How to choose a used kent?

Appearance and Basic Structure:

Overall Condition: Observe the used kent appearance for signs of severe collisions, repairs, or corrosion. Minor paint wear is normal, but extensive corrosion may indicate improper maintenance or use in harsh environments.

Nameplate Information: Verify the model number, year of manufacture, and serial number on the nameplate to ensure they match the seller's description.

Mechanical Precision and Wear (The Core of the Core):

Guideway Wear: This is the main cause of precision loss. Feel the guideway surface (especially in frequently used travel areas) by hand for noticeable pits or steps. Use a dial indicator to check the straightness and tilt of the worktable movement.

Lead Screw and Backlash: Manually rotate the lead screw to check for smooth operation and any jamming. During automatic feed, measure the backlash with a dial indicator; excessive backlash will affect dimensional accuracy.

Spindle System:

Operating Status: Start the spindle under no-load and listen for smooth operation and any abnormal noises (such as the rumbling or knocking sounds of bearing wear).

Radial runout and axial runout: Use a dial indicator or micrometer to check the spindle's accuracy. This is the soul of the grinding machine; if the accuracy exceeds the standard, it must be repaired or the machine abandoned.

Temperature rise: After running for more than half an hour, touch the spindle box housing to see if the temperature rise is within a reasonable range. Abnormal overheating indicates bearing problems.

Hydraulic and lubrication systems:

Hydraulic system: Start the hydraulic pump and check if the reciprocating motion of the worktable is smooth and without crawling. Check the hydraulic tank and pipelines for oil leaks.

Lubrication system: Confirm that the automatic lubrication system is working properly, and that there is a fresh oil film on the surfaces of all guide rails and lead screws. Lack of lubrication is the main cause of machine wear.

Electrical and control systems:

Operation test: Test all operating buttons, handwheels, and emergency stop switches to ensure they function properly.

CNC system (if applicable): If it is a CNC grinding machine, check if the system starts normally and without alarms. Try executing simple movement commands to see if the servo motor response is normal.

Step 3: Trial Grinding Verification

If conditions permit, trial grinding should be performed. This is the final means of verifying overall accuracy.

Surface Grinding Machine: Grind a standard test block (such as cast iron or steel), then use a level, micrometer, or optical flat to check its:

Surface Finish: Whether it meets your process requirements.

Flatness: Check the overall flatness of the workpiece.

Parallelism: If grinding two opposite sides, check their parallelism.

Universal Grinding Machine: Trial grind a standard test bar and check its:

Roundness and Cylindricity

Surface Finish.