سلام دوستان عزیزم
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Circuit boards produced with the screen printing technique
Note: The development time of silk and dried here exposed cards, changes depending on the quality of the ink, the type of bulb that uses light and away, exposing the cards. We recommend testing to find the time that it takes, both revealed, as the drying of paints, as things that get in your country.
Materials
Silk 90 120 y su respective frame the frame-T300
90% emulsion national universal atlas green and revealing 10%
Solvent (activator) PREGASOL EP 3
floral foam (oasis)
1 glass of 4 5 will mm to them same dimensions he unterior his frame.
Painting antisoldante ( welding mask UV )
Ink UV blanca y green paint to metal, polyethylene (timpes) screen line
1 plastic spatula (Racleta RASER) (waste them acrylics)
Hypochlorite Varsol to had given the
ferric chloride paint
Thinner
colophony resin
Caustic Soda
Chlorine domestic servant
plastic container suitable for him to shower them
Rayo UV bulb Card photoflood
Trozos y canvas burlap
NOTE : Original inks used in the manufacture of printed circuit boards in the stores get them Microcircuit so in TAIYO America .
The screen is a very old technique, which allows printing images on any material. Basically transferring an ink through a silk mesh tempered in a wooden frame. Silk has been pretreated with an emulsion which blocks the passage of the ink in the areas where no image, leaving free the area where the ink will pass. This printing system is used to print many numbers, without losing definition.
production technique of silkscreen printed circuits used industrially, because you can get very good quality print at very low cost. Once you have revealed silk frames or more known as racks, you can make multiple copies of the same design. This allows mass production of printed circuits. Although it is still a manual process this technique is one of the most used, as it allows work to quality and presentation necessary for prototyping electronic and / or industrial applications.
The frame
The frame is a wooden frame built with strips of 3 x 3 inches, perfectly square, which supports a fine silk, very warm and wrinkle, that by placing a flat copper supports evenly. The silk should be very warm and smooth. This silk is glued to the frame using a stapler, reinforcing it with masking tape and glue. It should be three racks, one for the PCB with 120 silk threads, and that the more detail is required, the number of threads should be higher. The second frame is for the mask and the third component to the solder mask ( solder mask UV ), this should be 90 threads. In this tutorial, comfort and practicality, we use a frame of 120 threads to make three impressions.
Applying the emulsion
After the racks have ready, in a room where there is too much light between, with the aid of a thin spatula, mixed 9 parts of emulsion 1 dichromate or developer, to obtain a uniform mixture. Mix it slowly, because if you make bubbles, can damage developing. After obtaining a uniform mixture is spread across the tissue using an emulsifier, such as that shown in the photograph, apply three emulsion layers, a layer on the rear side of the frame and two the front. The emulsion should be applied evenly over the silk, bearing in mind that there are no gaps or bubbles Uncoated.
Failure to get a cappuccino, you can use a squeegee or squeegee, which is nothing but a spatula width frame, with rubber. You can make the edges spatula recycling leftover thick acrylic sheets.
Then dry your silk emulsion using a hair dryer to help minimize drying time. remember that the emulsion is light sensitive, so you must make the process as quick as possible.
To view larger picture and to observe in detail click on it.
After drying the emulsion are placed acetate, or acetates in this case, with designs printed on the silk, by the rear of the frame and fixed with transparent adhesive tape. All acetates go backwards, ie, on the opposite side of the form will look when it's done. Be very careful in this process, since it depends on the circuit boards that fit well or tap rework, material and time wasting.
To make the acetates with printed circuit design, mask components and solder mask, should be printed in a place where burning machine with photomechanical plates . Do not serve in laser printer, because if it is not a good quality printer, the drawings are with pores.
If you are in Bogota Colombia, we recommend sending in Tecniartes print their acetates, in
Developing of the emulsion
Now we turn to the frame, I put a thin foam that can be jumbolon 3 mm, then we put a glass covering all silk and finally we put weight on it and thus prevent a separation between the acetates , silk, foam and glass.
All this is revealed on a table that can be built with a wooden box, which he placed on the bottom, about 50 inches from the glass top, a reflector, a bulb rays or ultraviolet light UV . This can be a reflector bulb street 250W .
expose the set, frame, acetate and glass to light for 13 minutes , no more, no less. In the case of not having a reflector, silk can be exposed to the light of a lamp or high intensity bulb, using a bulb ( Photoflood ) to 15 inches away, for a time of two minutes and a half. Be careful with the heat.
After exposing the frame to light, silk cover and immediately took her to a source of pressurized water, to wipe it from both sides. After a few seconds is observed as silk reveals the printed circuit pattern, as the emulsion falls in the areas where the light is not entered by the covering giving acetate. The developer is identical, as designed.
After processing the silk dry it with the hair dryer for 10 minutes and you're ready to print as many cards we want. The drying of the emulsion is characterized in that the brightness decreases when dry.
Cutting the Bakelite
Bakelite proceed to cut the printed circuit size, taking into account a small drop of about 5 millimeters edge serving as leeway printing. Bakelite must be heated before cutting to facilitate cutting and prevent splitting. In the photo appreciate semi industrial shears which cuts the material. We did not have one of these, you can use a sharp chisel and a metal ruler and check off several times, until the court Bakelite.
Printing on Bakelite tracks
Place the frame on a flat, hard, smooth, with a few presses fixing hinge, allowing easily lift without running position. Bakelite placed just below the printed circuit pattern with tracks and adjust with tape or placing stoppers Bakelite built the same, so no smudging when printing site. Place the frame on top of Bakelite, leaving at least about 5 millimeters up of Bakelite, you can use a small piece of wood. Then we apply the ink UV or failing paint polyethylene, off the silk, making a way in the part before the drawing, and then draw the spatula ( squeegee or squeegee ), the design of the printed circuit on the surface of the cards. This process is not easy the first time and must practice until you form that perfect.
[hide]
Notice how it should be printing. It must be flawless, landslides or damage the printed spots.
After making all desired impressions is necessary to clean the accumulated ink silk because otherwise it would plug silk, spoiling. For this we use a tow varsol and clean silk. If you want to remove the PCB silk and enable it for another design, use chlorine or thinner to remove the circuit embodied in silk.
now proceed to the cards let dry before proceeding with development.
Stoving
The inks suitable for printing on Bakelite, are those that are not rolled or when immersed in acid card developer. In industry manufacture of printed inks are used to dry the exposure of UV rays, for its high resistance to solvents. For this we must make a UV oven, which can be manufactured in a home using a reflector street about 400W to 500W , and a metal box, but in this case we see that is wooden and has no problems. The bulbs used in outdoor lighting reflectors, emit ultraviolet rays in small quantities. These are sufficient to dry the UV paint. Should be left at least one printed Bakelite 10 minutes in the hormone. Before turning to the development of copper.
Copper corrosion of printed cards
Once dry the ink cards comes to bathe in ferric chloride. A container can be manufactured as the one shown in the picture, which uses a small electric pump, which maintains the moving ferric chloride.
corrosive action of ferric chloride acts on surfaces that are not covered by ink, thereby obtaining the circuit printed. If not able to make a developer like this, you can use a plastic bucket and shake hands with chloride with only one card at a time, until it has lost the excess copper and proceed with the next card.
When we see that all the excess copper has been removed from the card, remove from ferric chloride and proceed to remove the ink tracks protected from corrosion, washing first with water card, removing ferric chloride, then dipped in caustic soda dissolved in water for one minute and brush until all the paint has fallen. subsequently washed again with water, to remove the caustic soda. Dry well cards.
If the steps above are done meticulously, you get a card or PCB quality and presentation.
Drilling
Then holes are drilled all the cards, using a drill or a mototool tree. Bits should have different calibres, and that the legs of the components have different diameters[/hide].
Printing the antisolder on Bakelite
The solder mask ( Solder mask UV ) applies on the ski, in the same manner as the process used to apply paint to prepare printed circuit tracks. This painting is expensive. Protects copper tracks, rust and possible short circuits, also adding to form a very good presentation.
An economical way to do is paint mixing solder Dielectric Layer with a few drops of green vegetable dye. After applying the paint, using the frame that previously did with the corresponding acetate, dried, using a furnace ultra violet (UV).
The paint is dried antisolder UV, so the cards should bake 10 minutes.
To view larger picture and to observe in detail click on it.
Components printing mask
To print the mask components, each card is placed on the opposite side of the tracks and previously with the frame with acetate disclose this mask, draw with UV paint, ink, polyurethane or polyethylene white all cards, given that the holes must match the card with the drawings of the components.
The paint used industrially to make the mask component is also UV-drying, so the cards should bake 10 minutes. If your budget is low, you can use polyurethane paint, which is very strong, although not as much as the UV paint. But you can get an acceptable result with this painting.
Now that we have finished printed circuits, we apply on the side of the tracks, a mixture of rosin resin and thinner, to prevent oxidation of the tracks of copper, in addition to giving a finished platelet brighter. Also when welding, reduces the surface tension of tin and the melting temperature, thus avoiding deterioration of the components and terminals. This mixture is called contacflux .
After making all desired impressions is necessary to clean the accumulated ink silk, otherwise it would plug silk, spoiling. For this we use a tow varsol and clean silk. If you want to remove the PCB silk and enable it for another design, use chlorine or thinner to remove the circuit embodied in silk.
Note: The development time of silk and dried here exposed cards, changes depending on the quality of the ink, the type of bulb that uses light and away, exposing the cards. We recommend testing to find the time that it takes, both revealed, as the drying of paints, as things that get in your country.
Materials
Silk 90 120 y su respective frame the frame-T300
90% emulsion national universal atlas green and revealing 10%
Solvent (activator) PREGASOL EP 3
floral foam (oasis)
1 glass of 4 5 will mm to them same dimensions he unterior his frame.
Painting antisoldante ( welding mask UV )
Ink UV blanca y green paint to metal, polyethylene (timpes) screen line
1 plastic spatula (Racleta RASER) (waste them acrylics)
Hypochlorite Varsol to had given the
ferric chloride paint
Thinner
colophony resin
Caustic Soda
Chlorine domestic servant
plastic container suitable for him to shower them
Rayo UV bulb Card photoflood
Trozos y canvas burlap
NOTE : Original inks used in the manufacture of printed circuit boards in the stores get them Microcircuit so in TAIYO America .
The screen is a very old technique, which allows printing images on any material. Basically transferring an ink through a silk mesh tempered in a wooden frame. Silk has been pretreated with an emulsion which blocks the passage of the ink in the areas where no image, leaving free the area where the ink will pass. This printing system is used to print many numbers, without losing definition.
production technique of silkscreen printed circuits used industrially, because you can get very good quality print at very low cost. Once you have revealed silk frames or more known as racks, you can make multiple copies of the same design. This allows mass production of printed circuits. Although it is still a manual process this technique is one of the most used, as it allows work to quality and presentation necessary for prototyping electronic and / or industrial applications.
The frame
The frame is a wooden frame built with strips of 3 x 3 inches, perfectly square, which supports a fine silk, very warm and wrinkle, that by placing a flat copper supports evenly. The silk should be very warm and smooth. This silk is glued to the frame using a stapler, reinforcing it with masking tape and glue. It should be three racks, one for the PCB with 120 silk threads, and that the more detail is required, the number of threads should be higher. The second frame is for the mask and the third component to the solder mask ( solder mask UV ), this should be 90 threads. In this tutorial, comfort and practicality, we use a frame of 120 threads to make three impressions.
Applying the emulsion
Failure to get a cappuccino, you can use a squeegee or squeegee, which is nothing but a spatula width frame, with rubber. You can make the edges spatula recycling leftover thick acrylic sheets.
Then dry your silk emulsion using a hair dryer to help minimize drying time. remember that the emulsion is light sensitive, so you must make the process as quick as possible.
To view larger picture and to observe in detail click on it.
To make the acetates with printed circuit design, mask components and solder mask, should be printed in a place where burning machine with photomechanical plates . Do not serve in laser printer, because if it is not a good quality printer, the drawings are with pores.
If you are in Bogota Colombia, we recommend sending in Tecniartes print their acetates, in
Developing of the emulsion
Now we turn to the frame, I put a thin foam that can be jumbolon 3 mm, then we put a glass covering all silk and finally we put weight on it and thus prevent a separation between the acetates , silk, foam and glass.
All this is revealed on a table that can be built with a wooden box, which he placed on the bottom, about 50 inches from the glass top, a reflector, a bulb rays or ultraviolet light UV . This can be a reflector bulb street 250W .
expose the set, frame, acetate and glass to light for 13 minutes , no more, no less. In the case of not having a reflector, silk can be exposed to the light of a lamp or high intensity bulb, using a bulb ( Photoflood ) to 15 inches away, for a time of two minutes and a half. Be careful with the heat.
After exposing the frame to light, silk cover and immediately took her to a source of pressurized water, to wipe it from both sides. After a few seconds is observed as silk reveals the printed circuit pattern, as the emulsion falls in the areas where the light is not entered by the covering giving acetate. The developer is identical, as designed.
After processing the silk dry it with the hair dryer for 10 minutes and you're ready to print as many cards we want. The drying of the emulsion is characterized in that the brightness decreases when dry.
Cutting the Bakelite
Bakelite proceed to cut the printed circuit size, taking into account a small drop of about 5 millimeters edge serving as leeway printing. Bakelite must be heated before cutting to facilitate cutting and prevent splitting. In the photo appreciate semi industrial shears which cuts the material. We did not have one of these, you can use a sharp chisel and a metal ruler and check off several times, until the court Bakelite.
Printing on Bakelite tracks
Place the frame on a flat, hard, smooth, with a few presses fixing hinge, allowing easily lift without running position. Bakelite placed just below the printed circuit pattern with tracks and adjust with tape or placing stoppers Bakelite built the same, so no smudging when printing site. Place the frame on top of Bakelite, leaving at least about 5 millimeters up of Bakelite, you can use a small piece of wood. Then we apply the ink UV or failing paint polyethylene, off the silk, making a way in the part before the drawing, and then draw the spatula ( squeegee or squeegee ), the design of the printed circuit on the surface of the cards. This process is not easy the first time and must practice until you form that perfect.
[hide]
Notice how it should be printing. It must be flawless, landslides or damage the printed spots.
After making all desired impressions is necessary to clean the accumulated ink silk because otherwise it would plug silk, spoiling. For this we use a tow varsol and clean silk. If you want to remove the PCB silk and enable it for another design, use chlorine or thinner to remove the circuit embodied in silk.
now proceed to the cards let dry before proceeding with development.
Stoving
The inks suitable for printing on Bakelite, are those that are not rolled or when immersed in acid card developer. In industry manufacture of printed inks are used to dry the exposure of UV rays, for its high resistance to solvents. For this we must make a UV oven, which can be manufactured in a home using a reflector street about 400W to 500W , and a metal box, but in this case we see that is wooden and has no problems. The bulbs used in outdoor lighting reflectors, emit ultraviolet rays in small quantities. These are sufficient to dry the UV paint. Should be left at least one printed Bakelite 10 minutes in the hormone. Before turning to the development of copper.
Copper corrosion of printed cards
Once dry the ink cards comes to bathe in ferric chloride. A container can be manufactured as the one shown in the picture, which uses a small electric pump, which maintains the moving ferric chloride.
corrosive action of ferric chloride acts on surfaces that are not covered by ink, thereby obtaining the circuit printed. If not able to make a developer like this, you can use a plastic bucket and shake hands with chloride with only one card at a time, until it has lost the excess copper and proceed with the next card.
When we see that all the excess copper has been removed from the card, remove from ferric chloride and proceed to remove the ink tracks protected from corrosion, washing first with water card, removing ferric chloride, then dipped in caustic soda dissolved in water for one minute and brush until all the paint has fallen. subsequently washed again with water, to remove the caustic soda. Dry well cards.
If the steps above are done meticulously, you get a card or PCB quality and presentation.
Drilling
Then holes are drilled all the cards, using a drill or a mototool tree. Bits should have different calibres, and that the legs of the components have different diameters[/hide].
Printing the antisolder on Bakelite
The solder mask ( Solder mask UV ) applies on the ski, in the same manner as the process used to apply paint to prepare printed circuit tracks. This painting is expensive. Protects copper tracks, rust and possible short circuits, also adding to form a very good presentation.
An economical way to do is paint mixing solder Dielectric Layer with a few drops of green vegetable dye. After applying the paint, using the frame that previously did with the corresponding acetate, dried, using a furnace ultra violet (UV).
The paint is dried antisolder UV, so the cards should bake 10 minutes.
To view larger picture and to observe in detail click on it.
Components printing mask
To print the mask components, each card is placed on the opposite side of the tracks and previously with the frame with acetate disclose this mask, draw with UV paint, ink, polyurethane or polyethylene white all cards, given that the holes must match the card with the drawings of the components.
The paint used industrially to make the mask component is also UV-drying, so the cards should bake 10 minutes. If your budget is low, you can use polyurethane paint, which is very strong, although not as much as the UV paint. But you can get an acceptable result with this painting.
After making all desired impressions is necessary to clean the accumulated ink silk, otherwise it would plug silk, spoiling. For this we use a tow varsol and clean silk. If you want to remove the PCB silk and enable it for another design, use chlorine or thinner to remove the circuit embodied in silk.
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