Quality inspection on internal structures of pencils using X-Ray micro-computed tomography

  • P Listiaji Universitas Gadjah Mada, Indonesia
  • R H Fitra Universitas Gadjah Mada, Indonesia
  • B E Prabowo Universitas Gadjah Mada, Indonesia
  • G B Suparta Universitas Gadjah Mada, Indonesia


The inspection on internal structures of pencils has been done using X-ray micro-computed tomography (μ-CT) developed at the Department of Physics, Gadjah Mada University. Three types of pencils, i.e., a hexagonal cross-sectional shape 2 B pencil, a triangular cross-sectional shape HB pencil, and broken pencils on the inside were scanned. Furthermore, the images of tomography reconstruction results were compared with the internal physical structure of the pencil. The results showed that the materials of wood, air, and graphite could be distinguished based on the cross-sectional images. They can be seen from the difference in gray level values that associated with linear attenuation coefficients. Graphite on HB and 2B pencils shows different gray levels. The internal segments of the wood were also shown clearly. Also, the fractures that occur in the internal of the pencil can be well identified.