18/10/2025
How Smart Engineers Assess a Pre-Owned, Used, Second-Hand, Surplus Jinan Grace G3020 – CNC 5 Axis Router made in China Before Purchase
Here’s a complete professional guide on how smart engineers evaluate a pre-owned, used, second-hand, or surplus Jinan Grace G3020 CNC 5-Axis Router made in China before purchase — ensuring technical, mechanical, and economic soundness.
Smart Engineer’s Assessment Framework
Smart engineers follow a 4-stage process:
- Technical verification — Does the machine match your production needs?
- Condition inspection — What is the actual state of mechanical, electrical, and control systems?
- Operational validation — Does it perform accurately under load?
- Commercial evaluation — Is it a financially and logistically sound investment?
1. Technical Verification – Model, Capability & Configuration
Machine Identification
- Model: Jinan Grace G3020 CNC 5-Axis Router
- Manufacturer: Jinan Grace Industry Co., Ltd.
- Origin: Made in Jinan, Shandong Province, China
- Typical Specs:
- Working area: 3000 × 2000 × 1000 mm (varies slightly by variant)
- Axis configuration: X, Y, Z + A (rotary) + C (tilt)
- Spindle power: 9–12 kW HSD or Chinese-made HQD spindle
- Spindle speed: up to 24,000 rpm
- Control system: Syntec 6MB or NcStudio (occasionally Siemens 808D or FANUC optional)
- Tool change: manual or automatic ATC (8–12 tools carousel)
- Drive: Yaskawa servo or stepper depending on build year
- Frame: steel welded bed + cast gantry (optional helical rack drive on X/Y)
Verify configuration matches your application
| Application | What to Verify |
|---|---|
| Mold making / 3D machining | Z-axis travel ≥ 700 mm, 5-axis simultaneous capability |
| Wood / composite panel | Dust extraction system + vacuum table |
| Aluminum or brass | Rigid frame + HSD/HQD spindle ≥ 9 kW + water cooling + chip evacuation |
| Stone / acrylic | Waterproof table + reinforced gantry + dust protection |
Documentation check
- Nameplate with model & serial number
- CE / ISO certificates (if exported to EU or Turkey)
- Electrical diagrams and parameter backup files
- Tool list, collet sizes, ATC specification
2. Condition Inspection – Mechanical, Electrical & Structural
Mechanical
- Bed and Gantry Alignment: Use precision level & dial indicator to check flatness & squareness.
- Ball Screws / Linear Guides: Check for backlash, smooth travel, no noise.
- Rack & Pinion (Y/X): Look for lubrication quality and teeth wear.
- Spindle bearings: Run at low and high RPM, listen for noise or heat rise > 50 °C.
- Tool holder taper: Check for run-out ≤ 0.01 mm (ATC cone clean and undamaged).
- Table surface: Vacuum seal check, flatness across entire 3000×2000 mm area.
- Axis brakes: Confirm Z-axis does not drift when power off.
Electrical / Control
- CNC controller: Confirm boot-up OK, no error codes. Check for battery alarms or parameter loss.
- Servo drive status: Check Yaskawa / Delta drive alarms and fan operation.
- Cable harnesses: Inspect drag chains for cracked wires or broken connectors.
- Cooling & fans: Ensure spindle chiller and control cabinet fans run properly.
- Emergency stop and limit switches: Test safety chain functionality.
Pneumatic / Vacuum System
- Leak test vacuum pump and air lines.
- Check air pressure switch (≥ 6 bar) and filters for moisture.
- For dust extraction, inspect ducting and motor bearings.
3. Operational Validation – Performance & Accuracy
Perform a live test if possible.
Motion & Accuracy
- Jog all axes full travel – no jerks or vibration.
- Measure positional accuracy with dial indicator or laser interferometer:
- Linear repeatability: ≤ ±0.03 mm over full travel.
- Rotary axes (A/C): indexing repeatability ≤ ±0.02 °.
- Verify axis synchronization during 5-axis simultaneous movement (smooth feed).
Spindle test
- Run at various RPM (6 000 / 12 000 / 18 000 / 24 000).
- Measure vibration and current draw; listen for bearing noise.
- Check ATC tool change cycle time and error rate.
Machining test
- Cut test piece (aluminum block or MDF board): inspect surface finish and dimensional accuracy.
- Check for thermal drift after 30 min continuous operation.
- Verify tool length compensation and offset system work correctly.
4. Commercial & Logistical Evaluation
Cost Analysis
| Cost Element | What to Confirm |
|---|---|
| Purchase Price | Compare to similar G3020 used machines (typical range USD 10 000 – 25 000) |
| Transport & Installation | Shipping weight ≈ 6 000–7 000 kg → check rigging costs |
| Retrofit / Repair | Budget for spindle rebuild (~USD 2 000–3 000) or ball screw replacement |
| Controller upgrade | Optional upgrade to Siemens 808D or Syntec 21 = USD 2 500–5 000 |
| Spare Parts Availability | Confirm local supplier for HQD/HSD spindles, Syntec drives etc. |
Logistics & Support
- Verify export documents and customs clearance (HS code 845 CNC router).
- Request contact for Jinan Grace after-sales or authorized service agent.
- Confirm availability of remote support (Syntec TeamViewer / parameter backup).
Contract Checklist
- Include inspection under power clause.
- Warranty period (even 30 days) for spindle and control.
- List all included accessories (ATC tools, vacuum pump, chiller, dust extractor).
- Specify responsibility for disassembly and re-commissioning.
Common Red Flags
| Issue | Risk |
|---|---|
| Cracked or warped machine bed | Non-recoverable geometry error |
| Excessive spindle noise or heat | Bearing failure → downtime + $ 3 000 repair |
| Loose rotary axis gearing | Poor 5-axis accuracy |
| Obsolete NcStudio software (no license) | Cannot reload parameters after power loss |
| Incomplete vacuum / dust system | Reduced holding force, surface defects |
| Missing manuals or backups | Hard to troubleshoot post-installation |
Decision Summary Table
| Evaluation Category | Target Condition | Action if Fails |
|---|---|---|
| Geometry / Alignment | Flatness ≤ 0.05 mm / m | Negotiate price or regrind bed |
| Spindle Performance | Smooth operation < 50 °C | Replace bearings |
| Electrical System | No alarms / stable servo | Re-parameterize controller |
| ATC / Vacuum System | Fully operational | Budget repairs ~USD 1 000 |
| Control Software | Licensed Syntec/NcStudio | Upgrade controller |
| Documentation | Complete & verified | Request digital copies |
| Support & Spares | Local dealer available | Stock critical spares (Spindle, Servo drive) |
Final Professional Advice
- Insist on a live demonstration under power with at least a 30-minute machining test.
- Measure part accuracy (using a dial indicator and CMM if possible).
- Photograph the control panel and parameters before disassembly.
- Negotiate based on inspection findings: mechanical wear, control age, and spindle hours.
- Budget 10-20 % of purchase price for commissioning and possible refurbishment.
