The K40 lasers are legendary for their poor quality and unreliable components, but as far as I can tell those might be issues of the past. I’ve been getting excellent results—here’s what’s it took to get there.

The Backstory

It seems about twice a year, the web is flooded with CHEAP Chinese-made laser cutters. Sites like eBay, Alibaba, Amazon become host to sub $400 machines that are capable of cutting wood, acrylic, fabric, leather, etc.

After seeing an Inventables thread talking about a particular $366 40W CO2 laser cutter (which included several good reviews), I made the impulse decision to dive in, buy one, and try it out.

I must have been under a rock, because I didn’t realize how dramatically they’ve come down in costs, especially considering how the components appear to have improved dramatically versus what I’ve seen on some other blogs.

For years, it was possible to spend lots of money on a machine that barely worked. Now, it’s possible to start with a $366 machine, add a few hundred dollars of mostly-optional upgrades, and end up a super reliable machine.

UPDATE, NOV. 2018 I’ve used the machine for almost three years and made hundreds of things. It’s working as well as ever—which I sometimes write about under K40 Laser Projects.

I’ve used the machine for almost three years and made hundreds of things. It’s working as well as ever—which I sometimes write about under Acrylic

I detail the process below, but in short:

$366 bought the unit,

+ $175 of extras to improve usability

+ 12 hours of tinkering to start getting predictable results.

Unboxing & First Look

The box arrived in three days (two days earlier than promised) and the double-walled boxes did a good job keeping everything intact.

The unit surprised me with its size (banana for scale).

What $366 Bought Me

For its low price tag, it’s impressive that it arrives with almost everything you need, minus a bucket. Most of the items feel disposable (and they are) but are at least good enough to get up & running.

The accessories are CRAZY CHEAP, but the main parts will work just fine.





ITEM CONDITION THOUGHTS Laser Cutter Very Good It arrived with few small surface dents in mystifying parts of the enclosure. One door had to be bent back into square but was an easy fix. Water Pump Seems Reliable Common water pump like you’d find in a fountain or aquarium. Came with a European-style AC plug and adapter. Blower Bad Don’t be fooled, this is a bathroom vent. That helps explain why it doesn’t fit the machine. It’s just good enough to get started, but replacing it is a high priority. Vent Hose Very Bad Here too, don’t be fooled. This isn’t a vent hose, it’s a down-spout tube, like you might attach to rain gutters. The plastic is flimsy, and I threw it away immediately. Software DVD+R/Dongle Surprisingly Usable The burned DVD+R included a maybe-bootlegged copy of Corel, plus English and Chinese copies of the plugin that lets Corel talk to the laser controller. The serial number came in a .TXT file—seems legit. /s Tape & Sealant Useless These parts are ostensibly included to seal the water tubing and air vent. I’m sure you’ll find a better solution. User’s Manual Bag Useless The cherry on top—it came with a user’s manual bag for a product with no manual.

Extra (& Optional) Items

These next few pieces were mostly optional, but for the extra $175 I spent, I was able to put together a compact, reliable system that *should* pave the way for an easier time learning the ins/outs of the tool.

I should mention— I set up my laser in an unused shower. It takes advantage of otherwise useless space, and the area already has durable surfaces, good ventilation and access to water.





ITEM COST SOURCE/NOTES Computer $45 Refurbished Dell Optiplex 760 / 2.66gHz Core 2 Duo / Windows 7 from local tech recycler Wire Shelf $45 Amazon.com | The adjustable legs were useful in placing the machine in the space. Water Basin $8 Amazon.com | Common 28-quart “Rubbermaid” bin; mine comfortably held about 3.5 gallons of water. Air Pump $35 Amazon.com | This thing is appropriately powerful; the included manifold makes air control easy. Air Tubing $3.39 Amazon.com | Super standard aquarium air tubing. Upgraded Aluminum Vent Hose $8 From the local Hardware Store — The same stuff you’d use for a dryer vent. Be sure to choose metal over PVC if you have the option. Fire Extingusher $46 Amazon.com | …because it’s important to not be a dummy. Smoke Detector $14 Amazon.com | Only *you* can prevent laser fires! Air Assist Nozzle $21.14 via LightObject Send me an email if you want a free air-assist head! This one is advertised as “Ideal for K40 machine”, but I didn’t double-check my dimensions and this 18mm part didn’t fit the 12mm aperture on my machine. ):

Full Disclosure

The Electronics & Guts

This page links to products I’ve bought at full price & use myself. Buying from a link on this page earns me a few pennies to help pay for my cheap-and-completely-okay web hosting



The electronics on this one are impressive—with solid terminations, uniform solders, clean cable management etc. There’s also plenty of space in the enclosure for eventual upgrades—vent/air relays, lighting and other accessories.

Controller Board Lihuiyu Studio M2 Nano Software Corel Draw v. XX w/ Corel Laser

Overall Quality

Aside from the few dents in the enclosure, the build and electronic quality seem reliable. There are no obvious areas of workmanship that seem deficient.

There was water in the silicone tubing, suggesting that at least some testing had taken place.

Laser Alignment

All-in, I spent about 3.5 hours aligning the lasers. There are a ton of great resources across the web on k40 alignment, but after reading thru several, I found that tinkering around and making a TON of small adjustments was the only route to success.

The lens was confusingly dirty, but a quick rub with acetone cleaned it up almost instantly.

The logic is pretty intuitive: starting at the tube and working toward the lens, align the beam to the center of the mirrors. Less obvious to me was that it also might require adjusting the position of the actual tube.

Focusing Order

0. Align & shim the laser tube (hopefully not needed, but well-documented elsewhere.).

1. Align each mirror until laser hits center of the mirror.

— First stage is immediately in front of laser tube, under the rear hood.

— Second stage is fixed to on the left side of the Y-gantry.

— Third stage is fixed to the X-carriage, redirecting the beam to the collimating lens.

2. If you detect unexpected reflections and can’t hit the center of a mirror, you may have a mis-aligned laser tube and need to return to step 0.

[Dummy Check] Be sure that the flat side of the lens is facing down .

Repeat after me— Flat side of lens faces down. Flat. Down.

Bullseye

Right in the middle—looking good.



First Etch/Engrave

Customary first quote— This one was 15mA at 25mm/s on leather.

Final Thoughts

For around $550 all in, this is a solid BUY* in my book.

*It took about 12 hours of total setup and learning before I produced any meaningful result. But after a few failed tests in acrylic, I was off and running, cutting fast and accurate parts.

This is NOT an out-of-the-box solution, and it really does require that you spend time understanding the components and their optimization.

I also had several advantages going into this process that allowed me to get up and running fast—previous familiarity from the X-Carve CNC and fluency in graphic design workflows were the most beneficial in getting it running.

First Cut

For my first magic trick, I designed an acrylic enclosure in Adobe Illustrator, exported to an .SVG, and sent it into CorelLaser (CorelDraw) to run the job.

I’ve posted a more detailed entry here, but in short: it turned out AWESOMELY.

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