Stringing Along a Grinding Application

(Excerpt from the Feature Article published in October's Today's Motor Vehicles)

Feeding an unbalanced valve seat component into a grinding machine created a challenge for Glebar.

An automotive powertrain supplier approached grinding machine manufacturer Glebar with two challenges in making the part – the need for 3,000 pieces per hour and figuring out a feed mechanism for the non-symmetrical component.

The two challenges are related. The high feed rate demanded to hit volume targets required an automated solution.

Hand placement or robotic pick-and-place systems would never be fast enough to get a part facing the grinding wheels every 1.2 seconds. However, the lopsided geometry of the parts meant that simply standing them on their sides to face the machine wouldn’t work, because the unbalanced parts would topple over.

“If you didn’t have a feature on the part, you could feed them back-to-back, and they would support each other going through the machine,” says Glebar President John Bannayan. “With the shoulder, we needed a different approach.”

Beaded necklace

Thankfully, the valve seat components were hollow, so Glebar engineers could develop a feed system that deposited the parts onto a wire. A vibratory bowl feeder sorts the parts so they drop onto the wire wide-side first (the bowl kicks parts back into the bowl if they try to enter the feed system narrow-side first). On the wire, parts align wide end to narrow end, creating a gap-free string of parts that feed into the grinder.

Imagine a beaded necklace – the parts line up on the string, creating a constant feed into the grinder without requiring direct manipulation of any workpiece. As the parts go through the machine, the grinding wheels finish them to a ±0.0002" tolerance.

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