why CNC machining
manufactures complex/imposible jobs (2D and 3D contours)
- improve quality and accuracy
- stabilize costs
What does CNC mean
Computer Numerical Control
Product quantity, Q
(annual quantity)
Low production 1 to 100 units
Medium production 100 to 10,000 units
high production 10,000 to millions of units
Soft vs hard product variety
soft- small difference b/t products
hard - products differ a lot
what are the three basic types of automation
- hard (fixed) automation - fixed configuration
- programmable automation - allows for diff parts
- soft (flexible) automation - no lost production time when making changes
what is computer numerical control (CNC)
A form of programmable automation in which
the mechanical actions of a piece of equipment
are controlled by a program containing coded
alphanumeric data
what does the data represent in CNC
relative positions between a workhead (e.g., a cutting tool) and a workpart
What does NC operating principle control
the motion of the work head relative to the work part and to control the sequence of motions
What are the 3 components of a CNC System
- Part program - commands to be followed (cad converted to this )
- Machine control unit (MCU) - converts to assembly language (0 and 1)
- Processing Equipment - does the sequence of processing steps
What are the NC Coordinate systems
- 3 linear axes (x, y, z)
- 3 rotational axes (a, b, c)
*do not require all 6 axes and rotational is used to access different surfaces
What are the 3 basic categories of motion systems
- point to point
- straight cut control (continuous)
- Contouring (continuous)
what is the relation ship between speed and resolution
high speed - bad resolution
low speed - good resolution
what are benefits of cnc
- Reduced non-productive time
– Results in shorter cycle times - Lower manufacturing lead times (cad to manufacturing process)
- Simpler fixtures
- Greater manufacturing flexibility
- Improved accuracy
- Reduced human error
What are the 2 basic types of control in numerical control
- open loop system (no feed back - used for simple shapes)
- closed-loop control system (uses feedback to verify positions)
what does an optical encoder do?
improves accuracy and resolution
What do ball screws do
minimizes backlash
What happens if u have more axis
You have less resolution and accuracy (u do get more movement tho) - cost increases too - reduces machining time
interpolation idk
moving in 2 axis does not result in a straight line
