The principle of independence according to DIN EN ISO 8015 applies, deviations from this principle (e.g. envelope condition) must be agreed between the contracting parties.
Shaped part drawings or CAD data sets correspond to the nominal geometry. The tolerances are given as limit dimensions symmetrically to the nominal geometry. Asymmetrical tolerances of size dimensions (e.g. fitting dimensions) must be converted into a symmetrical tolerance field position by formal nominal dimension modification to the tolerance center dimension: 100-0.6 → 99.7 ± 0.3.
The verification of the part with regard to quality assurance must be clearly defined. The measuring concept is particularly important for parts that are not dimensionally stable, see also DIN ISO 10579.
Unless otherwise agreed, moulded parts may not be automatically rejected if the general tolerances are not complied with, provided the function is not impaired.
Constructively specified inclination differences due to draft angles are not part of dimensional tolerances or deviations in shape and position. In the specification, measurement points must be defined for function dimensions on inclined surfaces in order to define two-point dimensions.
To specify radii, at least 90° of the circle segment must be available as a measurable contour. Alternatively, radii can be tolerated by profile shape tolerances.
Freeform surfaces shall be specified with a profile shape tolerance. Verification shall be agreed
Directly tolerated angles and edges are subject to agreement. All angles and edges not directly tolerated are to be neglected during verification.
Separating crest, tool offset and their combination must be agreed with regard to the position of the separating lines between the customer and the manufacturer of the moulded parts.
With regard to the tolerance analysis of dimensional chains, it should be noted that the usual procedures require the rigid body. For plastic moulded parts, this condition is usually not sufficiently fulfilled due to the low stiffness of the moulding material and the distortion.