Gap and Flush

Gap and flush are the two key measures of how vehicle body panels fit together: gap is the distance between adjacent panels, and flush is the height difference between their surfaces across the gap.

Gap is measured across the joint between two panels, such as a door and a fender, and flush is the step between the two outer surfaces. Both are checked at defined points around closures, lamps and trim. Measurement has moved from feeler gauges and mechanical tools to handheld laser and optical gauges and to inline stations, where fixed or robot-mounted sensors measure many points on every body.

Consistent, tight gaps and flush surfaces are a visible sign of build quality and also affect wind noise, water sealing and door closing effort. Gap and flush data are collected in the body shop after closures are fitted and again in final assembly after trim and lamps are added.

Results depend on stamping accuracy, body-in-white geometry, hinge and closure setting, paint and the fitting of trim parts, so data are used with statistical process control to find the source of variation. Specifications are set by each vehicle manufacturer for each joint. Measurement systems must be calibrated and checked for repeatability before their data are used for decisions.

Key points

Gap is the distance between panels; flush is the step between surfaces
Affects perceived quality, wind noise, sealing and door effort
Measured by handheld laser gauges and inline sensor stations
Variation comes from stamping, body geometry, hinges and trim

Where AiVibe comes in

AiAmbA use cases include visual inspection on textile and automotive lines, predictive maintenance and digital twins. Existing lines are retrofitted with edge devices, and AI agents only propose changes for a trained operator to confirm.

Explore AiVibe’s work in Textile & Automotive Manufacturing →

Related terms

Terms that refer to Gap and Flush

Resistance Spot Welding (RSW)Textile & Automotive Manufacturing