Deck 3: Coordinate Tolerancing and Geometric Dimensioning and Tolerancing GDT

Question 1

What are the four benefits GD&T provides to an organization?

Answer 1

GD&T provides four important benefits to an organization:
1. Improves Communication: GD&T can provide uniformity in drawing specifications and interpretation, thereby reducing controversy, guesswork and assumptions. Design, production, and inspection all work in the same language.
2. Provides Better Product Design: The use of GD&T can improve your product designs by providing designers with the tools to "say what they mean," and by following the functional dimensioning philosophy.
3. Increases Tolerances for Production: There are two ways tolerances are increased through the use of GD&T. First, under certain conditions, GD&T provides "bonus"-or extra-tolerance for manufacturing. This additional tolerance can make a significant savings in production costs. Second, by the use of functional dimensioning, the tolerances are assigned to the part based upon its functional requirements. This often results in a larger tolerance for manufacturing. It eliminates the problems that result when designers copy existing tolerances, or assign tight tolerances, because they don't know how to determine a reasonable (functional) tolerance.
4. Lowers Costs: The result common to each of the first three benefits is lower costs for manufacturing and inspection of the part.

Question 2

Geometric tolerancing eliminates the shortcoming of square or rectangular tolerance zones by providing ____________________ tolerance zones.

Answer 2

cylindrical

Question 3

Explain three of the potential consequences of coordinate tolerances.

Answer 3

Three of the potential consequences of coordinate tolerances are:
1. Increased manufacturing costs: Due to the square (or rectangular) and fixed-size tolerance zones, the part manufacturing costs may be higher. The rejection of usable parts may also increase manufacturing costs.
2. Part acceptance disputes: As a result of several different possible interpretations where coordinate tolerances are used to locate or orient a diameter, width, or surface, there is a significant chance of two inspectors getting different measurements for a dimension on the same part. This can result in disputes over part acceptance.
3. Assembly problems: Where coordinate tolerances are used to locate or orient diameters, widths, or surfaces, there is a risk of non-functional parts. For example, parts measured with different setups may not assemble.

Question 4

It is faster to dimension a part with coordinate tolerancing than with GD&T.

Question 5

A coordinate tolerance uses a single-ended dimension line.

Question 6

When should coordinate tolerances be used?.

Question 7

One way geometric tolerancing eliminates the shortcoming of no measurement origin indication is by using a profile tolerance to relate the measurement to a reference (or datum) plane.

Question 8

Geometric tolerancing eliminates the shortcoming of undefined measurement setup by using a concept called "____________________" that allows the designer to define the measurement setup for the inspector.

Question 9

List the six major shortcomings of coordinate tolerancing.

Question 10

____________________ is a dimensioning approach that defines a part based on the product requirements.

Question 11

Coordinate tolerancing is an oversimplification of part definition and can actually raise costs.

Question 12

Geometric tolerancing eliminates the shortcoming of the exact start point of dimensions not being defined by using basic dimensions and profile callouts.

Question 13

Describe the use of an MMC modifier.

Question 14

____________________ is a symbolic language used on engineering drawings and CAD models to define part geometry and allowable variation.

Question 15

____________________ is a dimensioning system where the coordinates (X,Y,Z) of holes, diameters, and surfaces are located (or defined) by means of linear dimensions with plus-minus tolerances.