What is a virtual condition?
What is a virtual condition?
Virtual Condition is defined as the boundary generated by the collective effects of the specified MMC limit of size of a feature and any applicable geometric tolerance. For example, the MMC size of a shaft plus its axial Straightness tolerance, or the MMC size of a hole minus its Position tolerance.
How is virtual condition calculated?
Virtual Condition = Tolerance boundary that is constant for all sizes and generated by the cumulative effects of size and geometric tolerance at MMC. For an external feature of size with MMC specified, Virtual Condition = MMC + Geometric tolerance, or as-manufactured size + allowed geometric tolerance at that size.
How does GD calculate virtual conditions?
The calculations for the Virtual Condition are shown below:
- Virtual Condition (internal feature) = MMC (smallest size) – Geometric Tolerance.
- Virtual Condition (external feature) = MMC (largest size) + Geometric Tolerance.
- Inner Boundary @ RFS = Smallest Feature Size – Geometric Tolerance.
Why virtual condition is used?
The Virtual Condition of a feature is a concept used to describe the worst-case envelope which either of two features must lie within in order to mate acceptably. For a shaft that fits into a hole, the shaft virtual condition must be smaller than the hole virtual condition.
What is virtual size GDT?
Geometric Dimensioning & Tolerancing GD Definitions Virtual Condition (Size) – The boundary generated by the collective effects of MMC, size limit of a feature and any associated geometric tolerance, virtual condition must be considered in determining the fit between mating parts.
What is maximum material condition for hole and pin?
Maximum Material Condition (MMC) and Least Material Condition (LMC): Simple Definitions. 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.
Under what conditions is Rule #1 not applicable?
Rule #1 does not apply to a FOS on a part subject to free-state variation in the unrestrained condition. In simple terms, Rule #1 does not apply to flexible parts that are not restrained.
What is the virtual condition of the boss?
Virtual condition is the theoretical extreme boundary condition of a feature of size generated by the collective effects of MMC and any applicable geometric tolerances. 4 and a straightness tolerance 0.1 is specified at MMC. Which means that our extreme boundary is 20.5 and which is the virtual condition.
What is MMC condition?
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.
What are the material conditions?
The aspects of a period of time that influence a person’s lived experience such as: the modes of production; the quality and quantity of materials available and accessible to individuals; and the morals, customs and laws that delineate the proper use and trade of said materials.
What is maximum material condition example?
In GD, maximum material condition (MMC) refers to a feature-of-size that contains the greatest amount of material, yet remains within its tolerance zone. Some examples of MMC include: Largest pin diameter. Smallest hole size.
When a feature is controlled with the Maximum Material Condition (MMC) modifier or Least Material Condition Modifier (LMC), a size boundary is created based on the collection of geometric and size tolerances. This boundary is the actual maximum envelope that a part can be within and maintain specification. This is called the Virtual Condition.
What is virtual condition in GD?
Virtual Condition – GD. Virtual condition is the theoretical extreme boundary condition of a feature of size generated by the collective effects of MMC and any applicable geometric tolerances. Consider above example for better understanding of virtual condition.
What is the virtual condition of MMC?
Consider above example for better understanding of virtual condition. Here MMC is Ø20.4 and a straightness tolerance 0.1 is specified at MMC. Which means that our extreme boundary is 20.5 and which is the virtual condition.
How to calculate the virtual condition for feature size?
The virtual condition for this feature would be calculated as follows: Virtual Condition = Ø10.2 (size at MMC) + Ø0.2 (perpendicularity tolerance) = Ø10.4 As we depart from the Maximum Material Condition, we gain bonus tolerance. (Bonus tolerance is the difference between the actual feature size from the MMC.)