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30 October 2018
Category: Ecobion Labs News
Posted by: Ecobion Labs

We have use of a HUGE garage for continuing our restoration work on the GMC.

14 July 2017
Category: Lab Blog
Posted by: Ecobion Labs

A bit of tidying up with new Repairs and Weekends Projects Categories making it easier to find things.

21 June 2017
Category: Lab Blog
Posted by: Ecobion Labs

We've just received our new JGAURORA Prusa i3 3D printer!

 

K40 Chinese Laser - Extractor Fan Issues

So, we first encountered the extractor fan in the unboxing, and it doesn't work that well. In fact, it's a bit of a waste of space. A bit harsh?

Firstly, something that came to light in a YouTube video from ECProjects (it was actually his video that convinced us to get the laser) where he shows some very dodgy wiring in the fan. It seemed too unbelievable, so I checked mine, and at fist glance, the wires seemed ok...

K40 Laser fan wiring seems ok at first glance, but it isn't!

... until I slid back the sleeving covering the wire joins! Different to his, mine had a touch of solder, but the wire stands already were broken (I think they used teeth as wire strippers), and they didn't even try to follow any wire colour convention - although I suppose with a non-polarised 2 pin plug, why bother? I would conclude that the fan is slightly safe if you didn't pull at the mains cable, but would you want to risk this?

K40 Laser demon wiring revealed

The worrying part was that I could just pull one of the joints apart reasonably easily. So, a repair was efectively needed: I cut off the ends, stripped them with a proper wire stripper, and lightly tinned the tips.

K40 Laser Tin the tips of the stripped wired to make a twisted joint easier

Overlapping the wires making an X shape, I then twisted them around each other, which gives some mechanical strength to the joint. This was then reflowed with extra solder to fuse the wires together, and the heat shrink slid over and heated up with my hot air gun (some people use a gas lighter) to shrink into place, and just for authenticity, the original sleeving was slid back over the heat shrink.

K40 Laser Heatshrink over soldered joint

This was applied to all three of the wire joints. With the third joint, twist two wires side by side, then add the third wire as described above. Make sure your heat shrink is on the correct cable when you slide it along - I made this mistake and needed to remake the joint again! DOH! Almost as bad as forgotting to slide it onto the wire BEFORE you start soldering. With all that done, fight to tuck the wires back in and replace the cover!

K40 Laser Tucking wires back in

For the record (as an after-thought), I did replace the plug. Wiring doesn't seem to matter, but as the condenser in the unit was attached to the orange wire, I thought it would be best to make this live, with black becoming neutral. The wire was so thin that the strain relief couldn't grip it, so I had to pad it out with some cable outer insulation to allow sufficient squeeze. 3 amp fuse fitted in the plug.

K40 Laser new UK plug fitted with unconventional wiring colours

With the fan made safe, it was slid into the slot at the back of the laser, with a noticable air gap. Some additional foam will be needed to seal this area, but for now some masking tape is doing the job. When the system gets a decent upgrade, this fan may be discarded, and replaced with a simple ducting adaptor, but for now, it works - Sort of, but not all that well.

External Links:

YouTube 40W Chinese Laser Cutter: Review, Setup, Use - Ec-Projects:
https://www.youtube.com/watch?v=KhhOHUe_b6o

Facebook Chinese K40 Laser Group (group member approval required): https://www.facebook.com/groups/888394261237059/

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