Sistemi flessibili per l'assemblaggio industriale

Manufacturing companies currently have a tendency to expand more and more their production mix, on the one hand to satisfy fully the requirements of the market, which are becoming increasingly pretentious, on the other hand to diversify production, in order to disengage from any failure that a single product can found. So it will be offered different products of the same family and each product will have some variants that permit to customize it. It is clear that this way of working can become problematic, particularly if factories intend to automate the different stages of the production cycle. There are no doubts about the fact that among all the operations that lead to obtain a finished product, the assembly operation is the most critical, in particular because assembly is affected by all errors due to the operations carried upstream. Then, it is possible to say that to automate the assembly operations of a customizable product is considerably complex and the traditional ways to design an automated system may be inadequate. The necessity of flexibility in automatic assembly is a topic widely discussed in the context of the industrial engineering, however, studies conducted by the research, in order to propose a rational method for the design of an automatic flexible system, are quite modest. The research activity presented here proposes a new class of flexible assembly systems: the robotized work cell F-FAS (Fully - Flexible Assembly System). The modeling of this automatic system, based and validated by experimental tests, has allowed to compare the potential of this machine with those of traditional systems for flexible assembly, allowing to state that this work cell is very competitive, in particular for conditions of extremely varied productive mix. The modeling cited above also allows to proportion properly the robot work cell, in according with the necessities of production. During the study of F-FAS prototype, some interesting aspects of the subsystems that compose the work cell are surfaced, in particular, it was found that the characteristics of the end-effector for the robot heavily influence the performance of the machine. That is why it was decided to dedicate an important part of the research activity at the design of this subsystem and at its subsequent building with rapid prototyping technology.

L’attività di ricerca presentata in questa tesi di dottorato propone una nuova classe di sistemi flessibili di assemblaggio: la cella robotizzata F-FAS (Fully -Flexible Assembly System). La modellazione di questo sistema automatico, basata e convalidata da prove sperimentali, ha permesso di confrontare le potenzialità di questa macchina con quelle dei sistemi tradizionali di assemblaggio flessibile, consentendo di affermare che tale impianto risulta assai competitivo, in particolare per condizioni di mix produttivo estremamente vario. La modellazione citata inoltre permette di proporzionare adeguatamente la cella di lavoro sulla base delle esigenze di produzione. Durante lo studio condotto sul prototipo di cella F-FAS, sono affiorati alcuni aspetti interessanti relativi ai sottosistemi che la compongono, in particolare è emerso che le caratteristiche dell’end-effector per il robot risultano influenzare pesantemente le prestazioni dell’intera macchina. Ecco perché si è deciso di dedicare una parte importante dell’attività di ricerca alla progettazione di questo sottosistema e alla sua successiva realizzazione, mediante tecniche di prototipazione rapida.