The Forgotten Hand: Making the Right Choice for Your End-of-Arm Tooling
Most discussions of automation solutions for plastics processors invariably
centre on innovations in robotics. The focus is not surprising: the actual
robot represents the biggest part of the investment when automating your
However, industry experts say processors should be giving equal consideration
to the end-of-arm tooling they will need to make effective use of their
new automation technology.
“You should really be thinking about it when you are buying your robot,”
noted Richard Petz, general manager at Xenia, Ohio-based SAS Automation.
In essence, Petz said, your new robot is only as good as the tool you
use. Processors looking to automate their facilities should be concurrently
thinking about the EOAT and the robot.
“Right up front, the end-of-arm tooling and the automation have both
got to be considered,” said ODG Industries Inc. president Rod Charlton.
“You can’t really source a robot until you know what an end-of-arm tool
has to look like. The payload and momentum [of the EOAT] is not known.”
Once the robot has been purchased, there is also the matter of assembling
a tool that effectively harnesses the robot’s capabilities. Is it best to
make your own tool, or is it better to have your EOAT custom-built? The
answer, industry leaders say, can depend on the complexity of your tool.
DOING IT YOURSELF
Simple end-of-arm tooling can often be designed and executed in-house,
if you have the time and skill to it. A less complex EOAT – which may consist
of a mounting plate and a small lightweight frame, with vacuum cups or pneumatic
gripping – can be built by someone with strong mechanical perception and
a good understanding of pneumatics.
“If the molding shops have in-house resources to build and even repair
their own molds, then design and application of their end-of-arm tools should
be well within their capabilities,” explained Charlton.
Simple tools are often defined by their application, such as removing
a part from the mold or grabbing the part and cutting the gate. However,
simple parts and applications don’t always call for less elaborate tooling.
“It’s kind of hard to say what the parts are [that are suited for simple
EOAT], because it really depends on how the mold is designed,” argued Christian
Weiss, technical sales, robots and automation, Wittmann Canada. If a mold
has been designed with the use of robots in mind, it is often easier and
simpler to automate the line.
When building your own EOAT, the first step is to source standard components,
preferably from a local supplier. For instance, robot manufacturer Wittmann
Canada makes a flexible end-of-arm tooling kit available to its customers,
based on the size aspect of the robot. The kits provide the processor with
all of the basic components needed to construct a simple EOAT.
SAS Automation’s Petz notes that parts should be purchased with the robot’s
capacities and the tooling’s applications in mind. “You want to make sure
that the product you buy are lightweight, very rigid, and durable for long
life,” he instructed.
Assemblers should also look for modular products that are easy to assemble
and adjust, Petz noted.
“The big thing about modular parts is, you can adjust them in three different
axis positions just by the loosening of a screw, and then sliding and tightening
them back up,” he said. “It saves companies money now that these products
When assembling the part, ODG’s Charlton also says that the EOAT has
to interface electronically with the molding machine and all the downstream
“Mechanically, it has to be able to absorb a lot of different variables
– the parts are in mechanical control, maintaining position, et cetera,”
he said. “Those two different processes, the automation side and the molding
side, have to talk to each other.”
Thus, it is important to collect information about the different machinery
and equipment such as: the robot’s maximum stroke, speeds, and payload restrictions;
molding machine’s dimensions, strokes, distances between tie bars, mold
open distances and clamp repeatabilities; mold data and detail prints; and
dimensions of the critical components and ejector strokes.
GOING THE CUSTOM BUILDING ROUTE
For more complex tooling applications, such as where the tool performs
multiple functions, processors fall back on the expertise of custom builders.
Charlton also noted that custom engineering is ideal for applications such
as in-mold labeling and insert molding, where repeatability and accuracy
is of the essence.
However, before embarking on a project with a custom engineer, Charlton
recommends that you check their references.
“Some people are in fact expects with EOATs and some people are experts
in automation, you need to have both if you are doing this type of project,”
said Charlton. “You also really want to make sure that the person who is
going to build the EOAT has a really good knowledge of the injection molding
process. If they have only dealt with steel, there is no shrinkage or repeatability
Processors looking for a custom turnkey solution now have a number of
resources available to them. For instance, in addition to its offering of
robotic solutions, Wittmann Canada also helps its clients build their EOAT.
“Knowing the design of the robot, we understand the robot options, what
the criteria are, the payload, et cetera,” said Weiss.
Custom engineering projects typically start with the collection of what
the processor wants to accomplish with their robot, and technical specifications
of all of the machinery and equipment. Wittmann, for instance, pays a visit
to the facility to have a look at the actual mold.
“Hopefully we can see there are no unique motions or rotations needed
or slides or anything when we see one of the molds running,” noted Weiss.
If the engineering project isn’t for an existing mold, Wittmann suggests
that the processor should start thinking of the EOAT and involve the automation
supplier at the mold design stage.
The custom solution provider may also ask for a few sample parts, basic
specifics about part spacing and core spaces, said Weiss. The custom engineering
firm then provides a drawing or simulation that fits the limitations of
your facility and makes efficient use of the robot’s capabilities.
Since custom tooling is their area of expertise, many of these companies
can build value-added features into your EOAT that improve efficiency and
enhance operations. For instance, Wittmann Canada has a state-of-the-art
radio frequency identification (RFID)-based recognition system supported
by their R7 robot control.
No knowledge is required during the tooling change in order to safely
change to the correct Teach sequence, and the ID also establishes link between
a specific gripper and the robot sequence.
SAS Automation also recently introduced the industry’s first programmable
EOAT to assist molders and manufacturers in cost reduction and efficiency.
This EOAT can be programmed to automatically relocate four separate component
holders within the cycle of the robot within the same EOAT, eliminating
the need for multiple end-of-arm tools. A robot can pick and place or pull
from an injection mold different sized items with just one EOAT.
ODG Industries Inc. (Barrie, Ont.)
SAS Automation LLC (Xenia, Ohio)
Wittmann Canada Inc. (Richmond Hill, Ont.)