It seems that overclockers are approaching hard times. Manufacturers, as if by agreement, began to limit the possibility of overclocking their products. I don't know if this is for good or for bad. I am not a principled opponent of overclocking, but I am pragmatic about it. If there is any benefit from it, for God's sake. But from my own experience, I was convinced that overclocking by itself does not give much. Well, I overclocked my processor by 40%, overclocked the video card a little and... I saw almost no differences in real work, with the exception of processor temperature. It was 38, now it’s 52, I don’t know what, but not degrees. He shrugged and returned everything to its place. True, I have a fairly powerful computer even without overclocking. So, overclocking seems to provide only moral satisfaction. Yes, and this is debatable. Actually, what is the merit of an overclocker? Is it because he got a well-used processor or was he lucky with a specific video card?
But there have always been, are and will be people for whom it is not enough to buy good thing and just use it. So anti-overclocking measures from Intel, AMD, ATI and Nvidia can help direct the energy of people who feel itchy hands in a more promising direction.
Here I would like to note the articles “Everything you wanted to do by hand, but were afraid to ask...” and “HDD loading indicator”. They can be considered as the first signs of this, in my opinion, extremely promising approach.
There are even more of those who could repeat the finished development. The problem is technology. Making high-quality printed circuit boards at home is quite problematic, and ordering them from specialized companies is expensive and time-consuming. And some of the buzz is lost.
Media selection
As it turned out, only special film For laser printers. Any type of paper is not suitable. The film should be thin and have a paper backing. Expensive types of films have a special sublayer to firmly fix the image and are also unsuitable. IN Lately I use EMTEK film, because Xerox film has disappeared from sale here, but Xerox is better. It warps less when heated. It is better to use low-melting toner. At first I used the original Samsung ML-1250 toner cartridge. It provides a very good dense image. After refilling the cartridge with Xerox 8T toner, as I was advised at the service center, the image became worse and the boards stopped working altogether, which prompted me to do research. But, having improved the technology, I achieved excellent results and with this toner.
Preparation of the workpiece
For getting good result surface preparation of the workpiece is critical. The surface must be perfectly clean and smooth. Wiping with alcohol, acetone or any cleaning agents is not sufficient. The surface preparation procedure is as follows. First, we clean the surface from coarse dirt with Pemolux powder. We rinse the workpiece with a cotton swab without touching the surface with your fingers. Place it in a ferric chloride solution for 10-15 seconds. In this case, thin upper layer along with all the contaminants. We rinse the workpiece under running water with a cotton swab. Shake off the water and dry without touching the surface with anything. If everything is done correctly, the result should be a dark pink matte surface, possibly with slight streaks. The main thing is that there should be no shiny areas. If they are, repeat the procedure.
Rolling a pattern
It is usually recommended to place the workpiece, the carrier on it and iron it with an iron. Under ideal conditions, this is possible and will pass, but in reality both the surface of the workpiece and the sole of the iron are not completely smooth and it will not be possible to obtain uniform pressing of the hot medium to the surface of the workpiece. In addition, the process cannot be controlled and you have to rely on luck. So I fix the iron with the sole up, put it on it Blank sheet paper so as not to accidentally damage the sole and the workpiece on it. The iron should be heated to a temperature at which the paper does not yet turn yellow, but no less. I lay the film with the pattern on top and roll it with a special device made from the pressure roller of a tape recorder. Rolling should begin from the center, squeezing the air from under the film to the sides. After the film adheres tightly to the surface of the workpiece, we increase the rolling force and carefully go over the entire board. Remove the workpiece from the iron and cool it. You can remove the film from the workpiece only after it has completely cooled. If done correctly, all the toner will transfer to the board, leaving faint pinkish marks on the film. The film cannot be reused.
Pin a picture
Despite the fact that the design looks almost perfect in appearance, you cannot etch the board right away. The toner layer becomes porous. If you immediately etch the board and then look at the resulting conductors under a microscope or a strong magnifying glass, the etched points are clearly visible, and the edges of the conductor turn out to be uneven. To avoid this, cover the design on the board with a 10% solution of rosin in alcohol and place it on the iron again. The temperature should be set to the maximum so that the paper turns yellow and smokes. Let stand for 10 minutes. In this case, the toner fuses with rosin, forming a very durable, uniform, shiny layer. Let the board cool and develop the design with a swab of alcohol. Rosin fused with toner does not dissolve in alcohol, and the remains of unevaporated rosin from gap areas can be removed without much difficulty. When wiping, you can apply considerable force. The alloy of toner and rosin holds very firmly, even with sandpaper it is difficult to remove it. If somewhere the drawing is damaged, then this is its fate. It is better to detect a poorly rolled conductor at the wiping stage than after etching. If unsuccessful, wash off the drawing with acetone and repeat everything from the very beginning. This happens rarely.
Board etching
We carry out etching in a solution of ferric chloride. The solution can be heated to a temperature of 50-60 degrees. There are no special features. After etching, rinse the board with water and wash off protective covering acetone.
Results achieved
Using the technology described above, single-sided printed circuit boards measuring up to 100x150 mm were produced. The technology allows one conductor to be routed between the legs of microcircuits in DIP packages, so I have not yet encountered the need for double-sided boards. I have an idea about modifying the technology for double-sided boards, but have not tried it yet. The entire board manufacturing cycle takes about two hours, excluding the time spent on wiring. The payment is received on the first try in 9 cases out of 10.
P.S. This is my first article for you. If this topic is of interest to you, I will send more. I have a lot of materials.
Sincerely, S. Veremeenko.
We have a factory prototype board of this type at our disposal:
I don't like her for two reasons:
1) When installing parts, you have to constantly turn back and forth in order to first install the radio component, and then solder the conductor. It behaves unsteadily on the table.
2) After dismantling, the holes remain filled with solder; before the next use of the board, you have to clean them.
Searching on the Internet different kinds breadboards that you can make with your own hands and from available materials, came across a few interesting options, one of which decided to repeat.
Option #1
Quote from the forum: « For example, I have been using these homemade breadboards for many years. Assembled from a piece of fiberglass into which copper pins are riveted. Such pins can either be bought on the radio market or made yourself from copper wire with a diameter of 1.2-1.3 mm. Thinner pins bend too much, and thicker pins take up too much heat when soldering. This “breadboard” allows you to reuse the most shabby radioelements. It is better to make connections with wire in fluoroplastic insulation MGTF. Then, once made, the ends will last a lifetime.”
I think this option will suit me best. But fiberglass and ready-made copper pins are not available, so I’ll do it a little differently.
Copper wire extracted from the wire:
I stripped the insulation and, using a simple limiter, made pins of the same length:
Pin diameter - 1 mm.
I used thick plywood as the basis for the board. 4 mm (The thicker it is, the stronger the pins will hold.):
In order not to have to worry about markings, I taped the lined paper onto the plywood:
And drilled holes in increments 10 mm drill diameter 0.9 mm:
We get even rows of holes:
Now you need to drive the pins into the holes. Since the diameter of the hole is smaller than the diameter of the pin, the connection will be tight and the pin will be tightly fixed in the plywood.
When driving pins under the bottom of the plywood, you need to place a metal sheet. The pins are driven in with light movements, and when the sound changes, it means the pin has reached the sheet.
To prevent the board from fidgeting, we make legs:
Glue:
The breadboard is ready!
Using the same method, you can make a surface-mount board (photo from the Internet, radio):
Below, to complete the picture, I will present several suitable designs found on the Internet.
Option No. 2Push pins with a metal head are hammered into a section of the board:
All that remains is to tin them. Copper-plated buttons can be tinned without problems, but with steel ones. 
When making printed circuit boards at home, the simplest and most common method is the LUT method.
This method is not without its drawbacks. If the toner is heated weakly, it will not stick to the foil of the printed circuit board; if it is heated too much, it will be smeared. It is necessary to select the print quality; if there is a lot of toner, it will be smeared, and the tracks, at small intervals, may stick to each other. If the printed board is not heated well, some of the tracks will not be printed, this especially often happens in the corners of printed circuit boards.
I will tell you about a method for transferring a printed design onto foil without heating. The drawing will not be smeared, all the toner is transferred from the paper. To do this, you will need two cheap chemical components: alcohol and acetone.
Instead of acetone, you can use any other substance that dissolves the toner well.
Alcohol does not react with toner, anyone who has tried to wipe a printed circuit board with it after etching knows this, but it quickly evaporates. It is needed to dilute the acetone.
Acetone dissolves toner perfectly and also evaporates quickly. If you try to use it in its pure form, it will blur your drawing, as in the photo.
There will be some kind of mess on the printed circuit board.
In what proportions should acetone and alcohol be mixed?
You will need three parts acetone and eight parts alcohol. All this must be mixed and poured into some container with a tight lid. It is important that the container is not dissolved with acetone.
How to use the mixture?
Draw a small amount of the resulting mixture into the syringe,
Apply it to the future printed circuit board (not to the printout), which has been previously cleaned of oxides and well degreased (this is important). After that, put your printout on it. You don’t have to rush too much; the mixture does not evaporate instantly. Lightly press the paper so that it completely adheres to the board and is saturated with the solution,
Wait 10-15 seconds, you will see when the paper is saturated,
After this, press the paper firmly, pressing the paper strictly perpendicularly so that it does not move. Wait another 10-20 seconds. During this time, the toner will react with acetone, become sticky and stick to the board. Paper napkins blot the remaining liquid, wait until the paper dries, then dip the board in water so that the paper gets wet, and peel it off. All the toner will remain on the board, and the paper will be clean. After this, rinse the board to remove any remaining acetone. All. You can etch the printed circuit board.
In the photo, I removed the paper without soaking it in water and the toner remained in some places.
On the pages of the site there has already been talk about the so-called “pencil technology” for manufacturing printed circuit boards. The method is simple and accessible - a correction pencil can be bought at almost any store that sells office supplies. But there are also limitations. Those who have tried to draw a PCB drawing using a correction pencil have noticed that minimum width the resulting track is unlikely to be less than 1.5-2.5 millimeters.
This circumstance imposes restrictions on the manufacture of printed circuit boards that have thin tracks and a small distance between them. It is known that the pitch between the pins of microcircuits made in a surface-mount package is very small. Therefore, if you need to make a printed circuit board with thin tracks and a small distance between them, then the “pencil” technology will not work. It is also worth noting that drawing a picture with a correction pencil is not very convenient, the paths are not always smooth, and the copper patches for sealing the leads of radio components are not very neat. Therefore, you have to adjust the printed circuit board design with a sharp razor blade or scalpel.
A way out of this situation may be to use a PCB marker, which is perfect for applying an etch-resistant layer. Unknowingly, you can purchase a marker for writing inscriptions and marks on CDs/DVDs. Such a marker is not suitable for the manufacture of printed circuit boards - a ferric chloride solution corrodes the pattern of such a marker, and the copper traces are almost completely etched. But, despite this, there are markers on sale that are suitable not only for writing inscriptions and marks on various materials(CD/DVD discs, plastic, wire insulation), but also for making an etching-resistant protective layer.
In practice, a marker for printed circuit boards was used Edding 792. It allows you to draw lines with a width of 0.8-1 mm. This is enough to make large quantity printed circuit boards for homemade electronic devices. As it turned out, this marker copes with the task perfectly. The printed circuit board turned out pretty good, although it was drawn in a hurry. Take a look.
PCB (made with Edding 792 marker)
By the way, the Edding 792 marker can also be used to correct errors and blots that occurred when transferring a printed circuit board design to a workpiece using the LUT (laser ironing technology) method. This happens, especially if the printed circuit board is quite large sizes and with a complex pattern. This is very convenient, since there is no need to completely transfer the entire design onto the workpiece again.
If you can’t find an Edding 792 marker, it will do Edding 791, Edding 780. They can also be used to draw printed circuit boards.
Surely novice electronics enthusiasts will be interested in technological process making a printed circuit board using a marker, so this is what the story will be about next.
The entire process of manufacturing a printed circuit board is similar to that described in the article “Making a printed circuit board using the “pencil” method.” Here's a short algorithm:
About drilling holes.
There is an opinion that you need to drill holes in the printed circuit board after etching. As you can see, in the above algorithm, holes are drilled before etching the printed circuit board in the solution. In principle, you can drill either before etching the printed circuit board or after. From a technological point of view, there are no restrictions. But, it is worth considering that the quality of drilling directly depends on the tool used to drill holes.
If drilling machine develops good speed and there are high-quality drills available, then you can drill after etching - the result will be good. But, if you drill holes in the board with a homemade mini-drill based on a weak motor with poor alignment, you can easily tear off the copper spots for the terminals.
Also, a lot depends on the quality of PCB, getinax or fiberglass. Therefore, in the above algorithm, drilling holes occurs before etching the printed circuit board. With this algorithm, the copper edges remaining after drilling can be easily removed sandpaper and at the same time clean the copper surface from contaminants, if any. As is known, the contaminated surface of copper foil is poorly etched in solution.
How to dissolve the protective layer of the marker?
After etching in a solution, the protective layer, which was applied with an Edding 792 marker, can be easily removed with a solvent. In fact, white spirit was used. It stinks, of course, disgustingly, but it washes off the protective layer with a bang. There are no varnish residues left.
Preparing a printed circuit board for tinning copper tracks.
After the protective layer is removed, you can for a few seconds throw the printed circuit board blank into the solution again. In this case, the surface of the copper tracks will be slightly etched and become bright pink. Such copper is better covered with solder during subsequent tinning of the tracks, since there are no oxides or small contaminants on its surface. True, tinning of the tracks must be done immediately, otherwise the copper in the open air will again be covered with a layer of oxide.
Finished device after assembly
How to prepare a board made in Eagle for production
Preparation for production consists of 2 stages: technology constraint check (DRC) and generation of Gerber files
Each manufacturer of printed circuit boards has technological restrictions on the minimum width of tracks, gaps between tracks, hole diameters, etc. If the board does not meet these restrictions, the manufacturer refuses to accept the board for production.
When creating a PCB file, the default technology constraints are set from the default.dru file in the dru directory. Typically, these limits do not match those of real manufacturers, so they need to be changed. It is possible to set the restrictions just before generating the Gerber files, but it is better to do this immediately after generating the board file. To set restrictions, press the DRC button
Go to the Clearance tab, where you set the gaps between the conductors. We see 2 sections: Different signals And Same signals. Different signals- determines the gaps between elements belonging to different signals. Same signals- determines the gaps between elements belonging to the same signal. As you move between input fields, the picture changes to show the meaning of the entered value. Dimensions can be specified in millimeters (mm) or thousandths of an inch (mil, 0.0254 mm).
The Distance tab defines minimum distances between the copper and the edge of the board ( Copper/Dimension) and between the edges of the holes ( Drill/Hole)
On the Sizes tab for double-sided boards, 2 parameters make sense: Minimum Width- minimum conductor width and Minimum Drill - minimum diameter holes.
On the Restring tab, you set the sizes of the bands around vias and contact pads of lead components. The width of the belt is set as a percentage of the hole diameter, and you can set a limit on the minimum and maximum width. For double-sided boards the parameters make sense Pads/Top, Pads/Bottom(pads on the top and bottom layer) and Vias/Outer(vias).
On the Masks tab, you set the gaps from the edge of the pad to the solder mask ( Stop) and solder paste ( Cream). Clearances are set as a percentage of the smaller pad size, and you can set a limit on the minimum and maximum clearance. If the board manufacturer does not specify special requirements, you can leave the default values on this tab.
Parameter Limit defines the minimum diameter of the via that will not be covered by the mask. For example, if you specify 0.6mm, then vias with a diameter of 0.6mm or less will be covered by a mask.
After setting the restrictions, go to the tab File. You can save settings to a file by clicking the button Save As.... In the future, you can quickly download settings for other boards ( Load...).
At the touch of a button Apply established technology limitations apply to the PCB file. It affects layers tStop, bStop, tCream, bCream. Vias and pin pads will also be resized to meet the constraints specified in the tab Restring.
Button press Check starts the constraint control process. If the board meets all restrictions, a message will appear in the program status line No errors. If the board does not pass inspection, a window appears DRC Errors
The window contains a list of DRC errors, indicating the error type and layer. When you double-click on a line, the area of the board with the error will be shown in the center of the main window. Error types:
gap too small
hole diameter too small
intersection of tracks with different signals
foil too close to the edge of the board
After correcting the errors, you need to run the control again and repeat this procedure until all errors are eliminated. The board is now ready to output to Gerber files.
From the menu File choose CAM Processor. A window will appear CAM Processor.
The set of file generation parameters is called a task. The task consists of several sections. The section defines the output parameters of one file. By default, the Eagle distribution includes the task gerb274x.cam, but it has 2 drawbacks. Firstly, the lower layers are displayed in a mirror image, and secondly, the drilling file is not output (to generate the drilling, you will need to perform another task). Therefore, let's consider creating a task from scratch.
We need to create 7 files: board borders, copper on top and bottom, silkscreen on top, solder mask on top and bottom, and drill bit.
Let's start with the boundaries of the board. In field Section enter the section name. Checking what's in the group Style installed only pos. Coord, Optimize And Fill pads. From the list Device choose GERBER_RS274X. In the input field File The name of the output file is entered. It is convenient to place the files in a separate directory, so in this field we will enter %P/gerber/%N.Edge.grb . This means the directory where the board source file is located, the subdirectory gerber, original board file name (no extension .brd) with added at the end .Edge.grb. Please note that subdirectories are not created automatically, so you will need to create a subdirectory before generating files gerber in the project directory. In the fields Offset enter 0. In the list of layers, select only the layer Dimension. This completes the creation of the section.
To create a new section, click Add. A new tab appears in the window. We set the section parameters as described above, repeat the process for all sections. Of course, each section must have its own set of layers:
copper on top - Top, Pads, Vias
copper bottom - Bottom, Pads, Vias
silkscreen printing on top - tPlace, tDocu, tNames
mask on top - tStop
bottom mask - bStop
drilling - Drill, Holes
and the file name, for example:
copper on top - %P/gerber/%N.TopCopper.grb
copper bottom - %P/gerber/%N.BottomCopper.grb
silkscreen printing on top - %P/gerber/%N.TopSilk.grb
mask on top - %P/gerber/%N.TopMask.grb
bottom mask - %P/gerber/%N.BottomMask.grb
drilling - %P/gerber/%N.Drill.xln
For a drill file, the output device ( Device) should be EXCELLON, but not GERBER_RS274X
It should be kept in mind that some board manufacturers only accept files with names in 8.3 format, that is, no more than 8 characters in the file name, no more than 3 characters in the extension. This should be taken into account when specifying file names.
We get the following:
Then open the board file ( File => Open => Board). Make sure the board file has been saved! Click Process Job- and we get a set of files that can be sent to the board manufacturer. Please note that in addition to the actual Gerber files, information files will also be generated (with extensions .gpi or .dri) - you do not need to send them.
You can also display files only from individual sections by selecting the desired tab and clicking Process Section.
Before sending the files to the board manufacturer, it's helpful to preview what you've produced using a Gerber viewer. For example, ViewMate for Windows or for Linux. It can also be useful to save the board as a PDF (in the board editor File->Print->PDF button) and send this file to the manufacturer along with the gerberas. Because they are people too, this will help them not make mistakes.
Technological operations that must be performed when working with SPF-VShch photoresist
1. Surface preparation.
a) cleaning with polished powder (“Marshalit”), size M-40, washing with water
b) pickling with a 10% sulfuric acid solution (10-20 sec), rinsing with water
c) drying at T=80-90 gr.C.
d) check - if within 30 seconds. a continuous film remains on the surface - the substrate is ready for use,
if not, repeat all over again.
2. Application of photoresist.
Photoresist is applied using a laminator with Tshaft = 80 g.C. (see instructions for using the laminator).
For this purpose, the hot substrate (after the drying oven) simultaneously with the film from the SPF roll is directed into the gap between the shafts, and the polyethylene (matte) film should be directed towards the copper side of the surface. After pressing the film to the substrate, the movement of the shafts begins, while the polyethylene film is removed, and the photoresist layer is rolled onto the substrate. The lavsan protective film remains on top. After this, the SPF film is cut on all sides to the size of the substrate and kept at room temperature within 30 minutes. Exposure for 30 minutes to 2 days in the dark at room temperature is allowed.
3. Exposure.
Exposure through a photomask is carried out on SKTSI or I-1 installations with UV lamps such as DRKT-3000 or LUF-30 with a vacuum vacuum of 0.7-0.9 kg/cm2. The exposure time (to obtain a picture) is regulated by the installation itself and is selected experimentally. The template must be pressed well to the substrate! After exposure, the workpiece is kept for 30 minutes (up to 2 hours is allowed).
4. Manifestation.
After exposure, the drawing is developed. For this purpose, the top protective layer, the lavsan film, is removed from the surface of the substrate. After this, the workpiece is dipped into a solution of soda ash (2%) at T = 35 g.C. After 10 seconds, begin the process of removing the unexposed part of the photoresist using a foam rubber swab. The time of manifestation is selected experimentally.
Then the substrate is removed from the developer, washed with water, and pickled (10 sec.) with a 10% solution of H2SO4 ( sulfuric acid), again with water and dried in a closet at T=60 deg.C.
The resulting pattern should not peel off.
5. The resulting drawing.
The resulting pattern (photoresist layer) is resistant to etching in:
- ferric chloride
- hydrochloric acid
- copper sulfate
- aqua regia (after additional tanning)
and other solutions
6. Shelf life of SPF-VShch photoresist.
The shelf life of SPF-VShch is 12 months. Storage is carried out in a dark place at a temperature of 5 to 25 degrees. C. in an upright position, wrapped in black paper.
