Chinese Laser Engraver/Cutter

[t5956ws]

Hello all. Last February I started a scratch build project. My second. It's the South Carolina/L'Indian circa 1777-1781 as pictured in "The History of The American Sailing Navy" Chapelle.  It's quite a project for my skill level. There is much repetitive detailing on this ship that I have little skill for.

 

Anyway, with that in mind I started to gain interest in laser cutting. Hoping that it may solve this problem. On E-Bay I discovered the one flooding that site for around $370 USD. I U-Tube'ed it to death and was quite satisfied with what I saw. I have NO CAD skills but what I saw at $370 was worth the challenge.  At this point I am delighted I bought it. I'll briefly share with you my initial experience.

 

The unit is a 40w CO2 laser cutter. It is quite large and weights 67 lbs.  It took me about 5 days to set up, test and operate. I have attached a photo of my early results. The two attachments are Bitmaps I created using the computer's "Paint Shop" tool to drive the laser.

 

In the photo are the parts for a gun carriage cut from 1/16" basswood. These piece I did not separate so I could show the detail. The other part is a decorative wales detail is cut from 1/2mm cherry veneer .

 

 

For more detailed info on how it runs or specs, that can be found on U-Tube. There are at least 20

Edited January 3, 2016 by t5956ws

[mtaylor]

To fix the title, just click "edit" on your first post and "more options" on the lower right had side.

[Bob Blarney]

Hmm, that looks interesting.  How fine a line can the laser cut?  I suppose that it has a fixed focal length, and so there would be an optimal distance for focusing the beam.  Are there adjustments to place the material there?  

 

Also, I would imagine that the fineness of the cut may be somewhat dependent on the power of the beam. (Forty watts of laser energy is actually quite powerful.)  I have aiming lasers on my drillpress, and at first they weren't very useful.  Then I noticed that as the 9V battery weakened and the lasers fainter, then also the projected laser lines became finer.  So I substituted a variable voltage 'wall-wart' adapter so that I can adjust the brightness of the beam, and eliminate the battery as well.

Edited January 3, 2016 by Bob Blarney

[t5956ws]

I believe the actual beam is about but <1mm.  As for focus distance, there are different lens. Stock is a 12mm lens with a 50.8mm focus. There are aftermarket lens that are 35mm. I have not fooled with adjustments yet. If there are not, I'll use spacers in the lens mount or on the work piece bed.

 

There are three upgrades I intend to execute. #1 is air assist. That will keep smoke and debris off of the beam and cool the part quicker. #2 a water flow indicator to protect the tube. The tube is water cooled. #3 A cabinet light. I found a 13" LED that will attach with a double sided tape in the cabinet.

 

My use for this is repetitive accuracy.  All in all, for the price, I'm well pleased.

[mtaylor]

Definitely get the air-assist.  It will help prevent flare-ups.   As a laser cutter owner/user, here's some other tips..

 

1) Check the lens.  The Chinese have a habit of putting them in upside down.  The curved part of the lens goes "up" towards the mirror, not down towards the material to be cut.

 

2) Keep a water spray bottle and a fire extinquisher handy.  And NEVER walk away and let the unit cut or engrave un-attended.  There's a lot of horror stories where the cutting material catches fire and the operator returns to find the area in flames.

 

3) Definitely set the focus.  And also check that everything is square to the z-table.  Shim/adjust as needed so that your focus doesn't vary from side to side and front to back.

 

4) If you haven't, align the mirrors.   The beam should hit each mirror dead center.  Here's a good link on these units.. and he has excellent alignment procedures:  http://dck40.blogspot.com

 

5) Most importantly, have fun.  But be safe, especially when cutting.  Make sure the lid is closed.

[Bob Blarney]

I haven't see this thing yet, but I'm imagining how useful accessories might be made in the shop, instead of bought.

 

Air assist might be accomplished with a fan, an aquarium pump, or a compressor.   The water coolant might be supplied by an aquarium pump arrangement, or a slow-drip gravity feed.

 

In my basement shop, I have heat detectors conntected to a central alarm system, and not smoke detectors that might be triggered by fine dust.  But a smoke detector would likely be better than nothing.  Just remember prevention is always better than discovering a blaze too late.

[mtaylor]

Air assist is a small compressor like one might use for a bubbler in a large fish tank.  The water pump is a fish tank pump but one that moves 10L per minute or so.  You can't use a slow drip as the heat must be dissipated lest you crack the laser tube.  Air bubbles in the tube are also very bad.

 

One other add on... a thermometer for the cooling water.  There's an optimal temperature range with these things usually 20C(68F) to 25C(77F).   I'm using a remote fish tank thermometer.  I also put two one liter bottles of ice into the tank to drop the temp and give me a longer working time before the temp rises too much.  The commercial/production folks generally use a chiller but that's dollars... so there is that trade-off.

 

Cooling water needs to be distilled and also monitored for algae growth.

 

Smoke detectors are good... but watching the cutting is better.  It doesn't take much for one of these to catch fire and get out of hand.

 

There's lots of good information here:  http://www.lightobject.com on these lasers (in the support forum) as well as upgrade and replacement parts. 

[Bob Blarney]

What's the flow rate of the cooling water?  I could set up next to the basement laundry sink, so as to feed a high-flow system with a 6' pressure head.  There would be an overflow reservoir at the top to keep the pressure head and flow constant.

Edited January 3, 2016 by Bob Blarney

[mtaylor]

Bob,

 

10L per minute on the flow rate.

[Bob Blarney]

Thanks.  Hmm, it should be possible to calculate roughly, the diameter of the tubing and pressure head needed to achieve 10 l/m.

 

As for placing the stock material at the correct height, maybe a laboratory scissors jack would be useful.  Do the Google for one, to see if there is one of suitable size and cost:

 

http://www.hometrainingtools.com/laboratory-scissor-jack-8-x-8-stainless-steel?fee=2&fep=740&gclid=CIGu_5nOjsoCFZWCaQodd0gBPQ

 

 

If only a small adjustment in limited space is needed, then I have an idea that would likely work for you.  The cost would not be excessive at all, but it would take time to make it because it's not available on the market so far as I know.

Edited January 3, 2016 by Bob Blarney

[mtaylor]

That scissor jack would be bad... it's reflective and would return the beam back along the path to the tube.   I'm looking into a variable z-table but the ones thtat fit are all powered and my PS doesn't have an extra set of voltage ports..   

 

As for t5956ws unit, it's probably focused at the lens so no need to move the work piece.