Spot welding machines are a type of welding process that uses the heat generated by resistors as the power source. After spot welding, the product quality still lacks reliable non-destructive testing methods at the current stage, and can only rely on visual inspection and destructive testing for inspection.

1. Visual inspection: Process testing is conducted to examine the feasibility of exploring process methods, process parameters, or the processability of materials.

2. Destructive testing: According to standards and regulations, tests are conducted on products or welded workpieces until they are destroyed. The properties of metals are crucial for metals or welds, so their accurate values must be determined.

3. Non-destructive testing methods: Non-destructive testing includes the following three types: (1) visual inspection; (2) leak tightness testing or pressure resistance testing; (3) non-destructive testing. Non-destructive testing is a way of examining and testing the internal and surface structure, characteristics, and conditions of samples without damaging them using physical or chemical methods, relying on expertise and machinery and equipment.