I. Observe workpiece placement and operating habits (usage behavior)
Long-term off-center loading often stems from improper operating methods:
1. Workpieces concentrated in one area: For example, consistently clamping and welding on the left side or slightly forward of the center of the worktable leads to excessive local stress.
2. Heavy components under unilateral loading: Large or heavy welding parts are frequently fixed in one module area without rotating different areas of the worktable.
3. Asymmetrical fixture layout: Fixtures are concentrated in a few hole groups, applying uneven clamping forces over a long period.
If the above situations persist, even if the total load is not exceeded, it may cause local stress concentration, resulting in de facto off-center loading.
II. Inspect the surface condition of the worktable (physical traces) Off-center loading will leave identifiable physical traces on the worktable surface:
1. Severe localized wear: Deformation of hole openings, increased edge burrs, or significant peeling of the anti-spatter coating in certain areas.
2. Visible changes in flatness: Slight concavity, warping, or noticeable gaps when a ruler is used for inspection.
3. Loosening at module connections: Long-term uneven loads may cause loosening of bolts connecting modules or wear of locating pins.
Pay special attention to the disruption of the uniformity of the gridded holes; this is an important visual clue for judging off-center loading.
III. Periodic Accuracy Inspection and Data Analysis (Measurement Basis) The most reliable method of judgment is periodic inspection using professional instruments:
1. Laser flatness measurement: Every 3-6 months, use a laser interferometer or 3D scanner to check the overall flatness of the table surface and compare it with historical data.
2. Module height difference comparison: Use a height gauge to measure the relative height of modules in different areas; a deviation exceeding 0.05mm/m warrants attention.
3. Stress release test: After placing the workbench in a standard environment for 7 days, retest. If the flatness changes spontaneously, it indicates internal stress imbalance, possibly caused by off-center loading.
