Structural Inspection Standard For ​Sheet Metal Parts
- Sep 18, 2018 -

Structural Inspection Standard For Sheet Metal Parts

1. Purpose

Standardize the structural inspection standards for sheet metal parts so that the process requirements and consistency of the product are effectively controlled

2. Scope of application

This standard is applicable to the inspection of various structures of sheet metal parts of the company, and the drawings and technical documents are used together. In case of conflict, the drawing requirements shall prevail.

3. Reference standard of inspection for sheet metal parts

The unlabeled dimensions of this standard are taken as mm, and the unfilled tolerances of sheet metal parts are executed according to the national standard IT13.


Limit and cooperation 

Standard tolerance and basic deviation value table

GB/T1800.4 -1998 

Limit and cooperation 

Standard tolerance class and limit deviation table for holes and shafts


General tolerance

Unfilled tolerance of linear and angular dimensions for sheet metal parts

Unfilled position tolerances are performed according to GB/T1184 –1996 unfilled value of shape and position tolerances

4. Raw material inspection standards (our company has the right to inspect the raw materials for the production of the factory)

4.1 Metallic material

4.1.1 The thickness and quality of the coffin shall comply with the national standard, and the coffin used shall be presented with a performance test report and manufacturer's certificate.

4.1.2 Material appearance: smooth and rust-free, no cracking and deformation.

4.1.3 Dimensions: Executed according to the drawings or technical requirements of sheet metal parts, our company has implemented according to the current national standard as well on unfilled requirement.

4.2 General hardware, fasteners for sheet metal parts

4.2.1 Appearance: no embroidered surface, no burr, and the appearance of the whole batch is consistent.

4.2.2 Size: According to the drawings and national standards.

4.2.2 Performance: trial assembly and performance meet product requirements.

5. Quality inspection standard for processing 

5.1 Blanking inspection standard

Deburring is performed on sharp corners, edges, and roughness that may cause injury.

Sharp corners (unless otherwise specified) not clearly indicated in the drawings are R1.5.

The burrs of sheet metal parts generated by the stamping process shall have no obvious defects such as protrusions, depressions, roughness, scratches and rust on the exposed visible surfaces of the door panels and panels.

Burr: After punching, the burr of sheet metal parts is high L ≤ 5% t (t is the thickness of the plate).

Scratch, knife mark: It is qualified to touch the hand without touching the hand, it should be ≤0.1.