TM SCARA fastens on

The latest project from the partnership of TM Robotics, Toshiba Machine and systems integrator Evershed Robotics has demonstrated the speed and accuracy that can be gained by using robotics in the metal fabrication process.

The three companies have developed a system that machines lockable fasteners for car panels. It comprises four twin drill heads arranged on either side of a TM SR-504HSP SCARA robot.

Evershed Robotics designed the system so that one to four drills to be employed in a series, according to throughput requirements. At full output, the machine is capable of producing a finished fastener every four seconds.

The robot can handle up to 15 different fastener types, measuring between 9.5mm and 50mm in length. The fasteners are introduced to the drilling area from a vibratory feed bowl, via an escapement mechanism that presents them in approximate orientation. Working in conjunction with a recognition system, the TM SCARA robot picks the fastener up and then performs extremely fast, accurate, correctly orientated placements to any one of the free drill heads. Once the fasteners have been machined, they are automatically ejected into the output tray.

With its very high-speed 4-axis capability, the TM SCARA ideally suits such pick and place functions. The robotís SR7000 series controller gives it the ability to track and then pick an object from a moving conveyor, or receive input from a recognition device. It can then quickly transfer it to the target position with repeatability accuracy of ±0.02mm.

Toshiba's SCARA robots, distributed in the UK by TM Robotics, have arm reaches ranging between 424mm and 1054mm. Also in the SR series is the SR-654HSP, which has achieved record-breaking traversing rates of 600mm in 0.93 seconds, and even with a 5kg payload, the robot achieved the same distance in just 1.16 seconds. The reinforced arm can handle up to 20kg at half speed, or 10kg at full speed.

The SR700 robot controller is capable of simultaneously processing input and output signals during robot motion. Therefore no time is wasted waiting for signal processing to be completed. The controller uses absolute encoder feedback rather than incremental signals, thereby eliminating the need to implement a zero return on start up following a shut down.

There are options for PTP, short cut, linear interpolation and circular interpolation motion modes. With a total memory capacity of 6,400 points (12,800 steps), the controller also offers a multitask function, allowing a maximum of four tasks to be handled at any time. The mechanical movements of the SCARA robots are controlled using Toshiba's own revolutionary digital servomotors, amplifiers and motion controllers.