CAD/CAM Subject-Mechanical engineering

1. Features of
CNC Machining Centers

2. CNC Machine Components
 Cutting Tool / Collet Caddy
– Very common to have 100 or
more diverse cutting tools
loaded into a collet caddy
– They are numbered for ease
of identification
– The operator must know the
common tools by simple
visual observation

3. Boxford Vertical Mill Cutting Tools
Collet Caddy # Tool in Collet (different lengths)
5 2mm end mill, ball end
6 2mm end mill, slot drill
3 4mm end mill, slot drill
4 6mm end mill, slot drill
1 8mm end mill, slot drill
2 25 mm end mill, facing cutter

4. CNC Bench Vise
Notice the smooth machined surfaces; be careful not to damage surfaces

5. CAM & X-axis Table Alignment
To machine a part
with CNC, the end of
the tool must be
known relative to the
bench vise, x-axis
table, or some other
fixed distance

6. Z-axis Arbor
 Keep the lands clean
and oiled
– A slight tilt will cause
noticeable cut
deformations
– Align the protrusions with
slots in the cutting tool
quick change adapter
body

7. Air Nozzle
Used for:
 Keeping cutting area
free of excessive
cutting debris
 Quick cleaning
 When supplied with
misting, provides
cutting tool cooling

8. End Mill / Facing Cutter
 Hogs off large amounts
of material
– Radius of cut very large
– Provides a known
surface from which to
measure from
– Requires workpiece to
be robustly supported
due to high torque
created

9. Quick Change End Mill Adapter
 Helps provide quick
changing of cutting
tools without having to
use complex setup
procedures

10. Power Panel
 Lockable On-Off Switch
 Circuit Breakers
 Power Cord

12. Control Panel
1. FEED HOLD
Acts as an interrupt control to the program when pressed, preventing
any further tool movement until canceled. During an Automatic cycle,
after canceling CYCLE START must be pressed to resume the cycle.
2. SINGLE BLOCK
With machine running in automatic mode controlled from the PC, this
allows the operation of only a single block (line) of the program at a
time to be toggled on/off. Press CYCLE START to proceed.
3. CYCLE START
This sets the machine in automatic mode and starts the machining
from the PC program. Also used to resume an Automatic cycle after
a FEED HOLD is canceled and to action the next line if Single Block
is active.

13. Control Panel
4. FEED SPEED CONTROL
Provides stepless control of tool feed speed in the X, Y and Z axes from 0 to 100%
in 10% increments.
5. JOG TABLE AXIS CONTROLS
These four buttons control manual movement of the table in the X and Y axes.
Move the table in the X axis while held pressed.
Move the table in the Y-axis while held pressed.
6. JOG HEAD AXIS CONTROLS
Move the head in the Z axis while held pressed.
Pressing this button together with any of the other six axis control buttons provides
rapid movement of the axes in the indicated direction.

14. Control Panel
7. MANUAL
When lit, machine is operated from control panel (Manual mode). Pressing MAN
puts light out and machine is controlled by computer (Automatic mode). Press
MAN again to revert to manual mode operation.
8. AIR MIST CONTROL
Switches on or off the optional air mist coolant when fitted.
9. DATUM M/C - PROGRAM ABORT
After initially powering up the machine and pressing the Power Reset button (23),
with the machine in Manual mode (Manual mode button lit) press to datum the
machine axes.
• With the machine in Manual mode, the machine can be re-datumed at any
point. This should always be done if a physical stall of the axes has
occurred.
•During an Automatic Cycle with a Feed Hold (1) active, pressing will Abort
the current job.

15. Control Panel
10. TOOL CHANGE
With auto tool changer fitted, press to change to next tool automatically.
11. TOOL RELEASE
Releases the tool holder from the spindle if fitted with the auto tool changer.
Guard door must be open and tool holder held.
12. WORK HOLDING UN-CLAMP
Controls un-clamping of workpiece in pneumatic work holder vice, when
fitted.
13. WORK HOLDING CLAMP
Controls clamping of workpiece in pneumatic work holder vice, when fitted.
14. DOOR OPEN
Controls opening of the automatic doors when fitted.

16. Control Panel
15. DOOR CLOSE
Controls closing of the automatic doors when fitted.
16. SPINDLE CONTROLS
These control the speed and direction of rotation of the spindle.
Spindle Forward - Pressing this button starts the spindle rotating
forward. Holding it down increases forward speed. Pressing and holding the
'Spindle Reverse' button reduces speed in the forward direction.
Spindle Reverse - Pressing this button starts the spindle rotating in
reverse direction. Holding it down increases spindle speed in reverse
direction. Pressing and holding the 'Spindle Forward' button reduces speed in
the reverse direction.
Spindle Stop - Pressing this button stops spindle rotation.

17. Control Panel
17. EMERGENCY STOP
Pressing this pushbutton stops all machine movement and
switches off the electronics, and the button locks in the
depressed position.
If the machine is in production, an appropriate message is
displayed on the PC screen.
The button must be turned to release it and the Hard Reset
button (23) pressed to enable the machine to be started. The
machine must be datumed using the Datum M/C key (9).
If the machine was performing a production cycle, the cycle
must be repeated from the beginning.

18.  The definition of DNC.
– “A system connecting a set of numerically controlled machines to a
common memory for part program or machine program storage with
provision for on-demand distribution of data to machines.”
– In DNC, several NC machines are directly controlled by a computer,
eliminating substantial hardware from the individual controller of each
machine tool. The part-program is downloaded to the machines
directly (thus omitting the tape reader) from the computer memory.