Wednesday, January 15, 2014

Picking the Right Robot

Denso Robot
Robots can be used to automate manufacturing lines of all sizes and volumes. The main goals of using robots are to accelerate cycle times, increase throughput, and eliminate bottlenecks on a line. Each type of robot has its pros and cons so selecting one is based on what works best in the application with regards to time and budget.

An evaluation must be done of the application. The main things to consider are load, orientation, speed, travel, precision, environment, duty cycle and programming.

1.   Load.  This can limit which robotic solutions are available right away. Consult the manufacturer’s specs to each robot to see if it something the robot can handle. Heavy payloads can deflect a robotic arm making it harder to consistently position the load with accuracy.
2.   Orientation. This depends on how the robot is mounted and how it situates parts or products that are being moved. Space within the work envelope must also be considered. The main goal of this is to match the robot’s footprint to the work area.
Codian Delta Robot
3.   Speed and Travel. Similar to load robot-manufacturers also list speed ratings. If the application being considered is pick and place, the amount of time during part transfer must be given heavy consideration. Cartesian robots will typically best fit in this application when distance is a factor because they can be customized externally by length and internally by using faster actuator components (belt, linear, ball screw, etc.).
4.   Precision. Delta, SCARA and six axis robots have a predefined accuracy rating making it easy to determine their repeatability of movement. Although this is ideal for some applications it can lock the user into one level of accuracy. A Cartesian robot once again can be customized if necessary for better precision. Also consider deflection. Heavy payloads = tougher success with precision.
5.   Environment. Three main things need to be considered: space available in work envelope, hazards and environmental situations. Overhead mounting is a good option in limited space or pick and place applications. For environmental issues many robots are available in an IP65 model.
ONEreach Cartesian Robot
6.   Duty Cycle. This depends on the user’s intent. A robot running 40 hours a week will have a longer lifespan than a robot running 24/7. Robots have varying maintenance schedules so finding one that limits downtime but has a long run life is essential.
7.   Programming. The most suitable robot for an application also depends on the requirements for controls and programmability. Typically the most basic controls are available with a Cartesian robot because of the simplicity of the design. Articulated, Delta and SCARA robots require more advanced functions which results in more time implementing them into action. Another thing to consider is communication with external additions such as an end effector, tool or vision system.

Robots are becoming a necessity in any automation application and can show an impressive ROI within weeks of implementation. For more information visit or contact one of our engineers to discuss your potential application.

Tim Pelesky
Marketing ONExia Inc