Continuing the theme of open source project*. Like all stories begin with words, it was in the evening... In this situation, everything is a little different. Last year it was designed and assembled (almost on a dare) CNC router printed on a 3D printer. . The machine was assembled, launched, and a 5.5-watt laser was installed. After “playing” with the laser, the router itself faded into the background. Started to burn. As you know, the laser works very well with vector graphics; in this regard, it has no equal, but problems begin with the raster. And here the human “I want more!” comes into force. Without hesitation, the first thing that came to mind was a nichrome burner that caught my eye fleetingly a couple of years ago. Yes and financial investments required much less than the cost of the laser itself.

How does this work?
The principle of operation can be compared, or rather tested with a soldering iron on hand. Having heated it to the maximum temperature, begin to slowly pass over the wooden surface, the slower you move, the darker the burnt surface turns out, if you move it very quickly, the surface will not have time to burn out (too short contact with the surface) in the figure you can depict it like this: (for this algorithm and software was built)

At maximum speeds, the color remains virtually unchanged relative to the surface.

Design and build

Initially, the design should not be classic scheme, but after thinking a little I decided to keep the classics, because... it was necessary to test one structural element, namely the X axis with a carriage. Simply put, how will the carriage behave on two linear bearings. Although the machine bears absolutely no load during operation, still two is not enough, the Chinese backlash is merciless

In general, if you don’t count the “small things”, the design uses only 8 printed parts, at which the start of the machine is already possible, in total there are 11 parts per at the moment, (mount for Arduino, cover with coolers, etc.). Due to the “simplicity” of the units, the size in theory can be any, in theory, because shafts of 8 mm over a meter, I think, are no longer very good. And initially the machine was planned to be of such dimensions that it would easily fit an A3 sheet. But due to the fact that, as it turned out later, I did not have 500 mm guides for the X axis, since I used them for the router, and there were 800 mm in the bins. It became a pity to cut, I left them as they were, which made the machine grow in size. As it turned out during operation, this is only a huge plus.

The frame is made of an aluminum square profile 20x20 mm around the perimeter, and the “table” is made of the same material 12x12mm, all fastened with rivets. You can also tighten it with bolts, but I didn’t bother with unnecessary movements, the rivets fulfill their task in full

What’s good about this frame is that wiring is easily hidden in the pipes, thereby improving the overall appearance

General view:

Electronics:

It's all built on the basis Arduino UNO+ cnc shield 3.0 respectively. Moreover, the shield in my household is assigned the role of a gypsy, swinging from machine to machine... one for all, a kind of stupid prostitute)) (I simply don’t have the means to order additionally). Firmware GRBL 1.1. This equipment, including the heat of the tip, is powered by a 12-volt power supply 40A (40 is too much, there was simply no other) 20 - 25 amperes preliminary calculations quite enough.

Forced driver cooling

Software part:

To generate g-code I use a wonderful free program Bmp to GCode Converter. What I really liked is that there are black speed tinctures, i.e. We experimentally select at what speed the black line is burned without spoiling the surface “without digging into it” and set this value in the program. Thus, I came to the conclusion that the tip heat regulator is essentially not needed; it is enough to set the maximum heat once during assembly and find the minimum black speed. Later, when burning, if you need to make the photo lighter, then simply increase the speed of the black color value, the tip moves faster, hence the “drawn” line is lighter. The maximum heat can be limited by only one parameter - the maximum speed of the carriage and acceleration, in my case the maximum speed of the carriage is 16700 mm/s, you can increase the speed by placing a pulley on the motor, larger diameter. Search experiments continue. After the code file is generated, it can already be pushed into any program that “knows how” to send code to the Arduino. I use LaserGrbl, I’m already used to it, it’s convenient that it shows the execution time of the program, you can press pause, and other goodies.

And now the mechanics are assembled, the electronics are connected, the arduino is stitched and configured to the mechanical parameters, I put the parameters on the keyboard at random, without understanding what step to take in Y, in general there are a lot of questions and tests ahead in my head.
First burn

Having looked at this outrage, scratching the back of my head with intelligent eyes, it became clear to that goat that it was necessary to change the program settings based on the characteristics of the mechanics. I decided to google a little and delve deeper into the topic. Tons of useless pages on the Internet, a couple of centuries of videos on YouTube that simply show how he burns them out, without any special voice-over texts, in general, I haven’t learned anything from anyone, everything is so beautiful for everyone, but it’s not clear how. I came across a “mysterious” printer; I won’t divulge its name; many people will understand it anyway; I’ll just say that I got its price right and wrong. And then I finally thought about it. The price for it is not small, there is probably some kind of trick that makes up such a sum, which means I did something wrong...
Taking a good look at the first burning test, we conclude that the carriage speed is too high, low temperature stings, a big step between the lines. Change the settings, increase the temperature, burn:

Well, now I thought better, but what are these wild stripes? I understand that the distance between the stripes is less where there is more black. But the fact is that over time, carbon deposits appear on the tip, just like on soldering irons, and when it reaches a critical mass, let’s say, the deposit chips off and the temperature of the tip rises sharply, as a result of which a difference in shades appears, while the speed is constant. There was no need to invent a bicycle here, everything is already smart people They came up with something for me, where everything is beautiful and without jambs. Ruler. When approaching the X=0 coordinate, the sting hits the metal ruler, literally a centimeter. But here too there is little trick, I didn’t find any information about this on the net, I just followed the logic and errors. Option one is NOT correct:

It is not true in that when approaching the ruler, the tip which receives some pressure on the surface due to, in my case, an ordinary rubber band, you need to “climb” onto the surface of our cleaner, and the thicker it is, the sadder it becomes, so the ruler should be the cheapest , i.e. the thinnest, but this is not enough, due to the fact that the tip is in a red-hot state, and nichrome is not exactly such a hard material, the impact acute angle, simply bends the stings into the ram's horn. Exit. Sharpen the edge a little:

This can be done with the help of the Bulgarian’s daughter, or by any other means; there is no point in doing it too sharply, it’s been tested. Just sharpen the corner and the problem is solved.
Let's try further:

The result is literally obvious. And that’s it, here we go! Burn all the plywood in the house!

I won’t upload a lot of photos, because... Not everything is perfect yet, there are tests ahead, tests and more tests, we need to find its maximum capabilities, thereby increasing the speed. This is not a quick pleasure, the last two burned photos took an average of 5 and a half hours each to print, size 310x410. At the same time average speed based on the code, approximately 50-60% of its capabilities. This is very short, but that’s all. The approximate amount of components for assembling this shaitan machine is about 4 thousand rubles (later I will name a more exact amount). Based on whether this is of interest to you further, the next article will follow, with the completed project and its final capabilities.
Link to kirviks projects

CNC wood burning with nichrome thread with simple control via a computer or laptop

Ease of use

To you NO special training required or learn complex programs for expensive production equipment. To burn a picture, simply load the image in BMP format into the control program and press START. The nichrome CNC burner with nichrome thread will do the rest of the process on its own. For best quality You can pre-process the photo in Photoshop.

To do this, you don’t have to know Photoshop - we give video lessons on preparing photos.

It is not difficult to assemble; for this we have recorded detailed lessons that are provided with all materials. To now make sure that it is not difficult to install, see the story below. Lisa completed the assembly in 35 minutes and spent another 10 minutes editing her photo.

With our equipment Even schoolchildren and girls work. We have made management as simple as possible and does not require special knowledge.

The entire process is as automated as possible. You don’t need a special separate room - you can burn portraits on wood right at home. When burned, a slight smell of wood appears, which does not cause discomfort.

Characteristics of a CNC burner with nichrome thread for wood:

Control program of the same name.

The machine automatically turns on before starting to apply the painting and turns itself off when finished, adjusting the heat of the burning head.

The drawing is raster (line by line), shades are created at the expense of speed. For each shade, the pyroprinter selects desired speed, therefore, it moves along the dark elements of the picture at a reduced speed, and the light ones at an increased speed.

Without additional independent adjustment, the machine works with wooden surfaces and from 4 to 10 mm.

The device is equipped with a contactless sensor that will monitor unusual situations and will be turned off if they occur. This reduces the likelihood of fire to zero.

Specifications:

• Working field size: 42 x 40 cm (easily increased to 90 x 40 cm)*
• Power consumption: 150 W
• Power supply 110 V/220 V (switch on the rear wall of the unit)
• Supported files: bmp, jpg, tiff, gif
• Table in working position: 75 x 75 cm
• Boxes in transport position: 75 x 16 x 20 cm
• Speed ​​(depending on the darkness of the picture):

Plywood format	Burn-in time
A4 (21*30 cm)	1.5-2.5 hours
A3 (30*40 cm)	3-4.5 hours
A2 (60*40 cm)	6.5-7.5 hours
panel (90*40 cm)	8.5-10 hours

• The software runs on Windows XP, 7, 8, 10 (all updates are free, can be installed on any number of computers)
• Connection is via USB port

* - to increase the working field, it is necessary to replace a pair of M8 studs with meter-long studs (sold in construction stores and fastener stores, cost 50-70 rubles. per piece). We do not put long pins in the box due to the fact that they do not fit into the shipping container. When sent second place, they were often bent, which rendered the studs unusable.

Dimensions

The unfolded table, which is assembled from a box, measures 75x75 cm.

Fits easily into the trunk or back seat of a car

Burner with nichrome thread

Each piece of equipment is shipped in a plywood box that converts into a table. To assemble, you will need about twenty minutes and a simple screwdriver (or screwdriver).

We provide video instructions on how to assemble and configure equipment on a computer. Among our clients there were girls who easily coped with self-assembly.

Consumables and Maintenance

You won't need any complicated or expensive maintenance. All you need:

1. Every 5-7 plywood it is necessary to change the tip from nichrome wire. It is made from nichrome wire. Cost 1 piece. approximately 3 rubles. The wire for its manufacture is sold here or in online electronics stores.
2. It is important to periodically lubricate the guides with oil to sewing machines(cost 50-80 rubles per oil can).

Easy start of business at home

Everything you need to get started:

1. Equipment
2. Computer or laptop with Windows (XP, 7, 8, 10)
3. Plywood
4. Electric jigsaw
5. Sandpaper

PyroPrinter is the pride of our engineers

It took us two years and the work of 5 engineers to develop. We conducted hundreds of tests and burned thousands of images, simplifying the process of operating the device as much as possible before we finished developing this nichrome burner. All this so that every time you make a board you get an image high quality. Such products are practically no different from the work of an artist who can work on a painting for a week. The Pyroprinter will create high quality A4 in 2 hours.

This type of business is becoming popular in Germany, Ukraine, Kazakhstan, Russia and a number of European countries. Already more than 25 people from Russia, the CIS and Europe have bought a nichrome CNC burner to create their own home business and successfully produce custom paintings.

What's included?

1. Controller
2. Hairpins (2 pcs.)
3. Controlled nichrome burner (carriage)
4. Plywood blanks (2 pcs.)
5. Brush
6. Sandpaper
7. Ruler for removing carbon deposits
8. Linings for rulers for different thicknesses (2 pcs.)
9. Workpiece mounts (2 pcs.)
10. A set of spare tips and wire (nichrome and tungsten alloy made in Germany)
11. Plywood box-table

Weight about 9.0 kg. dimensions of transport container: 75*18*20 cm

Electronic materials:

1. Licensed Pyroprinter software (all updates are free, can be installed on any number of operating systems)
   • Video:
2. assembly and configuration, first launch
3. photo processing (burning in photographic style)
4. photo processing (effect of a hand-made drawing)
5. how to quickly find clients
6. changing the burning sting
7. preparation of solution for pre-treatment plywood
   • Instructions and master classes:
8. Internet promotion (website, VK, Instagram, etc.)
9. for plywood preparation, treatment with solutions
10. officially for work
11. machine maintenance

Support:

1. If you are afraid that you won’t be able to cope, don’t worry. Our technical support will help you if something doesn’t work out for you.

2. If there are problems installing the program, our engineer can install it remotely via Teamviewer.

Choose?

We will tell you why we abandoned the laser and opted for a CNC burner with nichrome thread.

After much experimentation and pilot machines, we encountered the following nuances when working with CNC laser burning machines and CNC burners with nichrome thread.

Laser CNC burner:

Advantages

1. Higher boundary accuracy. This is due to the fact that a CNC laser machine draws dots on wood. This is his important feature, from which comes its own shortcomings. It is better to write office signs, badges, draw vector objects, texts and images with very clear boundaries, drawn with lines using a CNC laser.

nichrome and laser

2. Burns not only on wood. It also burns onto wooden surfaces and leather, but can also cut out ORACAL-type film. Those lasers that can cut plastic, wood, and foam are more powerful and expensive, respectively.

Cutting letters on Oracal film

3. Low requirements for room temperature.

Disadvantages of a CNC laser burner:

1. Drawing an image with dots. Most main drawback– it is difficult to create halftones for an image using a CNC laser burner. That is, the black dot either exists or it doesn’t. Any artist knows that the effect of volume in an image is achieved by shadows on the surface of the face. Shadows create volume for objects and make them “alive”. In many ways, the perception and recognition of faces by the human brain is designed in such a way that recognition of a person occurs largely due to shadows showing volume. In the case of laser CNC, the shadow can only be obtained by reducing the density of the black dots.

2. Low speed burning. The image is burned at a speed of 10 dots per second. So, we burned a painting measuring 20*20 cm for 10 hours. At the same time, I won’t say that the image was very dark. There is no longer any need to talk about some kind of serial execution of orders - either you will have to install several CNCs, or be content with a small number of orders.

Laser burning of portraits. Screenshot from the screen. Laser burning of A4 format takes about 9 hours

3. Drawing with pixels. As the work progressed, several more unpleasant features of the Laser CNC came to light: when editing an image and enlarging a photograph, the CNC draws “pixels” on the wood. That is, the images are no longer uniform, and rather resemble a mosaic made of squares.

At low magnification the image may become pixelated.

4. Bright glow from the laser, like when welding. I immediately remembered an old friend who works with professional printing equipment (the machine produces matrices for offset printing with a laser) - he has either “minus 6” or “minus 7” vision. There is actually a way to protect yourself from bright light - these are specialized glasses. But it is not always possible to select them correctly - each laser with different lengths laser waves correspond to different glasses that protect specifically from this range of light radiation. If you have children and want to install a laser at home, then this, in our subjective opinion, is simply unthinkable!

The bright light from the laser can seriously damage your vision.

5. Not every tree is suitable. Those who burn on wood know that you can run a soda solution over the wood before burning. But during operation, the laser simply burns the remaining soda on the surface. To prevent this from happening, you have to rinse the workpiece very thoroughly.

Not all plywood is suitable for laser CNC

CNC burner with nichrome thread

Advantages:

1. “Live Images” – with shadows, penumbras and tints. The aesthetics of the image gives the impression of the work. Halftones are drawn due to a simple physical effect - changing the speed of the CNC carriage, and therefore the time of contact of the tip with the surface. In those places where it is necessary to draw a light tone, the wire tip (pen) passes quickly. Where dark elements are needed, the CNC burner holds the carriage with the sting.

High detail – the iris of the eyes is visible at a small size

The nichrome tip gives smooth shades, making portraits “alive” and not “digital”

2. Saturation adjustment The images can be taken directly on the CNC itself by adjusting the temperature of the tip - this way you can get images of different intensities.

CNC tip temperature adjustment

3. Images can be applied to.

Burning on plywood with nichrome

Burning onto the skin with nichrome

4.Portrait burning speed size (A4 21*30 cm) is burned out within 2-3 hours - which is significantly faster than on a CNC laser. In a day, instead of one portrait, you can make 3-4 pieces. Undoubtedly an advantage when burning large formats (A3, A2 and panels).

burning time for A4 takes 2.5-3 hours

Disadvantages of a machine with a nichrome tip:

1. It is necessary to maintain approximately constant temperature into the room. And of course drafts should not be allowed. The movement of air during a draft cools the nichrome tip. Since the CNC operates at a constant speed, light stripes appear in the image due to the cooling of the tip in the wind. In fact, I would classify this drawback as conditional, since it can be solved by closing the window. As for the smell when burning, it is very insignificant - no more than from an extinguished match. Well, you can ventilate the room after finishing the work.

2. The need to change the nichrome thread every 6-8 portraits. This disadvantage has more to do with thread change time than cost. The cost of 1 sting made from nichrome thread will be 2-3 rubles. The time for a shift is about 5 minutes, taking into account the production of the tip shape using pliers made of nichrome wire.

Nichrome thread must be changed every 6-8 portraits

Conclusion

In general, as a result of long experiments and identifying pitfalls, we came to the conclusion that both of them are interesting options, but a laser wood burner is completely unsuitable for our main task - burning paintings and portraits. If the laser is good at producing text fragments (for making signs), patterns or contour drawings, then in terms of portraits the laser definitely loses nichrome CNC. And considering its cost, disadvantages such as a dot pattern without shades and burning time simply negate its advantages. Therefore, we settled on a CNC machine with nichrome thread. Of course, nichrome is not ideal option, but when working, it is enough to prevent drafts and periodically change the tip, and you will get a portrait that a beginner cannot distinguish with the naked eye from the work of an artist.