Tool Changing Mechanism in CNC Machine

1. TOOL CHANGING
MECHANISM IN CNC
MACHINE

2. INTRODUCTION
A simple CNC machine will be made to work with a
single tool. More complex machines are capable of
working with larger numbers of tools. However, for a
machine to use more tools an ATC must be provided.
The array of tools are stored within a magazine which
allows the machine to access a wider variety of them
without the need for an operator.
ATC is used to improve both the production and the
tool carrying capacity of a computerised numerical
control or CNC machine tool. It does this by allowing
the machine to work with various different tools. As
such it is part of the process to achieve full
automation.

3. Types of Automatic Tool Changer
1) Tool-changing Mechanisms on Turning Center.
2) Drum-type tool-storage.

4. improvements of atc
 ATC increases the machine tool’s productive time.
 It significantly reduces the times for changing worn
tools.
 It provides storage of the cutting tools, which are
returned automatically to the machine tool after
carrying out the required operations.
New cutting tools are automatically delivered to the
machine by the tool-changing system.
The rotating magazine holder can provide tool-storage
capacities ranging from 60 to 240 cutting units, with up
to 24 different types of tool geometries.

5. AUTOMATIC TOOL-CHANGING MECHANISMS ON
TURNING CENTER.
• Cutting units can be stored in either a drum or a disc type of
storage device. A typical example of the storage facilities and
their automatic tool-changers. The rotary tool-changer swivels
between the tool magazine and the machine’s turret. Each
gripper can rotate through 90o, to deliver tools to the front
face of the turret. The tool-changer simultaneously removes
the cutting tools from the disc magazine and the turret and
then it rotates through 180o.
• The new tool is delivered to the turret and accurately
positioned in the correct orientation, whilst the used tool is
replaced in its correct turret position for either re-use or
replacement. The tool-changer arm is withdrawn from the
working area of the machine and starts the cutting cycle. A
gantry-type of tool-changer with a twin-gripper assembly can
be used for high-speed tool-changing where space in the
area of the machine is limited.

6. CHARACTERISTICS
Magazine should be capable of storing required
nos. of tools to carryout all the operations on a
machining centre.
 It should be compact and simple to reduce its
cost and space requirement.
 It should not be protruding the working space of
the machine for preventing it from disturbing tool
space at the time of tool changing.
It should allow manual transfer of tool easily and
safely at the time of loading and unloading the
tools.

7. ACTUAL SETUP OF AUTOMATIC TOOL CHANGER

8. Automatic Tool Changer Mechanism
 After receiving the tool change command, the tool to be changed
will assume a fixed position known as the "tool change position".
 The ATC arm comes to this position and picks up the tool.
 The arm swivels between machine turret and magazine. It will
have one gripper on each of the two sides.
 Each gripper can rotate 90°, to deliver tools to the front face of the
turret. One will pick up the old tool from turret and the other will pick
up the new tool from the magazine.
 It then rotates to 180° and places the tools into their due position.

9. ADVANTAGES OF AUTOMATICTOOL CHANGER
1) Low Skill Requirement: CNC machine operators require
little training and skill when compared to manual machine
operators.
2) Capability: This technology uses computer precision to go
beyond the limitations of manual capabilities. More complex
and intricate operations are possible with CNC machining.
3) Continuous Use: Unlike manual labor, CNC machinery
(barring any malfunction or maintenance issue) can work
continuously over any period of time without a break. This
greatly increases productivity and efficiency.
4) Consistency and Precision: With computer software, the
design of any given product only needs to be programmed
once. The CNC machine can then perfectly replicate that
design, for any order quantity.

10. DISADVANTAGES OF AUTOMATICTOOL CHANGER
1) Cost: CNC machines are more expensive and require a
greater initial investment than machines that can be operated
manually. However, as this technology becomes the standard,
supply is increasing resulting in costs gradually decreasing.
2) Skills Loss: As the demand for manual machine operators
decreases, fewer and fewer new students adopt those skills.
This could eventually lead to the complete loss of long-
preserved skills.
3) Unemployment: Automation decreases the need for
manpower, and fewer laborers are hired. That said, the need is
now shifting to software engineers and mechanical engineers,
and education and training will have to adjust to meet that need.
For more information on the skills gap in the manufacturing
industry, reference this blog post.

11. conclusion
Automatic tool changer is often used to improve
tool carrying capacity of CNC machine. CNC
machine with automatic tool changer increases
the machine tool’s productivity time reduces the
times for changing worn tools. The utilizations of
tools and machines and throughput of each part
type are three important performance measures
that must be managed for efficient production.