Part Three Laser Scanning

Frrrther validation of the model was obtained by comparison with the weld line widths from joining trials conducted tmder the modeled process conditions. Two plaques of dimensions 83 mm x 27 mm x 3.2 mm were scanned, with laser focused on the upper surface of the transparent part. Three parallel weld lines were made. From 8 to 11 width measurements were made along each line. Average widths ranged from 0.89 to 0.99 mm, with overall average of 0.95 irun and standard deviation of 0.13 mm. It is possible that the greater experimental weld line width is due to insufficient joint pressure (weld pressure was estimated to be 0.7 MPa). Higher pressure will improve conduction from absorbent to transparent part and thus likely will reduce the temperature rise and consequently the weld line width. 

Different concepts of vision systems exist in the industiy. They either use image analysis or visual feedback to locate the part. The part position information is passed to the scan head control system to align the laser maik to the part. Three of the common approaches are ... 

Trace (a) of Fig. 28 represents part of the pure rotational laser Raman spectrum of 02. This example is a single scan of the S3 transition J = 3 to J — 5 in the ground state. This transition is split into three components... 

Figure 9.19 Scale analysis of North Sea houting from Ijsselmeer lA-ICP-MS, a) photograph of a scale, b) part of a scale with laser craters obtained by LA-ICP-MS measurement in line scan modus, c) Sr Ca ratio for nine North Sea houting caught in Ijsselmeer in 2001/2002. The results were sorted into three different types A Fish that only lived in freshwater B Fish that lived for a fairly long period in fresh water, then moved to sea water and returned to fresh water where they were caught C Fish that obviously moved quickly to sea water after hatching (period from hatching in fresh water until the arrival in the sea was to short to measure a ratio that normally indicates fresh water) and returned to...

Figure 10 shows a typical setup of a two-photon photopolymerization CAD-CAM system. It consists of three parts, fvdfilling functions of (i) CAD and scanning control, (ii) laser output and beam control, (iii) two-photon exposure and in-situ monitoring. 

---