Old Injection Molding Machine

Updated: 2026-08-06

Overview

Used injection molding machines are industrial assets that have completed partial service life but retain functional value. These second-hand units offer 30-70% cost savings versus new equipment, making them attractive for startups or expanding manufacturers. Common brands in the secondary market include Haitian, Engel, Arburg, and Toshiba. Market availability ranges from 1980s hydraulic models to early-generation electric machines. Buyers should note that older machines may lack modern energy efficiency or precision controls, though many can be upgraded with retrofitted automation components.

Structure and Working Principle

A typical used injection molding machine retains the core components: injection unit (screw and barrel), clamping unit (platen and toggle/tie-bar system), hydraulic/pneumatic system, and control panel. The working principle involves plasticizing polymer granules in the barrel, then injecting the melt into a closed mold under high pressure (commonly 500-2,500 bar). Critical wear areas to inspect include screw flight integrity (especially near the tip), barrel inner diameter wear (measured with pin gauges), and hydraulic cylinder seals. Older machines often use relay-based controls rather than modern PLC systems, which may limit programming flexibility but simplify repairs.

Key Features

Production capacity in used machines is measured by clamp force (20-4,000 tons typically) and shot weight (grams to kilograms). Many units feature mechanical wear indicators or hour meters to estimate remaining service life. Energy consumption varies significantly - older hydraulic models may use 30-50% more power than modern equivalents. Desirable features in second-hand purchases include preserved mold mounting plates (no tapped hole damage), functioning ejector systems, and verifiable maintenance logs. Some refurbished units come with upgraded temperature controllers or safety interlocks to meet current standards.

Application Areas

Pre-owned injection molders serve diverse industries: packaging (thin-wall containers), automotive (interior trim components), medical (non-critical device housings), and consumer goods. Smaller machines (under 100 tons) are popular for prototyping or short production runs. Specialized applications require verifying machine specs - for example, LSR molding needs precise temperature control, while engineering resins demand high injection pressures. Many buyers repurpose used machines for educational/training purposes where production volume isn't critical.

Maintenance and Precautions

Post-purchase maintenance should include hydraulic oil/filter replacement (especially if service history is unknown), screw/barrel inspection for wear beyond 0.2mm clearance, and re-greasing of toggle mechanisms. Electrical systems require insulation testing, particularly in humid environments. Safety precautions include verifying emergency stop functionality, guarding moving parts per OSHA/CE standards, and checking for oil leaks in hydraulic systems. For machines stored idle, proper preservation of injection units (purged clean) and rust prevention on platens are essential.

B2B Procurement Guide

When sourcing used equipment, prioritize sellers providing test reports with key parameters: dry cycle time consistency, clamp force verification, and injection speed repeatability. Third-party inspections are recommended for high-value purchases (>$20,000). Logistics considerations include foundation requirements (older machines often need thicker concrete bases) and disassembly/rigging costs. Many Asian-manufactured machines require voltage/phase conversion in Western markets. Warranty terms vary - reputable dealers may offer 3-6 month coverage on major components.