I. Identifying Deformation Type and Causes Based on Anomaly Characteristics
1. Overall Tilt (One End Higher, One End Lower)
Manifestation: Level measurement shows a continuous tilt in a single direction, without any sudden changes in local areas.
Causes: Uneven installation foundation, uneven stress on support legs, or improper tightening sequence.
✅ Can be resolved on-site with leveling; no professional processing required.
2. Central Protrusion or Edge Depression (Drum-shaped/Saddle-shaped Deformation)
Manifestation: The center or surrounding edges are significantly higher/lower than the surrounding area, exhibiting symmetrical undulations.
Causes: Release of internal stress, localized overheating during welding, or long-term unilateral load leading to plastic deformation.
❌ Cannot be leveled on-site; requires professional correction.
3. Localized Protrusions or Pits
Manifestation: Unevenness only appears near the weld or in a small area; other areas are flat.
Causes: Unrefined weld reinforcement, impact damage, or uneven welding.
✅ Can be partially repaired, avoiding overall machining.
4. Curved or Spiral Deformation
Manifestations: "Warping" along the diagonal, such as one corner being higher and the opposite corner lower.
Causes: Insufficient structural rigidity, improper handling, or uneven foundation settlement.
❌ Must be systematically corrected by the manufacturer.
II. Adjustment Methods and Operation Paths Based on Abnormal Characteristics
1. Overall Tilting → On-site Leveling
Tools: Electronic level with accuracy ≥ 0.02mm/m, wrench
Operation Procedure: Loosen all anchor bolts to release pre-tightening stress; Measure the tilt value at each point along a "rice" shaped path; Based on the "three-point plane" principle, prioritize adjusting the three main support points, making cross-fine adjustments until the bubble is centered; Tighten the fixing bolts evenly to prevent secondary deformation.
Target: Flatness restored to ≤0.10mm/1000mm (precision standard).
📌 Note: If the platform is equipped with an electronic leveling system, more precise fine-tuning can be achieved using the digital interface.
2. Center Protrusion/Edge Recess → CNC Precision Milling + Vibration Aging
Applicable Objects: Platforms with large-area minor deformation or after welding repair
Process Flow: First, vibration aging treatment is performed. The platform is vibrated in a resonant state using a vibrator to release residual stress.
Then, a gantry milling machine is used to perform overall precision milling of the working surface, aligned with the back reference surface, and machined in a single pass. A disc milling cutter is used; the feed rate and depth of cut need to be optimized according to the characteristics of HT300 cast iron.
Advantages: High efficiency; can quickly restore flatness to within 0.08mm/1000mm.
⚠️ Note: Weld excess material must be ground before precision milling to prevent tool damage; areas with varying hardness must be handled by experienced technicians.
3. Localized Bumps/Pits → Manual Scraping (Localized)
Applicable to: Localized repair of high-precision platforms (≤0.05mm/1000mm)
Operating Method: Apply red lead to a standard flat plate and rub against it to expose the bumps; Use a scraper to remove the bumps point by point, repeating the "rubbing-scraping" operation until uniform contact is achieved; At least 20 contact points are required per 25×25mm² area.
Advantages: Submicron level precision can be achieved, and the surface forms oil-retaining micro-pits, resulting in superior wear resistance.
✅ Recommendation: Used in applications requiring extreme precision, such as robot welding fixture reference tables and aerospace component assembly platforms.
4. Torsional Deformation → Mechanical Correction + Vibration Aging
Operation Method: Slowly apply pressure to the corners using hydraulic equipment to induce reverse plastic deformation; Apply pressure gradually to avoid material damage; After correction, allow to stand for 24-48 hours to prevent springback.
Cooperating Measures: Perform vibration aging treatment first to stabilize the internal structure and prevent re-deformation after repair.
📌 Recommended Combined Application: First, perform VSR to release stress → then mechanical correction → finally, fine milling or scraping the finish surface to achieve a dual effect of "treating the root cause + addressing the symptoms".
III. Key Verification Actions After Adjustment
Regardless of the method used, the following steps must be performed after adjustment:
Retest Verification: Re-inspect using a coordinate measuring machine or laser interferometer to ensure data meets standards;
Contact Spot Inspection: High-precision platforms must verify the point distribution using the red lead lapping method;
Establish Accuracy Records: Record data from each inspection and plot a "flatness change trend chart" for preventative maintenance.
⚠️ Special reminder: If you find that the fixture is stuck when plugging or unplugging, the positioning is off, or the weld is misaligned, you should stop using it immediately and check the flatness to prevent batch workpieces from being scrapped.
