Adhesives in CAD

A new ASTM International standard is providing engineers with a convenient method for representing adhesives on a computer-aided design (CAD) drawing.

The standard was developed as a result of a collaborative effort between ASTM and the Adhesive and Sealant Council.

Lawrence Sloan, president of the Adhesive and Sealant Council (ASC), said that the symbol described in the new ASTM D7447 standard, which defines the method for symbolising adhesives, originated with a focus group that ASC conducted with engineers, designers and architects to learn about their perceptions of adhesives.

The focus group results indicated that those questioned would be more apt to specify adhesives if they could be represented conveniently on a CAD drawing, rather than the current method of embedding comments in a 'notes' section.

Designers, engineers, architects and anyone else preparing a CAD drawing would benefit from use of ASTM D7447, according to Sloan.

ASC based the methodology of the symbol on the American National Standards Institute/American Welding Society A2.3 standard, Symbols for Welding and Nondestructive Testing, and the International Organization for Standardization (ISO) 15785 standard, Technical Drawings - Symbolic Presentation and Indication of Adhesive, Fold and Pressed Joints.

'ASC approached ASTM in 2006 with the idea of creating a new standard in tandem with the symbol, as it was felt that standardisation would help build international credibility within the design-engineering community,' said Sloan.

'Plus, we received grassroots interest from Mercedes and other automotive companies in Germany, supporting our decision to work with ASTM International.'

ASC has also developed an electronic file based on ASTM D7447 that consists of a series of fields that the designer can populate with information such as adhesive chemistry type and physical form, surface preparation and curing information.

'The electronic file is a convenient way for the designer to represent an adhesive’s many characteristics in one symbol by eliminating the tedious task of manually adding adhesives in the notes section of a CAD program,' added Sloan.