One of the most important stages to ensuring success for your robot deployment is selecting the right end of arm tooling (EOAT) for the job. Here we take a look at the steps needed in scoping out what tooling is required for your specific processes, parts and environment.
What is end of arm tooling?
First, it’s worth discussing some of the terms commonly used when referring to the physical interface between a robot and the item being moved or worked on. Depending on the organisation or sector, terms including end effector, gripper, robotic hand or manipulator are often used interchangeably. For consistency, here at Automata we tend to use “end of arm tooling” as the catch-all term and we’ll take a look at definitions for some of the other commonly used terms below.
Why is end of arm tooling required?
Different jobs require different tools. Even processes that might seem identical at first glance may require very different solutions because of differences in environment or the way parts are presented. Both industrial and collaborative robots are designed to be adopted by a broad range of industries and applications and as such are generally not supplied with specific end of arm tooling. It is therefore up to the organisation implementing the robot (or integrator doing the work on their behalf) to assess the job to be done and select the most appropriate tools for the tasks at hand.
Where to start: understand the problem you’re trying to solve
The variations of end of arm tooling are broad. Options range from off the shelf tools from vendors such as Schunk or Zimmer, custom solutions built by integration specialists such as Active8 Robots or custom-made in-house, taking advantage of an organisation’s internal tooling capabilities and/or widely available equipment such as 3D printing. We share some examples of end of arm tools below and you can view the options available directly through Automata on our Accessories page.
Before looking at the options available, it’s important to start with understanding the problem you’re trying to solve and what you want to achieve. Start by answering the following questions:
- What is the weight of the items the robot will be moving?
- What are the shapes and sizes of the items to be moved? Are they uniform?
- What kind of surfaces do the items have? Are they hard, soft, porous, dry, oiled?
- Are the items delicate, unstable or need to be handled with care?
- Will you need a binary motion (open and closed only), or flexible gripping strokes?
- Do you have cleanroom, temperature or hygiene related requirements?
- How will the parts be presented to the robot? Will they be uniformly presented?
- What motion or process does the robot need to carry out? (for example: pick and place, button push, hook or scoop, torque or tighten, dispense or weld)
- Do you have a single process or item to be moved, different items at different times, or multiple on the same line or cell?
- Do you need need to exert any force as part of the process (for example: twist, screw, button press, polish)
- What level of accuracy is required?
- Are any additional sensors required?
- Will humans be working alongside the robot?
Common end of arm tools
Once you have scoped out the specific requirements and challenges associated with the parts to be moved or manipulated, you can move on to selecting the right type of tooling for the job. Broadly there are four common categories of EOAT:
Pneumatic grippers are mechanical devices typically with two or three fingers, powered by compressed air that pushes the jaws open or closed. They are extremely common in manufacturing and are used for a whole range of pick and place type applications. These types of tool are typically less expensive than electric grippers; however, unlike electric grippers, a pneumatic gripper will require an air line or air compressor to function. Pneumatic grippers also tend to be less precise than electronic grippers. On the other hand, they provide a more compliant grip with respect to their electric counterpart, and they are more forgiving to variations in shape and size of target objects.
Electronic grippers, sometimes also known as servo grippers, are similar to pneumatic grippers but use electric actuation rather than compressed air to control the jaws of the tool. The benefit of this is they can be more precise than pneumatic grippers, with better control over speed, accuracy and force. The lack of need for compressed air can also mean a simpler set-up. However they tend to be heavier and more expensive than pneumatic grippers.
Vacuum grippers – end of arm tools that use suction cups, rather than jaws, to pick up and move items – are extremely common across the entire spectrum of manufacturing businesses. Best suited to workpieces that are non-porous, clean and have a uniform surface for the cup to attach to, they can be lighter and more affordable relative to pneumatic and electronic grippers and are highly customisable. They require a negative pressure supply, which is usually obtained by placing a venturi tube (which comes in the form of plastic inline connection) at the end of a compressed air line.
Electromagnetic grippers (and permanent magnet grippers) offer an alternative solution for ferrous metal parts. These types of tools are particularly useful for items that are not uniform and don’t have flat surfaces that might otherwise be challenging for grippers with jaws or suction cups. Particular care must be given to parts that might be sensitive to electromagnetic fields, such as delicate electronic components.
Specialist end of arm tools
In addition to these broad categories of end of arm tooling, there are also many types of custom and specialist solutions designed for specific applications such as spot glueing, welding, drilling, cutting, painting, spraying, buffing, scanning, sensing and vision.
Getting to success
If you’re installing the robot yourself, in addition to your chosen end of arm tool, you may also need to consider the following add-ons or accessories:
- An end plate (to attach the EOAT to the robot)
- Custom jaws or tooling (designed specifically to suit the workpiece)
- Cabling (to enable the robot to communicate with chosen tooling)
- An air supply (if using a pneumatic gripper or vacuum gripper)
- A vision system (if required for non-uniform parts or inspection)
- Additional safety requirements (if humans will be working with or near the robot)
To find out more about the common end of arm tools and accessories Automata’s customers use with Eva you can head over to our Accessories page. Alternatively you can speak to one of our experts by email, ask an expert or giving us a call directly on +44 020 3887 0254.