Loot boards at home. A simple way to make printed circuit boards (not LUT). Now we prepare fiberglass

When a laser printer is available, radio amateurs use a printed circuit board manufacturing technology called LUT. However, such a device is not available in every home, since even in our time it is quite expensive. There is also a manufacturing technology using photoresist film. However, to work with it you also need a printer, but an inkjet one. It’s already simpler, but the film itself is quite expensive, and at first it’s better for a novice radio amateur to spend the available funds on a good soldering station and other accessories.
Is it possible to make a printed circuit board of acceptable quality at home without a printer? Yes. Can. Moreover, if everything is done as described in the material, you will need very little money and time, and the quality will be at a very high level. Anyway electricity“will run” along such paths with great pleasure.

List of necessary tools and consumables

You should start by preparing the tools, devices and consumables that you simply cannot do without. To implement the most budget-friendly method for manufacturing printed circuit boards at home, you will need the following:

1. Software for drawing design.
2. Transparent polyethylene film.
3. Narrow tape.
4. Marker.
5. Foil fiberglass.
6. Sandpaper.
7. Alcohol.
8. Unnecessary toothbrush.
9. Tool for drilling holes with a diameter of 0.7 to 1.2 mm.
10. Ferric chloride.
11. Plastic container for etching.
12. Brush for painting with paints.
13. Soldering iron.
14. Solder.
15. Liquid flux.

Let’s go through each point briefly, since there are some nuances that can only be reached through experience.
There are a huge number of programs for developing printed circuit boards today, but for a novice radio amateur, the simplest option would be Sprint Layout. The interface is easy to master, it is free to use, and there is a huge library of common radio components.
Polyethylene is needed to transfer the pattern from the monitor. It is better to take a stiffer film, for example, from old covers for school books. Any tape will be suitable for attaching it to the monitor. It’s better to take a narrow one - it will be easier to peel off (this procedure does not harm the monitor).
It’s worth looking at markers in more detail, as this is a sore subject. In principle, any option is suitable for transferring a design onto polyethylene. But to draw on foil fiberglass, you need a special marker. But there is a little trick to save money and not buy quite expensive “special” markers for drawing printed circuit boards. The fact is that these products are absolutely no different in their properties from ordinary permanent markers, which are sold 5-6 times cheaper in any office supply store. But the marker must have the inscription “Permanent”. Otherwise nothing will work.

You can take any foiled fiberglass laminate. It's better if it's thicker. For beginners, working with such material is much easier. To clean it, you will need sandpaper with a grit size of about 1000 units, as well as alcohol (available at any pharmacy). The last consumable can be replaced with nail polish mixing liquid, which is available in any house where a woman lives. However, this product smells quite nasty and takes a long time to dissipate.
To drill the board, it is better to have a special mini-drill or engraver. However, you can go a cheaper route. It is enough to buy a collet or jaw chuck for small drills and adapt it to a regular household drill.
Ferric chloride can be replaced with other chemicals, including those you probably already have in your home. For example, a solution of citric acid in hydrogen peroxide is suitable. Information on how alternative compositions to ferric chloride are prepared for etching boards can be easily found on the Internet. The only thing worth paying attention to is the container for such chemicals - it should be plastic, acrylic, glass, but not metal.
There is no need to talk in more detail about the soldering iron, solder and liquid flux. If a radio amateur comes to the issue of manufacturing printed circuit board, then he is probably already familiar with these things.

Development and transfer of a board design to a template

When all of the above tools, devices and Consumables prepared, you can start developing the board. If the device being manufactured is not unique, then it will be much easier to download its design from the Internet. Even a regular drawing in JPEG format will do.

If you want to go a more complicated route, draw the board yourself. This option is often unavoidable, for example, in situations where you do not have exactly the same radio components that are needed to assemble the original board. Accordingly, when replacing components with analogues, you have to allocate space for them on fiberglass, adjust holes and tracks. If the project is unique, then the board will have to be developed from scratch. This is what the above-mentioned software is needed for.
When the board layout is ready, all that remains is to transfer it to a transparent template. The polyethylene is fixed directly to the monitor using tape. Next, we simply translate the existing pattern - tracks, contact patches, and so on. For these purposes, it is best to use the same permanent marker. It does not wear off, does not smear, and is clearly visible.

Preparation of foil fiberglass laminate

The next step is the preparation of fiberglass laminate. First you need to cut it to the size of the future board. It is better to do this with a small margin. To cut foil fiberglass laminate, you can use one of several methods.
Firstly, the material can be cut perfectly using a hacksaw. Secondly, if you have an engraver with cutting wheels, it will be convenient to use it. Thirdly, fiberglass can be cut to size using a utility knife. The principle of cutting is the same as when working with a glass cutter - a cutting line is applied in several passes, then the material is simply broken off.

Now it is imperative to clean the copper layer of fiberglass from the protective coating and oxide. The best way There is no better way to solve this problem than using sandpaper. The grain size is taken from 1000 to 1500 units. The goal is to obtain a clean, shiny surface. It is not worth sanding the copper layer to a mirror shine, since small scratches from sandpaper increase the adhesion of the surface, which will be needed later.
Finally, all that remains is to clean the foil from dust and fingerprints. To do this, use alcohol or acetone (nail polish remover). After processing, we do not touch the copper surface with our hands. For subsequent manipulations, we grab the fiberglass by the edges.

Combination of template and fiberglass

Now our task is to combine the pattern obtained on polyethylene with the prepared fiberglass laminate. To do this, the film is applied to the desired location and positioned. Leftovers are wrapped on reverse side and are attached using the same tape.

Drilling holes

Before drilling, it is recommended to secure the fiberglass laminate with the template to the surface in some way. This will allow for greater accuracy and will also prevent sudden rotation of the material as the drill passes through. If you have a drilling machine for such work, then the problem described will not arise at all.

You can drill holes in fiberglass at any speed. Some work at low speeds, others at high speeds. Experience shows that the drills themselves last much longer if they are used at low speeds. This makes them more difficult to break, bend and damage the sharpening.
The holes are drilled directly through the polyethylene. Future contact patches drawn on the template will serve as reference points. If the project requires it, we promptly change drills to the required diameter.

Drawing tracks

Next, the template is removed, but not thrown away. We still try not to touch the copper coating with our hands. To draw paths we use a marker, always permanent. It is clearly visible from the trail it leaves. It is better to draw in one pass, since after the varnish, which is included in the permanent marker, has hardened, it will be very difficult to make edits.

We use the same polyethylene template as a guide. You can also draw in front of the computer, checking the original layout, where there are markings and other notes. If possible, it is better to use several markers with tips of different thicknesses. This will allow you to draw both thin paths and extensive polygons more efficiently.

After applying the drawing, be sure to wait some time necessary for the final hardening of the varnish. You can even dry it with a hairdryer. The quality of future tracks will depend on this.

Etching and cleaning marker tracks

Now comes the fun part - etching the board. There are several nuances here that few people mention, but they significantly affect the quality of the result. First of all, prepare the ferric chloride solution according to the recommendations on the package. Usually the powder is diluted with water in a ratio of 1:3. And here's the first piece of advice. Make the solution more saturated. This will help speed up the process, and the drawn paths will not fall off before everything necessary is etched out.

Immediately the second tip. It is recommended to immerse the bath with the solution in hot water. You can heat it in a metal bowl. Increasing the temperature, as has been known since school, significantly accelerates the chemical reaction, which is what etching our board is. Reducing the procedure time is to our advantage. The tracks made with a marker are quite unstable, and the less they sour in the liquid, the better. If at room temperature the board is etched in ferric chloride for about an hour, then in warm water this process is reduced to 10 minutes.
In conclusion, one more piece of advice. During the etching process, although it is already accelerated due to heating, it is recommended to constantly move the board, as well as clean off the reaction products with a drawing brush. By combining all the manipulations described above, it is quite possible to etch out excess copper in just 5-7 minutes, which is simply an excellent result for this technology.

At the end of the procedure, the board must be thoroughly rinsed under running water. Then we dry it. All that remains is to wash away the traces of the marker that are still covering our paths and patches. This is done with the same alcohol or acetone.

Tinning of printed circuit boards

Before tinning, be sure to go over the copper layer again with sandpaper. But now we do it extremely carefully so as not to damage the tracks. The simplest and affordable way tinning - traditional, using a soldering iron, flux and solder. Rose or Wood alloys can also be used. There is also so-called liquid tin on the market, which can greatly simplify the task.
But all these new technologies require additional costs and some experience, so the classic tinning method is also suitable for the first time. Liquid flux is applied to the cleaned tracks. Next, solder is collected onto the soldering iron tip and distributed over the copper remaining after etching. It is important to warm up the traces here, otherwise the solder may not “stick”.

If you still have Rose or Wood alloys, then they can be used outside the technology. They melt just fine with a soldering iron, are easily distributed along the tracks, and do not bunch up into lumps, which will only be a plus for a beginning radio amateur.

Conclusion

As can be seen from the above, the budget technology for manufacturing printed circuit boards at home is truly accessible and inexpensive. You don't need a printer, an iron, or expensive photoresist film. Using all the tips described above, you can easily make the simplest electronic radios without investing a lot of money in it, which is very important in the first stages of amateur radio.

I don’t know about you, but I have a fierce hatred for classic circuit boards. The installation is such a crap with holes where you can insert parts and solder them, where all connections are made through wiring. It seems simple, but it turns out to be such a mess that understanding anything in it is very problematic. Therefore, there are errors and burnt parts, incomprehensible glitches. Well, screw her. Just spoil your nerves. It’s much easier for me to draw a circuit in my favorite one and immediately etch it in the form of a printed circuit board. Using laser-iron method everything comes out in about an hour and a half of easy work. And, of course, this method is excellent for making the final device, since the quality of printed circuit boards obtained by this method is very high. And since this method is quite difficult for the inexperienced, then I will be happy to share my proven technology, which allows you to get printed circuit boards the first time and without any stress with tracks 0.3mm and clearance between them up to 0.2mm. As an example, I will make a development board for my controller tutorial AVR. You will find the principle in the entry, and

There is a demo circuit on the board, as well as a bunch of copper patches, which can also be drilled out and used for your needs, like a regular circuit board.

▌Technology for manufacturing high-quality printed circuit boards at home.

The essence of the method for manufacturing printed circuit boards is that a protective pattern is applied to the foil-coated PCB, which prevents etching of copper. As a result, after etching, traces of conductors remain on the board. There are many ways to apply protective patterns. Previously, they were painted with nitro paint using a glass tube, then they began to be applied with waterproof markers or even cut out of tape and pasted on the board. Also available for amateur use photoresist, which is applied to the board and then illuminated. The exposed areas become soluble in alkali and are washed off. But in terms of ease of use, cheapness and speed of production, all these methods are much inferior laser-iron method(Further LUT).

The LUT method is based on the fact that a protective pattern is formed by toner, which is transferred to the PCB by heating.
So we will need a laser printer, since they are not uncommon now. I use a printer Samsung ML1520 with original cartridge. Refilled cartridges fit extremely poorly, as they lack density and uniformity of toner dispensing. In the print properties, you need to set the maximum toner density and contrast, and be sure to disable all saving modes - this is not the case.

▌Tools and materials
In addition to foil PCB, we also need a laser printer, an iron, photo paper, acetone, fine sandpaper, a suede brush with metal-plastic bristles,

▌Process
Next, we draw a drawing of the board in any software convenient for us and print it. Sprint Layout. A simple drawing tool for circuit boards. To print normally, you need to set the layer colors on the left to black. Otherwise it will turn out to be garbage.

Printing, two copies. You never know, maybe we'll screw one up.

This is where the main subtlety of the technology lies LUT because of which many have problems with the release of high-quality boards and they give up this business. Through many experiments, it was found that the best results are achieved when printing on glossy photo paper for inkjet printers. I would call photo paper ideal LOMOND 120g/m2

It is inexpensive, sold everywhere, and most importantly, it gives an excellent and repeatable result, and its glossy layer does not stick to the printer’s stove. This is very important, as I have heard about cases where glossy paper was used to dirty the printer oven.

We load the paper into the printer and confidently print on the glossy side. You need to print in a mirror image so that after transfer the picture corresponds to reality. I can’t count how many times I made mistakes and made incorrect prints :) Therefore, for the first time, it’s better to print on plain paper for a test and check that everything is correct. At the same time, you will warm up the printer oven.

After printing the picture, in no case Do not grab with your hands and preferably keep away from dust. So that nothing interferes with the contact of the toner and copper. Next, we cut out the board pattern exactly along the contour. Without any reserves - the paper is hard, so everything will be fine.

Now let's deal with the textolite. We will immediately cut out a piece of the required size, without tolerances or allowances. As much as needs.

It needs to be sanded well. Carefully, trying to remove all the oxide, preferably in a circular motion. A little roughness won't hurt - the toner will stick better. You can take not sandpaper, but an “effect” abrasive sponge. You just need to take a new one, not greasy.

It’s better to take the smallest skin you can find. I have this one.

After sanding, it must be thoroughly degreased. I usually use my wife’s cotton pad and, after moistening it thoroughly with acetone, I thoroughly go over the entire surface. Again, after degreasing, you should never grab it with your fingers.

We put our drawing on the board, naturally with the toner down. Warming up iron to maximum, holding the paper with your finger, firmly press and iron one half. The toner needs to stick to the copper.

Next, without allowing the paper to move, iron the entire surface. We press with all our might, polish and iron the board. Trying not to miss a single millimeter of the surface. This is a most important operation; the quality of the entire board depends on it. Don’t be afraid to press as hard as you can; the toner won’t float or smear, since the photo paper is thick and perfectly protects it from spreading.

Iron until the paper turns yellow. However, this depends on the temperature of the iron. My new iron hardly turns yellow, but my old one almost charred - the result was equally good everywhere.

Afterwards you can let the board cool down a bit. And then, grabbing it with tweezers, we put it under water. And we keep it in the water for some time, usually about two to three minutes.

Taking a suede brush, under a strong stream of water, we begin to violently lift the outer surface of the paper. We need to cover it with multiple scratches so that the water penetrates deep into the paper. In confirmation of your actions, the drawing will be shown through thick paper.

And with this brush we brush the board until we remove the top layer.

When the entire design is clearly visible, without white spots, you can begin to carefully roll the paper from the center to the edges. Paper Lomond Rolls out beautifully, leaving 100% toner and pure copper almost immediately.

Having rolled out the entire pattern with your fingers, you can thoroughly scrub the entire board with a toothbrush to clean out the remaining glossy layer and scraps of paper. Don’t be afraid, it’s almost impossible to remove well-cooked toner with a toothbrush.

We wipe the board and let it dry. When the toner dries and turns gray, it will be clearly visible where the paper remains and where everything is clean. The whitish films between the tracks must be removed. You can destroy them with a needle, or you can rub them with a toothbrush under running water. In general, it is useful to walk along the paths with a brush. The whitish gloss can be pulled out of narrow cracks using electrical tape or masking tape. It doesn't stick as violently as usual and doesn't strip off the toner. But the remaining gloss comes off without a trace and immediately.

Under the light of a bright lamp, carefully examine the toner layers for tears. The fact is that when it cools, it can crack, then a narrow crack will remain in this place. Under the light of the lamp, the cracks sparkle. These areas should be touched up with a permanent marker for CDs. Even if there is only a suspicion, it is still better to paint over it. The same marker can also be used to fill in poor-quality paths, if any. I recommend a marker Centropen 2846- it gives a thick layer of paint and, in fact, you can stupidly paint paths with it.

When the board is ready, you can water the ferric chloride solution.

Technical digression, you can skip it if you wish.
In general, you can poison a lot of things. Some poison in copper sulfate, others in acidic solutions, and I in ferric chloride. Because It is sold in any radio store, it transmits quickly and cleanly.
But ferric chloride has a terrible drawback - it just gets dirty. If it gets on clothes or any porous surface like wood or paper, it will be a stain for life. So put your Dolce Habana sweatshirts or Gucci felt boots in the safe and wrap them with three rolls of tape. Ferric chloride also destroys almost all metals in the most cruel way. Aluminum and copper are especially fast. So the utensils for etching should be glass or plastic.

I'm throwing 250 gram packet of ferric chloride per liter of water. And with the resulting solution I etch dozens of boards until the etch stops.
The powder must be poured into water. And make sure that the water does not overheat, otherwise the reaction will release a large amount of heat.

When all the powder has dissolved and the solution has acquired a uniform color, you can throw the board in there. It is desirable that the board floats on the surface, copper side down. Then the sediment will fall to the bottom of the container without interfering with the etching of the deeper layers of copper.
To prevent the board from sinking, you can stick a piece of foam plastic to it with double-sided tape. That's exactly what I did. It turned out very convenient. I screwed in the screw for convenience, so that I could hold it like a handle.

It is better to dip the board into the solution several times, and lower it not flat, but at an angle, so that no air bubbles remain on the surface of the copper, otherwise there will be jambs. Periodically you need to remove it from the solution and monitor the process. On average, etching a board takes from ten minutes to an hour. It all depends on the temperature, strength and freshness of the solution.

The etching process accelerates very sharply if you lower the hose from the aquarium compressor under the board and release bubbles. The bubbles mix the solution and gently knock out the reacted copper from the board. You can also shake the board or container, the main thing is not to spill it, otherwise you won’t be able to wash it off later.

When all the copper has been removed, carefully remove the board and rinse it under running water. Then we look at the clearing so that there is no snot or loose grass anywhere. If there is snot, then throw it into the solution for another ten minutes. If the tracks are etched or breaks occur, it means the toner is crooked and these places will need to be soldered with copper wire.

If everything is fine, then you can wash off the toner. For this we need acetone - the true friend of a substance abuser. Although now it is becoming more difficult to buy acetone, because... Some idiot from the state drug control agency decided that acetone is a substance used to prepare narcotics, and therefore its free sale should be prohibited. It works fine instead of acetone 646 solvent.

Take a piece of bandage and thoroughly moisten it with acetone and begin to wash off the toner. There is no need to press hard, the main thing is not to mess around too quickly so that the solvent has time to be absorbed into the pores of the toner, corroding it from the inside. It takes about two to three minutes to wash off the toner. During this time, even the green dogs under the ceiling will not have time to appear, but it still won’t hurt to open the window.

The cleaned board can be drilled. For these purposes, I have been using a motor from a tape recorder, powered by 12 volts, for many years. It’s a monster machine, although its lifespan lasts for about 2000 holes, after which the brushes burn out completely. You also need to rip out the stabilization circuit from it by soldering the wires directly to the brushes.

When drilling, you should try to keep the drill strictly perpendicular. Otherwise, then you’ll put a microcircuit in there. And with double-sided boards, this principle becomes basic.

The manufacture of a double-sided board occurs in the same way, only here three reference holes are made, with the smallest possible diameter. And after etching one side (at this time the other is sealed with tape so that it does not get etched), the second side is aligned along these holes and rolled. The first one is sealed tightly with tape and the second one is etched.

On the front side you can use the same LUT method to apply the designation of radio components for beauty and ease of installation. However, I don’t bother that much, but comrade Woodocat from the LJ community ru_radio_electr He always does this, for which I have great respect!

Soon I will probably also publish an article on photoresist. The method is more complicated, but at the same time it gives me more fun to do - I like to play tricks with reagents. Although I still make 90% of the boards using LUT.

By the way, about the accuracy and quality of boards made using the laser ironing method. Controller P89LPC936 in the case TSSOP28. The distance between the tracks is 0.3mm, the width of the tracks is 0.3mm.

Resistors on the top size board 1206 . What's it like?

In this article I want to describe laser-iron technology (LUT) for the production of printed circuit boards, which I myself have been using for quite a long time. This technology described on many sites, but since you are already on my site you can read it right here.

Laser ironing technology - stages of implementation

Step #1. We draw the board on the computer. You can use specialized programs that automatically wire the board according to schematic diagram, I use the program for this. Before that, for small circuits, I used to use it, which, by the way, is also a convenient program.

Step #2. A blank for the future printed circuit board is cut out of foil fiberglass laminate. Next, the side on which the conductors will be needs to be cleaned, at least with the same zero, but lately I’ve been doing this with a regular eraser. Then the foil side must be degreased with acetone.

Step #3. On laser printer We print out the pattern of the circuit board tracks on glossy thin paper. I use this kind of paper from a catalog of electronic components, which at one time was sent to me for free from some site, I don’t remember now.

Before printing a drawing, it is advisable to run one sheet of paper to warm up the drum. Then, in the printer settings, you need to turn off the toner economy mode so that the print is as saturated as possible.

Step #4. After the image has been printed, we cut out the outline, not forgetting to leave a margin approximately equal to the width and height of the board. Place the sheet face up. Prepare strips of paper tape about a centimeter long. Next, we place the board with the foil side on the paper, precisely positioning it along the contour.

Then, pressing the board tightly to the paper, carefully wrap the edges of the paper, securing them with pre-prepared strips of tape.

Now we take an ordinary iron, turned on at maximum temperature, and carefully iron the board wrapped in paper from the side of the drawing.

It is important not to press too hard as there is a risk that the toner may splatter.

Step 5. Then we place the board with the stuck paper in hot water at about 50 degrees and wait until the paper gets wet.

After the paper swells, it must be carefully separated from the board. Roll the remaining paper with your finger under water. We check the dried board for possible defects; if the toner still comes off in some places, you can finish drawing it with a regular permanent marker.

Step 6. We etch our board in ferric chloride. In order for the etching process to proceed quickly, the solution must be heated to 40-50 degrees.

The need to make hardware periodically arises among many techies. Sometimes the task allows you to screw everything up with wires on the breadboard, and sometimes, unfortunately, you need something more serious. So one day I was overtaken by the need to make printed circuit boards... Laser-ironing technology for handicraft manufacturing of circuit boards is at first very repulsive due to its randomness (what to print on, how to heat it, with what force to press, how to tear it off, etc.), but friends shared their experience , and it turned out that it really isn't that difficult. LUT is undeniably cheaper than any other option, and (surprisingly) quite suitable for two-layer boards.

Those who are interested in something more complex, more expensive and more precise can do it, but our technique (the main element of which is special paper) allows us to consistently work on 0.3/0.3 mm busbars, so in our community there is an opinion that photoresists are not needed.

Anyone who doesn’t see the point in handicraft production of boards will most likely be able to remember a couple of cases when they had to cut tracks and solder wiring on a whole batch of boards. And having made one board at home, you can thoroughly debug it and gain confidence in factory boards.

Below the cut, I will share a deterministic method for manufacturing two-layer printed circuit boards using LUT technology with various backup circuits in case of jambs. From idea to inclusion. We will work with KiCad, Inkscape, sandpaper, iron, ammonium persulfate and engraver.

Any device starts with a circuit. Most board errors can be eliminated at the design stage. And in order for the circuit to be guaranteed to match the board, you need good EDA software. For example, KiCad.

KiCad --> Board

If you are still working with proprietary limited solutions, start with the article or skip this section.

We use the recently released KiCad 5, because I deeply like this program, its community (including CERN) and the idea of ​​​​multi-platform FOSS in general.

So the algorithm with life hacks:

Board --> SVG

When the board is ready, you need to convert it to SVG for further refinement. It’s better to unload the board from EDA without mirroring, so as not to get confused and mirror it properly.

And we need to mirror it only front layer F.Cu. Since we look at the back layer of B.Cu in the editor from the front, it is already mirrored. For reliability, it is better to place at least some text on both layers and make sure that this text is not readable))

( , ) It is better to upload from KiCad via File | Plot, since it is possible to make all the holes 0.35 mm at once. For manual LUT, greasy holes are not needed, it is better to have more copper and clean it off with a drill.

Actually:

1. Load both layers into Inkscape.
2. We set the document measurement units to millimeters, and the A4 sheet format.
3. Adding even more white lettering to the metallization areas. KiCad can't do this, write in the comments if your EDA can.
4. Let's group so that there are only two objects.
5. Align (Ctrl+Shift+A), the distance between the layers (their overall holes) should be at least a centimeter.
6. We mirror the front layer using the button on the top toolbar.
7. Save as SVG.

Now we need to send the SVG to the printer on plain paper. And do the following with this paper:

1. Attach components to it and check the footprints (which, in any case, have already come from the store: if you have more than three to five components on the board, it’s difficult to trace everything in one evening)
2. Attach to the PCB and punch 4 dimensional holes in the corners that we added
   • Take a core (or nail) with a hammer and make a super-precise, shallow dent that will absorb stray drill bits. The impact force must be such as not to deform the board.
3. Drill 4 holes with the thinnest drill (0.6-0.8) exactly at 90 degrees. This is perhaps the most difficult part, but mistakes are acceptable; a method for their subsequent correction has been invented.
   • If you have a machine, you are lucky.
   • If you have a CNC, you are very lucky; figure out all the holes according to the DRL file right now without any cores.

• It is easy to guess that the holes are needed to accurately orient the front layer relative to the back one. If you want something simpler, there is a way without holes: very precisely fold the piece of paper with the template and place the PCB inside. As already mentioned, a slight deviation will not be fatal (unless, of course, the holes have not yet been drilled)
• Another folding modification:
  We place freshly printed sheets with the top and bottom layers on top of each other, shining them through with a lamp and aligning them. We fasten in several places along the edges. We put textolite into the resulting envelope.
• shared . Thank you!

Ok, this is the section about SVG, and we’ve already moved on to the machines... That’s it, the final touch on SVG and you won’t need a computer anymore:

Fill everything with black so that parts of the PCB that do not belong to the board are not etched and do not saturate the ammonium persulfate with copper. Yes, ferric chloride is also possible, but ammonium is blue.

SVG --> Textolite

Also, we have information about the suitability of paper Black Diamond. Other brands may or may not have the required properties. HP does not fit exactly (melts under the iron), Lomond fits conditionally, "but somehow average". You can experiment with different glossy photo paper for inkjet printing . Write in the comments what it’s like with other papers)

Algorithm:

1. Set the iron to heat up to maximum temperature.
2. We grind the textolite on both sides with fine sandpaper and a plumbing abrasive sponge (,), dish sponge or an abrasive eraser.
3. If your printer can accept formats other than A4, Cut a strip from A4 to the size of the image. Paper is extremely valuable: if you managed to get it, you need to save it.
4. We push it into the printer with the narrow side. We check that the image of the two layers of the board does not exceed the width of the cut strip in width and 210 in height.
5. We laser print with original toner in a cartridge on this glossy photo paper for inkjet printers.
6. Without touching the toner, cut the layers into two separate pieces of paper and make large holes on both layers.
7. We insert straight pins (for example, from a PLS/PLD comb) into the 4 dimensional holes.
8. Place the front layer.
9. We iron it evenly, without pressing too hard, until the paper turns yellow (or any other signs from above, this is still LUT: it’s probably impossible to completely get rid of the magic). The pins can be pulled out when the paper begins to stick and loses its ability to move.
10. Without tearing the paper off the PCB, we repeat the last three steps with the back layer.
11. Let the textolite cool down: you can put the kettle on to warm up and begin to dissolve the ammonium persulfate.
12. Carefully peel off the excess paper from the cooled PCB (without water, this is extremely important). The toner should come off along with the glossy layer of photo paper, that’s how it was intended.

In case of mistakes, you can erase one of the layers with acetone, place the already torn piece of paper on the opposite layer (so that the toner does not come off the board and transfer to the board on which you are ironing) and repeat.

Textolite --> Textolite with tracks

For etching, we need a plastic container (or any non-metallic container in which the board will fit lying down). And also, a disposable spoon or varibashi for stirring the board (against bubbles that interfere with etching).

It is recommended to dilute ammonium persulfate in warm water 1:2. But this is a fairly high concentration, 1:3 or even 1:4 is enough. After all, you can stir it some more later. The recommended temperature for unwinding is 40-50 degrees.

However, keep in mind that overheating all kinds of chemicals is quite dangerous. High concentration, high temperature and copper salts can lead to creepy results.

The essence of manufacturing printed circuit boards using the laser-ironing method (IUT) is the thermal transfer of a printed circuit board printed on a laser printer onto foil PCB followed by etching in ferric chloride.

Development of a printed circuit board in the Sprint-Layout v program. 5.0

When making a double-sided board, the layers must be separated before printing on paper. This is done by duplicating the board, flipping it vertically/horizontally and removing unnecessary tracks on each layer. When copying, the distance between the boards should be one and a half centimeters. As a result we get:

Preparing a double-sided printed circuit board for printing in the Sprint-Layout v program. 5.0

I select “File-Print”. In the window that appears, I make the following settings:

I adjust the colors of the tracks (for layers M1 and M2 I set them to “black”).

I hide unnecessary layers (K1, K2).

I set the number of copies on the sheet (the “Copies…” button).

I set the print type to “Normal” (not “Mirror”).

Printing a board in the Sprint-Layout v program. 5.0

Paper - into the printer. I'm typing.

A few words about paper. For example, I take letterheads. Some people use photo paper to print on inkjet printers, others are pages from glossy magazines. Here you will have to experiment and choose the appropriate option for yourself.

If problems arise when printing, for example, some printers categorically do not digest “sweetheart”, or when printing on “thin” sheets they tear, then you can experiment with the type of paper in the printer settings. For example, I got normal printing on the “Film” type of paper.

I cut out one copy of the board.

Cutout of a printed circuit board

I combine the “holes” “for light”. I fold the paper. I check again that all the holes are positioned correctly (at the moment of “bending” the layers could shift).

Aligning board layers

I glue the free edge.

Making an envelope

I get something similar to an “envelope”.

Ready envelope

I also recommend this technology (making an “envelope”) when making single-sided boards - this will allow you to fix the PCB inside, and for a double-sided board, it will also allow you to correctly hold the layers relative to each other.

While the “envelope” is drying between the pages of some book, I prepare the textolite.

PCB size +5...7 mm on each side to the size of the finished board. This will allow you not to bother with cleaning the edges of the PCB (as a rule, this is where problems arise when translating tracks), as well as with the precise installation of the board inside the envelope.

I clean the copper of the PCB until there is no oxidation and a characteristic shine is obtained: depending on the condition of the PCB, first with coarser sandpaper, then with fine sandpaper. When making a double-sided board, I try to paw less with my fingers on the already cleaned opposite layer.

The next stage is degreasing the printed circuit board. Why do I take two pieces of flannel rag (I refused to use cotton wool because it leaves lint behind) - one is soaked in solvent, the other is dry. I degrease with a rag soaked in a solvent, gradually wiping and moving from one edge to the other (rather than in a circular motion) - this allows for better rinsing and less smearing of copper particles on the surface of the board. To ensure that no stains remain after the solvent, immediately after wiping with a “wet rag” I wipe the surface of the board dry.

Now everything is ready to transfer the tracks from paper to PCB. I prepare a workplace (I have a chair, there is a centimeter-long stack of newspapers on the chair), fill a container with cold water, turn on the iron and wait for it to warm up (3-4 minutes, the temperature is at maximum, I selected the temperature experimentally).

I insert the payment into the envelope. Look at the clearance so that the tracks do not “hang” over the edge of the board. I place the board on a stack of newspapers and press the iron flat against the board with sufficient force for about 10 seconds. This allows the toner to initially stick to the PCB. Then I set the iron on the “edge” and with the edge, slowly and with effort, I iron the board. The whole procedure takes 30-40 seconds. If the board is double-sided, I turn the board over and again smooth the opposite side “edge-wise”. Without allowing the board to cool, I throw it into a container of water (for me, if the board cooled “naturally,” it happened that the tracks partially stuck back to the paper).

The board cools down for about a minute. During this time, the paper gets wet and is washed off without difficulty. I'm checking what happened. If necessary, I eliminate visible short circuits with a thin awl. If the print turns out really bad, I wash off the toner with a solvent and move on to the “cleaning with fine sandpaper” stage.

I etch the board in ferric chloride. This is approximately 20-60 minutes depending on the freshness of the solution and its temperature. A more aggressive environment (hydrochloric acid + hydroperite) corrodes the toner. The weaker one - a solution of copper sulfate and salt - poisons for a long time.

After etching the board, rinse under the tap in cold water with laundry soap.

I haven't removed the toner yet. I check the board against the light for visible short circuits. I eliminate their presence using an awl.

I cut the board to size. I'm drilling holes. I use drills with a diameter of 0.6, 0.8, 1.0, 1.2, 2.5, 3.0 mm, depending on the technological purpose of the hole. I drill holes with a small hand-held 12-volt homemade drill.

Drilling holes

Due to the fact that some drills have been used for a long time, when drilling, an “influx” of copper appears along the edge of the hole. I eliminate it after drilling all the holes using a “null”, and use it to remove a certain layer of toner. I wash off the remaining toner with a solvent. The final touch is to lightly clean the tracks with fine sandpaper until shiny and coat the board with liquid rosin. Drying.

Finished PCB

I either do not tinning the tracks at all (the board is covered with rosin and does not have time to oxidize at the stage of assembling and debugging the device), or I do it at the time of soldering the elements.

After the device is assembled and debugged, I wash off the remaining rosin with a solvent and cover the board with clear varnish.