Ideal Laser Engraver?

[Mike Null]

Two points: I understand that some are having good results with Chinese machines. Perhaps the best example is Rodney Gold in S. Africa. But Rodney has several of them so if one goes down he's not out of business.

Secondly, I had my tube rebuilt two years ago (it was 8 years old) and I paid $3000 to have it done. There is another place which advertises $1100 and I may try them should I need to have the tube rebuilt again. But only after more research.

It was not my intent to exaggerate but it does seem that most of the people who have purchased Chinese laser have issues of one type or another.

[Gene Uselman]

I have a great Chicom laser- very well built with good parts (EFR tube and 3phase steppers, etc) and once sorted (and the DSP changed from Leetro to Ruida- as I prefer RDworks software) I am delighted with it. So, yes the DSP can be changed or if you are buying direct the mfrg should be able to provide most machines with whatever DSP you like. If you are considering a Chicom laser, I would recommend these videos- https://www.youtube.com/channel/UCqC...nElPTUnxX0mD5A - he is very thorough and if you keep in mind that he bought a bottom rung laser from Ebay, there is a lot of free info there. Gene

[Dave Sheldrake]

That's over there Mike, tube refills are horrendous here. Near $10,000 for a 120 watt for my speedy 300

[Dave Sheldrake]

I was a little wary of AddSharks because I couldn't find much info on them, that's not saying they are not reputable dealers. Thanks for your opinion.

I will have a drive up to HPC once Epilog and Trotec have shown me what their machines can do but I will also keep looking at the possibility of a chinese import.

At the minute the chinese manufacturers I have managed to shortlist are Weike, Thunder laser, Ray Fines, there may be more but I am still doing my homework.

Am I right in assuming that 'IF' I contacted a chinese factory direct for a quote, that any piece of hardware for example an AWC 708 controller can work with any tube etc, etc or is it a bit more complicated than this.

Daz...

All of the current Chinese controllers (DSP's) will work with any of the mainstream DC tubes (and RF tubes if you go that road) all they do is supply either a PWM or 0-5V signal to the high voltage supply to fire the tube so it doesn't actually know what tube it is sending the signal to (there is no feedback)

Weike aren't what they used to be, support is sporadic and mostly just read from a "Fix your laser 1-10 sheet", RayFine aren't bad, Thunder are pretty good. Shenhui are big manufacturers as well (one of the biggest) HX won't sell direct (they are the HPC Machines)

Trotec are excellent machines for engraving, even those though will struggle to get close to the speed of a Galvo (Galvo's have much smaller working areas though)

I love my Trotec but I cannot justify the cost of a new 200 watt machine just to refill the tube.

[Mike Null]

Dave

That sounds to me like a lucrative business opportunity for someone with your expertise.

[Dave Sheldrake]

Dave

That sounds to me like a lucrative business opportunity for someone with your expertise.

Looked at it Mike but to be honest at 50 I'm planning on doing less these days not more and retiring inside 5 years, I've done some tube filling and built resonators for fun but after the year I've just had I decided I want to spend more time at home not less
The last year has made me realise what is really important and what isn't

[Kev Williams]

Here is my overly simplistic and probably not entirely accurate descriptions of the differences between Western metal and Chinese glass lasers, as I see them...

A Western laser is like driving a new BMW. Easy to figure out, easy to operate, smooth controls, does its intended job wonderfully.
A Chinese laser is like driving a 1982 Peterbilt. Very tall learning curve, a bit cumbersome shifting that 13 speed and 2 speed rear diff, but it gets the job done, if somewhat brutally

A Western laser's beam quality is kind of like cutting skin with a scalpel.
A Chinese laser's beam quaility is kind of like cutting skin with a chef's knife...

Ever watch an SUV's LED turn signals in its rear-view mirror work in relation to the regular incandescent bulbs out back?
...The LED's turn on and off instantaneously, while the incandescent's appear to turn on and off in slow motion...

DC glass tubes and RF metal tubes work kind of the same way:
--DC glass tubes are the incandescent bulbs--
--RF metal tubes are the LED's....

RF tubes always(?) fire in pulses. I think I saw somewhere that typical RF lasers like we use are capable of firing up to 16 million times per second. On a Trotec or Gravo running at 150" per second, that's 106,666 dots per inch. So I guess 3200 DPI is childs play

DC tubes are always(?) either ON or OFF, they don't pulse.

Because RF tubes fire in pulses, each pulse fires the same as the last one, equally spaced. With the instant-on-instant-off nature of the pulses, nearly all the burn the laser puts down will be equal regardless of engraving speed...
Because DC tubes don't fire in pulses, and by their not-so-instant on/off nature, engraving speed is a huge issue...

Engraving speed affects the 'total burn' on an RF laser. Slow the speed, get more burn. But, ALL the burn, everywhere you look, will be almost identical. I say 'almost' because very small details can suffer regardless...

But on a DC laser, engraving speed affects the 'average burn'. In most cases the 'average burn' of a DC laser will be perfectly fine, but under magnification, you can see variations. This is because of the slow-firing nature; it takes quite a bit of time (relatively speaking) for a glass laser to reach full power once it's on. When spanning short passes, say the vertical bar of a "T", the laser will be barely getting hot before it's time to shut off. However, on the long horizontal bar of the "T", the laser can reach full power before well before time to shut off. Therefore, the long bar will be visibly more burned than the vertical bar. And the faster you engrave, the more pronounced this issue gets. (This issue gives me fits with Cermark, get the narrow bars okay, the long bars overburn. Get the long bars okay, the narrow bars don't burn enough)

An RF laser running at 500 dots per inch on the X axis is going to put down the same equal burn pulses across the short bar as it does the long bar, whether running at 1" or 150" per second.

In another thread, I posted up these pics of some wood I engraved with my glass laser as a size test. It's also perfect to demonstrate the "slow motion" issue with glass lasers. I did the 'deeper' and 'shallow' engravings at different power settings, 12% for the shallow and 25% for the deep. All engraving was done at 400mm/second. You can clearly see in both deep and shallow versions, as the lettering got smaller, the actual burn reduced substantally. In fact, the 3 smaller 'shallow' engravings I had to do a second time. Note the 5mm shallow has depth and is fairly dark, while the 2.5mm shallow is nearly invisible. The last 3 are only visible because of the second pass!
trimaple3.jpgtrimaple1.jpgtrimaple2.jpg
Since the power didn't change, the problem was the speed. The laser simply couldn't keep up.

So that said, I just had to run the same test with my 12 year old Metal LS900, here's the results...
Note I have the shallow and deep backwards, oops! But that DID make it easier to figure out which machine did which!
900wood1 (Large).jpg900wood2 (Large).jpg900wood3.jpg

First pic, glass left, metal right-- but as you check out the engraving my metal laser just did,
you'll note there's virtually no variation on the actual burn between engravings, save for some small variations with the smallest text.
Metal laser detail is better too, but my Triumph doesn't do too bad!

I'm sure Chinese machines are capable mechanically of much higher than the 500-800 mm/second max speeds. I believe the reason for the slow max speeds has a lot to do with the fact the lasers themselves can't keep up. I can, and have run mine at 1000mm/sec, and the engraving quality was much less than stellar...

So that's my take on the differences between metal and glass lasers. For what it's worth

[Keith Winter]

Good easy to understand explanation Kev!

[Dave Sheldrake]

Not far off Kev but RF tubes are available pulsed / Cw but it's a bit more complicated than that.The beam does go on and off in an RF but that doesn't mean it's a pulsed laser. The rise time of an RF is in effect instant......signal-rise-lase where in a DC depending on the gas mix and temperatures it runs signal-rise-peak-lase

The problem is many of the terms involved get used in more than one place (like Beam Frequency and Pulse Repetition Frequency) one controls the wavelength, the other is how many PWM cycles are used for example.

Then it all gets really complicated when you take glass tubes like the GSI SLC series, twice the price of the same power in RF but still DC tubes and capable of huge powers and beam quality (far above what a cheaper RF in a trotec will manage)

In general comparing a cheap Chinese tube (RECI / EFR etc etc) with an RF is moot as a decent DC like the SLC exceeds what even a good RF from Syrad will do. In general it comes down to quality of the tube manufacture and while excellent even EFR are well below that of an average RF. Then again they should be, a 240watt EFR is $4,000 a 240Watt RF is closer to $30,000

There are also a lot of DC powered Galvo's that will peak at 9,000mm per second so the machine speeds don't come close to what the tubes will actually do. (most of it is the much higher weight of the optical head on a DC that makes it slower)

As a rule, affordable tubes of the same output, the RF will give better results but at a higher price.

[Keith Downing]

Hi,

I have been roaming around the forums for a few weeks and reading up on laser specs and reviews, many thanks for all the information that as been posted.

I am a small sign maker, home based and I am in the market for a laser engraver and cutter. I have a couple of demo's booked with Epilog and Trotec but I am willing to consider the idea of a chinese laser (because of the cost savings). Part of my business already imports goods from Australia, Germany, Italy etc, so I am happy to consider an import. Space is very tight in my small workshop i can accommodate approx a 1200mm wide laser unit.

From what I have read, i believe I would be looking at an 80W laser to cover cutting and engraving 1/4" 6.35mm Oak, Acrylic, MDF, other woods etc.

EFR tubes seem to be well thought of at this moment on the forum. Not sure of the best controller, I am still reading and learning.

Speed is not essential but engraving quality, finish of the cut material and machine uptime are essential!!!

Is there any chinese spec machines that can match or come close to Epilog / Trotec machines.

Thanks in advance

Daz...

You've gotten a lot of good advice/info here, so I won't repeat anything already stated.

One thing I will add though: You say speed is not essential, just engrave quality. But, if you'll be doing a lot of work that is engraved (like sign makers often do) that may turn out to be one of the MOST important factors for you.

I have a boss laser, and I like it a lot. Very good value for the money, and having the US support for the Chinese machine was pretty close to priceless for my first purchase (and experience with laser engravers).

However, the one weakness (and really the only one so far I've experienced) is that it is extremely slow doing high quality engraving compared to a high end US machine. This may not seem like a big deal at first, but it is generally a pretty good rule not to leave a laser unattended while it is running. So, you're standing there dedicating your time to the project as long as it is running, every time. On my laser to do a high quality 8x26 inch engraving (we do a number of signs for weddings this size) it takes about 45+ minutes to run. It looks great at the end, I would never pay another cent to increase quality on wood engravings. But that extra engraving time really cuts into profitability for custom work, and all but eliminates the possibility of competing for anything "mass produced". When someone else with a faster laser can create 3-4 signs in the same time I can create 1, it's an uphill battle to price competitively no matter what I do.

Now it may not matter much if you're doing mostly cutting, really high end custom work, or small metal or part marking; but for me speed of engraving is the only thing that makes me really consider buying another machine or upgrading mine.

But maybe it's just based on the value I place on my time; and the formula may be different for others. But, if you're doing this to increase your productivity and offerings for a business, it may be a major concern for you as well. Anyways, just my $.02.

[Rodne Gold]

I would never go for an expensive "westernised" machine again , got a whole herd of chinese machines that work exceptionally , easy and cheap to fix . engraving quality is as good as any other machine's , speed a little slower , price a WHOLE lot cheaper
my 2 shenhuis have been going strong for 5 years with only lens and tube replacements and my longtai's have performed flawlessly .. a single tube replacement due to operator error is the only maintenance
The machines in my facility are borderline "abused" in terms of maintenance and it make little difference as to their performance.
I bought my 6 x 60w 600x400 Longtais for under $15k door to door...(for all 6) , we have 4 commissioned and 2 still in the crates..
Lasers are tools , not investments .. at $2.5k per machine , if i get a years worth of high production I have made 10x their worth per machine or more.. if i had a catastrophic failure on any one , I would just dump it and buy another.

[Bert Kemp]

Keith I don't really think its necessary to stand by and watch it engrave wood, theres little if any chance it will catch fire while engraving. Cutting is were the real risk lies and cutting speeds are similar for both western and Chinese machines and both should be watched while cutting.

[Keith Downing]

Keith I don't really think its necessary to stand by and watch it engrave wood, theres little if any chance it will catch fire while engraving. Cutting is were the real risk lies and cutting speeds are similar for both western and Chinese machines and both should be watched while cutting.

I've thought about this a lot myself. And eventually plan to add a camera to allow remote monitoring. But most people say it's just not a good idea to leave the machine completely unattended no matter what function it is performing. And, as my shop is attached to my house, I tend to err on the side of safety.

[Bert Kemp]

Better safe then sorry. My laser is in the house and when engraving I'm never more then a few feet away, usually sitting at the computer right next to the laser, sometimes I'll get a coffee in the kitchen but I still can see the laser, I just don't hover over it, but when I'm cutting I stand right there and watch and if I have to leave it for any reason I pause the job, then continue when I get back.

I've thought about this a lot myself. And eventually plan to add a camera to allow remote monitoring. But most people say it's just not a good idea to leave the machine completely unattended no matter what function it is performing. And, as my shop is attached to my house, I tend to err on the side of safety.

[David Somers]

Darrell....apologies. I missed your question until just now.

By a well adjusted machine I mean your lens and mirrors are properly aligned. And that the focus spacer/gauge that came with your laser is accurate which you check by doing a ramp test for that lens (a search for ramp test in the forum will get you the instructions.) And your lens and mirror are clean and kept that way. Also, that your table is on the same plane as your gantry XY plane. In my case I have both an aluminum knife or slat table which sits under my steel honeycomb table. I removed the honeycomb table and then put my lens in one corner of the knife table and used my focusing spacer to get the lens focused on the top of the knife edge in that corner. Then I moved the lens to the far end of that knife edge and adjusted that end of the knife edge until it was in focus as well. Note I did NOT adjust the lens tube. I brought the top of the knife edge into the focal point using my spacer. Then I repeated that process on each of the knife edge blades so each and every blade was at the same height relative to the bottom of the lens tube. So the knife edge table was now on the parallel to the plane of the gantry XY axis. Then I placed the honeycomb back on and rechecked its 4 corners with my space to be sure it was also parallel to the plane of the gantry. This last bit doesn't actually count towards a well adjusted machine, but I drilled though my honeycomb frame into my table frame and threaded the holes in the table so I could bolt down the honeycomb. Then I added straight edges on the left, back and right sides that are aligned with my X and Y axis. Now I can remove the honeycomb to clean and put it back exactly where it came from and have guides that are square to my XY axis. I personally like things that are square and repeateable.

I also went through the machine after getting it and made sure every electrical connection was snugged down and secure. I added an extra light to the inside of the cover for my convenience. And I added a milliamp meter connected to my laser EFR tube so I can easily see how much juice is flowing through it, and I know for certain how my manufacturer set up their power settings. I won't accidentally over power my tube. Plus I have a cheap diagnostic tool in place if I needed it.

Those are the things I did to get it all adjusted. The main things though are the mirrors and lens alignments, and the table being parallel to the plane of the gantry.

And on a Chinese machine, unless you have gone through the trouble to locktite every screw, you will want to check all these alignments now and then to be sure they havent wandered. So far, mine havent wandered. But then I locktited everything but the mirror/lens fittings. (I know....bordering on OCD with a soupcon of anal retentive....<grin>)