Engraving equally spaced marks on cylinder

[Larry Schneider]

I know the title is a little misleading but I couldn't come up with another.
I have a 60 watt Epilog with a rotary attachment. How do I engrave 19 equally spaced marks around the circumference of a part 0.062 diameter X 0.125 long. The rotary attachment uses friction to turn the part and that and the "slop" in the design of the attachment prevent being accurate. This is a very well paying reoccurring opportunity. I mean real well paying.

[Dan Hintz]

The Epilog rotary has a "hold down" attachment, but that only works if you can get inside the object (like a glass). If you need absolute accuracy without slipping, you'll need to consider converting the rotary to more of a chuck/cone system.

[Gary Hair]

This is a very well paying reoccurring opportunity. I mean real well paying.

If it's that well paying then it would be beneficial to buy a chuck style attachment instead of the hot-dog roller type.

[David Somers]

Larry,

I think I am being dense this morning. Too many conference calls.
But your question says the diameter of your cylinder is .062, as in 62/1000 and its length is .125? Inches? MM's? That all seems way smaller than the Epi rotary could handle, even modified? Or am I misinterpreting what you are asking?

[Kev Williams]

.062 x pi - .19", /19 spaces = marks at .010"- with a beam width of .005" you're looking at mark width and space width being equal. As I see it, you have around +/- 0.0005" tolerance. Maybe.

JMO but methinks you'll need a whole different machine.

If it's REAL well paying, it's worth looking into a machine capable of doing it.

(I'm facing the exact same issue at the moment, so I can relate)

[matthew knott]

Im with David on this, parts that size you simply wont be able to do with your current equipment, your part is on 1.6mm diameter, you want 19 marks, thats less than .1mm per division, you would need a laser with a focuesd spot size of about 0.05mm so your into a yag of fiber laser really. Also how long do the marks have to be as the part is only 3.175mm long, even with a 3 jaw chuck thats tricky, and if the marks need to be full length imposible. Also be a bit warry of "very well paying reoccurring opportunity. I mean real well paying." jobs that you need to invest lots of money into. Someone with a small rotary and fibre laser could probably do these in a few seconds each, one phone call to a competitor and the work could vanish as they wont pay 'real well' if they dont need too. For example the bits in the photo used to pay us really well but now we can only charge about $0.90 each as the game has changed

wp8cbc06c9_05_1a.jpgThese are about 3 times the size of your parts !!

[Gary Hair]

I assumed the dimensions he gave were of the mark, not the part. I can't imagine making 19 marks around a cylinder that is 1/16" diameter by 1/8" long! Perhaps the OP could give some clarification?

[Larry Schneider]

I admit I screw up. the parts are 0.62 or about 5/8" diameter, a circumference of 1.9 inches.. Yes the part need marked the entire length so it must be "held" from the id not the od. Obviously the rotary attachment that is available for the Helix isn't accurate enough and I'm under the impression that the Fibermark 3 jaw chuck attachment won't work with the Helix.

[Keith Upton]

What about securing them to a heavy rod before engraving them. The weight of the rod should keep it from slipping on the rotary attachment. If it needs more grip, could rough the rod up some.

[Gary Hair]

Is it a tube or a solid piece? If it's a tube then you could easily make a couple of cones to hold it, if solid then it might be a bit more challenging, especially since you need to mark the entire length. Is it ferrous? Maybe a magnet attached to a plate on both ends?

[Larry Schneider]

It's tubing and I thought about ganging them up on a 10 or 12" rod but my concern was accuracy with the standard what was it called, hotdog turner, rotary attachment. Or am I worrying about nothing?

[Keith Upton]

I've not noticed any slippage on my Epilog rotary attachment, but I've not done any precision marking either. I'm pretty sure if you use the rod method, you will not have any issues. Being that the rod is going to be pretty small, there is going to be a large contact patch between the rollers and the rod... which is a good thing.

If this is really going to be a long term, well paying client, it might be worth picking up a 2nd rotary attachment and modifying it. Just build a new bracket that moves on of the drive wheels and support wheels to dead center. Remove the wheels and mount the rod directly to the shaft/spline (not sure what it's called in laser terms). If you counter thread both ends, you can screw the rod in tight with your parts already load on it. No chance for slippage that way.

[Keith Upton]

Another thought just came to me.... Plasti-Dip the rod. I can't see it slipping at all then.

[Larry Schneider]

Some good ideas, Thanks! I could knurl the drive end also since I'll have it in a lathe to get the right diameter anyhow.
I appreciate all the input.

[Kev Williams]

I'm still confused on the actual size of the part-- we went from .062 to .62, which makes sense, but in the first post the LENGTH is stated to be .125" (1/8)"...?

And from experience-- beware of "long term well paying clients"... The whole reason I bought my LS900 was because my ULS couldn't keep up with a steady job I had. Every other day the place was bringing me 500 to 1500 more parts to engrave! And as soon as the LS900 showed up, THEY stopped showing up-- turns out their parts were being made by a machine shop in Mexico. And the machine shop wasn't paying THEIR suppliers, they just partied the money away. Suddenly, no more parts. My customer couldn't find replacements for less than 5x what they paid the Mexico shop. My new laser never engraved a single one of those parts!

But it's engraved a lot of other stuff since then!