How do I check the used newway?

Author:J           Date:2025-11-05

Core Principle: Avoid subjective assumptions and rely on objective testing.

Step 1: Static Precision Inspection

Macro Appearance and Structure: Observe the entire used newway, looking for signs of structural damage. Inspect major components such as the bed, column, and crossbeam for cracks, weld repair marks, or severe corrosion. Oil and dust can be cleaned, but structural damage is fatal.

Core Transmission Components: This is the most important part of the inspection. Open the protective cover and, ensuring power is off, carefully inspect the entire length of the guide rails and ball screw with a flashlight.

Guide Rails: Check for severe scratches, wear dents, or "steel sticking." Areas with frequent table movement usually experience the most wear.

Screws: Check for indentations and corrosion. Try turning the screw by hand (in a specific mode) to feel for noticeable axial play or jamming. Any discomfort means high repair costs.

Hydraulic and Lubrication Systems: Check the hydraulic and lubrication oil tanks for cleanliness and the presence of metal debris or emulsification. Blockages in the oil lines can lead to catastrophic wear.

Step Two: Dynamic Performance Testing

Idle Run and Abnormal Noises: Start the machine tool and run the X, Y, and Z axes at low to high speeds across their full stroke range. Carefully listen for any abnormal impacts, friction, or sharp noises from the drive motor, gearbox, and lead screw bearings. A smooth, low-pitched sound is normal.

Spindle Performance Testing: The spindle is the "heart" of the machine tool.

Gradual Speed ​​Increase: Run the spindle gradually from low to maximum speed, observing vibration and noise levels. Note any resonance at specific speeds.

Warm-up Test (Critical): Allow the spindle to idle continuously at its usual high speed or maximum speed for at least 30 minutes. Immediately afterwards, use an infrared thermometer to measure the temperature rise at various points on the spindle bearing housing. Excessive temperature rise or a final temperature exceeding 60-70°C strongly indicates bearing wear or poor lubrication, resulting in extremely high repair costs. Functional Testing: Test the automatic tool changer (ATC) process one by one to ensure smoothness, accuracy, and impact-free tool changing; test all auxiliary functions such as coolant, lighting, and air pressure to ensure they are functioning properly.

Step 3: Trial Cutting

After confirming that the static and dynamic checks are correct, a trial cutting test must be performed.

Heavy Cutting Test: Select a steel workpiece and perform milling with a large depth of cut and high feed rate to test the rigidity and power of the used newway, observing for any vibration or machine stoppage.

Finishing Test: Finish mill a plane or a square cavity, then use a dial indicator, micrometer, or coordinate measuring machine to check the workpiece's flatness, perpendicularity, actual positioning accuracy, and repeatability. This is the sole standard for verifying the machine tool's overall accuracy.

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