Machine guide
Injection molding machine parts and their functions
The main parts of a plastic injection molding (moulding) machine, where each one sits and what it does, with the replacement parts we supply for each zone.
A horizontal injection molding machine has two halves on a common base. The clamping unit on the left opens, closes and holds the mold. The injection unit on the right melts the plastic and injects it into the mold. The hydraulic unit and the electrical cabinet in the base power and control both. The diagram above numbers the eleven zones described below, on a toggle-clamp machine such as the Haitian MA series. Every part number is also in the spare parts list (PDF).
1. Clamping cylinder
The hydraulic cylinder behind the rear platen. It drives the crosshead that straightens the toggle links, which opens and closes the mold and builds the clamping force.
Replacement parts for this zone
- Clamping CylinderMC-CC-01
- Clamping Cylinder — Small / AuxiliaryMC-CC-02
Guides
Guide to the clamping cylinder and its 2 parts2. Toggle mechanism
Links, pins and bushings between the rear and moving platens. They multiply the force of the clamping cylinder and lock the mold shut while plastic is injected.
Replacement parts for this zone
- Toggle Link / CrossheadMC-CR-02
- Toggle Pin BushingMC-JM-02
- Toggle Link Connecting Rod BushingMC-JM-05
- Toggle Arm / Link RodMC-TL-02
- Toggle Pin / Hinge PinMC-TL-03
- Toggle Link BushingMC-TL-05
Guides
Guide to the toggle mechanism and its 6 parts3. Ejector
A small cylinder behind the moving platen that pushes the ejector rods and plate forward to release the finished part from the mold.
Replacement parts for this zone
- Ejector RodMC-ES-08
- Ejector Connecting Plate & Pin KitMC-ES-09
- Return Spring / Ejector SpringMC-SR-05
Guides
Guide to the ejector and its 3 parts4. Tie bars & bushings
Four steel columns that join the platens, guide the moving platen and carry the clamping force. Tie bar nuts lock them in place; bushings guide the moving platen along them.
Replacement parts for this zone
- Guide Column Nut (Type 2)MC-GZ-02
- Guide Column Nut (Type 3)MC-GZ-03
- Locking Nut / Jam NutMC-GZ-04
- Guide Column Bushing (Small)MC-GZ-5
- Guide Column Bushing (Medium)MC-GZ-6
- Guide Shaft / Connecting LinkMC-GZ-07
- Guide Column Bushing (Large)MC-GZ-10
- Tie BarMC-TC-01
- Tie Bar Liner BushingMC-TC-03
- Tie Bar NutMC-TC-06
- Tie Bar BushingMC-TC-07
- Tie Bar Adjustment BushingMC-TC-09
- Tie Bar End Cap / Lock RingMC-TC-13
- Tie Bar Set (Pair)MC-TC-0102
Guides
Guide to the tie bars & bushings and its 14 parts5. Platens & mold plates
The fixed and moving platens carry the two halves of the mold; the rear platen anchors the toggle. Locating rings and clamping plates center and hold the mold.
Replacement parts for this zone
Guides
Guide to the platens & mold plates and its 2 parts6. Barrel, screw & nozzle
The screw turns inside the heated barrel to melt and mix the plastic, then moves forward to inject it through the nozzle into the mold. The screw tip and check ring stop melt from flowing back.
Replacement parts for this zone
- Bimetallic Barrel & Screw AssemblyMC-BC-01
- Injection ScrewMC-BC-02
- Injection NozzleMC-BC-07
- Barrel Front Flange (Front Head)MC-BC-08
- Screw Head Wrench (3-Prong / 4-Prong / 6-Prong)MC-GMP-01
- Screw Barrel AssemblyMC-SB-01
Guides
- Screw
- Barrel
- Check ring
- Screw tip
- Nozzle
- Shut-off nozzle
- Nozzle filter
- Barrel head
- Hopper and feed throat
- Bimetallic barrel
- L/D ratio
- Back pressure
- Shot size calculation
- Removing the screw
7. Heater bands & sensors
Heater bands around the barrel and nozzle melt the plastic. Thermocouples measure each heating zone so the controller can hold the set temperature.
Replacement parts for this zone
- Ceramic Heater BandEC-HT-01
- Thermocouple SensorEC-HT-02
- Barrel Heating Band Removal ToolMC-GMP-02
Guides
- Heater band types
- Nozzle heater
- Thermocouple
- Temperature control
- Barrel temperature zones
- Replacing heater bands
8. Injection unit
Injection cylinders push the screw forward, the hydraulic (plasticizing) motor turns it, and the carriage moves the unit against the mold on its guide rails.
Replacement parts for this zone
- Hydraulic Plasticizing Motor (NHM Series)HY-PW-08
- Injection CylinderMC-BC-06
- Injection Piston RodMC-GZ-01
- Piston Rod Seal SetMC-SB-07
- Hydraulic Cylinder Seals & Y-RingMC-SB-08
- Piston Rod NutMC-SB-10
- Linear Guide Rail & SliderMC-SG-08
Guides
Guide to the injection unit and its 7 parts9. Hydraulic unit
The pump, motor, valves, accumulator, filters and oil cooler in the machine base. They supply and control the oil pressure for every movement of the machine.
Replacement parts for this zone
- Hydraulic AccumulatorHY-AU-02
- Directional Control ValveHY-CV-02
- Proportional Pressure/Flow ValveHY-CV-04
- Check ValveHY-CV-05
- Relief Valve / Safety ValveHY-CV-06
- Cartridge ValveHY-CV-08
- Solenoid Operated Valve — High FlowHY-CV-15
- Hydraulic Pressure GaugeHY-MO-01
- Gear Pump (Sumitomo QT32)HY-PW-02
- Hydraulic Power Unit / Oil Pump AssemblyHY-PW-03
- Pump Coupling & Bell HousingHY-PW-05
- Hydraulic Vane PumpHY-PW-06
- Hydraulic Piston PumpHY-PW-07
- Hydraulic Oil FilterO-TC-02
- Oil Cooler / Heat ExchangerO-TC-04
- Oil Tank / Hydraulic ReservoirO-TC-05
Guides
- Hydraulic circuit
- Hydraulic pump types
- Vane pump
- Piston pump
- Gear pump
- Servo pump system
- Pump coupling
- Hydraulic power unit
- Directional valve
- Proportional valve
- Cartridge valve
- Hydraulic check valve
- Relief valve
- Valve manifold
- Accumulator
- Hydraulic oil
- Oil temperature
- Oil filter
- Oil cooler
- Oil tank
- Cooling water manifold
- Pressure gauge
- Pressure transducer
10. Electrical cabinet
The controller, I/O and drive boards, servo drives, contactors and safety switches that run and protect the machine.
Replacement parts for this zone
- Controller Board — I/O ModuleEC-CBC-06
- Controller Board — Main CPU BoardEC-CBC-12
- Controller Board — Drive InterfaceEC-CBC-13
- Controller Board — Power Supply BoardEC-CBC-14
- Electrolytic CapacitorEC-CE-01
- Film Capacitor / Filter CapacitorEC-CE-02
- AC Servo MotorEC-GEP-01
- Safety Switch / Limit SwitchEC-SF-01
- Proximity Sensor / Position SensorEC-SF-03
Guides
- Control panel
- Controller
- I/O module
- Power supply board
- Drive interface board
- Servo motor
- Servo drive
- Encoder
- Capacitors
- Limit switch
- Proximity sensor
- Linear transducer
- Safety gate
11. Machine feet
Leveling bolts and anti-vibration pads under the machine base that keep the machine level and stop vibration spreading to the floor.
Replacement parts for this zone
- Machine Leveling Foot BoltMC-TL-01
- Anti-Vibration Foot PadMC-TL-07
Guides
Guide to the machine feet and its 2 partsSourcing
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