	Temperature Controller

	Liquid Level Controller

	Load Positioning System

	Laser Cutting Machine

	Motion Control System

	DC Motor controller

	AC Motor speed control

	conveyor belt control

~: Industrial Laser cutting machine :~

Abstract: - Laser is used to cut different metal sheets, glass, diamond and all other very hard things as this becomes very easy to cut using laser rather then using different blades. Its one kind of CNC machine in which two stepper motors displaces the laser to calibrated distance. As one enters the dimension of plate (L X B) the system calibrates the linear distance in terms of angular displacement of motor. Then rotates the motor 1 till the length of sheet. Rotate motor 2 till the breadth of sheet. Again rotate motor 1 in reverse direction and then rotate motor 2 in reverse direction to cut complete rectangle (or square).

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First let us understand mechanical arrangement for the machine.

Mechanical assembly: -

As shown in above figure, there are two stepper motors one is to move laser horizontally (motor 2) and other is to move is vertically (motor 1). The angular motion of motor 1 drives 2 main shafts through suitable gear arrangement. Again this horizontal drive shafts are coupled with two vertical shafts (shaft 1 and shaft 2) through suitable gear arrangement. Coupling used is 1:1 every time. Shaft 1 displaces motor 2 and at the same time on the other hand shaft 2 displaces movable supporting end. So as motor 1 rotates CW / CCW direction, the laser will move up n down (vertically means on Y-Axis). In same manner as motor 2 rotates CW / CCW direction, the laser will move horizontally (in X-Axis).

The relation between angular displacement of motor and linear displacement of laser is given as

5 rotation = 1 inch

So using this equation we can calculate the no of rotation of individual motor after we have the dimension (L X B) of sheet.

e.g. Is if we have to cut the sheet of 3' X 2' (foot), then 3 foot = 36 inch = 180 rotations. So motor 2 has to rotate 180 rotations. In same manner 2 foot = 24 inch = 120 rotations. So motor 1 has to rotate 120 rotations. So in complete operation as explained above

Motor 1 will rotate for 180 rotation in CW direction. So laser will cut the sheet in forward upto 3 foot
Motor 2 will rotate for 120 rotation in CW direction. So laser will move up and cut the sheet upto 2 foot
Now again motor 1 will rotate for 180 rotation in CCW direction. So laser will cut the sheet in backward upto 3 foot
And last motor 2 will rotate for 120 rotation in CCW direction. So laser will move down and cut the sheet upto 2 foot
So finally entire rectangle of 3' X 2' is cut from metal sheet.

Note:- The max capacity of the machine is to cut the sheet of 4' X 5'. The sheet cutting time is approx 10 sec / foot. So to cut the sheet of 3' x 2' it will take approx 100 sec.

Now after understanding the operation let us see system block diagram first.

System block diagram: -

The above figure shows major blocks of laser cutting machine circuit.

Keypad: - It is used to enter dimensions L and B. Its simple 4x3 matrix numeric keypad that has number 0 - 9 keys and one "enter" and one "start" key.

89C51: - For this simple system all you need is one micro-controller that is 89C51. This is the heart of the system that performs all following tasks

Accepts dimensions entered by user form keypad
Displays various messages on LCD
Indicates various events on LEDs
Rotates both motors as to move laser to calibrated distance

LCD panel:- Is just shows various messages like "Enter X" "Enter Y", "Press start" etc. To user

LED indicators: - It indicates the rotation of both motors in CW and CCW direction. The purpose it to find out any malfunction of motors or mechanism.

ULN2803: - Its 8 built in Darlington pair, used to provide enough current to stepper motors. Both the stepper motors are of 0.6 A / par phase. So out put of ULN can easily drive them.