The American Society of Mechanical Engineers, or ASME, authors the ASME Y14.5 Dimensioning and Tolerancing standard. This standard establishes the rules that must be followed when utilizing Geometric Dimensioning and Tolerancing (GD&T). It also outlines all fourteen GD&T symbols and other important rules required for creating standardized engineering drawings.
The ASME Y14.5 is one of the most important standards in all mechanical engineering and undergoes a revision every 10-15 years or so. The most recent years of revision are 1994, 2009, and 2018. A company can operate under any revision of the standard, but they must adhere to the rules as outlined in that revision year. At the time of this writing, ASME only offers certification for the 1994 standard and the 2009 standard.
For each revision year of the standard, there are two levels of certification an individual can receive: Technologist-level Certification and Senior-level Certification. In our experience working with thousands of companies, the ASME Y14.5 2009 edition is currently (as of 2023) the most widely used and accepted version of this standard.
At GD&T Basics, our trainers are all Senior-level Certified – though a few of us have experience taking both exams. In this article, we will highlight the differences between the 2009 GDTP Technologist and 2009 GDTP Senior level exams, explain the benefits of each, and help you understand what is necessary to begin preparing for either of these exams.
ASME Examination for GDTP 2009 Technologist Certification (4hrs 150 questions)
The ASME Exam for Technologist-level certification has no work experience prerequisite, and registration is open to everyone. Technologist-level exam registration information can be found on the ASME website.
The Technologist level exam is 4-hours long and made up of 150 questions. You are allowed to bring scratch paper and a non-programmable calculator. Questions are broken down into 9 categories, shown below. In order to pass and receive your certification, you must obtain at least a 50% in each category and a 78% overall.
- Scope – 10%
- General Dimensioning – 10%
- Symbology – 5%
- Datums – 20%
- Form – 5%
- Orientation – 5%
- Location – 25%
- Profile – 15%
- Runout – 5%
This exam aims to certify individuals who are interpreting drawings for manufacturing, sales, or quality departments. It includes more description-based questions to ensure that you understand the basic concepts of GD&T, as well as how to read and interpret a drawing that utilizes these concepts. There is some math involved, and it is centered around calculating the virtual condition of various features, as well as calculating tolerance values when modifiers are applied. An example would be: “What amount of total positional tolerance is applied to a part when the feature’s size is given, and the Maximum Material Modifier is applied to the feature control frame?”
This exam will not verify that you know how to apply GD&T to a drawing or make critical design decisions when drafting or modeling a part for production. What it does do is cover all of the topics across the standard and verify that you have a fundamental understanding of GD&T so that you are able to interpret a drawing correctly. It certifies that the interpreter can apply technical knowledge to the symbols and features on a drawing and begin analyzing the real-world part to the rules outlined on that drawing. Concepts like composite position, composite profile, simultaneous requirements, Maximum and Least Material Boundaries, and many more are covered in this test. Questions will be formatted to ensure the test taker holds a basic understanding of GD&T.
Not every symbol and concept in the standard can be covered in this test. Still, anyone looking to take this test must prepare themselves so that they have a fundamental understanding of each of the 9 categories listed above.
ASME Examination for GDTP 2009 Senior Certification (6hrs 150 questions)
The ASME Exam for Senior-level certification requires verification of 5 years of experience working with GD&T. Senior-level exam registration can be found on the ASME website.
The Senior-level exam is 6-hours long and includes 150 questions. Similar to the Technologist-level exam, you are allowed scratch paper and a non-programmable calculator. Questions for the Senior-level exam can be broken down into 7 categories, shown below. To pass and receive your certification, you must obtain at least a 50% in each category and a 78% overall.
- Scope, General Dimensioning, Symbology – 10%
- Datum Referencing – 30%
- Form – 5%
- Orientation – 5%
- Location – 25%
- Profile – 20%
- Runout – 5%
This exam aims to certify individuals who plan to apply GD&T in their role. A Senior-level certification intends to prove that the individual knows enough about GD&T to select and apply all the rules and symbols outlined in the standard to control the features of a manufactured part appropriately. There are multi-step calculations that must be done in some questions that relate internal and external boundaries between features and the design intent behind them. A deep level of understanding of datum structures and their effects on other features is also crucial. Other questions will focus on your knowledge of how to control Size, Location, Orientation, or Form using the 14 GD&T symbols alongside different datum reference frames. Additionally, the fixed and floating fasteners equations for calculating position tolerance are also on this exam. (Information on these equations is found in the Nonmandatory Appendix B of the standard- “Formulas for Positional Tolerancing.”)
Questions and Answers from our Certified Trainers
Which exam is harder, and why?
The Senior-level exam is more difficult because it requires an understanding of the content within the standard which allows an individual to make design-level decisions about features on a part. Questions are centered around conceptual topics that ensure the test taker can not only interpret a drawing but also understand why it’s interpreted that way – and why it’s essential. Design-related calculations are also more in-depth and include multiple boundaries.
The Technologist-level exam is easier because it focuses on the basic concepts of GD&T and avoids the “why” and “how” of GD&T. It does, however, cover all the same general topics as the Senior-level exam – and perhaps even more if we consider the print reading and general dimensioning questions.
Which certification would you recommend?
For the vast majority of our students, we recommend taking the Technologist-level exam. If you are using GD&T regularly – whether you’re a machinist reading drawings, a drafter creating drawings, or an inspector interpreting drawings – we have found that the Technologist-level certification is more than sufficient. This exam, in our opinion, certifies the required level of knowledge to complete the majority of the tasks associated with most of the industry. Similar to our courses, it focuses on the real-world technical aspects of GD&T that are used and applied 90% of the time.
For the vast majority of our students, we recommend taking the Technologist-level exam.
However, if you are in a position where you have to review/sign off on crucial design decisions for geometric tolerances on a part, are considered an industry expert, or are a companywide expert, we recommend taking the Senior level exam. Our trainers at GD&T Basics are all Senior Level Certified because we assist and advise clients across numerous industry sectors. Because of these broad requirements, is best to know every aspect of the ASME Y14.5 standard.
We also suggest if you are confident in your skills and believe you will “someday” wish to be Senior-level certified, that you bypass the Technologist exam and head straight to the Senior-level exam.
What courses do you have to help prepare me for the exams?
To best prepare for the Technologist exam:
We recommend utilizing our Expert bundle which includes 3 courses: Print Reading and Tolerances, GD&T Fundamentals, and Advanced GD&T. The Technologist-level certification will contain questions from all of the topics covered in these courses. Much like the Technologist exam, our course curriculum focuses on the concepts that you need to know to implement GD&T in real-world applications. Additionally, all of our courses include access to live and pre-recorded webinars where we expand on various GD&T topics covered in the exams.
We also recommend that anyone planning to take the Technologist-level exam purchase and read the ASME Y14.5 standard cover to cover.
To best prepare for the Senior-level exam:
For the Senior-level certification, we again recommend utilizing our Expert bundle and reading the ASME Y14.5 standard from beginning to end. However, as we mentioned, the Senior-level exam goes above and beyond the Technologist exam and requires a deeper understanding of GD&T. This is why they require a minimum of 5 years of experience using GD&T before taking the exam. For this reason, real world use of GD&T and a deep study of the standard are definitely required for Senior-level certification in addition to the courses we offer.
Tactics for test taking and studying:
Regardless of which exam you plan to take, here are a few pointers on preparing for and taking the exam.
- Take a practice test to become self-aware of your knowledge of the topics.
- Write down the formulas for the virtual and resultant condition of internal and external features of size when they are modified with both LMC and MMC. These calculations will be done frequently throughout the exam, especially during the Senior-level exam. (You can see the video below)
- Read the ASME Y14.5 standard cover-to-cover. There are MANY lesser-known symbols and rules that may be referenced on the test. Some sections of the test are made up of only a few questions, and you must score at least 50% in each section to pass – so making a thorough read-through of the material is a must. (The ASME Y14.5 standard can be purchased from the ASME website.)
- Take a training course or two. Whether it’s one of our courses or another’s, training courses will help you gauge where you are at in understanding the complex topic of GD&T. Sometimes, you don’t know what you don’t know. (We recommend taking our Expert bundle of courses.)
- When taking the exam, answer the questions you know, and mark the ones you can’t answer as you go along. At the end of the exam, you are allowed to revisit any marked questions. You should have plenty of time to complete the exam.
Whether you are looking to become Technologist or Senior-level GDTP certified, we hope this information has helped you gain a better understanding of the exams and how to prepare for them.
GD&T Basics would love to come alongside you in your journey to GDTP certification! For more information on our GD&T training, check out our course options.
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