08/10/2025 By CNCBUL UK EDITOR Off

Technical Evaluation Guide: How to Identify a Quality Used, Secondhand, Pre-Owned, Surplus Sodick AG400L CNC Wire EDM made in Japan

1) Machine Overview & Important Specs

Before visiting the site, get the published specifications so you know expected tolerances and features. For the Sodick AG400L, some published data include:

Machine drive: linear motor axes (no backlash)
Table travels: X = 15.75 in (≈ 400 mm), Y = 11.81 in (≈ 300 mm), Z = 9.84 in (≈ 250 mm)
Work tank internal size: ~ 33.46” × 24.02” × … (dielectric tank)
Auto wire threading, submerged cutting capability
Dielectric (fluid) capacity: ~ 600 L
Maximum wire feed speed: about 420 mm/sec
Max workpiece weight: ~ 1,102 lbs (~500 kg)
Taper capability (standard): ±25°

These specs become your benchmark when verifying the actual machine condition.

2) Pre-Visit Document Request

Ask the seller to provide:

Original spec sheet / brochure for the exact AG400L unit
Serial number, build year
Control type and version (e.g. SPW, LN2W, or equivalent)
Usage hours / machine run hours
Maintenance logs (filter changes, dielectric system, wire guides)
Calibration / geometry reports
Spare parts list (wire guides, pump components, sensors)
Electrical schematics, wiring diagrams

Having these helps you know what “good” means and set acceptable wear limits.

3) Static / Visual Inspection

With power off, check the following:

Frame & base: look for cracks, repairs, corrosion, or distortions.
Tank / dielectric tank: check for leaks, cracks, rust, or deformation.
Wire guides / upper & lower: inspect for wear, chipping, or misalignment.
Auto wire threading (AWT) mechanism: inspect feed tubes, sensors, actuators for damage.
Linear motor axes: inspect way covers / protective sheets for damage, foreign debris.
Seals, bellows, covers: check for tears, dried coolant, or hardened deposits.
Connectors / cabling: look for damage, brittle insulation, burnt terminals.
Pump / plumbing / filter lines: examine for leaks, corrosion, or past repair.
Control panel / keys / display: check for wear, dead keys, LCD clarity.

4) Installation & Alignment Checks

If possible, mount or partially power:

Check axis movement by hand or low-speed jog (with safety) for smooth travel.
Use a test bar or gauge to check spindle / wire clamp alignment and runout in neutral position.
Command small XY moves and confirm the actual position via readback (if linear scale feedback).
Verify that taper axis (if present) is mechanically smooth; you may command a small angular move and check motion.

5) Power-On / Dynamic Tests

With everything powered (safely):

Warm up the machine by jogging axes repetitively for 30 minutes.
Run the wire EDM generator in a no-load / dummy cut mode. Observe for stable discharge without stray arcs.
Command auto-wire threading multiple times (≥ 5) — ensure success each time.
Run the wire at multiple speeds (low, mid, high) and monitor wire tension stability, vibration, or noise.
Observe linear motor drive currents / servo loads for anomalies, spikes, or drift.
Tilt / taper axis movement (if present) under small load or simulation — check for torque anomalies or sticking.
Monitor the dielectric fluid pump: consistent pressure, no cavitation or noise.
Control cabinet: check fans, heat, no error alarms during movement.

6) Accuracy, Repeatability & Metrology Tests

These are critical for EDM performance:

Positioning accuracy / linearity: Use a laser interferometer or calibrated displacement system to verify X / Y / Z axes (e.g. ±0.005 mm over travel or better).
Repeatability: Command back-and-forth moves (e.g. 10×) and measure deviation.
Wire cutting test: Cut a test shape (straight line, radius corner, taper) in a steel plate. Measure deviation from intended paths (for instance, hole diameter, corner sharpness, taper angle).
Corner accuracy: Test internal and external corners to verify that the machine maintains geometry through direction changes.
Hysteresis / residual drift: After moving to a position and holding, return to origin, then measure difference.
Thermal drift: Run under typical cutting load for an hour, then re-measure reference points to see if shift occurred.
Wire guide / alignment consistency: Check if the wire path remains true over the motion envelope.

7) Dielectric / Cooling / Filtration System Checks

Check dielectric fluid clarity, contamination, and conductivity (resistivity).
Inspect filters and resin units—they should have been changed regularly.
Check pump flow, pressure, and stability—no cavitation or pulsation.
Inspect plumbing, valves, hoses for leaks or clogging.
If the machine has a liquid-level auto adjustment feature or immersed cutting, test that system is functional.
Temperature control: confirm the dielectric/chiller keeps fluid temperature stable under load.

8) Wear & Failure Signs to Watch For

Worn wire guide inserts: cause taper drift or cut inaccuracy.
Auto-wire threading failures: intermittent or frequent errors.
Axis servo errors or overloads: repeated errors in movement.
Inconsistent dielectric pressure / foreign noise in pump.
Excessive drift / thermal instability.
Cracked or corroded tank / frame.
Electrical issues: burnt wires, error codes on CNC.
Non-responsive keys or display.
Missing or heavily worn parts, such as filters, seals, auxiliary modules.

9) Documentation & Records to Request

Original specification / brochure
Maintenance / service logs
Calibration / geometry reports
CNC parameter backups
Electrical / wiring diagrams
Spare parts listing
Warranty or past repair invoices

10) Acceptance Criteria / Target Values (Typical Benchmarks)

Parameter	Typical Acceptable Range	Notes / Specifications
Positioning accuracy (X, Y)	± 0.005 mm or better	Should be referenced against spec sheet
Repeatability	± 0.002 mm or better	After multiple cycles
Wire path deviation / taper error	Few microns over full cut	Corner-to-corner transitions minimal error
Auto-wire threading success rate	≥ 90–100 %	No repeated failures
Fluid temperature stability	± 0.5 – 1 °C	During extended run
Pump stability / pressure ripple	Minimal fluctuation	No cavitation noise
Wire tension stability	No major oscillations	During high-speed wire travel
Electrical / servo load stability	Smooth, no spikes	Under dynamic movement
Display / control responsiveness	No lag, no errors	All keys respond