ISO 2692-2021 pdf free download – Geometrical product specifications (GPS) — Geometrical tolerancing — Maximum material requirement (MMR), least material requirement (LMR) and reciprocity requirement (RPR).
4.1.4 MMR or LMR applied to several toleranced features
When an MMR or LMR applies to several toleranced features, the symbols CZ or SZ shall always beindicated in the zone section of the tolerance indicator following the sequence order specified inISO 1101.
NOTESee Annex B for former practice.4.1.5Simultaneous requirement
A simultaneous requirement can be useful for example for MMR or LMR with same datum indicationcontaining MMR or LMR.
When a simultaneous requirement is needed, the SIM symbol possibly followed by an identificationnumber (SIMi) without a space shall be indicated in the adjacent indication area of each relatedgeometrical specification in accordance with ISO 5458.
The use of the SIM modifier transforms a set of more than one geometrical specification with MMRor LMR into a combined specification. The corresponding MMVC or LMVC are locked together withlocation and orientation constraints according to the rules of this document. T’he datum system is alsoconstrained to be the same for each specification in the same SIM group.
Figure A.17 shows an example of simultaneous requirement.
4.1.6MMR or LMR on a datum without MMR or LMR on the toleranced feature
When an MMR or LMR is applied to the datum only (see Figure A.19), then the rules for datum fullyapply (see 4.2.2,4.2.4 and 4.3.2,4.3.4). n addition, the constraints on the MMVC(s) of the datum(s] andthe MMVC(s) of the toleranced feature(s) stated in rule D [see 4.2.1 d)] or in rule K (see 4.3.1 d)] arereplaced with the corresponding constraints applied on the MMVc(s) of the datum(s) and the tolerancezone as defined in ISo 1101 and IsO 5459.
4.2Maximum material requirement (MMR)
4.2.1MMR for toleranced features with indirect determination of virtual size
When the MMR applies to the toleranced feature and the indirect determination of virtual size isselected, it shall be indicated on drawings by the symbol Mplaced after the geometrical tolerance ofthe derived feature of the feature of linear size (toleranced feature) in the tolerance indicator with nosize indicated in square brackets.
The MMR for toleranced features with indirect determination of virtual size results in four independentrequirements:
-a requirement for the upper limit of the size [see rules A 1) and A 2)];- a requirement for the lower limit of the size [see rules B 1) and B 2])J];-a requirement for the surface non-violation of the MMVC (see rule C);-a requirement for applying constraints on MMVCs (see rule D).
When the MMR is specified for the toleranced feature with indirect determination of virtual size, thenthe following rules shall be applied for the surface(s) (of the feature of linear size), and the MMVS shall be computed from the size specification and the geometric specification according to the rules of thisdocument.
a) Rule A: The sizes of the toleranced feature shall be:
1)equal to or smaller than the MMS, for external features;2)equal to or larger than the MMS, for internal features.
NOTE1 This rule can be altered by the indication of RPR, with symbol Rafter the symbol M[see 5.2and Figure A.1 b)].
b)Rule B: The sizes of the toleranced feature shall be:
1) equal to or larger than the LMS, for external features [see Figures A.2 a),A.3 a),A.4 a), A.6 a),A.7 a),A.10,A.11 and A.12];
2) equal to or smaller than the LMS, for internal features [see Figures A.2 b),A.3 b),A.4 b),A.6 b),A.7z b),A.10 to A.13,A.16 to A.19].
c)Rule C: The MMVC of the toleranced feature shall not be violated by the extracted (integral) feature (see Figures A.2,A.3,A.4,A.6,A.7,A.10 to A.19).ISO 2692 pdf download.