CNC MACHINES IN SHORT

1. NAME :- KRUNAL K. CHAMPANERI
SUBJECT :- CAM
ENROLL NO:- 156050319004
BRANCH:- MECHANICAL (SFI)
COLLEGE :- B&B INSTITUE OF TECHNOLOGY
CNC AXES AND MOTION
NOMENCLATURE

2. Different CNC Machine tools
A typical 3-axis CNC Gantry Machine
 Moves above the stationary work piece (part)
 Spindle moves at 90 0 in/out of the part
A typical CNC lathe machine tool
 Slides along the part
Multi-axis CNC Machines
 Rotary motion of spindle
Stationary CNC machine, but tool is allowed to move
in different direction

3. Axis and Motion Nomenclature
 Cartesian System
• Machine coordinate system is described based on
Cartesian system
• A Cartesian coordinate system is a coordinate
system that specifies each point uniquely in a plane by
a pair of numerical coordinates, which are
the signed distances to the point from two
fixed perpendicular directed lines, measured in the
same unit of length.
• Each reference line is called a coordinate axis or
just axis of the system, and the point where they meet
is its origin, at ordered pair (0, 0).

4.  The coordinates can also be defined as the positions
of the perpendicular projections of the point onto the
two axes, expressed as signed distances from the
origin.
 In this system, use Right-hand Rule
to designate the primary axis of
the machine tool.

5. Right Hand Rule of Coordinates
• Right Hand Rule of Coordinates, hold the thumb,
forefinger and middle finger at 90 degree, to each
other.
• Thumb (x-axis), Forefinger (y-axis), and Middle
finger (z-axis), each finger points +ve direction of
motion of the CNC tool motion
of the CNC tool.
• In 3-axis CNC milling machine,
the longest travel slide represents
the x-axis, each finger points to
+ve direction of motion of the CNC
tool, the z-axis points into the spindle

6. CNC Lathe Axes Nomenclature

7. 3-Axis CNC Milling Machine

8. Positioning System
 Two type of positioning system
1. Absolute system
2. Incremental system

9. Absolute System
 Absolute positioning always tells the controller where
to send the cutter relative to the origin.
 The controller always knows where the cutter currently
is located, so it can calculate the distance and direction
it must send the cutter to arrive at the desired
destination.

10. Incremental Positioning
 Incremental positioning always tells the controller
where to send the cutter relative to the cutter's
current location.

11. References
 http://faculty.etsu.edu/hemphill/entc3710/nc-
prog/nc-02-01.html.
 https://en.wikipedia.org/wiki/Cartesian_coordinate
_system.

12. Thank You