Overview Milling robots
Cutting, Drilling and Milling Robots
Cutting, Drilling, and Milling robots are the most common robot manufacturing applications for removing material. More and more we are finding industrial robots being used to perform milling and trimming operations where in the past particularly in the case of milling these were traditionally carried out by CNC machines. There are two major advantages of using a six-axis robot:The first ratio – “envelope against price” is low. In other words, it is possible to mill big things for not too much money. The second is the ability of the robot to mill from different directions including undercutting. By adding an external axis to the robot to provide a rotating turntable or positioner this allows milling most complex shapes.
Main Elements of Milling Robot Cell
1. Large capacity controller
Bear in mind that the controller needs the capacity to hold large programs, reaching as much as 20 or 30 megabytes for large milling projects. Because the tool paths will be created offline and no doubt consists of a large number of points reaching into the hundreds of thousands.
Allied with the robot we must consider if you require an external axis. The need to re-orientate the stock will largely dictate the need of this axis. Likewise, it allows the robot to work behind or to the side of the stock rather than having the robot “reaching”. Thereby, allowing the robot to work in a more rigid configuration of its axes.
2. Robot Spindle
Fitted to the robot will be some form of spindle to work the cutter. Invariably this will incorporate a tool changer to allow the use of different cutters through the milling operations. Therefore, the automatic exchange of the cutters takes place as part of the cutting program sequence. The spindle will need to be of sufficient power to work the largest cutter envisaged.
Allied with the spindle will be an inverter to vary the cutter rotation speeds. Therefore, the cutter speed will be under the control of the robot controller usually via an analogue output cabled to the inverter speed input.
3. Milling Tool Rack
The position to mount the tool rack is near the robot but out of the work area. Invariably it will have plastic forks to hold each of the cutters in their respective tool holders. Also, a switch is wired to the robot to indicate that a tool holder is present in the rack. When a tool change is called for the robot will come over to the tool rack to exchange tools.
4. Robot Safety Panel
It is essential to install a safety panel with cell control pushbuttons to control the complete cell. This panel is electrically connected to the robot controller. The panel will include the safety relays for the two safety circuits for both the robot and spindle. One circuit will be for the Estops, these will stop the robot in all modes. Then, the other will be for the cell access and this will stop the robot and spindle whenever the robot is in Auto mode. This mounting table for the parts or material needs to be very flat and well-fixed to provide a good reference when setting up the robot. Next, it is important to teach a coordinate system as a reference for the parts or stock placed on this table and later for transfer to the offline programming package.
5. Robot Milling Guarding
The cell will need some form of guarding which will form a room or enclosure to make sure that nobody is present whilst the robot is working in automatic. The guarding or room enclosure will have any access points protected by a two-channel safety system. It is important to integrate the system into the safety panel. Please bear in mind that the guarding or room enclosure would need to take into account the possibility of a tool burst.
Lastly, we would normally have some form of offline programming package to generate the milling paths from CAD data. This software runs on a laptop or PC separate from the robot. There are many different offline CAD-CAM packages available and the robots will work with all of them.
Milling Cell Package
Phoenix can help you to choose the right robot arm milling cell based on your requirements, part fixtures, safety components or any other tailored equipment for the automation. Also, we work with all robot manufacturers such as ABB Robot For Sale, KUKA Robot For Sale, FANUC Robot For Sale, and others. Contact us for a free consultation, if you require world-class customer support before and after the installation of the robot.