The Research And Implementation Of The Control System Of A Small FDM 3D Printer

3D printing is an emerging manufacturing technology. Because of less raw material waste and higher complexity in manufacturing,3D printing is widely used in fields like mechanics, construction, and biomedicine. Market demand of light weight and low cost 3D printers is expanding as 3D printing technology entering civilian areas. This paper develops a control system of a small FDM 3D printer based on ARM and Android.Firstly, the control system architecture, PC+Android+MCU, is proposed after function requirements analysis. The system can be divided into 4 parts, i.e., temperature controlling, motor controlling, man-machine interacting, and data reading. A task scheduling method combining time slice polling and timer driving is also put forward.Then, software realization of the system is discussed. (a) Accurate control of temperature of the nozzle is achieved based on the PID algorithm. (b) The speed of motor is optimized, and the motion of multi-dimensional stepper motors is realized using Bresenham algorithm. (c) An object oriented method of the multistage menu design and the procedure of key reading are developed in LCD&KEY based man-machine interaction. For the Android based man-machine interaction, two parts, i.e., local part and remote part, are considered. The communication protocol between MCU and the local part and that between the local part and the remote part are designed and realized. (d) The data reading module consists of two parts, U disk and SD card. The development of SD cards is based on SDIO, and a file system is transplanted to manage the data. In addition, a U disk reading module is developed using the USB bus interface chip CH376.Finally, the test of motors shows that the system can achieve accurate linear motion. Furthermore, print test shows that a printer with the developed control system can print 3D model successfully and accurately. The printed model has good smoothness, and the details of the model are also printed precisely.In this paper, based on the realization of 3D printing, Android is introduced to the 3D printing technology for the first time to meet the market demand for low cost 3D printers.