Custom End-of-Arm Tooling Considerations For Packaging And Palletizing 
A wide variety of EOAT components are available
Written by John M. Westbeld, Engineering Manager, SAS Automation, LLC
Manufacturing Technology
June 2007

Robotic cells for material handling, packaging, and palletizing applications all have one thing in common; your robot is only as good as its End-of-Arm Tool (EOAT). EOAT can range from a simple vacuum cup tool to a tool with multiple actuators. The EOAT is application specific but this does not mean that the EOAT is always custom. A wide variety of standard modular EOAT components available on the market today make assembling your own EOAT very reasonable and cost justified. You can save thousands of dollars by buying components and building your own EOAT for the simpler applications. So how do you decide on whether to build your own EOAT or have a custom EOAT designed and built for you? The answer to this question is not always cut and dry and depends upon resources and skill level available.

Custom EOAT is needed for a variety reasons. The following are a few cases where custom EOAT may be needed:

• The product geometry does not lend itself to be secured by standard components.
• The environment or product characteristics contribute to special handling (oils, liquids, heat, texture, weight, etc.). 
• Several different sizes or configurations of product are required to be secured by the same EOAT. 
• Product spacing needs to be manipulated on the EOAT. 
• The equipment that interfaces with the EOAT / product has envelope constraints (fixtures, machines, etc.).

The more complex the product is and the more functionality you require on the EOAT the more likely you will need custom EOAT. As an example, say you have a packaging application where you are picking up bottles from a conveyor line and placing them into a case. To have the robot keep up with the line and to use only one robot you need the robot to pick up six bottles each cycle. The center-to-center spacing of the bottles needs to be reduced to fit the bottles inside of the case and to place them all at once. Custom EOAT can adjust the center-to-center spacing of the bottles while the robot is in route to the case. It becomes a simple pick and place application for the robot because there is more functionality on the EOAT.

There are a wide variety of pneumatic actuators that are typically used to add motion and functionality to gripping mechanisms on custom EOAT. These extra motions are used to secure, rotate, shuttle, and manipulate the product. External slides and bearing/rod assemblies are utilized frequently to make the EOAT more robust. Motors of various kinds can be incorporated as well to add actuation to the custom EOAT.

Application Example (Custom EOAT To Palletize Cases):

EOAT requirements

• Secure sealed cases with fragile product 
• Secure pallet 
• Palletize cases as close to each other as possible in one robotic sequence to maintain cycle time 
• Do not crush the product

This custom EOAT palletizes cases with fragile product (see photos 1&2). It secures the cases with independent mechanical grippers, which are assisted by vacuum cups. The mechanical grippers have a static side and a movable side. The static side is made of ¼” steel plates with a rubber insert to increase the friction coefficient. The profile of the static side was designed to be thin so the robot could place the cases as close as possible.

The movable side is actuated by pneumatic cylinders. The motion is controlled by bearings and rods. By having the grippers independent the robot could palletize the cases in various configurations. Vacuum cups were integrated into the movable side of the grippers so the pressure exerted on the cases could be reduced. This protected the case and the product.

Mechanical fingers were used to secure the pallets and place them into position for loading. Pallet sensors were utilized for accurately locating the pallets for pickup.

Vacuum systems can also be used for case palletizing. Typically vacuum cups are utilized with vacuum generators for each cup. This allows you to overcome the vacuum loss associated with corrugated cases. Special care must be taken to ensure particulate from the cases do not clog the vacuum generators. Vacuum pumps can also be incorporated to eliminate the compressed air needed. Large hoses will have to be maintained and accounted for in the robot path programming.

Custom EOAT is one way to get more out of your robot investment. They can increase the efficiencies and the functionality of your robot.

About SAS Automation

SAS is a leading supplier of modular EOAT components and robotic gripper systems – capable of servicing any part and any robot. SAS manufactures in the U.S. “get a grip!”, and distributes “nip it!” Nile sprue nipper line, and “GRIP IT!“ Asian chucking/gripper line. SAS is ISO 9001:2000 Quality Certified and specialists in robotic end-of-arm tooling & gripper systems, sprue nippers, CNC degating & Insert Mold tooling for manufacturing, packaging & plastics industries. 

Contact SAS Automation, LLC
1200 S. Patton St.
Xenia, OH 45385
Ph: 937-372-5255 
or visit www.sasgripper.com

Published by Manufacturing Technology