces.
Accumulator-Assisted Injection: Nitrogen accumulators can be integrated for high-velocity thin-wall injection applications exceeding 300 mm/s.
Core Puller Units: Single, double, or multi-circuit hydraulic core pull interfaces programmable directly through the main PLC screen.
Air Injection Valves: Pneumatic ejector valves for blown-part ejection or complex mold release mechanisms.

Casting Integrity: Machine bases are fabricated from stress-relieved Q235B structural steel, annealed at 600 degrees C to eliminate internal welding stress prior to machining.
Precision Machining: Platens, slide beds, and toggle links undergo single-setup machining on 5-axis horizontal CNC machining centers to ensure parallel tolerances within 0.05 mm per meter.
Quality Verification & Inspection Protocol:
Coordinate Measuring Machine (CMM) checks for tie-bar parallelism, platen squareness, and hole center distances.
Ultrasonic Non-Destructive Testing (NDT) verifies tie-bar material density and detects internal cracks or inclusions.
24-Hour Dry-Run Testing: Every unit undergoes a continuous 24-hour dry-cycling test to check hydraulic heat rise, electrical loop continuity, and lubrication flow.
Full Load Pressure Holding Verification: Hydrostatic testing on all manifold blocks and valves up to 21 MPa prior to machine assembly.

Platen Dimensions & Daylight Extensions: Custom platen dimensions, extended tie-bar clear distances, or enlarged mold daylight distances to accommodate deep-draw molds or thick core-pulling molds.
Custom Screw Geometry: Specific screw designs including barrier screws, mixing pins, and specialized L/D ratios (up to 26:1) tailored to masterbatch dispersion or shear-sensitive resins.
Interface Compatibility: Integration of Euromap 12 or Euromap 63 robot interfaces, SPI protocols, and standardized auxiliary power sockets (16A / 32A) matching regional electrical standards (208V / 230V / 400V / 480V at 50 / 60 Hz).

To receive an accurate technical quotation and machine sizing calculation, provide the following production details:
Part Geometry & CAD Files: Part dimensions, wall thickness distribution, 3D file (.STEP / .IGES), or part weight (grams).
Resin Material Grade: Specific polymer type, filler percentage (e.g., PA66 + 30% GF), and melt flow index (MFI).
Mold Specifications: Mold dimensions (Length x Width x Height), weight, number of cavities, and hot runner design.
Target Output Requirements: Desired cycle time, required annual production volume, and robot automation needs.
Regional Electrical Requirements: Factory operating voltage, phase, and frequency (e.g., 400V, 3-Phase, 50 Hz).

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