{"id":1557,"date":"2025-12-12T09:32:56","date_gmt":"2025-12-12T09:32:56","guid":{"rendered":"https:\/\/fljpcb.com\/?page_id=1557"},"modified":"2025-12-15T01:39:02","modified_gmt":"2025-12-15T01:39:02","slug":"understanding-pcb-prototyping","status":"publish","type":"page","link":"https:\/\/fljpcb.com\/hy\/products-services\/understanding-pcb-prototyping\/","title":{"rendered":"Understanding PCB Prototyping"},"content":{"rendered":"
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What is PCB prototyping?<\/strong><\/h2>\n

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PCB prototyping means making printed circuit boards before mass production. Engineers design the circuit. Then they ask a board factory to make a small number of boards first. This step is for testing. Only when the prototype meets the test standards should the customer start full production. Prototyping lowers the risk of big mistakes in mass production. A printed circuit board is a very important part of any electronic product. Here are the usual steps of PCB prototyping.<\/p>\n

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\"Understanding<\/figure>\n

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Inner Layer Pattern (Inner Circuit)<\/h2>\n

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First, the copper clad laminate is cut to the right size for the process. Before the dry film photoresist is applied, the copper surface is made slightly rough to help glue stick. Then a dry film photoresist is pressed on the copper at the right temperature and pressure. Next the board goes into a UV exposure machine. The circuit image on the film is transferred to the dry film photoresist on the board. After the top protective film is peeled off, the unexposed parts of the resist are removed with a sodium carbonate (alkaline) solution. After that, a hydrogen peroxide-based solution is used to etch away the exposed copper, so the circuit pattern forms. Finally, the remaining dry film photoresist is washed off with a mild alkaline solution (for example, dilute sodium hydroxide) or another approved stripper.<\/p>\n

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Lamination (Pressing Layers Together)<\/h2>\n

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Before lamination, inner layers get a black oxide or other oxidation treatment. This makes the copper surface rough and helps glue stick. For multilayer boards (for example, six layers and above), the inner patterned layers are aligned with tooling pins or by a rivet\/stacking method. The layers are stacked with prepreg sheets and put between polished steel plates. Then the stack is put into a vacuum press. The press uses the right temperature and pressure to harden the prepreg and bond all layers into one board. After lamination, machines with X-ray or optical alignment drill reference holes. The board edges are cut to the right size for later steps.<\/p>\n

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Drilling<\/h2>\n

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A CNC drill machine drills through holes for layer-to-layer connections (vias) and holes for mechanical parts or through-hole components.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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Through-Hole Plating (Plating Vias)<\/h2>\n

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After the vias are formed, the hole walls need a thin metal layer so electricity can pass between layers. First the holes are cleaned by heavy brushing and high-pressure washing to remove burrs and dust. Then the clean hole walls are prepared and briefly tinned so metal can stick. Next the board goes through an electroless copper process (a chemical copper deposition). This deposits a thin copper layer on the hole walls and makes the via conductive. After that, the board can go through an electrolytic copper plating tank to thicken the copper in the via to the required thickness for later processing.<\/p>\n

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First Copper (Inner Copper Build)<\/h2>\n

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This step is the chemical copper deposition mentioned above. The thin copper from the chemical step makes the via conductive. Then electroplating with copper sulfate or a similar bath thickens the copper to the needed level.<\/p>\n

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Outer Layer Pattern and Second Copper (Outer Circuit)<\/h2>\n

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Transferring the pattern to the outer layer is similar to inner layers. For outer layers the etching process can use either a negative or positive photo method. In the negative method, after development the exposed copper is directly etched and the resist removed. This finishes the outer pattern. In the positive method, after development a second copper and a tin\/lead plating (or temporary plating) may be added. Then after removing the resist, an etchant such as an ammonia-based or copper chloride mix removes the unwanted copper, leaving the circuit. Finally a tin\/lead stripper removes the temporary tin\/lead layer if used.<\/p>\n

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Solder Mask and Silkscreen Printing<\/h2>\n

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The board house prints the required text, logo, and component marks by screen printing on the board. Then the ink is cured by heat or UV light so the printed marks harden.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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Pad and Contact Treatment<\/h2>\n

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Solder mask covers most copper areas. The board leaves exposed pads for components, test points, and connector contacts. These exposed pads need a protective finish to avoid oxidation. The finish must protect the board during storage and use so reliability is good.<\/p>\n

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Routing and Final Cut (Board Shape)<\/h2>\n

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The board is cut to the final shape by a CNC routing machine. After routing, dust and ionic dirt on the board are washed off.<\/p>\n

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Inspection and Packing<\/h2>\n

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At the end, the boards are inspected and then packed. Common packing ways include PE bag, heat-shrink wrap, and vacuum pack.<\/p>\n

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Differences Between PCB Manufacturing and PCB Prototyping (Clear Comparison)<\/h1>\n

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The text you gave had extra content that mixed other topics. Here I give a clear and simple comparison between PCB mass production<\/strong> and PCB prototyping<\/strong>:<\/p>\n

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        1. Purpose<\/strong>
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