How to produce aluminum PCB

opening material

Material opening process

Incoming material → opening material → baking board

Incoming material: The raw material used for the production of aluminum based PCBs, also known as aluminum based copper clad laminate, is made by pressing a thermally conductive material or semi solidified sheet onto an aluminum plate with copper foil.

Cutting: Cutting is the process of cutting a large piece of material into small pieces using a machine according to different assembly requirements. After cutting, the edges of the plate are sharp, which can easily scratch your hands and cause scratches between the plates. Therefore, use a grinding machine to grind the edges after cutting.

Baked board

Baked Board Purpose:

① Eliminate the internal stress generated during the production of the sheet metal.

Improve the dimensional stability of the material

② Remove the moisture absorbed by the sheet during storage,

Increase the reliability of the material.

Baked board conditions:

Bake the plate at 150 ℃ for 4 hours, and the thickness of the laminated plate is usually 50 cm

A stack of meters

Purpose of material opening

Cut the large size incoming material into the size required for production

Precautions for material opening

① Check the size of the first piece after cutting

② Pay attention to aluminum surface scratches and copper surface scratches

③ Pay attention to plate edge delamination and flapping

Dry/wet film imaging

Wet film (also known as photosensitive circuit oil) and photosensitive dry film are both photosensitive materials. This material undergoes a polymerization reaction when exposed to ultraviolet light, forming a relatively stable image that does not dissolve in weak alkali, while the non photosensitive portion dissolves in weak alkali.

1. Dry/wet film imaging process

Grinding plate – film application – exposure – development

2. Purpose of dry/wet film imaging

Show the parts needed to make the circuit on the board

3. Dry/wet film imaging considerations

① Check for an open circuit in the wiring after development

② Is there any deviation in the development alignment to prevent dry film breakage

③ Pay attention to poor wiring caused by scratches on the board surface

④ No air residue during exposure to prevent poor exposure

⑤ After exposure, it should be stationary for more than 15 minutes before developing

Exposure:

The role of exposure is to sensitize some of the patterns on the film through the ultraviolet rays of the exposure machine, thereby transferring the patterns to the copper plate.

development:

Role of development:

“Removing the unexposed portion of the dry film, leaving a photosensitive portion.”.

Developing principle:

The unexposed portion of the photosensitive material did not undergo polymerization and was dissolved in the presence of a weak base Na2CO3 (0.8-1.2%). The polymerized photosensitive material is left on the board surface to protect the underlying copper surface from being dissolved by the etching solution.

Acid/alkaline etching

1. Acid/alkaline etching process

Etching – film removal – drying – plate inspection

2. Acid/alkaline etching purpose

After imaging the dry/wet film, retain the required portion of the line and remove any excess parts other than the line

3. Acid/Alkaline Etching Considerations

① Pay attention to unclean etching and excessive etching

② Pay attention to line width and line weight

③ Oxidation and scratching are not allowed on the copper surface

④ The drying film should be cleaned

The role of etching:

The copper surface of the unexposed portion is etched off.

Apocrine membrane

The film protecting the copper surface of the circuit is removed by using a higher concentration of NaOH (3-5%). The concentration of the NaOH solution should not be too high, otherwise it is easy to oxidize the board surface.

AOI process

The principle of this machine is to use the reflection effect of the copper surface to enable the graphics on the board to be scanned by the AOI machine and recorded in the software, and to check the defect points by comparing them with the data and graphics provided by the customer. Defects such as open circuits, short circuits, and poor exposure can be detected through the AOI machine.

Browning

The role of the browning process is to roughen the copper surface, increase the bonding area, and increase the surface adhesion.

Pressing plate

Process description: The pressing plate is a multilayer board that uses a semi cured sheet to connect the outer copper foil and the inner layer, as well as the inner and outer layers, into a whole.

Process principle: Utilizing the characteristics of semi solidified sheets, they melt at a certain temperature and become liquid to fill the graphic space, forming an insulating layer. After further heating, they gradually solidify to form a stable insulating material. At the same time, the layers of each line are connected into a single multilayer board.

What is a semi cured sheet (PP)?

Prepreg is an abbreviation for Pre pregnant. It is a sheet like adhesive material synthesized by resin and glass fiber carrier.

Resin – Usually a high molecular polymer, a thermosetting material. Currently, the commonly used resin is epoxy resin FR-4.

Drill hole

1. Drilling process

Pin driving – drilling – inspection plate

2. Purpose of drilling

Positioning and drilling the plate to assist in the subsequent production process and customer assembly

3. Precautions for drilling

① Check the number of holes drilled and the size of voids

② Avoid scratching of the sheet metal

③ Check the front edge of the aluminum surface and hole position deviation

④ Timely inspect and replace the drilling nozzle

⑤ Drilling is divided into two stages, one is drilling: drilling for peripheral tool holes after cutting;

Second drill: tool hole in the unit after resistance welding

Characteristics of aluminum PCB drilling nozzle

① Large chip removal space for drill bits: small chip removal resistance, smooth chip removal, low heat generation from drilling, reducing drilling contamination;

② Exceptional cutting edge sharpness: Due to the use of nanotechnology and advanced grinding processes, the cutting edge of the drill bit is sharper than before, which can reduce cutting force, reduce the rate of broken holes, and improve the quality of the hole wall;

③ Tool design based on customer applications: There are a variety of drill bits that can meet different application requirements. All parameters of the drill bit, such as core thickness and core taper, have been carefully designed, resulting in significant results;

④ The cutting edge is strictly symmetrical: it is conducive to efficient cutting and avoids drilling offset.

Copper deposition, full plate electroplating

Use chemical methods to deposit a layer of conductive metal in the hole of the drilled plate, and use full plate electroplating to thicken the metal layer to achieve the purpose of metallization in the hole, and make the circuit conductive

technological process:

Grinding plate → removing glue slag → depositing copper → electroplating the entire plate → next process

Electroless Copper Deposition, commonly known as copper deposition, is an autocatalytic chemical oxidation and reduction reaction in which Cu2+ions are reduced to metallic copper by electrons obtained during the electroless copper plating process, and the reductant emits electrons, which in turn is oxidized. Electroless copper plating is used as hole metallization in printed board manufacturing to complete the connection of wires between double-sided boards and multi-panel layers.

Screen printing, solder resistance, characters

1. Screen printing resistance welding, character flow

Screen printing – pre baking – exposure – development – characters

2. Purpose of screen printing solder mask and characters

① Soldering prevention: Protect lines that do not require soldering to prevent tin from entering and causing short circuits

② Character: used as a marker

3. Precautions for screen welding resistance and characters

① To check the board surface for debris or foreign matter

② Check the cleanliness of the screen board

③ Prebake for more than 30 minutes after screen printing to avoid bubbles in the wiring

④ Pay attention to the thickness and uniformity of the screen printing

⑤ After pre baking, the plate should be completely cooled to avoid staining the film or damaging the ink surface gloss

⑥ Place the ink surface downward during development

V-CUT, gong plate

1. V-CUT, gong board process

V-CUT – gong board – tear protective film – remove the front edge

2. Purpose of V-CUT and gongs

① V-CUT: Cut and connect a single PCS line with a small portion of the entire PNL plate to facilitate packaging and removal

use

② Gong board: remove excess parts from the circuit board

3. Precautions for V-CUT and gongs

① During the V-CUT process, pay attention to the size of V, the defects and burrs on the edges

② Pay attention to the burr and deviation of the gong blade when setting the gong plate, and timely inspect and replace the gong blade

③ Finally, avoid scratching the board surface when removing the front edge

Testing, OSP

1. Testing, OSP process

Line Test – Voltage Withstand Test – OSP

2. Purpose of testing, OSP

① Line test: detects whether the completed line is working properly

② Voltage withstand test: detect whether the completed line can withstand the specified voltage environment

③ OSP: Enables better soldering of circuits

3. Precautions for testing and OSP

① How to distinguish between qualified and unqualified products after testing

② Placement after OSP

③ Avoid line damage

FQC, FQA, packaging, shipping

1. Process

FQC – FQA – Packaging – Shipping

2. Purpose

① FQC conducts full inspection and confirmation of the product

② FQA spot check and verification

③ Packaging and shipping to customers as required

Aluminum PCB usage

1.Audio equipment: input and output amplifiers, balanced amplifiers, audio amplifiers, preamplifiers, power amplifiers, etc.

2.Power supply device: switch regulator, DC/AC converter, SW regulator, etc.

3.Communication electronic equipment: high-frequency amplifier, filter, and transmission circuit.

4.Office automation equipment: motor drivers, etc.

5.Automobile: electronic regulator, igniter, power controller, etc.

6.Computer: CPU board, floppy disk drive, power supply device, etc.

7.Power module: inverter, solid state relay, rectifier bridge, etc.

8.Lighting: With the promotion of energy-saving lamps, aluminum PCBs used for LED lamps have also begun to be widely used.