Laser power ot cut layered aluminium/stainless foil

[asimpson]

I wish to cut metal foils of aluminium 0.05 mm and stainless steel 0.05 mm bonded with adhesive so that two metals dont come into contact or are welded together.

I am considering laser cutting.

How would I calculate power required and best type of laser?

How could I ensure two metals dont come into contact?

Many thanks.

 

[3DDave]

Waterjet cutting is more likely to work without problems.

 

[JNieman]

I would second the waterjet operation. The method of material removal for waterjet is much less likely to cause material contact and having the metal blow clean away. It is also much less finicky depending on laser maintenance, operator competence, and programmer knowledge. Less than ideal settings on a laser machine could see your parts ending up with fused edges at the cuts. From a purely risk-management approach, waterjet would seem to be the winner.

If you are 100% bound to laser cutting for any reason - I am sorry but my experience as a programmer and operator are limited and frankly far enough in the past that my memory is foggy. We use a waterjet where we are and have had good success. We have only cut differential metals WITHOUT the concern for metal-metal contact, though, so I have not examined that result closely enough to validate. That is a very interesting concern, though, which I believe I'd like to test soon.

_________________________________________
NX8.0, Solidworks 2014, AutoCAD, Enovia V5

 

[asimpson]

Thanks all.

I can see the advantages of water jetting however my concern is mounting the cutter head. I was hoping to put cutter head on small robot with a payload capacity of 3-kg. Are there feed pipes flexible to allow this?

these robots look prety big:

https://www.google.ie/search?tbm=is...=FizeVMrKCInuaLLZgUg&ved=0CAkQ9C8wAA#imgdii=_

 

[MikeHalloran]

If you can't keep a cutting machine busy at least 40 hours a week, it might make sense to engage a service instead.

Such services exist for both lasercut and waterjet technology, and will probably have a range of machines available, adapted for different performance criteria, e.g. precision vs. speed.

Best of all, you don't have to worry about machine sizing or maintenance; you just send a sheet of material and a DXF of the shapes you want.



Mike Halloran
Pembroke Pines, FL, USA

 

[3DDave]

The size of the robot it more dependent on the size of the part it is working on.

First work out the cutting process and then worry about putting it on a robot.

 

[berkshire]

The other part of this equaision is What is the OP talking about with the shape of the material. Is it a flat sheet that can be cut on a standard 3D table or is this a formed part that needs trimming In situ using more than 2axis
B.E.

You are judged not by what you know, but by what you can do.

 

[asimpson]

Thanks everyone

I'm working for a research compay and the way things are done don't often make economic sence. We have a robot and the idea was to make use of it rather than get a "proper" system. Not my idea may I add.

Really I need insight into the laser cutting proceess to see if it is feasible to cut a composite foil. Vendours I have talked with are compartmentalised and I cant get answers as to which type or method of laser cutting or even which questions to ask.

 

[BrianPetersen]

Research project suggests low-quantity job. It will almost certainly be less expensive to simply contract the job out to a waterjet-cutting shop than to fool around with that robot.

Keep in mind that any laser powerful enough to cut metal can only safely be operated inside a complete light-tight enclosure. Since a robot can point in any which direction, that has to be a full enclosure including the top, because you don't know which way the robot could be pointing. If it is a YAG laser, which is pretty likely at that power level, even the reflected laser radiation is extremely dangerous (and invisible). This ain't gonna be a cute little laser pointer that you are fiddling around with.

By the time you finish building that enclosure and having it inspected and certified, I've got the finished contracted-out parts in hand, and you haven't even started building your end-effector yet, or even thought about programming the robot.

 

[3DDave]

Are cutting lasers collimated? All the free-space optics I've seen have the source beam collimated in a lower power density beam with a simple lens at the end to focus the beam to operating intensity; this means that beyond the focal point the beam will continue to diverge rapidly. Probably it is still safer to enclose it, but the same is true of any high intensity lamp.

I need to look to see how the fiber lasers deal with the problem.

The OP needs to at least send samples to whoever he might buy the laser from to see if the material will cut as desired.

 

[BrianPetersen]

Yes, cutting lasers are focused. Yes, there is a LHZ (laser hazard zone) beyond which the intensity dissipates and is no longer considered hazardous. That does not mean you want to risk ANYone getting their eye in the path of the beam at any reasonable distance from the machine.

With a Class 4 laser (which this will be), both the direct exposure to the beam, AND the reflected laser radiation from the workpiece, are considered hazardous (up to the LHZ, which is a different calculation for each situation). With a little laser marker (used for engraving markings on parts) the power level is a few watts and the LHZ for the reflection isn't a large distance. With laser cutting or welding, that laser is likely a few kilowatts, and the LHZ for reflected laser radiation starts getting pretty significant. On top of that, the wavelength for YAG lasers is really nasty (and invisible).

I've dealt with a number of industrial robots performing laser cutting; they are all within light-tight enclosures that serve both as guarding for the robot motion and as protection against escape of laser light.

 

[3DDave]

I agree that good safety is a good idea. These guys are a little more lax

https://www.youtube.com/watch?v=leET8H_TH0o

I don't even see goggles in use. I like the idea of a safety sign - Wear Goggles to Protect Your Remaining Eye.

Also of interest was seeing that YAG sits near 1000nm and CO2 is near 10,000nm, making them perform very differently. The YAG has a higher absorption rate into metal than CO2, making it suitable for cutting and engraving of metals, but terrible for cutting wood and plastics relative to the CO2 lasers.

I'm still surprised by the original line of reasoning - They have foil and the have a robot and they settled on a some sort of laser because that's what they are pretty sure the robot can carry, without regard to whether the laser could trim the foil the way they want.

 

[gruntguru]

The requirement for avoiding contact between the two metals (electrical?) sounds difficult too.

je suis charlie

 

[moon161]

I contracted briefly at a manufacturer of cutting tables (laser, water, flame, plasma)and saw a 4kW gas laser go through setup and commissioning. It sure needed a big chiller. The 4kW was rated for I think 3/4" stainless or carbon steel, not rated for aluminum. Since, with any of the above processes, one metal will be blown past the other by a jet of gas, plasma or water & abrasive. If you really must avoid cross-contamination of materials, you might consider co-locating die cut or etched components of the different materials.

I've seen aluminum that was plasma cut. While it is doable, the kerf was on the order of the plate thickness, at least 3/8" or 1/2" for 1" plate. Compare to steel, where the kerf is about, IIRC .03" - .05". I think the water jet is preferred for Aluminum.

You might just shop the requirement around to different fabricators, machine or material shops and see what process(es) the suggest or quote.

In either case, it's more complex than putting a laser, torch or jet cutter on Wall-E. The controls guys there were smart and busy.

 

[asimpson]

Had discussion with some laser companies. To avoid heat transper to substrates a pico second pulse laser would probably be required . Cost of those goes well into the 5 figures.

I'll have to connsider further.

thanks