Sunday, 1 June 2014

Team BangaloreRobotics - Deepak Narayanan

THESIS FOR LASER CUTTING/ENGRAVING MACHINE – OPEN SOURCE
                                                                         - Team BangaloreRobotics

INTRODUCTION

An Arduino controlled CNC LASER ENGRAVER/CUTTER:

We recently made a CNC Laser Engraver/ Cutter. The controller of the CNC machine is Arduino. This was a very challenging and also a sophisticated project. The dimensions of the machine are 1524*914*350 (all in mm). The power of the laser used in this project was 100W. This became one of the most successful project and we want to share it with everyone.

                                                             

ARDUINO BOARD(pic)


The reason we did this project was to bring a unique progress in the field of Robotics and show the world that how the knowledge of Electronics & Electrical, Mechanical and Software can be combined to design and build something fascinating. This has been a stepping stone for our career.

WARNING & PRECAUTIONS:
As this is one of the most interesting projects, we would suggest you to think several times before making it. And this must be done under the guidance and supervision of an expert. Working with a LASER is very risky. A ray of laser which has a power >50mW can cause permanent damage to your eyes, or may be to your skin accidentally. But here, we are talking about 100W LASER. Probably now you must understand the magnitude of the damage. DO NOT ALLOW KIDS, PETS OR ANY BEGINNER NEAR THE LASER. As a precaution wear a pair of SAFETY GLASSES for the suitable wavelength of the laser or you could attach a CAMERA inside and monitor the working on a screen, which we would suggest it as the most ideal and safe method.



STEP 1: THE HARDWARE

The frame which you see in the pictures is made of aluminum. The dimensions are 1524(length)*914(breadth)*350(height) all in mm. the workspace we have allocated is around 900*600 both in mm. They are welded at the joints. Basically, this looks like a cuboid and the rest of the assemblies will be fit exactly into this frame.


The frame which you see in the pictures is made of aluminum. The dimensions are 1524(length)*914(breadth)*350(height) all in mm. the workspace we have allocated is around 900*600 both in mm. They are welded at the joints. Basically, this looks like a cuboid and the rest of the assemblies will be fit exactly into this frame.



STEP 2: X-Y PLANE

                                                                         


                                                 Y-PLANE

                                                                              

                                                                     
                                                  X-PLANE

The plane that has a back and fro movement is the Y-Plane and the X-Plane is mounted on the Y-Plane, this has a horizontal movement.


STEP 3: MOTORS AND DRIVERS




The motors used in this are NEMA 23. They are 3 phase stepper motors. Each motor has a driver for its respective axis.  The 3 phase motors are really powerful motors. The details about the motors are given below.
No. of motors required – 2
Step angle – 1.8o
Step angle accuracy - ± 5%
Resistance accuracy - ±10%
Inductance accuracy - ±20%
Holding torque – 10kg
Length – 51mm



STEP 4: SETTING UP THE LASER TUBE



The laser tube is a very delicate thing. It must be handled with a great care, a small crack on it could make the whole tube a waste. The tube will be placed on the tube holders and has to properly aligned.

WORKING:

On one end of the tube, from where the laser beam comes out, a mirror is fixed there. The mirror has to be aligned at an angle of 45o, so that it reflects the beam to the second mirror. The second mirror must also be aligned at angle of 45o so that beam goes to the third mirror, which is located in the nozzle. After the beam reflects from the third mirror, the beam is reflected vertically downwards into a Plano-convex lens. And we get a clear focus of the beam on the surface. The alignment has to be done with help of an expert.


MIRROR 1 (BURNT PAPER DUE TO THE POWER OF LASER­­­)



MIRROR 2


MIRROR 3

STEP 5: ELECTRICAL SETUP

LASER SETUP:



The above shown is the setup for the connection between Laser power supply and Laser (DSP).



In the above picture shown, the stepper motors are connected to its respected axis drivers.

STEP 6: MECHANICAL SETUP



The aluminum sheets are covered on all the sides of the frame. These sheets protect the laser ray to go out and also give a complete look to the system. There is a water pump used, the water travels through the laser tube, acting as the coolant. On the other hand there is an air pump used which is connected to the nozzle, when the laser is on it blows away the fumes with a jet of force, so that the lens inside is protected and does not get clouded.


STEP 7: POWER SUPPLIES




The Laser needs a power supply of 220V. The power consumed by each stepper motor is 2.3V and 2.8A current maximum. The main board that controls the stepper motor is Aurdino. A H- bridge or a GRBL shield is connected to the Arduino board, the GRBL shield controls the motors.

STEP 8: SOFTWARE

The main software we used was PHCAD and Inkscape. Follow the steps below.

1. Open Inkscape and create a workspace of the required dimension.


2. Type a text or import the file to be plotted.


3. Select the text and click on Object to path






4. Click on Laser









 5. Create the output file in .nc format



6. Finally,

STEP 9:Gcode Sender


1. Select the required Port.

2. Browse for the .nc file and click on Print


STEP 10: OUTPUT ENGRAVINGS AND CUTTINGS






ACCIDENT:



























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