K40 Laser Cutter – the cheap Chinese hobby laser cutter

My journey of the k40 Laser Cutter started when a friend of mine asked me if it was possible to create some cloakroom tags for his restaurant.  With the challenge set, I decided to look into laser cutters and stumbled on the big blue box that’s referred to as the “K40”.

Although at the time I knew very little about laser cutters or laser cutting in general, a quick google search led me to eBay and also to a  sea of blue and white lidded boxes with a monster of a 40w laser inside.

Now monster may not be the right word, but it is compared to the 1mw laser pointer I bought on eBay years ago, the laser industry has progressed a lot more than what I knew it ever was.

To put things into perspective, you would need 40,000 1mw laser pointers to generate the same max output as a k40 laser on full power setting. So it really is a monster of a machine when you look at it like that.

After browsing eBay for about a week I considered buying the smaller 5w desktop lasers but decided against it because of the small engrave deck, as well as the actual finish quality of the engraved piece. There was a substantially less resolution on the cheaper USB desktop lasers.

There were also a few of the more expensive laser cutters in the range of $3000 that  I considered, but as I am a hobbyist as of now I decided to go with the K40 Laser Cutter. My package came in a little over 7 days and was intact and packaged well.

Everything that was promised on the listing came in the box. Included in the box was the K40 laser, fan, water cooler, instruction manual and tool bag.

There is not much information in the way of actually operating the K40 Laser, so after a few days of procrastinating I fired it up for a test cut. I watched a few videos on youtube to get the basic setup going and create a text file within Inkscape to test out the output quality of text within the K40.

After a week of trial and error, I started to make some progress of getting the quality to where I was happy enough to give it as a final product.

The thing is with the K40 Laser Cutter, is that it has a narrow range focal point of approximately 10mm, which means any material that sits higher or lower than this will tend to blur when engraving and won’t be as crisp as the K40 is meant to be.

I currently use K40 whisperer, which is a great little light-weight tool which apparently is better than the infamous standard software that comes with the K40. It comes as freeware and setup takes under 10 minutes to complete.

There is a spring-loaded base deck which I assume is designed to hold the material you are cutting. Although it holds the material very well there are a few problems with this

1. There is no reference to the focal point when the product is fastened in the engraving deck.
2. When the material is fastened in the engraving deck it’s 0,0 reference point is not 0,0 with the machine it’s about -28x, 24y. I decided to take the deck out to clear up some much-needed room and to also re-calibrate where the 0,0 point on the laser was, so I didn’t have to work out what the actual 0,0 of the material was every time I put something in the machine.

First of all, I created a makeshift plane to hold the base material, which I then use the vector engrave function within Whisperer to mark out a small x and y-axis.

Secondly, I used a test file to find the optimal focal point and chocked up the material so it was within the focal point range I calibrated

Generally speaking, 100mm/s is the speed I aim for –  which takes into consideration the need for a fast engraving as well as an accurate engraving.

The faster the speed of the laser, the more power you will need to output, therefore the longevity of the K40 Laser Cutter will decrease

Overall the K40 Laser Cutter does a great job. As I haven’t owned a laser before or used any kind of CNC Machine, I was very surprised at the quality for a relatively cheap machine.

If you are ready to dive into the world of laser engraving, you can follow the link below to the same machine and supplier I used.

All the best on your engraving journey, Sam