Spare Parts for Injection Molding Machines
I. Core Spare Part Types & Functions
1. Molding System Components
• Screw & Barrel: Responsible for plasticizing, conveying, and injecting plastic materials. Screw parameters (diameter, length-to-diameter ratio, compression ratio) directly impact plasticizing quality and injection efficiency. For example, high-viscosity plastics (e.g., PC) require screws with extended compression sections, while heat-sensitive plastics (e.g., PVC) need shorter metering sections to minimize thermal degradation risks.
• Nozzle & Runner System: Controls melt flow paths. Nozzle diameter must match the injection unit's specifications, and runner design affects filling speed and cooling efficiency.
2. Clamping System Components
• Platens & Molds: Fixed and moving platens support molds. Clamping force must align with the projected area of the product (typically ≥ product projected area × mold pressure / 0.8 / 1000).
• Guide Pins/Bushes: Ensure clamping precision; worn components require replacement to avoid clamping deviations.
• Ejection System: Push rods, push tubes, and reset rods facilitate demolding, requiring regular wear and lubrication checks.
3. Hydraulic & Electrical System Components
• Hydraulic Valves & Cylinders: Control clamping, injection, and ejection motions. Regular inspection of seals and oil circuit cleanliness is essential.
• Sensors & Controllers: Monitor parameters like temperature, pressure, and position to ensure process stability.
4. Auxiliary System Components
• Cooling Water Channels & Heating Elements: Maintain mold temperature. Cooling nozzles require periodic cleaning to prevent blockages, while heating plates must be checked for insulation integrity.
• Lubrication System: Reduces wear on moving parts; lubricating oil must be replenished or replaced regularly.
II. Selection Criteria & Considerations
1. Compatibility Verification
• Spare parts must fully match the injection molding machine model and mold design. For instance, screw diameter must align with the injection unit's specifications, and mold thickness must fall within the machine's mold capacity range.
• Prioritize original or certified suppliers to ensure materials (e.g., wear-resistant alloys, corrosion-resistant coatings) and machining precision meet requirements.
2. Quality & Performance Standards
• Critical components (e.g., screws, molds) must comply with ISO 9001 certification, and materials must adhere to RoHS, REACH, and other environmental regulations.
• Hydraulic components must withstand high pressures (typically 140–210 bar system pressure), while electrical components must meet dust/water resistance standards (e.g., IP65 rating).
3. Cost-Effectiveness & Lifespan Assessment
• Select economical or high-performance spare parts based on production needs. For example, high-wear-resistant screws are ideal for long-term high-load production, while standard screws suit medium/small batch production.
• Evaluate part lifespan based on usage frequency and maintenance levels. For instance, guide pins/bushes typically require replacement every 2–3 years, and hydraulic oil every 5,000 hours.
