Introduction: Laser CNC Machine
The aim was to develop a cutting-engraver CNC
laser, CNC stands for computer numerical control, computer acts as the controller of the machine in wich is programmed through an interface following the instructions.
The need of productivity become a priority, besides accuracy and reduce drawbacks like: lack of skilled labor, lots of wastage, and non-expected results.
Initially the team got trained about the CNC programming for one month, the design is loaded to a computer wich is attached to the CNC laser, it changes the design into a special code(numerical)that controls the way the CNC operates.
The electronics consists of a separate power supplies for laser, motors and the Arduino which breaks input-output signals for the motion and laser control. The motion works through rubber conveyor belts that are linked by bearings to the motors that make them go on X and Y axis.
Finally it was decided to use wood for the base as it is economic and malleable.
Key Words— CNC Laser, G-CODE, Stepper Motor, Arduino, Driver A4988.
Step 1: Design
We opted for the design of a CNC by transmission by bands. The design was done in SolidWorks. The area designated for the working area was 32 x 28 cm, the base in this case are 4 pieces of wood 30 x 2 x 2 cm and in addition to the use of 4 smooth steel bars for movement; said bars have dimensions of 30 cm x .8 mm in diameter.
Step 2: Driver
Once the design with all the required specifications was made, the 4 bars of the base were ordered to be built. After this we started with the printing of the required 3D parts.
The test of the motors was carried out with the aid of the A4988 driver, but before this, the current of the same one as specified by the manufacturer was limited to avoid problems in both components, the formula to obtain this is:
ITripMAX = VREF / (8 × RS)
Where RS refers to the value of the resistors in S1 and S2, therefore, taking into account that the PAP motors are 0.4 A, the clearance would be this way:
VREF = 0.4 (8 × 0.1W) = 0.32 volts
When this value was reached, the potentiometer of each driver was adjusted.
Step 3: First Test (Stepper Motors)
After properly adjusting the driver, the program was loaded with the GRBL library to our Arduino Mega and connected to the software "CNC Controller" to start some tests with the Stepper motors and the interface.
Once the correct operation of the motors was verified with the basic commands in code G that was sent through the interface, the PCB began to be constructed with all the external components that would be used to begin the assembly of the same one.
Step 4: Base
Then, the base of the machine was started, starting at the top, which had an internal area of 28x32 cm, each side 2 cm thick, after which the holes were made to place the 3D pieces .
Then, the steel rods were cut to the required size, in this case one of 28 and one of 27.8 cm. The LM8UU bearings were then placed between the rods and the 3D filaments and greased for quicker and effortless movement to finally place them on the main base.
Step 5: Placement of the Laser and Band
Immediately, the F624ZZ bearings were installed in the 3D parts using nuts and bolts.
Later the installation of the 2 motors was realized, screwing them with screws in the main part of the base and placing the axis for the later placement of the band. 2 pieces of band were cut for the placement of the 2 axes, and the ends were joined with belts, after corroborating that had a movement in the axes optimum thanks to the band. The installation of the laser was continued in the centerpiece of the machine and the source of the machine was accommodated with cinches. Finally the mechanical structure was finished placing 4 supports and a base.
Step 6: Final Test
Once the mechanical part was finished, it was advanced in the electronic board where the A4988 drivers and the relay were placed for an easy assembly. Then the first tests were carried out in Inkscape software, to transform an image into a vector G code, set the measurements of the file in mm, which would be the limits of the drawing, then upload the file to the software CNC Control, then the GRBL program is uploaded to our Arduino, we connect the software to the microcontroller and start the engraving process.