MINIMIZING ERRORS IN PCB MILLING PROCESSES THROUGH A 3-AXIS PCB ROUTER

Abstract

Printed circuit boards (PCBs) can be produced by chemical or mechanical methods. Continuous copper paths are difficult to print in the chemical method and breaks may occur in copper paths. In addition, this method is harmful to human health and the environment, as various chemicals are used. In the mechanical method, PCB is processed with computer-controlled numerical workbenches (CNC). Although prototyping can be done quickly and without harming the environment with these benches, the desired results may not be obtained. Reasons for unsuccessful machining in CNC machines; manufacturing and assembly errors in the production of benches, the use of low quality mechanical and electronic components, and the reference of a single point especially for the Z-axis of the part connected to the benches. In this paper, a precise and stable PCB Router is presented to make fast, cost-effective and successful PCB machining. In order to minimize the vibration and oscillations of the PCB Router caused by manufacturing and assembly errors, the dimensions of the router were kept low and metal material was preferred for the router body. Precision is ensured by quality motor drivers and stepper motors. The PCB Router is controlled by an original control board. This card is equipped with a multi-point referencing feature for the Z-axis. Thus, homogeneous machining in the Z-axis for the entire surface of the PCB can be realized by performing referencing operations on the PCB connected to the workbench as many points as the user enters. With the developed router, PCBs with rectangular and circular patterns were engraved at cutting depths of 0.030 mm and 0.050 mm with 0.20 mm and 0.30 mm diameter milling tools with a 30-degree tip angle, respectively. Moreover, a 16-terminal integrated circuit element was successfully engraved at a cutting depth of 0.040 mm with a 0.34 mm diameter V-tip with a 30-degree tip angle. Homogeneous milling was achieved utilizing the proposed multi-point referencing feature. Each milling operation was completed in approximately 30 min - 45 min.