ABSTRACT electronics laboratories, for electronics engineering students and

ABSTRACT

         
With the advancement of technology, demand for Computer Numerical
Control (CNC) plotter machines in Educational Institutions and Laboratories is
rapidly rising. Low cost manufacture of Printed Circuit Board (PCB) has become
a basic need in electronics laboratories, for electronics engineering students
and for electronics hobbyists. This paper will present an affordable model of a
CNC plotter machine which is able to draw a circuit layout on PCB or any other
solid surface using simple algorithm and available components. At first the
user needs to convert any image file or text file into G code using Inkspace
software and then feed it to the machine using Processing software. Arduino uno
with an ATmega328P microcontroller is used as the control device for this
project. The microcontroller converts G-code into a set of machine language
instruction to be sent to the motor driver of the CNC plotter.

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 Due
to the rapid growth of technology the usage & utilization of CNC machine in
industries are increased. The fabrication of low cost CNC machine is used to
reduce cost and complexity of machine. This paper deals with the design of
automatic mini CNC machine for PCB drawing and drilling. The Idea behind our
project is to design and drill PCB based on low cost CNC system the lower cost
is achieved by incorporating features of PC with ATMEGA 328 controller in an
arduino. We have use an G code for whole system operation G code is nothing but
a language in which people tell computerized machine tools ‘How to make
something’. The How

 

 

 

 

 

 

 

 

 

is defined by instructions on where to move &
how fast to move.

 

Keywords

Computer Numerical Control (CNC), Printed
Circuit Board (PCB), G-code, Microcontroller Unit (MCU), Plotter. CNC, Arduino
controller, G code, FTDI, PL2303.

 

1.
INTRODUCTION

 

A
Plotter is a special type of printer that uses a pen to draw images on solid
surfaces.

In
Computer Numeric Control (CNC), microprocessor is used which is capable of
processing logical instructions interfaced with a computer. The logical
instructions are provided by using a computer in the form of code or text or
image which is then transformed into a machine language by microprocessor to be
executed by the machine.

A
CNC plotter machine is a 3D controlled 2D plotting machines which uses a pen to
draw text or image on any given solid surface. It can be used for the purposes
such as PCB Design, logo design, etc. This project is based on CNC plotter
machine. With the increasing demand for the use of CNC plotters in universities
and laboratories, a cheap and less complex design is an absolute need. The
parts used for the plotter in our project are easily available at a very low
price and spare parts are also used. The construction is very simple and
robust.

     CNC Machining is a process used in the
manufacturing sector that involves the use of computers to control machine
tools. Tools that can be controlled in this manner include lathes, mills,
machines and grinders. The CNC stands for Computer Numerical Control. Inspiring
from this CNC technology and revolutionary change in the world of digital
electronics & Microcontroller, we are presenting here an idea of CNC pen
plotter using custom built PLC. The idea behind this project is to make a small
CNC machine which can draw images or pictures on surface which can be a paper
or anything. It uses three stepper motors as linear actuators on each axis X, Y
& Z. While printing / drawing, the proper synchronization of all this three
axis i.e. stepper motors, is most challenging task. At present the data to draw
is given programmatically i.e. hardcoded in program in binary format. A pen
touches the surface & prints the pixel for logic 1 and lifts up in air for
logic zero & actuator changes it position for next commands execution. As in
future plan, it can access the G-Code directly from supporting software like
inkscape. Presented plotter is one dimensional 1D plotter.

 

1.1 Objective

 

The objectives of this project is to design and implement a CNC plotter
machine (Drawing surface area 20cm x 20cm) which will be able to draw a PCB
layout (or any image) on a solid surface.

 

1.2 Methodology

A
CNC plotter is able to draw complex line drawings. The coordinates are uploaded
to the     machine controller by a
separate program. The image file is transformed into a G-code via  Software. Then the code is transferred to the
microcontroller by which the motor mechanism 
is instructed to draw the image. In this project, we are going to
present a simple design for a CNC plotter. Our idea is an Arduino based design
using ATMEGA 328P microcontroller.

        The machine will have three motors to
implement the X, Y, and Z axis. A servo motor will be used along the Z axis for
positioning the pen which will go up for logic 0 and down for logic 1. Drawing
will be done on the X-Y plane where the positioning will be controlled by
stepper motors.

 

2. BLOCK DIAGRAM

               A CNC plotter is able to draw complex line drawings. The coordinates are uploaded to the
machine controller by a separate program. The image file is

 

 

 

 

 

 

 

 

 

 

 

 

 

transformed into a G-code
via Software.Then the code is transferred to

 

 

 

Fig -1: Block diagram

 

the microcontroller by
which the motor mechanism is instructed to draw the image In this project, we
are going to present a simple design for a CNC plotter. Our idea is an Arduino
based design using ATMEGA 328P microcontroller.

 

Fig -2: serial working

 

2.3 ARDUINO UNO:

 

        Arduino
is an open-source platform used for building electronics projects. Arduino
consists of both a physical programmable circuit board (often referred to as a microcontroller) and a
piece of software, or IDE
(Integrated Development Environment) that runs on your computer, used to write
and upload computer code to the physical board

 

Most
Arduino 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 that
facilitate connections for programming and incorporation into other circuits.
These may connect with add-on modules termed shields. Multiple, and
possibly stacked shields may be individually addressable via an I²C serial bus. Most boards include a 5 V linear regulator and a 16 MHz crystal
oscillator or ceramic resonator. Some designs, such as the LilyPad, run at
8 MHz and dispense with the onboard voltage regulator due to specific
form-factor restrictions.

2.4
Stepper motor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A
stepper motor is a brushless, synchronous electric motor that converts digital
pulses into mechanical shaft rotation in a number of equal steps. The motor’s
position can then be commanded to move and hold at one of these steps without
any feedback sensor (an open-loop controller) .ANEMA 23 stepper motor is a
stepper motor with a 2.3 x 2.3 inch size is chosen to drive the motion of the
axes. NEMA 23 stepper motors are high torque about 19KG-Cm holding torque .NEMA
23 stepper motors have 1.8 degree step angle with 2.5A rated current. The speed
of rotation is directly proportional to the pulse frequency .The higher the
output voltage from the driver, the higher the level of torque drive.

 

 

 

 

 

 

2.5 Easy drivers

 

Easy
Driver 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 pins
for 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 move stepper motor according to the given
dimensions. 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 power
supply we get two voltages i.e. +5volt and +12 volt. 5volt which is required to
ATMEGA328, Easy drivers whereas +12volt supply is required to stepper motors.
RESET is connected to5v supply through 10k ohms resistors to pull up the
voltage thus it act as a pull up resistors. We have used here16MHz crystal
oscillator connected to ATMEGA with two capacitors of 22pF.

Easy
Driver 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 pins
for 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 move
stepper motor according to the given dimensions.

 

4.
HARDWARE IMPLEMENTATION

 

 

 

5.
CONCLUSION

 

This
setup of hardware with a combination of G-code gives better accuracy and
reduces the work load. G code make easy to find the information of locations of
all stepper motor moving, as the status of our moving motor are directly seen
on computer hence we can start or stop the machine whenever we are needed.
Making a small machine brings an flexibility to do work.

 

 

 

References

 

1
madekar, kajal j., et al. “automatic
mini cnc machine for pcb drawing and drilling.” (2016).

2
linggarjati, jimmy, and rinda hedwig. “manually interchangeable heads
of homemade computer numerical control (cnc) machine.” internetworking
indonesia 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,” us
patent 545393, sep 26,1995.

4  torjus spilling “self-improving cnc milling machine” university of oslo (2014)

 

5  neje 200mw
mini 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  dual
full-bridge driver. multiwatt15. ordering numbers : l298n (multiwatt
vert.) l298hn.