What is datum modifier?

When an (M) modifier is used in the geometric control frame along with a datum letter, the datum axis or the datum center-plane is established by the axis or the center-plane of true gage surface at the WCB of the feature-of-size.

What is a material modifier?

Material modifiers help the designer to better describe what is dimensionally acceptable by providing insight into additional tolerances caused by the presence or absence of material on a part or feature.

What does MMC on Datum mean?

maximum material condition
When the “M” is next to the tolerance for the feature its MMC ( maximum material condition ). When the “M” is next to the DATUM in the Feature control frame its MMB ( maximum material Boundry ).

What is maximum material modifier?

Maximum Material Condition: This is the condition where a feature has the maximum amount material possible. Examples being the smallest hole size, or the largest pin diameter. Least Material Condition: This is the exact opposite of MMC, a feature has the least amount of material possible.

What is U modifier GD?

In GD, unequally disposed tolerance is indicated by an encircled capital letter “U”. The unequally disposed symbol is shown after the total tolerance number in the feature control frame as shown in Figure 2 below. This means that the number to the right is “adding material”.

Why modifier is used in GD?

Use material condition modifiers in GD measurements to specify how the tolerance zone is affected by other tolerances that apply to a feature or datum feature.

What is P modifier in GD?

“P” stands for “projected tolerance zone.” This symbol indicates the tolerance applied to the protrusion of a feature.

What is Max material boundary?

The maximum material boundary concept is simply the use of a maximum material condition on a datum feature, as shown in Figure 1 (the annotation B(M)). A part with datums that have been assigned material modifiers, or that has less than 3 datums, can generally be considered to be underconstrained.

Which modifier is the most expensive?

59 Modifier
59 Modifier – most expensive.

What is S in GD?

Tolerance Zone Size Modifiers. Tolerance Zone Mobility Modifiers. (S) encodes the “aiming” or “centering” function of a feature and causes the tolerance. to be (S)tuck at the specified value.

When to use the m modifier on a datum?

In its function, if the datum feature is a clearance fit, and a little looseness or play is acceptable, then the M modifier should follow that datum letter when referenced. If the function dictates that the datum feature will be firmly held, like a press-fit dowel/hole, then the RFS condition is the way to go.

How are material condition modifiers used in GD & T?

Use material condition modifiers in GD measurements to specify how the tolerance zone is affected by other tolerances that apply to a feature or datum feature. For example, when a feature is designed to be fitted with another feature, such as a pin or a hole, the tolerances for the size and position affect the result.

When to use maximum or least material modifier?

Note: For datum features, material conditions are referred to as material boundaries. When you select a maximum or least material modifier, PowerInspect uses a bonus to increase the tolerance, depending on the feature’s accuracy.

When is a cylinder used as a datum feature?

“When a cylinder…is used as a datum feature, any feature control frames that reference the datum feature must include the material condition (MMC, LMC, or RFS) under which the datum feature simulator is to be constructed.” At any rate, one of those three is needed because a FOS can, of course, change in size from part to part.