To achieve high resolution, the distance between the workpiece and the X-ray tube must be very small. If it is large, flat workpieces such as printed circuit boards are to be tomographed, the large aspect ratio could lead to a collision between the workpiece and the X-ray source when it is rotated to acquire radiographic images. A solution is provided by Swing and Planar Laminography, where the angular range for capturing radiographic images is greatly reduced, or movement takes place only in a planar manner.

In Swing Laminography, the workpiece is rotated within a specific angular range, e.g., ±20 degrees. For Planar Laminography, the workpiece is moved through the X-ray beam while the detector and X-ray tube move in opposite directions. Due to the conical shape of X-rays, the angle of transmission changes during the process. This virtual rotation of the workpiece provides sufficient information to reconstruct the volume of the workpiece. The lateral resolution in different measuring planes is very high, defined by the selected magnification, while the axial resolution is lower, which is typically not problematic in 2D applications.

Advantages of Planar Laminography:

Improved resolution since there is no rotation, allowing the workpiece to be positioned closer to the tube.

For workpieces with a large aspect ratio, the entire workpiece is accessible, as measurements are not limited to the position of the rotary axis.

(In planar laminography, rotation of the workpiece is replaced by moving the X-ray tube, workpiece and detector in different directions)
(Comparison of swing and planar laminography based on the measurement of an printed circuit board)

Laminography is used, for example, in the analysis and measurement of printed circuit boards and electronic assemblies, the analysis of archaeological samples, 2D measurements of large metal sheets or flat plastic parts, and the measurement of bipolar plates.”