# laser cutter questions



## CliffyJ (Apr 29, 2009)

I'm interested in getting a laser cutter, and am looking at the Chinese units on Ebay / Amazon. I need to be able to cut up to 22-24" long parts, so the 500x700mm units are attractive. I'm not going to be able to get an Epilog or Full Spectrum, because I need to stay near $2k. 

I've heard bad things about the units, such as the laser tube going not lasting at all, the software being poor, bad mother boards, etc. But, I've heard good things as well. So, if you have some insights, I'd be grateful. Here goes.

Vendors / manufacturers: any that need to be really avoided?

Reviews: With all these units being sold, why the absence of Ebay reviews?

Support: I don't see any email addresses, support web sites or forums specific to the manufacturers of these (except one: hflaser.com). Anyone had successful support contact, and if so, with whom? Anyone found a helpful forum or two? 

Control: any opinions on what software to look for / avoid? I'll be using DXF files. Some cite AutoCad output or DXF, and that's a gotta-have for me.

Power: I need to cut up to 1/4" plywood and acrylic. Is 50W good enough? 

Functionality: Some units mention only engraving, some only cutting, some both (which I'd like). Is there actually a diff? Do I need to make sure I get a unit that says it will do both?

Motorized up / down (vs manual): What's the purpose? Is that a sort of auto-adjust for changing material thicknesses?

Sheet size: When they cite a working size (say, 500x300mm), is that the size of material you can shove in, or what the laser can actually cut to?

Installation: are these the kind of thing you can stand on end and maneuver with a furniture dolly, with a couple people?

Here's the reason I'd like to get a 700x500mm unit. The main purpose of this would be for large mining structures (served by the V&T) and other buildings on the layout. I did an example pattern set using 300x500 and then 500x700. 



















I learned from this exercise that, for this particular structure at least, 
- The larger unit would save gobs of time in material pre-cutting and machine loading
- And, require far fewer material splices
- Slight savings on material, due to joint avoidance inefficiencies w/ the smaller unit 

Sorry for the long-windedness, and thanks for any pointers & opinions.

Best,
===>Cliffy


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## toddalin (Jan 4, 2008)

You need to consider the cost of materials and in doing so, standard sizes that reduce your cost per piece.

Industrial Plastics sells single sheets in 1' x 1' ($5 for 3/16") and 1' x 2' ($10 for 3/16") at reduced rates because these are often odds and ends, and just easy for them to work with. The actual size is ~1/4" short of these dimensions. In fact, no one will guarentee your cut to _exact size_ (~1/4"), so you need to plan for that. Also, when you walk in there, there are tons of odds and ends and they tend to be just under 2' long. These go for $3.00/# regardless of type plastic/shape/size.

A larger bed also reduces waste of materials because what wouldn't quite fit on a smaller piece, requiring you to buy another piece for a small bit and you end up wasting the rest of the sheet, may fit on the bigger machine.

Also, if you can help it, when cutting a piece you really don't want to cut all the way to the end because the paper curls and burns leaving a messyier looking piece.

The biggest bugaboo I have with the Epilog is that the table sags toward the center. Because of this, cuts toward the center don't maintain focus, and the piece doesn't cut all the way through. Also, the area of acrylic that it is cut near the center will then sag into the table and pull away. So when the next cut is made, this portion of the material is now in a slightly different place and the cut does not come out true. Just today I made a shim from a couple pieces of brass to compensate for this sag. There is a lot of experimentation/waste involved.

... And this is supposed to be a quality piece of equipment. I imagine a cheaper system could be a real nightmare.


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## CliffyJ (Apr 29, 2009)

Those are GREAT pointers Todd, thanks so much. 

Maybe someone can speak to the sagging issue on Chinese units?

So, I need to leave margins around the parts... But for big walls, can't I use 2 edges of the stock, and run the laser to that edge? Or maybe run the laser just short, and leave a little material to snap/sand off?

For stock sizes, I was planning on getting full 4x8 sheets from the local plastics supplier (Piedmont). Not sure about nice MDF or plywood, haven't looked into that. But to pre-cut the 4x8's, I was expecting to do it myself, or pay the cutting fees. Not sure what those fees are.

Thanks again!


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## toddalin (Jan 4, 2008)

CliffyJ said:


> Those are GREAT pointers Todd, thanks so much.
> 
> Maybe someone can speak to the sagging issue on Chinese units?
> 
> ...



You can share a common line no problem. And you can put two lines fairly close together (maybe a couple millimeters).

In addition to the paper curling when working by an edge, the cut material itself leads to a very thin piece. This piece will then catch fire.

If you open laser to put out the fire, it will stop cutting and you "loose your place" as the progress continues. If you let the fire burn, the thin piece will melt to the other surface that you want leaving it a mess to try to clean up. I did this twice today woring too close to the edge trying to make the most of previosly cut scrap pieces. 

If this material is still molton, (right out of the laser) you may be able to quickly scrape it off. If it dries, it becomes one with your piece again and you have to try to sand it off or???

I did this today. It took over 2 hours. The boards are cut by running the laser at te hhighest speed, twice. Then all of the interior lines are removed and the laser is set to cut at "8" for the 1/8" and "4" twice of the 3/8".


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## Michael Glavin (Jan 2, 2009)

Todd

Does the laser have air or gas assist? This add on feature allows the user to process combustible materials, materials which produce combustible byproducts and helps mitigate smoke and enhances debris removal at the lasers path.

Michael


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## denray (Jan 5, 2008)

Cliff
I have seen several of these chinese lasers on ebay, i have heard only negative on them
Now the commercial machines i have seen at the large trade shows that we exhibited in, are much
different quality with support and the basics that you have mentioned, but not at your price you mentioned.
I am going to say what you already know, you do get what you pay for. 
I know the length of life of the tubes, are hugely different, in life and in price. I know when I change a tube in one of my Epilogs I drop 1800 bucks. but we run 3-6 hours per day, and get 2-3 years per tube. 
I have heard, (you know what heard means} that the cheaper Chinese tubes last weeks in the usage we do.
The commercial chinese units will use the better tubes. still less costly than epilogs.
The commercial machines run about half of epilogs price, but have the features you are looking for.

Now for a different page of this book. 
I will always own a laser, the most fun tool / Toy I will ever own. But we buy them for business purpose. 
BUT, you have the ability to do what takes the longest to produce any project. Designing and drawing the parts up is the most costly , (if had to pay for) you do 3D cad as good or better than most people.
Lay everything out and get another company with lasers to cut them out, you can get alot of projects cut long before you can own a larger unit. 
Maybe try a smaller import unit for all the small stuff.
Compare your 3D printer qualities, compared to what you get from Shapeways.
you hear what I am saying.
Dennis


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## denray (Jan 5, 2008)

My lasers all have air assist to help prevent fire, I can increase or decrease the airflow, I have cut alot of wood
on my unit, with very little issue. 
Dennis


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## toddalin (Jan 4, 2008)

Michael Glavin said:


> Todd
> 
> Does the laser have air or gas assist? This add on feature allows the user to process combustible materials, materials which produce combustible byproducts and helps mitigate smoke and enhances debris removal at the lasers path.
> 
> Michael




There is a hollow tube next to the turning mirror that jets air directly to the cut. You can watch the flame being "blown" as the material cuts. There are a series of fans along the back that suck up the smoke/fumes with a vent to the roof. If you open the lid, the laser stops cutting, but the pointer continues as the motors proceed.

Burning is worst along "outter" edges, as opposed to between adjacent cuts, because air circulates freely in those areas.


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## denray (Jan 5, 2008)

When a cut is made close to another line that has already been cut, the small or thin line of material between the two lines can get a lot hotter and maybe ignite from the extra heat. when the material is wider the heat is absorbed into the larger piece. One way to prevent that is to make the distance between the two lines wider, or you can go right back in the already cut line, now the laser is still running, but not cutting anything, produces much less heat. Many times when I have two pieces next to each other I will share the line so only one cut is made, it does require more setup time.
Dennis


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## Semper Vaporo (Jan 2, 2008)

What is the curf width? i.e.: If you share a cut line between two parts, how much is lost between them? Or, say you have a piece that is 1-inch wide and some number of inches long. How long would it have to be to cut four 1-inch squares from it (3 cuts)?


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## toddalin (Jan 4, 2008)

Semper Vaporo said:


> What is the curf width? i.e.: If you share a cut line between two parts, how much is lost between them? Or, say you have a piece that is 1-inch wide and some number of inches long. How long would it have to be to cut four 1-inch squares from it (3 cuts)?


I asked this same question of a regular user, and we are of the same mind. Unlike a mill where you remove material_ up to a certain line_, the laser cuts _at the center of the line_ so the loss is half the width of the beam, (give or take for the melting).

It really shouldn't matter if the material being cut is to be used or is waste, you loose this portion from both sides and compensate for it in the size of the piece.

The cut width is _very thin_, but is real.


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## denray (Jan 5, 2008)

When I laser something that I have to consider the Kerf, I figure .003 per line cut or .006 for a circle or square.
Occasionally we do figure kerf because of one piece fitting into another cut,
Dennis


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## Scott (Jan 29, 2008)

Awesome timing, I am looking into laser cutting and this has answered some of my questions.


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## toddalin (Jan 4, 2008)

denray said:


> When I laser something that I have to consider the Kerf, I figure .003 per line cut or .006 for a circle or square.
> Occasionally we do figure kerf because of one piece fitting into another cut,
> Dennis


Sounds about right for thin material. The thicker the material, the bigger the Kerf because you run the laser slower and more melts away, especially toward the top side. When I do thick pieces (3/8"), I "deep" focus the laser (just below the surface) and make two passes.

If you cut an ID and OD on a mill to the same size, they won't fit together because they will be too tight. Do it on the laser, they will be sloppy with fatter pieces being sloppier.


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## CliffyJ (Apr 29, 2009)

Thanks for the additional advice Todd. I really don't want any fires...! I like how you're engraving those (floor?) boards. I guess you have to leave the paper on while engraving(?) But is it a pain to get all the little pieces off?


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## CliffyJ (Apr 29, 2009)

Dennis, I sure appreciate your chiming in, I've long admired your work. I completely agree with the quality concerns over the Chinese units. But I need the larger work space, and the unit (installed) needs to fit within a $2,500 max budget, or there will be serious marital consequences. 

I appreciate your advice to get the cutting done by others. I haven't found anyone local to take it on though, after several searches. My mining structures alone will eventually involve around 16 4x8 sheets of acrylic, so that would be many thousands in cutting fees I'd expect (over several years). So, that's why I'm considering the lower-quality cutter.

Specifically, here's the one I have in mind. Is this one of the "commercial" Chinese units you refer to? I emailed them several of the questions I initially posted here, and will report back on their replies when I get them.

http://www.ebay.com/itm/291411058723

Thanks also for the tube comments. I need to ask the vendor what the estimated op life of the tube is.

Best regards,
Cliff


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## toddalin (Jan 4, 2008)

CliffyJ said:


> Thanks for the additional advice Todd. I really don't want any fires...! I like how you're engraving those (floor?) boards. I guess you have to leave the paper on while engraving(?) But is it a pain to get all the little pieces off?



I did the floor boards (and could have easily added nails), by setting the laser to full power at the maximum frequency, and running it at "100" the fastest speed, twice. The speed range is from 1 - 100.

Then in CorelDraw, _without touching the piece lying in the laser_, I remove the interior lines and run it at a regular cutting speed "8" to cut out the piece without cutting the interior lines all the way through.

You _want_ to leave the paper on if at all possible. This gives better cuts, especially along the bottom edge and protects the finish of the piece.


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## toddalin (Jan 4, 2008)

Are there any "Techshops" or "Urban Workshops" in your area?

I belong to the "Urban Workshop" and have access to complete metal shop (with lathe, mill, HAAS CNC), wood shop (with 4' x 8' CNC router), two laser cutters/etchers, 3D-printing, electronics labs, car workshop (5 lifts), welding shop, etc., etc. and pay $150/month for unlimited use.

"Techshops" are all around the country. For the cost of the laser, you could get lots of months, and they take care of the maintenance and miscellanous parts/stuff. You only need to supply your CAD file and materials.

I use a laser like this at the Urban Workshop in Newport next to the John Wayne Airport. It's 11 miles away from me.

BTW, the piece at the upper left corner of the laser cabinet (looks like a triangle/pointer) is a gauge used to set the focus of the beam. It magnetically attaches to the "cutting head" (seen inside the cabinet at the upper left) and you raise/lower the table so that you can just slide a sheet of paper between the piece being worked and this gauge with friction. Where the table sags, this spacing is increased and focus is lost to the deeper portion of the work.


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## CliffyJ (Apr 29, 2009)

Thanks Todd. I haven't seen any (after searching a few times), though that would be great.

I'll admit that I'd like to get started with my own machine, and eventually be able to produce parts / kits on my own.


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## riderdan (Jan 2, 2014)

I bought one of those cheap Chinese cutters on eBay. I've used it to cut a number of things, and here's some info you might want to consider:


It's very "Chinese"--there's no interlock on the door (you can open it and stick your hand in while the laser is running. Ask me how I know)
The bed size is very small. Realistically, you can cut about an 8x8 piece, at the largest. And the opening that you're "supposed" to use is about 4x6.
The drawing software is clearly a pirated version of Corel Draw. And the laser driver software is somewhat buggy. The speed controls don't seem to actually change head speed.
It needs a lot of upgrades to make it work "right"--The most important being air assist. You can 3D print one and run it off an aquarium air pump. Without this, smoke interferes and I got a lot of (small) fires
The optics are poor. If you cut an 8 inch line perpendicular to the laser head, you'll get more power at the "back" and less at the "front." This means some things will be cut through on one end but not on the other. You can work around this, but it's annoying.
It can take multiple passes to cut through thicker materials. The good news is that the stepper motors are pretty good, so a follow-on cut generally follows the first's route exactly. 
Overall, I've appreciated the chance to check out laser cutting on my own. 

I've cut some building walls (just the door and window openings) out of Sintra. 








Also the body of a little speeder 








I've cut some really thin plywood into snowflake shapes for Christmas coasters. I've cut out a couple of key-chain "labels" for my kids. And done a few other projects. I don't regret the purchase, though I haven't used it as much as I thought I would.
It works, and was probably worth the $300 I paid for it. But I certainly wouldn't pay more and if I wasn't so strapped for hobby money I would probably have saved up for a "real" used cutter from Epilog or one of the other big names.


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## Russell Miller (Jan 3, 2008)

riderdan said:


> I've cut some building walls (just the door and window openings) out of Sintra.
> Also the body of a little speeder


*DO NOT CUT SINTRA* on your LASER! Cutting any PVC, whether expanded type or solid, puts off acidic fumes that will destroy your LASER's optics. 

I manage the TAP Plastics store in San Leandro and we have three LASERS on the premises. Two are 1000 watt machines that have 4'x 8' beds and the other is an Epilog 35 watt unit we use mostly for engraving. We've been LASER cutting acrylic since the mid 1980's! I know because I've been with the company since 1980...

Stick with LASER cutting Acrylic. I prefer cast acrylic to extruded as it has less tendency to craze and crack near the LASER cut edge when it is glued. Cast also engraves better and melts less when cutting. In toddilin's photo he is using Cast Acrylic. You can tell by the paper masking with the red writing. Blue writing or polymasking usually denote extruded acrylic.

Besides acrylic, you can also LASER cut Styrene though you have to speed up the LASER quite a bit to reduce the melting. ABS can be cut also but it is very stinky and puts off an ugly smoke. Polycarbonate burns quite a bit on the edges, even the thin stuff so we no longer cut that. And we never, ever LASER cut PVC....

Russ Miller
TAP Plastics Manager
2016 NGRC Chairman


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## toddalin (Jan 4, 2008)

Another thing to consider.

When the laser is running it is almost hypnotic to watch, especially because you do need to keep an eye on it (e.g., fires). And run times are in the hours at best for many pieces.

The glass cover on the Epilog is treated so you can look at the beam without burning your retinas,  though it is not suggested.

I would be sure that any machine that I purchased was so equipped.


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## CliffyJ (Apr 29, 2009)

Thanks Todd, I included that in my next batch of questions.

They did answer my first round quickly, and here's the responses in all their glory.


Dear sunshinesmileservice, [that kills me... I can't believe I'm contemplating a vendor with that name... ]

Hi, I'm interested in this product, but have questions. 

Support: Can you describe how I would get technical support? And what is covered in the 3 year warranty? 

It has 3 years warranty, if it has problem, you contact me for help. Don’t worry; you are strictly protected by PayPal. And the order process is exactly same as eBay. (the three year warranty is NOT only a ebay warranty, we provide it to all my customers who making payment directly via PayPal as well, they are still under PayPal protection, It means that PayPal will refund the money to the buyer if we are unable to provide with warranty. I have to stress here: our item is excellent quality, at least we have NOT yet get any problem from this item)​
Functionality: This will perform both engraving, and cutting, correct? What thickness of acrylic or wood will it cut? 

Yes it perform both engraving, and cutting, 0-4mm thickness of acrylic and 0-6mm wood will it cut.​
Motorized up / down (vs manual): What's the purpose? And if it is important, how can I obtain it? 

Motorized up / down, the machine has two switches can control it up and down to adjust the distance between the laser head and the mateial.​
Sheet size: You mention 700x500mm. Is this the max size of material? Or can the laser actually cut to this? 

700x500mm is the working table size, the max size of material.​
Can I also obtain the rotary attachment?

It doesn't come with rotary attachment, if you want, it is 180USD per unit.​
Shipping comments:

My offer includes the shipping. And tracking # would still be updated to you asap.
Once we receive your payment, we will send out the package from USA warehouse on the same day or within one business day. Estimated Delivery is 5-6 business days. Also if you need the liftgate service, it is 75USD.​
What is the operational life of the laser tube?

It is about 3000-3500 hours...​
Do you provide replacement tubes? And how much do they cost?

...and we also replacement tubes, it is about 250USD per unit.​​


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## toddalin (Jan 4, 2008)

CliffyJ said:


> Thanks Todd, I included that in my next batch of questions.
> 
> 
> 
> ...


4 mm only allows for 1/8" thick acrylic material. 

3/16" = 4.76 mm and 1/4" = 6.25 mm though the actual acrylic is a bit under these dimension.


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## CliffyJ (Apr 29, 2009)

Yeah, I saw that, weird. I think they're parroting the sales lit covering other / smaller units. This is for a 60w system, so should be fine for 1/4" acrylic.


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## dbodnar (Jan 2, 2008)

CliffyJ said:


> Yeah, I saw that, weird. I think they're parroting the sales lit covering other / smaller units. This is for a 60w system, so should be fine for 1/4" acrylic.


Cliff - FYI, I have no difficulty cutting 1/4 acrylic on my laser cutter. 
The photo is of a case I made for some DCC equipment I designed and part of it is made up of 1/4" acrylic. The only issue you get into with thicker material is that the edge may not be 100% square as the focus point can be a bit above or below the center of the material.

dave


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## CliffyJ (Apr 29, 2009)

That is a really cool case design you have going on, Dave. 


BTW, here's the responses to my latest round of questions, received sometime last night.


1. When I order replacement parts, do you stock them in the US? Or do they come all the way from China?
the spare parts are available in the USA now.
http://www.ebay.com/itm/60W-Sealed-...2-Laser-Engraver-Cutter-Machine-/112249519985
http://www.ebay.com/itm/Axis-360-Cy...-60W-80W-100W-Engraving-Machine-/111703592749​ 
2. Do you have a referral or two, that I can ask about their experience with this item?
[no response]​ 
3. Does the top window have protective film, to prevent eye injury?
I confirm the top window have protective film.​ 
4. For this 60watt unit, is the laser tube truly rated at 60 watt, or 50? Several people say that the tubes have less rating than the power supply, and warn never to run the system at 100%. Can you comment on that please?
the laser tube has 55-58 power because it has power lost etc. [I'm skeptical]​ 
5. Should I buy an 80watt tube with the 60watt power supply, to make sure the tube lasts as long as possible? (I'd rather not do that! But I was encouraged to ask).
the machine only work with 60w power supply. [not what I asked...]​ 
6. I've been advised to install a milliamp meter, if not present. Does the system already have one though?
[no response]​ 
Cheers,
Cliff


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