Building 2.x laser cutter

[redskyrc]

Ok,

I am looking to start a 2.0 laser cutter and the plans call for 2 stepper drivers. They are illustrated as KL 4020's. I have 2 questions, what choices do I have to install stepper drivers? The link for the kits sold by buildlog show several possible types:

G540
G251
KL 4030 - this seems like an upgrade to the one that is shown on the D30011 drawings.
KL 201-24

Which one do I choose? I would like to do basic laser cutting like this on balsa and lite ply up to 1/4" thick max. Illustrated is a 4" by 20" piece of 1/16 balsa. This thickness can vary, but no greater than 1/4" thick. Also, I will be wanting to engrave very light part numbers. If you look at my illustration you will see some red letters, those are part numbers.

I would also like to install the z- axis on my 2.x laser cutter. Does this mean I need another stepper motor driver in addition to these two?

Thanks in advance.

[bdring]

Do you plan to use an engraving controller like Thunderlaser or Full Spectrum Engineering or just do cutting.

If you are just doing cutting, the simplest solution is the Interface/Driver PCB. This does a lot of the wiring for you.

[redskyrc]

It will mainly be cutting, except for engraving the part numbers. Can the Interface driver/PCB do light engraving of letters?

[bdring]

The Interface driver/PCB really has nothing to do with it. It is the controller that makes the difference. If you use a commercial controller, the Interface driver/PCB has a lot of wasted circuitry.

If you don't want the commercial controller, you could use the Mach3 plugin for light duty engraving. You could also simply line draw the part numbers at a low power.

[TLHarrell]

That would be my recommendation as well. Do the numbering as lines and have it lightly vector cut them. Works perfect and it's a lot faster than rastering.

[redskyrc]

Ok,

So, let me get this straight. The PCB is simply a circuitry for engraving instead of the fancy commercial controllers.

So I should just order the interface/PCB sold in the kit correct?

What about the stepper drivers? Do I need 3 of them to run the z axis motor?

Which stepper driver is the best for my application? Will the KL4030's do just fine?

[bdring]

So, let me get this straight. The PCB is simply a circuitry for engraving instead of the fancy commercial controllers.

There are two modes "engraving" and "cutting". Cutting is very similar to a regular CNC machine. It uses G-Code which is the language that tells the machine how to move. Engraving is very different than cutting. G-Code does not work. Each time a motor makes a step something needs to determine what the laser should do. Since this happens at a very high rate of speed, the best engravers use fast hardware right inside the machine.

My Interface/Driver PCB is primarily designed for cutting mode. It is wired perfectly for Mach3 and EMC2 software. It includes all the drivers you need for three axes (X,Y and Z). Mach3 does include a simple engraving option that does work well for some people. My board supports that option.

This is the schematic for the laser with the interface/driver PCB

http://www.buildlog.net/cnc_laser/erp/g ... ber=D40006

[redskyrc]

Ok,

According to this schematic, for the type of simple engraving/cutting I am doing, I don't need stepper drivers. Everything is pretty much on the PCB. Great. That makes it simpler for me to hook up.

This below will definitely help others like me understand things a bit better here. PLEASE FEEL FREE TO CORRECT ALL OF THESE.

So, from doing quite a bit of reading and some prior knowledge, here is a rundown of all the components in the schematic pdf you just posted the link to:

the AC power comes into the unit through the "IEC320 POWER ENTRY MODULE"

Some of that power gets split and goes to the rail block, some goes to the "Power Out for Water and Air Pumps"

Now, the AC power that gets routed to the "DIN RAIL Terminal Blocks" then goes to the "24VDC P/S"?

This is where I'm not sure: does the AC power then go to the "LASER TUBE P/S" or the "24VDC P/S"? I think it goes to the 24VDC P/S

From the "24VDC P/S" the power gets converted from AC to DC current and it also acts like a baby step down transformer to 24V correct?

From the "24VDC P/S" that "low voltage" power is sent to the "Interface Driver/PCB" this PCB acts like the central "brain" that receives stimulus/input from the MACH3 or some other engrave controller such as a retinaengrave and outputs signal to all the other components.

The other components are run by this "Interface Driver/PCB" given the input from Mach3.

The 3 stepper motors I think are obvious what they do.

The "Front Interface Panel" is a panel with buttons that control the emergency shutoff switch in case something goes wrong. The manual button to fire the laser manually. I suppose this is for testing purposes??

I don't know what the "POT top, wiper and bottom", or "POT PWM Select" do...Input here?

Ok, looking all the way to the right of the schematic here we have two 24V "Relays" what do these do? I imagine its a safety switch of some sort so that you can shut off the stepper motors in case of a problem...

Looking above the "Relays" you have the "Y-home limit switch" and the "X-home limit switch" I suppose the PCB has circuitry that detects when the steppers have reached their motion to the side "Limit" and reverses the motor so it doesn't force anything too much on the structure of the laser cutter. The cover switch will switch off the machine if the cover is not down. That's a great safety feature right there. Just a little ego booster here... BDRING you are the bomb!

Now, finally the laser tube gets fed power from the "Laser Tube P/S" and powers the laser. The schematic shows a coolant pump that gets switched on/off through the "Flow switch" which is controlled by our brain, the "Interface Driver/PCB". Correct me if I'm wrong here but this is also a safety feature so that if something is wrong with cooling, the "Interface Driver/PCB" shuts the laser down?

I think that covers the bulk of things right? Please feel free to copy and paste this "system summary" and correct as needed. The only thing I really don't get is how there is two power entries, one on the "Laser Tube P/S" and another on the "24VDC P/S" how are these supposed to be wired to the "DIN RAIL TERMINAL BLOCKS"? As a parallel connection? not in "Series"??

Thanks so much everyone. Someone's gotta take the time to ask these things here.

[bdring]

These are all pretty basic electronics questions. I am very concerned that you lack the knowledge to safely build this project. I strongly suggest you purchase a turn key laser. This is a very advanced project.

Here are some answers....

Inside the enclosure, AC is needed for both the laser power supply and 24VDC supply. The DIN rail terminal blocks simplify all the AC wiring. On a schematic, when you see multiple labeled points like "AC LINE" or the ground symbol, it means these are all connected to a common point. It makes the schematic easier to read, rather than having to follow long lines around the schematic. You should use best practices when wiring these. It is better to run each one back to the source rather than daisy chaining them from point to point.

The pot (potentiometer) is used to control of the laser power. The power is controlled by varying the voltage on a pin on the laser power supply between 0-5VDC. A pot can be setup as an adjustable voltage divider. Power can also be controlled via PWM (pulse width modulation). A PWM signal can come from Mach3 or other controller. The switch lets you pick between them.

The relays allow you to optionally control additional external equipment via software like the assist air.

The water switch is there to turn off the laser if the cooling system fails.