Galvo vs Plotter

[matthew knott]

We have an Epilog a Shenui & a host of galvo machines, we pretty much never use the Epilog, the Shenui is new and getting a bit more use now, the Gavlos are the ones that 'print money' for us. Not many of you guys have galvo machines, I know they have some limitations but also stacks of advantages like no cermark for one. Is there any reason you dont have them, what puts you off?
http://www.youtube.com/watch?v=w1nKzF2w3Tg

Heres a good example, the software can automatically take in a spreadsheet and engrave the correct QR code, in this case just the serial number is changing, marking area is 200mm x 200mm (8 inches) and cost us about $18000. Curious on your thoughts
Cheers guys

[Mark E Wilson]

I'm sold. Interested in seeing more on the Shenui and barcodes. Does it do both Galvo & Plotter? Looks like it has a real large bed for just 200mmx200mm.

I have an older Universal X660.

[Scott Shepherd]

I've been saying for a little while now that we want one. Not because we should have one, but because I want one and think it's one of things that once you have it, it'll make you a lot of money. I contacted our rep, asked about it. I said "Where can I see one? Can you bring one and demo it for me? Is there someone close with one? Can I drive to see one within a couple hours?". The response I got back was "Sorry, I don't have a demo machine, I can't demo it for you, the closest person I know of is 6 hours from you and it's used in a high production environment, so I'm not sure you'll see what you want to see".

So I'd be interested, but it's hard to buy something you can't see. I saw one at a trade show a year ago, by some no name company. Other than that, only place I see them is youtube :)

[matthew knott]

Scott, they always seem to market these to 'Industrial users' and the plotter style to the 'small user - hobbyist user'. But there is a big cross over, i would have thought lots of you guys with a plotter style laser would find loads of uses for them. I think the cost is interesting, when i started a new machine that did this would have cost $70-80k so big bucks plus you needed 3 phase power and a water chiller. Now the cost have come right down with the advent of Fiber laser. In the same time the plotter style have not really come down that much. I was very impressed with the video you did of the tag engraving, interesting how certain jobs lend themselves to different lasers, the galvo comes into its own when you have lots of non engraved area, if we engraved a solid box of say 5x5 inches the galvo is not much quicker than your trotec, if we instead just engraved a checker pattern, (chess board) the galvo would take half the time of the solid, I guess on the trotec it would be about the same?

Mark, the software project may come to nothing yet, the idea would be 2 have one version that can run both as the galvo software is way more powerful than the plotter style, I think the plotter guys, especially trotec and epilog should adding some of the features. You can use complex work arounds in corel with macros and vb, but easy is king in my opinion.

[Dan Hintz]

Not many of you guys have galvo machines, I know they have some limitations but also stacks of advantages like no cermark for one. Is there any reason you dont have them, what puts you off?

Just so there's no confusion, the lack of need for Cermark is not due not to the unit being a galvo, but by it being a fiber laser...

I think cost of galvo units (compared to flatbeds), as well as the limited working area, has held most people back.

[Dave Sheldrake]

as well as the limited working area,

2m x 2m isn't too unusual now Dan, that said they are EXPENSIVE!! (mines not top of the range but costs near as much as the 3m x 2m Mitsubishi with a 10th of the power)

cheers

Dave

[matthew knott]

Quite true Dan, no advantage gained with galvos other than speed, and more powerful software. You can get CO2 Galvos also and you would need to use cermark to mark metal. My title is misleading

[Rodne Gold]

The issue with Yag/Galvo/small marking fields is that in essence , they are really useful if you are doing production marking or promotional branding etc..
For a lot of folk , like myself , that do jobbing , capital costs are too high (for a good machine) , but more importantly , there are others out there that have them and they are all fighting for a slice of that pie.
Over here it leads to cut throat pricing and low profitability unless you do have a large slice of the pie..hoping to get crumbs is futile as the other operators have more experience and have amortised the machinery.
FYI .. A 80w Co2 Galvo is around $6k Ex china , a 50w YAG is round $10k and a 10-20w Fibre is around $20k , not sure of what mainstream prices are..

[matthew knott]

One thing to bear in mind is the difference between a main steam fiber VS a Chinese is not the same as the plotter style. They are much much closer, and you could say you are comparing apples to apples. But this also shows up in the pricing as they are closer in price, with only a 50% or so saving. Rodney is quite correct that the promotional gift market is quite cut throat, but still healthy money to be made. The engineering side of things is much better, people prepared to pay a premium !

[Dan Hintz]

2m x 2m isn't too unusual now Dan, that said they are EXPENSIVE!! (mines not top of the range but costs near as much as the 3m x 2m Mitsubishi with a 10th of the power)

What's the dot size with a 2m F-theta lens (400um, give or take)? Typical dot size (for 1kum) is on the order of 20um for a 100mm field size, but that grows very quickly as the field size increases. There's a lot of power density lost as that dot size grows. A 30W unit at that field size would have less "oomph" than a half-watt unit at the small field size. You'll be waiting a looooong time waiting for that to cut ;)

[Dave Sheldrake]

Pretty much bang on Dan, 380um was the quote when I purchased the machine. That said it is fired by 600 watt fiber so not too bad for what it was bought for. The head is Vytek but the bed was built to order by another company.

I'm just going to import a CO2 Galvo from China to see what they are like, I'm expecting problems but the purpose it's being bought for means it only really has to last 3 weeks ;) Let's face it,a $6,000 Galvo isn't going to be much cop ;)

I do like Galvo steered lasers, my market doesn't usually involve much engraving though and I tend to pass on any engraving work I get.My next job is quite a few parts, once the job is sorted I'm going to fire it off to Matt to see if he wants the engraving for it.

cheers

Dave

[matthew knott]

Dave for 6K you will get (from china) a pretty good set of galvos, a generic copy of cambridge but good performance and XY2-100 digital control. A nice controller with good software, an ok scan lens, probably a ronar smith, will do the job well, and a pretty average glass tube. All packaged up in a working system. The rise/fall times of the glass tubes will affect the overall performance, but it will do quite a good job IMHO. We have a 30 watt galvo co2, we made it with a used coherent diamond and its a good workhorse, it only gets used about once a week but its more than paid for itself.

[Dave Sheldrake]

Going for an LG60 Matt from Weike, 60 watt Glasser + the usual "claims" ;) 300 x 300

Should be fun as I've never personally owned a Weike and want to do a review on their sales stuff :)

cheers

Dave

[Dan Hintz]

I'm just going to import a CO2 Galvo from China to see what they are like, I'm expecting problems

I'm intensely curious what the control software is like (especially compared to the software used for the Chinese flatbeds). I'm working on quotes now for a fiber, and the question has been raised about galvo versus flatbed. I deally, I could print from Corel directly (i.e., native driver, not a translator written in Visual Basic that never works perfectly and insists on translating everything to Adobe illustrator format first)... but next best thing is import a file from Corel into their driver software.

I've taken a real shine to SPI Laser's redENERGY G4 cartridges... lots of options there. I'm guessing I would need to use SPI's control program and they have standard control drivers for most galvos... downside to that is I'm stuck with however SPI has decided my workflow should be. Maybe it's good, maybe not so much... wish I could play with one firsthand.

[Dave Sheldrake]

I'll get a review done Dan soon as I have the machine. It's cheap...REALLY cheap so simple economics suggest I'll have some issues but time will tell I guess. The software is something I've never used (I've never even heard of it before looking at this machine)

The G4 L type looks really good , They are only a few miles from me (about 15) (I was in Hedge End today) so if there is anything you want me to drop in and get let me know :)

cheers

Dave

Ooo I just noticed they do evaluation machines for 30 days......that's tempting ;)

[matthew knott]

I'm intensely curious what the control software is like (especially compared to the software used for the Chinese flatbeds). I'm working on quotes now for a fiber, and the question has been raised about galvo versus flatbed. I deally, I could print from Corel directly (i.e., native driver, not a translator written in Visual Basic that never works perfectly and insists on translating everything to Adobe illustrator format first)... but next best thing is import a file from Corel into their driver software.

I've taken a real shine to SPI Laser's redENERGY G4 cartridges... lots of options there. I'm guessing I would need to use SPI's control program and they have standard control drivers for most galvos... downside to that is I'm stuck with however SPI has decided my workflow should be. Maybe it's good, maybe not so much... wish I could play with one firsthand.

Honestly when you get used to using a proper program written to control the laser with all the features it brings Dan you will never want to go back to a print driver. I won't go into all the clever stuff you can do but, a print driver just cant cut it as you need a higher level of control to get the best from.
We have a redENERGY G4 on loan for a development project, its a 85 watt pulsed with over 4 joules per pulse, it kicks arse! only downside is the beam quality is m2=5 ish, so it suits a shorter lens. Did this today, its 1mm deep
268446
You don't have to use SPI controllers, they are quite basic and if someone contacts SPI about buying engraving machine they just recommend a company that uses their lasers. IPG also make pretty nice fiber lasers. Dan if you want to try some demo software I can send you a link, but nothing beats sitting down and trying a machine to see the software and hardware link up.

[Dan Hintz]

Matt,

Expect a PM when I get a longer chance to sit down and put my thoughts together. I sent SPI an email asking for a quote, but I haven't heard back from them... if you happen to speak to one of the reps at some point, see if you can get a list of manufacturers in the US who use their lasers. I'll gladly take that demo software link, too.

What kind of removal rates are you getting with that 85W? I'm looking at a 20-30W system (M2 would be in the low 1.x range), and from what I can tell, 20W puts me in the 4-5 mm^3/min range for stainless (also want to work with aluminum, brass, and titanium). I'm only looking at going 1mm deep (+/-), but I imagine that will involve multiple passes at that power level... it seems 0.1mm/pass is the typical range. At that rate, small items will take me 30 minutes while the larger items I have in mind could very well take all day (literally).

[Bruce Boone]

I came close to getting an SPI fiber, but found the IPG worked the titanium better. The SPI was continuous, and the IPG quasi continuous mode allows pulses 10 times higher power in 1/10 the time increments. It is able to still run air cooled that way, and you get massive peak power. I sent samples to both and although the SPI had a finer beam, it did best fot very thin stuff like stents. It couldn't handle the 7mm of titanium requirement.

[Rodne Gold]

2 years ago , I had a demo of a 20w fibre at shenui (their galvo platforms were pretty good as far as I could see with their Co2 and Yags ) and I asked them to cut thru a piece of 1mm or thinner aluminium , it took like 10 passes to get thru , but the passes were real quick... what concerned me more was the heat of the piece after .. when they did engraving , deepish , if you turned the piece around , you could see the impression on the back side.

[Dan Hintz]

I'm sending out a handful of samples to be deep engraved... I'm interested in engraving times, chosen parameters, as well as final quality (such as the rear impression you mentioned, Rodney).

[matthew knott]

I will work out the material removal rates for you, .1mm per pass is optimistic, but i guess it depends on the speed, we normally run a high speed with loads of repeats, it helps keep the HAZ damage down as the heat is more evenly distributed. Deep engraving into thin material is almost impossible. Stainless is awful and has to be clamped down, aluminium is better but you still get damage on the back. At the end of the day the laser is just heat, cold laser technology will be the future, but way too expensive right now.

[Dan Hintz]

So let's say 0.05mm/pass on aluminum with a 20W... what would your rough speed be (ipm)? I'm looking at a flatbed to keep my options open, particularly since most of my work will be deep engraving, not marking (where a galvo would be much faster), so speeds will be very slow.

[matthew knott]

So let's say 0.05mm/pass on aluminum with a 20W... what would your rough speed be (ipm)? I'm looking at a flatbed to keep my options open, particularly since most of my work will be deep engraving, not marking (where a galvo would be much faster), so speeds will be very slow.

OK, I engraved a box (as seen in the picture) 28 x 5 mm with the text inside, with a 30 watt fiber it to 7 minutes to go in .5mm, I think the speed was 600mm/sec and 60 repeats, 254mm lens. On the 85 watt laser it took 5mins to go in .95mm but with a 100mm lens

One thing that really helps with deep engraving is to change the hatching angle every pass, i use 45 degree increments, this is not possible on a flat bed as you only have one angle of attack.

[Dan Hintz]

OK, I engraved a box (as seen in the picture) 28 x 5 mm with the text inside, with a 30 watt fiber it to 7 minutes to go in .5mm

I estimated roughly 50 minutes to do 1mm deep on a 5mm x 50mm range with a 20W... scaling those numbers up sounds like my estimate wasn't too far off. I expect to use an 80mm lens, so power density should be quite a bit tighter than your 254mm lens... I'm hoping for a much faster removal rate because of that.

[matthew knott]

I would think the lens would help a lot, we have a 100mm lens so i will try it tomorrow, should be close to an 80mm, i will try a 5mm x 50mm box and measure the result, someone else was working out the 85watt, i will post their results to. You can't beat a traditional cutting bit for deep engraving, but you cant get the quality of a the laser, its as good as EDM. It really depends what your doing, and sometimes a laser is not the right tool, but sometimes its ace! What are you hoping to do?

[Dan Hintz]

I will be looking for extremely fine detail in tight areas... no bit could ever hope to touch what I plan on doing. I'm very keen to learn what you get with the 100mm lens... any chance you can remove the cross hatching and just have it do passes in the same direction each time, try and get it as close as possible? Thanks!

[matthew knott]

I will be looking for extremely fine detail in tight areas... no bit could ever hope to touch what I plan on doing. I'm very keen to learn what you get with the 100mm lens... any chance you can remove the cross hatching and just have it do passes in the same direction each time, try and get it as close as possible? Thanks!
Can do, it won't be quite as deep and the bottom won't be as smooth but it will still work, I only have 30 watt lasers running right now, but at 80% power they are pretty close to 20 watts. The SPI 85 watts is big bucks, its not out for sale yet but estimate is £19k (x1.5 for $). A 20 watt source can be had for less than $8k (not spi)

[Dan Hintz]

Hoping you find the time to try out those new settings, Matt... once I find a suitable brass road to join the stainless and aluminum rods I already have, I'll be sending them off for some test cuts.