Mechanical Design

Engineers can perform a tolerance analysis to determine how dimensional variations across mating parts combine within an assembly. Individual dimensions may each satisfy their specified limits while their combined variation produces insufficient clearance, excessive play, misalignment, or interference. Geometric dimensioning and tolerancing may also define allowable variation in form, orientation, location, and related geometric characteristics that affect assembly fit and function. ASME Y14.5 provides standardized rules for stating and interpreting these dimensional and geometric requirements.

A mechanical design can be verified through methods such as engineering calculations, analysis, inspection, demonstrations, prototype evaluation, and testing. The appropriate method depends on the requirement being evaluated, such as strength, movement, dimensional fit, temperature capability, or another performance characteristic. Verification compares the design or resulting product with defined requirements to determine whether those requirements have been satisfied.

Engineering change orders can help establish when a design concern was formally documented or when a change was proposed, reviewed, approved, or implemented. Revision histories, redlines, change requests, engineering change orders, and updated drawings may identify changes to dimensions, materials, interfaces, or other design requirements and may state why the change was made. These records should not be treated as proof of the first time anyone became aware of an issue unless the documentation specifically establishes that chronology.