How do I evaluate my Used STUDER?

Author:J           Date:2025-11-08

1. Mechanical Condition and Precision Retention (50% of total weight)

This is the cornerstone of the evaluation, directly determining whether the used STUDER can produce qualified products.

Bed, Guideways, and Slides: Inspect for wear, scratches, and corrosion. The precision of the guideways is the foundation of all precision. Manually move the slide to feel if it is smooth and stable, without any jamming.

Spindle System—The "Heart" of the Machine Tool:

Radial Runout and Axial Runout: These are mandatory indicators that must be measured. Use a dial indicator to measure at the spindle nose; the standard usually requires it to be within 1-2 micrometers (µm). A value exceeding 5 micrometers drops significantly.

Operating Status: Run the machine at rated speed without load, listening for smoothness, quietness, and any abnormal noises or vibrations. After running for a period of time, touch the spindle box to check if the temperature rise is within a reasonable range.

Feed System: Check for backlash in the leadscrew and bearings. The repeatability of the CNC axes is a key indicator.

Lubrication System: Ensure the automatic lubrication pump is functioning properly and that oil passages at all lubrication points are unobstructed.

2. Control System and Electrical System (25% of total weight)

CNC System Brand and Model: Such as Siemens, Fanuc, Bosch, etc. Mainstream, common systems (such as SINUMERIK 810D/840D) are more valuable due to technical support and a well-established spare parts market.

System Status: Power-on test for any alarms. Verify that all functions (such as axis movement, M-codes, cooling, grinding wheel dressing, etc.) are normal. Check the I/O interfaces for integrity.

Servo Drives and Motors: Check for smooth operation, vibrations, or overload alarms.

Electrical Cabinet: Open and inspect the wiring for neatness, overheating, modifications, or illegal wiring. The higher the degree of originality, the better.

3. Maintenance History and Documentation (15% of total weight)
This is the most easily overlooked but crucial "soft power."

Maintenance and Repair Records: Complete records (such as spindle overhaul, guide rail scraping, and lead screw replacement) greatly enhance equipment value because they demonstrate that the equipment has been carefully maintained and risks are manageable.

Operation, Programming, and Circuit Diagram Manuals: Complete original documentation is crucial for subsequent maintenance and troubleshooting.

Spare Parts List: Included spare parts (such as grinding wheel flanges, tie rods, and special tools) also have considerable value.

4. Overall Appearance and Working Environment (10% of total weight)

Appearance Condition: Check for intact paint, obvious dents, and rust. While this does not affect accuracy, it reflects the management level of previous users.

Internal Cleanliness: Inspect the inside of the protective cover and under the worktable for excessive wear debris and sludge. This reflects the equipment's maintenance status.

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