Surface analysis and non-contact 3D measurement of tank track castings

Need

Under flat lighting the dull, rough texture of the as-cast surface produces dark specks that look like pores, and shadows from the lugs hide small cavities. The pin axis is a 3D quantity derived from the cylindrical surface of the lugs; it does not appear directly in a 2D image taken from above.

Solution approach

Two sensors share one head. The area camera images two fields under a grazing low-angle bar light: the light turns depth into shadow, so a pore stays dark inside with a bright rim facing the light and stands out from the shallow casting texture. The laser profiler then travels along the part to build the point cloud; cylinders are fitted to the pin lugs and the axis-to-axis distance is computed.

Process steps

1. 01

   Position

   The linear axis brings the measuring head over the casting on the table.

2. 02

   Surface

   Images taken under low-angle light are searched for pores, which are then sized.

3. 03

   3D scan

   The laser line travels along the part and builds a point cloud of the surface.

4. 04

   Measure

   Cylinders are fitted to the pin lugs and the distance between the pin axes is measured.

5. 05

   Decide

   Surface findings and the dimension are compared with the acceptance limits.