Earlier this year, I bought one of those K40-style laser machines that was listed at a ridiculously low price, and it arrived broken. Well, let me qualify that: the laser tube and the power supply work perfectly, but that’s about the best you can say about it.
On first power-up, it made a horrible noise, the Y-axis was jammed, the X-axis was so off-square that it was visibly apparent, and it turned out that as I fixed one of these problems after the other, that it was just the tip of the iceberg. The Y-axis was jammed because the belts were so tight that they made the motor bind. Replacing them, because they were simply too short, got the stage moving, but it didn’t engage the endstops. Fixing those revealed that the motor was stepped wrong, and flipping the pins in the connector finally got it homing in the right direction. Full disassembly and reassembly steps required at each stage here.
The X-axis just needed adjustment, but the opto on its endstop had been completely crushed by a previous failed homing, and I had to desolder and resolder in a new one. (Keep your junkbox well stocked!) With the machine working, it became obvious that the driver board was barely usable. It accelerates horribly jerkily, which makes the motors skip and stall. It had to be run artificially slowly because it couldn’t make the corners. So I put in a new motor controller board that handles Gcode and does legitimate acceleration ramps.
Movement mostly fixed, it was time to align the laser. Of course, the optical path is all messed up, they forgot the o-ring that holds the focusing lens in place, and the thing keeps powering down randomly. This turns out to be because of the aiming red laser pointer, which has a positive case, which is shorting through the single wrap of electrical tape that “insulates” it from the machine’s frame. When this shorts, the motor driver board browns out. Lovely!
Once I was finally able to start aligning the beam, I discovered that the frame is warped out of plane. The simple solution is to take it all apart again and shim it until it’s flat, but I just haven’t had the time yet. I’m not beaten, but it’s been eating up hours after hours on the weekends, and that time is scarce.
I love DIY, and I love taking a machine apart in order to understand it. Once. But I’m now on my tenth or twelfth unmounting of the motion stage, and frankly, it’s no fun any more. It would have been quicker, if maybe not cheaper, to have built this machine entirely from scratch. At least for the moment, I’ve bitten off more than I have time to chew.
You get what you pay for and the only winner here is Mr. Sum Ting Wong who made a buck on a stupid laowai.
My K40 is also from China, obviously, and worked perfectly out of the box, didn’t even have to align it. Over the years, I replaced the stock bed with a honeycomb and played around with adding an air-assist, but those are more upgrades than repairs. The biggest problem it had was when the inside got a leak due to excessive pressure on the cooling water when I installed central cooling water in my shop (the Chinese engineers do love their water cooling), which I fixed with an appropriate pressure regulator and a zip tie for good measure. It worked fine after drying out (I gave it a day after removing visible water to be on the safe side.)
The amount of racism on Hackaday is incredible, and the fact it is so tolerated is disappointing.
Something goes wrong and you immediately set up a racial strawman to blame. The author never said they bought it from an Asian person so why do you immediately reach for a racial slur for Asian people? Would Hackaday be okay with blaming Mr. Jacob Goldstien or Mr. Tyrone Freeman or Mr. Raul Sanchez?
Assuming a dishonest seller must be of a specific race is pretty messed up.
I’m actually fine with the jokes about Mr. Goldstein, Freeman, and Sanchez as well, as long as they aren’t too mean. It’s not a big deal. The neurosis of entirely non-offensive life is not worth the benefit
K40s come from China dude.
These days many things I buy I expect to have to fix. I bought a really nice portable air compressor only to find out that the battery life was about 8 minutes. What’s worse was the standby life was only like a day. So every time I picked it up to use it it was completely dead.
Tear the battery pack apart, replace the cells with nice high capacity cells and the thing is great!
I have at least one old XYZ assembly (ne Lulzbot but died of bad firmware update) that I keep just for this kind of eventuality – one day I’ll need a good solid assembly to fix some other bad investment :-)
Consumers as beta testers.
Bananenprodukt. Reift beim Kunden.
(Banana product. Matures at the customer.)
Being in the US, I am going to miss cheap Chinese industrial machinery more than anything else, I think. It’s a great value for the money, and more and more, it just works fine out of the box. The average quality has gone markedly up over the last ten years. I still take the covers off and do an inspection of it, though, to be on the safe side (and try to get a feel for what might break in the future.)
If you’re old enough (not even that old) you remember when we had all that at a cheap price without having to ship everything across oceans. It’s just not viable long-term, for a huge variety of reasons. People will try and justify it, say I’m wrong, but that’s just the language of junkies trying to rationalize another fix. They’ll say anything
Don’t worry. It’s all coming back. Together with polio and rickets. You won!
Hooray! I hope you get both! You still don’t understand how much the entire world is angry with you, you don’t get it–you’re in danger!
I’m not that old, so I enjoy cheap Chinese tech. It is what it is. I’m not a politician, worrying about geopolitics isn’t my job.
It is what it is until it changes. It will change again, that is a constant.
Maybe they had to get it out the door and on the ship before the next round of tariffs were imposed.
The one I purchased 10 years ago surprisingly worked out of the box. I say surprisingly because even the mirror alignment was on target enough that it was only out less than 1 mm in the opposite corner from the homing switches. Mechanical switches, analog system with mA meter and power adjusting POT.
If you look around you will find there is no one K40 manufacturer, it’s just a design target and model name.
Usually the only common component is the m2nano controller(now m3nano) and the laser power supply.
They also come with low grade 35W laser tubes so if you run them at over 18mA you will wear the tube out quickly. When you get a real 40W tube then it feels like a new more powerful machine being able to use full 40W of power.
Bad quality control doesn’t mean that there are no good units, it means there’s a lack of consistency. A lot of the time it’ll be fine, but people do get duds.
Totally on-par with my k40 experience(s). I’ve updated two of them to slightly-more-usable condition over the years. Plan on a lot of learning and work before it will “just work”. The power supplies and tubes don’t last long. And the mechanics are shit. But it might be worth it if you want to up your laser and CNC game on your own timeframe.
i have doubts about alaska’s shipping companies ability to get stuff here in one piece. i swear there is a ten story drop on some of their conveyor belts at anchorage international. they trash anything over ten pounds. not so bad if they route it through one of the ports down south. been wanting a k40 or similar for years, but i think its physically impossible to arrive in one piece.
You mean they don’t just throw your mail out of an old Cessna as it flies over your general location? I thought that was how it worked in Alaska :)
I bought a K40. I read up, I figured out how I could make it nicer, spent a ton of money on upgrades, and hit a point where I realized, for all of the pending work, and money, I should build a bigger machine. I found myself demotivated by what the small work envelope would be, and put off by the idea of more money for X/Y components, higher wattage laser and PS, and… a big laser-safe cabinet. I realized I’d basically end up throwing away the last bits of the K40 I bought. The whole project stalled.
Then I bought a Creality Falcon 2 Pro 40w. I added a honeycomb bed, a crosshair led laser, and rebuilt / reworked the exhaust with 3″ to 4″ pipe adapter, rigid alu 4″ pipe, 6″ exhaust fan, and an exit box for the fan, to pull while the internal fan pushes. And I’m happy, very happy, with this machine. It’s LED, not CO2, but has no water cooling system, no mirrors to align, takes up less overall space, has a much larger work area, camera, pull out drawer, etc, and works very well.
Maybe one day I’ll revisit the K40 disaster, like when I really want to do nice work with acrylic, but not today.
That these come through at all is an astonishing thing – I have had some run-ins with customs over getting a diode laser for the lab (four whole watts!) and it can get byzantine in a hurry. Now a “40 Watt IR laser” is a commodity item and FO laser welders claiming preposterous wattages even have a pistol grip though I’m not sure if they’ll stay collimated for long distances.
In general, the equipment coming from the Far East is following a predictable path, tending toward upscale quality seeking to establish their brand, or low price copies of existing items with a rough finish and a lot of hilarious marketing bloviation. If you dig far enough back you’ll find “Made in Japan” as a derogatory comment about bad copies or shoddy tooling, which is in league with current “Chinesium” comments. Simple industrial production machinery leads this by some years and much of it is very good at this point.
The next step after the bad products fail and the few quality brands capture consumers’ trust is general “value engineering”/enshittification that creates market space for new brands (and possibly whole countries) to fill in the gaps.