This is a detailed article about popular inexpensive semiconductor lasers and about what you can engrave and cut using a 5.6 W semiconductor laser, installed on a 3D printer or CNC machine.
The laser diode is a solid-state source of coherent radiation. In this case it is a solid crystal of aluminate gallium, a source of the laser beam with the wavelength of about 445 nm.
The basic components of the laser are a laser diode, a cooling system and a power driver of the laser diode. The main trick in their production is how to make the driver as compact as possible and at the same time fail-proof, how to ensure sufficient cooling of the laser diode without the crystal degradation.
That is, a laser, ready for operation, has not just an energy source but also a power driver and a cooling system.
We are lucky in this, as diode lasers are rather small and light unlike huge CO2 and fiber lasers. It is easy to install a conventional diode laser on any 3D printer or CNC machine. Besides, the market offers a variety of DIY kits of the makeblock plotter XY 2.0 type, which are also suitable for laser installation.
Standard installation hardware is used for most of lasers, though sometimes one has to play about with a screwdriver.
It is rather easy to connect a laser. When installing it on a 3D-printer, the laser is connected to the power socket of one of the cooling fans of the extruder or to the jack of the power used for the table heating. Typically, diode lasers require the current of 12 v and 1A or more. A 5.6 W laser needs not more than 3-4 A. For the correct connection please read the instructions for your CNC machine or 3D printer.
In some cases, the laser control is similar to the control of a 3D printer or a CNC machine. Namely, by using the G-code (G-code). If you have connected the laser to the output of the fan, you need to see which command is responsible for turning on and off the fan and use it, correspondingly, to turn on and off the laser.
Some CNC devices have the so-called PWM that enables to change the strength of the current supplied to the laser. In this case, you can add grey tones to a monochrome image adding visual volume to a 2D engraving.
On the Internet there are a lot of articles and videos telling how to create the G-code for cutting or engraving. We recommend Inkscape, the program, for which there are several plugins that allow converting vector images to the G-code.
It’s worthwhile saying that such DIY devices as Makeblock plotter XY 2.0 operate well with pixel images, that is, you can use a normal .jpeg file to start the process of cutting or engraving. The program responsible for this is called Benbox.
Perhaps, some of you will think that diode laser installation is a complicated task, but in fact it is not.
It is possible to adjust the focal length of diode lasers using their lenses. This is a big plus. However, not all lasers have high-quality lenses that allow doing so, which is a big minus.
Initially, we set up the laser focus on the surface of the material for cutting on the table of the 3D printer. Then, as the laser cuts the material, we move the laser down the Z-axis, taking care to ensure that the laser cuts through the material being in focus all the time. Only in this way it is possible to obtain a deeper and cleaner cut.
The solid-state lasers, we are talking about, are based on gallium aluminate and have 445 nm wavelength (dark blue). When working with lasers remember to observe safety regulations! Never use the laser without special safety goggles. NEVER aim the laser at people or animals. Never use it for purposes other than intended. All this is very serious. Safety rules violation can cause harm not only to you but also to others.
Lasers below 1W are very popular nowadays. There are many of them on sale. They sell separately and in combination with the so-called DIY engravers. Their average price on Aliexpress is about 200-250 USD.
These lasers can engrave wood, leather, plywood and can cut white paper. In principle, that is all they are designed for.
Their variety is much less. These lasers can cut wood, plywood, PVC, acryl, cardboard, PLA, ABS. But usually the thickness of the cut plywood does not exceed 2-3 mm.
They are not powerful enough for more. In addition, cut edges begin charring significantly and combustion products formation intensifies (ashes).
We tried to cut plywood and wood samples, 5-6 mm thick. The cutting time critically increased. It took us 15-20 minutes to cut a plywood piece 10mm wide and 5,6mm thick. So, this kind of lasers is most effective for cutting the material (plywood, wood, acryl), not more than 2.3 mm thick.
Lasers of this power are of a lot of interest for fans, enthusiasts and makers. These lasers are certainly far from both powerful industrial fiber lasers, which power goes into kilowatts, and from 25-200 W CO2 lasers, but are well suited for cutting plywood and wood 3.2 mm thick, and other materials of greater thickness.
So far, we managed to cut out of plywood an image of a small cat (3x2 cm). It took us a rather short period of time, about 40 minutes.
To do so we had to adjust the laser focus during cutting. Actually, this is a great advantage of diode lasers over CO2 lasers – possibility to adjust the focal length, thus cutting layer by layer.
It is important to remember that when cutting or engraving plastic or acrylic, release of toxic elements (such as chlorine) is possible. The room for work should be necessarily equipped with a hood. Otherwise, it may cause damage to your health.
We should admit that we have not seen or tested lasers of more than 6 W. But at present we are working at the development of a 7 W (7000 mW) and a 10 W (10000 mW) lasers.
It seems that this is the maximum possible power of the laser, as there are serious problems associated with heat removing. Complex devices with water-cooling will increase the laser weight and will make it impossible to install it on many 3D printers and small chassis of Neje type, and will greatly complicate the process of exploitation.
We used a few kinds of three-ply. Though all ply samples looked absolutely the same we obtained different results.
In other articles of ours we have already described in detail how to make a circuit board on a piece of copper-plated glass fiber or how to do engraving on an aluminum workpiece; and demonstrated in detail the process of transparent glass engraving.
Our task is to awaken creativity in people, develop the spirit of makers. So that any person can do something with his hands. We strive to help our readers discover their hidden potentials.
A present for dear ones and kids made with one’s own hands will make happy not only your people but yourself as well. To my mind, it’s very important.
CEO and Founder of Endurance Entrepreneur. Maker. Futurist. Panelist speaker on Annual IEEE Connecticut Conference on Industrial Electronics, Technology & Automation (CT-IETA 2016) October 14 - 15, 2016 ctieta.org/keynote.htmlhttp://EnduranceRobots.comhttp://EnduranceLasers.com
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