I. Material: The foundation determines stability
1. Cast Iron Platform: HT250 or HT300 high-strength cast iron is preferred. It has a bright surface, dense structure, high tensile strength, and good shock resistance. Inferior products often use HT150 or even a mixture of clay and iron slag, with a dark gray surface that is prone to deformation and cracking.
2. Steel Platform: Q345 low-alloy steel is recommended. It undergoes overall heat treatment to eliminate internal stress, providing good rigidity and weldability. Avoid using ordinary carbon steel such as Q235, as it is prone to corrosion and lacks sufficient strength.
3. Verification Method: Request a material report from the supplier and check if resin sand casting is used (superior to traditional clay sand), effectively reducing defects such as porosity and shrinkage.
II. Accuracy Check: Core Indicators Determine Positioning Reliability
High-quality 3D welding worktables must meet strict geometric tolerance standards:
Flatness: ≤0.1mm within a 1000mm length; high-end platforms can achieve ≤0.05mm/1000mm.
Hole Position Accuracy:
Hole Spacing Tolerance ≤±0.05mm
Hole Diameter Accuracy D10 or higher (e.g., φ28D10)
Hole Perpendicularity to Working Surface ≤0.1mm/1000mm
Surface Roughness: Working surface Ra≤3.2μm; precision grade can achieve Ra≤1.6μm.
It is recommended to conduct on-site spot checks of key hole spacing and flatness using a micrometer, dial indicator, or standard gauge bar. A coordinate measuring machine (CMM) measurement report should be requested if necessary.
III. Structural Inspection: Details Reflect Craftsmanship
1. Panel Thickness and Reinforcing Rib Design
High-quality platform panels are typically 30mm thick, with countersunk hole technology ensuring sufficient hole depth; inferior products are only cast to 25mm and directly drilled, resulting in insufficient strength.
The back should have a fully reinforced structure with reasonable rib thickness (recommended ≥30mm), evenly distributed to improve overall rigidity and resistance to deformation.
2. Support Leg Load-Bearing Capacity
Standard/Fixed Type: 2T load-bearing capacity
Lifting Type: 3T load-bearing capacity
Frame Type: Up to 5T, suitable for heavy workpieces
Universal Casters with Brakes: Easy to move, but lower load-bearing capacity (approximately 1T)
IV. Surface Treatment Inspection: Affects Durability and Maintenance Costs
1. Anti-Splash Treatment: High-quality platform surfaces undergo special coating or plating treatment, making it difficult for welding spatter to adhere and easy to clean.
2. Anti-corrosion process: Steel platforms can be chrome-plated (bright metallic color) or nitrided (black surface, hardness HV400 or higher) to enhance wear resistance and rust prevention.
Cast iron platforms require shot blasting and sandblasting followed by rust-preventive paint treatment to prevent paint peeling.
3. Grid line clarity: Grid lines should be clear, wear-resistant, and 100×100±0.05mm in size for easy and quick positioning.
V. Check the heat treatment process: Key to preventing later deformation
1. Reputable manufacturers will perform artificial annealing (600–700℃) + natural aging (2–3 years) double treatment on castings to completely eliminate internal stress and ensure long-term use without deformation.
2. If sufficient aging treatment is not performed, the platform may warp after a period of use, leading to inaccurate positioning.
VI. Simple on-site identification methods
1. Visual inspection: No sand holes, no weld repair marks, no oxide spots, and uniform edge chamfering.
2. Hole Spacing Measurement: Randomly measure the spacing between multiple adjacent holes using calipers. The deviation should be ≤0.05mm.
3. Module Trial Assembly: Insert the locating pins and clamps into different hole positions. The insertion should be smooth and without jamming. Repeated assembly should maintain consistent accuracy.
4. Stiffness Test: After applying a load, observe the deflection at the center of the platform. A high-quality platform should deflect no more than 1μm per 250N load.
