What Is a Tool Changer?
Tool changers are tool/tool changing mechanisms and systems used to add tool and tool changing functions to machine tools (e.g. machining centres) and industrial robots.
The tool/tool can be automatically attached and detached by operating a pneumatic valve. In addition to the tool loading/unloading, some tool changers are also equipped with an air blow function to remove dust from the tool clamping area.
Some tool changers can supply compressed air, water or electrical signals to the tool.
Uses of Tool Changers
Tool changers are used in machine tools and industrial robots.
1. Machine Tools
In machine tools, tool changers are useful for automatic machining of various tasks without the need for manual tool changing. Tool change programmes are set up in advance in the machining programme (NC programme: numerical control programme), and tool change, tool height measurement and run-out measurement are carried out automatically.
This reduces the need for human operatives to change tools, check tool height and tool run-out after tool change, and also enables fully automated machining of parts by automating the loading and unloading of parts.
2. Industrial Robots
In industrial robots, the hand changer is generally used to change the hand at the end of the robot. Robot hands have a wide variety of functions, such as gripping with an air chuck, rotation with a motor, vacuum suction, etc.
For this reason, tool changers are available for industrial robots that can supply compressed air, water, vacuum or electrical signals to the tool. Tool changers make it possible to perform several types of tasks with a single robot, thereby increasing the efficiency of industrial robot use.
Principle of Tool Changers
There are many different types of tool attachment and removal methods, each company’s own, but the majority use compressed air to clamp or pull the tool in place. On machine tools, pneumatic pressure is commonly used to secure the tool by pulling up a knob on the tool’s mounting.
Many tool mountings are tapered, and contact with the taper maintains repeatability of the tool position. Tool stockers are also referred to as ATCs (auto tool changers) on machine tools and are treated as a single system. There are various types of stockers.
For industrial robots, each company has its own compressed air-driven clamping mechanism, often using cams. Robot hands are designed by automatic machine manufacturers to suit the application, and stockers are manufactured accordingly, so few are sold as standard products.
Types of Tool Changers
There are many different types of tool changers. Common tool changers include:
1. Manual Tool Changers
This is the most basic type where the operator changes the tools manually. This requires the operator to access the machine, remove the tool and install a new tool.
2. Automatic Tool Changers
This is a tool changer capable of changing tools automatically. The machine changes the tools according to a pre-programmed procedure. When simply referred to as a “tool changer”, this is often what is meant.
3. Tool Changer With Robotic Arm
This type of tool changer uses a robot arm to change tools. The robot arm can remove tools and install new tools according to a predefined procedure.
4. Multi-Spindle Tool Changer
Tool changers are used on machines with multiple spindles (rotary axes). This allows multiple tools to be changed at the same time.
5. Tool Changer With Vision Guide.
This type of tool changer uses sensors or vision systems to detect the exact position and condition of the tool and select the appropriate tool. This allows a high degree of automation and accurate tool selection.
The above are examples of common tool changers, but many other variations exist, depending on the actual application and industry.