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, also known as rapid prototyping.

Digital Mechanics’ task required the redesign and production of a robotic vacuum gripper. Used to hold and transfer conical parts with diameters ranging from 153/4 to 191/2inches (400 to 500mm), the gripper’s vacuum hoses were causing problems in the automated factory. “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’ design approach incorporated hollow gripper arms with internal vacuum channels. However, this design would be costly to produce driven by a more traditional CNC (computer numerical control) machine. But the designers had another plan – to use FDM (fused deposition modelling) for both the prototyping and manufacturing of the revised gripper. “We decided to test the Stratasys 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 FDM Vantage S machine to manufacture all of the rigid, plastic parts to 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 FDM machine.”

The functional tests validated the hoseless design, demonstrating that the vacuum channels provided the suction to hold the conical parts. “We knew from past projects that the Stratasys machine was up to the job and would result in an accurate, functioning unit,” says Finnberg. The tests also gave the client the confidence to use the units in production. Using direct digital manufacturing, the hoseless gripper has 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 customer 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 another FDM system, which they envision will perform an increasing amount of manufacturing work.

Stratasys is based Frankfurt am Main, Germany. www.stratasys.com