74: Rotary Fixture

Last weekend, I snuck a piece of hardware out of Eagle Engraving, Inc. while there was a lull in production. The hardware in question? A rotary fixture for our laser that allows us to engrave on cylindrical objects! I’d like to say they didn’t notice at all, but in reality they were totally cool with it and their resident laser ninja Monica even helped make sure that I had all the parts needed. Thanks again, Eagle!

The rotary fixture, slightly askew to account for the glassware's edge.

The rotary fixture, slightly askew to account for the glassware’s edge.

After installation and calibration, I first ran several tests on a piece of glassware that had sloping edges. Because the engraved surface of the material still has to remain parallel to the path of the laser carriage, I needed to use some shims to raise one side of the rotary fixture until the glassware’s surface lined up with the system.

Several engraving tests on one glass show off how images can be warped by bad diameter settings.

Several engraving tests on one glass show off how images can be warped by bad diameter settings.

The first several engravings helped me determine how important the diameter measurement of the glassware is.  Early on I was imprecise, which resulted in the round “Made in Aurora” logo used for the test appear as an oval.  3.0″ felt like a nice round number, but the glassware’s actual diameter at the center point where I wanted to engrave was actually 2.96″.  That kind of precision was required to prevent image distortion.

A close-up of the Planet Express glass.

A close-up of the Planet Express glass.

I used transfer paper to soften the engraving—several of my previous experiments with glassware showed that glass has a tendency to chip during engraving and create a harsher surface than necessary.  The transfer paper, while troublesome to remove, provided a filter that resulted in a smoother engraving, as visible in the difference between the Planet Express glass and the Shield glass.

A close-up of the Shield glass.

A close-up of the Shield glass.

The final piece we engraved was a red ceramic mug provided by Eagle for testing—it’s pictured in the featured image above, sporting a Hydra logo.  It was much easier to engrave thanks to a consistent diameter across the entire surface of the mug, unlike the glassware.

While Jennifer and I picked up a handful of cylindrical objects to engrave, we were only able to engrave cups and glassware due to an unforeseen lack of hardware: the rotary fixture includes one internal cone that holds the bottom surface of the cup and one external cone that fits inside the open top of said cup. You can use two internal cones to hold shapes that don’t have open tops (like the drum sticks I wanted to engrave!) but we didn’t have those handy.

Three round logos done right!

Three round logos done right!

While I’ve had to return the rotary fixture to Eagle since then, I do look forward to “stealing” it again in the future and, possibly, owning my own down the road.

 

 

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