Spray-hole position and angle check on the injector nozzle

Need

Hole openings on the bright, curved nozzle tip appear elliptical, and reflections can hide their edges. A top view gives the position of a hole but not its direction: axis inclination only shows when looking along the hole, so every hole has to be brought onto a camera axis one at a time.

Solution approach

A telecentric top camera measures the hole centres under ring light without perspective error; position and angular spacing are checked against the pitch circle. An oblique camera sits on the nominal hole axis and a rotary nest indexes the nozzle. If hole mouth and hole bottom look concentric, the axis is correct; their offset gives the inclination. Cameras and nest axis share one calibration.

Process steps

1. 01

   Position

   The slide brings the next nozzle under the top camera.

2. 02

   Top acquisition

   The ring light strobes and the telecentric camera images the hole openings on the dome from above.

3. 03

   Hole spacing

   Hole centres are located in the top view; their positions and angular spacing are compared with the nominal places on the pitch circle.

4. 04

   Axis inclination

   The rotary nest brings each hole in turn onto the axis of the oblique camera; the axis angle is measured by looking along the hole.

5. 05

   Decide

   Position, angular spacing and axis inclination are evaluated together; the deviating hole is highlighted.