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Production process of PCB circuit board

Huaqiang Express Circuit Board Co., Ltd. is a professional production line board manufacturer with advanced technology and strong quality and reputation. We have been continuously improving the quality of products to improve the company's credibility. With excellent product quality, prompt and timely delivery and thoughtful and meticulous service, it has won the praise of customers. We have gained good reputation and customer trust, and gradually become a reliable and long-term cooperative supplier of printed circuit boards and hard-and-soft composite boards.
Production process of PCB circuit board
Printed Circuit Board - Inner Circuit - Pressing - Drilling - Plating Through Hole (Primary Copper) - Outer Circuit (Secondary Copper) - Anti-Welding Green Paint - Text Printing - Contact Processing - Forming Cutting - Final Inspection Packaging.

Printed wiring boards and circuit configurations can be classified into three categories:

1. Single panel: The metal wires that provide the connection of parts are arranged on the insulated substrate material, which is also the support carrier for the installation of parts.

Double panel: When the one-sided circuit is insufficient to provide the connection requirement of electronic parts, the circuit can be arranged on both sides of the board, and through-hole circuit is laid on the board to connect the two sides of the board.

3. Multilayer board: In more complex application requirements, the circuit can be arranged into a multi-layer structure and pressed together, and a through-hole circuit is built between the layers to connect each layer of circuit. Inner circuit

Copper foil substrates are first cut into sizes suitable for processing and production. The copper foil on the surface of the substrate should be roughened properly by brushing, Micro-etching and other methods before pressing, and then the dry film photoresist should be adhered to it by appropriate temperature and pressure. When the substrate with dry film photoresistance is exposed in the ultraviolet exposure machine, the photoresistance will react with the ultraviolet radiation in the transparent area of the negative (the dry film in this area will be retained as an etching inhibitor in the later development and etching steps), and the line image on the negative will be transferred to the dry film photoresistance on the surface of the plate.

After tearing off the protective film on the film surface, the untouched areas on the film surface were removed by sodium carbonate aqueous solution, and then the exposed copper foil was corroded by hydrochloric acid and peroxide mixed solution to form a circuit. Finally, the successful dry film was washed out by sodium hydroxide solution.

4 For the inner circuit boards with more than six layers, the riveting datum holes corresponding to the inter-layer lines are punched out by the automatic positioning punch. After completion, the inner circuit board shall be bonded with the outer circuit copper foil with glass fibre resin film. Before bonding, the inner board needs to be treated by black (oxygen) to passivate the copper surface and increase the insulation, and to coarsen the copper surface of the inner circuit so as to produce good bonding performance with film.

When overlapping, the inner circuit boards with more than six layers of lines are riveted in pairs with riveting machines. Then, it is stacked neatly between the mirror steel plates with a full plate and fed into a vacuum press to harden and bond the film with appropriate temperature and pressure. The pressed PCB uses the target hole drilled by the X-ray automatic positioning drill as the reference hole for alignment of the inner and outer circuits. And the edge of the board is cut to facilitate subsequent processing.
The following is the introduction of the production process of PCB circuit board

First, open the material.

Purpose: According to the requirement of MI engineering data, on the large sheet which meets the requirement, the sheet is cut into small pieces to produce the sheet. The sheet meets the requirement of customers.

Flow: Large sheet metal Cutting plate according to MI requirement Laminating plate Beer fillet Grinding edge Outgoing plate

Two. Drilling

Purpose: According to the engineering data (customer data), drill the required aperture at the corresponding position on the sheet which meets the required size.

Process: laminated pin upper plate drilling lower plate inspection repair

Three. Copper precipitation

OBJECTIVE: Copper deposition is a chemical method to deposit a thin layer of copper on the wall of insulating holes.

Flow: Rough grinding hanging plate automatic copper sinking line lower plate dipping 1% dilute H2SO4 thickening copper

Four, graphics transfer

Objectives: Graphic Transfer is the image transfer on the production film board.

Process: (Blue Oil Process): Grinding Plate Printing First Side Drying Printing Second Side Drying Explosion Shadow Inspection; (Drying Film Process): Hemp Plate Pressing Film Static Position Exposure Static Position Photography Inspection

Five. Graphic plating

Objective: Graphic electroplating is to electroplate a required thickness of copper layer and a required thickness of gold, nickel or tin layer on the exposed copper skin or hole wall of the circuit.

Flow: upper plate degreasing washing twice micro corrosion washing pickling copper plating washing acid dipping tin plating washing lower plate

Six. Film withdrawal

Objective: To remove the anti-electroplating coating with NaOH solution and expose the copper coating on the non-line.

Flow: water film: socket alkali washing scrubbing passing machine; dry film releasing board passing machine

Seven. Etching

Aim: Etching is to use chemical reaction method to corrode the copper layer of off-line parts.

Eight, green oil

OBJECTIVE: Green oil is to transfer the picture of green phenanthrene to the board to protect the circuit and prevent tin on the circuit when welding parts.

Processes: grinding plate printing green oil plate exposure shadow; grinding plate printing the first side drying plate printing the second side drying plate

Nine, characters

Purpose: Characters are an easy-to-identify marker.

Procedure: Green oil end cooling and stationary adjusting screen printing characters back imprint

Ten. Gold-plated fingers

OBJECTIVE: To coat the plug finger with a required thickness of nickel and gold to make it harder and more wearable.

Process: upper plate degreasing washing twice micro-corrosion washing twice pickling copper plating washing nickel plating washing gold plating

Ten. Tinplate

AIM: Tin spraying is to spray a layer of lead and tin on the bare copper surface which is not covered with solder inhibitor oil to protect the copper surface from corrosion and oxidation, so as to ensure good solderability.

Process: micro-erosion air drying preheating rosin coating solder coating hot air leveling air cooling washing and air drying

Eleven. Molding

OBJECTIVE: To make gongs, beer boards, gongs and hand-cut by means of die stamping or NC gongs forming.

Explanation: Data gong machine board and beer board have higher accuracy, followed by hand gong, the lowest hand cutting board can only do some simple shape.

Twelve, test

AIM: To detect functional defects such as open circuit and short circuit, which are difficult to detect visually, by electronic 100% test.

Process: Upper die Placement Testing Qualified FQC visual inspection Unqualified Repair Back test OK REJ Scrap

Thirteen. Final inspection

Objective: To avoid the problem and defective plate outflow by 100% visual inspection and repair of slight defect.

Specific workflow: incoming materials checking data visual inspection qualified FQA spot check qualified packaging unqualified handling inspection of OK