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Darren Wilson
11-20-2015, 2:57 AM
Hello everyone,

Just wondering if there is any interest out there for a 8" FL lens for Epilog EXT engravers? They would be 19mm/.75" in dia. so they may fit other models as well.
I have made contact with a lens mfg in RI about there availability and was advised they would have to be custom made, with a min purchase of 40 units + tooling charge.
I am interested in such a lens to be able offer custom engraved "nucleated" beer glasses.
If there is anyone interested please PM for more details.

Hope this doesn't violate any forum rules

Thanks, Daz

Dave Sheldrake
11-20-2015, 5:24 AM
II-VI do 8 inch focal lengths off the shelf

the spot size will be huge though

Darren Wilson
11-20-2015, 5:56 AM
Hi Dave,

Off the shelf to suit Epilog? I wasn't aware of this, must have missed it on there web site/catalogue. Do you have a product code handy?
As far as spot size, I kind of guesstimated around .01", am I way off here? Would this not have enough power density to etch glass or make a clean enough mark?

Scott Shepherd
11-20-2015, 7:41 AM
Hi Dave,

Off the shelf to suit Epilog? I wasn't aware of this, must have missed it on there web site/catalogue. Do you have a product code handy?
As far as spot size, I kind of guesstimated around .01", am I way off here? Would this not have enough power density to etch glass or make a clean enough mark?

Yes, you are way off on the spot size. A 4" in larger than .01". It would probably be 1/16" or larger. Not to mention you won't be able to drop the table enough to focus it on most models.

Dan Hintz
11-20-2015, 7:59 AM
Yes, you are way off on the spot size. A 4" in larger than .01". It would probably be 1/16" or larger. Not to mention you won't be able to drop the table enough to focus it on most models.

I calculate about 18 mil focal point... you still have the issue of Z-height, however.

Keith Winter
11-20-2015, 2:45 PM
Your detail will be poor with a lens that big. Large spot size as others said.

Darren Wilson
11-20-2015, 5:14 PM
I have over 13" Z travel, so that isn't an issue. Dot size sounds like the problem. Lets take Dan's calculation as best case... 18mil (.018").... detail aside @75W would I still have enough power density to even mark glass? How about using beam expander prior to focusing to reduce dot size?

Probably what my post should have been was... "Has anyone engraved nucleated beer glasses?

David Somers
11-20-2015, 8:36 PM
Darren,

Pardon my ignorance. What will you be engraving this for? Are you engraving the outside of the glass for decoration? Or are you actually making the nucleation ring in the bottom of the glass?

If you are doing the ring, have you thought about just using a longer tube to hold the lens so you can reach deeply into the glass? Then you could use a focal length that suits the job better in terms of its dot size? You would need to restrict the movement of the laser head so you arent smashing into the sides of the glass of course. But otherwise, a long tube might do what you want rather than trying to shoot the beam that far?

Dave

Keith Winter
11-20-2015, 9:43 PM
Gonna be muddy and you are going to have a bunch of uncontrolled fracturing going on. Glass isn't forgiving and the spot size of an 8" lens is make the situation worse. Not sure on the beam expander. What are you trying to do with the glass exactly? That might help people to suggest better solutions.



I have over 13" Z travel, so that isn't an issue. Dot size sounds like the problem. Lets take Dan's calculation as best case... 18mil (.018").... detail aside @75W would I still have enough power density to even mark glass? How about using beam expander prior to focusing to reduce dot size?

Probably what my post should have been was... "Has anyone engraved nucleated beer glasses?

Dan Hintz
11-20-2015, 10:49 PM
I have over 13" Z travel, so that isn't an issue. Dot size sounds like the problem. Lets take Dan's calculation as best case... 18mil (.018").... detail aside @75W would I still have enough power density to even mark glass? How about using beam expander prior to focusing to reduce dot size?

Probably what my post should have been was... "Has anyone engraved nucleated beer glasses?

From a power density standpoint, you're at around 8% of a 2" lens. Settings would probably be somewhere in the range of 100P/25S, and I can't guarantee the glass would crack in a decent pattern, if it cracked at all without shattering the glass as a whole. Certainly worth a try, if the money is right, but I wouldn't get my hopes up.

Kev Williams
11-21-2015, 12:05 AM
a formula I found for spot size works like this:

.013 x lens focal length (in inches) / incident beam diameter at the lens (in mm) = spot size (in inches)...

Kind of hard for most of us to know what our incident beam diameter is, but seems 7mm is about average...?

So using 7mm as beam size for an 8" lens: .013 x 8 = .104, / 7mm = .01485" beam spot.

That's still a pretty fat spot size... I would think with a bit of vector testing, a loupe and a caliper mic, it wouldn't be hard to figure out how far out of focus to make a 2" lens run a .015" diameter spot. Then you could do some testing at least...

Darren Wilson
11-22-2015, 12:44 AM
Sorry, I should have explained better what I am trying to accomplish...

Nucleated glasses have a pattern etched into the bottom of the glass that causes the CO2 to get excited and keep a frothy head and releasing the aromas of the beer. Popular with boutique beers, Sierra Nevada has glasses mfg by Spiegelau.

They are available to purchase with a generic ring on bottom etc, but I wanted to try and make them with a custom logo as I have not seen this offered, I think this could be a good niche especially here in AU.

I like the idea of using a tube to drop lens in to glass, however this will only allow for one glass at a time which wouldn't be ideal. Ideally I wanted to set glasses in jig and engrave them in lots.

Darren Wilson
11-22-2015, 12:50 AM
Hi Kev,
So using this formula if beam diameter going in to lens is say doubled with beam expander to 14mm then spot size would drop to ~.0075" yes?

I may be way off here but I think that's what ULS do with their HPDFO – High Power Density Focusing Optics (HPDFO)


a formula I found for spot size works like this:

.013 x lens focal length (in inches) / incident beam diameter at the lens (in mm) = spot size (in inches)...

Kind of hard for most of us to know what our incident beam diameter is, but seems 7mm is about average...?

So using 7mm as beam size for an 8" lens: .013 x 8 = .104, / 7mm = .01485" beam spot.

That's still a pretty fat spot size... I would think with a bit of vector testing, a loupe and a caliper mic, it wouldn't be hard to figure out how far out of focus to make a 2" lens run a .015" diameter spot. Then you could do some testing at least...

Dave Sheldrake
11-22-2015, 7:07 AM
DOF = 2.5 x wavelength x ( f /D )2


If you play with the incidient beam diameter using a beam expander you can get pretty much anything you want

Kev Williams
11-22-2015, 11:59 AM
Spiegelau must make good glasses. The owner of the wine bar I engrave wine glasses for, which are Spiegelau, told me he and his partners searched for months for the perfect wine glass before they opened shop. He went into great detail about how the shape, size, thickness and other factors affected the taste of wine. It all went over my head :D -It's interesting to know they make a perfect beer glass too!

Depending on the logo detail, I think an 8" lens will probably work fine :)



.

Dan Hintz
11-22-2015, 2:05 PM
Spiegelau must make good glasses. The owner of the wine bar I engrave wine glasses for, which are Spiegelau, told me he and his partners searched for months for the perfect wine glass before they opened shop. He went into great detail about how the shape, size, thickness and other factors affected the taste of wine. It all went over my head :D -It's interesting to know they make a perfect beer glass too!

Every cruise we go on the sommelier drones on and on about similar things. In the end, giving the wine/beer the proper amount of aeration is all that's required, and the wide range of shapes/sizes could easily be chopped down to a small handful... but people like to feel (appear to others as?) sophisticated. I have champagne flutes, some highballs, some wine glasses, and some beer tumblers... that pretty much rounds out the majority of drink types.

David Somers
11-22-2015, 2:35 PM
Darren,

Kev Williams had a number of posts a ways back where he discussed his lens tubes that he uses on his Triumph. I dug and found it if it helps you. http://www.sawmillcreek.org/showthread.php?217673-My-new-lens-tubes-came&highlight=tube

Not sure how expensive an 8in lens would be for you so I dont know which is the better test for you.

My thoughts on speeding up handling on an extended tube setup would depend on how consistent the Spiegelau glasses are in terms of depth from the rim to the bottom.

If I can get some time I will try to draw up some thoughts I have on jigs that could speed up the handling of the glasses so that doing single glasses would not be too arduous. No guarantees though. We have company coming later today and have a ton to do before.

Fun project!

Dan.....I dont know about the beer glasses, but I have found the wine glasses certainly made a difference in taste. I was reallllllllly skeptical at first. Then one day a friend had me come over and without explaining what he was doing he blindfolded me and had me taste various wines and then describe how I liked them. I enjoy wine but am not educated about it at all and dont really care to spend the kind of time needed to become educated on it so my descriptions were pretty basic. When we were done it turned out that we had sampled 1 red wine and 1 white. Each one was sampled in 4 different glasses, one of each set of 4 was a Riedel, a competitor of Spiegelau. I thought I was sampling 4 different red wines and 4 different whites. And in each set I strongly favored the Riedel glass over the other 3 glasses. I was pretty stunned. I might add the wines he did this with were basically 2 buck chuck's from Trader Joe's. I was pretty amazed. Not enough that I was willing to pay that kind of money for a wine glass of course, at least not with my breakage record at home. But I was impressed with the perceived differences I experienced. I have no clue if the differences in beer glasses are the same, but I am more willing to be open about the idea after the 2 buck chuck test.

For whatever that is worth! <grin>

Dave

Ross Moshinsky
11-22-2015, 4:07 PM
My experience with glass/crystal is if the laser is out of focus, chipping starts occurring. So I can't imagine anything but a huge amount of chipping using a 8" focal length.

Scott Shepherd
11-22-2015, 4:36 PM
I think they do those with Galvo lasers. You get a really long focal length with those....


https://www.youtube.com/watch?v=BqJmH6hq3LM

Dave Sheldrake
11-22-2015, 4:40 PM
Every cruise we go on the sommelier drones on and on about similar things. In the end, giving the wine/beer the proper amount of aeration is all that's required, and the wide range of shapes/sizes could easily be chopped down to a small handful... but people like to feel (appear to others as?) sophisticated. I have champagne flutes, some highballs, some wine glasses, and some beer tumblers... that pretty much rounds out the majority of drink types.

hehehehehe I live in what was a restaurant...they left all the wine and glasses here when I got the place

funny part is I don't drink :)

Dave Sheldrake
11-22-2015, 4:41 PM
I think they do those with Galvo lasers. You get a really long focal length with those....


https://www.youtube.com/watch?v=BqJmH6hq3LM

long focal length Galvo for the win :)

David Somers
11-22-2015, 6:19 PM
A long focal length Galvo? That can be too awfully expensive huh Dave? Think that will be the next crowdfunded effort from GF? <grin>

Dave Sheldrake
11-22-2015, 6:52 PM
They all have pretty long focal lengths Dave compared to normal gantry machines :)

Scott Shepherd
11-22-2015, 7:05 PM
Chinese Galvos are cheap. I saw a fiber galvo recently, 30W (which is a lot for fiber) for $6,500. I would imagine CO2 galvo's would be less. The focal length on those things is about a foot or more.

David Somers
11-23-2015, 1:15 PM
Thanks Dave and Scott! I assumed those puppies were quite expensive for some reason! Good to know they are not bad in price. I am no where near needing one, but who knows! Thanks!!!! <grin>

Dave

Kev Williams
11-23-2015, 2:23 PM
taste sampling-- Not to throw water on your taste test Dave (I do believe the taste of wines can be altered) but I remember the very first time I ever watched Penn & Teller's Bull****, they were doing taste tests with patrons of a new restaurant, and they were testing "new brands" of bottled water. Each table of patrons that tested was brought a different bottle of water that was poured into a glass, along with an explanation of the water's "history". Without fail, every person found a difference in every water...

And every bottle will filled with a water hose out back behind the restaurant... :)

David Somers
11-23-2015, 6:15 PM
Kev,

He he he! Notice I have never bought the glasses? It was amazing though. My friend was suggesting he was testing anything. Just having me try different wines to see what I liked better. No description, just pour..."see how you like this one Dave!" sip sip. Repeat. It was interesting. And it was more of a "which wine do you like better" kind of thing rather than me trying to describe a wine. So it was pretty simple.

Darren Wilson
11-23-2015, 6:36 PM
Lots of great suggestions, thanks everyone for the input. I'll play around with focus on my 4" lens to try and get a spot comparable to 8" (.0175") to see what type of mark I can make and post results. Does look like the easy answer is a Galvo though!
To get the lenses made will incur a tooling fee of $1K plus I have to purchase 40 units @ $110USD, works out to $135USD each, so on my own don't think this will happen.
Cheers,
Daz

Scott Shepherd
11-23-2015, 6:50 PM
Try it with the 4" on a shot glass or highball glass. Then you'll prove the concept.

Darren Wilson
11-23-2015, 7:26 PM
Try it with the 4" on a shot glass or highball glass. Then you'll prove the concept.

You read my mind Scott:D

I Just picked up 72 of them to play around with.

David Somers
11-23-2015, 7:36 PM
Darren,

I finally got around to scratching out an idea for you. I was trying to come up with something that would not be too awfully labor intensive but would let you repeat the setup fairly quickly for each glass.
I stuck a scratched out drawing below. I havent had time to sit down and do something better looking on the computer so you get napkin scratching. Apologies!

My thought was that you use some mdf or whatever and make this jig. It rests on two rails that run front to back on your laser table, perhaps setting in the slots used for your knife edges. The key is that it is open beneath the rails. Pull your honeycomb table out.
The jig is attached to those rails. There is a base that can slide in an out easily on dados on either side of the jig. The fit should be loose so you can slide it very easily.
Pull the base out.
Slide a glass over the laser tube from below. Your 4" lens might be easier to work with but you could try with a 2" as well.
Slide it up over the tube, then slide the base into the dados and then let the glass rest on the base. The glass is now centered, and the inside bottom of the glass is at the focal point of the lens.
Do your engraving.
Slide the glass up and then remove the base.
Drop the glass down to clear the tube and slide a new glass up over the tube and put the base back into place.
Keep repeating this.

Not as nice as the video above of the Galvo with the powered conveyor belt!! <grin> But it wouldnt be too intensive to deal with in the interim till you can arrange for something better. It would also be a simple way to develop the concept without sinking lots of $$ into it.
I hope this gives you a good case of the giggles at the very least!!! <grin> And maybe the nucleus of an idea to play with.

Good luck with this! Sounds like a fun and interesting project for your business!!

Dave
325769

Darren Wilson
11-23-2015, 10:52 PM
Darren,

I finally got around to scratching out an idea for you. I was trying to come up with something that would not be too awfully labor intensive but would let you repeat the setup fairly quickly for each glass.
I stuck a scratched out drawing below. I havent had time to sit down and do something better looking on the computer so you get napkin scratching. Apologies!



My thought was that you use some mdf or whatever and make this jig. It rests on two rails that run front to back on your laser table, perhaps setting in the slots used for your knife edges. The key is that it is open beneath the rails. Pull your honeycomb table out.
The jig is attached to those rails. There is a base that can slide in an out easily on dados on either side of the jig. The fit should be loose so you can slide it very easily.
Pull the base out.
Slide a glass over the laser tube from below. Your 4" lens might be easier to work with but you could try with a 2" as well.
Slide it up over the tube, then slide the base into the dados and then let the glass rest on the base. The glass is now centered, and the inside bottom of the glass is at the focal point of the lens.
Do your engraving.
Slide the glass up and then remove the base.
Drop the glass down to clear the tube and slide a new glass up over the tube and put the base back into place.
Keep repeating this.

Not as nice as the video above of the Galvo with the powered conveyor belt!! <grin> But it wouldnt be too intensive to deal with in the interim till you can arrange for something better. It would also be a simple way to develop the concept without sinking lots of $$ into it.
I hope this gives you a good case of the giggles at the very least!!! <grin> And maybe the nucleus of an idea to play with.

Good luck with this! Sounds like a fun and interesting project for your business!!

Dave
325769
Hi David,
Wow, that's a great idea, no need for apologies, the sketch and explanation are perfect! Easily done too by the looks of it. Will definitely give this a crack!
Kind regards,
Daz

George M. Perzel
11-24-2015, 12:21 PM
Darren;
Stepping outside the box a bit, why not engrave flat glass discs and drop them in the bottom of the glass??
Best Regards,
George
Laserarts

Dan Hintz
11-25-2015, 3:26 PM
Darren;
Stepping outside the box a bit, why not engrave flat glass discs and drop them in the bottom of the glass??
Best Regards,
George
Laserarts

Need to be big enough to avoid being swallowed. Once big enough, have to be thick enough to avoid being broken. Insurance issues with people potentially swallowing broken glass. They'd have to be anchored to avoid slopping to the top of the glass as you finish one off.

I could think of others, I'm sure.