In CNC precision machining, benchmarking is the key basis for ensuring the dimensional accuracy and assembly performance of parts. It mainly includes the following four principles:

Design Basis

The starting points (such as axis lines and symmetrical planes) marked on the drawings determine the theoretical accuracy requirements of the parts.

Process benchmark

The positioning surface or measurement reference used during processing should coincide with the design reference as much as possible to avoid error accumulation.

Assembly reference

The mating surfaces of parts during final assembly (such as mounting holes and joint surfaces) directly affect the functional realization of the product.

Testing standards

The reference features used during quality inspection (such as three-coordinate measuring points) must be consistent with the design benchmark to ensure inspection accuracy.

Core principle: The four benchmarks should be unified as much as possible to reduce error propagation and ensure machining accuracy and assembly reliability.