The setting up time and the operating time of the components machined in machining centres are considerably saved by using:

Explanation:

Automatic pallet changer:

Automatic Pallet Changer (APC) is a device that can automatically change the pallet to/from the machine to the pallet stand.

• A pallet is a movable & interchangeable part of a machine tool that helps to transport raw or finished parts from the machine in order to reduce downtime for part loading/unloading.
• The setting up time and the operating time of the components machined in machining centers are considerably saved by using an automatic pallet changer so option 3 is correct.
• There are three main types of pallet changers in most CNC machine tools – manual, automated, and robotic.

Manual pallet systems:

• The operator has to physically load and unload the pallet, with the raw/finished part, to/from a docking station located & mounted on top of the machine table.
• Of the three options, this is the most laborious and least automated version. However, you can still achieve a reduction of downtime with this system.

Automated pallet systems:

• These are normally built-into the machine and operated automatically by the machine itself.
• The human intervention comes from the loading and unloading of parts at the pallet station.

Robotic pallet systems:

• These usually utilize a robot to load and unload pallets.
• The robot is often able to serve one to multiple machines however, these are fairly costly and may not be pragmatic in cost-sensitive markets.
• Over time, the state of constantly improving technology may make such systems increasingly cost-effective.
• Such systems are often sought in locations with high labor costs or insufficient skilled manpower.
• Difficulties for such systems may arise whenever customized and very specific manufacturing needs are required.

Additional Information

Automatic Tool Changer (ATC): Tool Magazine is a device that holds a number of tools and can automatically index to enable ATC to pick the right tool and replace the used tool. 

• An automatic tool changer (ATC) is used in computerized numerical control (CNC) machine tools to improve the production and tool-carrying capacity of the machine.
• ATCs change tools rapidly, reducing non-productive time.
• They are generally used to improve the capacity of the machines to work with a number of tools.
• They are also used to change worn-out or broken tools.
• The main parts of an automatic tool changer are the base, the gripper arm, the tool holder, the support arm, and the tool magazines.
• Although the ATC increases the reliability, speed, and accuracy of a machine, it creates more challenges compared to manual tool change.
• For example, the tooling used must be easy to center, and easy for the changer to grab, and there should be a simple way to provide the tool's self-disengagement.
• Tools used in ATC are secured in tool holders specially designed for this purpose