Robotic machine feeding process efficiency in applications / Author: Hakan Eris
The main use of CNC machine feeding systems is to increase productivity. In order to increase efficiency, it is necessary to interfere with the machine as little as possible. Why is the CNC machine intervened?
In case of chip on the tool
In case of chips left on the chuck.
In case of frequent tool offset.
In case the workpiece is not properly clamped.
Chip Remaining on the Tool
Chip formation in chip removal technology does not always occur in the form of cut plates, depending on the type of material and machining parameters. Discontinuous chip formation is observed when machining brittle materials such as cast iron at low cutting speeds. Ductile materials form long and continuous chips at high cutting speeds, low feed and depth of cut. Since these types of chips do not move away from the environment and can get entangled in the tool, they must be broken and removed. Ductile materials heat up due to friction at low cutting speeds, resulting in a continuous chip with pile-edges that can stick to the workpiece. Long chips or chips sticking to the workpiece are not desired in robotic machine feeding systems. For this, first of all, the cutting tool and cutting conditions must be set properly. In addition, it is absolutely necessary to send high pressure cutting fluid on the tool in order to prevent chips on the tool and to ensure the cooling of the tool. CNC machine manufacturers keep the coolant pump pressure at an average of 1 bar. In cases where this pressure is not sufficient, the pressure should be increased.
Chip Remaining in the Chuck
It is a common situation that chips remain on the chuck feet during the machining of workpieces. In manual operation, after the operator picks up the workpiece, he keeps air on the chuck legs. This situation should also be applied in robotic machine feeding processes. For this, the robot must hold air to the mirrors after receiving the part. Especially in short operations, since this process corresponds to 10-20% of the total processing time, even for 3-4 seconds, there may be differences between the number calculated on paper and the actual number. Alternatively, air should be supplied to the mirror legs from the bench side. All CNC lathes have this feature as an option. But the seller or the user does not want this option so that the investment cost does not increase. It is a must-have feature in robotic bench feeding applications. The application company should add this option to the CNC machine.
Giving Tool Offset to the Machine
Depending on the type of material and the choice of cutting conditions, there may be changes in the dimensions of the parts due to the wear of the cutting tool. This is one of the important criteria affecting the efficiency of the machine in robotic machine feeding applications. The solution can be in two ways. If there is a fully automatic tool measuring system on the machine, the tool is measured automatically at certain intervals with experience and thus the tool offset is given automatically. If not, a measurement station is added to the system. The measuring station measures the part and gives the tool offset to the workbench according to the part values it measures.
Workpiece Not Connected Correctly
As it is known, band saws may not cut the part properly over time due to use, and may leave burrs on the part. This is undesirable in robotic bench feeding applications. Since the robot cannot see the part, the Burr prevents the part from being properly connected. In order to avoid this situation, the part should be connected properly by adding some mechanical additions to the Robot Gripper.