Cutting 1mm sterling silver sheets.

[Jacob John]

So I didn't want this to be part of the other thread, and wanted this to be a separate discussion. What would be the recommended type of machine to accomplish cutting 1mm sterling silver sheets as efficiently as possible?

Would a high wattage gantry style fiber be the best?

[Michael Henriksen]

You need something like a 500W IPG og nLight source as a minimum. 700W would be better. Price from USD40,000 and upwards based on recent quotes I have received.

[Jacob John]

You need something like a 500W IPG og nLight source as a minimum. 700W would be better. Price from USD40,000 and upwards based on recent quotes I have received.


Could you link me to one like it? 500 is what I told the person asking, but I wasn't 100% sure. Are these the oxygen fed ones?

[Michael Henriksen]

I've been looking at the LF1390 from G. Weike.

http://www.gwklaser.com/fiberlaser/LF1390.html

The LF1325 open flatbed is about the same price with a IPG or nLight source. Several vendors have told me the Raycus source is not good with reflective materials like silver and brass. IIRC you use nitrogen with silver but as the mfg.

[Jacob John]

Nice. At what wattage do you end up jumping into nitrogen and oxygen fed machines?

[Jacob John]

I've been looking at the LF1390 from G. Weike.

http://www.gwklaser.com/fiberlaser/LF1390.html

The LF1325 open flatbed is about the same price with a IPG or nLight source. Several vendors have told me the Raycus source is not good with reflective materials like silver and brass. IIRC you use nitrogen with silver but as the mfg.

I forget, is G Weike strictly Chinese? That machine is awesome, but can we find a comparable Chinese with US support?

[Michael Henriksen]

Check if Boss import fiber lasers. All cutters use gas assist, oxygen for mild steel, nitrogen for stainless, brass etc.

[Jacob John]

Check if Boss import fiber lasers. All cutters use gas assist, oxygen for mild steel, nitrogen for stainless, brass etc.

Will do. The one that was recommended to her was a 150 watt. She's cutting 1mm silver sheets and I'm not quite sure that's enough.

[Jacob John]

Here's a BOSS version though it looks more industrial. She'd rather an enclosed that can go in a garage style setup.

https://www.bosslaser.com/boss-fc-6012.html


https://youtu.be/vL57JVkTo4A

[Michael Henriksen]

I doubt 150W will cut anything other than mild steel.

Remember that if you want a machine with US support, the pricetag is likely to be double what you pay from the mfg. in China.

[Dave Sheldrake]

Oxygen on silver isn't going to end well. CO2 does NOT like silver, even at multi kilowatt ranges

[Dave Sheldrake]

Here's a BOSS version though it looks more industrial. She'd rather an enclosed that can go in a garage style setup.

https://www.bosslaser.com/boss-fc-6012.html


https://youtu.be/vL57JVkTo4A

thats an oxygen assisted CO2, if you want to cut silver reliably you need 750 - 1,000 watt fibres, 2,000 watts would be better.A 150 watt CO2 is going to make a real mess of silver and the machine doing it

[Jacob John]

thats an oxygen assisted CO2, if you want to cut silver reliably you need 750 - 1,000 watt fibres, 2,000 watts would be better.A 150 watt CO2 is going to make a real mess of silver and the machine doing it


Are you sure? They list it as a fiber flatbed available in 150 and 500 watt choices (BOSS FC 6012). Could you link a few that you would recommend? Does the fact that it's sterling silver matter? Sterling I know is silver/copper, so I'm not sure.

[Scott Shepherd]

Are you sure? They list it as a fiber flatbed available in 150 and 500 watt choices (BOSS FC 6012). Could you link a few that you would recommend?

Two things I know. 1) No one on this forum knows more about lasers than Dave. If he says it is dangerous, it’s dangerous. 2) I was part of a small group of people who had Boss lasers fiber laser shut down at a Vegas trade show. They were cutting stainless with a fiber laser, no guards, no eye protection for a laser running where people stood and watched machines run at a show. 1064nm fiber laser. Myself and two other manufacturers had to go to management of the show to have them shut down. When we politely asked them to stop before they damaged some innocent people’s eyes, they looked at us and said they had been given permission to run it.

If that’s the knowledge and behavior of someone selling fiber lasers for a living, I’d say you need to pick a more knowledable supplier. Just my personal opinion.

[Jacob John]

Two things I know. 1) No one on this forum knows more about lasers than Dave. If he says it is dangerous, it’s dangerous.

I was questioning him stating that it's a CO2 because their link states that it's a fiber. Definitely not questioning his experience. ;)



2) I was part of a small group of people who had Boss lasers fiber laser shut down at a Vegas trade show. They were cutting stainless with a fiber laser, no guards, no eye protection for a laser running where people stood and watched machines run at a show. 1064nm fiber laser. Myself and two other manufacturers had to go to management of the show to have them shut down. When we politely asked them to stop before they damaged some innocent people’s eyes, they looked at us and said they had been given permission to run it.

That's pretty crazy and good to know. It's also why I'm asking for recommendations. CO2's are within my knowledge base, and I'm learning about fibers, but these types of machines are way outside of anything I've ever seen.


If that’s the knowledge and behavior of someone selling fiber lasers for a living, I’d say you need to pick a more knowledable supplier. Just my personal opinion.

Again, why I am asking. :rolleyes: Appreciate your comments.

[Michael Henriksen]

The video is of a CO2 laser with oxygen assist judging by the look of the cuttig head, not the fiber they list. I also second what Dave says about power. I have been recommended a minimum of 700W fiber to cut silver. I just checked the quote and it does list nitrogen as assist gas for silver.

[Scott Shepherd]

I was questioning him stating that it's a CO2 because their link states that it's a fiber. Definitely not questioning his experience. ;)


Dave has been very vocal about Chinese lasers using Oxygen assist. He will correct me, for certain, but they seem to skip some very important safety measures, which makes them a bomb waiting to happen. I recall him posting photos of a laser accident (if I remember correctly) and it wiped out a brick building and killed people. Just because the Chinese can do it and show a video of it working, doesn't mean it's safe. I'd tread very carefully into such a machine.

I'm sure Dave can expand on the dangers.

[Dave Sheldrake]

Thanks for the kind words Scotty, I'm still very much learning as well.

CO2's wavelength see's silver like a mirror, once the Silver starts to melt it forms a highly reflective melt pool, that pool is in effect a liquid mirror.So scatter becomes a problem right away. Added to this the 10,640 wavelength of the CO2 beam isn't absorbed by the material very well at all (under 5% of the beam is actually *taken in* by the silver so for every 100 watts you fire at it, only around 5 watts are making it through.

Oxy assisted CO2's aren't really cutting by use of laser beam, what happens is the tiny melt pool forms on the steel and the oxygen introduction causes a fast exothermic reaction oxidising the metal, that's what's actually doing the cutting.

Fibre with it's 1,064 wavelength is not reflected by silver at any where near the magnitude that CO2 is so more of the *beam* is getting through, this allows the beam to break the molecular bonds of the metal allowing it to be cut (a photochemical action and not a photothermal , bandgaps etc) the Nitrogen is used to prevent oxidation of the surrounding area and the melt pool oxidising as well as a *pusher* to force the *liquid* metal through and out of the way
I don't know much about precious metals however if sterling contains copper then you have a second two fold problem,

Copper makes VERY good mirrors, so much so industrial CO2's use it for mirrors so that's going to be a problem, secondly copper is an exceptional conductor of heat, as you are trying to gain heat in the cut the copper will be doing it's best to conduct it away from the cut so efficiency drops again.

Cut quality with low powered CO2's + Oxygen isn't great, it works and is accurate but the underside has very much the same finish as a plasma cutter with dross and scag being a bit of a problem, it will rarely if ever produce finished quality parts that don't require a bit more work like de-scag or dross removal (tumble polishing)
Oxycuts are also always discoloured unlike nitrogen that cuts with a clean shiny edge

If I was looking to cut silver @ 1mm I'd be aiming at 1kw Fibre and better still more likely 2 - 2.5kw to get decent speed and efficiency

[Dave Sheldrake]

Just saw Scotty's comment about safety

Very much so, untested and uncertified Chinese metal cutters that use Oxygen are bombs

Oxygen is not flammable but it will make things that are normally not flammable into very flammable things. The gas lines on Chinese Oxy's tend to be Chinese quality, they aren't tested to UK standards and in the wrong circumstances can become "fuel" rather efficiently. They don't have tested "Intrinsic electrical safety" on lasers that use oxygen not only are all the supply routes of the oxygen strictly tested also the escape route of unused oxygen is controlled, you don't want a machine bed filling with unused oxygen gas if there is any signs of mineral oil or spontaneous combustion can become a big problem very quickly.

A self fuelling oxygen fire is as bad as it gets, it burns HOT ...VERY and the fire fighting methods of putting it out are very different...as Scotty mentioned, I did a consultancy job in India on an oxygen based explosion in a laser...it literally looked like a JDAM hit the building, one of the fatalities was still there when I arrived, they were busy trying to wash him off the wall with a fire hose :(

If you did want an oxy supported laser you can get them from the US and the UK that have been modified to meet the strict safety standards required for these kind of machines, in general though they are not the kind of machine I would counsel for a new laser user, they are simply too dangerous if you make a mistake and the results of those mistakes are very often fatal

[Dave Sheldrake]

The easiest way I can put it?

Apollo One, that was an oxygen fuelled fire

[Jacob John]

To bump my own thread, I'm looking at this machine, but it comes with a hefty pricetag.

https://www.laserstar.net/products/laser-cutting-system/

Anyone know of something similar and less expensive? Gantry fiber, compact desktop if possible. They state using an air assist instead of oxygen/nitrogen is possible. I'm really not comfortable using oxygen considering Dave's comments.

[Jacob John]

Forgot to add, I looked at waterjets, which are awesome, but I'm worried about both the cost of consumables (garnet), maintenance, and kerf considering I want intricate designs. Plus, any idea on cutting speeds with a 30,000psi system? I'd love to hear some waterjet opinions in addition to the above posts on a desktop fiber.

[Kev Williams]

That LaserStar machine, for the hefty price (I'm guessing north of 45?) would have to be kept pretty busy to pay for itself and still leave a little left over for the operator! And for that money, would an autofocusing stepper driven table be too much to ask? ;)

[Jacob John]

Think nearly 2/3 more. :eek:

So now I'm considering:

- Waterjet
- Plasma
- Kern CO2 cutter - And man I love their machines but I'm afraid of the risk of using Oxygen to cut. My machines are in my garage, and I'm afraid of fire or worse.

Any thoughts? It needs to cut intricate designs so a waterjet, I'm not sure can cut to the kerf for some pieces though maybe a desktop microjet exists somewhere.

[Brian Lamb]

Yes, small water jet machines exist, about $20k and will do up to 12" x 12". Made by Omax, who make larger industrial sized machines

https://protomax.com/?utm_source=easy-to-use&keyword_session_id=vt~adwords%7Ckt~desktop%20water jet%7Cmt~p%7Cta~224516056524&_vsrefdom=wordstream&gclid=EAIaIQobChMI_rfPxZS43QIVBP5kCh1oXQJ5EAAYASAA EgJL__D_BwE

[Kev Williams]

a little browsing found me this webpage - https://waterjets.org/archive/getting-the-most/tips/measuring-kerf-and-tool-offset/

-they note it's old material but contained some possibly helpful info, an excerpt:

Kerf” is a machining term that refers to the material removed during cutting... For example, if you cut a board with a saw, part of the board is turned into sawdust. If you put the two pieces of the board back together, you would find that they are slightly shorter than they were before, because some of that material (about the width of the saw blade) had been removed during cutting. The same effect applies with a waterjet machine: part of the material is removed during cutting. Of course, with a waterjet, the amount of material removed is much less than with a saw blade.

Typically, the waterjet kerf will be about 0.020″ to 0.060″ (0.5 mm to 1.5 mm), depending on the nozzle and the horsepower of the pump. There are some specialty nozzles that have a very small kerf on the low end of this range and are useful for cutting jewelry where the material is expensive and fine detail is required. Most systems have kerf widths ranging from 0.030″ to 0.040″ (0.76 mm to 1.0 mm).


A waterjet won't blow your home to bits, and it seems you might be able to find some nozzles that may work.. :)

[Jacob John]

Thanks Brian and Kev! Omax is who I'm actually getting to run some test cuts for me early next week. They tell me that the kerf is .03" (.76mm).

You think that small enough for intricate designs? They're confident that it will be.

[Jacob John]

I forgot to add, the next question will be how much Garnet will I consume when cutting these pieces? Since that's a consumable, it will obviously add to the cost of producing a piece, but is it minimal enough to where I won't have to worry about it as far as pricing is concerned.

[Brian Lamb]

I think .030" kerf, which amounts to a .015" corner radius is going to be plenty acceptable. I also suspect that with the thin material you want to cut, that might be able to be customized down even smaller. As for the consumption of the garnet, not sure that's going to be a big cost, first, it's usually not that expensive (at least not in blasting media) and from the pictures of the Omax unit, they appear to have an abrasive cup that isn't very large looking. I'm sure they can do a test cut and give you a breakdown of operating costs, garnet, electricity, does it use normal water or de-ionized? All of that should be something the sale man can get you info on.

[Jacob John]

I think .030" kerf, which amounts to a .015" corner radius is going to be plenty acceptable. I also suspect that with the thin material you want to cut, that might be able to be customized down even smaller. As for the consumption of the garnet, not sure that's going to be a big cost, first, it's usually not that expensive (at least not in blasting media) and from the pictures of the Omax unit, they appear to have an abrasive cup that isn't very large looking. I'm sure they can do a test cut and give you a breakdown of operating costs, garnet, electricity, does it use normal water or de-ionized? All of that should be something the sale man can get you info on.


Thanks Man! I'm getting more optimistic about this being a solution. I love my lasers, but for cutting, well, it just isn't cutting it. I wish there was a way to calculate the length of my pieces in EZCad because these waterjets have a speed in inches per minute. I could probably ballpark the cut time if I had that info, though it seems to cut a lot faster than my 50 watt. A small piece of copper on my 50 watt is about 12-18 minutes depending on size. That same piece in sterling is about 8 minutes. I think the same piece would be about a minute on the waterjet, maybe less.

[Kev Williams]

I wish there was a way to calculate the length of my pieces in EZCad because these waterjets have a speed in inches per minute. I could probably ballpark the cut time if I had that info,
Just so happens my cheap Chinese LaserSoft program will do just that, and I'm guessing RDWorks and any other Chinese laser program WITH a cut simulator probably will too...

I typed in 'WHAT'S MY LINEAR CUT DISTANCE?' in 24pt Arial in Corel, imported to LaserSoft and entered it into the simulator; it came up with 754.58mm-
here's a screenshot of the simulator-
393252
Closeup of the upper left corner so you can actually read the 'work distance'..
393253

so the outlines of that lettering at 1/4" tall total almost 29-3/4" total length--

I'd be glad to run some patterns thru my simulator, I use Corelx4- or you might be able to download LaserCut or some other software that will work in demo mode...

[Brian Lamb]

Most CAD software has an "analyze" function or maybe "Properties" that will list perimeter, surface area and if the part is 3D it will tell you volume and can give weights based on the type of material. You should be able to get the perimeter pretty easily that way. If nothing else, dimension all the straight lines and add the numbers up, it should be pretty close.

[Jacob John]

Just so happens my cheap Chinese LaserSoft program will do just that, and I'm guessing RDWorks and any other Chinese laser program WITH a cut simulator probably will too...

I typed in 'WHAT'S MY LINEAR CUT DISTANCE?' in 24pt Arial in Corel, imported to LaserSoft and entered it into the simulator; it came up with 754.58mm-
here's a screenshot of the simulator-
393252
Closeup of the upper left corner so you can actually read the 'work distance'..
393253

so the outlines of that lettering at 1/4" tall total almost 29-3/4" total length--

I'd be glad to run some patterns thru my simulator, I use Corelx4- or you might be able to download LaserCut or some other software that will work in demo mode...

So Kev, I downloaded Lasercut, and imported the image, ran simulate and I come up with two sets of numbers. Total length and cut length. Pretty big differences in those numbers. I'm guessing I go with total length?

[Kev Williams]

NO, go with cut length, which is pure "laser on" distance-- TOTAL length includes "laser off" moves too! Just from home to work and back home can add LOTS of distance depending on where the actual work starts!

[Jacob John]

NO, go with cut length, which is pure "laser on" distance-- TOTAL length includes "laser off" moves too! Just from home to work and back home can add LOTS of distance depending on where the actual work starts!


Well I'm glad I asked! :D

So for this one piece, it's 286.3mm (11.27"). But now I can't really find any info on these waterjets inches per minute calculation. Good thing the company that's selling them is going to give me that. I should know soon enough if a waterjet can beat my 13 minutes cut time on the fiber!