08/10/2025 By CNCBUL UK EDITOR Off

Technical Evaluation Guide: How to Identify a Quality Used, Secondhand, Pre-Owned, Surplus Mazak SQT 10MS CNC Lathe made in Japan

1) Machine Overview & Baseline Specifications

First, obtain the factory specification sheet or previously documented specs for the exact SQT 10MS unit. Below are representative specs from listings of the model:

Max turning diameter: ~ 9.06 in (~230 mm)
Max machining length (Z travel): ~ 12.05 in (~306 mm)
X-axis stroke: ~ 6.31 in (~160 mm)
Z-axis stroke: ~ 17.93 in (~455 mm)
Spindle speed: 35 – 6,000 rpm (stepless)
Spindle bore (bar capacity): ~ 2.40 in (≈ 61 mm) bore; bar work diameter ~1.65 in (~42 mm)
Turret: 12-station drum turret, live tool capability
Secondary spindle (sub spindle) specification: speed 180–6000 rpm, some units include second spindle / B-axis stroke ~18 in
Controller: Mazatrol T-32-3 (common for SQT10MS)

These values serve as your target benchmarks. Any used machine should be reasonably close to these (aside from allowable wear or optional variants).

2) Documentation & Pre-Visit Checklist

Before visiting, request from the seller:

Serial number, manufacturing year, and full build/configuration sheet (options, live tools, sub spindle)
Maintenance and service logs (spindle rebuilds, axis overhauls, lubrication, repairs)
Geometry / calibration / test reports (ballbar, laser, runout, straightness)
CNC parameter backups, offset / compensation tables
Electrical, pneumatic, hydraulic, and wiring diagrams
List of tooling, live tool holders, turret options
Alarm history or fault logs
Records of any collisions, crashes, or major repairs

These documents help you understand how far the machine may have drifted or been modified.

3) Static & Visual Inspection (Machine Off / Unpowered)

Walk around the machine carefully and inspect:

Frame & Castings
Check for cracks, weld repairs, distortion, evidence of collisions, surface fatigue.
Way Covers / Bellows / Guards
Look for tears, missing sections, chip damage, hardened deposits.
Turret & Tool Magazine
Inspect turret face, tool pockets, gripper fingers, indexing surfaces. Check for play or misalignment.
Spindle Nose & Taper
Check for corrosion, scratches, dents, or pitting.
Guideways / Slides / Carriage
Inspect for scoring, uneven wear, discoloration, lubrication residue.
Sub Spindle / Secondary Spindle (if present)
Inspect for damage, alignment, carriage movement.
Cable Carriers / Hoses / Wiring
Look for brittle insulation, worn drag chain links, repairs, missing coverings.
Electrical Cabinet / Wiring
Open panel; observe wiring quality, burnt traces, component discoloration, modifications.
Coolant / Fluid Lines / Fittings
Check for leaks, brittle hoses, corrosion, past repairs.
Safety Devices / Doors / Interlocks
Ensure guards are in place, doors close flush, interlocked switches exist.

Take high-resolution photos of areas of concern.

4) Installation & Alignment Checks

If the machine is partially installed or mounted:

Ensure the machine is leveled and properly anchored (no excess shims or flex).
Mount a test bar / indicator in the spindle at neutral position, measure radial runout to confirm spindle alignment.
Jog the X and Z axes through small moves; feel for binding, stiff spots, or uneven motion.
Rotate the turret face / index the turret and measure lateral positional consistency relative to spindle.
If parting devices or tailstock are present, align those to spindle axis and check for offset.

5) Power-On & Motion / Functional Tests

Once powered and with safety protocols:

Warm up the axes via jogging for ~20–30 minutes to stabilize lubrication and thermal conditions.
Execute home / zero-return cycles and check for repeatability and no limit / reference errors.
Command full-axis strokes (X, Z) at variable speeds (25 %, 50 %, 100 %) — listen for chatter, binding, or irregular movement.
Cycle the turret through all indexing stations repeatedly; look for mis-index, hesitation, or alarms.
Ramp the main spindle from low to max rpm, monitoring vibration, sound, current, and temperature.
Run a few live tool / milling operations (if equipped) at light loads to check the live tooling spindle behavior and stability.
Engage coolant and lubrication systems; monitor flow, pressure, and leaks.
Exercise sub spindle (if present) and test its synchronization, motion, and locking.
Review CNC alarm/fault logs and attempt to provoke minor errors to test error handling.
While moving axes, monitor encoder feedback, servo currents, check for dropouts or anomalies.

6) Accuracy, Repeatability & Metrology Tests

These evaluate true performance under load:

Use laser interferometer or precision gauge(s) to test linear positioning / straightness on X & Z axes.
Perform small ±0.01 mm reversal moves and measure backlash / direction reversal error.
Conduct repeated moves to a target position (e.g. 10×) and measure repeatability error.
Index the turret repeatedly to same station and measure tool location repeatability.
For live tool operations, command a small milling or drilling move and verify that tool positioning matches expected.
For subspindle units, perform part transfer operations and check concentricity / alignment.
Run a test cut (turn + mill) on a sample workpiece and measure critical dimensions (diameter, length, hole placement).
After continuous operation (1 hour or more), recheck reference dimensions to capture thermal drift.
Perform a hysteresis test: move to a point, dwell, return, then measure offset from original.

7) Spindle, Tooling & Wear Checks

Mount a high-precision test bar in the spindle and measure radial runout.
Use a vibration analyzer or listen for noise anomalies at intermediate rpm to detect bearing issues.
Monitor spindle temperature over a 30-minute run — it should remain stable without excessive rise.
Test tool retention force (if applicable) or check gripper hold in live tool holders.
Use dye / blue contact test to confirm that the taper seating is uniform and contact area is good.
Cycle tool changes multiple times, inspect tool change repeatability and offset consistency.
If equipped with live tooling, test for runout, vibration, and repeatability of milling spindle.

8) Lubrication, Cooling & Auxiliary Systems

Check that the lubrication / grease / oil supply to axes, turret, slides is active and no blocked lines or leaks.
Run coolant system; check pump flow, pressure, clarity, and leak paths.
Inspect filters, screens, coolant tanks for cleanliness, sludge, rust.
Operate chip conveyor / removal path; check for jamming, alignment, smooth motion.
Test any hydraulic / pneumatic systems (e.g. turret clamping, tailstock) for smooth operation and pressure stability.
Ensure electrical cabinet cooling and ventilation fans are working; no overheating in drive compartments.

9) Common Wear Patterns & Risk Indicators

X / Z guideway wear or scoring (especially mid-travel)
Turret indexing wear or backlash
Spindle bearing fatigue / vibration
Tool changer / gripper wear or looseness
Live tooling spindle wear or instability
Loss of lubrication (blocked lube circuits)
Coolant leaks, corrosion, or contamination in bed or way surfaces
Servo drive or control board aging, heat stress, failed components
Encoder or feedback dropout errors
Cable harness aging, insulation degradation

10) Acceptance Criteria & Benchmark Tolerances

Use these as your “go / no-go” thresholds (adjust based on spec sheet and acceptable application tolerances):

Parameter	Target / Acceptable Tolerance
Linear positioning accuracy (X, Z)	± 0.005 mm over moderate stroke
Backlash / reversal error	≤ 0.01 mm
Repeatability (X, Z)	± 0.005 mm or better
Turret index repeatability	≤ 0.01 mm
Spindle radial runout	≤ 0.005 mm
Thermal drift over 1 hour	≤ 5–10 µm
Tool change offset repeatability	≤ 0.01 mm
Coolant / lubrication stability	No large pressure or flow drop under load
Servo / current stability	Smooth traces, no sudden spikes
Noise / vibration at rpm	Low — no abnormal bearing whine or vibration peaks