Festo offers low-cost load/unload SCARA-type system for machine builders

The subsystem is capable of performing similar types of loading and unloading movements as many industrial SCARA robots, with comparable performance, but at less than half the cost. Ideal for parts handling and positioning applications, the new EHMB module features a unique decoupled design, enabling the rotary and lifting movements to be controlled completely independently, for exceptionally fast and accurate positioning. The smaller size 20 model can accommodate payloads of up to 3 kg, generate more than 3 Nm of torque and handle moments of inertia as high as 30 kg/cm/cm. It is ideal for providing the integral Z movement in portal and cartesian parts handling systems. The larger size 25 model is more suited to stationary use, such as in loading, unloading and stacking applications. Capable of accommodating payloads as high as 5 kg, it can generate 8.8 Nm of torque and handle moments of inertia of up to 100 kg/cm/cm. Both modules offer a choice of 100 mm and 200 mm stroke lengths, and are capable of generating up to 480 N of lifting force. Users may also tailor the price/performance of the motion subsystem by choosing to use a motor and electrical actuator for the two axes, or a motor and pneumatic cylinder. Festo's modular EHMB design can be configured with a range of the company's positioning cylinders, motors and controllers. The rotary axis is always actuated electrically using a stepper or servo motor, whereas the lifting axis can employ a Festo DNCE electric or DNC pneumatic cylinder, depending on the user's performance requirements and technology preferences. A typical low-cost configuration would comprise a stepper-driven rotary axis and a standard DNC pneumatic cylinder to provide simple high accuracy linear movement between two positions. A more demanding application, requiring freely programmable linear positioning, could use suitable Festo servo motors and controllers for both axes – the linear axis being driven by a DNCE electric cylinder. This all-electric approach facilitates implementation of complex rotary/linear movement, with the significant advantage that machine productivity improvement, and even retooling, can be accomplished under software control alone.