How to balloon a mechanical drawing for AS9102

The process engineer has to prepare the first article inspection (FAI) package for a complex machined part with more than 150 requirements. They need to balloon the mechanical drawing without missing a single dimension or creating duplicate numbers. One ballooning mistake breaks the match with AS9102 Form 3.

Rules and method for ballooning a mechanical drawing

This practical guide covers ballooning a drawing without omissions, the balloon numbering rules and preparing the FAI package.

Type of characteristic	How the balloon is placed	Example balloon number
Linear dimension	Numbered balloon with a leader to the dimension	Balloon 12
GD&T feature control frame	Balloon pointing straight at the frame	Balloon 45
Title block note	Balloon around the note at the bottom of the drawing	Balloon 101

Numbering the balloons in a logical order

Balloon the drawing clockwise, starting from the title block at the bottom right, then sweep the drawing zone by zone (A1, A2, B1…). To keep the match with the inspection reports, read our article on filling in AS9102 Form 3.

Multiple and repeated characteristics

For a note such as ‘4x ⌀8 H7’, give one main balloon (e.g. Balloon 22) and break it down into lines (22.1, 22.2, 22.3, 22.4) in the inspection report, to record the four individual readings.

Full example: ballooning a transmission housing

A housing carries 85 dimensions, 12 geometric tolerances and 3 title block notes. The drawing is ballooned in full, from 1 to 100. Verdict: the balloon list is approved and can be exported straight into the FAI grid.

Common pitfalls when ballooning drawings

The first pitfall is forgetting the title block notes (e.g. break sharp edges). The second is balloons hiding the figures on the drawing. The third comes from a revision change without renumbering. To balloon your PDF drawings automatically in one click, use drawing ballooning software such as CoteCote and its automatic dimension detection.