ABSTRACT With the advancement of technology, demand for Computer NumericalControl (CNC) plotter machines in Educational Institutions and Laboratories israpidly rising. Low cost manufacture of Printed Circuit Board (PCB) has becomea basic need in electronics laboratories, for electronics engineering studentsand for electronics hobbyists. This paper will present an affordable model of aCNC plotter machine which is able to draw a circuit layout on PCB or any othersolid surface using simple algorithm and available components.
At first theuser needs to convert any image file or text file into G code using Inkspacesoftware and then feed it to the machine using Processing software. Arduino unowith an ATmega328P microcontroller is used as the control device for thisproject. The microcontroller converts G-code into a set of machine languageinstruction to be sent to the motor driver of the CNC plotter.
Dueto the rapid growth of technology the usage & utilization of CNC machine inindustries are increased. The fabrication of low cost CNC machine is used toreduce cost and complexity of machine. This paper deals with the design ofautomatic mini CNC machine for PCB drawing and drilling. The Idea behind ourproject is to design and drill PCB based on low cost CNC system the lower costis achieved by incorporating features of PC with ATMEGA 328 controller in anarduino. We have use an G code for whole system operation G code is nothing buta language in which people tell computerized machine tools ‘How to makesomething’. The How is defined by instructions on where to move &how fast to move. KeywordsComputer Numerical Control (CNC), PrintedCircuit Board (PCB), G-code, Microcontroller Unit (MCU), Plotter.
CNC, Arduinocontroller, G code, FTDI, PL2303. 1.INTRODUCTION APlotter is a special type of printer that uses a pen to draw images on solidsurfaces. InComputer Numeric Control (CNC), microprocessor is used which is capable ofprocessing logical instructions interfaced with a computer. The logicalinstructions are provided by using a computer in the form of code or text orimage which is then transformed into a machine language by microprocessor to beexecuted by the machine. ACNC plotter machine is a 3D controlled 2D plotting machines which uses a pen todraw text or image on any given solid surface. It can be used for the purposessuch as PCB Design, logo design, etc. This project is based on CNC plottermachine.
With the increasing demand for the use of CNC plotters in universitiesand laboratories, a cheap and less complex design is an absolute need. Theparts used for the plotter in our project are easily available at a very lowprice and spare parts are also used. The construction is very simple androbust. CNC Machining is a process used in themanufacturing sector that involves the use of computers to control machinetools. Tools that can be controlled in this manner include lathes, mills,machines and grinders. The CNC stands for Computer Numerical Control.
Inspiringfrom this CNC technology and revolutionary change in the world of digitalelectronics & Microcontroller, we are presenting here an idea of CNC penplotter using custom built PLC. The idea behind this project is to make a smallCNC machine which can draw images or pictures on surface which can be a paperor anything. It uses three stepper motors as linear actuators on each axis X, Y& Z. While printing / drawing, the proper synchronization of all this threeaxis i.e. stepper motors, is most challenging task. At present the data to drawis given programmatically i.
e. hardcoded in program in binary format. A pentouches the surface & prints the pixel for logic 1 and lifts up in air forlogic zero & actuator changes it position for next commands execution. Asin future plan, it can access the G-Code directly from supporting software likeinkscape.
Presented plotter is one dimensional 1D plotter. 1.1 Objective The objectives of this project is to design and implement a CNC plottermachine (Drawing surface area 20cm x 20cm) which will be able to draw a PCBlayout (or any image) on a solid surface. 1.
2 MethodologyACNC plotter is able to draw complex line drawings. The coordinates are uploadedto the machine controller by aseparate program. The image file is transformed into a G-code via Software. Then the code is transferred to themicrocontroller by which the motor mechanism is instructed to draw the image. In this project, we are going topresent a simple design for a CNC plotter.
Our idea is an Arduino based designusing ATMEGA 328P microcontroller. The machine will have three motors toimplement the X, Y, and Z axis. A servo motor will be used along the Z axis forpositioning the pen which will go up for logic 0 and down for logic 1. Drawingwill be done on the X-Y plane where the positioning will be controlled bystepper motors.
2. BLOCK DIAGRAM A CNC plotter is able to draw complex line drawings. The coordinates are uploaded to themachine controller by a separate program. The image file is transformed into a G-codevia Software.Then the code is transferred to Fig -1: Block diagram the microcontroller bywhich the motor mechanism is instructed to draw the image In this project, weare going to present a simple design for a CNC plotter. Our idea is an Arduinobased design using ATMEGA 328P microcontroller. Fig -2: serial working 2.
3 ARDUINO UNO: Arduinois an open-source platform used for building electronics projects. Arduinoconsists of both a physical programmable circuit board (often referred to as a microcontroller) and apiece of software, or IDE(Integrated Development Environment) that runs on your computer, used to writeand upload computer code to the physical board MostArduino boards consist of an Atmel 8-bit AVR microcontroller (ATmega8 ATmega168, ATmega328, ATmega1280, ATmega2560) with varying amounts of flash memory, pins,and features. The boards use single or double-row pins or female headers thatfacilitate connections for programming and incorporation into other circuits.These may connect with add-on modules termed shields. Multiple, andpossibly stacked shields may be individually addressable via an I²C serial bus. Most boards include a 5 V linear regulator and a 16 MHz crystaloscillator or ceramic resonator. Some designs, such as the LilyPad, run at8 MHz and dispense with the onboard voltage regulator due to specificform-factor restrictions.
2.4Stepper motor Astepper motor is a brushless, synchronous electric motor that converts digitalpulses into mechanical shaft rotation in a number of equal steps. The motor’sposition can then be commanded to move and hold at one of these steps withoutany feedback sensor (an open-loop controller) .ANEMA 23 stepper motor is astepper motor with a 2.3 x 2.
3 inch size is chosen to drive the motion of theaxes. NEMA 23 stepper motors are high torque about 19KG-Cm holding torque .NEMA23 stepper motors have 1.8 degree step angle with 2.5A rated current.
The speedof rotation is directly proportional to the pulse frequency .The higher theoutput voltage from the driver, the higher the level of torque drive. 2.5 Easy drivers EasyDriver consist of 16 pins from which we are using in our project only 9 pins.Four pins are used for two stepper motor coil i.
e. coil A and coil B. Two pinsfor input 5volt supply i.
e. VCC and GND. Three pins are used for STEP, DIR, GND. STEP is used for micro stepping. DIRis direction input pin which will move stepper motor according to the givendimensions. Third pin is directly grounded.
3. PROCESS DESCRIPTION Main blocks of this system consists of power supply, FTDI module,ATMEGA328, 3 Easy drivers each connected to stepper motors X, Y, Z. From powersupply we get two voltages i.e. +5volt and +12 volt. 5volt which is required toATMEGA328, Easy drivers whereas +12volt supply is required to stepper motors.RESET is connected to5v supply through 10k ohms resistors to pull up thevoltage thus it act as a pull up resistors.
We have used here16MHz crystaloscillator connected to ATMEGA with two capacitors of 22pF.EasyDriver consists of 16 pins from which we are using in our project only 9 pins.Four pins are used for two stepper motor coil i.e. coil A and coil B. Two pinsfor input 5volt supply i.
e. VCC and GND. Three pins are used for STEP,DIR; GND.STEP is used for micro stepping. DIR is direction input pin which will movestepper motor according to the given dimensions. 4.
HARDWARE IMPLEMENTATION 5.CONCLUSION Thissetup of hardware with a combination of G-code gives better accuracy andreduces the work load. G code make easy to find the information of locations ofall stepper motor moving, as the status of our moving motor are directly seenon computer hence we can start or stop the machine whenever we are needed.Making a small machine brings an flexibility to do work. References 1madekar, kajal j.
, et al. “automaticmini cnc machine for pcb drawing and drilling.” (2016). 2linggarjati, jimmy, and rinda hedwig. “manually interchangeable headsof homemade computer numerical control (cnc) machine.” internetworkingindonesia journal 1.1 (2013). 3 m.
r. wright, d.e. platts, d.b. french, g.traicoff, m.a.
dupont, andg.a. head,”cnc control systempatents,” uspatent 545393, sep 26,1995.4 torjus spilling “self-improving cnc milling machine” university of oslo (2014) 5 neje 200mwmini diy laser engraving machine cnc laser printer 6 Industrialsuppliesonline.net/craftsman-cnc-router. 7 geocities.ws/industrialmarketplace/cnc-machines.
8 arduino.cc/en/Main/ArduinoBoardUno. 9 en.wikipedia.org/wiki/ATmega328.
10 dualfull-bridge driver. multiwatt15. ordering numbers : l298n (multiwattvert.) l298hn.