What to Confirm Up Front (Specs / Descriptions)

When you talk to the seller, first get clear answers on:

• X, Y, Z travel (how far the machine can move in each axis).
• Table size and maximum load (how heavy the part / fixture you plan to use).
• Spindle speed and power (max RPM, torque, whether there’s high speed or heavy-cut capability).
• Type of tool changer (how many tools, speed, reliability).
• Type of control (what CNC brand, what software version, how maintained).
• Condition of the machine / year of manufacture / total hours of use or number of cycles.
• What extras or accessories are included (fixtures, tooling, coolant system, chip conveyor, etc.).

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What to Inspect & Test On-Site

Here’s what to check in person, to uncover wear or potential hidden issues:

1. Spindle and Bearings
   • Run the spindle at low and high speed: listen for vibration or unusual noise.
   • Check run-out (radial & axial): use a dial indicator to measure whether the spindle is true.
   • Inspect taper or chuck: any damage, excessive wear, or looseness.
2. Axis Motion (X / Y / Z)
   • Move each axis through its full range- check for smooth movement, no sticking or jerky motion.
   • Check for backlash or slack: reversals should be tight.
   • Look at guideways / rails: are they clean, well‐lubricated, with no rust or heavy marks? Are way covers intact?
3. Tool Changer / Tool Holding
   • Change tools a few times: is the mechanism fast & accurate? Any mis-grips or tools that don’t seat properly?
   • Inspect each tool holder: are they worn, deformed, or loose?
4. Control & Electronics
   • Power up the control: check display, buttons, readouts. <br> Check for alarm or error history.
   • Inspect wiring, electrical cabinet: any signs of heat damage, burned wires, corrosion, moisture.
   • Check limit switches, homing, safety interlocks, whether they function correctly.
5. Coolant / Lubrication / Pumps
   • If there is a coolant system, test its flow, check for leaks. Is fluid clean? Are the filters good?
   • Lubrication to ways / slides: does the lubrication system work? Are oil or grease points clean?
6. Table / Fixtures
   • Check table flatness, condition of T‐slots (if present). <br> See if the table holds its alignment under load.
   • Fixtures included? Are they in good condition?
7. Chip Removal and Cleanliness
   • Are chips cleaned away well, or is there accumulation that could damage surfaces or cause contamination?
   • Condition of guards or covers.
8. Accuracy & Test Machining
   • Run a sample part or test cut similar to what you’ll do; measure dimensions, surface finish, tolerances.
   • Check performance at different parts of the travel (not just center).
   • After the machine runs a while, check if accuracy or behaviour changes (heat drift etc.).
9. Wear & Maintenance Signs
   • Look for rust, discoloration, wear marks, sloppy joints. <br> Check if parts like bearings, seals, belts have been replaced or show heavy wear.
   • Ask for maintenance records: what was done and when.
10. Safety
    • Emergency stop & safety interlocks functioning. <br> Guards in place. Electrical safety (grounding etc.).
11. Installation, Power & Facility Fit
    • Machine weight, footprint – can you install it in your location? <br> Do you have proper power supply, coolant, ventilation etc.?

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What Raises Cost or Should Lower the Price

These are red flags. If you see several, either negotiate hard or walk away.

• Spindle run-out large or spindle noisy/vibrating.
• Worn or damaged guideways, especially if way covers are broken.
• Tool changer issues: mis-picks, slow operation, broken holders.
• Control panel or electronics in poor shape or obsolete (hard to find parts).
• Coolant or lubrication neglected; filters dirty; leaks.
• Table or fixtures badly worn or damaged.
• Inconsistent accuracy, especially over larger travels.
• No maintenance history or parts replaced.
• Safety features missing or not operational.