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### Question #: 10119

Question: What is the dot resolution (size) of the BlackTooth laser?

Current Solution

The dot resolution of the blackTooth is a combination of two specifications of the machine:

- The steps/inch (or steps/mm) which is the resolution but not the dot size
- The size of the actual dot, which is not specifically related to the resolution.

The steps per or resolution can actually be a range, since the driver microstepping can be modified.

A simple formula can be used to determine the resolution:

step per inch = (motor steps * microstepping) / (travel at one turn of the motor in inches)

if microstepping is set at 16 (1/16 on the driver) and you are using a pulley that has a pitch of .08 inches and 20 teeth on the drive sprocket

= (200 steps * 16 microsteps) / (20 teeth * .08 inches)
= 3200 steps / 1.6 inches
= 2000 steps per inch

To increase the resolution, just increase the microsteps on the driver.

The actual dot size will depend on the lens you are using, the material being lased, the time period that the laser energy is applied to the material, and the focal height of the lens to the work surface material. The energy from the laser will converge to a point and create a dot on the surface (which is different than the kerf of the laser cut into the material).

The dot will appear in different sizes depending on the material because, say wood, will burn causing a dot that burns the fibers of the wood and spreads a bit. The dot lased on the surface of a plastic, say Plexiglas, the dot will be smaller because the energy is absorbed only at that point, but since Plexiglas is a thermoplastic, a bit of the energy will melt the dot edges depending on the time frame (period) that the energy is applied to the surface.

The focus of the laser energy from the lens looks like a cone converging to a point, then diverges outward after that point. Depending on the distance from the lens to the surface of the material, the dot will be bigger or smaller. You want to find focal point (where the energy is focused into a point). You can use the technique where you lay a material on a slope and lase that material along the slope to find the sweet spot (dot) and that will be your smallest dot, or kerf location. Remember that the kerf will widen or narrow within the material thickness depending on the focal length lens specification (the cone will be shorter or longer depending on the lens focal length).

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### Other Possible Solutions to this Question

• WHAT THICKNESS OF MATERIAL CAN THE BLACKTOOTH LASER CUT?

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.

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WHAT THICKNESS OF MATERIAL CAN THE BLACKTOOTH LASER CUT?

• WHAT CAN ADD TO MY BLACKTOOTH LASER CUTTER MEASURE THE TIME OF USE?

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.

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WHAT CAN ADD TO MY BLACKTOOTH LASER CUTTER MEASURE THE TIME OF USE?

• WHAT SOFTWARE CAN BE USED WITH THE BLACKTOOTH LASER CUTTER?

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.

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). DotG and the Mach3 engrave plugin are two other options and instructions can be found on Dustans page in the gallery on buildyourcnc.com website.

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WHAT SOFTWARE CAN BE USED WITH THE BLACKTOOTH LASER CUTTER?

• WHAT ARE SOME USEFUL MODIFICATIONS CAN APPLY TO THE BLACKTOOTH LASER CUTTER?

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.

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WHAT ARE SOME USEFUL MODIFICATIONS CAN APPLY TO THE BLACKTOOTH LASER CUTTER?

• HOW DIFFICULT IS IT TO BUILD THE BLACKTOOTH LASER CUTTER?

The blackTooth Laser cutter and Engraver can be built in a weekend. Take a look at the build instructions and try to determine if you feel you have sufficient capability to put together the laser system.

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HOW DIFFICULT IS IT TO BUILD THE BLACKTOOTH LASER CUTTER?

• CAN BOOST THE POWER OF MY BLACKTOOTH LASER?

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.

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CAN BOOST THE POWER OF MY BLACKTOOTH LASER?

• WHAT CAN USE BELOW MY WORKPIECE AS SUBSTRATE IN BLACKTOOTH LASER CUTTER?

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.

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WHAT CAN USE BELOW MY WORKPIECE AS SUBSTRATE IN BLACKTOOTH LASER CUTTER?

• WHAT IS THE FORMULA TO DETERMINE STEPS PER INCH OR RESOLUTION FOR EACH AXIS?

The formula and calculation is a starting point to get into the area of steps per inch. You will then need to use the mach3 calibration utility to get the exact steps per inch.

Formula:
step per inch = (motor steps * microstepping) / (travel at one turn of the motor in inches)
if microstepping is set at 16 (1/16 on the driver) then and you are using a sprocket and chain with a pitch of .25 inches and 12 teeth on the drive sprocket
= (200 * 16) / (12 * .25)
= 3200 / 3
= 1066.666 steps per inch

For lead screw that has a travel of .5 inches at one turn like the 5 start 1/2 inch lead screw and using 4 microsteps per step (1/4):
= (200 * 4) / (.5)
= 800 / .5
= 1600 steps per inch

Remember to use the mach3 calibration wizard and double check the driver microstep setting.

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WHAT IS THE FORMULA TO DETERMINE STEPS PER INCH OR RESOLUTION FOR EACH AXIS?

• HOW CAN YOU ENHANCE THE BLACKTOOTH LASER CUTTER?

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.

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HOW CAN YOU ENHANCE THE BLACKTOOTH LASER CUTTER?

• HOW TO COOL THE BLACKTOOTH 40W LASER TUBE

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.

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HOW TO COOL THE BLACKTOOTH 40W LASER TUBE

• WHERE ARE THE WIRING DIAGRAMS FOR BLACKTOOTH LASER CUTTER IN INSTRUCTIONS?

You can find the wiring diagrams for the blackTooth on step 105 and 106 on the list of instructions on the blackTooth page. Step 105 pertains to the parallel breakout board and step 106 pertains to the USB interface board.

wire size

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WHERE ARE THE WIRING DIAGRAMS FOR BLACKTOOTH LASER CUTTER IN INSTRUCTIONS?

• WHAT ARE THE BLACKTOOTH SHIPPING DIMENSIONS?

The blacktooth ships in 3 boxes.

Structure 38x22x5 #54

Components 14x13x13 #30

Laser Tube 35x7x6 #4

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WHAT ARE THE BLACKTOOTH SHIPPING DIMENSIONS?

• WHAT ARE THE BLACKTOOTH LENS SIZES AND FOCAL LENGTH SPECIFICATIONS?

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.

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.

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WHAT ARE THE BLACKTOOTH LENS SIZES AND FOCAL LENGTH SPECIFICATIONS?

• HOW BAD IS THE SMOKE AND EXHAUST USING BLACKTOOTH?

I'll be honest, it can be pretty awful at times. You'll want a dedicated exhaust line. 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 =)

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HOW BAD IS THE SMOKE AND EXHAUST USING BLACKTOOTH?

• HOW DIFFICULT IS IT TO BUILD THE BLACKTOOTH

The blackTooth Laser cutter and Engraver can be built in a weekend. Take a look at the build instructions and try to determine if you feel you have sufficient capability to put together the laser system.

Click the link to add information to this solution:
HOW DIFFICULT IS IT TO BUILD THE BLACKTOOTH

• HOW HARD CAN PUSH MY BLACKTOOTH LASER?

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.

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HOW HARD CAN PUSH MY BLACKTOOTH LASER?

• WHAT IS THE SYSTEM PASSWORD FOR LASER CONTROL UNIT?

The password is: 608

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WHAT IS THE SYSTEM PASSWORD FOR LASER CONTROL UNIT?

• WHAT IS SHIPPING DIMENSIONS AND WEIGHT FOR THE VERTICAL LASER.

Shipping crate size 121" X 36" X 92"

Weight 511 LBS

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WHAT IS SHIPPING DIMENSIONS AND WEIGHT FOR THE VERTICAL LASER.

• WIRING THE BLACKTOOTH LED PANEL TO 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.

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WIRING THE BLACKTOOTH LED PANEL TO PARALLEL BOB

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