Fresadora CNC microcontroladora para confecção de placas de circuito impresso

Abstract

During the course of Industrial Mechatronics a recurring difficulty was observed when fabrication of Printed Circuit Boards, known as PCBs, was required from the students. Existing manual processes don’t provide an adequate final result and usually present great instability due to both the lack of students’ practice and robustness of those processes themselves. Additionally, automated processes are expensive for production or commercialization in small-scale, such as for a single board for prototypes. Companies capable of such processes tend to refuse those clients, because, since they are capable of large scale production, small batches represent a loss in productivity and profit. Therefore, an opportunity was detected to serve this market with an equipment that is simple to be built and easy to be used, enabling the production of PCB prototypes quickly and economically. To achieve that, it was chosen an uncomplicated to build Computerized Numerical Control (CNC) milling machine, utilizing commercial aluminum profiles and as many easily fabricated parts as possible. The chosen model is based on the moving table system, in which the table moves on the X axis while the other two axes are installed in an unmoving structure. Tool rotation is achieved through a Dremel-type rotary tool. The employed solutions based on Open Source technology and well known systems are explained. The electronics focus on the interpretation of GCODE, generated by PCB creation softwares, on the Arduino Mega. The Marlin firmware, also Open Source, configured to play reasonably as a milling machine is applied. Machine control, therefore, is done through a computer connected directly with the Arduino board via Universal Serial Bus (USB). Achieved results were a CNC milling machine built within the budgetary limits desired, capable of machining an area of 220 mm x 140 mm with acceptable quality for circuit board production.