eagle single layer pcb

2023-01-03 14:31:19 eagle single layer pcb 92 Viewed

Eagle Single Layer PCB is usually made of phenolic paper-based single-sided copper clad laminate. It is a relatively simple Eagle single layer PCB with copper clad on one side and no copper clad on the other side. Eagle single layer PCB can only be wired on the copper clad side. Due to the simple implementation and low cost, the simple circuit design for mass production usually takes the form of eagle single layer PCB.

Manufacturing process of Eagle Single Layer PCB

①Blanking: Cut the entire copper clad laminate into eagle single layer PCB boards suitable for factory processing. Cutting is based on the customer's eagle single layer PCB size, processing unit, and panel size, and calculates the best eagle single layer PCB panel specification suitable for the production of the processing unit. In the PCB manufacturing industry, materials and costs are one of the most important indicators. Since the specifications of each batch of eagle single layer PCB orders may be different, it is necessary to calculate the respective materials and costs. Each batch of orders must be Determine an optimal material selection puzzle plan.

② Drilling: It is to use a drill to make holes of various shapes on the copper clad laminate, including round holes and special-shaped holes.

③Dry film coating: Paste the treated eagle single layer PCB with a dry anti-corrosion film by hot pressing. Structurally speaking, the dry film has three layers. The first layer is a polyethylene protective film; the second layer is a photoresist film; the third layer is a polyester film.

④ Exposure: Paste the film on the eagle single layer PCB and irradiate it with ultraviolet light. The black part in the film will not react because it is opaque; the white part absorbs light energy and decomposes into free radicals, which then trigger photopolymerization. The monomer undergoes polymerization and cross-linking reaction, and after the reaction, a three-dimensional macromolecular structure insoluble in dilute alkali solution is formed, and the exposure is completed.

⑤Development: Use developer solution (dilute alkali solution) to act on the dry film, the part that has not undergone chemical reaction is dissolved, and the part that has undergone chemical reaction will not be dissolved in the developer solution, and finally protects the copper surface of the eagle single layer PCB.

⑥ Etching: use the chemical solution to etch away the copper exposed after development to form a circuit pattern,

⑦Removing the film: use strong alkali to peel off the resist layer protecting the copper surface, exposing the circuit pattern,

⑧Solder resistance: Commonly known as "green oil", its function is to prevent soldering, leaving the through holes and pads to be soldered on the eagle single layer PCB board, covering all lines and copper surfaces, and preventing damage caused by wave soldering. Short circuit, and save the amount of solder; the second function is the shield: prevent moisture and various electrolytes from oxidizing the circuit and endangering electrical performance, and prevent external mechanical damage to maintain the good surface of the eagle single layer PCB Insulation; the third function is insulation: as the eagle single layer PCB is getting thinner and the distance between the wires is getting smaller and smaller, the insulation problem between the wires is prominent, and the solder resist paint can increase the insulation performance between the wires. In order to facilitate visual inspection, more green pigments that are helpful to the eyes are added to the main paint of the solder mask.

⑨Legend: Used as text or logo, which is convenient for customers to install and identify. The character ink of eagle single layer PCB requires three-dimensional printing, beautiful color, excellent solvent resistance, adhesion, electrical insulation and heat resistance. The colors are divided into white, yellow, black, red, blue and so on.

After the eagle single layer PCB has completed the solder mask and printing, the OSP anti-oxidation process is performed next. The complexation reaction between OSP potion and copper surface forms a thin organic film, which is used to prevent the oxidation of copper surface and protect the solderability of eagle single layer PCB. During the soldering process, the OSP film is dissolved in heat and flux acidic environment, exposing the inner layer Fresh copper finish.

After the eagle single layer PCB is manufactured, it must be inspected to ensure the quality of the eagle single layer PCB. Visual inspection is the most commonly used method. Use your eyes to see if there is a short circuit/open circuit on the surface circuit and whether the text mark can be clearly identified. There are also simple auxiliary tools such as rulers and magnifying glasses.

Obviously, eagle single layer PCB is the simplest structure, and the structure of eagle single layer PCB is more suitable for low density and simpler products. But this is not entirely the case. Some high-density packages also use the eagle single layer PCB metal structure. The conductors are only arranged to be molded on one side of the substrate. Additive, semi-additive and subtractive processes can all be used in the production of eagle single layer PCB.

Types of materials used in Eagle Single Layer PCB

(1) Phenolic paper substrate

Phenolic paper substrate (commonly known as, cardboard, rubber board, V0 board, flame retardant board, red letter copper clad laminate, 94V0. The most commonly used product models of phenolic paper based copper clad laminate are FR-1 (flame retardant) and XPC (non-flame retardant) Type) two. Eagle single layer PCB CCL can be easily judged from the color of the characters on the back of the board. Generally, the red letter is FR-1 (flame retardant), and the blue letter is XPC (non-flame retardant). This type of board is relatively different from other types. Boards are the cheapest.

(2) Epoxy glass fiber cloth substrate

Epoxy glass fiber cloth substrate (commonly known as: epoxy board, glass fiber board, fiber board, FR4) is also one of the materials used in eagle single layer PCB. Epoxy glass fiber cloth substrate is a kind of substrate with epoxy resin as adhesive and electronic grade glass fiber cloth as reinforcing material. Its bonding sheet and inner core thin copper clad laminate are important substrates for making multilayer circuit boards. The working temperature is high, and its performance is less affected by the environment. In terms of processing technology, it has great advantages over glass fiber cloth substrates made of other resins. This type of product is mainly used for double-sided PCB, which is also about twice as expensive as the phenolic paper substrate, and the common thickness is 1.5MM.

(3) Composite substrate

Composite substrate (commonly known as: powder board, etc., cem-1 board is also called 22F in some places in China) It mainly refers to CEM-1 and CEM-3 composite base copper clad laminates. At present, it is the most common material type used by eagle single layer PCB. The copper clad laminate made of wood pulp fiber paper or cotton pulp fiber paper as the core material and glass fiber cloth as the surface layer reinforcement material, both of which are impregnated with flame retardant epoxy resin, is called CEM-1. The copper clad laminate made of glass fiber paper as the core reinforcement material and glass fiber cloth as the surface layer reinforcement material is impregnated with flame retardant epoxy resin, which is called CEM-3. These two types of copper clad laminates are the most common eagle single layer PCB composite base copper clad laminates. This type of plate is cheaper than FR4 type plate.