A guide for enhancing quality in engineering drawings : preparation and requirements

The quality of designed products is limited by the number of mistakes and errors in drawings. But, drawings can be very complex, especially those of large machines consisting of many parts and mechanisms. To check such drawings for accuracy and clarity, and be able to deliver error free drawings can be a daunting task. Procedures in most drawings manuals such as the NASA (1994) and ISO 128-1 and standard drawing textbooks, besides assuming that drawings are of a kind, do not give a total approach to the enhancement of quality in engineering drawings. From 1997 to 2000, this author, working as design engineer recorded comments, for purposes of personal work improvement, made by his supervisor on drawings sent to him for approval. From 2005 to 2010, the author observed and recorded checking notes and comments made by other design engineers. These notes and comments were analysed and compared to procedures prescribed in drawing manuals and textbooks. It was established that the notes, manuals and textbook procedures could be categorised into three main classes: 1) general information; 2) shape, size and material description; and 3) clarity requirements. Moreover, further review of the extant drawings literature established that the literature fails to appreciate that different checking methods apply to different drawing scenario. Consequently, two distinct drawings scenario; Drawings-for-Prototyping and Drawings-for-Documentation, are presented. Lastly, it is observed that the introduction of computer controlled production equipment brings with it changes in drawings checking procedure and style, what in this paper is referred to as: technology induced drawing style.