I. Core Judgment Standard: Flatness Tolerance
Ordinary Grade Table: Flatness <= 0.15mm/1000mm, suitable for general welding and assembly scenarios.
Precision Grade Table: Flatness <= 0.10mm/1000mm, commonly used in high-requirement processes such as automotive parts and robotic welding.
High-Precision Grade Table: Flatness <= 0.05mm/1000mm, used in aerospace, precision molds, and other fields where the reference surface is extremely sensitive.
✅ Reputable manufacturers should provide a coordinate measuring machine (CMM) inspection report at the time of shipment, which can be used as the acceptance basis. If the measured value exceeds the above standards, it is judged as substandard.
II. Commonly Used Inspection Methods and Operating Points
Optical Image Level Method (Recommended for On-Site Use)
Suitable for on-site inspection of medium and large-sized tables.
Calculation Method (High-Precision Laboratory Testing): Draw a grid along the platform (e.g., one measuring point every 200mm). Use an electronic level with an accuracy of 0.02mm/m to measure the tilt value point by point. Convert the measured value to height difference, fit it to an ideal plane, and calculate the maximum deviation.
Coordinate Measuring Instrument Method (High-Precision Laboratory Testing) Collect the three-dimensional coordinates of hundreds of points using a probe. The software automatically fits a reference plane and outputs flatness data. At least 50 measurement points should be evenly distributed. Results are traceable and reports can be exported.
Laser Interferometer Method (Ultra-High Precision Testing) Non-contact scanning utilizes the principle of laser interferometry to analyze surface undulations. Suitable for acceptance or calibration of high-precision platforms requiring <=0.05mm/1000mm, with an accuracy of ±0.001mm.
Dial Indicator + Reference Plate Comparison Method (Simple and Rapid Comparison) Place the worktable on a high-precision reference plate. Fix the dial indicator with a magnetic base and measure the height difference between the platform and the reference plane point by point. Suitable for quickly determining whether local deformation has occurred on small to medium-sized platforms.
III. Simple On-Site Judgment Techniques (No Professional Equipment Required)
Knife-Edge Ruler Light Transmission Method: Place a knife-edge ruler against the table surface and observe the light transmission through the gaps. A noticeable gap or an arc shape indicates a localized bulge or depression.
Standard Pin Insertion Method: Insert a standard locating pin into an adjacent hole. If it is too tight or there is significant wobbling, the hole system may be misaligned due to planar deformation.
Right-Angle and Feeler Gauge Inspection: Use a right-angle ruler against the side and a feeler gauge to measure the gap. If the gap is >0.1mm within a 200mm height, the verticality is out of tolerance, indirectly reflecting a misalignment of the planar reference.
⚠️ Note: These simple methods are only for preliminary screening; final confirmation requires professional instruments.
IV. Key Prerequisite for Compliance: Platform Quality Assurance
Materials and Processes: HT300 high-strength cast iron is used, treated with artificial annealing and vibration aging to eliminate internal stress and prevent natural deformation during use.
Surface finishing method: High-precision platforms require one-time precision milling on a gantry milling machine or manual scraping to ensure uniform contact points (no less than 20 points per 25×25mm²).
Structural design: A "well"-shaped reinforcing rib is provided at the bottom to improve rigidity and prevent deflection under load.
