Demystify cheap EBAY laser cutters?

I've used my fair share of nice name brand lasers as well as cheap so-Chinese-they-don't-have-a-name-brand lasers. They're all a little different. The Chinese ones usually come with their own crappy software and there usually isn't an alternative other than possibly using Corel Draw. Usually what you have to do is design in different software and figure out what format is ideal(usually .dxf) to save as and import your design file into the crappy software to send it to the laser. [This can be a serious pain as different design elements can export and import differently. Our laser uses .dxf or Illustrator 8 files, but still inconsistently.]

No matter what they tell you, all lasers needs some sort of ventilation. So assume you'll need to set up a fan and duct system and cut a whole in an exterior wall. I've never tested it, but it might be possible to use a very fine filter to avoid exhausting outside, though I've never seen this done successfully.

The cheap lasers will have an advertised wattage, but sometimes they don't actually operate at that power. Our hackerspace 50w laser only operates at 32w with a new tube. The power level of the tube determines how thick of material you will be able to cut through.

To help your laser last longer,

• Carefully clean the mirrors and lenses regularly.
• Don't run your laser at full power. Keep it to 80-90% as it should lengthen the life of your laser tube.
• To extend the life of your servo motors, mind your speed when etching. The laser head travels back and forth quickly having to ramp up and slow down at either end. If you're etching a small area, you may want to decrease your speed so that the rapid start and stop motion of the servos doesn't wear on them as much.

Lasers are hackable, or you can buy a kit and build one from scratch. I just visited Dallas Makerspace and they have a laser with a decent sized bed that was built from scratch.

Something to consider, the focus range of a laser is quite small so the axis need to be very level and very square. If they are not, you will get uneven cuts or areas that will simply not cut through. The focus area of a weak(<60w) laser can be less than 1/4". When building a DIY unit, it is very easy to have the height difference of your axis be off that small amount.

Laser cheat: If you have a weaker laser and want to cut through material thicker than what your laser can handle, sometimes you can refocus the z-axis so that it is not focused to the top of your material as you would normally focus, but raise the z-axis so that the laser is focused on the center of the material. You'd have to eyeball this typically, but I've had it work often for me. This is typically done on a second pass. This technique may yield a larger kerf.

Note: If a laser says it can cut through 1/4" material, that doesn't always mean ANY 1/4" material. Solid lumber is easier to cut through than plywood because plywood contains glue, which is harder to cut through. Likewise, MDF or hardboard can be harder to cut through because it also contains glue. So if you can cut through 1/4" bass wood, you may not be able to cut through 1/4" MDF.

If you have other laser questions, I'd be happy to help!

theheckwithkaren wrote:

 

 

No matter what they tell you, all lasers needs some sort of ventilation. So assume you'll need to set up a fan and duct system and cut a whole in an exterior wall. I've never tested it, but it might be possible to use a very fine filter to avoid exhausting outside, though I've never seen this done successfully.

 

I've used a LaserPro Spirit GE laser cutter with a filter box and it was surprisingly effective.

I think it was a Bofa AD 400TS extractor/filter unit.

Laser Extraction - Laser Cutters - CAD/CAM

Filters | Laser Fume Purification | BOFA International

Thanks for the response! Something I'm really curious if you know how these lasers are "driven". I know that, for example, my 3D printer uses GCODE that's sent serially (ok, USB but acting as a serial connection), but I'm curious if there's any info out there about how these lasers are typically driven. My suspicion is that they're driven like a printer - so something like a printer driver is actually handling the communication. So it'd be proprietary, and short of decompiling the driver or otherwise reverse engineering the protocol, there probably isn't much out there.

Anyway, thanks again for the response!

Oh, and just because I'm dying of curiosity, is this THE Karen from TBHS? Cause if so, that's AWESOME.

The likes of the Spirit GE uses a printer driver. It's actually more like a pen plotter driver as it uses the different 'pens' to do different types of cut allowing you to set different speed and power for cutting versus engraving operations. If you draw the design in Corel Draw then you use different line colours to denote the different types of cut you want which are then defined in the printer driver.

The likes of the laser upgrade:

https://www.coolcomponents.co.uk/laser-engraver-upgrade-pack-500mw-for-xy-plotter-robot-kit-v2-0.html

for the X-Y plotter:

https://www.coolcomponents.co.uk/xy-plotter-robot-kit-v2-0.html

appears to be able to use G-Code however.

A lot of the lasers I've seen use software that is setup like a printer driver. I'm not extremely knowledgable about computer hardware/software, so I can't help much more than that.

Dave is correct, with all the lasers I've used, you can set vectors(lines) to different colors that allow you to apply custom speed, power, and etch/cut settings to each color. But if you're going to run layers at different settings all in one "print" make sure you test a small area of whatever material will be used for the final product with each setting first to ensure you get the desired results before you spend the time and material to do the full job.

And yes, I'm the real me. *waves*

Phillip,

To be honest I always search for a cheap product by - maybe a prejudice - I don't search o ebay. Recently I had sponsored by GearBest for a bunch of things in support to the PiIoT kit from Element14 for the challenge. Together with a hundred of steppers they sent me too a 2.5 A laser engraver/cutter.  I have already published the instructable GearBest laser engraver DIY Kit assembly instructions  on how to assemble and setup it and to be honest it is cheaper than the range of 500-600 $ but it is - in its simplicity - very well done. I confirm that the laser has itw own cooler fan controlled by the board.No way to have it working for a long time without. For detailed usage of the laser engraver / cutter (this is not super-power but you can consider is as a good example respecting the fundamental principles of this kind of tools) you can follow the further posts on the PiIoT Challenge.

Enrico

Again. I try to answer to your second part of the questions, the software. The laser engravers, as well as the 3D printer, CNC machined etc. are managed by a micro controller board that accept in its firmware a g-code dialect. I mean dialect because in this particular case of CAD tools there are some specific commands typical of the laser control. First of all there is no x axis that is replaced by the laser lens focus. Then there are commands to control the laser continuously or by pulse, depending on the depth and the kind of job you are doing, the material etc. Then there are G-code controls like the laser to very-low-power for positioning, laser fan activation etc.

So there is not a single software you can use and the format, DXF instead of SVG, AI or other vectorial file formats or bitmap images (jpeg, png, bmp) in the case you need to make a variable depth engraving, using greyscale images or pure monochrome - black and white -

What you need is a software able to manage these kind of files, give you a good quality resulting image in g-code format to export it and send to the machine. I suggest software like Artcam if you are doing mostly graphic elements but Inskcape or Gimp (both are open source and work very well on all the platforms) are also a good alternative.

So there are two different software level:

• The graphic processing of the image
• The machine control software.

Currently I am using Brenbox for the machine control but it is almost crap and is a temporary solution. The graphic objects are created with the mentioned programs and other (including Rhino 4, Phtoshop CS5 etc.) then the export formats are those mentioned above.

An approach that I consider interesting is a project I am working on where you can control the machine with a Raspberry PI and a java application. It acts as a server that can be accessed by the network directly from your pc from where you export the original image in G-Code format.

To do this I am making a porting / hacking of the universal g-code sender almost oriented to control laser machines.

Enrico

Wow...now THAT might be exactly what I'm looking for.

In a general way - I wasn't really just thinking of Ebay as a place to look. It just seems like there are a LOT of the same model of laser cutter/engraver running around that is sourced from China. Ebay happens to be the cheapest (from what I can see) source of such things.

That being said, this kit looks AWESOME. Also, it looks very "hackable" in the sense that increasing the dimensions of the cuttable/engraveable area is largely a matter of getting longer rails. I'm guessing that if it was to get TOO big, the steppers would need to be upgraded with larger/stronger motors - which would probably mean increasing the power supply to those steppers. But anyway.

Definitely going to look more at this one...you may have found the winner!

OMG OMG OMG (ok, kidding). Anyway, thanks for the great info and great show!

Oh and are you guys going to be at Makerfair in Detroit at all?