SMT007 Magazine

SMT-Aug2014

Issue link: https://iconnect007.uberflip.com/i/357479

Contents of this Issue

Navigation

Page 47 of 76

48 SMT Magazine • August 2014 INtRODuCtION tO INLINE aXI tEChNOLOgy continues aRTIClE tillating materials that emit light when struck by ionizing radiation, it has become much eas- ier to obtain instant high-resolution digital X- ray images using specialized CCD cameras that remove the need for additional photo-chemical processing. The single obvious limitation of X-ray im- ages is the inability to distinguish the spatial structure of overlapping objects. This short- coming has been initially addressed by chang- ing the orientation of the target object, but this requirement placed additional stress on the op- erator and may be completely impossible for large objects. Fortunately, modern computers have al- lowed us to overcome this limitation by cal- culating 3D cross-sections of the target objects from a series of 2D X-ray images captured from different angles. In the next section, we will de- scribe the three distinct 3D technologies that have found practical applications in industrial PCB production. technical X-ray applications 2D X-ray Modern industrial applications depend on digital X-ray imaging, using an X-ray camera to capture images. A typical example is manual X- ray Inspection (MXI), which allows the opera- tor to manipulate the inspected object to look for defects from different angles. 2D AXI An evolution of manual 2D X-ray is auto- mated X-ray inspection (AXI), which uses cus- tomizable inspection programs to scan and re- view transmission X-ray images to find parts that do not conform to preset manufacturing parameters. This reduces operator workload and allows for much higher inspection speed with a lower number of false calls. Despite its advantages, 2D AXI is still limited by overlap- Figure 2: in a typical microfocus X-ray source tube, the cathode filament is heated up by passing current to emit electrons, which are then accelerated towards the tungsten target and focused by electromagnetic focusing grids. The impacting electrons then cause the Tungsten atoms in the target to emit X-rays. Figure 3: 2D X-ray offers very high resolution and speed, but cannot separate overlapping components on dual sided PCbs.

Articles in this issue

Archives of this issue

view archives of SMT007 Magazine - SMT-Aug2014