COMPUTER INTEGRATED MANUFACTURING

1. BLU
BASIC LENGTH UNIT

3. LEADSCREWS
Leadscrew
Pitch
Nut
Converting the rotational motion of the motors to a linear motion.
pitch (p): the distance between adjacent screw threads
The number of teeth per inch (n):
n = 1 / p
BLU: Basic Length Unit (machine resolution)
BLU = p / N

4. Example
A machine has 1 BLU = 0.001".To move the table 5"
on X axis at a speed (feed rate) of 6 ipm. Calculate
pulse rate and pulse count.
• pulse rate = speed/BLU = 6 /0.001
• = 6,000 pulse/min
• pulse count = distance/BLU

6. Open Loop vs. Closed Loop controls

7. Advantages of CNC
- Easier to program;
- Easy storage of existing programs;
- Easy to change a program
- Avoids human errors
- NC machines are safer to operate
- Complex geometry is produced as cheaply as simple ones
- Usually generates closer tolerances than manual machines