The production of printed circuit boards, electronic enthusiasts tend to be more headache one thing, many electronics enthusiasts in order to produce a printed circuit board, often described using paint plates, Daoke, stickers, paste and other amateur production methods, speed slow, and difficult to produce high-quality printed circuit boards. Printed circuit board production even for many beginners into the electronic palace "stumbling block."
In today's increasingly popular computer aided design has become a hot topic in the electronic industry, the use of computer design PCB, though designed with a graphical specification, precise size, easy to modify, easy to save, etc., but the production of PCB process still more complicated, through light painting, and other chemical photogravure process, consumable materials more, a longer period, the higher the cost. Under normal circumstances, send e-mail to a printed circuit board factory with the fastest speed of the plate, and also need to be returned by courier week, about one hundred dollars. And a sophisticated circuit boards, often require several trial could be successful.
To solve these problems, we have gone through a long period of exploration and research, and finally developed an inexpensive, easy to use small fast printed circuit board production system. The system consists of a microcomputer CNC rapid thermal transfer plate making machine and a rapid erosion machine. Which inspired thermal transfer platesetter comes from studies of laser printers, our researchers found that laser printers we know, "Toner" is not the inorganic toner, but the black plastic particles containing magnetic material. It is affected by electrostatic attraction laser printer cartridges, toner cartridges arranged in a very high precision graphics and text, after the elimination of static electricity, the transfer of printing paper, and fixed high temperature hot melt to form a laser printer works.
Our researchers found clear in this, developed a non-stick properties of high temperature heat transfer paper, thermal transfer fast microcomputer numerical control machines and fast-plate etching machine. Using this system, you can very quickly for small batch production of printed circuit boards.
Significant Advantages
Using this system, you can very quickly for small batch production of printed circuit boards. The system with the conventional way of making traditional photographic plate has the following significant advantages compared to a circuit board technology:
(1)High precision version: to reach the plate precision laser printer resolution, in addition to the production of fine circuit pattern , but also to produce high-resolution images . Use it not only can produce fine printed circuit board, or even create beautiful metal signs, metal crafts such as painting.
(2) low platemaking costs: Make a circuit board plate fee is only equivalent to a thermal transfer paper costs.
(3) Engraving speed: fast thermal transfer platesetter laser printer can be printed on thermal paper schematics rapidly transferred to the board -shaped, corrosion-resistant layer is formed, a 200mm × 300mm making a printed circuit board, only requires only 10 to 20 minutes. Very suitable for factories, institutes, schools, shopping malls rapid production of electronic circuit board model to use.
(4) versatile: It can simultaneously produce a double-sided, single panel with the characters, can be divided into two characters making out with a double
Panel.
(5) high degree of automation, the operation extremely simple: rapid thermal transfer stencil machine, using 89c2051 for the main chip. Engraving machine for rubber roller temperature measurements and settings; circuit board into the exit; power is turned on, and shutdown to prevent cot designed motor over-temperature shutdown function are touch switch delay automatic control.
(6) Equipment Cost-effective: With this thermal transfer plate system rapidly replacing traditional PCB production process, low equipment prices,inexpensive, high cost, generally the month to invest in equipment for the rapid production of printed circuit board production and operation, the month to recover the full investment.
Operation and Working Principle
Platesetter operation and working principle: the printed circuit board will make a good graphics, a laser printer to print via specially treated special thermal paper, and then sent on transfer paper covered copper clad plate making machine with a computer plate.
The main principle of the platesetter using the principles of heat transfer, a laser printer with a similar structure, with two of the four special high temperature silicone composition of the cylindrical roller drive mechanism. The use of two infrared quartz heating tubes to which a group of two silicone cylindrical roller evenly heated to 180.5 ℃, while each set of two silicone cylindrical roller is two pressure rollers, its maximum surface temperature can reach 300 ℃ this two rubber rollers driven by a synchronous motor through the transmission system, the constant speed rotation of the two revolutions per minute. When the transfer paper with the copper clad nip through which the high temperature and greater pressure between the rollers on silica gel column, the adsorption of the toner will melt thermal transfer paper. Since the heat transfer paper is specially treated by polymer technology on its surface covered with a special coating several layers of materials, thermal transfer paper with a high temperature so that no adhesion properties. When the temperature reached 180.5 ℃, thermal transfer paper to melt the toner holding force of the sharp decline in the effect of the pressure, so that the toner is melted completely adsorbed on copper clad laminates, copper-clad cooled to form a tight printed graphics, the heat transfer process is completed.
The same principle, for the other side of the PCB transfer member row layout can also be carried out at the plate at the same time, so the PCB to achieve a more professional level. It should be noted here: the whole heat transfer process temperature requirements are particularly high, temperature control is very important.
For example: the melting temperature of the toner is generally the best point 180.5 ℃, when the temperature is too high, excessive melt toner will spread to four weeks of the original lines, causing blurred graphics, precision worse, serious cases will be scorched paper. When the temperature is too low or uneven temperature, poor transfer will occur, or even transfer. In actual use, the air temperature, humidity, the thickness of paper and board and other factors have an impact on the transfer efficiency, and therefore the quality of temperature control is very important to effect the transfer. For this thermal transfer platesetter thermostat sensor are imported pt-1000 -type thin film platinum resistance, so that temperature accuracy can reach 0.1 ℃, the plate to meet the requirements of high temperature. When the pattern is transferred to a copper-clad, that printer toner formed on the surface of a copper clad substrate with a protective layer pattern. Since the laser printer toners are made of a polymer material containing a resin made of the etching solution (fecl3 solution ) having good corrosion resistance, so that after the etching solution can be formed fecl3 work beautifully printed circuit board. In order to make quicker and more convenient corrode circuit boards, also need a circuit board etching machine for rapid corrosion, to save time, reduce waste fecl3 solution to improve efficiency. Quick etching machine fecl3 solution is rapidly heated to above 60 ℃, corrosion recycling small submersible pump to cycle through a special nozzle fecl3 solution was sprayed uniformly to the PCB. In the general case is heated to 80 ℃, fecl3 solution with a higher concentration of corrosion, corrosion 5-6 minutes completed. As a result of rapid corrosion process, the side etching can be reduced, so that the fine of the printed circuit board is more perfect and reliable. Fecl3 oxide by heating the solution to accelerate the reduction reaction, thereby accelerating the oxidation of copper into the surface of the copper-clad cu2 +; simultaneously take advantage of the impact of water deposited on the copper-clad surface and near cu2 +, faster chemical reaction sufficiently, this machine is especially suitable for the production of larger printed version. Throughout the corrosion process in semi-closed situation , with clean, reducing the advantages of corrosive liquid evaporates, so it is suitable for laboratories, research institutes, factories produce small quantities of printed circuit boards. After the printed circuit board corrosion, using a dedicated circuit board drill for drilling, on this special drill bit set with a cylinder, it completed the drilling speed can also be worn while drilling near the toner to form a very clean pad. To cover the remaining toner on the copper foil to form a good solder resist layer. The system can also make use of a metal plate, metal craft painting, also very beautiful, especially distinct levels, and low cost, coupled with the advantage of its fast -plate, I believe that in the near future in these industries can be more widely applications.
The system is made out of printed circuit boards accuracy can be achieved despite a very high professional level, but there are some drawbacks: Due to the different laser printers, weather humidity, heat transfer paper local defects and other reasons, there will Toner in thermal transfer paper attached to a bad local phenomenon. In addition the system is not yet equipped with CNC drilling, making double panel was also unable to carry out the hole of the metal, and thus need to be further improved.
Thermal transfer method making circuit boards, is to draw a good board graphics through a laser printer to print in thermal transfer paper, transfer paper and then covered in Bonded Copper, after heating to melt the toner deposited completely adsorbed on copper, etc. after cooling tear transfer paper, you can see the graphics board has been transferred to the Bonded Copper, the black anti-corrosion layer, that is, we want the PCB map, and finally eroded, namely we want to get the PCB board. Heating tools used in the production process is iron or presses.
Usage:
1. circuit board with a laser printer will print to the thermal circuit diagram of glossy paper
2. machine with a system board raised between 150-180 degrees Celsius, the heat transfer paper printed on one side of the circuit diagram deposited in the Bonded Copper for transfer; iron can also be used to replace the system board machine, manual transfer
3. After removing printed transfer paper, the Bonded Copper etched into ferric chloride solution
4. Finally, wash with gasoline Toner board
1. Introduction to Heat Transfer Act
Thermal transfer method is a method for rapid production of small batches of printed circuit boards. It uses anti-corrosion characteristics of the laser printer toner, with the system board quickly (20 minutes), high accuracy (width 15mil, spacing 10mil), low cost, etc., but the solder resist coating, and the like through hole metallization process limitations, this method can not produce any convenient dual-panel wiring, making only a single panel and so-called "quasi-double panel." Implement this method, you need the following equipment and materials: a computer a laser printer, printer toner compatible with cheap toner can; thermal transfer paper; iron a metal shell, with the so-called " heat transfer machine (with a laminator modified) "can be, the individual feels as effective as irons, and expensive; copper circuit board, glass epoxy substrate and has a Bakelite base, the latter's performance is better; corrosion and drug containers, the container with plastic boxes can, hydrochloric acid and hydrogen peroxide can be used medicines; drilling rig and drill bit, drill the general use of 0.8mm, 0.6mm and 1.0mm of; course there saws board, edging and a series of machine tools.
2. Design wiring rules
Since the heat transfer characteristics of the plate , in the wiring should note the following:
1) The width of not less than 15mil, line spacing is not less than 10mil. To ensure safety, the line width to the 25 ~ 30mil, high-current line broadening wiring in accordance with the general principles. Of Bouton lines, local can go to 20mil. 15mil should be used with caution. Wire spacing greater than 10mil, preferably greater than the pad pitch 15mil.
2) Try cloth into a single panel, you can consider when you can not jump through the cloth wiring. When you still can not pass the cloth may consider using double-sided, but considering the pad welding to weld both sides, side by side double or more columns packaging components do not set the pad toplayer. To rational distribution wiring might even be considered more than a single unit order replacement components (such as six non- gate) to facilitate Bouton. Try using manual routing, automatic routing often can not meet the requirements.
3) There are pads 0.8mm hole in the 70mil more to recommend 80mil. Otherwise, the accuracy is not high due to the punch to make the pad damage.
4) Diameter of holes can all be set to 10 ~ 15mil, not necessarily the actual size of the drill bit when drilling in order to facilitate the alignment.
5) bottomlayer words to write upside down, Toplayer positive with writing.
3. Print
Typesetting before printing, to fight for a piece of A4 lined paper figure, the better. Figure play out because some are bad, we need to choose a good seal. When discharged toplayer to flip over, double panel border must be retained in order to facilitate alignment. Then set up, set to black and white printing, actual size, turn off (hide) all the other layers toplayer, bottomlayer, borders and mutilayer addition. In thermal transfer paper and then print glossy.
4. Plus thermal transfer
Transfers will be selected on a good cut copper clad with iron (temperature to a maximum) can be attached to a heating slightly above, then continued evenly heated for several minutes, with a little beat when heated. Peel off the transfer paper is available until completely cooled. At this point if there are defects can be repaired with a marker.
5. Corrosion
Hydrochloric acid, hydrogen peroxide and water by approximately 2:1:1 with a good, put the printed Bonded Copper, constantly shaking for a few seconds to a few minutes can be good corrosion. Reaction equation 2HCl + H2O2 + Cu = CuCl2 + 2H2O, in addition there will be some pungent gases, HCl and H2O2 may be obtained by oxidation of Cl-Cl2 gas is volatile, so pay attention to ventilation. Also can be added HCl solution into Bonded Copper gradually adding H2O2, in order to facilitate control of the reaction, attention H2O2 can not directly onto the copper-clad, otherwise it will damage the toner.
6. Drilling and subsequent processing
After the corrosion of the circuit board drilling and milling processing, then fine sandpaper to remove the wet surface of the toner.
7. Welding
Before welding, can be coated with tin foil processing, but do not use solder paste. Before welding components, you should use the jumper pins and vias weld pass; sides of the pad should be double-sided welding.
A. Draw with protel PCB diagram, thermal transfer printing to paper (be careful not to print the top screen map
B. The thermal transfer paper, toner by heat transfer machine onto Bonded Copper
C. using ferric chloride corrosion after cleaning with gasoline appears as shown in Figure
D. circuit board drilling machine for drilling, welding experiment finished as shown below
Production of printed circuit board that is part of the CCL foil needs to stay put, to place unwanted eroded, and the rest of the circuit is what we want.
(1) selection
Select the function of the circuit according to the electrical and environmental conditions suitable PCB material, selected a suitable size CCL, with fine sandpaper to remove the oxide layer.
(2) cutting
CCL actual design size cut, and use flat Cuodao or emery cloth to four weeks polished smooth, burr.
(3) the cleaning sheet surface
The copper surface preparation and processing of CCL's first water sanding paper sanding a few times, then add water to the plate surface polished with a cloth, and finally with a dry cloth to wipe clean.
(4) pattern transfer
Pattern transfer is to a good PCB design drawings printed onto transfer paper, then cut down the garden will be a good map and plates, and other items can be fixed with tape from the printer according to a 1:1 ratio. The fixed plate into the map and have a good warm-end transfer machine. Board in the next, put in the figure, the feed button to start the transfer machine. By heating and pressing down the wheel, put the figure on the transfer paper to cover the copper foil.
(5) map
With advertising paper or transparent adhesive tape on one side covered with foil surface, remove with a knife after leaving Rio figure outside surface of the copper foil paper or graphical ads transparent tape, leaving the wire width and note pad size.
(6) Corrosion
The front of the processing circuit board into a good container filled with a corrosive liquid, and swaying back and forth. In order to accelerate the corrosion rate can increase the concentration of etching solution and heated, but the temperature should not exceed 50 ° C, otherwise it will destroy the cover film to make it fall off. Copper plate surface to be useless after all corroded immediately removed from the circuit board etching solution. The container has the function of heating and etching liquid flow to accelerate the etching rate.
(7) Rinse
Rinse with water corrosion good board, then wipe dry with a clean cloth.
(8) Remove the cover
Polished with sandpaper to remove the protective layer of clean, exposing the shiny foil.
(9) repair plate
The corrosion good board again with the original controls, the conductive strip edges smooth without burrs, solder mellow. Conductive strips with knife trim edges and pads.
(10) Drilling
The use of high-speed automatic punch or punch holes drilling. Holes must be drilled positive. Holes must be drilled in the center of the pad and perpendicular to the plate surface. When drilling, be sure to make the drilled hole finish, no glitches.
(11) The flux-coated holes drilled into the circuit board 5% to 10% sulfuric acid solution soak 3 ~ 5 min, subjected to a surface treatment. After removing rinse with water, then wipe the surface of the copper foil to clean and bright so far. Finally, the board can spray or brush to the flux baking hot. After drying the flux can be obtained the desired circuit board. Tu flux Day is easily welded to ensure conductivity, protection foil, to prevent rust. The main difference between the double-sided printed circuit board panel with a single panel that increases the hole metallization process, namely to achieve electrical connections on both sides of the printed circuit. Compared with the simple single-sided printed circuit board production, panel cleaning will be carried out after drilling, electroless copper, wipe the sink copper, copper plating thick, plugging holes, then before entering the pattern transfer and other operations. Multi-layer printed circuit board is a multilayer printed circuit board consisting of alternating layers of conductive and insulating materials graphic laminating adhesive made of a printed circuit board. Conductive pattern in two or more layers, layer electrical interconnection is achieved through metal hole: multilayer printed for general use epoxy glass cloth laminated board is PCB in high-tech products, its production technology PCB industry is the most influential and the most viable technology, which is widely used in military electronic equipment.
About PCBway
Since 2003 PCBWAY has been the leading PCB quick turn manufacturer specializing in both Prototype and Production quantities, Initially produced single-sided and double-sided printed circuit boards for the consumer electronics market. PCBWAY is ranked among the top 4 board fabricators in asia and is well-known for its expedited turn time capabilities and its reliable best on-time shipping record.
Today, we have over 450 operators with high modern facilities to manufacture multi-layer PCB up to 12 layers. Backing up with a group of professional engineers, and well established quality system. PCBWay has grown to become a major PCB manufacturer in Asia to serve in diverse customers base such as electronics appliance, communication, educational electronics, power supplies, Automationsetc.
Our mission is to become one of leading PCB manufacturer that provide in high quality product with total customer satisfaction.
