The document discusses CNC machining centers. It defines a CNC machine center as an advanced manufacturing machine tool that can perform various machining operations with accuracy and quality. CNC machine centers allow operations like drilling, milling, and lathing to be done on a single machine. They are used to manufacture parts that require multiple operations, reducing production time compared to separate machines. CNC machine centers can be horizontal, vertical, or universal depending on the configuration, and include mechanisms like automatic tool changers to further reduce production time.

1. CNC MACHINING
CENTRE
Guided By :
H. K. Patel
Lecturer
Mechanical Dept.
VPMP Polytechnic
Prepared By :
Shrikunj Patel
Sem -6
ME – 1
Shift -1st
126540319070

2. What is CNC Machine Centre?
 CNC machine centre is advance
manufacturing machine tool which performs
wide range of machining operation with
accuracy and inspection free product with
good quality surface finishing.
 Operations done on drilling, milling and lathe
can be performed on CNC machine centre.

3. Why is CNC Machine Centre
Used?
 Manufacture of prismatic components like gear
boxes, bulkheads, frames, covers etc requires
different types of operations like milling,
boring, drilling, tapping and other many related
machining operations. Before the introduction
of CNC machines centers this operations
where done on different machines which leads
to considerable lead time for production. To
overcome this time problem CNC machine
centre where introduced which made possible
to do operations of milling, lathe and drill in
single machine tool.

4. Advance Mechanisms Used In
CNC Machine Centers
 Mechanisms used in CNC machine centre’s
main aim is to reduce production time.
Mechanisms used are as under:-
1) ATC (Automatic Tool Changer)
2) APC (Automatic Pallet Changer)
3) CNC Servo System
4) Feedback System
5) Re-circulating Ball Screw And Nut

5. Classification Of CNC Machine
Centre.
 CNC Machine Centers are classified according
to configuration as :
1) Horizontal Machine Centers
2) Vertical Machine Centers
3) Universal Machining Centers

6. Horizontal Machining Centre.

7. Horizontal Machining Centre.
 As the name says this machining centre has
horizontal spindle on which tool is mounted.
 This are generally single spindle machines
with automatic tool changer.
 ATC consist of a indexable tool magazine,
which can store several tools.
 The tool magazine can carry tool 16 to 100
tools depending upon its capacity

8. Horizontal Machining Centre.
 To reduce loading and unloading time
automatic pallet changer (APC) in installed.
 APC consists of 6,8 or more pallets.
 Work pieces can be set up in all pallets and
the machine can be programmed to accept a
new pallet when work on the previous pallet is
completed.
 The work piece may be different and may
require different programs.

9. Horizontal Machining Centre.
 Because of large material removal rate, the
cutting tool are normally big.
 So that tool magazine have large place for
each tool and its becomes heavier.
 Some machine centre have additional facility
for swiveling the entire spindle such that the
horizontal axis of spindle becomes vertical.
This features helps to a machine a fifth phase
apart from 4 faces.

10. Specification of a typical Horizontal
Machining Centre.
Traverses
Saddle – longitudnal
Spindle head – vetical
Column – cross
X-Axis
Y-Axis
Z-Axis
800mm
700mm
800mm
Feeds
Rapid traverse
Feed Rate
All axes
All axes
12000 mm/min
1-4000 mm/min
Spindle
Spindle taper
Speed
Range
Power
BT 50
Infinitely variable
20-400 rpm
15 kW (AC)
Accuracies: (JIS)
Positioning accuracy
Repeatability
+/- 0.005
+/- 0.0025
Automatic Pallet
Changer
No. of pallets
Pallets changing time
2 nos
40 sec

11. Vertical Machining Centre.

12. Vertical Machining Centre.
 In this category of machine tool, large variety
of job can be completed in a single setup.
 Most of vertical machining centre have three
axis and some have facility of spindle head
can be swiveled in one or two axis.
 This are required for machining of sculptured
surfaces.

13. Vertical Machining Centre.
 The major types of vertical machining centre
are as follows.
 Travelling column
 Gantry structure
 Multiple spindle
 Vertical Machining Centre are mostly useful for
tooling industry for machining of dies and
moulds.

14. Specification of Vertical Machining
Centre.
Effective Table Area (mm) 550*1400
Loading Capacity of table (kg) 1500
Travels (mm)
X-Axis
Y-Axis
Z-Axis
1000
550
550
Feed Rate (mm/min) 1-4000
Spindle Diameter (mm) 100
Tool Selection Random Memory
(Bi-Directional)
Automatic Tool Changer:
No. Tools
Max. Tool Weight (kg)
Max. Tool Diameter (mm)
40
15
1200*L400

15. Universal Machining Centre

16. Universal Machining Centre
 These are similar to horizontal machining
centers but with the spindle axis capable of
tilting from horizontal to the vertical position
continuously under computer control.
 This machine centers consists of 5 or more
axis.
 Such machines facilities access to the top
surface of work piece mounted on a horizontal
machining centre so that all the five sides of a
components can be machined in a single set
up.

17. Specification of Universal
Machining Centre.

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