New ASME Standard for CAD

The American Society of Mechanical Engineers (ASME) has unveiled a new technical standard, AMSE Y14.41-2003, which establishes requirements for preparing, organizing and interpreting 3-D digital product images. The standard also provides a guide for CAD software developers working on improved modeling and annotation practices for the engineering community. ASME Y14.41 sets forth the requirements for tolerances, dimensional data and other annotations.

“This standard is unique because it covers the same information in both the 2-D and the 3-D world,” says Alex Krulikowski, chairman of Y14.41 at ASME and engineering process leader of dimensional engineering at General Motors. “The same set of standards are applicable to both 2-D and 3-D modeling.”

ASME Y14.41 advances the capabilities of Y14.5, Dimensioning and Tolerancing, the widely used standard pertaining to 2-D engineering drawings. Y14.41 defines the exceptions as well as additional requirements to existing ASME standards for using product definition data or drawings in 3-D digital format.

According to Krulikowski, prior to ASME Y14.41, nothing in the industry dealt with the display of tolerance information on 3-D models. “For years, we had the ASME Y14.5 standard that we used on drawings. People were trying to use that standard and tie it to modeling and it didn’t work well. This standard, the new AMSE Y14.41, tells an engineer how to do that. The Y14.41 standard itself is a standard that deals with the display of tolerance information on 3-D models.”

Without the new standard, according to Krulikowski, it would be impossible to translate tolerance information without a common understanding of it.

“For a number of years now, the industry has been developing the technology to create 3-D models,” says Krulikowski. “What has been overlooked is how you transfer the tolerance information along with a 3-D model. They have been successful in being able to take a model and go to a machine shop and machine the part right off the model. But to know if the part is any good or not you have to understand its allowable variation. We haven’t been successful in putting that in the model. And that is where the ASME Y14.41 standard is a major step. It now provides us with a way to communicate that information along with the model in a standard way.”

While ASME is a North American organization, its standards are becoming quite global. “Standards have a different role than they did years ago,” says Krulikowski.

“We used to have standards in each country, but now with companies being global, if a major corporation adopts a standard, they’ve got plants all over the world so the standard gets used all over the world.

“With most companies today,” continues Krulikowski, “when they adopt an ASME standard, it becomes a global standard, rather than a national standard. This can sometimes create a challenge in developing new standards. There is a lot of work that needs to be done to harmonize these things. Currently, there still are standards developed and published in other countries, making it difficult because a company might have to work with two or three standards. The quicker we get to one standard, the better it will be for the industry.”

Another benefit to Y14.41, says Krulikowski, is that this standard is an enabler for manufacturers to implement a math-based process. “Everyone is trying to get to math base. This is one of the key pieces that is missing for manufacturers. The ASME Y14.41 standard is also an enabler to eliminate paper drawings and it provides software manufacturers a common set of rules to develop math-based tools around.”

Representatives from several industries were involved in developing the new ASME Y14.41 standard, including automotive, aircraft, heavy equipment and CAD software manufacturers.

According to Krulikowski, the new ASME Y14.41 standard targets anyone who manufactures parts and uses a CAD system.