Automation Supplement

The Forgotten Hand: Making the Right Choice for Your End-of-Arm Tooling

Photos In This Story

Standard EOAT components.
Photo courtesy: SAS Automation




The newly introduced programmable EOAT from SAS Automation eliminates the need for multiple EOATs.
Photo courtesy: SAS Automation

A custom end-of-arm-tool on a Fanuc robot.
Photo courtesy: SAS Automation

RFID technology is used on Wittmann robots to identify end-of-arm-tooling and select the correct Teach program for fail-proof operation.
Photo courtesy: Wittmann Canada


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 facility.

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 are available.”

When assembling the part, ODG’s Charlton also says that the EOAT has to interface electronically with the molding machine and all the downstream equipment.

“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 tolerance.”

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.

Resource List

ODG Industries Inc. (Barrie, Ont.)
www.odgautomation.com; 705-727-9760

SAS Automation LLC (Xenia, Ohio)
www.sasgripper.com; 1-888-727-3628

Wittmann Canada Inc. (Richmond Hill, Ont.)
www.wittmann-canada.com; 905-887-5355

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