Galvo Laser

[Jiten Patel]

Hey folks,

a few people have requested a video of my machine at work, so here is a youtube post.

Sorry for the quality, shot from a phone!!! :eek:

http://www.youtube.com/watch?v=QkUvO9TuEM8

[David Fairfield]

Ah, now I see why you use one of these! Cool seeing the little flame jump around with no armature! You probably don't get the little tremors at the curves either, perfect for your scrollwork. Very interesting, thanks for posting!

Dave

[Chuck Stone]

wow .. I can see where air assist might be an issue..

[Jiten Patel]

David, the curves are smooth as they get as the beam comes from a fix point rather than a mechanical arm.

Love it, she is an amazing bit of kit.....just need MORE POWER so we can cut quicker.

We are getting a new lens soon which will hopefully double the speed (at a sacrafice of almost halving the working area from 280mm x280mm to 180mmx180mm)

[paul mott]

Hi Jit,

Difficult to see clearly from the video but you have got to get rid of those flames. Although impressive to watch (very impressive to watch) the end result is poor with blackened edges and surface in some places.
The shorter FD lens should reduce the spot size and increase power at the kerf which should improve matters but I am thinking that you probably need a lot more power and / or use an inert gas to suppress the flames before the quality improves.

My wife wanted to make those 3D decoupage things where the multiple images are usually die cut and on initial tests we were both disappointed with the sooty edges the laser produced. I haven't yet got around to cutting card in a Nitrogen environment but this is something for the future, as and when....

Paul.

[Jiten Patel]

Paul, you are right with regards to the flame. We do get soot on our edges which we clean off by hand. So when one is lasering, we clean the other one, which ends up being completely clean (check out our website for the finished article). We hardly ever get blackened surface. We couldnt sell our products if we did. No bride wants black soot covered invitations. Its usually 1 out of 100 invites that gets some sort of marking, and thats usually due to the honeycomb (tick marks).

Different card stocks react differently, some soot quite badly, and some not at all. We are getting a new lens in the next few weeks, so hopefully that will sort things out a little. We are only running at 50% power as running at 100% loses some of the detail. But hopefully with the new lens, we can run at 100% and much quicker, therefore losing the flame.

Can someone shed some like on the inert gases and how the set up work along with the costs involved. We run our laser 7-10 hours a day, constantly cutting our invitations/stationery. Crazy busy at the moment. So if we were to get a nitrogen set up, Im assuming we would have to be running nitrogen all the time?

[Dan Hintz]

Jiten,

Be aware that running gases with a galvo is not the same as with a carriage-type laser... with the carriage, you have a source of air within an inch or two of the substrate. With galvos, it's farther away, and since the cutting area is much larger compared to where the laser sits, you can't just point at a specific place and go. It would require surrounding the entire bed in inert gas flow.

[Rodne Gold]

You really need air assist and you could accomplish that by using multiple nozzles quite high up at all 4 sides of the cardstock directed strongly downwards to the cut area , you can use strong vaccum on the underside of the cardstock to keep it in place and stop small pieces flying out
The air assist nozzles if directed steeply down can also help hold the pieces in place.
Alternatively , you can look for an inert gas that is heavier than air and build an enclosure that would keep it all in , with a small orifice for the laser , and flood the cardstock with the gas , but you would have issues with smoke and vacuum

[Jiten Patel]

Dan,

So really and trully without spending a fortune on getting a custom setup, its not going to happen. Hopefully the new lens reduces it. The soot is annoying when working with lighter shades as hands get messy and transfer to the card.

[paul mott]

Paul, you are right with regards to the flame. We do get soot on our edges which we clean off by hand. So when one is lasering, we clean the other one, which ends up being completely clean (check out our website for the finished article). We hardly ever get blackened surface. We couldnt sell our products if we did. No bride wants black soot covered invitations. Its usually 1 out of 100 invites that gets some sort of marking, and thats usually due to the honeycomb (tick marks).

Different card stocks react differently, some soot quite badly, and some not at all. We are getting a new lens in the next few weeks, so hopefully that will sort things out a little. We are only running at 50% power as running at 100% loses some of the detail. But hopefully with the new lens, we can run at 100% and much quicker, therefore losing the flame.

Can someone shed some like on the inert gases and how the set up work along with the costs involved. We run our laser 7-10 hours a day, constantly cutting our invitations/stationery. Crazy busy at the moment. So if we were to get a nitrogen set up, Im assuming we would have to be running nitrogen all the time?

Hi Jit,

I have seen your website and your work is truly beautiful.
I was just commenting on the Galvo result you showed which does not appear to be as clean as you have achieved with conventional scan.
From the video it is difficult to tell but Is this true please ?

Paul.

[Jiten Patel]

not sure what you mean by conventional scan?

In the video, its a bit dark, but the card stock is fine. Charred yes, but once brushed off with a fine makeup brush, good as new and ready to send out (the video is an actual order that we were working on).

[paul mott]

Thanks.

Paul.

[Robert Walters]

Jit,

I know there's an acrylic box below the honeycomb to catch the swarf, but is there any airflow sucking the workpiece down too?

If not (or very little), you might be able to create a lip on the outside of the honeycomb are that is above the workpiece by a few inches, then fill the entire container (up to the lip you create) with nitrogen gas, or maybe just blow nitrogen across the workpiece from both sides to get full coverage. (Just random thoughts on my part, YMMV)

Sidenote... The zipline looks AWESOME, glad you didn't die!

[Jiten Patel]

Robert,

The dust collector is direcetly under the work piece so acts like a vaccum table. I have since recieved my new "jig" which as expected didnt work. Build with sliding rules for registration, but the card stock just slides underneath. I thought i would try magnets, but blond moment, forgot that honeycomb is aluminium! DUH!!!

Lol, zipline, thought no one would check that out. That was when my wife (girlfriend at the time) and I went on our round the world tour for 8 months. that was in Laos.

[Robert Walters]

Jit,

What if you placed thin self-adhesive foam weather stripping under the rulers?

Look for the kind that is used to seal camper shells to pickup truck bed,
It's very thin, high quality, and compresses well.




There's one zipline in South America somewhere that are interconnected. So you get into a harness, then across one zipline to a platform, unclip from zipline A, then clip into zipline B, etc all at the tree canopy level around the jungle.

[Jeff Belany]

Great video. Gives a lot of us something to drool over. Your creations are beautiful.

Just curious -- does your galvo have a vector sorting function similar to the conventional lasers? That really cuts down the 'jumping around' from area to area. At least it makes a noticable difference in times on my machine. On your complex cuts it should be very a big help.

Jeff in northern Wisconsin

[Dan Hintz]

Just curious -- does your galvo have a vector sorting function similar to the conventional lasers? That really cuts down the 'jumping around' from area to area. At least it makes a noticable difference in times on my machine. On your complex cuts it should be very a big help.
Galvos have a significantly reduced need for vector sorting as they do not have a slow-moving carriage to shuttle around and a reduced working area. It would, at best, reduce the time seen for that sheet by a second or two, and even then I would be skeptical.

[Jiten Patel]

Jeff,

The program itself doesnt have a sorting function. But if i order everything correctly in Illustrator then I get the galvo to following a certain path. Did it on one design (took me quite a few hours to get everything in order as my designs are fairly complicated) and it made as Dan said, a difference of a few seconds. Not really worth the time.

The jump speed between points it 10000-15000 mm/s so Im not too worried. Will post up a new video when I get my new 250mm lens, which will triple the speed. Can't wait to get it!

[paul mott]

Hi Jit,

I higher quality video would be nice to see, please.
When I saw your last one I thought you were burning the surface as this still clip seems to show. :(

Paul.

[Jiten Patel]

Hi Paul,

Yea that still does look like it's burnt doesnt it. It's just a thick layer of soot. When I brush it off, it all falls off leaving the card as it was. check out the pic of the finished product. i promise this is the exact same batch at the one in the video. The middle of that invitation is vector marked rather than cut.

I really do want to reduce the charring as cleaning is the bain of my life at the mo. When working with lighter card stocks, its easy to get dirty fingers which results in finger prints which result in rejects!

190704190703
http://www.sawmillcreek.org/images/misc/pencil.png

[Dan Hintz]

Jit,

I'll see nasty edges like that when I'm not in focus... are you positive that thing is focused properly? I would not be happy with those edges, pre- or post-cleaning.

[Jiten Patel]

Yea i thought the same thing. I was getting those edges since i got my new jig. I obviously haven’t got it at the right height. I will re-adjust tonight and try again. This laser lark is a hell of a lot harder than I first though. Thank you for the advice.

Edit: Just so you know Dan, the jig has to be raised and lowered manually, and its a glorified chair mechanism so it's incredibly hard to get it at the right height when being focus out 1mm causes edges like that.

[Dan Hintz]

It may be time to add a DRO (digital read-out) to your table, similar to what the woodworkers use on planers and such for getting the perfect height. It wouldn't make moving the table any easier, but it would let you know if you're at the proper focal point or not.

[Jiten Patel]

Thanks for that, I will look into one of those. Any idea on the cost?

[Dan Hintz]

If you hack one up from a Harbor Freight type set of calipers, $15-20... if you go for a true DRO (not necessary for what you're doing, mind you), probably closer to $75-100. You don't need accuracy, per se, just repeatability.

[Jiten Patel]

you my friend are a legend indeed. I will have a look see and pick one up. I can do £10-15 rather than £75!

[Jiten Patel]

how about one of these?

http://www.tradetools.co/route=product/product&product_id=18691

[Dan Hintz]

Definitely not.... those things have accuracies measured in the 1/4"-1/2" range. You need something along the lines of at least 1/10". Even cheap digital calipers will give you 1/100".

[Mike Dempsey]

Jit

This is the link you need to look at for a DRO http://www.max-t.co.uk/

Had very good recommendations on woodworking forums.

Mike

[paul mott]

Jit,

Most of the cheaper and small DRO's I have seen all seem to auto zero at switch-on and this would not be a lot of use for your application for knowing the table height.
A mechanical device such as a vernier with dial indicator may be a better choice.

Paul.

[Robert Walters]

I would think a Stainless Steel Dial Caliper might be able to be mounted on Jit's machine (on the cheap side),
Something like this... http://search.ebay DOT co.uk/380329846823

At least until a more permanent solution could be found.

[Dan Hintz]

Most of the cheaper and small DRO's I have seen all seem to auto zero at switch-on and this would not be a lot of use for your application for knowing the table height.
My $10 6" digital caliper from Harbor Freight doesn't reset...

[paul mott]

My $10 6" digital caliper from Harbor Freight doesn't reset...

I didn't say all Dan, just most of the ones i've seen.

Paul.

[Robert Walters]

My $10 6" digital caliper from Harbor Freight doesn't reset...

Till the battery dies at the worse possible moment =)

[Mike Null]

Dan

I look at your equipment list and somehow a $10 digital caliper doesn't belong--why not a Mitutoyo which is a professional tool.

For Jit's job a dial indicator should do the trick and they can be bought for $20 to $50 US.

[Rodne Gold]

I would imagine that if its only cardstock thats being processed , surely a fixed mechanical type gauge would do?

[Dan Hintz]

Dan

I look at your equipment list and somehow a $10 digital caliper doesn't belong--why not a Mitutoyo which is a professional tool.
I've been looking, but so far haven't found a price I like (the Tyler Tool sale was my latest attempt, but they were all sold out). If my laser's bed can only adjust to within a few mils, seems pointless to use a high-quality instrument to measure substrates.

[David Fairfield]

Horrible Freight had the Digital Mitutoyo calipers on sale this month, might be still on. I paid Micro Mark $20 for the 8" one some years ago, very precise and is one of my most used tools. For $20, I was skeptical, but its really an excellent and reliable tool. The longer ones are reasonably priced, too.

Dave

[Mike Null]

Dan

I bought mine a long time ago and paid over $100 so I know what you mean.

[Chuck Stone]

I've got a 12" Mititoyo, but I still end up using the iGaging EZ Cal Digital Calipers.
i think I got them at Peachtree woodworking or maybe LMS, I forget. I think
they were about $16, accurate to 0.001 which is all i need for most things in
the shop. For more than that, I go back to the Mititoyo

these don't auto-zero unless I kill the battery

[paul mott]

I have the Mitutoyo 150mm calipers and as fate would have it - they auto zero at switch-on as well :(

Paul.

[Dan Hintz]

Paul,

You've had some bad luck, man... every cheapy I've come across doesn't reset. I guess there are some advantages to using the cheapest junk you can find :D