Fresh lifehacks

What is LMC tolerance?

What is LMC tolerance?

Definition: Least material condition is a feature of size symbol that describes a dimensional or size condition where the least amount of material (volume/size) exists within its dimensional tolerance.

How does LMC determine position tolerance?

Now calculate bonus tolerance = ( LMC Diameter – Actual Diameter ) = (4.20 – 4.10) = 0.10. Total acceptable Position Tolerance = Given TOL + Bonus TOL = 0.25+0.10 = 0.35. Actual Position 0.30 is less than acceptance total tolerance 0.35 therefore part is now accepted.

What is maximum bonus tolerance?

In GD, bonus tolerance is a modification of a GD tolerance that under certain conditions increases the tolerance, hence the term “bonus”. More specifically, when the maximum material condition (MMC) symbol is used to modify a GD tolerance, bonus tolerance becomes available.

How do you calculate MMC and LMC?

For an feature of size specified at MMC, Resultant Condition = LMC + Geometric Tolerance allowed. This is a single tolerance and size event.

Is there bonus tolerance at LMC?

Bonus tolerance explained: As the size of the pin departs from MMC toward LMC, a bonus tolerance is added equal to the amount of that departure. Bonus tolerance equals the difference between the actual feature size and the MMC of the feature.

Why is MMC LMC needed?

Reason for Use: If you want to ensure that two parts never interfere, or limit the amount of interference between the parts when they are at their worst tolerances, MMC can be called out. Take a shaft that must go through a hole with clearance between the two.

How does bonus tolerance work?

Bonus tolerance equals the difference between the actual feature size and the MMC of the feature. In this case, Bonus Tolerance = MMC-LMC=25-15=10.

What is bonus tolerance Why is it important?

Bonus tolerance is a important concept in GD. Bonus tolerance will be available for the geometric dimensioning and tolerancing feature of size with MMC or LMC modifiers. The bonus tolerance reduces the number of rejected parts by increasing the tolerance zone.

What is the difference between MMC and LMC?

MMC is the condition of a feature which contains the maximum amount of material, that is, the smallest hole or largest pin, within the stated limits of size. LMC is the condition in which there is the least amount of material, the largest hole or smallest pin, within the stated limits of size.

Can a form tolerance override Rule 1?

Also note that rule #1 can be overridden by either the Independency symbol or by a note stating that perfect form at MMC is not required. But with the Independency symbol, the part is allowed to violate the MMC boundary. The part is still always required to stay within the required size limit everywhere on the part.

Share this post