Because of the many options in the field of robotics, end users sometimes face a dilemma in choosing between entry-level and high-performance features. People have different perceptions of how to define performance, speed, power or expensive controls.
The best approach is to use a defined set of sizing and selection criteria to determine the required robotics feature set. This makes it possible to create a highly tailored robotic system that performs at exactly the right level and at the best possible price. The evaluation criteria include Load, Orientation, Speed, Travel, Precision, Environment and Duty cycle. We call this “LOSTPED.”
Advances in control technology allow operators to safely enter the machine cage to
“teach” the robot coordinates for picking and placing.
One common misconception is to think that you need to buy a robot fully equipped with high-performance features. That is inevitably the case with SCARA and six-axis robots, where you tend to see “feature overkill.” But with a Cartesian system, building blocks for a basic system can be purchased and then later customized. Mounting brackets, actuators, motors and control can be changed as application needs change.
There are pros and cons to this approach. The compact size of a SCARA robot might be more suitable for work inside a tight envelope. But if you have adequate space, a simpler Cartesian system can often be pre-built without having to purchase all the extra features included in a SCARA or six-axis design.
Moving from an entry-level to a high-performance feature set brings improvements in precision, cycle times and application capabilities. High-performance controls, for example, provide circular interpolation capabilities. That is a true high performance capability, requiring sophisticated and expensive control features. However, if the application only requires point-to-point motion (to pick up paper cups for example), that level of accuracy is not needed; a lower-level control can be used on the same robot to save money. High performance mechanical components in a machine tool may require the accuracy of precision-machined ball rail tables. They will cost more than a less-precise compact linear motion module that’s geared toward pick-and-place applications. A case-by-case LOSTPED evaluation will determine the best combination of performance and cost.
Adapted from an article written by Bosch Rexroth.
Bosch Rexroth Corp.
http://www.boschrexroth.com/en/us/
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