Laser diodes - Previously, manufacturing lasers was associated with great difficulties, since it requires a small crystal and the development of a circuit for its operation. For a simple radio amateur, such a task was impossible.
With the development of new technologies, the possibility of obtaining a laser beam in everyday conditions has become a reality. The electronics industry today produces miniature semiconductors that can generate a laser beam. Laser diodes became these semiconductors.
The increased optical power and excellent functional parameters of the semiconductor make it possible to use it in high-precision measuring devices both in production, in medicine, and in everyday life. They are the basis for writing and reading computer disks, school laser pointers, level gauges, distance meters and many other useful devices for humans.
The emergence of such a new electronic component is a revolution in the creation of electronic devices of varying complexity. High-power diodes form a beam, which is used in medicine to perform various surgical operations, in particular to restore vision. The laser beam is able to quickly correct the lens of the eye.
Laser diodes are used in measuring instruments in everyday life and industry. The devices are manufactured with different power levels. A power of 8 W is enough to assemble a portable level gauge at home. This device is reliable in operation and is capable of creating a laser beam of very long length. Getting a laser beam into the eyes is very dangerous, since at a short distance the beam is capable of damaging soft tissues.
Design and principle of operation
In a simple diode, a positive voltage is applied to the anode, then we are talking about biasing the diode in the forward direction. Holes from the “p” region are injected into the “n” region of the p-n junction, and from the “n” region into the “p” region of the semiconductor. When a hole and an electron are located next to each other, they recombine and release photon energy with a certain wavelength and phonon. This process is called spontaneous emission. In LEDs it is the main source.
But under certain conditions, a hole and an electron are capable of remaining in one place for a long time (several microseconds) before recombination. If a photon with a resonance frequency passes through this area at this time, it will cause forced recombination, and a second photon will be released. Its direction, phase and polarization vector will absolutely coincide with the first photon.
The semiconductor crystal is made in the form of a thin rectangular plate. In fact, this plate plays the role of an optical waveguide in which radiation acts in a limited volume. The surface layer of the crystal is modified to form the “n” region. The bottom layer serves to create the “p” area.
The end result is a flat p-n junction of significant area. The two side ends of the crystal are polished to create parallel smooth planes that form an optical resonator. A random photon perpendicular to the planes of spontaneous emission will travel along the entire optical waveguide. In this case, before leaving outside, the photon will be reflected several times from the ends and, passing along the resonators, will create forced recombination, forming new photons with the same parameters, which will cause an increase in radiation. When the gain exceeds the loss, the creation of a laser beam will begin.
There are different types of laser diodes. The main ones are made on particularly thin layers. Their structure is capable of creating radiation only in parallel. But if the waveguide is made wide in comparison with the wavelength, then it will function in various transverse modes. Such laser diodes are called multi-house laser diodes.
The use of such lasers is justified to create increased radiation power without high-quality beam convergence. Some dispersion is allowed. This effect is used to pump other lasers, in chemical production, and laser printers. However, if a certain focusing of the beam is necessary, the waveguide must be made with a width comparable to the wavelength.
In this case, the beam width depends on the boundaries that are imposed by diffraction. Such devices are used in optical storage devices, fiber optic technology, and laser pointers. It should be noted that these lasers are not capable of supporting multiple longitudinal modes and emitting a laser beam at different wavelengths at the same time. The band gap between the energy levels of the “p” and “n” regions of the diode affects the wavelength of the beam.
The laser beam immediately diverges at the output, since the emitting component is very thin. To compensate for this phenomenon and create a thin beam, converging lenses are used. For wide multi-house lasers, cylindrical lenses are used. In the case of single-house lasers, when symmetrical lenses are used, the laser beam will have an elliptical cross-section, since the vertical divergence exceeds the beam size in the horizontal plane. A good example of this is the laser pointer.
In the considered elementary device, it is impossible to distinguish a specific wavelength, except for the wave of the optical resonator. In devices that have a material capable of amplifying the beam over a wide range of frequencies, and with several modes, action at different waves is possible.
Typically, laser diodes operate at a single wavelength, which, however, has significant instability and depends on various factors.
Varieties
The design of the diodes discussed above has an n-p structure. Such diodes have low efficiency, require significant input power, and operate only in pulse mode. They cannot work any other way, as they will quickly overheat, so they are not widely used in practice.
Double heterostructure lasers have a layer of substance with a narrow band gap. This layer is located between layers of material that has a wide bandgap. Typically, aluminum gallium arsenide and gallium arsenide are used to make a double heterostructure laser. Each of these connections with two different semiconductors is called a heterostructure.
The advantage of lasers with this special structure is that the region of holes and electrons, called the active region, is located in the middle thin layer. Consequently, many more pairs of holes and electrons will create amplification. In the region with low gain there will be few such pairs left. In addition, light will be reflected from the heterojunctions. In other words, the radiation will be completely located in the region of greatest effective gain.
Quantum well diode
By making the middle layer of the diode thinner, it begins to function as a quantum well. Therefore, electronic energy will be quantized vertically. The difference between the energy levels of quantum wells is used to produce radiation instead of a future barrier.
This is effective in controlling the beam waveform depending on the thickness of the middle layer. This type of laser is much more efficient, unlike a single-layer laser, since the density of holes and electrons is distributed more evenly.
Heterostructure laser diodes
The main feature of thin-layer lasers is that they are not able to effectively contain a beam of light. To solve this problem, two additional layers are applied on both sides of the crystal, which have a lower refractive index, unlike the central layers. This structure is similar to a light guide. It holds the beam much better. These are heterostructures with separate confinement. Most lasers were produced using this technology in the 90s.
Lasers with feedback Mainly used for fiber optic communications. To stabilize the wave at the pn junction, a transverse notch is made to create a diffraction grating. Because of this, only one wavelength is returned to the resonator and amplified. Such lasers have a constant wavelength. It is determined by the grating notch pitch. The notch changes under the influence of temperature. This laser model is the basis of telecommunication optical systems.
There are also laser diodes VСSEL and VECSEL, which are surface-emitting models with a vertical resonator. Their difference is that the model VESSEL The resonator is external, and its design is available with optical and current pumping.
Connection features
Laser diodes are used in many applications where a directed light beam is needed. The main process in assembling a device using a laser with your own hands is the correct connection.
Laser diodes differ from LED diodes in that they have a miniature crystal. Therefore, a large amount of power is concentrated in it, and consequently the amount of current, which can lead to its failure. To facilitate the operation of the laser, there are special device circuits called drivers.
Lasers require a stable power supply. However, there are models of them that have a red glow of the beam and operate normally even with an unstable network. If there is a driver, then the diode still cannot be connected directly. To do this, you additionally need a current sensor, the role of which is often played by a resistor connected between these elements.
This connection has the disadvantage that the negative pole of the power supply is not connected to the minus of the circuit. Another disadvantage is the power drop across the resistor. Therefore, before connecting the laser, you must carefully select the driver.
Types of drivers
There are two main types of drivers that can ensure normal operation of laser diodes.
Pulse driver made by analogy with a pulse voltage converter capable of increasing and decreasing this parameter. The output and input powers of such a driver are approximately equal. However, there is some heat generation, which consumes a small amount of energy.
Line driver operates according to a circuit that most often supplies more voltage to the diode than required. To reduce it, a transistor is needed to convert excess energy into heat. The driver has low efficiency, so it is not widely used.
When using linear microcircuits as stabilizers, as the input voltage decreases, the diode current will decrease.
Since lasers are powered by two types of drivers, the connection diagrams are different.
The circuit may also include a power source in the form of a battery or accumulator.
The batteries must produce 9 volts. The circuit must also have a current-limiting resistor and a laser module. Laser diodes can be found in a faulty computer disk drive.
The laser diode has 3 outputs. The middle pin is connected to the minus (plus) of the power supply. The plus connects to the right or left leg, depending on the manufacturer. To determine the correct pin to connect to, power must be applied. To do this, you can take two 1.5 V batteries and a resistance of 5 Ohms. The minus of the source is connected to the middle leg of the diode, and the plus first to the left, then to the right leg. Through such an experiment, you can see which of these legs is the “working” one. Using the same method, the diode is connected to the microcontroller.
Laser diodes can be powered by AA batteries or a cell phone battery. However, we must not forget that an additional limiting resistor of 20 ohms is required.
Connecting to a home network
To do this, it is necessary to provide auxiliary protection against high frequency surges.
The stabilizer and resistor create a block that prevents current surges. A zener diode is used to equalize the voltage. The capacitance prevents high frequency voltage surges. Proper assembly ensures stable operation of the laser.
Connection procedure
The most convenient for operation will be a red diode with a power of about 200 mW. Such laser diodes are installed on computer disk drives.
- Before connecting using a battery, check the operation of the laser diode.
- You need to choose the brightest semiconductor. If the diode is taken from a computer disk drive, then it emits infrared light. The laser beam must not be pointed at the eyes, as this will cause eye damage.
- The diode is mounted on a radiator for cooling, in the form of an aluminum plate. To do this, pre-drill a hole.
- Apply thermal paste between the diode and the radiator.
- Connect a 20 Ohm and 5 watt resistor according to the circuit with batteries and a laser.
- Bypass the diode with a ceramic capacitor of any capacity.
- Turn the diode away from you and check its operation by connecting the power. A red beam should appear.
When connecting, be aware of safety. All connections must be of high quality.
Diode assemblies and single matrices
Total power from 40 to 4500 W
Our company presents horizontal and vertical diode assemblies with conductive, microchannel or water cooling, operating in continuous or quasi-continuous mode.
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Single diode arrays
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Conductively cooled, high-power laser diode arrays are widely used for pumping in DPSS lasers, in medicine and aesthetics, and in laboratory research. We supply diode arrays with continuous and quasi-continuous pumping.
Possibilities:
Laser diode arrays: 20W~100W continuous pump and 85W~300W quasi-continuous pump
Available wavelengths: 795nm, 808nm, 940nm, 976nm, 1064 (+/-3nm, +/-5nm, +/-10nm)
Available housing types: CS-Mount, Narrow CS-Mount, W2
Available polarization types: TM & TE
Long service life > 10,000 hours
Vertical diode arrays, conduction cooling
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Conductively cooled high power vertical laser diode assemblies are widely used for pumping in Nd:YAG lasers to produce high pulse energy in quasi-continuous wave or pulsed mode.
Possibilities:
Power (quasi-continuous pumping): 100-300 W per die, 1~100 dies per assembly
Assembly method: vertical, horizontal, 2D
Long service life > 1 billion pulses
Available in custom housing
Diode assemblies, micro-channel cooling (MCCP)
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The case with micro-channel cooling (Micro-Channel Cooler Package - MCCP) is designed for high power diode matrices - up to 100 W with continuous pumping. The Micro Channel Cooler (MCC or MC2) is a highly efficient heat sink that can provide more than 1 kW of continuous pumping power from a single diode assembly. Used for heat treatment in industry - metal hardening, laser melting, cutting, welding, etc. They are also widely used in hair removal machines.
Possibilities:
Power (continuous pumping): 60-100 W per die, 1~20 matrices per assembly
Assembly method: vertical, horizontal
Pitch between dies: ~2.0 mm
Fast axis collimation optional
Long service life > 10,000 hours
Available in custom housing
Diode bars (horizontal assemblies), water cooling
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Water-cooled diode arrays (horizontal assemblies) are designed for side pumping in Nd:YAG lasers with simple electrical connectors and water inlet/outlet. Horizontal diode assemblies are key components for laser modules with continuous or quasi-continuous pumping, and are also widely used in repair to replace the emitter.
Possibilities:
Power (continuous pumping): 20-40 W per die, 1~20 matrices per assembly
Power (quasi-continuous pumping): 100-300 W per die, 1~20 dies per assembly
Today, many household and other devices use laser diodes (semiconductors) to create a targeted beam. And the most important point in assembling a laser system yourself is connecting the diode.
Laser diode
From this article you will learn about everything you need for a high-quality connection of a laser diode.
Features of the semiconductor and its connection
The laser model differs from the LED diode in its very small crystal area. In this connection, a significant concentration of power is observed, which leads to a short-term excess of the current value in the junction. Because of this, such a diode can easily burn out. Therefore, in order for the laser diode to last as long as possible, a special circuit is needed - a driver.
Note! Any laser type diode must be powered with a stabilized current. Although some varieties that give red light behave quite stably, even if they have unstable nutrition.
Red laser diode
But, even if a driver is used, a diode cannot be connected to it. A “current sensor” is also needed here. Its role is often played by the common wire of a low-resistance resistor, which is connected to the gap between these parts. As a result, the circuit has one significant drawback - the power minus is “severed” from the minus present in the circuit’s power supply. In addition, this circuit has one more disadvantage - power loss occurs at the current-measuring resistor.
When planning to connect a laser diode, you need to understand which driver it should be connected to.
Driver classification
At the moment, there are two main types of drivers that can be connected to our semiconductor:
- pulse driver. It is a special case of a pulse voltage converter. It can be either downward or upward. Their input power is approximately equal to the output power. In this case, there is a slight conversion of energy into heat. A simplified pulse driver circuit looks like this;
Simplified switching driver circuit
- linear driver. The circuit typically supplies more voltage to such a driver than the semiconductor requires. To extinguish it, a transistor is needed, which will release excess energy with heat. Such a driver has low efficiency, and therefore is used extremely rarely.
Note! When using linear integrated circuit stabilizer chips, the current will decrease as the input voltage across the diode drops.
Line Driver Circuit
Due to the fact that any laser diode can be powered through two different types of drivers, the connection diagram will be different.
Connection Features
The circuit that will be used to power the laser diode may contain not only a driver and a “current sensor”, but also a power source - a battery or battery.
Connection diagram option
Typically, the battery/battery in this case must have a voltage of 9 V. In addition to them, the circuit must include a laser module and a current-limiting resistor.
Note! In order not to spend money on a diode, you can remove it from the DVD drive. Moreover, it must be a computer device, and not a standard player.
Computer DVD drive
The laser semiconductor has three terminals (legs), two of which are located on the sides and one in the middle. The middle output should be connected to the negative terminal of the selected power source. The positive terminal must be connected to the left or right “leg”. The choice of left or right side depends on the semiconductor manufacturer. Therefore, you need to determine which output will be: “+” and “-”. To do this, power must be applied to the semiconductor. Two batteries, each 1.5 volts, as well as a 5 ohm resistor will do the job perfectly here.
The negative terminal at the power supply should be connected to the central negative terminal defined at the diode. In this case, the positive side must be connected to each of the two remaining terminals of the semiconductor in turn. Thus, it can also be connected to a microcontroller.
Power for the laser diode can be provided using 2-3 AA batteries. But if you wish, you can also include a battery from a mobile phone in the circuit. In this case, you must remember that you will need an additional 20 Ohm limiting resistor.
Connection to 220 V network
The semiconductor can be powered from 220 V. But here it is necessary to create additional protection against high-frequency voltage surges.
Option for powering a diode from a 220 V network
Such a scheme should include the following elements:
- Voltage regulator;
- current limiting resistor
- capacitor;
- laser diode.
The resistance and stabilizer will form a block that can prevent current surges. To prevent voltage surges, a zener diode is needed. The capacitor will prevent the appearance of high-frequency bursts. If such a circuit was assembled correctly, then stable operation of the semiconductor will be guaranteed.
Step-by-step connection instructions
The most convenient way to create a laser installation with your own hands will be a red semiconductor, which has an output power of approximately 200 milliwatts.
Note! This is the semiconductor that any computer DVD player is equipped with. This greatly simplifies the search for a light source.
The connection looks like this:
- One semiconductor must be used for connection. They must be checked for functionality (just connect to a battery);
- choose a brighter model. When testing the IR LED (taking it from the computer player), it will glow a faint red glow. Remember that it
DO NOT aim at the eyes, otherwise you may completely lose your vision;
Diode check
- Next, we install the laser on a homemade radiator. To do this, you need to drill a hole in an aluminum plate (about 4 mm thick) with such a diameter that the diode fits into it quite tightly;
- It is necessary to apply a small layer of thermoplastic between the laser and the radiator;
- Next, we take a wire-wound ceramic resistor with a resistance of 20 Ohms with a power of 5 W and, observing the polarity, connect it to the circuit. Through it you need to connect the laser and a power source (mobile battery or battery);
- the laser itself should be bypassed using a ceramic capacitor having any capacitance;
- Then, turning the device away from you, you should connect it to the power supply. As a result, the red beam should turn on.
Red beam from a homemade device
It can then be focused using a biconvex lens. Focus it for a few seconds on one point on the paper that absorbs the red spectrum. The laser will leave a red light on it.
As you can see, we have a working device that is connected to a 220 V network. Using various circuits and connection options, you can create different devices, even a pocket laser pointer.
Conclusion
When connecting a laser diode, you need to remember about safe handling and also know the nuances that are present in its operation. After this, all that remains is to choose the circuit you like and connect the semiconductor. The main thing to remember is that all contacts must be well sealed, otherwise the part may burn out during operation.
Calculation of lumens per square meter for different rooms
To install on homemade laser module or laser pointer, the printer carriage needs to be modified. And I discovered that the pad from the computer case is perfect for these purposes, and one of them happened to be at hand. Poor guy.
I somehow miraculously managed to bend, trim, drill and finally screw it to the carriage. You just need to be creative and precise. She during this brain assemblies is your faithful companion, but can also be your worst enemy if you neglect her!
The carriage was not at right angles to the scanner table, but luckily for me, a small nut saved the day.
Even before this, I found a small pulley from a cassette player, I installed it on the carriage, but then I realized that it was colliding with the X-axis guide, and I had to remove it. But it's definitely worth keeping it in case of future modifications.
Step 11: Etching the PCB
After successfully testing my prototype, assembled on a breadboard and correctly executing some G-code commands, I began creating a printed circuit board. I have never done such things before, but I am an assistant in a chemical laboratory, so working with chemicals does not cause me any fear.
And used it again for this brainstorming Groover, taking from there the layout of the laser board, which is in the EagleCAD format file.
I mirror-printed this layout on plain paper, glued it onto a photosensitive copper-plated board, and drilled the necessary holes with a Dremel. I don't have a newfangled automatic exposure meter, so I just took some alcohol and removed the protective varnish. Using a contour projector pen and a ruler, I drew the paths by hand. This brain pen leaves a very beautiful shiny mark. I also tried using a German fine permanent marker (acid-resistant), but it produced thick, unsightly lines. And with a contour pen you only had to draw a line once, and not several, and you got a good protective layer.
Etched the board crafts I use ferric chloride (III), I don’t like other available remedies. Some steam, others have a strong smell, and others contain peroxide and can explode if kept in a closed container. Therefore, ferric chloride is the best option for both storage and disposal.
However, DO NOT POUR it down the drain! It will corrode your sewer pipes if they are made of copper and kill all the beneficial bacteria in your septic tank.
Step 12: Laser Shield
I don't know how the pins (that connect to the Arduino pins) are soldered on the back side, so I installed them on the top side of the board and pushed them through.
Just in case, I drew drivers on the board brainlaser where which electrical components should be located. Note: test runs without laser can be carried out without this board.
List of electrical parts
I have attached a list from my order from an electronics supplier, which with all the descriptions looks a little scary.
Note 1:
The supplier made a mistake with the relay in the order, so I had to disassemble the old PC power supply, which I found in my supplies. I am immensely happy with my “stash” of old equipment; most of the electronics are still functioning, and I keep them instead of giving them to a collection point. They sell it to Africa as "second hand", although this is not the case. I built this one brain engraver, to show that “old technology” is not trash. In skillful hands, it is as valuable as money.
Note 2 (important):
When connecting an Arduino with the board installed, make sure to connect the external power supply first. I noticed that when connecting the Arduino to USB, without a connected power source, the steppers start to “scream”, which is not at all cool.
Step 13: Alternative Laser Shield (Easylaser Shield)
Groover's laser shield is great, but there are a few things that don't work with the way I control the laser:
- it cannot switch to the microstepping mode of stepper motors.
The steppers in the DVD he used didn't require this, but if you're using different motors from different units, this option can help you control the motors more accurately.
— I was also not happy with the relay that controls turning the laser on/off.
— and finally, the wires going from the laser shield to the laser were too long, I think it would be more correct to place the shield closer to the laser.
So, to summarize:
I modified the driver from Groover
— moved the driver board, placed it on the terminal clamp for the laser module,
— added jumpers to Easydrivers, thereby activating the microstepping mode.
Upgrade: do-it-yourselfer jduffy54 was kind enough to fix the easylaser board. I updated the layout brain boards, the microstepping jumpers should now work as expected.
Step 14: Laser Diode
The laser diode I used is very powerful. This is a targeted 300mW red class 3 laser, which means you MUST use safety glasses. Otherwise, you can get conjunctivitis and cataracts. It's not like smoking, which can possibly lead to cancer. No, if the beam gets into your eyes, then you are guaranteed to get cataracts. And even the beam reflected from the walls is much more dangerous than if you look at the sun. You don't want to risk your vision. Pause…
BE CAREFUL!!
Safety glasses should not transmit radiation with a wavelength of 600-670 nm (optical density 4+). These glasses are not cheap, but the eyes are priceless!
An optical density of 4+ means 10^-4 of incoming (red) light is filtered.
Eg:
300 mW * 10^-4 = 0.03 mW.
Laser diode pinout:
Having removed a laser diode from an old DVD burner or purchased it on the Internet, the first thing you need to do is determine its polarity. I took two for this brain batteries AA in the case, which are “+” and “-”, respectively, and tried to connect them to the laser diode until it lit up.
The housings of laser diodes such as aixiz contain a heatsink. They often come with a focusing plastic lens. Glass lenses are of course better, as they provide 10-20% more usable power.
Laser diode power setting:
Before you connect the laser to the circuit, you need to adjust the “power” it will receive. This is easy to do using the blue potentiometer.
The red laser from the DVD writer can withstand 300mV (under load - accordingly 300mA), but I don’t know how long it will last.
This means that if you want to increase its service life, you can reduce the power supplied to it to 200 mV (under load - 200 mA).
And I advise you, if possible, to find an old DVD writer, because you don’t want to adjust the power of the laser diode on the laser module used in the craft.
It sounds strange, but for this setup we will use the equivalent of a load that needs to be placed in the circuit instead of an actual laser diode. In this case, you can gradually increase the power, while measuring the voltage, and without the risk of damaging the “precious” diode.
In the photo you can see this very equivalent load, it simulates a red laser. And if you have a blue laser, then you need to use 6 1N4001 diodes.
The equivalent load for a red laser is 4 1N4001 diodes and one 1 Ohm resistor.
for a blue laser - 6 1N4001 diodes and one 1 Ohm resistor.
Again, we take a breadboard and connect diodes and a resistor in series, on which the voltage is measured. It doesn’t matter which side of the diodes you place it on. Set the multimeter to 2000mV and apply the probes to the terminals brain resistor. Next, we connect the wires from the laser driver contacts to the breadboard. Load gcodesender, or the terminal you are using, and connect to the microcontroller. Next, we send the command “M3” (turn on the spindle/laser) and readings should appear on the multimeter.
Then turn the potentiometer clockwise until you get the value you need, for example 300mV. This will correspond to what will be supplied to the laser diode.
CW = boost voltage
CCW = reduce voltage
After this, we send the command “M5” to turn off the laser.
Laser Focus:
To focus the laser, I turned the lens until it became a point on the wall, and then tried to light a match.
To “roughly” adjust the focus, I pasted a ruler on the table and installed a laser next to it, so that the edge of its body was at the 0mm mark. Next, I placed a sheet of black paper in front of the laser and moved it until it lit up. Perhaps you also need to “play” with the lens and the distance of the sheet.
I did the final adjustment of the focal length in a similar way, but this time I calculated how long it would take to burn a hole in the paper. This is how I got the focal length closest to ideal.
Step 15: Soft
Determination of working area:
In the Inkscape editor you need to set the dimensions of the working area. To do this, go to “File” - “Document Properties” and change the page to your size.
One thing you need to know before you start engraving is how to get the gcode for your designs. My choice is Inkscape with a modified Groover Gcodetools (Metalevel 8), which is available on its page.
Before creating a gcode pattern, you need to mirror it. If you just want to select everything and reflect it, this can give strange results in Inkscape.
Therefore, before mirroring, select everything (key combination Ctrl + a), combine it into a group (Ctrl + g) and only then reflect it (‘h’). After mirroring, ungroup (Ctrl + Shift + g) and transform it into a path (Ctrl + Shift + c).
gcodetools needs to be copied to “…\Inkscape\share\extensions”.
But now to get gcode you need to do the following:
1. Ungroup all objects (possibly twice)
2. Ctrl + a (select all) - Path - Object to path
3. Selected all - Extensions - Laserengraver - Laser
4. In the "Preferences" section, select the output folder.
5. Important! Switch to the "Laser" tab
6. Enter the desired speed. It can be overwritten later using Gcodesender.
7. Enter the file name + .nc Then click “Apply” and you’re done!
8. Launch Gcodesender, connect to Arduino and load the .nc file. If desired, change the speed.
9. !!WEAR SAFETY GOGGLES!!
10. Click “Print”
Inkscape cheat sheet
Action Keyboard shortcut
Select all Ctrl + A
Group (group) Ctrl + G
Ungroup Shift + Ctrl + G
Mirror (horizontal) reflect horizontally H
vertical V
Convert object to path (convert to path) Shift + Ctrl + C
Align dialog Shift + Ctrl + A
Fill / Stroke dialog Shift + Ctrl + F
Step 16: He came to life!!!
Some of their carved or engraved works.
Self-assembled laser engraver/cutter based on a 2.5 Watt laser module.
In short - XY-kinematics, Marlin firmware and D8-L2500 laser module. The engraver turned out just right - he knows how to burn, both with dots and lines, and most importantly - to cut!
Let me immediately remind you about TB: when working with a laser, use glasses (special ones, taking into account the wavelength of the laser), do not point it at your eyes. The laser is very powerful - even a small reflected radiation can seriously damage the retina.
So, recently I have been struggling to improve the Neje DK-5 laser engraver in order to increase (primarily) the working area and power for processing various materials. In the end, I came to the conclusion that it would be easier to make another one, in the image of simple Chinese engravers on the profile.
As a basis, I took a Chinese kit on an aluminum structural profile 2020 and 2040. Looking ahead, I will say that practice has shown that it is easier to do everything on the same profile 2040, since the ease of installation and rigidity of the frame significantly increases (it is easier to attach elements of body panels to a double profile , legs, cable channels).
The basis of any laser engraver is the laser module. I had experience working with diodes torn from all kinds of equipment, as well as with a module from Neje, but I wanted something more. The Chinese sell all-in-one solid-state laser assemblies: a module in the form of an aluminum radiator of a cylindrical (less often) or rectangular shape (most often). Inside the radiator there is a cylinder with a laser diode, from which two contacts protrude for connecting the supply current. Also installed inside the laser module (and filled with a certain substance) is a current driver for the diode, most often CC (continuous current), less often a driver with support for TTL signals to control the laser power. Often there is a cooling fan on the side or at the end of the radiator. At the other end of the laser output there is a focusing or collimating lens (depending on the purpose of the module). Power supply is usually 5V or 12V.
Here's an example of what's inside (photo not mine, from the open air).
Solid-state laser modules (diode) range from hundreds of milliwatts (for example, 0.3 W) to several units (for example, 5.5 Chinese watts). The more power, the higher the price, and for powerful modules the price is so high that it is easier to consider installing a CO2 tube, but that is a completely different story. Keep in mind that Chinese watts do not always correspond to reality (it is very difficult to estimate the real radiation power). And you can easily buy the same laser diode, labeled 5.5W, 8W or 10W. Perhaps they will differ in the increased current to the diode itself, which greatly (by several times) reduces the life time of the diode.
Since I wanted to not only burn wood, but also cut anything (plastic, plywood, cardboard, etc. - but not metals!), the Neje module was no longer enough for me, especially since the ones torn from CDs don’t roll, and they burn out quickly. It was decided to look for and purchase a several-watt laser module from China; I mainly chose from 450 nanometer laser modules (one of the most affordable).
There are the following types of laser heads on the girbest:
1. 2.5W 12v;
2. 0.5 W 12V;
3. 0.5 W 5 V.
All lasers are 445nm (violet laser), with cooling fan and power supply included.
In addition to the difference in power, it is obvious that the supply voltage is also different. Modules for 5V are very convenient for power supply with power banks/batteries, as well as for ready-made cases with 5V drives. Don't forget that the fan should also be 5V.
When powering stepper motors from 12V, it makes sense to purchase a 12V laser module in order to unify the power supply for the engraver (that is, you only need 1 12V power supply). This is exactly my option. Included with the D8-2500 is a 12V and 5A power supply, which is clearly enough for the laser diode, and in addition remains to power the Ramps electronics and servos.
In the end, I ordered 2.5W/12V. This is what they sent:
Here are some photos of the laser module itself.
Turned on the laser to check the power circuits and correct connections. Somehow I didn’t realize to install an absorbing substrate, and ended up burning my photophone.
So, I’ll tell you about my engraver project, which resulted in an upgrade of my Neje. A kind of mess from an axe. I twisted the laser and removed the electronics. I realized that you can’t make porridge from this. Replaced electronics and laser. As a result, I decided to leave Neje alone and put it away.
I would like to say that there are ready-made frames for installing lasers - XY plotters. But I decided to assemble the frame myself, especially since it is not so difficult.
The idea was very simple - the use of a 2020/2040 structural profile as a frame and guides for a simple A3 engraver, like in Chinese engravers. Rigidity is ensured by special (standard) connections for the structural profile. (internal connectors, corners). Profile dimensions – dimensions of the printed area (minus the carriage). The format was chosen to be slightly larger than an A4 sheet with the expectation of small-sized materials. After Neje with its 3.5x3.5, the difference is simply huge.
About electronics: there are options for RAMPS/LCD/SD/Marlin or CNCshield/GRBL. I removed the stepper motors from the old device (nema17 - can be purchased, they are standard. Great efforts are not needed, since the laser head is lightweight / I think that with small axes you can use inexpensive nema17 type 17H2408. I ordered a profile cut to size and fittings (corners and hardware), plus rollers for carriages.
In any case, if you are interested in assembling a printer yourself, then there is practically no problem finding drawings for printing on a printer (stl) or drawings for cutting acrylic.
A definite plus of the D8-L2500 laser module kit is the presence of a 12V 5A power supply, which is very convenient. I will power the steppers from the same power supply.
What is required for assembly
1 Laser head Engraver/burner - 1 pc.
2 Power supply 12V For powering the laser and drives (1 piece, included in the kit
laser)
3 5V power supply To power the electronics board (optional)
4 2040 profile longitudinal parts of the frame, X-axis - 2 pieces x 420mm
5 2040 profile transverse parts of the frame - 2 pcs x350mm
6 2040 profile Crossbar Y axis - 1 piece x380mm
7 Nema17 Two in X, one in Y - 3 pcs.
with drive ones not necessarily powerful
gears
8 Belt GT2-6mm Two sections in X, one in Y -1.5 meters approximately
9 Limit switches Extreme positions of X-Y axes - 2 pcs.
10 RAMPS 1.4 Control set - 1 piece (*took everything as a set)
11 Ardu Mega R3 electronics* - 1 piece
12 Display+SD shield+cables - 1 pc.
13 A4988 driver, with radiators - 2 pcs.
14 Set of hardware (screws M3, M4, M5, nuts M3 - Set
M4, M5, T-nuts, washers, etc.) For fastening the frame, straps,
engines, for assembling carriages,
etc.
15 Internal corners For fastening frame corners - 4 pcs.
16 Legs or stands In the corners - 4 pcs.
17 Set of wires -Kit
18 Cable channels** - 1.5 meters approximately
19 Rollers For carriages *** 12 (three carriages of 4 pcs each)
* Electronics can be replaced with Arduino Uno/Nano and CNC shield with drivers (A4988/DRVxxxx)
**There is also a spiral cable channel.
*** You can use 3 rollers, or different rollers (by diameter), depending on the selected carriages.
In terms of hardware, I can only give you an approximate estimate; I took a stock of different denominations, then actually looked at what would fit. I recommend buying in wholesale or ordering from Ali (I ended up spending several times more buying at retail than I would have taken a couple of lots on Ali for 50-100 nuts and screws).
If the carriages are made of acrylic, you don’t have to make a double one - I played it safe, because of this the thickness of the carriage has increased and the working area has decreased by almost 6 cm. You can also take the rollers more conveniently, with a pressed-in M5 bushing.
The original OpenBuilds version assumed the use of only 3 rollers - two running ones and one smaller one for pressing.
To make the carriages lighter, instead of several washers, I used printed bushings. Everything is selected and done in three minutes, and printed in about the same time. You can use washers or make other spacers. When designing, it is better to take into account a small margin in the size of the holes, plus, due to plastic shrinkage.
This is what happened.
Second pass on corrugated cardboard. I made two passes due to the thickness. So cardboard cuts well. Unfortunately, the second order with wire extensions for servos and a cable duct did not arrive in time - I now have a limited work area - the wires are stretched, so there will be no test on a large canvas (well, or I’ll post it later).
A small minus - the work of such an engraver in an apartment is evil))) There is a lot of smoke from cardboard and wood. For this reason, I did not cut plastic and acrylic. Need a good hood.
The plans are to make legs, something like a body, and put the wires into the channels (it is possible to run the wires inside the profile or along grooves, with them secured with clips). Ventilation, exhaust hood and housing are very necessary.
So far the plans are to adapt the laser module to work with PWM by replacing the driver with an external one.
And I'm looking for software to convert images to LCD. What I tried did not help me.
Another thought is that you can add a third axis with a gentle stroke. This will allow for more flexible adjustment to materials with greater thickness.
conclusions
In general, the purchase of this module freed up my time, which was spent on altering diodes without housings. There is no need to select a lens and power supply for each one, or shove everything into the body. The cost of the module is quite high, but if you compare the cost of the finished design of a laser engraver of this type, then in the end the benefits are obvious. The fact is that the cost of a laser is more than half the cost of the entire engraver. The rest is the cost of the profile, engines and electronics (little things).