Unformatted text preview: s describe where the holes are to be Frame contains tolerance for the holes Frame is actually "feature control frame" Used for holes, slots, tabs, surfaces, etc. Controls features & gives instructions
13 Feature Control Frame 1st compartment Geometric symbol 2nd compartment Zone symbol diameter, etc. Total tolerance Feature modifier 14 Feature Control Frame 15 GD&T Tolerance Zones 16 Datums Measurement origins used implied datums in past Edge of a part, etc. GD&T uses specified datums next compartments Need to know the order Measurements are basic no tolerance Tolerance in feature control frame with other requirements Placed under feature being located or controlled 17 18 Maximum Material Condition Concept Increases available tolerance Smallest hole or largest pin 19 Maximum Material Condition Concept 20 Maximum Material Condition Concept 21 22 Maximum Material Condition Concept Can give more tolerance while ensuring functional fit Was not available with plus/minus system MMC used most often (90%) Most parts are loose fitting Allows functional type gaging Used with location, form or orientation tolerances Modified features must have size
23 Least Material Condition Concept 24 Least Material Condition Concept 25 26 Least Material Condition Concept Used in unique situations such as: Controlling wall thickness Castings Gaging Tooling Least used method (5%) Used with location, form or orientation tolerances Modified features must have size (same as MMC)
27 Regardless of Feature Size Tolerance only as indicated in feature control frame No additional tolerance as in MMC...
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- Spring '08
- Datum reference, Geometric Characteristic Symbols