Schmid Technology Systems has a new technology for handling printed circuit boards in electronics production: a six-axis robot supplements the linear systems used so far. A "triflex R" energy chain from igus supplies the energy and signals to the robot gripper.
The Schmid Group, headquartered in Freudenstadt, specialises in the development and manufacture of machines for photovoltaic and printed circuit board production. Schmid Technology Systems in Niedereschach is the centre of competence for handling technology. The product range of this subsidiary includes loading and unloading systems. These systems separate, for example, printed circuit boards that are arranged on cartridges and feed them to a processing station via a conveyor belt.
The ever higher processing speeds and the customers' demand for greater flexibility led to the development of a whole new generation of handling systems. While linear units were previously used to move the individual axes, a six-axis robot is now being used for the first time that can load and unload cartridges with printed circuit boards with cycle times of less than seven seconds. More important than speed, however, is the flexibility of the system. As the robot can be freely programmed, a wide variety of motion patterns are possible - without any modifications or interventions in the hardware. For example, cartridges of different inclination angles can be loaded and unloaded. The system is completely enclosed because the highest demands are placed on purity when handling printed circuit boards. Therefore, compactness plays a major role - in cleanroom technology, one reckons with cubic centimetres.
An interesting detail of the system is the gripper, which automatically detects the size of the respective PCB. The support plate with the vacuum grippers is made of weight-saving carbon fibres so that you can use a compact 16 kg robot and move handling goods weighing up to 7 kg.
For the design engineers, the challenges of the system also raised the question of the optimal guidance of energy, control signals and compressed air to the gripper. The robot has an internal power feed-through, but there is not enough space for all the cables. In their search for an external energy supply system, the designers came across the multi-dimensionally movable triflex R energy supply system from igus. This energy chain was designed and developed especially for robotic applications. It is multi-dimensionally movable and adapts to all movements in the sixth axis, even with more complicated handling tasks for the robot. Small bend radii create the prerequisite for space-saving installation. At the same time, external stop-dogs for radius and torsion ensure that the defined radii do not fall short of the minimum bend radii and thus a long service life of the cables can be guaranteed.
The energy chain is also made of extremely abrasion-resistant material that has the necessary classifications for cleanroom technology.
igus supplies the triflex R energy chain of the new handling system as a ready-to-install harnessed readychain energy chain system, each with a harnessed servo cable and a resolver cable (for the two Bosch Rexroth and Indramat servo drives), two compressed air cables and a bus cable for the control signals.
The new system is convincing not only technically, but also economically. The robots have become much more cost-effective in recent years, and the availability of the robot is much higher compared to the linear units. Costs are also saved in the energy supply system because only one energy chain is needed instead of six.
For the new handling system, igus (corporate mission: "plastics for longer life") not only supplies the energy supply system. The lead screw drive of the complex gripper is mounted in an iglidur plain bearing made of high-performance plastics with permanently "built-in" lubricant. This offers several advantages over conventional ball bearings: it saves weight, does not require separately supplied lubricants and can be sure of having a long-lasting and abrasion-resistant bearing system that is maintenance-free. At the same time, the lubrication does not release any components into the environment: in this way cleanroom conditions are maintained. Schmid has a lot of experience with this type of bearings. In other machine series, which are developed and built in Niedereschach, more than 100 iglidur plastic plain bearings already ensure smooth motion sequences - in the truest sense of the word ...