7 Questions Before Buying Used Injection Molding Machines
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<p>Buying a used injection molding machine can save 40-60% vs new but only if you ask the right questions first.</p>
<p><strong>1. What is the actual service history?</strong></p>
<p>Look for documented oil changes, screw/barrel replacement, hydraulic filter changes. Missing logs = higher risk.</p><p><strong>2. Has the screw or barrel been replaced?</strong></p>
<p>Screw OD wear over 0.5mm reduces performance significantly. New barrel costs 2000-8000; new screw costs 800-3000.</p><p><strong>3. What is the tie-bar tension reading?</strong></p>
<p>Uneven tension (20%+ variation between bars) indicates uneven loading. Can be re-tensioned, but check for platen damage.</p><p><strong>4. Is the injection unit aligned properly?</strong></p>
<p>Check nozzle centerline alignment to the stationary platen. Misalignment causes excessive wear on guide bushings.</p><p><strong>5. What controller is installed?</strong></p>
<p>Older controllers prior to 2015 may have obsolete parts. Verify manuals and backup files are included.</p><p><strong>6. How does the hydraulic system look?</strong></p>
<p>Check for oil discoloration (milky = water contamination). Listen for pump cavitation during dry cycle. Check all hoses for cracks near fittings.</p><p><strong>7. Are spare parts and documentation included?</strong></p>
<p>A set of spare heater bands and seals is valuable. Ask for electrical schematics and hydraulic diagrams.</p><p><strong>Final Tip:</strong> Bring a mold you already run successfully and do a trial run. A 30-minute test can save you thousands in surprises.</p>
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<p>One thing I’d add: always check the injection unit barrel wear before buying a used machine. A worn barrel can cost you 30% more in energy.</p>