Purchasing a second-hand SCHULER hydraulic press can deliver exceptional value — if you perform the correct technical, mechanical, and documentation checks. SCHULER is among the most trusted German press manufacturers, but even the best machines can suffer from wear, misalignment, leaks, or improper modifications when not maintained correctly.

Use this guide to avoid the most frequent and costly mistakes.

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1. Confirm the Exact Machine Configuration

SCHULER’s HPX series often contains variations depending on:

• Table size (2.5 × 1.3 m in this model, but verify usable daylight and throat)
• Stroke length
• Number of cylinders
• Speed of approach/return
• Pressing cycle controls
• Tool clamping configuration
• Bed and ram design (monoblock or welded)

Why it matters: Machines labeled “HPX-400” may differ significantly based on previous customer specifications.

Avoid the pitfall: Request the original SCHULER order sheet, engineering drawings, and wiring diagrams.

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2. Inspect the Hydraulic System for Wear and Leakage

A 400-ton press relies heavily on the quality of its hydraulic components.

Check:

• Cylinder seals (look for oil film around the rod)
• Main cylinder chrome condition (pitting or scoring = expensive repair)
• Servo valves or proportional valves (Bosch Rexroth, Moog, etc.)
• Hydraulic pumps (gear/piston pump wear)
• Manifold blocks for internal leakage
• Pressure lines and fittings

Avoid the pitfall:
Cycle the press hot for 30–45 minutes to reveal pressure loss, internal bypassing, and overheating. A cold test hides major issues.

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3. Evaluate Frame Integrity and Parallelism

Even SCHULER presses can experience long-term frame deformation if overloaded.

Perform:

• Bed-to-ram parallelism measurement
• Column tension inspection (if column-type)
• Finite crack inspection on welds or casting corners
• Plate flatness measurement

Avoid the pitfall:
Only rely on readings taken with dial indicators or laser alignment equipment, not visual inspection.

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4. Examine the Control System and Electronics

Older SCHULER presses may use Siemens S5, S7-300, or S7-400 controllers.

Verify:

• PLC version and upgrade availability
• HMI operational condition
• I/O modules health
• Safety relay functions
• Presence of outdated or discontinued boards

Avoid the pitfall:
Replacing outdated PLC modules can cost more than the press itself. Ensure parts are still available or budget for modernization.

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5. Check the Hydraulic Power Unit (HPU) Thoroughly

Inspect:

• Oil tank condition
• Filters (pressure & return)
• Oil cooling system (water chiller or heat exchanger)
• Condition of accumulators
• Pump noise (indicates wear or cavitation)

Avoid the pitfall:
Dirty or burnt hydraulic oil indicates poor maintenance and accelerates wear on valves and pumps.

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6. Verify the Pressing Speed and Cycle Times

A used machine may no longer achieve factory cycle speeds due to:

• Pump wear
• Valve timing issues
• Internal cylinder leakage
• Weak accumulators

Avoid the pitfall:
Run the machine with a pressure and speed test sheet, comparing values to SCHULER factory specifications.

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7. Confirm Tool Clamping and Die Area Condition

Check:

• T-slot condition (cracks or deformation)
• Through-holes
• Surface flatness
• Any welding repairs or plate relining

Avoid the pitfall:
T-slot repairs on SCHULER frames can be extremely expensive and may reduce long-term accuracy.

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8. Validate the Safety Systems

A 400-ton press must comply with modern safety standards.

Inspect:

• Light curtains
• Two-hand control system
• Category 3 or 4 safety circuits
• Emergency stop modules
• Safety interlocks
• Door/guard switches
• Overload protection

Avoid the pitfall:
Missing safety components can delay installation and trigger expensive compliance upgrades.

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9. Review Maintenance Documentation & Usage History

Ask for:

• Full maintenance log
• Oil analysis reports
• Replacement parts receipts
• Any modernizations (electrical or hydraulic)
• Machine operating hours
• Real press usage (deep drawing, stamping, forming, etc.)

Avoid the pitfall:
Presses used in heavy deep drawing may have higher structural fatigue compared to those used in light stamping.

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10. Perform a Load Test Before Finalizing the Purchase

Always request:

• A full-tonnage pressure test (400 tons)
• A cycle test at full speed
• Measurement of holding-pressure stability
• Measurement of pressure drop over time

Avoid the pitfall:
Many sellers only demonstrate the machine at low tonnage, hiding cylinder wear or pump inefficiency.

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11. Get OEM Spare Parts Availability Confirmation

SCHULER spare parts availability varies depending on model age.

Check availability of:

• Seals
• PLC modules
• Valve blocks
• Pressure transducers
• Pumps
• HMI panels

Avoid the pitfall:
Budget for modernization if the electronic control system is obsolete.

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12. Conduct a Professional Third-Party Inspection

For a 400-ton SCHULER press, an expert mechanical + hydraulic inspection typically includes:

• Load testing
• Laser alignment
• Cylinder wear analysis
• Thermal imaging of electrical cabinet
• Pressure curve evaluation

Avoid the pitfall:
Skipping professional inspection is the #1 cause of unexpected post-purchase repair costs.

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Conclusion

A SCHULER HPX-400-2.5X1.3 is a high-precision, high-durability German hydraulic press. However, its complex hydraulic, mechanical, and electronic systems require thorough evaluation when purchasing second-hand. By checking the hydraulic system, control electronics, frame alignment, safety systems, and maintenance history, you significantly reduce risks and ensure a reliable, high-performing investment.