What is the national standard for the size tolerance range of automobile injection parts?

What is the national standard for the size tolerance range of automobile injection parts?

The national standard for the size tolerance range of automotive injection parts is GB/T 14486-2008 “Plastic molded Parts Size Tolerance”. This standard specifies the dimensional tolerances of plastic moulded parts, and is suitable for plastic moulded parts that are injected, pressed and injected.

According to the national standard, the size tolerance range of automotive injection parts is divided into A and B grades. Class A precision requirements are high, suitable for precision injection parts; Grade B precision requirements are low, suitable for general injection parts. The specific tolerance range is as follows:

(1) Linear dimensional tolerance:
Linear dimensions refer to dimensions along the length. For Class A injection molded parts, the tolerance range of linear size is ±0.1% to ±0.2%; For Class B injection molded parts, the tolerance range for linear dimensions is ±0.2% to ±0.3%.

(2) Angle tolerance:
Angle tolerance refers to the Angle deviation in shape and position tolerance. For Class A injection molded parts, the Angle tolerance is ±0.2° to ±0.3°; For Class B injection molded parts, the Angle tolerance is ±0.3° to ±0.5°.

(3) Form and position tolerance:
Form and position tolerances include roundness, cylindricity, parallelism, verticality, etc. For class A injection parts, form and position tolerances are given according to class K in GB/T 1184-1996 “Shape and Position Tolerances not specified Tolerance Value”; For class B injection parts, form and position tolerances are given according to class M in GB/T 1184-1996.

(4) Surface roughness:
Surface roughness refers to the degree of microscopic unevenness on the machined surface. For class A injection molded parts, the surface roughness is Ra≤0.8μm; For class B injection molded parts, the surface roughness is Ra≤1.2μm.

In addition, for some special requirements of automotive injection parts, such as instrument panels, center console, etc., the dimensional tolerance requirements may be higher, and need to be controlled according to specific product requirements.

In short, the national standard for the scope of dimensional tolerance of automotive injection parts is GB/T 14486-2008 “Dimensional tolerance of Plastic molded parts”, which specifies the requirements of dimensional tolerance, shape and position tolerance and surface roughness of plastic molded parts. In actual production, it is necessary to adjust and optimize according to product requirements and mold design to ensure that the automobile injection parts meet the requirements.