Alliance Plastics (Erie, PA) manufactures a wide range of plastic products, including handles, tube inserts, and caps, plugs, cable ties, wire management components and fasteners, for sale throughout the world.

Recently, the company implemented an automated assembly machine to insert and verify the presence of O-rings in its valve-cap assemblies.

The eight-station system, which was built by Automated Industrial Systems Inc. (Erie, PA), employs a cam-operated rotary index table and a bulk hopper and stainless steel vibratory feeder bowl to feed the caps. In addition to boosting throughput, the machine has reduced labor costs by eliminating the need for any kind of visual inspections.

In operation, the caps travel from the feeder bowl to the machine via a stainless-steel track, where a pick-and-place unit at the first processing station transfers them in pairs to a fixture on the dial.

To facilitate seating, a dual-head lubricating system from Unist Inc. (Grand Rapids, MI) sprays the O-rings with an oil mist at the second station. The O-rings move via gravity track from a second stainless-steel feeder to the third station where an internal transfer mandrel removes a single O-ring, rotates it 90 degrees downward and places it on the first cap. 

The fixture then indexes to the fourth station, where a second mandrel places an O-ring in cap number two. A mechanical probe at the next station verifies that the O-rings have been correctly installed. Any defective assemblies are removed to a bulk collector at station six. The system shuts down automatically if it logs a predetermined number of consecutive parts, to help cut down on scrap.

At station seven, the good parts are unloaded into a bulk collector, and the fixture advances to station eight where a machine-vision system confirms that the fixture is empty before it is reloaded with parts at station one.

For more on automated O-ring and seal insertion call 814-838-2270 or

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