PVC technology for printed circuit boards
In the amateur radio world there are a huge number of different technologies for making printed circuit boards, the fingers are not enough to count them all. The most popular ones in my opinion are: Lacquer “LC”, which is when the pattern is applied with a brush, quick-drying varnish to the printed circuit board. Laser-utilization technology “LUT”, design is printed on glossy paper by laser printer, then with a hot iron is transferred to textolite. And perhaps the most expensive “Photoresist” technology uses a special photoresist film on which the pattern is printed.
Today I want to tell you about a very simple and more economical PVC technology of making printed circuit boards at home, which I use more than 5 years. The picture is printed by a laser printer on a common cheap PVC film “Samokleika” which is sold in almost any hardware or construction store.
Well, let’s get down to business?
And so, to make printed circuit boards with PVC technology we need, PVC film “Samokleika” from a construction store. The most popular size is 45×800 cm, its per skein, from one skein you can make more than 1000 printed circuit boards, of course there are other sizes large and small, the choice of size is up to you, the are also different. The color of the PVC film is better to choose a lighter one, so that the printed on the laser printer can be seen better.
For printing small circuit boards not more than 10 cm wide, it is best to cut the PVC film into pieces of 10.5х29.This is half of an ordinary A4 sheet of paper.
It is also possible to cut a larger piece of PVC foil than the printed circuit board, then cut the edge of the backing paper to 0.5 cm and glue it to a sheet of ordinary paper measuring 10.5х29.5 cm. The paper will serve as a guide. Thus the consumption of the PVC film will be more economical and the thin PVC film will not get jammed in the printer when printed. I like this one the best.
To draw printed circuit boards and print tracks on PVC foil, I use a special program Sprint Layout 6.You can download the program here.
In the top left corner of Sprint Layout 6.0 program, click on the folder icon, an Explorer will open, indicate the path to the file with the printed circuit board in lay format and click on open.
Opens the image of the circuit board. Click on the printer icon.
Select image parameters in this window. Uncheck the “K1” layer.
In the parameters field put a checkmark “Mirroring”. You have to do it to have the right layout on the board, otherwise the tracks on the board will be vice versa.
In the middle tab we click on “Printer”.
Select the printing parameters in the window that appears. Set the sheet size “Envelope 0 (COM10). This format corresponds to the size of 10.5х29.5 cm. Click OK.
Printing a picture of the board
1) Printing a design on thermal transfer paper. You can buy such paper for example at Aliexpress where it costs mere pennies for 10 sheets of A4 paper. You could use any other glossy paper instead, for example from magazines. However, the toner transfer quality of such paper may be much worse. Some people use glossy Lomond paper, a good option if it were not for the price. such paper is much more expensive. I recommend that you try printing on different papers and then compare which one gives the best result.
Another important point when printing a picture. the printer settings. It is absolutely necessary to switch off toner savings and set the density to maximum, because the thicker the layer of toner, the better for our purposes.
Also it is necessary to take into account the moment that the pattern will be transferred to the textolite in the mirror image, so you should provide in advance whether it is necessary or not to unmirror the pattern before printing. This is especially critical on boards with chips, because you can not put them on the other side.
Preparation of the textolite for transferring an image onto it
2) The second step. the preparation of the textolite for pattern transfer. Most commonly textolite is sold in pieces of 70×100 or 100x150mm. It is necessary to cut a piece suited to the size of the board, with 3-5 mm margin on the edges. It is best to saw the textolite with a metal saw or a jigsaw, or, as a last resort, you can cut it with scissors. Then this piece of sandpaper has to be wiped with a fine sandpaper or a hard eraser. On the surface of copper foil are formed small-small scratches, this is normal. Even if the textolite initially looks perfectly flat, this step is necessary, otherwise it will be difficult to tin it later. After sanding, be sure to wipe the surface with alcohol or solvent to wash off any dust or greasy hand marks. Do not touch the copper surface afterwards.
Drilling
If you are using FR-4 as the base material, you will need tungsten carbide coated drills, drills from high speed steels wear out very quickly, although steel can be used for large diameter single holes (over 2 mm), t.к. Tungsten carbide drills of this diameter are too expensive. When drilling holes smaller than 1 mm in diameter, it is best to use an upright machine, otherwise your drills will break quickly. The top-down motion is the best way to apply load to the tool. Carbide drills are made with a rigid shank (t.е. drill exactly to the diameter of the hole), or with a thick (sometimes called a “turbo”) shank that has a standard size (usually 3.5 mm).
When drilling with carbide tipped drills it is important to have a hard grip on the BOP, i.e.к. the drill bit can tear off a piece of board on upward movement.
Drill bits of small diameters are usually inserted in either a collet chuck of various sizes or a 3 jaw chuck. sometimes a 3 jaw chuck is the best option. For precision fixing, however, this fixture is not suitable, and the small drill size (less than 1 mm) quickly makes grooves in the clamps that ensure good fixing. That’s why it is better to use a collet chuck for drill bits smaller than 1mm. Just in case, get an extra set with spare collets for each size. Some inexpensive drill bits are made with plastic collets. throw them out and buy metal ones.
A good work station is needed to achieve acceptable accuracy, i.e.е., first, provide lighting for the board when drilling. You can use a 12V halogen bulb (or 9V to reduce brightness) attached to a tripod to be able to select the position (illuminate the right side). Second, raise the work surface about 6″ above the height of the table, for better visual control of the process. It is not a bad idea to remove dust (you can use a normal vacuum cleaner), but it is not necessary. accidental circuit shorting by a dust particle is a myth. It should be noted that fiberglass dust from drilling is very prickly and causes skin irritation if it comes into contact. Finally, it is very convenient to use the foot switch of the drilling machine when working, especially with frequent drill changes.
Typical hole sizes: Transition holes. 0.8 mm or less Integral circuit, resistors, etc.д 0.8 mm. Large diodes (1N4001). 1.0 mm; Contact pads, grass trimmers. from 1.2 to 1.5 mm;
Try to avoid holes with a diameter of less than 0.8mm. Always keep at least two spare drill bits 0.8 mm, t.к. they always break just when you need to make an order in a hurry. Drills of 1 mm and larger are much more reliable, although it is advantageous to have spare ones for them too. When you need to make two identical boards, you can drill them simultaneously to save time. Be very careful to drill holes in the center of the contact pad near each corner of the PCB, and for large boards, holes close to the center. So, put the boards on top of each other and drill the holes 0.8 mm in the two opposite corners, then, using the pins as pegs, secure the boards relative to each other.
electrolysis
Solution: 10 gr. of copper sulfate dissolved in 100 ml. add 1cm3 (=1ml) of sulfuric acid (electrolyte for lead car batteries) = sulfuric acid solution
RV-T glittering additive if possible.
Capacity: in the middle of the cathode. MINUS (our board), moves left / right (arduina servo motor on the plastic insides of the CD ROM) on the sides of the anode. this is PLUS.
Give a current of 2A per 1dm2 of board. My first electrolysis setup looked like this:
The electrolyte lives a long time, the main thing is to keep it clean (filter it through cotton pads or gauze). I keep the electrolyte in a regular plastic food container (can be stored anywhere).
It is impossible to use the stove for cooking, of course. I heated the board on the stove and inexperienced overcooked it until the board was softened. the stench was awful. I had to buy a regular heater 25 (up to 250 C) and immediately the process went in the right direction. The result after 10 minutes of electrolysis. Unfortunately MINUS was only on one side of the board (the second was without potential), but I must admit that everything is very encouraging:
holes 0.4mm
As a result, we must conclude that the copper in the holes is deposited, although not evenly enough (there are noticeable gaps).
An unnecessary effect is also the deposition of copper on the entire flat surface of the board, increasing the already sufficient copper thickness 0.35mm. The thing is that the copper is consumed quite intensively and the Anode is disappearing before our eyes.
Maybe it makes sense to cover everything with a mask of something and leave only the holes?
Carbide Drill Bit Set 0.5-0.9mm, a little review on the
As a lyrical digression, I will say that by and large you can drill printed circuit boards even with a sharpened nail or needle, in fact, I even had to do it. Of course it’s not very comfortable, but it’s realistic. After that I quickly switched to the usual thin drills, although I made attempts to start using carbide drills, but about that a little later, but for now let’s move on to the review.
Drills in the store are available as a set.1. 0.50.60.70.80.9mm. ref2. 0.250.30.350.40.45mm. link
I chose the first option as the most commonly used.
The drills come in a pretty handy box.
The cover is fastened with something like a hinge, it runs pretty tight, at least until it’s new. In general, I am used to store drills in less convenient, but more compact conditions, so for me this option was a bit unusual, but I liked it 🙂
In total there are 50 drill bits, 10 of each diameter.
Each drill has a respective marking in the form of a plastic stop ring.Purple. 0.9mmOrange. 0.8mmWhite. 0.7mmBlue. 0.6mmBrown. 0.5mm
As I wrote above, the drills have color differentiation of pants marking, but in addition to that, each drill has a numerical marking of diameter. For some reason, though, the markings on the different drills are slightly different.
One of the advantages of such drills, like milling cutters, is the standard diameter of the shank, that allows to use either a collet or a chuck of the same diameter.In this case, the diameter of the shank is stated as 3.The 175mm is probably one of the most popular among small CNC machines.
My measurement showed a diameter of 3.17, but I measured it with a caliper and its resolution (and accuracy) is simply insufficient to perform such measurements. But the diameters of the cutting part are slightly understated, by about 3 hundredths of a point, all equally one way, so I can’t say if it’s a measurement error or designed that way, I tend to think it’s the second one.In fact, this is not critical at all, since these 2-3 hundredths will still be obtained during drilling due to runout.
But the length has a noticeable difference. Here I have shown the two most extreme variants, the rest of the drills “float” somewhere in between.I have not used drill bits with plastic markers before, but for some reason I thought they were necessary and as a stop to always set the drill to a fixed drilling depth.
Some more photos of the drills and their cutting parts.First, the drill of the largest diameter, 0.9mm
The sharpening is pretty good, but a little different from what I’m used to.
There is a small dents in one of the cutting edges, but in this case it is not too bad. I didn’t choose separate drill bits for the photo, just took the first ones with outside diameters at random.
Sharpness is even, or to tell more correctly, symmetric, which is very important, because if it is sharpened incorrectly, it is not only more likely to break the drill bit (in this case), but if it does not break, it may result in a larger diameter hole.I looked at all the drills, all are sharpened symmetrically and equally.Here is a picture of a 0 diameter drill bit.5mm.
I use ordinary drills, but a long time ago I bought a dozen of carbide drills of home manufacture to try them out. The first difference is the diameter of the shank, it is smaller than the reviewed ones.
But all my attempts to use such drills led to the fact that literally after a dozen holes they simply broke. If an ordinary drill breaks only under heavy loads, the carbide drill is much more brittle, this is the price for increased hardness and a longer service life.Actually therefore, such drills with manual drills are contraindicated, the result can be seen in this photo: (No matter how firmly you hold the microdrill, runout and slopes are still inevitable, so in this application should use a simple drill bit.
But a closer look revealed another rather important difference. Domestic drills have such a concept as “ribbon”.
You can see it in this drawing. Ribbon makes cutting easier and reduces the load on the drill bit by not rubbing the entire plane of the drill bit against the material to be cut.
The same tape is present on the large drill bits, so the reviewed drills are a bit “simplified”, the domestic ones are essentially a reduced copy of the large drill.
But sharpening the domestic ones is easier than the reviewed ones. Transverse edge (place of convergence of cutting parts) is wider than the Chinese, so to cut and center such a drill will be worse than the Chinese.
PRINTED CIRCUIT BOARDS WITHOUT ETCHING
About 10 years ago, when I just started in electronics, I had to assemble a breadboard model on cardboard, I did not have a collet breadboard yet. Once the layout was working on cardboard, it had to be transferred to a printed circuit board and the board had to be etched in chlorine iron. This process is not quite simple for beginners, it has its own subtleties, I wanted to make devices on boards without etching. I found a way to make simple boards by grooving.
There are two varieties of this method:
The way of milling. Printed mounting pattern is put on the foil gethinax, and the printed mounting should be designed with narrow punched areas (their width should be equal to the diameter of the boron). Metal foil is removed from the blank spaces with a mill (bur) fixed in a chuck, sitting on the axis of the electric motor. After milling, the board is ground with a fine sandpaper, drilled holes in it and trimmed.
Cutting foil. In that time I made, among other things, one device on a DIP microchip:
Then do the following: let’s say we have a drawing of a divorced printed circuit board, even if the dimensions are not specified, trim it if needed in the graphical editor. Copy to microsoft word, adjust the size of the circuit board picture so that the parts on the board correspond to their actual size, for this click in word the “Preview” icon, attach a sheet and adjust the scale of a real A4 sheet.
So, we have achieved that the parts in the drawing are life-size (and the board, of course, also), we print them out on the printer. When preparing for printing it is convenient to put on one sheet of paper the circuit diagram, a printed circuit board in enlarged size and several blanks. life-size copies of the board.
I hope it’s not too complicated. After that we cut out the real size of the board with scissors, saw off with a hacksaw or cut with metal scissors a piece of textolite corresponding to the size of the board. Glue the pieces of electrical tape cut out on the board so that the copper foil is on top. After it is possible at once on a piece of paper, the accuracy of holes will suffer, to core or to mark places of the future holes under details with an awl. I immediately recommend to mark and drill the fastening holes of the board to the device case, after you solder the parts to the board it will not be so easy to drill. So we have all the holes tapped, but in principle you can drill them at this stage at once. Next, for which we printed out the board in an enlarged size, we take a pencil and “outline” by separating a line in the figure all the pads connected by a track from the other tracks, and the lines should be straight.
And start with the smallest tracks, then the middle ones, as a result, when we separate them we have the largest track, which would have to “outline” the longest will be “outlined” by itself. The fixing holes will also have to be “outlined”. For what purpose we do this? Along these lines in the future there will be grooves, which we will make, after we remove the drawing from a piece of textolite, with this cutter:
It is made from a hacksaw blade on an emery machine. The tinfoil should be cut all the way through to the end, so that you can see the textolite. So we have cut grooves and we have all the tracks separated from each other and from the mounting holes with a groove. The point of all this is to make sure that there is no contact between the different tracks, this is important!
After that we take the tester, set it to the sound dialling mode, and by touching them one by one the neighboring areas, check their connection, if there is a beep, it means the foil is either not cut through to the end, or the piece of wood shavings closed the neighboring areas. We can’t start soldering until we are sure about this! After that we take the alcohol, wipe the places around the holes where the contacts will be soldered and solder. This method with some experience can also be used for SMD parts. Here is a picture of one device board made with this method:
Have a good soldering! The material was prepared by: AKV.
Forum for discussion of printed circuit boards without etching
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A SIMPLE AND CHEAP WAY TO ETCH CIRCUIT BOARDS
Hi all! In this article I will tell you the easiest and cheapest way to etch boards at home using this technology. For this we will need:
As you can see, all components are available to everyone. You can buy hydrogen peroxide at the drugstore, and citric acid and salt at the grocery store. Everything will cost quite cheap. not more than 100.
Now we proceed to the preparation of the solution. To do this, we need to find some plastic container the size of the board. I used a regular plastic tray.
Pour hydrogen peroxide into the tray, then pour citric acid and salt. Mix it all up. We can consider that the solution is ready. Before we dip the circuit board into the solution we need to check that everything is okay. Exactly how the tracks are applied. To do this, take the template that has been applied to the board and the board itself and compare the picture. If there are places where the tracks are broken, you need to take a marker or varnish and finish them. The main thing is that the marker is indelible. You can check it by putting permanent marker on it. I advise to pay special attention to this, because if it is just a regular marker it does not work.
After examining the board, dip it into the liquid. Nothing happens at once, we need to heat the solution to etch the board quickly. For this we take a pot of water and carefully submerge the tray in it so that it does not overflow. And then we heat it all on the stove. When the solution heats up (about 50 degrees), it will react, you will see that bubbles are released.
The etching process itself takes about 15-20 minutes, and can take over an hour if you do not heat it. When you see that all the tracks are etched, carefully remove the board and wash it under the faucet. We pour out the solution, because it will not work anymore.
In the end we have a pretty good printed circuit board, in the photo the board is not quite worked out because of the bad pattern. If you do it right you will have a better result.
The finished device with this board (guess what it is)
As you can see this is the cheapest and most accessible way of etching boards. The only disadvantage is that the solution is disposable, ie every time you need to make a new solution. Good luck to you all. Kirill.
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Simple machine for drilling printed circuit boards.
The easiest way to drill PCBs by holding a motor with a mounted drill chuck in its hands. than once the drills broke, and every radio amateur scolded himself in his thoughts, and the next time when making a “printout”. Definitely wanted to change something in the process. Everyone decides for himself whether to make something from hand-made tools or buy ready-made. It all depends on the place of residence of the radio amateur. For example in the countryside away from major centers, the best way out of this situation is to make a machine tool with their own hands.
The main requirement for such a machine, it is that he could cope with his task, well, in its manufacture did not require complex lathe parts, as not everyone has access to a lathe. I offer you a simple design of a drilling machine for a home workshop, which I saw on the “Internet”, and which can be repeated at home is not particularly difficult. The author of this design, unfortunately, I do not know, and if it will appear, it will be happy to specify here his name and express gratitude for the simple construction. Machine tool dimensions; base 140×90 mm, height 150 mm. With its task he can handle it quite well and on the desktop takes up very little space. At this size it allows to drill holes in boards up to 150-170 mm wide. (the length of the board is not limited), which is quite sufficient in hams practice.
The base of the machine is made of any material at hand, at least 6-8 mm thick. You can use textolite, getinax, metal, plywood. If you take plywood, it is better to use not less than 10 mm thick. The dimensions of the base are shown above, but you can change these dimensions to suit your needs, both the base and the other parts. In the future I will simply specify my dimensions. The whole structure is going to be assembled on a U-shaped support, for which you need to take thick material, so that the entire structure does not spring and has sufficient strength.
This design uses a strip of metal, 25 mm wide. and a thickness of 4-5 mm. The total length is 140-150 mm. It is bent U-shaped, the attachment to the base is 30mm, the height is 40mm and the remaining is the length of 70-80mm. Three holes are drilled in the stand, one at the bottom to fix it to the base and two at the top for the vertical pins. The long pin is 100 mm long, diameter 5 mm.
A spring is put on the long pin. The short pin is threaded on both sides, for attaching the pin to the rack and on top for the locknut. The moving part with a motor mounted on it moves on these two pins. The spring must be stiff enough to lift the weight of the moving part with the motor.
The moving part is made of a strip of metal, at least 1.5-2.0 mm thick, 20 mm wide. The total length of the strip 100 mm, the dimensions of the folds 20x40x40 mm. Drilled a through hole for a thick pin and a hole for a thin pin. By the way, the pins can also be made of the same diameter, the main thing is that the material must be rigid enough, such as rollers from dot matrix printers. Motor mounting clamp. The spring is made of aluminum sheet, according to the diameter of the existing motor. I have the motor used for the DPM-30 machine.
To power such a motor it is enough to use a 12 volt source, and most importantly, you need to make a circuit to control the motor. This is so that without a load, the motor slowly rotates and when the drill touches the board. started to work at full power. There are a lot of layouts like this, for example you can choose from here. In my opinion it is better to assemble the last one. Although, why sin to hide, I still use without such a scheme, I have adjustable power supply and in pauses just remove the voltage.
Lever with holder, the construction can be clearly seen in the photos. Fix it in the holder and fasten to the stand.
Fasten the moving part and tighten the nut.
That’s all, now you have to fix the whole structure on the base, fasten the available motor with a clamp on the moving part, fasten the drill and start working. Yes, from my wife “confiscated” a time-worn cork base for hot dishes, and cut out the nozzle for printed circuit boards from it and glued it to the base, this is so that when you drill the circuit boards, the drill does not reach the base.
Good luck in your endeavors and all the best!
P.S. Yes, I also want to say a little bit about drills. Don’t be lazy and find yourself a special drill bit for drilling fiberglass. Our drill bits are made of VK6M alloy, they usually have the same diameter shank and drill bits themselves 0.7-2.0. The holes made with them are much nicer than those made with regular drills and they look like this;
The imported ones also look like this. This is not for the sake of advertising, but for convenience and enjoyment of work. I drilled the boards first with regular drills (metal), which after a few holes get very blunt, and after a dozen. come in complete disrepair, then I learned about these drills, found them and bought (their price, by the way, is within 20-50 re). I tried to drill with them. It’s a piece of cake. According to feedback from radio amateurs. One drill bit can drill for several years (several thousand holes) until it breaks because of careless handling.
But, these drills are not suitable for handheld drills. When trying to make a hole with them. it breaks in no time (because of the slightest misalignment). That is, they can be long and reliably drilled only in the machine, and the chuck must not have any runout, and the drill clamped to them must be well centered. Then their durability is also guaranteed.
Drilling machine for circuit boards with my own hands
Drilling holes in circuit boards is a long and laborious process that requires a high degree of accuracy, because the quality of the holes will depend on the quality of the circuit board. I am tired of drilling boards with a manual electric drill, so I decided to make a small drill press specifically for circuit boards. We wanted to make the design of the machine as simple and reliable as possible, so that it could be made by any radio amateur. So without thinking twice I developed a simple and very reliable design of a miniature drilling machine for printed circuit boards, the drawing of which is shown in this figure.
The drawing of the drilling machine for printed circuit boards
The parts for the drill press can easily be made on a lathe or with a turner I know. The base of the machine is a rectangular piece of wood chipboard, size 160×200 mm. I took the electric motor for the drilling machine from an old inkjet printer.
The collet chuck for fixing the drill bit I bought on Alike. If you order a chuck please pay attention to the diameter of the motor shaft, because shafts come in four sizes 2.35 mm, 3.17 mm, 4.05 mm, 5.05 mm, so the diameter of the chuck must fit the exact diameter of the shaft. Blago in China these things in bulk. Included with any chuck included five collet adapters for different drills which diameter 0.5 mm, 1 mm, 1.5 mm, 2.5 mm, 3 mm.
To drill holes in circuit boards it is best to use the special carbide drill bits made in Japan, bought in China on Alike. Diameter of the shank 3 mm, diameter of the working part of the drill 0.9 mm. As practice shows this is the most universal size of holes suitable for most radio components.
To supply the motor and the LED light a simple 12 volt power supply consisting of a transformer, four diodes and a capacitor. It is hidden under a metal cover, which has a switch to turn off the mains supply for a 220V transformer.
The power supply circuit for a drilling machine consists of four diodes IN4007 and a capacitor 1000mf 25V. So that there should be no problems with radio components. Any low-power 12V transformer 0.5А. The LED light is connected in parallel to the motor terminals. I used a small rectangular LED panel as a light source.
Schematic diagram of a power supply for a drilling machine
To make it look neat I decided to make a printed circuit board.
The circuit board of a power supply for a drilling machine
The feed mechanism is very simple. When the lever is pressed, the board rises and thus the holes are drilled. Of course we could make it with the top feed, like in conventional drill presses But why complicate the construction? Everything works fine as it is. The machine is 100% successful. Recommended at!
I recommend watching the video on how to make a drilling machine for circuit boards with your own hands
Friends, I wish you luck and good mood! See you in new articles!