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BlackTooth FAQ & Tips!

BlackTooth FAQ & Tips!

Postby Muk » Thu Jun 06, 2013 3:13 pm

Blacktooth Tips:

What are the specs of pieces in this system if I want replacements?

The lens is 20mm wide and a 50.6mm focal length (the one included). This lens will stand up to at least 30PSI air assist.

The mirrors are 25mm wide mirrors.


How bad is the smoke and exhaust?

I'll be honest, it can be pretty awful at times. You'll want a dedicated exhaust line. I initially invested a bunch of money into extra duct work, T-lines, backdraft valves, the whole works to T into my existing house dryer line. It failed miserably.

Cut a new hole, make a dedicated line. Also, invest in a charcoal air filter, it will help. Trust me. They can also be done DIY very inexpensively. Buy a "Universal Pre-filter" and simply wrap it around a screen and have air push down through the screen wrapped in the charcoal laden felt. $20 + fan + screen. Away you go =)



How hard can I push my laser? How long does the tube last?


This is a big one to know. These tubes are rated for 18mA. The power supply is able to push up to 21mA. This is a very dangerous thing to do. If you are pushing the tube beyond 18mA you will cut it's life by QUITE a bit.

The average lifespan of a tube is 1000-1500 hours IF ran at a max of 16mA for most of it's life. It's life will go down if you run constantly at it's max rating.

CO2 laser tubes also have a shelf life. So make sure to only buy a replacement tube close to when you plan to install it, keeping it on a shelf for the future will only compromise it's life span.

To measure your amperage going through your system. You go from the negative line of the tube and run it THROUGH your multimeter/ammeter and back out to the laser PSU. This will give you your amp usage. It will not hurt your multimeter either. Just be sure your connections are very snug since 20,000V is liable to arc very easily if a connection comes loose.


I don't understand the instructions on the BuildYourCNC site very well. Can I get a second look?

Yes. I have done a pictorial of my build prior to warren3D build a FANTASTIC blog with extensive tips on initial software setup and a second look at it all coming together.

My thread here: http://buildyourtools.com/phpBB3/viewto ... 8cdd1802bf
Warrens Blog: http://blacktoothlaser.blogspot.ca/



Can 40w laser cut x amount of material?

A standard 40W CO2 laser will cut up to 1/4" thick of material, be it wood, acrylic, card stock, leather, fabric, foam, cork, etc. (Decent speed and final cut are heavily dependent on a strong air assist upgrade)

Metals cannot be cut due to the power level and wavelength of the CO2 laser. But it can be marked with special solutions like Cermark or Thermark.



Can I boost the power of my laser?


Yes, upgrade your mirrors to SI coated mirrors, using a HQ ZnSe lens and even pushing up to a beam expander will all boost power. The ideal order of experimenation for lowest cost would be changing out for a higher quality lens labeled HQ ZnSE lens. Next would be SI mirrors, which will absorb less heat and reflect better, the last would be to use a beam expander which expands the beam, reducing the heat signature on the mirrors and makes a tighter focal width.


What is Kerf?


Kerf is the cutting width from the lasers beam. This will change in width depending on your power level, higher power will increase your kerf width. This is usually around 0.15mm for a 40w laser using a 2" lens.



What is Focal Length?

Focal length is the distance from the lens to the material for the laser converge into the best focal point. If a lens is listed as 2". You measure 2" from the lens to the material, this will be the tightest point the laser can go before it starts to re-expand again losing focus.


What is D.O.F?

Depth of Field. This is how far the focal point goes before re-expanding again. With a 2" lens, you have approximately 2-3mm of DOF. This means that you'll have 2-3mm of perfectly focused laser before it starts to re-expand again. If you have a 4" lens, you will have up to 7mm of DOF.

For a more indepth explanation, check this out.

http://www.parallax-tech.com/faq.htm



What about cooling? I'm so confused how long these can run!


Cooling is not as tricky as you might think. There is 3 ways to approach this, only 2 really matter for a low scale 40w setup. First one is the cheapest and easiest. The higher the temp of water the worse your performance will be, from what I understand anything in the 30C range is about the most tolerable it gets. Lower is better. But not frozen...from what I've been told a very experienced cutter, he found 8C was the highest power he achieved.

1. Use a 5 Gallon resovoir system which gives you a fairly large space of water to heat up before you need to tend to it. Add about a cup of anti-freeze to the mix of DISTILLED water. You don't want ANY minerals in the water that might build up in your system. The anti-freeze works to keep algae and other ickies from growing in your water.

2. Use a smaller resovoir system (or even closed loop) and install 1 or more radiators found in CPU cooling systems with 120mm fans attached. This will continously cool your water system to ambient room temperatures, but with a tiny resovoir it will be difficult to add things like ice-packs to drop the temps if the ambient is quite hot.

3. Using an industrial coolant system. Overkill and unless your cutting A LOT, this is a very expensive option to take. You can also explore the idea of Peltier cooling but it is extremely expensive electricity/BTU wise compared to an industrial cooler.




Software? What do I need to run this?

If you take the standard parallel cable BoB (Break Out Board), then you will need control software (Mach 3 or EMC2) and CAM software to make your G-Code (such as CamBam). Personally I use CamBam and Mach 3, they work beautifully but don't expect to turn them on and know how they work out of the box. Give yourself a few weeks to get familiar with the basics. CamBam is VERY powerful software for it's price. I'm surprised how much I keep learning on what I can do with it...I highly recommend it if you want as much control as possible.

Mach 3 + CamBam as a bundle costs $310. EMC2 will give you a free replacement for Mach 3 and is exclusively for Linux.

If you use the USB BoB, it will cost an extra $75 + $75 for the software. This is an all-in-one package so no need for Mach 3 or CamBam but I can't attest to it's quality or ease of use since I don't use it.

For etching rasters (jpeg, bmp, tiff, non-vectors, photos), I highly recommend PicEngrave. It has been a labor of love for the past 9 years and John has done a wonderful job with it. It easily compares in quality compared to software that is in the $200-$300 range. John's software runs $40 and can be found here: http://picengrave.com/ (don't let the modest website fool you, this stuff can do amazing things)




What isn't included? What do I need to buy extra?


Software, wiring to connect everything, various electrical crimps to put it together, duct work to pipe the exhaust out, insulation tape for HV wire running to tube (important to get some, since it will make for a nasty shock), 5K potentiometer to control the power level.

I would also recommend running a length of silicone tubing down the length of the HV cable that connects the tube. Silicone is a great insulator and the insulation on the HV cable alone isn't enough to shield the eddie currents around it.




What are some useful modifications that I could use?
(I have all these mods myself, so I can attest to their value) I will post pictures when I think of it.


Temperature probe monitor. Very valuable. This keeps you up to date on your coolant temperature levels.


Voltage meter. This will tell you the exact level of voltage/power you are running telling the laser to run at instead of an arbitrary mark on a drawn wheel around your POT.


Ammeter sensitive to 1mA. This will be sure your not over driving your tube and reducing it's life significantly.


Hour meter. This will tell you exactly how long your system has been 'on' giving you a more accurate bead on the length of your tubes life.


Exhaust fan upgrade. The current fan included is 100CFM. You can buy 120mm fans that push 250CFM and I have included a guide on how to go about doing this here. http://buildyourtools.com/phpBB3/viewto ... 8cdd1802bf

To push the exhaust fan even further, if you have the room/power, I would highly recommend investing in a 600+ CFM "Dust Collector" system. 250CFM is still not suffice to draw all the smoke that can come off of 3mm or 1/8 MDF cutting job.


A cutting surface. I bought myself a aluminum 'egg crate' mesh from my local HVAC company. They are used a cover for fluorescent lights and work great for low impact cutting surface. They come in 4'x8' sheets and are easily cut to fit. The other side is if you can find a steel honeycomb cutting bed to fit. These can be quite costly or fairly affordable depending where you are looking. The benefit of a steel honeycomb is you can use high power magnets to hold material down.




Compressor/Air assist-


The air assist isn't necessary on a laser cutter system but it will benefit you greatly. What it does is, it pushes air through the nozzle where the laser exits the lens. In non-air assist setups, there is no nozzle, simply a laser holder with a mirror. Without air assist, smoke will contaminate and build up on the lens reducing power.

The included air assist with the blacktooth is strong enough to prevent smoke from contaminating the lens, but is not powerful enough to assist in stopping smoke contamination on the material or 'cleaning' your cuts. An upgrade with up to 30PSI through your airline will decrease your Kerf (see definition above), increase cutting depth, clean your cuts and if you have a full 30PSI line, have almost 100% clean cuts from smoke residue. This is especially important with 1/4" material.

I currently run a 30PSI compressor with approximately 150L/min of air flow and I have no smoke residue on any projects and a 0.1-0.15mm Kerf (very fine). Beautiful cuts.

If you have any questions, feel free to message me (email through the board is best since I usually miss my PM's). :mrgreen:
Muk
 
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CNC Machine: BlackTooth

Re: BlackTooth FAQ & Tips!

Postby davoque » Fri Jun 14, 2013 2:43 am

Thanks for posting this Muk, very, very useful.

I have been checking out your build thread too and it has answered some key things for me.

Keep up the great work.
davoque
 
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Re: BlackTooth FAQ & Tips!

Postby Muk » Fri Jun 14, 2013 6:07 pm

You're very welcome. Glad I could be of help. Stuff like this just isn't openly written down really anywhere, so I figured it would help a lot of folks.
Muk
 
Posts: 116
Joined: Tue Nov 20, 2012 3:11 pm
CNC Machine: BlackTooth

Re: BlackTooth FAQ & Tips!

Postby 3d0g » Fri Aug 23, 2013 3:05 pm

Any specific recommendations for the compressor? 150L (5 cubic feet)/min is fairly non-trivial at 30 psi. Generally means a proper shop style compressor with tank...
3d0g
 
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Re: BlackTooth FAQ & Tips!

Postby Muk » Sat Aug 31, 2013 8:29 pm

The compressor that I use is a very small oilless model with no reserve tank. I should get a water filter though as it condenses pretty bad some days....but outside that the compressor looks like this.

http://img3.hyperinzerce.cz/x-cz/inz/61 ... 2650-1.jpg

It's a Thomas 2650. Nothing special...directly hook up air line to it. Expect between 20,000 and 40,000 hours before it requires a rebuild (which a kit for that can be bought for about $50-$60 and can be done by anyone with basic 'tinker' skills)
Muk
 
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CNC Machine: BlackTooth

Re: BlackTooth FAQ & Tips!

Postby 3d0g » Sun Sep 29, 2013 4:12 pm

So I ended up picking up a used Paasche D500 on eBay for <$30. Works great and I'm getting nice clean cuts on 1/4" plywood.

To further extend this awesome FAQ thread, Here's my LinuxCNC stepconf setup for the blackTooth. My stepper driver DIP switches are set exactly like the build instructions - up,up,down,down,up,up,down,down. This gives 1/16th stepping, 2.7A motor current. My motors run quite a bit cooler at 2.7A with no loss of functionality so far. Homing switches are NO and close to ground (parallel port inputs are always pulled high at the computer).

Image
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3d0g
 
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Re: BlackTooth FAQ & Tips!

Postby 3d0g » Sat Oct 05, 2013 9:02 pm

Wiring the blackTooth control panel to the Parallel BOB:

The blackTooth build instructions explain how to hook the four LED control panel to the USB breakout but not the Parallel BOB. Turns out it's very easy. Simply wire the corresponding LED cathodes (top pins on the display) to the matching CP- for the X, Y, and Z axises and wire the anodes (bottom pins) to the 5V terminals. For the on/off LED, wire the cathode to the G terminal on the laser power supply and the anode to the 5V laser supply terminal. Also, remove the 5V wire running from the Parallel BOB to the 5V terminal on the laser power supply. It is not needed and will cause the laser on/off light to always be on if the USB cable is connected.
3d0g
 
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Re: BlackTooth FAQ & Tips!

Postby Muk » Tue Oct 08, 2013 1:23 am

Awesome, thanks for posting more info 3d0g! That's really helpful.
Muk
 
Posts: 116
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CNC Machine: BlackTooth

Re: BlackTooth FAQ & Tips!

Postby 3d0g » Wed Oct 09, 2013 3:04 am

You started it Muk! Such an awesome thread deserves to be continued.

I'm now playing with Jeremy Van Grinsven's duty cycle / PPI configs now from his Buildlog.net 2.x laser (https://github.com/jv4779/2x_laser). I've got it converted over to the blackTooth now and initial tests are very encouraging. Definitely squeezes more power out of the 40W tube and cuts are cleaner. Eager to play with the raster engraving code next... I'll of course post configs / instructions once I've got it all polished & tested.
3d0g
 
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Re: BlackTooth FAQ & Tips!

Postby Muk » Fri Oct 11, 2013 3:12 pm

That PPI makes SUCH a huge difference. Not as much with MDF I found but when it comes to Plywood...it can be tuned to cut it so perfect the edge looks like it was cut with a ultra fine scroll saw blade. Beautiful. I run 500 PPI at 5mm/sec myself for a perfect cut (though speed and PPI would change between types of wood).
Muk
 
Posts: 116
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