Buying a Shenhui SH-G690 Laser Machine

[Kaushik Ghosh]

Hi Everyone, I am new to this forum and lately have been reading up quite a bit on this forum as I plan on buying my first laser cutting machine. My work would mainly consist of cutting paperstock, acrylic, MDF and wood (plan to do less of engraving initially). I have zeroed in on Shenhui Laser Machine (Model SH-G690) with 80 watt RECI tube and plan to buy it direct from their factory in Lioacheng, China and have been in touch with Sofia Liu on Skype. She has given me the following configuration:
LASER ENGRAVING MACHINE SH-G690 (80w-100WXS2 /220V EURope plug/20F50.8)
Configuration: Gaz output on back door
1. Laser tube RECI W2X1.25m.
2. Motorised up & down table
3. Alum knife table with Honeycomb.
4. Air pump (Resun)
5. Worktable size 900x600mm
6. One visible red dot
7. Stepper motor (stepdriver)
8. Taiwan PMI guide rail & Germany belt.
9. Air assist nozzles
10. LaserworkV8 supported Coreldraw & AuotCAD.
11. CW3000 water chiller.
I would like some advice from the forum members to guide me on some of the technical terms (80w-100WXS2 & RECI W2X1.25m) and would also like to have some advice regarding which optional accessories to order, which ones to replace/change from the above list, which extra lenses to order (ZNSE), spare parts, etc. Also I would like to know the price difference between the CW3000AG and CW5000AG chillers and some advice about Master Airbrush TC-20T air compressor.
Thank you all in advance.
Kaushik

[Dave Sheldrake]

To be honest you need to learn a lot more before buying a laser, of late there has been a big influx of folks who buy machines knowing very little about them or what they do or even what they can and cannot do.

30 minutes research on google or even the search function here will yield most if not all the answers.

A lack of research will lead to problems very quickly and also increase the possibility of somebody getting hurt badly.

[Bert Kemp]

another thing it would be nice to know your location. You say your getting a 3000 water chiller if your in a warm area or even a semi warm area this chiller will not work for you. This chiller only makes your water room temp and you want to keep water temp below 65F or lower

[Kaushik Ghosh]

I am located in India, very hot conditions here, so ideally would want to go for a CW5000AG chiller.....that's why was wanting to know about the difference in price between the CW3000 and CW5000 chillers.

[Bert Kemp]

Well you definitely want the better chiller price beside the point. If price of the chiller is a factor then you might want to rethink buying the engraver as if you can't keep the water cool the the laser will not last and you'll be buying tubes all the time. The price difference will pay for itself in no time. You'll have to ask your vendor about price.
What advice do you need on air compressor this I assume is for air assist.


I am located in India, very hot conditions here, so ideally would want to go for a CW5000AG chiller.....that's why was wanting to know about the difference in price between the CW3000 and CW5000 chillers.

[David Somers]

Kaushik,

Think of the CW3000 as being a heat exchanger only. Water is pumped through it and goes through a series of tubes with radiator fins. As Bert said you can ONLY get the water to whatever ambient temperature is this way. You could get around this by simply putting a 5 gallon bucket of water with a frozen plastic milk container of water in it in line with your cooling system. Keep another frozen container of water in the fridge so you always have one ready to swap out. But if you are going to do that you could do with just a good water pump instead plus the water bucket and ice and skip the CW3000. My thought though would be to use a CW5000 which is an active chiller, meaning it has what amounts to a refrigerator in it to actively cool the water.

If you can get it, and with Dave Sheldrake's concurrence, I would swap the RECI tube for the same power tube from EFR. When I bought my unit Dave strongly suggested that the EFR tube was a better quality tube and longer lasting. (Dave...is that still the case please?)

Is a 900x600 table an adequate size for your needs, both now and later on? The cost to bump up to the next larger size of 1200x900 is pretty minimal. At least here in the Seattle area of Washington State in the US, the 1200x900 size table has a better resale, all things being equal. I have a 900x600 however because I physically didnt have the space.

Regarding the wattage of the laser tube. The sweet spot for power between engraving and cutting is 80watt. If you are primarily interested in cutting you can go higher but you will find that you cannot reduce the power of the tube enough for fine engraving in a lot of circumstances. If you want to do both shoot for the 80watt.

Will this laser have pass through doors so that you can run longer lengths of material through it if needed? Since you seemed mostly interested in working flat stock that might be handy. I would actually assume that is standard on a Shenhui but would ask to be sure.

I would not bother ordering a spare tube. They have a shelf life and unless you were going to be extremely sensitive to a down machine it is not worth it. Overnight (or as fast as you can) a new tube if needed. Both EFR and RECI tubes should be widely available.

I would have spare lenses. And my own bias is to have tubes for each lens size you want. They are cheap to get with your order. A standard 2inch lens is fine for most work. A 1.5" lens may be an advantage with its finer dot size. But you will need a special lens tube to use it. There are reasons for using a longer lens like a 4" or 5", but most people do not need that.

Other good spare parts are belts and chains. Also, any fuses they use in the machine should have plentiful spares in case they are not standard and easily obtained in your area.

I might also ask if they can put a power meter on it for you if it does not have one. That can be useful information. Thought not necessary. You can always add a miliamp meter later on.

I would also make sure that it will set setup for whatever your power is in India? Chinese native power is 240V. Meaning that the power at a standard wall outlet is 240V. Because of that, their plugs look like what might be considered a standard 110V here in the US. That can cause confusion. Be sure your sales person understands what your power standard is and matches it.

I would also be tempted to have a dedicated circuit for your laser with nothing else plugged into it. If your power reliability is iffy you might also want to get a voltage regulator for the machine to help protect it. Or at the very least a good surge suppressor. A voltage regulator would be better. You are trying to protect your circuitry which is expensive to replace.

I will have to rely on others for this....but I do not believe I would rely on an airbrush compressor unless that is what they are providing to you and are confident in it. Airbrush compressors are generally not made for continuous duty. Think about how an artist works with an airbrush. They will spray small areas, on and off, on and off. They rarely go for really extended time periods with the compressor running all the time. If you are a business you are likely to have the laser on all day however so you want a pump with an adequate duty cycle for that kind of use. A solid aquarium air pump with an adequate capacty would be a better candidate since they are designed to run continuously 24x7. What pump are they offering you?

OK gang!! Lets hear some other comments??? I need to run and cant babble much longer. Kaushik....I would second Dave Sheldrake's suggestion that you dig deeper on this forum. The more you dig the more thoughts and ideas you will have.

Have you used a laser before personally?
Is there one near you you could go watch and ask questions about?
Here in the US, and especially Seattle, we have facilities that offer a fairly inexpensive membership. They are often called community shops, or maker shops, or some similar term. For a modest monthly fee you can use any of their equipment, which typically includes a CO2 laser among many other tools. This might be a good thing to check out if this type of facility is available to you so you can test out some of your production ideas, get a feel for Corel Draw or Adobe Illustrator and see what is really involved in your business idea. Then you will have a better idea about what you might want in a laser, as well as if a laser is really suited to the work you want to do.

Good luck to you!!!

BTW... Where are you in India? I only ask because I just had a new neighbor move in who is from Bombay. His parents are here visiting for a few months so it has been fun talking with them. He loves Seattle and is staying here. He loves our cool dry weather compared with Bombay, and has fallen in love with our mountains and the ocean that surrounds us.

Dave

[Kaushik Ghosh]

Hi Dave, Thank you so much for your prompt response. I am still on the learning curve and look up to all your advice on this forum. I have been reading up a lot lately on this forum and the informative posts have been a goldmine for me. Looking forward to all you forum-members' input and advice from time to time.

[Bill George]

I am curious with the vast country of India, no one else has a laser and can answer questions?

[Dave Sheldrake]

Hiya Kaus,

Get as much information as you can find :) suck up every page and every site you can find that offers help and advice.Every minute you spend learning now will save you hours later when things go wrong ;)

[David Somers]

Kaus!

Dave Sheldrake is on the spot. In fact....although a bit excessive....I lurked and asked questiona and participated in this forum for about a year before I bought. By the time I bought I felt confident in what I was doing and getting, and when it arrived it was almost a familiar tool rather than a new toy that I had no clue about. And that was thanks to Dave and Scott Shepard and Mike Null and countless others here being patient and helping and being kind about me trying to help out in return as I learned. To be very honest, without the forum and the kind and knowledgeable people on it I am not sure I would have bought a Chinese laser, or a laser of any sort.

[Robert Bonenfant]

If your new to laser cutting ...

I would suggest coming up with a handful of items that you would like to create and find a local shop to make them. See if this is what your looking for, tons of people buy lasers thinking they will spit out amazing finished products and produce tons of cash. Laser cutters/engravers are a great tool to have but in my mind they are like a table saw. They are capable of making money but you have to be very creative or know how to market your machine. With a 80 watt laser tube your limited to cutting upto 1/2 but you probably wouldn't go past 1/4" on most materials (Cutting time would be too slow). I started with a 80 watt machine and found myself calling the dealer and upgrading to a 130 watt a month later (Wasted $2000 on the 80 watt setup). Like other users have said it really depends on what your making because these machines hit there limitation quickly when working with a wide range of materials. As far as spare parts you really shouldnt need any, maybe a set of mirrors and a lens. If your gonna use the machine daily for long periods order a second Laser tube or ensure you can get one quickly - Nothing worst then trying to finish a large order or project and your tube goes - In the US Ive had them overnight ed not sure how long china would take to India.

Robert

[Bert Kemp]

ordering a second tube is not a good idea, these tube have a shelf life and the warranty starts from the date stamped on the tube. If your first tubes dies after a year of use and you put the spare in and its dead you have no recourse but to buy another and pay for it. Most anywhere you can get a tube in a day or 2.

[Bill George]

Sounds like he does not have a local shop, nor does he know anyone with a laser. I think he is on the ground floor in his country for using and making laser products.

[Bert Kemp]

Try looking here http://laserlabindia dot com

[Kaushik Ghosh]

Thank you so much for your invaluable advice. I am also based in Mumbai in the suburb of Goregaon.

Can somebody kindly throw light on the spare lenses to go for if I go for a 1290 machine with 130 Watt (W4) RECI tube. The Chinese rep says that 63.5mm is the standard lens that comes along with the machine. Also, how many spare mirrors should I go for to have in my kitty?

[Rodne Gold]

5 spare lenses , 1 spare mirror
When I was at the shenhui factory , 5 years ago .. there were 2 youngish indian guys undergoing training.. they were the shenui agents in India...

[Kaushik Ghosh]

Hi Rodney, wanted to know the diameters and focal lengths of the spare lenses that I should go for in addition to the 63.5 mm standard lens for 130W RECI (W4).

[David Somers]

Kaushik. Since the laser company providing you with the machine also provides you with whatever their standard focal length lens is, they will know the diameter of the lens you need. If you ask for different focal length lenses in addition to their standard lens they will know the diameter for those as well, assuming they are different. Just for your records you might ask for the diameter they provide so you have that for later use.

If the different focal length lens(es) you get require a different lens tube configuration you might be sure they provide the tube as well. For example. In a standard CO2 laser a 2" lens and a 1.5" lens will likely require 2 different tubes. The distance between the lens the the surface of your material is short enough with the 2" lens that a standard lens tube cone is often too long so you end up having to get a tube with a shorter cone on it. Or with the lens mounted down lower in the tube.

I dont have any experience with fiber machines so I will rely on others to guide you on your choice of focal lengths that come in handy.