Small Component Precision Assembly with Scara Robot

A local company wanted to improve the production of filter assemblies for their specialized sensor products. They require an automated system that precisely assembles a combination of plastic lids, powder filters, and electrodes. Due to their size, the filter assemblies are difficult to manipulate by hand accurately and quickly.

The system will integrate into their existing workflow to allow operators to maximize upstream production, therefore the system would need to meet the following objectives:

• Be able to work with a variety of different components
• Easily add and change parts inside the system
• Verify accurate assembly of parts, and correct mistakes if possible
• Achieve a repeatable cycle time and higher throughput

After rigorous design and testing, Premier developed a standalone system that could be easily integrated into the customer’s facility. The final system arrangement was comprised of the following components:

• A Fanuc SCARA robot, with 650mm of reach and a 6kg payload
• An ATI tool change system
• The customer’s current assembly fixture is integrated into the system, to minimize changes in their current processes
• The customer’s current paper electrode fixture is integrated into the system, which allows for convenient refilling of material
• Multiple custom pneumatic tools to handle varying part sizes and makeups, including:
• Suction cup array for flat plate management
• Coanda-style vacuum gripper for lids with semi-porous surfaces
• Micro suction cup tool for lightweight filter materials
• Custom 3D-printed suction pads for non-symmetric paper electrodes
• Two Asyril vibratory feeding systems for bulk part feeding
• Each feeder is capable of separating and orientating parts for the robot to pick and place
• If parts are not pickable, the feeder will vibrate and shake the parts into a better position
• The feeders can automatically purge parts for easy changeover
• A custom Keyence vision system is used throughout the system for robot guidance and quality assurance
• Three cameras are used to locate component parts and guide the SCARA robot to the appropriate pick position
• One camera is used above the assembly fixture, and takes a picture of the fixture after each pick-and-place routine. If the assembly is missing a component, the system will automatically attempt to correct and replace it.

• The system can assemble a complete fixture of assemblies in 3 minutes, significantly faster than the current cycle time.
• In-process QA nearly eliminates missing components in the assembly
• The large capacity of the feeders and use of customer’s existing fixtures allows for easy changeover from one assembly to another
• With the use of a tool change system, the system can be outfitted for future assemblies and new components with minimal redesign.

Result

Premier was able to provide the customer with a fast and flexible system that improves production, strengthens quality, and allows for continued usefulness as their needs change.