GDTP Section 4 Datum and Datum Reference Frames (DRF)

GDTP stands for Geometric Dimensioning and Tolerancing Professional. It is a certification program offered by the American Society of Mechanical Engineers (ASME) that verifies an individual’s competence in understanding and applying the principles of Geometric Dimensioning and Tolerancing (GD&T). GD&T is an essential language used for clear communication in manufacturing, ensuring that designs are manufactured as intended. ASME’s Y14.5 Standard serves as the authoritative guideline for GD&T, and GDTP certification is based on either the 1994 or 2009 revisions of this standard, including its appendices and the application of its principles and practices. The certification program offers two levels of certification: Technologist and Senior.  This section is based on Chapter 4 of ASME STD. In this section, topics covered DATUM REFERENCING  including

(a) definitions

(1) datum simulator

(2) datum reference frame

(b) immobilization of part

(1) purpose — measurable relationships

(2) true geometric counterparts

(3) application

(4) datum reference frame

(c) datum feature identification

(d) datum feature controls

(e) datum feature order of precedence

(f) establishing datums from datum features

(1) datum features not subject to size variations

(2) datum features subject to size variations

(3) multiple datum features

(4) pattern of features

(5) screw threads, gears, and splines

(6) partial surface as datum features

(7) mathematically defined surface

(8) multiple datum reference frames

(9) simultaneous versus separate requirements

(10) simultaneous requirements and composite

feature control

(g) datum targets

(1) purpose/applications

(2) datum target symbol

(3) datum target points

(4) datum target lines

(5) datum target areas

(6) datum target dimensions

(7) datum planes established by datum targets

(8) methods of establishing a primary datum axis

(9) equalizing datums

(10) datums established from complex or irregular

surfaces

Rating Distribution

• 1 stars: 0 votes
• 2 stars: 0 votes
• 3 stars: 0 votes
• 4 stars: 0 votes
• 5 stars: 0 votes

Frequently Asked Questions

How long do I have access to the course materials?

You can view and review the lecture materials indefinitely, like an on-demand channel.

Can I take my courses with me wherever I go?

Definitely! If you have an internet connection, courses on Udemy are available on any device at any time. If you don’t have an internet connection, some instructors also let their students download course lectures. That’s up to the instructor though, so make sure you get on their good side!