MACHINE TENDING
Workpieces loading and unloading automation can be carried out on a wide spectrum of production machines. In particular, CNC machining centers, forging presses, bend presses as well as on testing and inspection machines.
When handling workpieces, using an industrial robot, we have the possibility of direct work with much larger masses or dimensions of the workpieces. In addition, we get a much higher dynamics of movement than in case of human work with a balancer or an auxiliary hoist.
Loading and unloading of parts from machines, automation for CNC machining work cells, and reorientation of parts during the machining are basic advantages comes from robot. The efficiency of the CNC machining work cell, with the feeding of workpieces by industrial robot, allows you to speed up whole process up to 50%, especially when using the appropriate equipment or additional software on the machining device.
In robotized loading and unloading of machines, many types of working heads are used.
When choosing the type of head, there need to be taken into account: process dynamics, workpiece characteristics, limitations and requirements of the machining device.
Among the most commonly applied heads are used following:
- two or three finger mechanical heads,
- mechanical heads with a dedicated gripper,
- vacuum pneumatic heads,
- pulse controlled magnetic heads,
- electromagnetic heads with adjustable holding force,
- loading systems for machining palettes with fixtures and workpiece,
- systems for large-size workpieces, built from a set of grippers placed on supporting structures.
The basic way of exchanging signals between machines is the binary interface. Individual 24VDC physical signals are exchanged by using a set of relays or optical isolators mounted in both machines. This solution is applied in simple processes, where there is less information and the speed of signals exchange is low. Such communication can be used e.g. in loading for clamping spindle on the CNC machine or unloading the injection molding machine.
In processes where the number of signals exchanged exceeds over a dozen of basic signals or it is necessary for the robot to follow the tool movement, e.g. synchronization, industrial network communication interfaces are used. These interfaces may be based on standard networks or dedicated communication devices of machine manufacturer. Such communication will allow for synchronous robot operation, e.g. with a bend press or measuring machine, during the continuous robot’s movement following the tool.
Communication capabilities are often limited by the age of the machines or the possibilities to connect with original software of the machine. Buying new machines, it is worth pay attention to the available communication interface in the machine, in particular possibilities for integration with the robot.