Newbie- Laser power for cardboard cutting

[lucareds7]

Hello to all, I'm new in this forum but I'm not a newbie in mechanical engineering. I work in a firm where we design automation machines, and we received some enquiries about hte possibility of making a router for cutting corrugated cardboard with a laser beam.

Obviously we said yes, it's clear that this could be done, but laser is a new product for us, we don't know this technology.
Yes, we know that is a coherent beam of light, we know this could be generated from LED or tube, and the other common things that almost everyone know about it, but our questions are:

- is laser capable to cut five layer of paper (corrugated cardboard with double wave layer)? it's about 1/4" thick, but paper is only 50 mils, the other is air (trapped)

- does it require a large amount of power?

- is there any supplier that sell unit suitable for this application?

i did some searches on google, but I didn't found anything that could be suitable for this application at a reasonable price. We imagine that a unit for doing this operation shall cost about $500-1000 but it's only an idea.

Could someone please help us?

Many thanks & my best regards

Luca

[Litografa]

1) Equipment will not fit your budget and if you want design and sell it - be ready for numbers like 10 000 USD
2) You can cut only one layer during cycle
3) For corrugated board air assist with nytrogen is must

[bpoulin]

What size parts do you need to cut? How many do you need to cut? It may be in your best interest to outsource the project if you only need a few thousand pieces or less, because you're going to need to invest at minimum $6-8k plus the nitrogen system. You'll need the nitrogen to prevent the cardboard from igniting.

[fullspeceng]

We've cut 1/4" foam core and 1/4" cardboard using regular air assist with no flame up on our 40w lasers which cost around $2000 and have USA software and electronics that allow you to cut from any application: Full Spectrum Engineering

For a detailed paper cut with no burning, see here: http://www.fullspectrumengineering.c...=148&mode=view

[lucareds7]

thank you to all...

our goal is not the cheapest machine, but something different from what is already available on the market

a device up to 5k $ is already a good item for our goals, it make the machine a bit expensive, but we're not minding to propose an entry level...

@litografa: one layer of cardboard or one ply of the carboard itself? one ply should be around 4 mils (0,1 mm)...

@fullspeceng: do you sell even the laser tube and its generator? we are designing a completely different layout than a traditional router, so this is the aim that let us to interest to laser applications.

For data... our idea is to cut at a speed not less to i feet per second (300 mm/s) and five to nine layer of paper (corrugated cardboard with four wave layer is made of nine ply, thickness about 3/8" - 10 mm)

With this new data, received today from a potential customer, I think that power have to be raised up almost twice...

Air assist for us is not a problem, I even think that a good focused laser and an excess of pressurized air will do a good job. Like blowing on a candle, fire would estingish, or not?

[Rodney Gold]

The flutes in the corrugated carboard duct away the air assist and actually will promote flaming Be aware, you will get a charred edge on the cut whatever laser you use anyway.
The thickness of multilayer board will be an issue as the beam of the laser is focussed and it diverges away from the focal point. There is just a relatively small amount over and below the focus point where power density is ok for cutting , using longer focal length lenses will help , but will have an enlarged spot size. 10mm in carboard/paper consisting of multilayers will not be an easy task , the cut sides might have a curve as well , that follows the beam shape , thick stuff might cut like this )( and not like this ||. You would need quite a bit of power to have enough power density to cut properly. The cheaper glass tubes actually are worse as their spot sizes are large , a 75w RF co2 tube from synrad or coherent would be better, the beam quality is better. Maybe try a Reci glass tube?
I would imagine a reciprocating knife or some other system would be better than a laser for this application due to thickness

[lucareds7]

Originally Posted by Rodney Gold The flutes in the corrugated carboard duct away the air assist and actually will promote flaming Be aware, you will get a charred edge on the cut whatever laser you use anyway. The thickness of multilayer board will be an issue as the beam of the laser is focussed and it diverges away from the focal point. There is just a relatively small amount over and below the focus point where power density is ok for cutting , using longer focal length lenses will help , but will have an enlarged spot size. 10mm in carboard/paper consisting of multilayers will not be an easy task , the cut sides might have a curve as well , that follows the beam shape , thick stuff might cut like this )( and not like this ||. You would need quite a bit of power to have enough power density to cut properly. The cheaper glass tubes actually are worse as their spot sizes are large , a 75w RF co2 tube from synrad or coherent would be better, the beam quality is better. Maybe try a Reci glass tube? I would imagine a reciprocating knife or some other system would be better than a laser for this application due to thickness

Hi Rodney, first thank you!

charred edge won't be a problem, actually operations are performed mechanically but reciprocating forces are really big (it is something like a punching machine).
Laser would eliminate this problem, forces will be only ones due to dynamic of X&Y axis. This could make the machine lighter and consequently faster, because acceleration require less forces, and so X&Y drives could be lighter. On a 10 mm thickness I also thought that a long focus lens should be used to avoid )( effect, but to make it smaller i also thought to get a double lens, one short focus making beam narrower and one long focus to reduce the "hourglass" effect. This is a secondary problem, a couple of optical formulas and some practice on the field probably will solve it up.

The laughing thing... I found a firm that sells tubes & pover supply at five minutes from my home... does someone know them or their machines?

MTL - Home page

[bpoulin]

I don't know their quality first hand, but I can tell you by looking at their equipment that they are reselling Chinese equipment. Here's a link to an identical machine for almost $10k less.

[lucareds7]

Originally Posted by bpoulin I don't know their quality first hand, but I can tell you by looking at their equipment that they are reselling Chinese equipment. Here's a link to an identical machine for almost $10k less.

I supposed it... but consider that here in italy Vat, taxes and import duty have an heavy impact on reseller price...

When I buy item in USA, e.g., for a 100$ item I usually pay 25€, which is over 30%... and I buy used italian model engine! tried many times to make them think about it, probably I could more and more easily grow tomato plants on tarmac!

Other question... I see they write "steel reinforced belts" as it would be an improvement, we abandoned steel reinforced belts almost ten years ago... kevlar is not so expensive, is lighter, more flexible and won't suffer fatigue as steel do! I'm surprised that someone who build this "engineering jewels" employs steel belts, imagining this would be done only for the (extremely low) cheapness.

For all of you that is minding to design or build something with sincronous belts: use Kevlar reinforced, and use RPP profile! this combination reduce power loss and noise, parallely increasing its service life! +10% cost, -90% problems! Megadyne makes even Panther (XP) series, which is same kevlar reinforced but have a stiffeness bigger than the steel reinforced one!

(I changed from student to teacher........ wowwwwwwwwww!)

[bpoulin]

If you end up with a Chinese system, there are lots of little things like that you'll end up changing. For them it's all about the bottom line, cheapest product while not sacrificing the function. The steel belts don't effect the function of the machine, so by going with the cheap ones they save money. Grease is another one, they slop on a ton of cheap grease, I cleaned it all up, and put on a few drops of Teflon based machine oil and it runs a lot smoother.

[Rodney Gold]

Those prices are horrendous..even with import duties and freight

[lucareds7]

Originally Posted by Rodney Gold Those prices are horrendous..even with import duties and freight

I looked only to laser tubes and pwer supply, prices seems around ones seen around the net if added insured delivery and taxes... It's not as unusual as buying something at a reasonable price abroad, add transport, add vat, add taxes, add duties, add custom's charge and after checking all discover that you've spent around twice the initial costs... this is the thing that probably will let us choicing MTL as supplier... he's near us! if we need support & spares they're here!

And take care that the history is not ended... Buying abroad is a problem for an italian firm if done occasionally, even if we buy in EU countries... they're a lot of money and time to spend for burocracy! I thought this has be done to disencourage buying abroad, and parallely to make traditional import/export firm not to lose their clients... If you're a commercial firm the story is different, I know... but for technical/engineering in small/medium dimension of firm we're disencouraged buying abroad