End-of-Arm Tooling Works Together with Robots to Improve Process Flexibility
by Richard Petz and Tom Lakes of SAS Automation
Reprinted with permission from Robotics Online 

To be a success in today’s competitive market, a company must have an on-going cost improvement program.  One important aspect of reducing costs involves automation through the effective use of robots. ‘‘Effective use’‘ is the key phrase here.

Too many times major investments are made in robotic automation without the proper design and adaptability of an end effector.  This is precisely where end effectors, now more commonly named End-of-Arm Tools (EOAT), can improve both the flexibility and cost effectiveness by working with and complementing the robot. 

Specific questions need to be asked: What is the most cost effective method to assemble and to produce your product; what operation(s) can be eliminated; and what operation(s) can be combined to make a more cost effective operation?  To achieve maximum benefits, both manufacturing and assembly must be thoroughly analyzed.

When answering the above mentioned questions, engineering, purchasing and maintenance departments are looking to the flexible, lightweight EOAT for additional benefits as a priority. The shape, sizes, and weights of parts and the operations desired to be completed by the EOAT have increased tremendously.

Both the ease and flexibility which robots, versus people, can assemble or move a part is certainly the motivation behind the EOAT.  When the more difficult assembly is by people, more time is needed for assembly, defect rates increase and cycle times increase.  Manual assembly also requires ongoing training.

Smaller parts and shortened life cycles of the everyday items we use such as cell phones, hand-held tools, and office products are affected by rapid changes in technology.  Another trend is for automobiles to reduce weight to improve gas mileage and performance.  Now ask the same perpetual question about manufacturing and assembly of these components, and how can engineering clearly manage the automation cost effectively.  Answer: A compatible robot and EOAT.

There are many quality robot manufacturers to choose from.  Depending on the complexity and flexibility required, one has the choice of 2-axis, 3-axis or articulating motions.  Now, here is where the EOAT can make a difference.  In each process you are considering automating, include both the motions that can be obtained from a well-designed EOAT and the robot.  Research the features of each and determine the cost trade-offs.  For example, can a standard spring return gripper finger or small linear air cylinder on the EOAT reduce the need for an additional robot axis? 

To give manufacturers the ability to make quick changeovers, EOAT’s can be designed and built to accommodate this time savings.  The tool itself can be built on a lightweight frame with a quick-change system to allow an efficient change from one tool to another.   In other applications, adjustable EOAT components are essential to enable the manufacturer to use the same EOAT by using the components in a different configuration.

The use of adjustable, modular, light weight and quick-change EOAT features, combined with the advantages of using robots that are flexible in programming and functions, is saving the most dollars for manufacturers.  As an added dimension, systems are now available that allow the robot to pick up a tool at a designated area and install the EOAT automatically.

Short product life cycles, along with the need to reduce costs, have led engineers to look at all aspects of the process.  Robotic features and programming, along with the proper EOAT, was the obvious answer to help the robot to become more flexible.  In general, EOAT frames should be light weight and rigid, but the components need to be flexible. The flexibility is not in the components themselves, but in the functions they perform.  For example, a component designed and mounted on the EOAT to cut or trim a part could not flex during the operation, but the method by which it is attached to the frame would need to be quickly adjustable or flexible, to allow the same operation to be performed on a different part. The jaws of grippers designed and mounted to an EOAT would not necessarily need to flex during the assembly, but the advantage of repositioning the gripper at a different angle or position makes the tool more adaptable and cost-effective.

The robot and EOAT are increasingly required to perform multiple tasks, with multiple parts, simultaneously and/or progressively.  The EOAT depends on the robot to give the correct signal, have sufficient outputs and axis to perform the required task(s). On the other hand, the robot depends on the EOAT to hold, stack, and any other task(s) the automation cell is asked to do.  A robot's ability to perform at peak performance truly comes down to its EOAT.

While many of the functions required of the EOAT are typical such as grasp the part, feed the part, move the part, align the part after moving it, mount the part into final position, perform final assembly, inspect, shuttle parts(s) to next station - the tools themselves, are not typical. Of course, this is due to the increasingly wide variety of parts that robots are now being asked to handle.  Remember, when specifying the EOAT, ensure they provide the best opportunity to reduce costs by selecting modular, durable and lightweight components.  You may also consider an EOAT supplier who will completely design and build a tool for a complex operation.

As you review and analyze your manufacturing and assembly operations, ask again ‘‘What is the most cost effective method to produce this product, what operation(s) can we eliminate, what operations can we combine, and how can we use manpower most effectively.’‘  Then determine how to use the automation team of a robot and flexible EOAT as the cost justifying solution.

Editor’s note: All pictures compliments of SAS Automation.