Although many things can contribute to this, let’s eliminate LightBurn by checking for possible machine failures.

Goto ezcad to know more.

Your laser: OmTech
Your controller/ firmware: Ruida KT332N

I have what may be an identical machine with the same controller.

The high voltage laser power supply has a digital display:

If yours has the same display, then you can report the current for each test pulse. If not, then read through this for background and we’ll find a different way to verify the beam output.

First test: does the power supply work at all?

• With the machine turned off remove the larger connector (the lower green block in the picture) from the power supply
• Turn the power on
• Put something disposable, like a block of wood, under the laser head
• Press the small red TEST button on the power supply

If the power supply works, the display will read about 14 mA and the laser beam will poke a hole in the wood. If not, the supply is dead and you need a replacement.

Assuming it works, with the power off, plug the green connector back into the power supply.

Second test: does the power supply obey the controller?

Set the KT332N controller for manual pulses (page 35 of the manual). Press MENU → Laser → Laser mode: Continue, Enter on the console to save, then Esc back the normal display. When you press the Pulse button on the controller display the laser beam will turn on and stay on until you release the button.

Set the controller pulse power (page 27 of the manual). Press Enter on the console, move the selection to Power, go through the agonizing process of changing it to 25%, press Enter to save it.

Put something disposable under the laser head, press and hold the Pulse button, and the meter on the power supply should read 7 mA (more or less).

If it does not, then something is wrong between the controller and the HV supply, which will require more testing.

If it does, then the controller behaves as expected.

Third test: does the tube current vary predictably?

On the controller console, set other power levels and verify the current changes roughly in proportion to the setting. For example, if 50% produces 14 mA, then 25% should be about 7 mA and 75% should be about 18%. All those numbers are rubbery, but should give you the idea.

Don’t run the laser at more than about 75% for more than a few seconds while testing, but you can try 99% to find the maximum current the power supply will put out. The tube or its accompanying paperwork may have a maximum current written on it, although the power supply will probably produce far more current than that; OMTech seems to over-promise the laser power by abusing tubes rated for lower power output.

If the power levels vary as expected, then we can proceed to figure out which LightBurn settings changed.

Looks good to me!

At this point we’ve established the controller works, the power supply works, the tube (probably) works, so we can eliminate all of that and move on with finding the real problem.

Assuming for the moment that the tube is lasing properly, the next step is to verify the beam hits (roughly) at the center of all three mirrors and goes out through the middle of the nozzle.

Note that a new machine should be properly aligned, but experience shows assuming it’s in good shape is a bad assumption.

Using the machine console , change the Continue setting to Laser (IIRC. It might be Pulse or something like that, but it’s the other choice) and set the time to 50 ms. Set the power level to 30%, which should be close to the right value.

Then stick a piece of masking tape on the entrance to Mirror 1 (at the output end of the laser tube) and fire a pulse:

• If it burns a hole right through the tape, reduce the time until it doesn’t (using fresh tape each time)
• If it doesn’t do anything, increase the time until it does (more fresh tape)
• When you get a nice toasty mark, you’re done

The mark should be in the middle of the circular aperture. If not, then there’s a problem.

Repeat for Mirror 2 on the left end of the gantry. You may need to increase the power to maintain a toasty mark.

Repeat for Mirror 3 on the laser head, again increasing the power as needed.

If all three marks are pretty close to centered, that’s good. In any case, upload pictures to show off your work.

Squash a piece of tape on the nozzle and fire another pulse. It should produce a hole pretty much in the middle of the circular dent in the tape; if not, that’s a problem. Again, pix to show off the results.

If all that worked, then we can be reasonably sure:

• Controller works
• HV supply works
• Laser tube works
• Mirrors are aligned
• Beam comes out the nozzle

Report back on what you find!

We’ll assume the beam looks OK and comes out the middle of the nozzle, but if the machine continues to not cut, you’re gonna need to show your work.

Combining that bit of new information with the results so far suggests that, despite what you think, the settings are not the same, because the machine passes all the straightforward tests.

Upload the *lbrn2 files in your reply so we can take a look at it.

The first time you do something, you ask “How can anyone possibly do this?” The second time, you say “Hey, that was straightforward!” The third time, you wonder “Why doesn’t everybody know how to do this?”

You just passed stage 1: welcome aboard!

Laser Types

There is a diverse array of laser cutting and engraving machines, defined by various characteristics. These characteristics — and how they interact with each other — dictate the qualities of results, safety, speed, and ease-of-use for that machine.

If you are looking for more details, kindly visit laser controller software.

How a Laser Project is Made¶

To understand the parts each of the characteristics play, let's briefly touch on how a project goes from idea to physical product.

A design is created by a user in design software, and turned into machine instructions (code) through a control software.

LightBurn operates as both a design and control software.

The instructions are delivered to a computer within the laser machine called a controller. The controller translates the instructions into electrical signals that control the machine's motion system. The movement of the motion system delivers the laser beam from the laser source (where the beam is generated) to the directed locations on the material.

Each part of this process is explored in more detail throughout the rest of this article.

Controllers and Firmware¶

The controller — and the firmware it runs — determines whether or not a machine is compatible with LightBurn, and what type of license you need.

A controller is essentially a computer within your laser, and the firmware it runs determines the type of instructions it can translate into signals it delivers to the motion system.

LightBurn needs to know what type of firmware your laser's controller is running to know what "language" to speak to the machine. In most cases, LightBurn can automatically identify the firmware if you set up your machine using Find My Laser, but you'll need to be able to identify the controller yourself in order to complete a manual setup.

LightBurn is currently compatible with three main categories of controllers: GCode, DSP, and Galvo.

• To connect to a GCode-based laser, you'll need a LightBurn Core license.

• To connect to a DSP or Galvo laser, you'll need a LightBurn Pro license. LightBurn Pro licenses also support GCode-based lasers.

Below is a brief description of each type, as well as a list of common controllers/firmware used by each. If you're not sure what controller or firmware your laser uses, consult your machine's manufacturer, or contact us at [ protected].

GCode¶

Most entry-level diode lasers use GCode-based controllers.

Supported controllers/firmware: GRBL, Smoothieware, Marlin, FluidNC, grblHAL, xTool

DSP¶

DSP controllers are common in more industrial-grade machines. If your machine is a CO2 laser in a metal case and has an LCD display, it is most likely a DSP model.

Supported controllers: Ruida, Trocen, TopWisdom

Galvo¶

Galvo lasers use a fixed scanning head mounted to an arm, and project the beam from above. If your laser uses EZCAD2 or SeaCAD as its default software, it is this type of laser.

Supported controllers: EZCAD2, EZCAD2 Lite, BSL

Motion System¶

The motion system consists of the mechanical components that direct the beam from the laser source to the material. These include parts such as motors, mirrors, lenses, and axes.

The choice of motion system determines which LightBurn tools are available for your machine, as well as the maximum job size, and the speed of the laser.

Note

Many tools in LightBurn are only available for machines with a particular type of motion system.

There are two common forms of motion systems:

• Gantry motion systems have frames, wheels, and motors that move a laser head around a work area. Some Gantry lasers use a system of mirrors to reflect a beam from its source, while others hold the laser source and move it around directly. Gantry systems are relatively slow due to the mass of the components moving around, but can have very large working areas.
• Galvo motion systems use tiny moving mirrors to bounce the beam to different locations on a large lense, which focuses the beam and points it back down at the work. Because the mirrors are so lightweight, they can bounce the light around at very high speeds, but Galvos are limited by the size of the lense to relatively small jobs.

Note

All Gantry lasers supported by LightBurn have GCode-based or DSP controllers.

Almost all Galvo lasers supported by LightBurn use EZCAD2 or BSL controllers and require a LightBurn Pro license. However, there are a limited number of GCode-based Galvo lasers that are compatible with LightBurn Core, and require special setup — consult your laser's manufacturer for more information.

Laser¶

The laser beam is generated by a source that dictates its power and wavelength.

These properties determine which materials the beam will be able to mark, engrave, or cut through.

Source¶

• Diode: similar to an LED light, a semiconductor is pumped with electrical current to produce light. These are generally lower power, with a very fine focal dot which forms a rectangular shape. These generally make nice engraves, but poor cuts.
• Diode stack/array: combines the power of many diodes into one beam, to overcome some of the downsides of single-diode beams.
• Glass tube: contains a gas (CO2) that is excited by a DC current to produce a beam. Is cheaper than a Metal RF tube, but needs water-cooling, wears out quicker, and produces a (comparatively) slow "pulsating" beam which has a wider focal dot, and thus is less suited to engraving. The focal dot is round.
• Metal RF tube: contains a gas that is excited by a radio frequency to produce a beam. Is more expensive than a Glass tube, but can be air-cooled, lasts much longer, and produces a more rapid beam-pulse, with a finer focal dot, and is more suited to engraving than Glass tubes. The focal dot is round.
• Solid State Drive: Use a solid (e.g. ruby) as the lasing medium, instead of a gas.
• Fiber: combines several beams into one using fiber optics, to generate more power output.

Wavelength¶

The wavelength of the light generated by the source dictates what materials the beam can interact with, or will pass through.

• Blue Diode — 400-500 nm: interacts with dark-colored materials such as wood, veg-tan leather, and black acrylic, but struggles with light-colored or transparent materials. Can't interact with metals or glass. Produces dark engravings that are great for photos and images.
• CO2 Glass/Metal Tube — nm: great for cutting most laserable materials, including wood, veg-tan leather, fabric, plastics, transparent and light-colored materials, as well as engraving glass and some metals, and removing rust.
• Near Infra Red (IR) Diode — 750- nm (commonly nm): mostly used for engraving some metals.
• Infra Red (IR) Fiber — - nm: great for engraving most metals, removing rust and oxides from metals, and even cutting some.
• Ultra Violet (UV) (Solid State Drive) — 150-400 nm — used for cutting and engraving most materials, including glass.

Power¶

The power dictates the strength of the beam. Lower powered beams may not be able to cut a material that a higher powered version of the same wavelength can, or may require more passes to achieve the same result (increasing job time).

Generally it's best to purchase the highest-powered laser possible, as you can lower power in your settings, to produce "softer" results, where required.

Connection¶

The connection is the method by which LightBurn transfers the instructions to the machine. The current methods supported are as follows:

• USB cable: limited to short distances, USB cables and prone to errors, but are common in many machines. They don't work well when connected via hubs, splitters, or extension cables.
• Network/Data Cable: assentially an internet cable, these can be used over long distances and retain great signal strength.
• LightBurn Bridge: for use with Ruida controllers where a network cable is impractical, LightBurn Bridge relays a signal over TCP.
• Wifi: available on some GRBL controllers, this communication method is wireless.

Accesories¶

There are various accesories and non-critical or optional features available from manufacturers for machines. Some are explored below.

• Homing/limit switches: critical for acurate job-placement and replicability, these small buttons are triggered when the axis of a gantry machine reached its "home" position, and allow the machine to position the laser according to a known physical location.
• Cameras: allow the user to visually place their design onto locations on their physical material. There are two main kinds:
  • Stationary cameras: by far the more popular, these cameras are mounted in a position over the laser's work area that remains the same between jobs and enables a full picture of a machine's bed.
  • Head-mounted cameras: these cameras are attached to the head of a laser, near to the beam. These allow close and safe vicsibility of the laser as it works, along with greater accuracy of design placement, at the cost of having to move the head into a location in order to see it.
• Rotaries: allow cylindrical objects to be engraved. There are two main types, chucks and rollers.
  • Roller-based rotaries: carry an object by rotating wheels beneath it. This style of rotary is not suited to objects that aren't perfectly cylindrical or are prone to slipping, and are tricky to dial in for full-wrap engraves.
  • Chuck-based rotaries: physically hold the workpiece in jaws, and rotate around a known axis by a known number of steps (pulses of the motor).

• Pass-through gates: these are doors that allow material larger than the laser's bed to be placed in the machine, so that a job can be completed in sections.

• Exhaust: a critical safety feature of all laser-machines, these systems ferry the smoke and fumes produced by a job away from the user.

• Enclosures: another critical safety feature, appropriate enclosures protect a user's eyes (by shielding the user's eyes from the beam), and lungs (by containing the fumes so the exhaust can work effectively).

For more help using LightBurn, please visit our forum to talk with LightBurn staff and users, or support.

Are you interested in learning more about galvo controller? Contact us today to secure an expert consultation!