Analysis and developement of a semi-automatic assembly machine

Nowadays the assembly machines are widely used in the industries, since they reduce the production time and human error, while increase the accuracy and repeatability. The objective of this thesis is the analysis and development of the last part of a semi-automatic assembly line, that assembles and then tests two different camshaft phaser (intake and exhaust) for automotive applications. The line was completely designed and built by OTS Assembly, which is a company that deals, precisely, with the construction of prototypes of assembly machines. The main purpose is to program, and subsequently control, all the devices present in the unit, such as robots, drives, measurement instruments, sensors, actuators and so on, so that it is possible to create operating cycles of the stations that have to process the pieces. All these devices are managed by a fail-safe PLC Siemens 1500F (CPU 1517F-3 PN/DP), that is a fail safe controller that implements machine safety addition to managing the normal operations of the machine itself. The PLC is programmed with Siemens TIA Portal v15. In the last unit the products must undergo different processes and three tests are performed: a runout measurement on the intake cam phaser to calculate the radial runout of a specific feature, an end-of-line test, on both products, aiming at determining if there are defective pieces or specications are not matched by simulating critical working situations, and, in the end, a leak test, always on both products, to detect manufacturing defects that correspond to a leakage of gas from the product. Another purpose is to create a direct interface with the operator that is going to use the machine. Thus, a Visual Basic implementation has been created to show, for example, warning messages or alarms present inside the machine, so that, even if the operator does not know anything about programming, can understand what is happening. Moreover, thanks to this implementation it is possible to read appropriate memory areas of the PLC, where are stored the informations that have to be showed to the outside, but it is also possible to write in other memory areas. This is very usefull to set determinate parameters, such as pressure parameters for the tests, the velocity of the motors and so on, avoiding the operator having to go and write them directly programming the PLC.