The robot is used by an injection molder to hold and
transfer large, conical parts.
Get a Grip
Digital Mechanics AB, Västerås Sweden, combines its design and engineering experience with
rapid prototyping technology to tackle challenging projects. Often the work demands more than
a prototype. Recently, an injection-moulding customer asked Digital Mechanics to redesign a
robotic gripper. After evaluating the project, Digital Mechanics learned that it could produce the gripper via direct digital manufacturing.
The gripper is used to hold and transfer conical parts with diameters ranging from 15 to 19 inches (400 to 500 mm). Its vacuum hoses were causing problems in the automated factory and were the reason behind the design. “Robots were literally tripping over the gripper’s external hoses, slowing production and causing breakdowns,” says Digital Mechanics Managing Director Fredrik Finnberg.
To eliminate the vacuum hoses, Digital Mechanics designed gripper arms with
internal vacuum channels. However, this design would be costly to produce with
traditional machining. But the designers had another plan — to use the Fortus FDM
(fused deposition modeling) process for both prototyping and manufacturing of the
revised gripper. Because FDM is an additive fabrication process, it would be easy
to produce the internal vacuum channels. “We decided to test the [Fortus] machine
to manufacture the new parts, and we weren’t disappointed,” says Finnberg.
When this approach was proposed, the client agreed to test the design with FDM
parts. It also agreed that successful testing would give them the confidence to
use FDM for manufacturing of the production unit. Blurring the lines between
prototyping and manufacturing, the prototype would actually become the end
product if the design worked as planned.
Digital Mechanics used its Fortus machine to manufacture all of the rigid, plastic
parts for the gripper. “Direct digital manufacturing simplified the testing and
building process,” said Finnberg. “We were able to accomplish in days, from start
to finish, what would have taken months if we didn’t have the [Fortus] machine.”
The functional tests validated the hoseless design, demonstrating that the
channels provided sufficient vacuum to lift and transfer the conical parts. “We
knew from past projects that the [Fortus] machine was up to the job and would
result in an accurate, functioning unit,” says Finnberg. “The successful tests gave
our client the confidence to use the units in production. And the hoseless gripper
has now replaced the old model on the automated factory floor.”
“Our customer was happy with the results, and the gripper is now saving them
time, allowing them to produce more in the same time span,” Finnberg says.
“We’re already working with them to design a second generation gripper.”
Digital Mechanics has multiple prototyping systems in order to provide its
customers with the prototypes they need. Because the company is now able to
go beyond prototyping and move into direct digital manufacturing, the increased
work load has prompted them to purchase its third FDM system, which they
envision will perform an increasing amount of manufacturing work.
“Direct digital manufacturing has become a key revenue stream and competitive
differentiator for our business,” says Finnberg. “This would not be possible