Tecnologie di giunzione di materiali polimerici

Aim of this work is to carry on joining of thermoplastic components in order to extend its results, in the future, to semi-manufactured components obtained through injection moulding processes. Although this technology has remarkable advantage as productivity, automation and cheapness, doesn’t allow to produce hollow components all at once. For this reason it is necessary to add a successive joining process. The most common technologies now used to join plastic materials shows that the Hot Plate Welding process is characterized by advantages as mechanical strength, freedom in design, cheapness, etc. On the other hand Laser Welding shows remarkable advantage as process speed, aesthetic quality, mechanical strength, versatility, minimum and local transfer of energy and absence of contact. Through Hot Plate welding the author carried out samples welded in different configurations changing process parameters like temperature and time of interaction. The characterization of the joining has been done through tensile test, in comparison with an one-piece sample. Results confirm Hot Plate is a valid technology although further development are necessary to optimize the process. Concerning Laser Welding the author chose a Diode Laser because of his efficiency, cheapness, lightness, smallness and lower specific power than the other lasers. Preliminary tests, performed to analyze interaction laser-material, allowed to determine optimal process parameters. Samples have been welded with various configuration and mechanical properties has been determined for each one. Laser joining could be carried out changing fundamental parameters like pressure, speed, temperature, focalization of the beam and power. Results show how some parameters have a great influence on joining. In order to further develop this technology and to estimate the advantages of other processes, it is necessary to define quantitatively these parameters in order to outline a control process.