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A method for solving the problem of bend sequencing in sheet metal manufacturing is presented. The algorithm developed divides the part into basic shapes (channels and spirals) and determines the partial sequences associated with them. The complete bending sequences associated with the complete part were obtained from the combination of these partial sequences. To make this combination possible, several strategies were defined to reduce the number of solutions and, therefore, the searching time. All sequences (partial and complete) were checked considering possible part-tool collisions and tolerance constraints. The last stage was to order the sequences by taking into account the total process time. To attain the required process time accuracy, a robot was used for the handling operations. Finally, the sequence associated with the lower process time was selected as the optimal solution.

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a b s t r a c tConoscopic holography (CH) is a non-contact interferometric technique used in surface digitizing. Like other laser techniques it is influenced by different factors such as surface reflectance, material, colour or even speckle noise caused by roughness. In this work, a CH system was used for analysing the influence of roughness on surface digitizing. For this purpose, several digitizing tests were performed on roughness specimens corresponding to EDM, face milling and flat grinding processes. Each roughness grade was digitized under different combinations of the sensor setting parameters (frequency F and power P) which satisfy that the signal acquired by the sensor lies within the quality values recommended by the manufacturer. The results were analysed by using two indicators that show quality of the points captured by the sensor regarding the surface geometrical reconstruction and its metrological reliability. Finally, the study provides a series of recommendations for adjusting the sensor in order to satisfy both indicators simultaneously.

The current requirements for an efficient dimensional inspection of manufactured parts have lead to development of different in process and on-machine measurement (OMM) techniques. Touch trigger probes (TTP) are the most common technologies utilized, inspired on contact probes used on coordinate measuring machines (CMMs). The on-machine accuracy of TTPs depends upon precision of the tool-machine control as well as upon the procedure for TTP presetting. Taking this into account, a different OMM technique is considered in this work, which consists on a laser micrometer (LM) that is commonly used for in-process measurement of continuous products. The behaviour of TTP and LM is analysed and discussed in terms of repeatability and reproducibility. Results obtained by both techniques are compared each other by measuring a cylindrical workpiece and by checking the results with those obtained on a CMM.