Smart Investment Checklist: Key Factors Before Buying a Pre-Owned, Used, Surplus, Second-Hand DMG DMC 835 V CNC Vertical Machining Center made in Germany
Here’s a Smart Investment Checklist you can use before buying a pre-owned, used, surplus DMG DMC 835 V CNC Vertical Machining Center (Made in Germany). This covers machine condition, specs, service history, and risk-assessment factors you should verify before purchase.
1) Machine Identity & Specifications
Before anything else, confirm the machine’s authentic identity, capabilities, and build quality.
| Specification | What to Confirm |
|---|---|
| Model & Make | DMG DMC 835 V (Germany) |
| Machine Type | 3-axis / 3+2 / 5-axis configuration (confirm actual model details) |
| Table Size | Verify documented table length & width (e.g., ~1000 × 830 mm) |
| Travel Distances | X, Y, Z strokes — check actuals vs catalogue |
| Spindle Type / Power | Check RPM range, power rating, taper type |
| Control Unit | Siemens / Heidenhain / Fanuc version installed |
| Feedback Devices | Linear scales / encoder types |
Why this matters: Specs determine whether the machine can handle your parts and production requirements. A mismatch here is the biggest cause of regret.
2) Condition of Structural & Mechanical Systems
A used DMG can still be a winner — if the mechanical health is intact.
Spindle & Bearings
- Listen for unusual noises during acceleration/deceleration
- Measure runout and check for vibration on multiple RPM points
- Inspect taper & drawbar condition
Ball Screws & Guideways
- Check axial play & backlash in all directions
- Look for uneven wear, scoring, corrosion, or replaced parts
- Confirm lubrication system working properly
Ways & Surfaces
- Look for evidence of:
- Black oxide formation
- Scoring or dents
- Inconsistent wear patterns
3) CNC Control & Electronics
The CNC system is critical for long-term reliability.
Control Cabinet
- Check for dust buildup, oil, moisture
- Inspect fans, filters, cables, and fuse condition
- Verify all boards seat properly, no blown capacitors
Control Software & Hardware
- Confirm version of CNC power package (software installed)
- Ask for backup or machine parameter files
- Check for:
- Hard key security devices
- Available spare boards
Feedback & Sensors
- Encoder feedback
- Probe support
- Tool length measurement interface
4) Axis Drives & Motors
Wear or replacement of these is expensive.
- Run all axes slow → fast → reverse
- Listen for rhythm irregularities
- Verify servo amp health (temperature / sporadic faults)
- Ask for drive power consumption history if available
5) Hydraulic & Pneumatic Devices
Many used machines show wear here.
- Test tailstock actuation (if present)
- Inspect hydraulic lines for leaks
- Check accumulators, valves, and filters
6) Spindle Power & Torque Performance
Good condition spindles significantly affect performance and surface finish.
- Confirm rated power & torque verification (test cutting if possible)
- Check any coolant or spindle seal leaks
7) Machine History & Usage
The machine’s background tells you the risk profile.
Ask for:
- Total working lifetime or hours
- Feed-hold & emergency stop history
- Reason for sale
- Previous service logs
Older machines with detailed service documentation are far easier to support and maintain.
8) Maintenance & Wear Parts
Verify replacement of:
- Ball screws
- Guideway wipers
- Bearings
- Servo motors
- Spindle seals
Also check:
- Coolant quality & sump condition
- Chips and coolant drainage system
- Filters and lubrication status
9) Tooling & Fixtures
Often overlooked but highly valuable.
- Verify included CNC tool holders (BT / CAT / HSK, type)
- Fixtures, vices, soft jaws, collets
- Probes and calibration tools
These add immediate production value.
10) Operational Test
Never buy without running the machine under real work conditions.
Run tests including:
- High-speed rapid movement
- Various feed rates
- A simple part program
- Full depth cuts
- Check thermal stability
11) Geometric Accuracy Check
Ask for:
- Laser interferometer report
- Ballbar measurement results
- Squareness & straightness reports
These define actual viable precision.
12) Safety & Compliance
Ensure:
- Guards and covers intact
- E-stop functions properly
- Safety interlocks and doors working
- Compliance with your local electrical & safety standards
13) Warranty & Support
Used machines rarely have formal warranty, but check for:
- Remaining dealer warranty
- Transferable service contracts
- Available parts inventory
This reduces long-term repair risk.
14) Cost Breakdown
Don’t evaluate price alone — calculate total investment:
| Cost Item | Estimate |
|---|---|
| Purchase Price | $ |
| Delivery / Rigging | $ |
| Installation / Leveling | $ |
| Power / Air Setup | $ |
| Control Training | $ |
| Spare Parts Kit | $ |
| First-year Maintenance | $ |
15) Resale & Future Value
Consider:
- Brand resale rates (DMG generally holds value)
- Control standardization in your facility
- Availability of upgrades (e.g., 4th/5th axis, probing package)
16) Final Go/No-Go Questions
Ask yourself:
- Will this machine profit after all costs?
- Can it do the work you need reliably?
- Is it serviceable in your region?
- Does it have documented history?
Summary Recommendation
A well-maintained DMG DMC 835 V with documented service history, solid mechanical condition, and verified CNC control health is a strong investment. But remember:
Machine is only as good as its condition and documentation.
