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How can you reduce the time spent on producing a single unit and increase production volumes without compromising quality? Process automation helps here, which is increasingly used to streamline smaller tasks. This includes the automatic tool change system on CNC router machines.
What is an ATC
To replace the tool, you need to use wrenches to unscrew the nut holding the chuck, catch it, make the replacement, then insert it back and tighten the nut. After that, you have to find the correct zero point on the Z-axis again. The process isn’t very lengthy, but it is time-consuming.
This led to the development of a pneumatic system that removes the wrench step; now, you can simply press a button, and the chuck is released from the pneumatic clamps. However, you still need to replace the tool manually.
And to make the process even easier, an automatic tool change system was developed, where you don’t need to do anything at all—just set the required tools in the program, and the machine will automatically replace them for the production tasks. Convenient!
The ATC is being used, when:
- Different types of material processing are required on a single CNC router machine. For example, switching from milling to grinding;
- A composite part is being produced, meaning it’s made from several different materials;
- There is tool wear or breakage during operation. However, to avoid that happening way too often, you should follow the maintenance rules.
Work principle of the automatic change
It can be broken down into four main steps:
1. A control command is sent from the controller.
2. The spindle with the tool moves to the necessary position for tool change, which can vary depending on the type of ATC used.
3. The tool is being changed.
4. The spindle returns to its starting position, ready for operation.Speaking of types, there are many different ATCs. First, there’s a division based on what exactly is replaced: the entire spindle assembly or just the tool. There are also combined options. Then, there’s a division based on how the replacement is carried out. We won’t go through them all, as there are more than ten types; we’ll only cover the most popular ones.
Types of the ATC
Carousel tool change
This type of ATC is mounted directly on the gantry near the spindle. It uses a rotating mechanism that brings the attached tools into the working area. With this design, the instrument can be changed anywhere on the table. Such a turret can hold up to 12 tools.
Multi-Position Linear Supports
Linearly arranged holders with tools are located at the edge of the work area. When a tool change is needed, the gantry moves to this area to make the switch.
This mechanism is used in Wattsan routers. It was chosen because this ATC system does not add extra weight to the gantry, allowing precise and quick work without issues. Additionally, it reduces equipment cost: a heavier gantry would require a more powerful kinetic system to maintain optimal speeds.
Chain-type
In this case, tools are on special holders positioned one above another and fixed on a toothed belt or chain. The machine moves the tool toward the grippers for the change.
Tool sensor
This is an important feature that must be checked for presence if you’re purchasing a CNC router machine with an automatic tool change system. The thing is, each tool has its own length, and the routing or other operational program is written with this length in mind.
To ensure accurate operation, the Z-axis data must be updated every time the tool changes. This is where a sensor comes into play, so you don’t have to do it manually. The machine brings the tool to a metal plate, measures it, and updates the Z-axis information. This simplifies the tool change process.
CNC router machines with ATC
There are various machines with automatic tool change systems. Wattsan offers the model 1325 M3, which includes an ATC system.
In its standard configuration, the machine comes with a linear tool changer, but a carousel option is available upon customer request. The magazine holds up to 8 tools.
This CNC router machine is suitable for processing materials such as wood and wood composites, various plastics, soft metals like aluminum and brass, and more. It has a 7.5 kW spindle, making it capable of handling all these materials with ease. The collet chuck is ER-32, suitable for tools with a shank diameter of up to 20 mm.
The working table is 1300×2500 mm, and the gantry height is 300 mm, allowing for the processing of large workpieces or the installation of a rotary device if needed.
Wattsan 1325 M3 is used for light industry, interior and exterior decor, advertising production, metals and stone processing, and, mainly, for woodworking and furniture.
Conclusion
- The ATC system is designed to make the operator’s job easier and speed up production without sacrificing quality. It’s useful when the CNC machine router performs tasks of different profiles or processes composite workpieces made of several materials. The automatic tool change system also allows quick replacement of a broken or worn tool.
- There are many types of tool changers, generally differing by the system’s positioning relative to the spindle and work area. The most popular types are the carousel, linear, and chain-type ones.
- The process can be reduced to four sequential actions: first, a control command is sent from the controller, then the spindle with the instrument moves to the required tool change position, the tool is changed, and the spindle returns to its original position, ready for operation.
- For a more seamless experience, it’s best to have a tool sensor that enables the machine to automatically adjust the Z-axis position.
